1. A printing apparatus, comprising:

an ink tank;

a print head for performing printing using the ink in the ink tank;

a light source that irradiates light into the ink tank;

a sensor that detects light incident from the ink tank during a period in which the light source emits light;

a processing unit that detects the amount of ink in the ink tank based on an output of the sensor,

the light source is turned on with a light amount based on a result of the sensor detecting light reflected from a region where the ink is not present.

2. Printing device according to claim 1,

the region is a region above the ink surface in the vertical direction.

3. Printing device according to claim 2,

the area is an area above the inlet of the ink tank in the vertical direction.

4. Printing device according to claim 1,

the region is a region of an end portion of the ink tank in a horizontal direction intersecting a vertical direction.

5. Printing device according to claim 4,

the area of the end portion is an area corresponding to the thickness of the side wall of the ink tank.

6. Printing device according to claim 1,

the region is a region provided on the lateral outer side of the ink tank.

7. Printing device according to claim 6,

further comprising a reflection member provided at the lateral outer side of the ink tank.

8. Printing device according to claim 1,

the region is a portion of the wall of the ink tank that is thicker than other portions.

9. Printing device according to one of the claims 1 to 8,

the light source is illuminated with a luminosity derived based on the result.

10. Printing device according to one of the claims 1 to 8,

the light source is illuminated at a time derived based on the result.

11. Printing device according to claim 1,

the processing unit adjusts the output of the sensor using a gain obtained based on the result.

12. Printing device according to claim 1,

the processing unit performs a process of adjusting the light amount of the light source so that the result becomes an adjustment target value.

13. Printing device according to claim 1,

the sensor includes a photoelectric conversion device, and an analog front-end circuit connected to the photoelectric conversion device.

14. Printing device according to claim 13,

the photoelectric conversion apparatus is a linear image sensor.

15. Printing device according to claim 14,

the linear image sensor is provided so that a longitudinal direction thereof is along a vertical direction.

Background

Conventionally, in a printing apparatus that performs printing using ink, a method of determining the presence or absence of ink in an ink container is known. For example, patent document 1 discloses an ink supply device that detects the liquid level of ink by receiving light emitted from a light emitter and transmitted through an ink bottle by a light receiver.

Further improvements in printing devices are currently required. For example, although there is a possibility that the accuracy of the ink amount detection process may be reduced due to a change in the characteristics of the light source that irradiates the ink tank with light, a method corresponding to the change is not disclosed in the conventional method such as patent document 1.

Patent document 1: japanese laid-open patent publication No. 2001-105627

Disclosure of Invention

One embodiment of the present disclosure relates to a printing apparatus including: an ink tank; a print head for performing printing using the ink in the ink tank; a light source that irradiates light into the ink tank; a sensor that detects light incident from the ink tank during a period in which the light source emits light; and a processing unit that detects an amount of the ink in the ink tank based on an output of the sensor, wherein the light source is turned on with an amount of light obtained based on a result of the sensor detecting the light reflected from the area where the ink is not present.

Drawings

Fig. 1 is a perspective view showing a structure of an electronic device.

Fig. 2 is a diagram illustrating the arrangement of ink tanks in an electronic device.

Fig. 3 is a perspective view of the electronic apparatus in a state where the cover of the ink tank unit is opened.

Fig. 4 is a perspective view showing the structure of the ink tank.

Fig. 5 shows an example of the structure of the printer unit and the ink tank unit.

Fig. 6 is an exploded view of the sensor unit.

Fig. 7 is a diagram showing a positional relationship among the substrate, the photoelectric conversion device, and the light source.

Fig. 8 is a cross-sectional view of the sensor unit.

Fig. 9 is a diagram illustrating a positional relationship between the light source and the light guide.

Fig. 10 is a diagram illustrating a positional relationship between the light source and the light guide.

Fig. 11 is a diagram illustrating a positional relationship between the light source and the light guide.

Fig. 12 is a perspective view showing another configuration of the sensor unit.

Fig. 13 is a sectional view showing another configuration of the sensor unit.

Fig. 14 is a diagram illustrating a positional relationship among the ink tank, the light source, and the photoelectric conversion device.

Fig. 15 is a diagram illustrating a positional relationship between the sensor unit and the ink tank.

Fig. 16 is a diagram illustrating a positional relationship between the sensor unit and the ink tank.

Fig. 17 is a diagram illustrating a positional relationship between the sensor unit and the ink tank in the carriage-mounted printing apparatus.

Fig. 18 shows an example of the structure of the sensor unit and the processing unit.

Fig. 19 is a configuration example of the photoelectric conversion device.

Fig. 20 is an example of pixel data as an output of a sensor.

Fig. 21 is a flowchart for explaining the ink amount detection processing.

Fig. 22 is an example of an ink tank including a background plate.

Fig. 23 is an example of pixel data in the case where an ink tank including a background plate is used.

Fig. 24 is a diagram illustrating a cross-sectional structure of the sensor unit and the ink tank.

Fig. 25 is a diagram illustrating a change in waveform due to calibration.

Fig. 26 is an example of a calibration area.

Fig. 27 is an example of a calibration area.

Fig. 28 is an example of a calibration area.

Fig. 29 is an example of a calibration area.

Fig. 30 is an example of a calibration area.

Fig. 31 is a flowchart for explaining the calibration process.

Fig. 32 is an example of a meniscus and an example of an image as a result of reading.

Fig. 33 is an example of a reading result with the dye ink as an object.

Fig. 34 is an example of a read result of a pigment ink as an object.

Fig. 35 is a perspective view of the electronic apparatus when the scanner unit is used.

Detailed Description

The present embodiment will be described below. The present embodiment described below is not intended to unduly limit the contents of the claims. Note that all the configurations described in the present embodiment are not necessarily essential structural elements. The embodiments described below may be combined with each other or may be replaced with each other.

1. Example of the configuration of electronic apparatus

1.1 basic Structure of electronic device

Fig. 1 is a perspective view of an electronic device 10 according to the present embodiment. The electronic apparatus 10 is a Multifunction Peripheral (MFP) including a printer unit 100 and a scanner unit 200. The electronic device 10 may have other functions such as a facsimile function in addition to the printing function and the scanning function. Alternatively, only the printing function may be provided. The electronic device 10 includes an ink tank unit 300 that stores an ink tank 310. The printer unit 100 is an inkjet printer that performs printing using ink supplied from the ink tank 310. Hereinafter, this description of the electronic device 10 may be referred to as a printing apparatus as appropriate.

In fig. 1, for convenience of explanation, a Y axis, an X axis orthogonal to the Y axis, and a Z axis orthogonal to the X axis and the Y axis are shown. In each of the XYZ axes, the direction of the arrow indicates a positive direction, and the direction opposite to the direction of the arrow indicates a negative direction. Hereinafter, the positive direction of the X axis is referred to as the + X direction, and the negative direction is referred to as the-X direction. The same applies to the Y axis and the Z axis. The electronic device 10 is disposed on a horizontal plane defined by the X axis and the Y axis in the use state, and the + Y direction is the front surface of the electronic device 10. The Z axis is an axis perpendicular to the horizontal plane, and the-Z direction is a vertical downward direction.

The electronic device 10 has an operation panel 101 as a user interface section. ON the operation panel 101, for example, key members for performing an ON/OFF operation (ON/OFF) of the power supply of the electronic apparatus 10, an operation related to printing using a print function, and an operation related to reading of a document using a scan function are arranged. Further, a display unit 150 for displaying an operation state of the electronic apparatus 10, a message, and the like is disposed on the operation panel 101. The display unit 150 displays the amount of ink detected by the method described later. Further, a reset button for causing the user to replenish ink in the ink tank 310 and execute reset processing may be arranged on the operation panel 101.

1.2 Printer Unit and scanner Unit

The printer unit 100 performs printing on a printing medium P such as printing paper by ejecting ink. The printer unit 100 has a housing portion 102 as a housing of the printer unit 100. A front face cover 104 is provided on the front side of the housing portion 102. The front face here indicates a face on which the operation panel 101 is provided, and indicates a face in the + Y direction in the electronic apparatus 10. The operation panel 101 and the front cover 104 are rotatable about the X axis with respect to the housing portion 102. The electronic device 10 includes a paper cassette, not shown, which is disposed in the-Y direction with respect to the front cover 104. The paper cassette is coupled to the front cover 104 and is detachably attached to the housing portion 102. In the + Z direction of the sheet cassette, a sheet discharge tray, not shown, is provided, and the sheet discharge tray can be extended and contracted in the + Y direction and the-Y direction. The discharge tray is disposed in the-Y direction with respect to the operation panel 101 in the state of fig. 1, and is exposed to the outside by rotating the operation panel 101.

The X-axis is the main scanning axis HD of the print head 107, and the Y-axis is the sub-scanning axis VD of the printer unit 100. A plurality of printing media P are loaded in a stacked state in a paper cassette. The printing media P loaded in the paper cassette are fed one by one along the sub-scanning axis VD into the housing portion 102, and after printing is performed by the printer unit 100, are discharged along the sub-scanning axis VD and loaded on the discharge tray.

The scanner unit 200 is loaded on the printer unit 100. The scanner unit 200 has a housing portion 201. The housing portion 201 constitutes a housing of the scanner unit 200. The scanner unit 200 is of a flat head type, and includes a document table formed by a transparent plate-like member such as glass, and an image sensor. The scanner unit 200 reads an image or the like recorded on a medium such as a sheet as image data via an image sensor. The electronic device 10 may also include an automatic paper feeder, not shown. The scanner unit 200 sequentially feeds a plurality of stacked originals while turning them over one by an auto sheet feeder, and reads them by an image sensor.

1.3 ink tank Unit and ink tank

The ink tank unit 300 has a function of supplying ink IK to the print head 107 included in the printer unit 100. The ink tank unit 300 includes a housing portion 301, and the housing portion 301 has a cover portion 302. A plurality of ink tanks 310 are housed in the housing 301.

Fig. 2 is a diagram showing a storage state of the ink tank 310. In fig. 2, the portion indicated by the solid line indicates the ink tank 310. The plurality of inks IK of different kinds are individually housed in the plurality of ink tanks 310. That is, the plurality of ink tanks 310 store different types of ink IK for each ink tank 310.

In the example of fig. 2, the ink tank unit 300 houses five ink tanks 310a, 310b, 310c, 310d, 310 e. In the present embodiment, five types of ink, two types of black ink, and yellow, magenta, and cyan color ink, are used as the types of ink. The two black inks are referred to as a pigment ink and a dye ink. The ink tank 310a contains ink IKa, which is a black ink as a pigment. The ink tanks 310b, 310c, and 310d contain color inks IKb, IKc, and IKd of yellow, magenta, and cyan, respectively. The ink tank 310e contains ink IKe, which is black ink as a dye.

The ink tanks 310a, 310b, 310c, 310d, and 310e are arranged in this order along the + X direction, and are fixed in the housing 301. Hereinafter, the five ink tanks 310a, 310b, 310c, 310d, and 310e and the five inks IKa, IKb, IKc, IKd, and IKe will be simply referred to as ink tank 310 and ink IK, unless otherwise specified.

In the present embodiment, each of the five ink tanks 310 is configured such that the ink IK can be filled into the ink tank 310 from the outside of the electronic device 10. Specifically, the user of the electronic device 10 injects the ink IK stored in another container into the ink tank 310 to replenish it.

In the present embodiment, the capacity of the ink tank 310a is larger than the capacities of the ink tanks 310b, 310c, 310d, and 310 e. The capacities of the ink tanks 310b, 310c, 310d, 310e are the same as each other. In the printer unit 100, a case is assumed where the pigment black ink IKa is consumed in a larger amount than the color inks IKb, IKc, IKd and the dye black ink IKe. The ink tank 310a containing the pigment black ink IKa is disposed at a position closer to the center of the electronic device 10 on the X axis. If such a configuration is adopted, for example, when the case portion 301 has a window portion for allowing a user to visually check the side surface of the ink tank 310, it is easy to check the remaining amount of ink that is frequently used. However, the arrangement order of the five ink tanks 310a, 310b, 310c, 310d, and 310e is not particularly limited. When any one of the inks IKb, IKc, IKd, and Ike other than the pigmented black ink IKa is consumed more, the ink IK may be stored in the ink tank 310a having a large capacity.

Fig. 3 is a perspective view of the electronic device 10 in a state where the lid portion 302 of the ink tank unit 300 is opened. The cover portion 302 is rotatable with respect to the outer case portion 301 via the hinge portion 303. When the cover 302 is opened, the five ink tanks 310 will be exposed. More specifically, the lid portion 302 is opened to expose five lids corresponding to the respective ink tanks 310, and the lid is opened to expose a part of the ink tanks 310 in the + Z direction. The part of the ink tank 310 in the + Z direction is a region including the ink inlet 311 of the ink tank 310. When the user injects the ink IK into the ink tank 310, the user pivots the lid 302 to open it upward, thereby approaching and operating the ink tank 310.

Fig. 4 is a diagram showing the structure of the ink tank 310. Further, the respective axes of X, Y, Z in fig. 4 indicate axes in a state where the electronic device 10 is used in a normal posture and the ink tank 310 is appropriately fixed to the case portion 301. Specifically, the X axis and the Y axis are axes along the horizontal direction, and the Z axis is an axis along the vertical direction. The respective axes of XYZ are similar to those in the following drawings unless otherwise specified. The ink tank 310 is a cube in which the ± X direction is the short side direction and the ± Y direction is the long side direction. Hereinafter, of the surfaces of the ink tank 310, the surface in the + Z direction is referred to as a top surface, the surface in the-Z direction is referred to as a bottom surface, and the surfaces in the ± X direction and the ± Y direction are referred to as side surfaces. The side surfaces correspond to first to fourth ink tank walls 316 to 319, which will be described later.

The ink tank 310 is formed of a synthetic resin such as nylon or polypropylene, for example. Alternatively, the ink tank 310 may be formed of acrylic or the like having a high transmittance. As will be described later with reference to fig. 22, the background plate 330 may be provided inside the ink tank 310, and various modifications may be made to the specific material, shape, and structure of the ink tank 310.

In the case where the ink tank unit 300 includes the plurality of ink tanks 310 as described above, the plurality of ink tanks 310 may be configured separately or integrally. When the ink tank 310 is integrally formed, the ink tank 310 may be integrally formed, or a plurality of ink tanks 310 formed separately may be integrally bundled or connected.

