1. An image forming apparatus includes:

a photosensitive drum;

an exposure device that exposes the photosensitive drum based on image data;

a developing device that forms a toner image on the photoconductive drum with toner supplied from a toner cartridge;

a toner replenishment motor configured to supply toner from the toner cartridge to the developing device; and

and a processor for calculating a toner remaining amount in the toner cartridge based on a toner replenishment rate calculated based on a pixel count value of the image data and a driving time of the toner replenishment motor, a preset reference replenishment rate, and the driving time of the toner replenishment motor.

2. The image forming apparatus according to claim 1,

the processor calculates the toner remaining amount based on a driving time of the toner replenishment motor,

the processor corrects the toner remaining amount based on a reference replenishment rate and the toner replenishment rate.

3. The image forming apparatus according to claim 2,

the processor subtracts a correction value from the toner remaining amount when the toner replenishment rate is greater than the reference replenishment rate.

4. The image forming apparatus according to claim 3,

the processor determines the correction value based on a difference between the toner replenishment rate and the reference replenishment rate.

5. The image forming apparatus according to claim 2,

the processor adds a correction value to the toner remaining amount when the toner replenishment rate is smaller than the reference replenishment rate.

6. The image forming apparatus according to claim 5,

the processor determines the correction value based on a difference between the toner replenishment rate and the reference replenishment rate.

7. The image forming apparatus according to claim 2,

when the toner remaining amount is less than a predetermined threshold, the processor does not correct the toner remaining amount.

8. The image forming apparatus according to claim 1,

the processor detects near-end when the remaining toner amount is less than a preset near-end threshold.

9. A method of controlling an image forming apparatus, wherein,

the image forming apparatus includes: a photosensitive drum; an exposure device that exposes the photosensitive drum based on image data; a developing device that forms a toner image on the photoconductive drum with toner supplied from a toner cartridge; a toner replenishment motor configured to supply toner from the toner cartridge to the developing device; and a processor for processing the received data,

the processor calculates a toner remaining amount in the toner cartridge based on a toner replenishment rate calculated based on a pixel count value of the image data and a driving time of the toner replenishment motor, a preset reference replenishment rate, and the driving time of the toner replenishment motor.

10. An image forming apparatus includes:

a photosensitive drum;

an exposure device that exposes the photosensitive drum based on image data;

a developing device that forms a toner image on the photoconductive drum with toner supplied from a toner cartridge;

a toner replenishment motor configured to supply toner from the toner cartridge to the developing device; and

and a processor for calculating a toner remaining amount in the toner cartridge based on a toner replenishment rate calculated based on a pixel count value of the image data and a driving time of the toner replenishment motor, a preset reference replenishment rate, and a pixel count value.

11. The image forming apparatus according to claim 10,

the processor calculates the toner remaining amount based on the pixel count value,

the processor corrects the toner remaining amount based on a reference replenishment rate and the toner replenishment rate.

12. The image forming apparatus according to claim 11,

the processor subtracts a correction value from the toner remaining amount when the toner replenishment rate is greater than the reference replenishment rate.

13. The image forming apparatus according to claim 12,

the processor determines the correction value based on a difference between the toner replenishment rate and the reference replenishment rate.

14. The image forming apparatus according to claim 11,

the processor adds a correction value to the toner remaining amount when the toner replenishment rate is smaller than the reference replenishment rate.

15. The image forming apparatus according to claim 14,

the processor determines the correction value based on a difference between the toner replenishment rate and the reference replenishment rate.

16. The image forming apparatus according to claim 11,

when the toner remaining amount is less than a predetermined threshold, the processor does not correct the toner remaining amount.

17. The image forming apparatus according to claim 10,

the processor detects near-end when the remaining toner amount is less than a preset near-end threshold.

Background

The image forming apparatus performs an image forming process of receiving toner from a toner cartridge and forming a toner image on a photosensitive drum. The image forming apparatus transfers a toner image of the photoconductive drum to a print medium.

The image forming apparatus calculates the remaining toner amount in the toner cartridge based on a driving amount (driving time) of a motor (toner replenishment motor) for rotating a screw for feeding toner from the toner cartridge to the image forming apparatus, a pixel amount (pixel count value) of image data for printing, and the like.

There are individual differences between the main body of the image forming apparatus and the toner cartridge. The toner supply amount per driving time varies due to individual differences. The deviation caused by the individual difference of the image forming apparatus can be corrected by a "correction amount" set in advance. However, in order to correct the variation due to the individual difference of the toner cartridges, there is a problem that it is necessary to have a "correction amount" for each toner cartridge.