The ink tank 310 includes an inlet 311 into which the user injects the ink IK, and an outlet 312 from which the ink IK is discharged toward the print head 107. In the present embodiment, the top surface of the portion on the + Y direction side, which is the front of the ink tank 310, is higher than the top surface of the portion on the-Y direction side, which is the rear. An inlet 311 for injecting ink IK from the outside is provided on the top surface of the front portion of the ink tank 310. As described above with reference to fig. 3, the lid portion 302 and the lid are opened, thereby exposing the inlet 311. The user can replenish the ink IK of each color into the ink tank 310 by injecting the ink IK through the injection port 311. The ink IK for replenishing the ink tank 310 by the user is stored in a separate replenishing container and supplied to the tank. Further, a discharge port 312 for supplying ink to the print head 107 is provided on the top surface of the rear portion of the ink tank 310. By providing the inlet 311 at a position closer to the front surface of the electronic device 10, the ink IK can be easily injected.

1.4 other configurations of electronic devices

Fig. 5 is a schematic configuration diagram of the electronic device 10 according to the present embodiment. As shown in fig. 5, the printer unit 100 according to the present embodiment includes a carriage 106, a sheet feed motor 108, a carriage motor 109, a sheet feed roller 110, a processing unit 120, a storage unit 140, a display unit 150, an operation unit 160, and an external I/F (Interface) unit 170. In fig. 5, a specific structure of the scanner unit 200 is omitted. Fig. 5 is a diagram illustrating a connection relationship between the printer unit 100 and the ink tank unit 300, and is not a diagram limiting a physical structure or a positional relationship of the respective portions. For example, various embodiments are also contemplated for the arrangement of components such as the ink tank 310, the carriage 106, and the tube 105 in the electronic device 10.

A print head 107 is mounted on the carriage 106. The print head 107 has a plurality of nozzles that eject ink IK in the-Z direction, which is the bottom surface side of the carriage 106. A tube 105 is provided between the print head 107 and each ink tank 310. The inks IK in the ink tanks 310 are transported to the print head 107 via the pipes 105. The print head 107 ejects the inks IK conveyed from the ink tanks 310 as ink droplets from a plurality of nozzles onto the print medium P.

The carriage 106 is driven by a carriage motor 109 to reciprocate on the print medium P along the main scanning axis HD. The sheet feed motor 108 rotationally drives the sheet feed roller 110 and conveys the printing medium P along the sub-scanning axis VD. The ejection control of the print head 107 is performed by the processing unit 120 via a cable.

In the printer unit 100, printing on the printing medium P is performed by ejecting ink IK from a plurality of nozzles of the printing head 107 toward the printing medium P conveyed on the sub-scanning axis VD while moving the carriage 106 along the main scanning axis HD based on control of the processing unit 120.

One end of the main scanning shaft HD in the movement region of the carriage 106 becomes a home position region where the carriage 106 stands by. In the home position area, for example, a not-shown cover or the like for performing maintenance such as cleaning of the nozzles of the print head 107 is disposed. Further, in the movement area of the carriage 106, a waste ink cartridge or the like for storing waste ink when flushing or cleaning of the print head 107 is performed is disposed. The flushing is an operation of ejecting the ink IK from each nozzle of the print head 107 during printing of the print medium P, regardless of printing. The cleaning is an operation of cleaning the inside of the print head by sucking the print head by a pump or the like provided in the waste ink cartridge without driving the print head 107.

Here, a non-carriage-mounted printing apparatus in which the ink tank 310 is provided at a position different from the carriage 106 is assumed. However, the printer unit 100 may be a carriage-mounted printing apparatus in which the ink tank 310 is mounted on the carriage 106 and moved along the main scanning axis HD together with the print head 107. The carriage-mounted printing apparatus will be described later with reference to fig. 17.

The processing unit 120 is connected to an operation unit 160 and a display unit 150 as a user interface unit. The display unit 150 is a device for displaying various display screens, and can be realized by, for example, a liquid crystal display, an organic EL display, or the like. The operation unit 160 is a device for allowing a User to perform various operations, and can be implemented by various keys, a GUI (Graphical User Interface), or the like. For example, as shown in fig. 1, the electronic apparatus 10 includes an operation panel 101, and the operation panel 101 includes a display section 150, keys as an operation section 160, and the like. The display unit 150 and the operation unit 160 may be integrally formed by a touch panel. The processing unit 120 operates the printer unit 100 and the scanner unit 200 by the user operating the operation panel 101.

For example, in fig. 1, after an original is set on an original platen of the scanner unit 200, the user operates the operation panel 101, thereby starting the operation of the electronic apparatus 10. Then, the original is read by the scanner unit 200. Next, based on the image data of the read document, the printing medium P is fed from the paper cassette into the printer unit 100, and printing is performed on the printing medium P by the printer unit 100.

An external device can be connected to the processing unit 120 via the external I/F unit 170. The external device here is, for example, a PC (Personal Computer). The processing unit 120 performs control of receiving image data from an external device via the external I/F unit 170 and printing the image on the print medium P by the printer unit 100. The processing unit 120 also performs control for reading a document by the scanner unit 200 and transmitting image data as a result of the reading to an external device via the external I/F unit 170, or control for printing image data as a result of the reading.

The processing unit 120 performs, for example, drive control, consumption amount calculation processing, ink amount detection processing, and ink type determination processing. The processing unit 120 of the present embodiment is configured by hardware described below. The hardware may include at least one of a circuit that processes a digital signal and a circuit that processes an analog signal. For example, the hardware can be configured by one or more circuit devices and one or more circuit elements mounted on a circuit substrate. The one or more circuit devices are, for example, ICs or the like. The one or more circuit elements are for example resistors, capacitors, etc.

The processing unit 120 may be realized by a processor described below. The electronic device 10 of the present embodiment includes a memory that stores information, and a processor that operates based on the information stored in the memory. The information is, for example, a program and various data. The processor includes hardware. The Processor may be a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), a DSP (Digital Signal Processor), or other various processors. The Memory may be a semiconductor Memory such as an SRAM (Static Random Access Memory) or a DRAM (Dynamic Random Access Memory), a register, a magnetic storage device such as a hard disk device, or an optical storage device such as an optical disk device. For example, the memory stores a command that can be read by a computer, and by executing the command by the processor, the functions of the respective portions of the electronic device 10 are realized as processing. The command here may be a command constituting a command set of a program or a command instructing a hardware circuit of a processor to operate.

The processing unit 120 performs drive control for controlling the carriage motor 109 to move the carriage 106. Based on the drive control, the carriage motor 109 performs drive for moving the print head 107 provided on the carriage 106.

The processing unit 120 performs a consumption amount calculation process for calculating the ink consumption amount consumed by ejecting the ink IK from each nozzle of the print head 107. The processing unit 120 starts the consumption amount calculation processing with the state where the ink is filled in each ink tank 310 as an initial value. More specifically, when the user supplies the ink IK to the ink tank 310 and presses the reset key, the processing unit 120 initializes the count value of the ink consumption amount for the ink tank 310. Specifically, the count value of the ink consumption amount is set to 0. The processing unit 120 triggers the pressing operation of the reset key to start the consumption amount calculation process.

The processing unit 120 performs ink amount detection processing for detecting the amount of the ink IK stored in the ink tank 310 based on the output of the sensor unit 320 provided in association with the ink tank 310. The processing unit 120 performs an ink type determination process for determining the type of the ink IK stored in the ink tank 310 based on the output of the sensor unit 320 provided in association with the ink tank 310. The details of the ink amount detection process and the ink type determination process will be described later.

1.5 detailed configuration example of sensor Unit

Fig. 6 is an exploded perspective view schematically showing the structure of the sensor unit 320. The sensor unit 320 includes a substrate 321, a photoelectric conversion device 322, a light source 323, a light guide 324, a lens array 325, and a housing 326.

The light source 323 and the photoelectric conversion device 322 are mounted on the substrate 321. The photoelectric conversion device 322 is, for example, a linear image sensor in which photoelectric conversion elements are arranged in a predetermined direction. The line image sensor may be a sensor in which photoelectric conversion elements are arranged in a line, or a sensor in which photoelectric conversion elements are arranged in two or more lines. The photoelectric conversion element is, for example, PD (Photodiode). By using the linear image sensor, a plurality of output signals from a plurality of photoelectric conversion elements are obtained. Therefore, not only the presence or absence of the ink IK but also the position of the liquid surface can be estimated. The liquid surface may be referred to as an interface between ink and air.

The Light source 323 includes, for example, R, G, B Light Emitting Diodes (LEDs), and emits Light while switching R, G, B Light emitting diodes at high speed. Hereinafter, the light emitting diode of R is described as a red LED323R, the light emitting diode of G is described as a green LED323G, and the light emitting diode of B is described as a blue LED 323B. The light guide 324 is a rod-shaped member for guiding light, and may have a cross-sectional shape of a quadrangle, a circle, or another shape. The longitudinal direction of the light guide body 324 is a direction along the longitudinal direction of the photoelectric conversion apparatus 322. Since the light from the light source 323 is emitted from the light guide 324, the light guide 324 and the light source 323 may be collectively referred to as a light source when there is no need to distinguish the light guide 324 from the light source 323.

The light source 323, the light guide 324, the lens array 325, and the photoelectric conversion apparatus 322 are housed between the case 326 and the substrate 321. The case 326 is provided with a first opening 327 for a light source and a second opening 328 for a photoelectric conversion device. By making light emitted from the light source 323 incident on the light guide 324, the light guide emits light as a whole. The light emitted from the light guide 324 is irradiated to the outside of the case 326 through the first opening portion 327. Light from the outside is input to the lens array 325 through the second opening 328. The lens array 325 guides the input light to the photoelectric conversion device 322. The lens array 325 is, specifically, a self-focusing (SELFOC) lens array (SELFOC is a registered trademark) in which a large number of refractive index distribution type lenses are arranged.

Fig. 7 is a diagram schematically showing the arrangement of the photoelectric conversion apparatus 322. As shown in fig. 7, n photoelectric conversion devices 322 are arranged on a substrate 321 along a given direction, where n is an integer of 1 or more. Here, as shown in fig. 7, n may be an integer of 2 or more. That is, the sensor unit 320 includes a second linear image sensor disposed at a longitudinal direction side of the linear image sensor. Here, the linear image sensor is, for example, 322-1 of fig. 7, and the second linear image sensor is 322-2. As described above, each photoelectric conversion device 322 is a chip having a large number of photoelectric conversion elements arranged. Since the range of detecting incident light is made large by using the plurality of photoelectric conversion devices 322, the target range of ink amount detection can be made large. However, the number of the line image sensors, that is, the setting of the target range for detecting the amount of ink can be variously modified, and one line image sensor may be used.

Fig. 8 is a sectional view schematically showing the arrangement of the sensor unit 320. As is apparent from fig. 6 and 7, although the photoelectric conversion device 322 and the light source 323 do not overlap in position on the Z axis, fig. 8 shows the light source 323 for convenience of explanation of the positional relationship with other members. As shown in fig. 8, the sensor unit 320 includes a light-blocking wall 329 disposed between the light source 323 and the photoelectric conversion device 322. The light blocking wall 329 is, for example, a part of the housing 326, and is formed by extending a beam-like member between the first opening portion 327 and the second opening portion 328 to the substrate 321. The light blocking wall 329 blocks direct light from the light source 323 toward the photoelectric conversion apparatus 322. Since incidence of direct light can be suppressed by providing the light blocking wall 329, the detection accuracy of the amount of ink can be improved. Further, the specific shape is not limited to fig. 8 as long as the light blocking wall 329 can block direct light from the light source 323 toward the photoelectric conversion device 322. Further, as the light blocking wall 329, a member separate from the housing 326 may be used.

In consideration of the case where the ink amount is detected with high accuracy, the light irradiated to the ink tank 310 is preferably set to the same level regardless of the position in the vertical direction. As described later, this is because the presence or absence of the ink IK is reflected as a difference in luminance, and therefore, if a variation occurs in the amount of light irradiated, the accuracy is lowered. Therefore, the sensor unit 320 includes the light guide 324 arranged so that the longitudinal direction is perpendicular. The light guide 324 here is a rod-shaped light guide as described above. In addition, if it is considered that the light guide body 324 emits light uniformly, the light source 323 preferably emits light toward the light guide body 324 from a lateral direction, that is, a direction along the longitudinal direction of the light guide body 324. If such a method is adopted, total reflection tends to occur as the incident angle becomes large.

Fig. 9 to 11 are diagrams illustrating a positional relationship between the light source 323 and the light guide 324. For example, as shown in fig. 9, the light source 323 and the light guide 324 may be arranged side by side on the Z axis. The light source 323 can guide light in the longitudinal direction of the light guide 324 by irradiating light in the + Z direction. Alternatively, as shown in fig. 10, the end portion of the light guide 324 on the light source side may be curved. In this manner, the light source 323 can emit light in a direction perpendicular to the substrate 321, thereby guiding light in the longitudinal direction of the light guide 324. Alternatively, as shown in fig. 11, a reflection surface RS may be provided at the end portion of the light guide body 324 on the light source side. The light source 323 irradiates light in a direction perpendicular to the substrate 321. Light from the light source 323 is reflected on the reflection surface RS and guided in the longitudinal direction of the light guide 324. In addition, a known configuration can be widely applied to the light guide 324 in the present embodiment, such as providing a reflection plate on the surface of the light guide 324 in the-Y direction, and changing the density of the reflection plate according to the position of the light source 323. The light source 323 may be provided in the + Z direction with respect to the light guide 324, or the light sources 323 of the same color may be provided at both ends of the light guide 324, respectively, and the configurations of the light source 323 and the light guide 324 may be variously modified.

Fig. 12 is a perspective view showing another configuration of the sensor unit 320. Fig. 13 is a sectional view of the sensor unit 320 shown in fig. 12. As in the example described above with fig. 6, the sensor unit 320 includes a substrate 321, a photoelectric conversion device 322, a light source 323, a light guide 324, a lens array 325, and a housing 326.

As shown in fig. 12 and 13, the light-emitting surface of the light guide 324 may be inclined with respect to the substrate surface of the substrate 321 on which the photoelectric conversion device 322 is provided. As shown in fig. 13, light guide 324 irradiates light from light source 323 in a given range including the direction shown by a 1. The light emitted from the light guide 324 is reflected on the ink tank 310. As shown in a2, reflected light mainly in a direction orthogonal to the substrate surface of the substrate 321 is incident on the lens array 325, and the lens array 325 forms an image of the reflected light in the photoelectric conversion device 322. In this manner, the incident angle of the light from the light source 323 when entering the ink tank 310 can be adjusted. For example, in the embodiment in which the background plate 330 is provided inside the ink tank 310 as described later with reference to fig. 22, the incident angle is set so that the light emitted from the light source 323 through the light guide 324 can reach the background plate 330.

In fig. 12 and 13, the light source 323 is omitted. For example, the light source 323 is provided on the substrate 321, and irradiates light in a direction orthogonal to the substrate surface of the substrate 321 as illustrated in fig. 10 or 11. Alternatively, as shown in fig. 9, the light source 323 and the light guide 324 may be arranged side by side on the Z axis, and the light source 323 may emit light in the + Z direction or the-Z direction. In this case, for example, a substrate for the light source 323 may be provided separately from the substrate 321.

1.6 positional relationship between ink tank and sensor Unit

The sensor unit 320 may also have a fixed relative positional relationship with, for example, the ink tank 310. For example, the sensor unit 320 is bonded to the ink tank 310. Alternatively, the sensor unit 320 and the ink tank 310 may be provided with fixing members, respectively, and the sensor unit 320 may be attached to the ink tank 310 by fixing the fixing members by fitting or the like. The shape, material, and the like of the fixing member can be variously modified.

Fig. 14 is a diagram illustrating a positional relationship between the ink tank 310 and the sensor unit 320. As shown in fig. 14, the sensor unit 320 is fixed to any one wall surface of the ink tank 310 in a posture in which the longitudinal direction of the photoelectric conversion device 322 is the ± Z direction. That is, the photoelectric conversion device 322 as a linear image sensor is provided so that the longitudinal direction thereof is along the vertical direction. The vertical direction here indicates the direction of gravity and the opposite direction in the case where the electronic apparatus 10 is used in an appropriate posture.

In the example of fig. 14, the sensor unit 320 is fixed on the side of the ink tank 310 in the-Y direction. That is, the substrate 321 on which the photoelectric conversion device 322 is provided is closer to the discharge port 312 than the inlet 311 of the ink tank 310. Whether or not printing in the printer unit 100 can be executed is determined by whether or not the ink IK is supplied to the print head 107. Therefore, by providing the sensor unit 320 on the discharge port 312 side, the ink amount detection process can be performed for a position in the ink tank 310 where the ink amount is important in particular.

As shown in fig. 14, the ink tank 310 may include a main tank 315, a second discharge port 313, and an ink flow path 314. The main tank 315 is a portion of the ink tank 310 that is used to store the ink IK. The second discharge port 313 is, for example, an opening provided at the position closest to the-Z direction in the main tank 315. However, various modifications can be made to the position and shape of the second discharge port 313. For example, when suction by a suction pump or supply of pressurized air by a pressurization pump is performed on the ink tank 310, the ink IK stored in the main tank 315 of the ink tank 310 is discharged from the second discharge port 313. The ink IK discharged from the second discharge port 313 is guided in the + Z direction by the ink flow path 314, and is discharged from the discharge port 312 to the outside of the ink tank 310. At this time, as shown in fig. 14, by setting the positional relationship in which the ink flow path 314 and the photoelectric conversion device 322 do not face each other, it is possible to perform the detection processing of the appropriate amount of ink. For example, the ink flow path 314 is provided at an end in the-X direction in the ink tank 310, and the sensor unit 320 is provided at the + X direction compared to the ink flow path 314. In this manner, it is possible to suppress a decrease in the accuracy of the ink detection process due to the ink in the ink flow path 314. However, the discharge port 312 may be provided on a side surface or a bottom surface of the ink tank 310.

Further, at least a portion of the inner wall of the ink tank 310 facing the photoelectric conversion device 322 is preferably higher in ink repellency than the outer wall of the ink tank 310. Of course, the entire inner wall of the ink tank 310 may be processed so that the ink repellency is higher than the outer wall of the ink tank 310. The portion facing the photoelectric conversion device 322 may be the entire inner wall of the ink tank 310 in the-Y direction, or may be a part of the inner wall. The part of the inner wall specifically means a region including a portion of the inner wall in the-Y direction of the ink tank 310 at a position on the XZ plane overlapping with the photoelectric conversion device 322. When ink droplets adhere to the inner wall of the ink tank 310, the ink droplets are darker in the portion than in the portion where no ink is present. Therefore, the detection accuracy of the amount of ink may be lowered by the ink droplets. By improving the ink repellency of the inner wall of the ink tank 310, the adhesion of ink droplets can be suppressed.

The photoelectric conversion device 322 is provided in the range of Z1 to Z2, for example, on the Z axis. Z1 and Z2 are coordinate values on the Z axis, and Z1 < Z2. When the light from the light source 323 is irradiated on the ink tank 310, the ink IK filled in the ink tank 310 absorbs and scatters the light. Therefore, in the ink tank 310, the portion not filled with the ink IK becomes relatively bright, and the portion filled with the ink IK becomes relatively dark. For example, when the liquid surface of the ink IK is present at a position where the Z-axis coordinate value is Z0, the region where the Z-coordinate value is Z0 or less becomes dark, and the region where the Z-coordinate value is larger than Z0 becomes light in the ink tank 310.

As shown in fig. 14, by providing the photoelectric conversion device 322 so that the longitudinal direction thereof is perpendicular to the longitudinal direction, the position of the liquid surface of the ink IK can be appropriately detected. Specifically, if z1 < z0 < z2, the photoelectric conversion element arranged at the position corresponding to the range of z1 to z0 in the photoelectric conversion apparatus 322 has a relatively small amount of light being input, and therefore the output value becomes relatively small. Since the photoelectric conversion elements arranged at the positions corresponding to the ranges z0 to z2 have a relatively large amount of input light, the output value is relatively large. That is, based on the output of the photoelectric conversion device 322, z0 as the liquid surface of the ink IK can be estimated. Not only information on whether or not the ink amount is a binary value equal to or larger than a predetermined amount, but also a specific liquid surface position can be detected. If the position of the liquid surface is known, the amount of ink can also be determined in units of milliliters or the like based on the shape of the ink tank 310. Further, when the output value of the entire range from z1 to z2 is large, it can be determined that the liquid level is lower than z1, and when the output value of the entire range from z1 to z2 is small, it can be determined that the liquid level is higher than z 2. The range in which the amount of ink can be detected is the range in which the photoelectric conversion device 322 is provided, that is, the range from z1 to z 2. Therefore, the number of the photoelectric conversion devices 322 or the length of each chip is changed, so that the detection range can be easily adjusted.

The ink tank 310 and the sensor unit 320 may be in the positional relationship shown in fig. 14 or a positional relationship similar thereto when the ink amount detection process is performed, and the positional relationship is not limited to the fixed one.

Fig. 15 and 16 are perspective views illustrating a positional relationship between the ink tank 310 and the sensor unit 320 in the printing apparatus according to the present embodiment. As shown in fig. 15 and 16, the plurality of ink tanks 310 are arranged in the first direction. The first direction here is, for example, the ± X direction, and corresponds to the main scanning axis HD of the printing apparatus. Here, five ink tanks 310a to 310e are exemplified as the ink tank 310. Here, as shown in fig. 15 and 16, the sensor unit 320 may be relatively moved in the first direction with respect to the ink tank 310.

When the ink tank 310 and the sensor unit 320 are relatively movable in the X-axis direction, a state in which the ink tank 310a and the sensor unit 320 overlap each other in the X-axis direction as shown in fig. 15 and a state in which the ink tank 310b and the sensor unit 320 overlap each other in the X-axis direction as shown in fig. 16 can be switched. In the state shown in fig. 15, the sensor unit 320 can detect the amount of ink IKa contained in the ink tank 310 a. In the state shown in fig. 16, the sensor unit 320 can detect the amount of ink IKb contained in the ink tank 310 b. The same applies to the other ink tanks 310 such as the ink tanks 310c to 310 e.

Therefore, the ink amount detection processing and the ink type determination processing for the plurality of ink tanks 310 can be executed by a small number of sensor units 320, or in a narrow sense, by one sensor unit 320. As described later with reference to fig. 28 and 29, when calibration is performed by the end of the ink tank 310 or the reflecting member 350 provided separately from the ink tank 310, calibration data can be acquired by the sensor unit 320 for detecting the amount of ink. That is, it is not necessary to provide a separate sensor unit for calibration, and the structure can be simplified.

Fig. 17 is a diagram illustrating a positional relationship between the respective parts when the ink tank 310 and the sensor unit 320 are viewed in the + Z direction. As shown in fig. 17, the printing apparatus includes a carriage 106 that carries an ink tank 310 and moves relative to a housing. That is, the carriage 106 includes the ink tank 310 and the print head 107, and can move in the main scanning direction while mounting these two devices. The sensor unit 320 is fixed at a position outside the carriage 106. In this way, the positional relationship between the ink tank 310 and the sensor unit 320 can be adjusted by controlling the driving of the carriage 106. In addition, both the carriage 106 and the sensor unit 320 may be driven.

17. Detailed configuration examples of sensor unit and processing unit

Fig. 18 is a functional block diagram relating to the sensor unit 320. The electronic device 10 includes a processing section 120 and an AFE (Analog Front End) circuit 130. In this embodiment, the photoelectric conversion device 322 and the AFE circuit 130 are described as the sensor 190. The processing unit 120 is disposed on the second substrate 111. The processing section 120 corresponds to the processing section 120 shown in fig. 5, and outputs a control signal that controls the photoelectric conversion device 322. The control signals include a clock signal CLK and a chip enable signal EN1, which will be described later. The AFE circuit 130 is a circuit having at least a function of a/D converting an analog signal from the photoelectric conversion device 322. The second substrate 111 is, for example, a main substrate of the electronic device 10, and the substrate 321 is a sub-substrate for the sensor unit.

In fig. 18, the sensor unit 320 includes a red LED323R, a green LED323G, a blue LED323B, and n photoelectric conversion devices 322. As described above, n is an integer of 1 or more. The light source 323 includes a red LED323R, a green LED323G, and a blue LED323B, and a plurality of photoelectric conversion devices 322 are arranged on the substrate 321. A plurality of the red LEDs 323R, the green LEDs 323G, and the blue LEDs 323B may be provided.

The AFE Circuit 130 is implemented by, for example, an Integrated Circuit (IC). The AFE circuit 130 includes a non-volatile memory not shown. The nonvolatile memory here is, for example, SRAM. Note that the AFE circuit 130 may be provided on the substrate 321, or may be provided on a substrate different from the substrate 321.

The processing unit 120 controls the operation of the sensor unit 320. First, the processing unit 120 controls the operations of the red LED323R, the green LED323G, and the blue LED 323B. Specifically, the processor 120 supplies the driving signal DrvR to the red LED323R at a fixed exposure time Δ T at a fixed period T, and causes the red LED323R to emit light. Similarly, the processor 120 supplies the driving signal DrvG to the green LED323G for the exposure time Δ T at the cycle T to emit the green LED323G, and supplies the driving signal DrvB to the blue LED323B for the exposure time Δ T at the cycle T to emit the blue LED 323B. The processor 120 sequentially emits the red LED323R, the green LED323G, and the blue LED323B exclusively one by one during the period T.

The processing unit 120 controls the operation of the n photoelectric conversion devices 322(322-1 to 322-n). Specifically, the processing section 120 supplies the clock signal CLK to the n photoelectric conversion devices 322 in a shared manner. The clock signal CLK is an operation clock signal of the n photoelectric conversion devices 322, and each of the n photoelectric conversion devices 322 operates based on the clock signal CLK.

When each of the photoelectric conversion devices 322-j (j ═ 1 to n) receives the chip enable signal ENj after each of the photoelectric conversion elements receives light, a signal OS is generated and output based on the light received by each of the photoelectric conversion elements in synchronization with the clock signal CLK.

The processing unit 120 generates the chip enable signal EN1 that becomes active at a time until the photoelectric conversion device 322-1 finishes outputting the output signal OS after causing the red LED323R, the green LED323G, or the blue LED323B to emit light, and supplies the chip enable signal EN1 to the photoelectric conversion device 322-1.

The photoelectric conversion device 322-j generates the chip enable signal ENj +1 before ending the output of the output signal OS. The chip enable signals EN2 to ENn are supplied to the photoelectric conversion devices 322-2 to 322-n, respectively.

Thereby, after the red LED323R, the green LED323G, or the blue LED323B emits light, the n photoelectric conversion devices 322 sequentially output the output signals OS. Further, the sensor unit 320 outputs the output signals OS sequentially output by the n photoelectric conversion devices 322 from a terminal not shown. The output signal OS is transmitted to the AFE circuit 130.

The AFE circuit 130 sequentially receives the output signals OS sequentially output from the n photoelectric conversion devices 322, performs amplification processing or a/D conversion processing on each output signal OS, converts the output signal OS into digital data including a digital value corresponding to the amount of light received by each photoelectric conversion element, and sequentially transmits each digital data to the processing unit 120. The processing unit 120 receives the digital data sequentially transmitted from the AFE circuit 130, and performs ink amount detection processing and ink type determination processing, which will be described later.

Fig. 19 is a functional block diagram of the photoelectric conversion apparatus 322. The photoelectric conversion apparatus 322 includes a control circuit 3222, a voltage boosting circuit 3223, a pixel driving circuit 3224, p pixel portions 3225, a CDS (Correlated Double Sampling) circuit 3226, a sample hold circuit 3227, and an output circuit 3228. Note that the structure of the photoelectric conversion device 322 is not limited to fig. 14, and a modification may be made in which a part of the structure is omitted. For example, the CDS circuit 3226, the sample-and-hold circuit 3227, and the output circuit 3228 may be omitted, and the AFE circuit 130 may perform corresponding processing such as noise reduction processing and amplification processing.

The photoelectric conversion device 322 is supplied with a power supply voltage VDD and a power supply voltage VSS from two power supply terminals VDP and VSP, respectively. In addition, the photoelectric conversion device 322 operates based on the chip enable signal EN _ I, the clock signal CLK, and the reference voltage VREF supplied from the reference voltage supply terminal VRP. The power supply voltage VDD corresponds to a high potential side power supply, and is, for example, 3.3V. VSS corresponds to a low-potential-side power supply, and is, for example, 0V. The chip enable signal EN _ I is any one of the chip enable signals EN1 to Enn of fig. 18.

The chip enable signal EN _ I and the clock signal CLK are input to the control circuit 3222. The control circuit 3222 controls operations of the voltage boosting circuit 3223, the pixel driving circuit 3224, the p pixel portions 3225, the CDS circuit 3226, and the sample hold circuit 3227 based on the chip enable signal EN _ I and the clock signal CLK. Specifically, the control circuit 3222 generates a control signal CPC for controlling the voltage boosting circuit 3223, a control signal DRC for controlling the pixel driving circuit 3224, a control signal CDSC for controlling the CDS circuit 3226, a sampling signal SMP for controlling the sample hold circuit 3227, a pixel selection signal SEL0 for controlling the pixel portion 3225, a reset signal RST, and a chip enable signal EN _ O.

Booster circuit 3223 boosts power supply voltage VDD based on control signal CPC from control circuit 3222, and generates transmission control signal Tx that sets the boosted power supply voltage to a high level. The transfer control signal Tx is a control signal for transferring electric charges generated based on photoelectric conversion by the photoelectric conversion element during the exposure time Δ t, and is supplied to the p pixel portions 3225 in common.