Disclosure of Invention

An image forming apparatus according to an embodiment includes: a photosensitive drum; an exposure device that exposes the photosensitive drum based on image data; a developing device that forms a toner image on the photoconductive drum with toner supplied from a toner cartridge; a toner replenishment motor configured to supply toner from the toner cartridge to the developing device; and a processor that calculates a toner remaining amount in the toner cartridge based on a toner replenishment rate calculated based on a pixel count value of the image data and a driving time of the toner replenishment motor, a preset reference replenishment rate, and the driving time of the toner replenishment motor.

A method of controlling an image forming apparatus according to an embodiment, the image forming apparatus includes: a photosensitive drum; an exposure device that exposes the photosensitive drum based on image data; a developing device that forms a toner image on the photoconductive drum with toner supplied from a toner cartridge; a toner replenishment motor configured to supply toner from the toner cartridge to the developing device; and a processor that calculates a toner remaining amount in the toner cartridge based on a toner replenishment rate calculated based on a pixel count value of the image data and a driving time of the toner replenishment motor, a preset reference replenishment rate, and the driving time of the toner replenishment motor.

An image forming apparatus according to an embodiment includes: a photosensitive drum; an exposure device that exposes the photosensitive drum based on image data; a developing device that forms a toner image on the photoconductive drum with toner supplied from a toner cartridge; a toner replenishment motor configured to supply toner from the toner cartridge to the developing device; and a processor for calculating a toner remaining amount in the toner cartridge based on a toner replenishment rate calculated based on a pixel count value of the image data and a driving time of the toner replenishment motor, a preset reference replenishment rate, and a pixel count value.

Drawings

Fig. 1 is a diagram illustrating an example of the configuration of an image forming apparatus according to an embodiment.

Fig. 2 is a diagram for explaining a configuration example of a part of an image forming section according to an embodiment.

Fig. 3 is an explanatory diagram for explaining an example of the operation of the image forming apparatus according to the embodiment.

Fig. 4 is an explanatory diagram for explaining an example of the operation of the image forming apparatus according to the embodiment.

Fig. 5 is an explanatory diagram for explaining an example of the operation of the image forming apparatus according to the embodiment.

Fig. 6 is an explanatory diagram for explaining an example of the operation of the image forming apparatus according to the embodiment.

Description of the reference numerals

1 … image forming apparatus; 2 … toner cartridge; 11 … a housing; 12 … communication interface; 13 … system controller; 14 … display part; 15 … operating interface; 16 … paper tray; 17 … paper discharge tray; 18 … conveying part; 19 … an image forming section; 20 … fuser; 21 … processor; 22 … memory; 31 … paper feeding and conveying path; 32 … paper discharge transport path; 33 … a pick-up roller; 41 … filling part; 42 … processing element; 43 … exposure device; 44 … transfer mechanism; 51 … toner container; 52 … toner delivery mechanism; 61 … toner supply motor; 71 … a photosensitive drum; a 72 … cleaner; 73 … charged charger; 74 … developer; 81 … developer container; 82 … stirring mechanism; 83 … developing roller; 84 … scraper blade; 85 … ATC sensor; 91 … primary transfer tape; 92 … secondary transfer counter roller; 93 … primary transfer roller; 94 … secondary transfer roller; 95 … heated roller; 96 … pressure roll.

Detailed Description

An image forming apparatus according to an embodiment includes a photoconductive drum, an exposure unit, a developing unit, a toner supply motor, and a processor. An exposer exposes the photosensitive drum based on image data. The developing device forms a toner image on the photosensitive drum with toner supplied from a toner cartridge. The toner replenishment motor supplies toner from the toner cartridge to the developing device. And a processor for calculating a toner remaining amount in the toner cartridge based on a toner replenishment rate calculated based on a pixel count value of the image data and a driving time of the toner replenishment motor, a preset reference replenishment rate, and the driving time of the toner replenishment motor.

Hereinafter, an image forming apparatus and a method of controlling the image forming apparatus according to an embodiment will be described with reference to the drawings.

Fig. 1 is an explanatory diagram for explaining a configuration example of an image forming apparatus 1 according to an embodiment.

The image forming apparatus 1 is, for example, a multifunction printer (MFP) that performs various processes such as image formation while conveying a recording medium such as a print medium. The image forming apparatus 1 is, for example, a solid-state scanning printer (for example, an LED printer) that scans an LED array and performs various processes such as image formation while conveying a recording medium such as a print medium.