The pixel driving circuit 3224 generates driving signals Drv for driving the p pixel portions 3225 based on the control signal DRC from the control circuit 3222. The p pixel portions 3225 are arranged in one-dimensional direction, and the driving signal Drv is transmitted to the p pixel portions 3225. Then, when the driving signal Drv is in an activated state and the pixel selection signal SELi-1 is in an activated state, the i-th pixel portion 3225 (i is any one of 1 to p) outputs a signal by setting the pixel selection signal SELi in an activated state. The pixel selection signal SELi is output to the i +1 th pixel portion 3225.

The p pixel portions 3225 include photoelectric conversion elements that receive light and perform photoelectric conversion, and output signals of voltages corresponding to the light received by the photoelectric conversion elements during the exposure time Δ t, based on the transfer control signal Tx, the pixel selection signal SEL (any one of SEL0 to SELp-1), the reset signal RST, and the drive signal Drv, respectively. Signals output from the p pixel portions 3225 are sequentially transmitted to the CDS circuit 3226.

The CDS circuit 3226 receives a signal Vo sequentially including signals output from the p pixel portions 3225, and operates based on a control signal CDSC from the control circuit 3222. The CDS circuit 3226 removes noise that is generated due to a characteristic variation of the amplifying transistors included in the p pixel portions 3225 and overlaps the signal Vo by correlated double sampling with reference to the reference voltage VREF. That is, the CDS circuit 3226 is a noise reduction circuit that reduces noise included in signals output from the p pixel portions 3225.

The sample hold circuit 3227 samples a signal from which noise is removed by the CDS circuit 3226 based on the sampling signal SMP, holds the sampled signal, and outputs the signal to the output circuit 3228.

The output circuit 3228 amplifies the signal output by the sample-and-hold circuit 3227, thereby generating an output signal OS. As described above, the output signal OS is output from the photoelectric conversion device 322 via the output terminal OP1, and is supplied to the AFE circuit 130.

The control circuit 3222 generates the chip enable signal EN _ O as a high pulse signal just before the end of the output signal OS from the output circuit 3228, and outputs the photoelectric conversion device 322 of the next stage from the output terminal OP 2. The chip enable signal EN _ O here is any one of the chip enable signals EN2 to ENn +1 in fig. 13. Thereafter, the control circuit 3222 causes the output circuit 3228 to stop outputting the output signal OS, and further sets the output terminal OP1 to a high impedance.

As described above, the sensor 190 of the present embodiment includes the photoelectric conversion device 322 and the AFE circuit 130 connected to the photoelectric conversion device 322. If such a manner is adopted, appropriate pixel data can be output based on the output signal OS output from the photoelectric conversion apparatus 322. The output signal OS is an analog signal, and the pixel data is digital data. For example, the sensor 190 outputs the number of pixel data corresponding to the number of photoelectric conversion elements included in the photoelectric conversion device 322.

2. Ink quantity detection processing

2.1 outline of ink amount detection processing

Fig. 20 is a schematic diagram showing a waveform of pixel data as an output of the sensor 190. As described above with reference to fig. 18, the output signal OS of the photoelectric conversion device 322 is an analog signal, and pixel data as digital data is acquired by a/D conversion performed by the AFE circuit 130.

The horizontal axis of fig. 20 represents a position in the longitudinal direction of the photoelectric conversion device 322, and the vertical axis represents a value of pixel data corresponding to the photoelectric conversion element disposed at the position. Fig. 20 is a waveform showing, for example, any one of an R signal corresponding to the red LED323R, a G signal corresponding to the green LED323G, and a B signal corresponding to the blue LED 323B.

When the longitudinal direction of the photoelectric conversion device 322 is the vertical direction, the left direction of the horizontal axis corresponds to the-Z direction, and the right direction corresponds to the + Z direction. If the positional relationship between the photoelectric conversion device 322 and the ink tank 310 is known, each photoelectric conversion element can be made to correspond to the distance of the ink tank 310 from the reference position. The reference position of the ink tank 310 is, for example, a position corresponding to the inner bottom surface of the ink tank 310. The inner bottom surface is the position of the lowest assumed ink level.

The pixel data corresponding to one photoelectric conversion element is, for example, 8-bit data and has a value in the range of 0 to 255. The value on the vertical axis may be data obtained by performing calibration or the like described later with reference to fig. 25 or the like. The pixel data is not limited to 8 bits, and may be other bits such as 4 bits or 12 bits.

As described above, the photoelectric conversion element corresponding to the region where the ink IK is not present receives a relatively large amount of light, and the photoelectric conversion element corresponding to the region where the ink IK is present receives a relatively small amount of light. In the example of fig. 20, the value of the pixel data is large in the range shown by D1, and the value of the pixel data is small in the range shown by D3. In the range indicated by D2 between D1 and D3, the value of the pixel data changes greatly with respect to the change in position. That is, in the range of D1, there is a high possibility that ink IK does not exist. In the range of D3, the ink IK is highly likely to be present. The liquid level, which is the boundary between the region where the ink IK is present and the region where the ink IK is not present, is highly likely to be within the range D2.

The processing unit 120 performs ink amount detection processing based on the pixel data output from the sensor 190. Specifically, the processing unit 120 detects the position of the liquid surface of the ink IK based on the pixel data. As shown in fig. 20, the liquid level of the ink IK is considered to exist at any position of D2. Therefore, the processing unit 120 detects the liquid level of the ink IK based on the predetermined threshold Th which is smaller than the value of the pixel data at D1 and larger than the value of the pixel data at D3.

If this is done, the amount of ink contained in the ink tank 310 can be detected using the photoelectric conversion device 322 as a linear image sensor. The information directly obtained using Th is the relative position of the ink surface with respect to the photoelectric conversion device 322. Therefore, the processing unit 120 may calculate the remaining amount of the ink IK based on the position of the liquid surface.

When all the pixel data is larger than Th, the processing unit 120 determines that the ink IK is not present in the range to be detected for the amount of ink, that is, the liquid surface is located at a position lower than the end point of the photoelectric conversion device 322 in the-Z direction. In addition, when all the pixel data is smaller than Th, the processing portion 120 determines that the target range of the ink amount detection is filled with the ink IK, that is, the liquid surface is located at a position higher than the end point of the photoelectric conversion device 322 in the + Z direction. It may also be determined that an abnormality has occurred if there is no possibility that the liquid level is at a position higher than the end point in the + Z direction of the photoelectric conversion apparatus 322.

The ink amount detection process is not limited to the process using the threshold Th in fig. 20. For example, the processing unit 120 performs processing for obtaining the slope of the graph shown in fig. 20. The slope is, specifically, a differential value, more specifically, a differential value of adjacent pixel data. The processing unit 120 detects a point where the slope is larger than a predetermined threshold value, more specifically, a position where the slope is the maximum, as the position of the liquid surface. When the maximum value of the obtained slopes is equal to or less than the predetermined slope threshold, the processing unit 120 determines that the liquid surface is located at a position lower than the end point of the photoelectric conversion device 322 in the-Z direction or at a position higher than the end point of the photoelectric conversion device 322 in the + Z direction. Which side the liquid level is located on can be identified from the value of the pixel data.

When the sensor 190 can receive a plurality of kinds of light having different wavelength bands, the ink amount detection process may be performed based on the result of receiving light of one kind of light. For example, as described later with reference to fig. 32 and the like, it may be determined whether or not to perform the ink amount detection process using pixel data corresponding to a certain type of light based on the characteristics of the pixel data in the meniscus portion. Alternatively, the processing unit 120 may specify the position of the liquid surface by using each pixel data, and determine the final position of the liquid surface based on the specified position. For example, the processing unit 120 determines, as the liquid surface position, a liquid surface position obtained based on the pixel data of R, a liquid surface position obtained based on the pixel data of G, an average value of liquid surface positions obtained based on the pixel data of B, and the like. Alternatively, the processing unit 120 may obtain synthesized data obtained by synthesizing three pixel data of RGB, and obtain the position of the liquid surface based on the synthesized data. The synthesized data is, for example, average data obtained by averaging RGB pixel data at each point.

Fig. 21 is a flowchart for explaining the processing including the ink amount detection processing. When the process is started, the processing unit 120 performs control for causing the light source 323 to emit light (S101). While the light source 323 emits light, reading processing using the photoelectric conversion device 322 is performed (S102). In the case where the light source 323 includes a plurality of LEDs, the processing section 120 sequentially performs the processes of S101 and S102 for each of the red LED323R, the green LED323G, and the blue LED 323B. Through the above processing, three pixel data of RGB are obtained.

Next, the processing unit 120 performs a process of detecting the amount of ink based on the acquired pixel data (S103). As described above, the specific processing of S103 can be implemented in various modifications such as comparison with the threshold Th, detection of the maximum value of the slope, and the like.

The processing unit 120 determines the amount of the ink IK filled in the ink tank 310 based on the position of the detected liquid surface (S104). For example, the processing unit 120 sets the ink amounts in three stages of "large remaining amount", "small remaining amount", and "used up ink" in advance, and determines which of the ink amounts the current ink amount belongs to. The large remaining amount indicates a state in which the ink IK remains in a sufficient amount and the user does not need to respond to the ink IK during continuous printing. The small remaining amount means a state in which the amount of ink is reduced and replenishment by a user is desired although printing itself can be continued. The ink end refers to a condition indicating that the amount of ink has significantly decreased and that the printing operation should be stopped.

If it is determined in the process of S104 that the remaining amount is large (S105), the processing unit 120 ends the process without performing notification or the like. If it is determined in the process of S104 that the remaining amount is small (S106), the processing unit 120 performs a notification process of prompting the user to replenish the ink IK (S107). The notification processing is performed by displaying a text or an image on the display unit 150, for example. However, the notification process is not limited to display, and may be notification by illuminating a light emitting unit for notification, notification by sound using a speaker, or notification by combining these modes. If it is determined in the process of S104 that the ink is used up (S108), the processing unit 120 executes a notification process for prompting the user to replenish the ink IK (S109). The notification processing in S109 may be the same as the notification processing in S107. However, as described above, the ink is used up in a state where it is difficult to continue the printing operation and the remaining amount is severe compared to a small amount. Therefore, the processing unit 120 may perform the notification processing different from S107 in S109. Specifically, in S109, the processing unit 120 may execute processing for prompting the user to supplement the content of the ink IK more strongly than in S107, increasing the light emission frequency of the light, increasing the sound, and the like, in the displayed text. The processing unit 120 may perform processing, not shown, such as control for stopping the print job after the processing of S109.

The trigger for executing the ink amount detection process shown in fig. 21 can be set in various ways. For example, the start of execution of a given print job may be used as an execution trigger, or the elapse of a predetermined time may be used as an execution trigger.

The processing unit 120 may store the ink amount detected by the ink amount detection processing in the storage unit 140. Then, the processing unit 120 performs processing based on the detected time-series change in the amount of ink. For example, the processing unit 120 obtains the ink increase amount or the ink decrease amount based on the difference between the ink amount detected at a predetermined timing and the ink amount detected at a timing before the predetermined timing.

Since the ink IK is used for printing, head cleaning, or the like, it is natural to reduce the amount of ink as the operation of the electronic device 10. However, the consumption amount of the ink IK per unit time during printing or the consumption amount of the ink IK per head cleaning is determined to some extent, and if the consumption amount is extremely large, some abnormality such as ink leakage may occur.

For example, the processing unit 120 obtains a standard ink consumption amount assumed in printing or the like in advance. The standard ink consumption amount may be determined based on the expected ink consumption amount per unit time or may be determined based on the expected ink consumption amount per job. The processing unit 120 determines that the ink consumption amount obtained by the time-series ink amount detection processing is not less than a predetermined amount greater than the standard ink consumption amount. Alternatively, the processing unit 120 may perform a consumption amount calculation process for calculating the ink consumption amount by counting the number of times the ink IK is ejected. In this case, the processing unit 120 determines that the ink consumption amount calculated by the time-series ink amount detection process is abnormal when the ink consumption amount is larger than the ink consumption amount calculated by the consumption amount calculation process by a predetermined amount or more.

If it is determined to be abnormal, the processing unit 120 sets the abnormality flag to on. If this is done, some error processing can be performed in the case where the amount of ink is excessively reduced. Various processing in the case where the abnormality flag is set to on are considered. For example, the processing unit 120 may execute the ink amount detection process shown in fig. 21 again using the abnormality flag as a trigger. Alternatively, the processing unit 120 may execute a notification process for prompting the user to confirm the ink tank 310 based on the abnormality flag.

In addition, the amount of ink is increased by the user replenishing the ink IK. However, it is considered that the amount of ink increases even when the ink IK is not replenished, for example, a temporary change in the liquid level due to shaking of the electronic apparatus 10, a reverse flow of the ink IK from the tube 105, a detection error of the photoelectric conversion apparatus 322, and the like. Therefore, when the ink increment is equal to or less than the predetermined threshold, the processing unit 120 determines that the ink IK is not replenished and the increment is within an allowable error range. In this case, since it is determined that the change in the ink amount is normal, no additional processing is particularly performed.

On the other hand, when the ink increase amount is larger than the given threshold, the processing unit 120 determines that the ink IK has been replenished and sets the ink replenishment flag to on. The ink replenishment mark is used as a trigger for executing the ink type determination process described later, for example. The ink replenishment flag may be used as a trigger for the process of resetting the initial value in the consumption amount calculation process.

However, even when the ink increase amount is larger than the predetermined threshold, it is impossible to deny the possibility that a large error is generated to an unacceptable extent due to some abnormality. Therefore, the processing unit 120 may perform a notification process of determining whether or not the input of the ink IK is added to the user, and determine whether to set the abnormality flag or set the ink addition flag based on the input result of the user.

2.2 example Using background plate

As described above, various materials such as polypropylene can be used for the ink tank 310. The transmittance of the ink tank 310 varies depending on the material of the ink tank 310, or depending on the conditions such as the temperature at which the ink tank 310 is molded. The transmittance here indicates a ratio of the intensity of light incident on a given object to the intensity of light after passing through the object. For example, a transmittance of 50% for a given object means that the intensity of light is attenuated by half by passing through the object. The transmittance of the ink tank 310 is, for example, a transmittance in one wall surface of the ink tank 310, and represents an intensity ratio of light incident from the sensor unit 320 to the side surface on the + Y direction side of the ink tank 310 to light transmitted through the side surface on the + Y direction side and entering the inside of the ink tank 310.

For example, in polypropylene, light is absorbed and scattered by fine particles present inside, and the transmittance may be lowered. When the transmittance is lower to some extent than 100%, the light incident on the ink tank 310 is reflected or scattered on the wall surface or inside the wall of the ink tank 310. The wall surface here includes both the outer wall and the inner wall. Therefore, the ink tank 310 becomes a light guide body, and a place where the light of the ink tank 310 is not irradiated is caused to emit light. As described above, there is a difference that light is absorbed by the ink IK in the region where the ink IK is present, and light is not absorbed in the region where the ink IK is not present. Due to this difference, the light from the ink tank 310 as a light guide has a characteristic that the amount of light from the area where the ink IK exists is small, and the amount of light from the area where the ink IK does not exist is large. Therefore, the ink amount detection based on the pixel data can be realized as described above.

However, when the transmittance is low, light is likely to be scattered on the wall of the ink tank. Therefore, light from a predetermined position in the ink tank 310 is diffused in the ± Z direction. As a result, in the vicinity of the liquid surface, the region where no ink is observed is darker to some extent, and the region where ink is observed is lighter to some extent. For example, if the ink tank wall is considered to be ground glass, it is easy to understand that the liquid surface is observed in a blurred state by passing through the ink tank wall.

As a result, as shown in D2 in fig. 20, the region where the liquid level is highly likely to exist has a certain degree of width in the ± Z direction. In other words, the slope of the pixel data output from the sensor 190 becomes small. When the liquid level is determined based on the comparison with the predetermined threshold value Th, if the inclination of the pixel data is small, the position of the liquid level as a result of the determination is largely changed according to the setting of Th. For example, even if it is known that the threshold value Th is appropriately a value of about 50 to 100, the difference between the liquid surface positions when Th is 50 and when Th is 100 is large. Therefore, in order to detect the liquid level with high accuracy, it is necessary to strictly set the threshold Th. Alternatively, calibration described later needs to be performed accurately in advance.

In contrast, it is expected that the inclination of the pixel data is also increased by increasing the transmittance of the ink tank 310. The high transmittance makes scattering and absorption on the wall surface difficult. Therefore, the diffusion of light is suppressed, and light from within the ink tank 310 easily reaches the lens array 325 and the photoelectric conversion device 322 while maintaining the position on the Z axis.

However, when the transparency is high, the amount of reflected light may be reduced. For example, in the case where all the surfaces of the ink tank 310 are completely transparent, the light irradiated from the sensor unit 320 passes through the region where the ink IK is not present and is emitted from the side in the-Y direction or the like. In other words, the ink tank 310 does not emit light as a light guide. In this case, since light does not return from the area where the ink IK does not exist, pixel data in the area does not become large. Although the reflected light generated by the ink IK returns from the region where the ink IK exists, the amount of light is small as described above with reference to fig. 20 and the like. That is, if the transmittance of the ink tank 310 is simply increased, the value of the pixel data may be reduced regardless of the presence or absence of the ink IK, and the detection of the ink amount may be difficult.

Fig. 22 is a schematic diagram showing the structure of the ink tank 310. Although fig. 22 illustrates an example in which the ink tank 310 is a rectangular parallelepiped by simplifying the shape thereof, the ink tank 310 may have a shape as shown in fig. 4, for example, or may have another shape. Ink tank 310 includes a first ink tank wall 316 corresponding to sensor cell 320, and a second ink tank wall 317 opposite the first ink tank wall. For example, first ink tank wall 316 is a side in the-Y direction, and second ink tank wall 317 is a side in the + Y direction. Further, the ink tank 310 includes a third ink tank wall 318 as a right side surface and a fourth ink tank wall 319 as a left side surface when viewed from the sensor unit 320. The left-right direction here refers to a direction in which the ink tank 310 is viewed from the sensor unit 320 and a direction perpendicular to the vertical direction, and for example, the + X direction is the left direction and the-X direction is the right direction.

As shown in fig. 22, the printing apparatus according to the present embodiment may include a background plate 330 inside the ink tank 310. Specifically, the backlight unit may include a background plate 330, and the background plate 330 may be disposed between the first ink tank wall 316 and the second ink tank wall 317 and opposed to the light source 323 and the sensor 190. As described above, first ink tank wall 316 is the side opposite light source 323 and sensor 190. Second ink tank wall 317 is a side surface facing first ink tank wall 316. Here, the sensor 190 is a photoelectric conversion device 322 in a narrow sense. Then, the processing unit 120 detects the amount of ink in the ink tank 310 based on the output of the sensor 190.

If this is done, the light irradiated from the light source 323 of the sensor unit 320 is reflected by the background plate 330, and the reflected light can reach the photoelectric conversion device 322 via the lens array 325. Therefore, the transmittance of the ink tank 310 can be improved.

Fig. 23 is an example of pixel data in the case where the transmittance of the ink tank 310 is increased as compared with fig. 20 and the background plate 330 is provided inside the ink tank 310. In the region where the ink IK exists, the value of the pixel data is lowered by the absorption of light by the ink IK, which is similar to fig. 20. In addition, in the area where the ink IK is not present, since the reflected light by the background plate 330 is detected as described above, the value of the pixel data becomes sufficiently large. Further, since the transmittance of the ink tank 310 can be increased, the change in the pixel data according to the presence or absence of the ink IK becomes more rapid than that in fig. 20. Since the slope of the graph is large, even if the threshold Th changes within a predetermined range, the change in the ink level position as a result of the determination is suppressed. That is, even if there is a large or small variation in the threshold value setting, the ink level can be detected with high accuracy.

The internal space of the ink tank 310 is divided into a space closer to the-Y direction and a space closer to the + Y direction than the back plate 330, and the space on the side of the inlet 311, i.e., in the + Y direction, is defined as a front chamber, and the space on the side of the outlet 312, i.e., in the-Y direction, is defined as a rear chamber. As described above, since the sensor unit 320 detects the reflected light from the background plate 330, the ink level detected by the sensor unit 320 is the ink level in the rear chamber. If the ink level in the front chamber and the ink level in the rear chamber are different in position, the amount of ink contained in the entire ink tank 310 cannot be accurately estimated even if the ink level in the rear chamber can be detected. That is, in order to achieve appropriate ink amount detection, it is necessary to communicate the front chamber and the rear chamber so that the ink level of the front chamber and the ink level of the rear chamber correspond to each other. At this time, even if the front chamber and the rear chamber communicate vertically above the background plate 330, the ink level in the two spaces does not match as long as the ink level does not exceed the height of the background plate 330. That is, the front chamber and the rear chamber communicate with each other in at least one direction of the left, right, and lower directions of the back plate 330. The left-right direction here is a direction in which the background plate 330 is viewed from the sensor 190 and a direction orthogonal to the vertical direction, and is, for example, the ± X direction.

For example, the front chamber and the rear chamber in the ink tank 310 communicate with each other at least on the left and right sides of the background plate 330 in the lateral direction. In the example of fig. 22, the front chamber and the rear chamber communicate to the right of the background plate 330, since the background plate 330 meets the fourth ink tank wall 319 on the left and does not meet the third ink tank wall 318 on the right. Alternatively, the front and rear chambers may communicate to the left of the background plate 330 by using the background plate 330 that is in contact with the third ink tank wall 318 on the right and is not in contact with the fourth ink tank wall 319 on the left. Since it is difficult to measure an accurate remaining amount of ink because the height of ink differs in the front and rear chambers regardless of the manner in which the front and rear chambers are communicated, the front and rear chambers are communicated in such a manner that the heights of ink are equal in the front and rear chambers.

As described above with reference to fig. 14 and the like, the photoelectric conversion device 322 is specifically a linear image sensor in which a plurality of photoelectric conversion elements are arranged along the vertical direction. Although the photoelectric conversion apparatus 322 as a linear image sensor is a sensor capable of reading a wide range in the up-down direction, the reading range in the left-right direction is narrow. Therefore, the necessity of increasing the length of the background plate 330 in the left-right direction is low. By opening the left or right side of the background plate 330, the front chamber and the rear chamber can be communicated with each other with an efficient structure. Further, the background plate 330 that does not contact both the third ink tank wall 318 and the fourth ink tank wall 319 may be used.

In addition, if a case is considered in which the ink IK smoothly flows between the front chamber and the rear chamber, the front chamber and the rear chamber may be communicated below the background plate 330. However, if consideration is given to suppression of idle running in the print head 107, suppression of printing stop, or the like, it is highly important to detect ink end in detection of the amount of ink. When the background plate 330 is not in contact with the lower wall of the ink tank 310, the ink level near the bottom surface of the ink tank 310 cannot be detected, and detection of ink end may be difficult. Therefore, the lower end of the background plate 330 of the ink tank 310 may also be in contact with the lower wall of the ink tank. The lower wall is specifically an inner wall of a member constituting the bottom surface of the ink tank 310. In this way, a region in which the importance of liquid level detection is high can be set as a detection target.

Fig. 24 is a cross-sectional view showing a positional relationship among the sensor unit 320, the ink tank 310, and the background plate 330. As shown in fig. 24, light from the light source 323 is irradiated onto the ink tank 310 via the light guide 324. Next, a specific light path from the light guide 324 to the photoelectric conversion device 322 and the transmittance of a substance in the path are examined with reference to fig. 24. Further, the position where the background plate 330 is provided is also examined based on the transmittance.

As shown in fig. 24, the printing apparatus according to the present embodiment may include a transmissive plate 340, and the transmissive plate 340 may be disposed between the light source 323 and the sensor 190 and the first ink tank wall 316, and may face the light source 323 and the sensor 190. The transmission plate 340 is, for example, a glass plate, but other members such as plastic may be used.

The transmissive plate 340 is a protective plate for protecting the sensor unit 320 and the lens array 325 in a narrow sense. The distance between the sensor unit 320 and the print head 107 sometimes becomes short depending on the structure of the printing apparatus, so that the sensor unit 320 is contaminated with ink mist. Alternatively, paper dust may adhere to the sensor unit 320 because the printing medium P moves near the sensor unit 320. For example, when smoke or paper dust adheres to the lens array 325, the value of the pixel data of the corresponding portion becomes small, and therefore the accuracy of ink amount detection is reduced. By providing the transmissive plate 340, the lens array 325 can be protected from smoke or paper dust. For example, since the user can wipe off the transmission plate 340 even if smoke or the like adheres thereto, the load of maintenance can be reduced as compared with the cleaning of the lens array 325.

First, in the present embodiment, when the transmittance of the first ink tank wall 316 is Pi and the transmittance of the ink IK is Ti, Pi > Ti. By increasing the transmittance Pi of the first ink tank wall 316, the change in pixel data can be made more severe as described above.

In addition, when the transmittance of the transmissive plate 340 is Gi, Gi ≧ Pi > Ti. As described above, the transmissive plate 340 is a member provided mainly for protecting the sensor unit 320. Considering the accuracy of ink amount detection, it is desirable that the transmission plate 340 has a small influence on the light for ink amount detection. For example, in comparison with the first ink tank wall 316, the attenuation of light by the transmission plate 340 can be reduced by setting Gi ≧ Pi.

As shown in fig. 24, the light emitted from the light guide 324 reaches the background plate 330 after passing through the transmission plate 340, the air layer between the sensor unit 320 and the ink tank 310, the first ink tank wall 316, and the region R between the first ink tank wall 316 and the background plate 330. The reflected light generated by the background plate 330 reaches the lens array 325 after passing through the region R between the background plate 330 and the first ink tank wall 316, the air layer, and the transmission plate 340.

When the ink IK is not present in the region R, the region R becomes an air layer. When the transmittance of the air layer is considered to be 1, the reflected light intensity I' is represented as shown in the following formula (1) by the intensity I of the light irradiated from the light guide 324 and the transmittances of the respective members. R in the following expression (1) is information indicating a ratio of the intensity of the reflected light to the intensity of the light reaching the background plate 330. Here, the reflected light means only light reflected in a direction in which the light can enter the lens array 325, among the light reflected by the background plate 330.

I’＝I×Gi×Pi×r×Pi×Gi…(1)

On the other hand, when the ink IK exists in the region R, the region R is a region filled with the ink IK. When the transmittance of the ink IK filled in the region R is Ti, the reflected light intensity I ″ is represented by the following formula (2). Here, Ti represents an intensity ratio between light incident to the ink IK and light passing through the ink IK to reach the background plate 330. In addition, Ti represents the intensity ratio of the light reflected by the background plate 330 to the light that passes through the ink IK to reach the first ink tank wall 316.

I”＝I×Gi×Pi×Ti×r×Ti×Pi×Gi…(2)

From the above expressions (1) and (2), the following expression (3) is derived.

I”/I’＝Ti²…(3)

That is, in the region where the ink IK is present, the intensity of the reflected light is attenuated to Ti as compared with the region where the ink IK is not present²(< 1). As described above with reference to fig. 20 or 23, in the method of the present embodiment, the ink liquid level is detected based on the difference between pixel data corresponding to the presence or absence of the ink IK. Since the intensity of the reflected light is correlated with the value of the pixel data, when the difference between I ″ and I' is sufficiently large, the difference between the pixel data becomes large, and the amount of ink can be detected with high accuracy.

The longer the distance L between the first ink tank wall 316 and the background plate 330, the longer the optical path for light passing through the ink IK, and the greater the amount of attenuation of the light achieved by the ink IK. In other words, Ti is determined according to the distance L. Therefore, the distance L between the first ink tank wall 316 and the background plate 330 is a distance at which the output of the sensor 190 becomes a predetermined value or less when the light from the light source 323 passes through the ink IK and is reflected by the background plate 330 and is incident on the sensor 190. The predetermined value here is, for example, a threshold value when the processing unit 120 determines that ink is present. In this way, when the ink IK is present, the position of the background plate 330 is determined so that the reflected light intensity is sufficiently reduced by the ink IK, and thereby the accuracy of detecting the amount of ink can be improved.

For example, when the threshold determined to be ink-free by the processing unit 120 is VT1 and the threshold determined to be ink-present is VT2(VT2 is a number satisfying VT2 < VT1) in the process of detecting the amount of ink, Ti may be used as the threshold²< (VT2/VT 1). VT1 and VT2 are, for example, digital data expressed by 8 bits. VT1 is, for example, about 150, and VT1 is, for example, about 50. In this case, the processing unit 120 detects the ink level by setting a threshold Th between 50 and 150, for example. However, the specific values of VT1 and VT2 can implement a wide variety of variations.

In the case of VT 1-150 and VT 2-50, Ti²< 1/3. That is, when the condition that the amount of light is attenuated to less than 1/3 by the ink IK between the ink tank 310 and the background plate 330 is satisfied, the value of the pixel data in the region where the ink IK is present is reduced to such an extent that the pixel data can be clearly distinguished from the pixel data in the region where the ink IK is not present, and therefore, highly accurate liquid level detection can be performed.

When the distance between the first ink tank wall 316 and the background plate 330 is L and the transmittance per unit length of the ink IK is t, t may be^2L< (VT2/VT 1). For example, t is the transmittance per meter of ink IK, and the distance between the first ink tank wall 316 and the background plate 330 is L meters. In the case of passing through the ink IK at a distance twice the unit length, the light is reduced t times and then further reduced t times, and therefore the transmittance of the ink IK at a distance 2 times the unit length is t². As shown in fig. 24, in the optical path from the light guide 324 to the lens array 325, the light moves within the ink IK by at least the length 2L of the reciprocating amount. That is, the light attenuation t is performed by the ink IK^2LAnd (4) doubling. By being based on t^2LDistance L is determined to be < (VT2/VT1) so that the amount of attenuation achieved by ink IK can be sufficiently increased. For example, since t is determined by determining the type of ink IK, the condition that L should satisfy is determined based on t, VT1, and VT 2.

Here, since t < 1, the above expression is a condition for determining the lower limit value of L. That is, by disposing the background plate 330 at a position somewhat distant from the first ink tank wall 316, it is possible to perform liquid level detection with high accuracy. Since the thickness of the ink IK is not present when the distance L is small, even if reflected light having a certain intensity returns from the background plate 330 in a region where the ink IK is present, such a situation can be suppressed.

Further, strictly speaking, the light also moves in the ± X direction, and therefore the moving distance in the ink IK may be longer than 2L. In this case, the light quantity is attenuated to t^2LThe smaller value of the factor, therefore, the condition of increasing the attenuation amount achieved by the ink IK is satisfied.

The surface of the background plate 330 facing the sensor 190 is white, for example. By making the background plate 330 white, the amount of light reflected by the background plate 330 can be increased. In other words, by increasing the reflectance on the background plate 330, the value of the pixel data in the region where the ink IK does not exist is made large. Since the dynamic range can be increased, the accuracy of ink amount detection can be improved. However, the background plate 330 of the present embodiment is not limited to white as long as it is configured to reflect light having a certain intensity. For example, other colors of the background plate 330 may be used.

As shown in fig. 22 and 24, the background plate 330 may have a surface in a direction corresponding to the surface of the sensor 190. Specifically, the background plate 330 has a surface parallel to the surface of the sensor 190. Here, the surface of the sensor 190 is, for example, a surface on which a plurality of photoelectric conversion elements are provided, or a substrate surface of the substrate 321 in a narrow sense. If this is done, the reflected light on the background plate 330 can be made incident appropriately on the photoelectric conversion device 322. In a narrow sense, the reflected light on the background plate 330 can be made to be appropriately incident on the lens array 325.

The permeability of the plurality of wall surfaces of the ink tank 310 may be equal. For example, the ink tank 310 may be a member having a high transmittance such as acrylic as a whole. However, as described above with reference to fig. 24, a case is assumed where light from the light source 323 passes through the first ink tank wall 316 and does not pass through the other wall surface of the ink tank 310 until reaching the photoelectric conversion device 322. Therefore, the first ink tank wall 316 may have a higher transmittance than the left and right wall surfaces of the ink tank 310. By increasing the transmittance of at least the first ink tank wall 316, it is possible to perform ink amount detection with high accuracy even when the transmittance of the third ink tank wall 318 or the fourth ink tank wall 319 is relatively low. Note that the first ink tank wall 316 may be implemented by a transparent film or the like as long as the transmittance of the first ink tank wall 316 is high.

2.3 calibration

The photoelectric conversion device 322 of the present embodiment can also be applied to shading correction that is widely performed in scanners and the like. For example, before shipment of the printing apparatus, a white reference value when reading a subject that becomes a reference for white and a black reference value when reading a subject that becomes a reference for black are acquired. The processing unit 120 performs correction processing using a white reference value and a black reference value for pixel data that is an output of the photoelectric conversion device 322. For example, the processing unit 120 performs a correction process based on the white reference value and the black reference value so that the result of reading the area where the ink IK is not present becomes the maximum value of the digital data and the result of reading the area where the ink IK is present becomes the minimum value. Hereinafter, an example in which the maximum value is 255 and the minimum value is 0 will be described. With this configuration, variations among the plurality of photoelectric conversion elements can be reduced. Further, since the range of the digital data can be sufficiently used, the accuracy of the ink amount detection can be improved.

However, it is known that the light source 323 such as an LED changes the light intensity with time. The illuminance here represents the intensity of light irradiated from the light source 323. For example, even when the same current is supplied from the drive circuit, the output light intensity of the LED varies with the passage of time.

For example, when the light intensity of the light source 323 decreases, the result of reading the region where the ink IK exists decreases to a value lower than 255, for example, about 200. In this case, since the pixel data by the photoelectric conversion device 322 varies in a range of about 0 to 200, there is a possibility that the resolution is lowered and the accuracy of the ink amount detection process is lowered. Further, since the waveform of the pixel data also changes, if the threshold Th used for detecting the amount of ink is not used, an error may occur in the position of the liquid surface. As described above, the shading correction is a correction using information of the shipment time point, and cannot cope with a change over time of the light source 323.

Therefore, in the printing apparatus of the present embodiment, the adjustment of the light intensity of the light source 323 may be performed during calibration. Specifically, the light source 323 is turned on with a light amount based on the result of the sensor 190 detecting the light reflected from the region where the ink IK is not present. Hereinafter, the area used for calibration where the ink IK is not present is referred to as a calibration area CA.

The light amount here is determined based on the illuminance and the lighting time. In this embodiment, since a method using a photoelectric conversion element is assumed, the lighting time indicates a lighting time in a period in which the photoelectric conversion element outputs one pixel signal. The adjustment of the light amount described below may be adjustment of the light intensity or adjustment of the lighting time. The light source 323 may be turned on with a light intensity based on the reading result of the calibration area CA, may be turned on with a time based on the reading result of the calibration area CA, or both may be implemented. For example, when the light source 323 is driven by a pulse signal, the lighting time may be adjusted by adjusting the pulse width of the pulse signal. Specifically, the adjustment of the lighting time is the adjustment of the duty ratio.

As described above, in the ink amount detection process according to the present embodiment, when the difference between the pixel data according to the presence or absence of the ink IK is large, the processing accuracy can be improved. In the following description, in the ink amount detection process, the maximum value of the pixel data acquired using the sensor 190 is DAT1, and the minimum value is DAT 2. DAT1 corresponds to the read results for the areas where ink IK is not present. DAT2 corresponds to the reading of the area where ink IK is present. In the case where DAT1 is large and DAT2 is small, the accuracy of the ink amount detection processing can be improved. For example, in the case of using 8-bit digital data, the range can be fully utilized in the case where DAT1 is 255 and DAT2 is 0.

Since the value of DAT2 is expected to become somewhat small regardless of the light amount of the light source 323, it is particularly important to make the value of DAT1 close to the maximum value of the digital data. The smaller DAT1 is, the narrower the range of pixel data is, the lower the processing accuracy is. Note that, if the light amount of the light source 323 is too large, the DAT1 is likely to be close to 255, but this is not preferable because the pixel data is saturated at a position where the value should be smaller than 255. The light reflected from the alignment area CA where the ink IK is not present is a light amount corresponding to the irradiation light of the light source 323 because it is not necessary to consider the absorption by the ink IK. That is, by performing calibration using the light reflected from the calibration area CA as a reference, the light amount of the light source 323 can be appropriately controlled.

Fig. 25 is an example of pixel data before and after calibration. Before calibration is for example the value of DAT1 before and after 150. In the present embodiment, as shown in fig. 25, control is performed such that DAT1 after calibration is close to 255. This can expand the range of pixel data, and therefore can improve the accuracy of ink amount detection processing and the like.

The processing unit 120 performs a process of adjusting the light amount of the light source 323 so that the result of reading the calibration area CA becomes an adjustment target value. For example, the adjustment target value here is a maximum value of digital data, which is 255 in a narrow sense, as shown in fig. 25. However, as described later, the adjustment target value is changed depending on the situation.

Fig. 26 is an example of the calibration area CA. As shown in fig. 26, the calibration area CA is an area above the ink level in the vertical direction. More specifically, calibration may be performed based on pixel data of a wall surface of the ink tank 310 in the-Y direction, that is, a region above the liquid surface in the first ink tank wall 316.

For example, in a printing apparatus provided with a window portion for visually checking the ink in the ink tank 310, it is conceivable to present the target of the upper limit of the injection amount to the user by providing a scale on the window portion. In this case, if the ink IK is replenished according to the scale, there is a high possibility that the ink IK does not exist in the upper region of the scale.

The calibration area CA may be an area above the opening provided in the top surface of the ink tank 310 in the vertical direction. The opening here is, for example, an inlet 311 of the ink tank 310, but may be a discharge port 312 or another opening such as an air hole. The top surface of the ink tank 310 refers to a wall surface in the + Z direction. In the case where an opening is provided in the top surface, if the liquid surface of the ink IK is located above the opening, the ink IK leaks from the opening. Although the opening may be sealed by a cap or the like depending on the type of the opening, it is not preferable that the liquid surface of the ink IK be located above the opening. Therefore, when there is a region above the opening in the first ink tank wall 316, this region can be used as the calibration region CA.

Fig. 27 shows another example of the calibration area CA. As shown in fig. 27, when the ink tank 310 is empty, a wide range of the first ink tank wall 316 can be used as the calibration area CA. For example, the processing unit 120 detects and reports ink end by the method of the present embodiment, the conventional method of counting the number of times the ink IK is ejected, or both of them. When the user is notified of the ink end, the ink IK is replenished from the bottle or the like to the ink tank 310, and the remaining amount of ink is reset after the replenishment. In such an example, it is assumed that the amount of ink in the ink tank 310 is very small after the notification of ink end and before the reception of the reset operation. Therefore, as shown in fig. 27, a large range of the first ink tank wall 316 can be considered as the calibration area CA.

In both fig. 26 and 27, the calibration area CA is an area that is a part of the first ink tank wall 316. Therefore, the pixel data as the reading result of the calibration area CA corresponds to the above-described DAT 1. In this case, the light source 323 is controlled so that the reading result of the calibration area CA becomes the maximum value of the digital data. For example, the ratio (255/pixel data of the calibration area CA) is used to increase the light amount of the light source 323. As described above, the control of increasing the light amount can be realized by at least one of the control of increasing the light intensity and the control of increasing the duty ratio.

Further, there is also a light source with a luminous intensity that increases with time, depending on the light source 323. When calibration is performed in advance such that DAT1 becomes 255, light having a larger light amount than the light amount corresponding to 255 returns from the calibration area CA when the light intensity increases with time. Actually, a range of analog voltages that can be converted is set in the a/D conversion circuit of the AFE circuit 130. When the illuminance becomes high with time, the output signal OS as the reading result of the calibration area CA becomes a voltage value larger than the upper limit value Vmax of the conversion range, and therefore, is clipped to the upper limit value Vmax, and the value of the pixel data becomes 255. However, in a region where the original pixel data is not saturated, the pixel data is larger than a desired value, and therefore, in this case, the accuracy of ink amount detection is also lowered.

For example, the processing unit 120 may perform control to temporarily decrease the light amount when the reading result of the calibration area is 255. By controlling the light quantity to decrease to a level at which the reading result of the calibration area CA is not saturated and then to increase to a level at which the reading result of the calibration area CA approaches 255, appropriate calibration can be achieved. As described above, since the adjustment target value becomes 255 when the reading result of the calibration area CA corresponds to DAT1, the setting of the adjustment target value and the calibration process can be easily performed.

Fig. 28 is another example of the calibration area CA. As shown in fig. 28, the calibration area CA is not defined by the first ink tank wall 316. For example, the region where the ink IK does not exist may be a region provided laterally outside the ink tank 310. In this way, since it is ensured that the ink IK does not exist in the alignment area CA, the influence of the ink IK on the alignment can be suppressed.

For example, in the printing apparatus, when the ink tank 310 and the sensor unit 320 move relative to each other, the reflecting member 350 may be provided on the lateral outer side of the ink tank 310. The calibration area CA is an area included in the reflection part 350. For example, the printing apparatus is a carriage-mounted type apparatus, the sensor unit 320 is provided outside the carriage 106, and the reflecting member 350 is mounted on the carriage 106. The reflecting member 350 is provided in the + X direction or the-X direction of the ink tank 310, and the carriage 106 reciprocates in the X-axis direction with respect to the sensor unit 320. In this way, the sensor unit 320 for detecting the amount of ink can be used for calibration.

For example, the reflecting member 350 is made of the same material as the ink tank 310. In a narrow sense, the reflective member 350 is the same member as the first ink tank wall 316. If this is done, the reading result of the calibration area CA is equivalent to DAT1 as in the examples of fig. 26 and 27. Therefore, the reading result of the calibration area CA may be set to be close to 255, and the setting of the adjustment target value is easy.

However, the calibration in the present embodiment is not limited to the example in which the read result of the calibration area CA corresponds to DAT 1. In other words, the adjustment target value is not limited to the maximum value of the digital data.

Fig. 29 is another example of the calibration area CA. As shown in fig. 29, the calibration area CA may also be an area of an end of the ink tank 310 in the horizontal direction. Here, the horizontal direction is the ± X direction, and the region of the end in the horizontal direction is the end in the + X direction or the end in the-X direction in the plan view of the ink tank 310 viewed from the sensor unit 320.

More specifically, the end portion region is a region corresponding to the thickness of the side wall of the ink tank 310. The side wall here refers to the third ink tank wall 318 as a wall in the-X direction or the fourth ink tank wall 319 as a wall in the + X direction. Specifically, the calibration area CA may be an area where the first ink tank wall 316 and the third ink tank wall 318 overlap or an area where the first ink tank wall 316 and the fourth ink tank wall 319 overlap, in a plan view of the ink tank 310 from the sensor unit 320. Alternatively, the calibration area CA may be an area where the third ink tank wall 318 or the fourth ink tank wall 319 is exposed.

The ink IK is stored in the ink tank 310 in an area surrounded by the inner surfaces of the first to fourth ink tank walls 316 to 319, respectively. Since the calibration area CA shown in fig. 29 does not contain the ink IK, high-precision calibration can be performed. Further, unlike the example of fig. 28, it is not necessary to provide a separate calibration-dedicated component.

However, the thickness of the first ink tank wall 316 in the ± Y direction is relatively thin, whereas the thickness of the calibration area CA in fig. 29 in the ± Y direction is relatively thick. When the ink tank 310 is a milky member having a relatively low transmittance, a portion having a large thickness in the ± Y direction is white and strong, and thus the value of the pixel data as the read result becomes large.

In this case, the pixel data as the read result of the calibration area CA is larger than DAT 1. Therefore, even if calibration is performed in which the read result of the calibration area CA becomes 255, the DAT1 is smaller than 255.

The relationship between the reading of the calibration area CA and DAT1 is known from design point of view. The relationship here refers to, for example, a ratio of numerical values as a result of reading. Therefore, for example, X satisfying the condition that DAT1 becomes 255 if the reading result of the calibration area CA becomes X (X ≠ 255) can be determined in advance. Therefore, the processing unit 120 acquires X as an adjustment target value in advance, and adjusts the light amount of the light source 323 so that the reading result of the calibration area CA becomes the adjustment target value.

However, in the example shown in fig. 29, a case is assumed where X > 255. For example, by setting X to 300, that is, by setting the value of the read result of the calibration area CA to 300, DAT1 can be made close to 255. However, when the a/D conversion circuit of the AFE circuit 130 performs 8-bit a/D conversion, the digital value of 300 cannot be expressed. For example, when Vmax is an upper limit voltage value to be subjected to a/D conversion, a voltage value equal to or greater than Vmax is limited to Vmax, and a/D conversion is performed to output 255.

For example, the a/D conversion circuit may be configured to perform a/D conversion with a larger number of bits than in the case of performing the ink amount detection processing. For example, the a/D conversion circuit may be a 9-bit a/D converter that converts Vmax into 255 and can output a digital value in a range of 0 to 511. In this case, the analog voltage corresponding to 2 times Vmax is not clipped. Therefore, it is possible to perform control of setting a digital value larger than 255 as an adjustment target value and bringing the value of the result of reading the calibration area CA close to the adjustment target value.

However, the calibration according to the present embodiment is not limited to this. For example, in an a/D conversion circuit, the voltage range to be subjected to a/D conversion may be a variable range. By making the upper limit voltage value larger than Vmax, appropriate calibration can be performed without clipping the read result of the calibration area CA.

In the configuration using the reflecting member 350 shown in fig. 28, the reflecting member 350 may be made of a material different from that of the ink tank 310. In this case, the adjustment target value may be determined in advance based on the relationship between the reflectance of the reflective member 350 and the reflectance of the ink tank 310. The adjustment target value may be a larger value or a smaller value than the maximum value of the digital data as described above. The processing unit 120 adjusts the light amount of the light source 323 so that the result of reading the calibration area CA becomes the adjustment target value.

The calibration area CA may be a portion of the wall of the ink tank 310 that is thicker than other portions. For example, the calibration area CA shown in fig. 29 is also a wall of the ink tank 310, and is a thicker portion than other portions, for example, a portion that does not overlap with the third ink tank wall 318 in the first ink tank wall 316. However, the calibration area CA is not limited thereto.

Fig. 30 shows another example of the calibration area CA. For example, the first ink tank wall 316 of the ink tank 310 may also be different in thickness depending on the position on the Z-axis as shown in fig. 30. In the example of fig. 30, the thickness t1 of the region whose Z-coordinate value is a given threshold value or less, and the thickness t2 of the region whose Z-coordinate value is greater than the threshold value satisfy t2 > t 1. The calibration area CA is set on a portion of the first ink tank wall 316 where the thickness satisfies t 2. In this case, there is a possibility that the ink IK exists on the back side of the calibration area CA, specifically, on the + Y direction side when viewed from the sensor unit 320. However, when the transmittance of the ink tank 310 is low to some extent, scattering and absorption inside the first ink tank wall 316 become large. Therefore, since the intensity of the reflected light on the first ink tank wall 316 becomes sufficiently stronger than the intensity of the light reaching the ink IK, the influence on the alignment by the ink IK can be suppressed. That is, the area where the ink IK is not present in the present embodiment is not limited to the area where the ink IK is not present at all in the + Y direction from the sensor unit 320 to the ink tank 310, and includes an area where even if sufficient light is present on the back side, the ink IK is not reached.

The processing unit 120 may adjust the output of the sensor 190 using a gain obtained based on the result of reading the calibration area CA. If this is done, the range of pixel data can be adjusted using the gain versus size of the pixel data in addition to the control of the light source 323. The light amount adjustment of the light source 323 is more advantageous than the gain adjustment in that the resolution of the pixel data is increased or the amplification of noise is suppressed. However, when the range is not fully expanded by the adjustment using only the light source 323, the gain adjustment is effective. For example, the result of reading the calibration area CA may be a value obtained by applying a gain to the output of the sensor 190. That is, the light amount and the gain are adjusted so that the value after the gain acts becomes the adjustment target value. By obtaining the output of the sensor 190 by using the adjusted light amount and causing the adjusted gain to act on the output, DAT1 can be made close to the maximum value of the digital data.

Fig. 31 is a flowchart for explaining the calibration. The processing of fig. 31 is executed, for example, when the printing apparatus is started up. When this process starts, the warm-up of the photoelectric conversion apparatus 322 is first performed (step S201). Next, the processing unit 120 sets the light amount and the gain to initial values (step S202). In addition, an example in which the light amount is adjusted by the lighting time of the light source 323 will be described below.

Next, the processing unit 120 controls the sensor unit 320 to acquire the reading result of the calibration area CA by using the light amount and the gain set in step S202 (step S203). The processing unit 120 controls the lighting time so that the result obtained in step S203 becomes the adjustment target value (step S204).

When the read result reaches the adjustment target value by the adjustment of the lighting time, the processing unit 120 ends the calibration and executes the ink amount detection processing and the like using the adjusted lighting time.

On the other hand, when the read result does not reach the adjustment target value in the adjustment of the lighting time, the processing unit 120 repeatedly performs the readjustment of the lighting time (step S204) and the adjustment of the gain (step S205) until the read result reaches the adjustment target value. The adjustment of the lighting time and the adjustment of the gain are not limited to the alternate embodiment. For example, the lighting time may be preferentially adjusted, and the gain may be adjusted when the lighting time does not reach the adjustment target value.

3. Ink type judging process

In the present embodiment, the processing unit 120 may determine the ink type of the ink IK in the ink tank 310 based on the output of the sensor 190.

3.1 overview of ink type determination processing

As described above with reference to fig. 2 and 3, the electronic device 10 may include a plurality of ink tanks 310 each filled with different types of ink IK. In this case, the user may erroneously fill the ink IKa to be filled in the ink tank 310a into another ink tank 310 such as the ink tank 310 b. Even if the electronic device 10 is a monochrome printing apparatus having one ink tank 310, if the user uses printing apparatuses of different models together, the ink IK used in the other printing apparatus may be erroneously filled. Further, even when the user uses only one monochrome printing apparatus, since a large amount of ink IK that differs depending on the model is distributed in the market, the possibility that the user erroneously purchases and fills ink for a different model cannot be denied.

If the ink tank 310 to be filled with the yellow ink is filled with the magenta ink, the hue of the printing result will be greatly deviated from the desired hue. That is, in order to perform appropriate printing, it is necessary to appropriately detect misuse of the color of the ink IK. Therefore, the processing unit 120 determines the ink color as the ink type.

The sensor 190 of the present embodiment detects light of a plurality of colors incident from the ink tank 310 while the light source 323 emits light. The processing unit 120 estimates the type of ink in the ink tank 310 based on the output of the sensor 190 at the position corresponding to the meniscus portion of the ink IK.

The light of the plurality of colors in the present embodiment may be R light corresponding to a red wavelength band, G light corresponding to a green wavelength band, and B light corresponding to a blue wavelength band. A signal corresponding to R light is an R signal, a signal corresponding to G light is a G signal, and a signal corresponding to B light is a B signal.

For example, the printing apparatus includes a red LED323R, a green LED323G, and a blue LED323B, and the photoelectric conversion device 322 outputs an R signal, a G signal, and a B signal based on light emission of the respective LEDs. Alternatively, the printing apparatus may include a white light source and a plurality of filters having different pass ranges, and the photoelectric conversion device 322 may output the R signal, the G signal, and the B signal based on the transmitted light of the filters. However, the plurality of types of light in the present embodiment is not limited to RGB, and any one of the types of light may be omitted or light in other wavelength bands may be added.

Fig. 32 is a diagram illustrating a meniscus portion and a reading result of the meniscus portion. The meniscus represents the curvature of the ink level created by the interaction of the ink tank 310 and the ink IK. The meniscus portion refers to a portion where the ink surface is curved. For example, the range shown in B1 of fig. 32 is a meniscus portion. As shown in fig. 32, the thickness of the ink IK is thinner in the meniscus portion than in a region vertically below the meniscus portion. Specifically, the length of the region where the ink IK exists is short in the ± Y direction. Therefore, the degree of light absorption by the ink IK becomes relatively low.

The ink IK easily absorbs light, and particularly, the ink IK of the dye absorbs light to a large extent. Therefore, when the thickness of the ink IK in the observation direction is thick to some extent, a region where the ink IK is present is observed to have a color close to black. In the case where the signal from the ink tank 310 is detected by the photoelectric conversion device 322, the observation direction refers to the ± Y direction. Therefore, the ink color is close to black regardless of the ink color at the lower side than the meniscus portion, and it is often difficult to determine the ink type.

B2 of fig. 32 represents the reading result by the sensor 190. The read result refers to, for example, image data formed by the output of the photoelectric conversion device 322. As shown in fig. 32, the reading result is close to black at the lower side and close to white at the upper side than the meniscus portion. Although fig. 32 shows a view in which the meniscus portion is gradually changed from black to white for the sake of convenience of explanation, when the actual ink IK is targeted, a color unique to the ink IK appears in a portion having a small density. For example, the region of the image data corresponding to the meniscus portion has a hue such as cyan, magenta, yellow, etc., corresponding to the ink color.

Therefore, the processing unit 120 may estimate the ink type based on the color of the reading result of the meniscus portion. For example, the sensor 190 obtains the R signal, the G signal, and the B signal as the read results. Then, the processing unit 120 determines a color based on at least one of the R pixel value, the G pixel value, and the B pixel value. As described above, since the portion other than the meniscus portion is close to white or black, the chromaticity is very small. Therefore, the processing unit 120 determines, for example, a region having a chromaticity equal to or higher than a predetermined threshold value as the meniscus portion.

For example, when the color of the reading result of the meniscus portion is blue, the processing unit 120 determines that the color of the ink IK is cyan or black. When the color of the reading result of the meniscus portion is red, the processing unit 120 determines that the color of the ink IK is magenta or yellow. In this way, the ink color can be discriminated based on which component of RGB has a high degree of contribution. In addition, when it is necessary to recognize cyan and black and to recognize magenta and yellow, different color components may be compared. The processing unit 120 may calculate a hue based on each pixel value of RGB, for example, and determine an ink color based on the value of the hue.

Alternatively, the determination of the meniscus portion and the determination of the ink color may be performed based on the waveforms of the R signal, the G signal, and the B signal. Details will be described later with reference to fig. 33 and the like.

Further, since the ink IK of a color clearly distinguishable from black is present in a region where the ink IK is thick, such as a magenta ink containing a pigment, a yellow ink containing a pigment, and the like, it is possible to use a read result of a region below the meniscus portion when such an ink IK is recognized as another ink IK.

3.2 ink color discrimination for dye inks

The processing unit 120 may discriminate the color of the dye ink as the ink type. Dye inks have a higher degree of light absorption than pigment inks. Therefore, when the ink IK has a thickness, the ink area is close to black regardless of the ink color, and thus it is difficult to determine the ink color. In this regard, by using the meniscus portion for the judgment as described above, the ink color judgment can be appropriately performed.

Fig. 33 is a graph showing the results of reading the cyan ink, magenta ink, yellow ink, and black ink of the dyes. As shown in fig. 33, each read result includes an R signal, a G signal, and a B signal. The horizontal axis of each graph in fig. 33 represents the position of the photoelectric conversion element, and the vertical axis represents the signal value. The signal value is, for example, 8-bit digital data. Although the pixel value of the ink non-detection area is about 150 to 200 here, the value may be corrected to about 255 by performing calibration. Here, the height of the ink level differs for each ink IK.

As described above, the absorption of light of the dye ink is large, and the reflected light from the portion where the ink IK exists at a sufficient thickness is very small. Therefore, the processing unit 120 determines an area where the RGB signals have values close to the lowest value as an area where the ink IK exists. In the meniscus portion, since the thickness of the ink IK becomes thin as described above, a color component corresponding to the ink color is observed. For example, as shown in C1 to C3 in fig. 33, the rising edges of the RGB signals are detected. The rising edge here indicates a case where the signal value starts to increase from the minimum value or a value in the vicinity of the minimum value in a direction from vertically below to above. In the case of the cyan ink of the dye, C1 is the rising edge of the B signal, C2 is the rising edge of the G signal, and C3 is the rising edge of the R signal.

The processing unit 120 sets a signal of a range including a rising edge of the reading result as the reading result of the meniscus portion. For example, the processing unit 120 determines the ink type based on a signal including the range indicated by C4 in the reading result for the dye cyan ink.

For example, the processing unit 120 may estimate the ink type based on the rising edge pattern of the signals of the plurality of color components corresponding to the plurality of types of light having different wavelength bands in the direction from the presence of ink to the absence of ink in the meniscus portion. The direction from the presence of ink to the absence of ink means, for example, a direction from vertically below to above, and is narrowly defined as the + Z direction. The rising edge is a point at which the signal value starts to rise at the position on the upper side of the lower wall of the ink tank 310 as described above, and therefore, there is an advantage that detection is easy.

The specific rising edge sequence is shown in fig. 33. For example, when the rising order of the meniscus portion is the order of the B signal, G signal, and R signal, the processing unit 120 determines that the color of the ink IK is cyan or black. When the rising edge sequence at the meniscus portion is the sequence of the R signal, the B signal, and the G signal, the processing unit 120 determines that the color of the ink IK is magenta. When the rising edge sequence of the meniscus portion is the sequence of the R signal, G signal, and B signal, the processing unit 120 determines that the color of the ink IK is yellow.

In addition, the cyan ink herein includes light cyan ink and the like of cyan color. Also, among the magenta inks, light magenta ink, red ink, and the like are included. Among the yellow inks, light yellow inks and the like are included. Among the black inks, light black inks and the like of a color similar to black are included.

In this manner, the meniscus portion can be used to determine the ink color of the dye ink. Further, if the difference between the signal waveforms of the respective ink colors is made clear or the position of the rising edge is determined with high accuracy, it is desirable that the transmittance of the ink tank 310 is high. For example, when the ink type determination process is performed using the reading result of the meniscus portion, the ink tank 310 may include the background plate 330 inside as shown in fig. 22.

As described above, the rising edge sequence of the signals for the cyan ink and the black ink are the same. In the present embodiment, the cyan ink and the black ink may not be recognized. In this case, it is also possible to identify the three ink types of cyan, black, magenta, and yellow. Therefore, for example, it is possible to detect that the ink IK of the wrong color is filled in the given ink tank 310.

The processing unit 120 may recognize cyan ink and black ink based on a difference between rising edge positions of the signals. The difference between the rising edge positions represents, for example, the distance on the Z axis between the rising edge position of the B signal and the rising edge position of the R signal. As shown in fig. 33, the difference in the rising edge position in the cyan ink is C4 and is larger than C5, which is the difference in the rising edge position in the black ink. Therefore, the processing unit 120 can determine whether the ink IK to be processed is cyan ink or black ink by performing comparison processing between the difference in the rising edge positions and a predetermined threshold value.

The judgment processing of the ink type using the reading result of the meniscus portion is not limited to the method using the ascending order. For example, when the signal intensity at the meniscus portion is B signal > G signal > R signal, the processing unit 120 determines that the color of the ink IK is cyan or black. When the signal intensity at the meniscus portion is R signal > B signal > G signal, the processing unit 120 determines that the color of the ink IK is magenta. When the signal intensity at the meniscus portion is R signal > G signal > B signal, the processing unit 120 determines that the color of the ink IK is yellow.

The intensity of each signal is specifically the value of the digital data after a/D conversion. However, as shown in fig. 33, the signals of the plurality of colors sequentially rise in the meniscus portion. Therefore, when two or more signals are before the rising edge, the signal intensities cannot be compared appropriately. Therefore, the signal intensity in the meniscus portion may also be, for example, the signal intensity at a position after the last signal rising edge in the + Z direction. When cyan ink is used as the target, the rising edge position of the last signal is C3 which is the rising edge position of the R signal. The intensity of the B signal at the position corresponding to C3 was C6, the intensity of the G signal was C7, and the intensity of the R signal was 0. Therefore, the signal intensity of the cyan ink becomes B signal > G signal > R signal. However, since the intensity comparison can be performed if all the signals rise, the ink type may be determined by the signal intensity at the position closer to the + Z direction than C3. For example, the processing unit 120 may determine the end point on the + Z side of the meniscus portion by using the condition that the chromaticity is equal to or greater than the predetermined threshold value, as described above. The processing unit 120 may obtain the signal intensity of each signal at an arbitrary position between the point where all signals rise and the end point on the + Z side.

3.3 ink color discrimination for pigmented inks

The processing unit 120 may also discriminate the color of the pigment ink as the ink type. Pigment inks absorb light to a lesser extent than dye inks. Therefore, for example, when the background plate 330 is provided and the ink tank 310 having a relatively high transmittance is used, the intensity of the reflected light increases to some extent even in the region where the ink IK is present.

Fig. 34 is a graph showing the results of reading cyan ink, magenta ink, yellow ink, and black ink of pigments, respectively. As in fig. 33, each read result includes an R signal, a G signal, and a B signal. In addition, the horizontal axis of each graph represents the position of the photoelectric conversion element, and the vertical axis represents the signal value.

The black ink and the cyan ink showed the same tendency as the dye ink. That is, the meniscus portion rises in the order of the B signal, the G signal, and the R signal. In addition, the difference in the rising edge position between signals of cyan ink is larger than that of black ink.

As shown in fig. 34, even in the region where the ink IK is present, the R signal of the pigment magenta ink has a sufficiently larger value than the minimum value. For example, when 8-bit digital data is used, the signal value in the region of the R signal where the ink IK is present is sufficiently large, such as about 100. In the R signal, since the value does not increase from the vicinity of the minimum value in the + Z direction, a rising edge is not detected. On the other hand, the values of the B signal and the G signal are sufficiently small in the region where the ink IK exists, and a rising edge is detected in the meniscus portion in the order of the B signal and the G signal.

As shown in fig. 34, even in the region where the ink IK is present, the R signal and the G signal of the pigment yellow ink are sufficiently larger than the minimum values. For example, in the region where the ink IK is present, the signal value of the R signal is about 200, and the signal value of the G signal is about 100. Therefore, no rising edge is detected for the R signal and the G signal. On the other hand, in the B signal, in the region where the ink IK exists, the value is sufficiently small, and thus a rising edge is detected in the meniscus portion.

The processing unit 120 may determine the ink type based on the signal intensity at the meniscus portion. When the signal intensity at the meniscus portion is B signal > G signal > R signal, the processing unit 120 determines that the ink IK is cyan or black. When the signal intensity at the meniscus portion is R signal > B signal > G signal, the processing unit 120 determines that the color of the ink IK is magenta. When the signal intensity at the meniscus portion is R signal > G signal > B signal, the processing unit 120 determines that the color of the ink IK is yellow.

As shown in fig. 34, since the rising edge of the R signal is not detected in the magenta ink of the pigment, it is determined that the rising edge position of the G signal is the position after the last signal in the + Z direction rises. In the yellow ink of the pigment, since the rising edges of the R signal and the G signal are not detected, it is determined that the rising edge position of the B signal is the position after the last signal in the + Z direction rises. In this manner, the color of the pigment ink can be determined by using the reading result of the meniscus portion. In this case, since the same judgment standard as that of the dye ink can be used, the processing can be made common. However, the pigment magenta ink or the pigment yellow ink can be recognized based on the presence or absence of the rising edge of each signal, and the ink color determination process for the pigment ink is not limited to the above.

3.4 relationship to ink quantity detection

The processing unit 120 performs a process of estimating the type of ink and a process of detecting the amount of ink based on the output of the sensor 190 at a position corresponding to the meniscus portion of the ink IK. In this manner, the type of ink can be determined by the sensor unit 320 for detecting the amount of ink. Although the meniscus portion is useful for determining the type of ink as described above, the meniscus portion is also useful for detecting the amount of ink because it corresponds to the ink surface. That is, by appropriately specifying the meniscus portion in the reading result, it is possible to appropriately perform both the processing of the ink amount detection and the processing of the ink type determination.

The processing unit 120 may detect the amount of ink based on a detection result of the color of the ink surface detected at a rising edge start position at the time of the signal value rising from the presence of ink to the absence of ink, among detection results of the sensors 190 corresponding to the respective colors of the plurality of colors.

As described above, in the case of using a configuration capable of detecting signals of a plurality of colors, for example, a configuration capable of acquiring signals of RGB, the ink amount detection may be performed by using any one of the signals, or may be performed by combining a plurality of signals. However, as described above, in the meniscus portion, the respective signals rise in the order corresponding to the ink colors. Therefore, depending on which signal is used for detecting the amount of ink, the position of the liquid surface as a result of the detection may change. Since the ink IK is present in the meniscus portion, although thin, the rise of the signal in the wavelength band that is easily absorbed by the ink IK is slow. In other words, when the thickness of the ink IK in the + Z direction becomes thinner from the region where the ink IK is sufficiently present, a signal having high sensitivity to the change is suitable for the ink amount detection.

The rising edge start position is a position where the ink level is first raised in a direction from the presence of ink to the absence of ink, and the detection of the ink level means that the signal value increases from the minimum value. For example, the dye cyan ink and the dye black ink are detected as ink amounts based on the B signal. The amount of ink was detected based on the R signal for the dye magenta ink and the dye yellow ink. For pigment inks, the rising edge can be detected, and the earliest rising signal becomes the B signal for any color. Therefore, the pigment ink is detected as an ink amount based on the B signal.

The method of the present embodiment may be applied to a printing apparatus that detects the amount of ink based on the detection result of the color of the ink surface detected at the rising edge start position and does not perform the determination processing of the ink type.

4. Compound machine

The electronic device 10 according to the present embodiment may be a multifunction peripheral having a printing function and a scanning function. Fig. 35 is a perspective view showing a state in which the housing portion 201 of the scanner unit 200 is rotated with respect to the printer unit 100 in the electronic apparatus 10 of fig. 1. In the state shown in fig. 35, the document table 202 is exposed. The user instructs the operation unit 160 to execute scanning after a document to be read is set on the document table 202. The scanner unit 200 reads an image of a document by performing a reading process while moving an image reading unit, not shown, in response to an instruction operation by a user. The scanner unit 200 is not limited to a flathead scanner. For example, the scanner unit 200 may be a scanner having an ADF (Auto Document Feeder), not shown. The electronic apparatus 10 may be an apparatus having both a flathead scanner and an ADF scanner.

The electronic device 10 includes an image reading portion including a first sensor module, an ink tank 310, a print head 107, a second sensor module, and a processing portion 120. The image reading unit reads a document by a first sensor module including m (an integer equal to or greater than 2) linear image sensor chips. The second sensor module includes n (n is an integer of 1 or more and n < m) linear image sensor chips, and detects light incident from the ink tank 310. The processing unit 120 detects the amount of ink in the ink tank based on the output of the second sensor module. The first sensor module is a sensor module used in scanning of an image in the scanner unit 200, and the second sensor module is a sensor module used in an ink amount detection process in the ink tank unit 300.

The first sensor module and the second sensor module each include a linear image sensor chip. A specific structure of the linear image sensor chip is the same as the photoelectric conversion apparatus 322 realized in the above-described manner, and a chip in which a plurality of photoelectric conversion elements are arranged in a predetermined direction is arranged. Since the line image sensor used in image reading and the line image sensor used in the ink amount detection process can be shared, the electronic apparatus 10 can be efficiently manufactured. Of course, the line image sensor used for image reading and the line image sensor used for the ink amount detection process may be respectively provided as separate line image sensors having been specialized.

However, the first sensor module needs to have a length corresponding to the size of the original to be read. Since one line image sensor chip has a length of, for example, about 20mm, the first sensor module needs to include at least two or more line image sensor chips. In contrast, the second sensor module has a length corresponding to the target range of ink amount detection. Although the target range for ink amount detection can be variously modified, it is generally shorter than image reading. That is, as described above, m is an integer of 2 or more, n is an integer of 1 or more, and m > n. In this manner, the number of the linear image sensor chips can be appropriately set according to the application.

In addition, the difference between the first sensor module and the second sensor module is not limited to the number of the linear image sensor chips. The length directions of the m linear image sensor chips of the first sensor module are arranged along the horizontal direction. The n linear image sensor chips of the second sensor module are arranged such that the longitudinal direction thereof is along the vertical direction. Since the second sensor module needs to detect the liquid level of the ink IK as described above, the longitudinal direction is the vertical direction.

On the other hand, if the case of reading an image of a document is considered, it is necessary to set the longitudinal direction of the first sensor module to the horizontal direction. This is because, when the longitudinal direction of the first sensor module is set to the vertical direction, it is difficult to stably set the document on the document table 202 or to stabilize the document posture when the document is conveyed by the ADF. By setting the longitudinal direction of the linear image sensor chip according to the application, the ink amount detection process and the image reading can be appropriately performed.

In addition, the first sensor module operates at a first operating frequency and the second sensor module operates at a second operating frequency that is lower than the first operating frequency. In image reading, it is necessary to successively acquire signals corresponding to a large number of pixels and perform a/D conversion processing, correction processing, and the like on the signals to form image data. Therefore, it is preferable that the reading by the first sensor module is performed at high speed. On the other hand, even if a certain amount of time is still required before the amount of ink is detected in the case where the number of photoelectric conversion elements is small, the detection of the amount of ink is difficult to be problematic. By setting the operating frequency for each sensor module, each sensor module can be operated at an appropriate speed.

It will be apparent to those skilled in the art that while the present embodiment has been described in detail, many modifications can be made without substantially departing from the novel concept and effects of the present invention. Therefore, such modifications are also all included in the scope of the present disclosure. For example, in the specification or the drawings, a term described at least once together with a different term having a broader meaning or the same meaning can be replaced with the different term at any position in the specification or the drawings. All combinations of the present embodiment and the modifications are also included in the scope of the present disclosure. The configurations, operations, and the like of the electronic device, the printer unit, the scanner unit, the ink tank unit, and the like are not limited to those described in the present embodiment, and various modifications can be made.

For example, the photoelectric conversion device may be arranged in a horizontal direction or obliquely from the horizontal direction. In this case, by arranging the plurality of line image sensors in the vertical direction or by relatively moving the plurality of line image sensors in the vertical direction with respect to the ink tank, information equivalent to that obtained when the line image sensors are arranged in the vertical direction can be obtained. Further, the photoelectric conversion device may also be one or more area image sensors. By adopting such a configuration, a configuration in which one image sensor spans a plurality of ink tanks can also be adopted.

Further, for example, the photoelectric conversion device and the ink tanks may be prepared and fixed in a one-to-one manner, but one photoelectric conversion device and a plurality of ink tanks may be moved relative to each other. In the case of performing the relative movement, the photoelectric conversion device may be mounted on the carriage and the ink tank may be provided outside the carriage, or conversely, the ink tank may be mounted on the carriage and the photoelectric conversion device may be provided outside the carriage.

Description of the symbols

10 … an electronic device; 100 … printer unit; 101 … operating panel; 102 … outer shell portion; 104 … front face mask; 105 … tubes; 106 … carriage; 107 … print head; 108 … paper feed motor; 109 … carriage motor; 110 … paper feed roller; 111 … second substrate; 120 … processing part; 130 … AFE circuitry; 140 … storage section; 150 … display part; 160 … an operating part; 170 … external I/F section; a 190 … sensor; 200 … scanner unit; 201 … a housing portion; 202 … manuscript table; 300 … ink tank unit; 301 … outer shell portion; a 302 … cover portion; 303 … hinge portion; 310. 310a, 310b, 310c, 310d, 310e … ink tanks; 311 … injection port; 312 … discharge port; 313 … second discharge port; 314 … ink flow path; 315 … primary container; 316 … first ink tank wall; 317 … a second ink tank wall; 318 … third ink tank wall; 319 … fourth ink tank wall; 320 … sensor unit; 321 … a substrate; 322 … photoelectric conversion device; 3222 … control circuitry; 3223 … voltage boost circuit; 3224 … pixel driving circuit; 3225 … pixel portion; 3226 … CDS circuitry; 3227 … sample-and-hold circuit; 3228 … output circuit; 323 … light source; 323B … blue LED; 323G … green LED; 323R … red LED; 324 … light guide body; 325 … lens array; 326 … outer shell; 327 … opening part; 328 … a second opening; 329 … light barrier walls; 330 … background board; 340 … through the plate; 350 … reflective member; CDSC, CPC, DRC … control signals; a CLK … clock signal; drv, DrvB, DrvG, DrvR … drive signals; EN _ I, EN _ O, EN 1-ENn … chip enable signals; HD … main scan axis; VD … sub scan axis; IK. Ika, IKb, IKC, IKd, IKE … inks; OP1, OP2 … output terminals; OS … output signal; p … print media; RS … reflective surface; RST … reset signal; SEL … pixel select signals; SMP … samples the signal; tx … transmits control signals; VDD, VSS … supply voltages; VDP, VSP … power terminals; VREF … reference voltage; VRP … reference voltage supply terminal.