For example, the image forming apparatus 1 includes a configuration that receives toner from the toner cartridge 2 and forms an image on a print medium with the received toner. The toner may be a single color toner, or may be a color toner of a color such as cyan, magenta, yellow, and black.

As shown in fig. 1, the image forming apparatus 1 includes a housing 11, a communication interface 12, a system controller 13, a display unit 14, an operation interface 15, a plurality of paper trays 16, a paper discharge tray 17, a conveying unit 18, an image forming unit 19, and a fixing unit 20.

The housing 11 is a main body of the image forming apparatus 1. The housing 11 houses a communication interface 12, a system controller 13, a display unit 14, an operation interface 15, a plurality of paper trays 16, a paper discharge tray 17, a conveying unit 18, an image forming unit 19, and a fixing unit 20.

The communication interface 12 is an interface for communicating with other devices. The communication interface 12 is used for communication with a host device (external device), for example. The communication interface 12 is configured as a LAN connector or the like, for example. The communication interface 12 may wirelessly communicate with another device according to standards such as Bluetooth (registered trademark) and Wi-fi (registered trademark).

The system controller 13 controls the image forming apparatus 1. The system controller 13 includes, for example, a processor 21 and a memory 22.

The processor 21 is an arithmetic element that performs arithmetic processing. The processor 21 is, for example, a CPU. The processor 21 performs various processes based on data such as a program stored in the memory 22. The processor 21 functions as a control unit capable of executing various operations by executing the program stored in the memory 22.

The memory 22 is a storage medium that stores programs, data used in the programs, and the like. The memory 22 also functions as a working memory. That is, the memory 22 temporarily stores data being processed by the processor 21, programs executed by the processor 21, and the like.

The processor 21 executes a program stored in the memory 22, thereby performing various information processing. For example, the processor 21 generates a print job based on an image acquired from an external device via the communication interface 12, for example. The processor 21 saves the generated print job to the memory 22.

The print job includes image data showing an image formed on the print medium P. The image data may be data for forming an image on one printing medium P or data for forming an image on a plurality of printing media P. Also, the print job includes information showing whether to print in color or monochrome.

The processor 21 functions as a controller (engine controller) that controls operations of the conveying unit 18, the image forming unit 19, and the fixing device 20 by executing a program stored in the memory 22. That is, the processor 21 controls the conveyance of the print medium P by the conveyance unit 18, the formation of an image on the print medium P by the image forming unit 19, the fixation of an image on the print medium P by the fixing unit 20, and the like.

The image forming apparatus 1 may be provided with an engine controller independently of the system controller 13. In this case, the engine controller performs control of conveying the printing medium P by the conveying unit 18, control of forming an image on the printing medium P by the image forming unit 19, control of fixing an image on the printing medium P by the fixing unit 20, and the like. In addition, in this case, the system controller 13 supplies information necessary for control of the engine controller to the engine controller.

The display unit 14 includes a display for displaying a screen based on an image signal input from a display control unit such as the system controller 13 or a graphic controller not shown. For example, information such as a screen for various settings of the image forming apparatus 1 and a toner remaining amount is displayed on the display of the display unit 14.

The operation interface 15 is connected to an operation member not shown. The operation interface 15 supplies an operation signal corresponding to the operation of the operation member to the system controller 13. The operation member is, for example, a touch sensor, a numeric keypad, a power key, a paper feed key, various function keys, a keyboard, or the like. The touch sensor acquires information indicating a position designated in a certain area. The touch sensor is configured as a touch panel integrally with the display unit 14, and inputs a signal indicating a touched position on the screen displayed on the display unit 14 to the system controller 13.

The plurality of paper trays 16 are cassettes that respectively store the printing media P. The paper tray 16 is configured to be able to supply the printing medium P from outside the housing 11. For example, the paper tray 16 is configured to be able to be pulled out from the housing 11.

The paper discharge tray 17 is a tray that supports the printing medium P discharged from the image forming apparatus 1.

Next, a configuration of the image forming apparatus 1 for conveying the printing medium P will be described.

The conveying unit 18 is a mechanism for conveying the printing medium P in the image forming apparatus 1. As shown in fig. 1, the conveying unit 18 includes a plurality of conveying paths. For example, the conveying unit 18 includes a paper feed conveying path 31 and a paper discharge conveying path 32.

The paper feed conveyance path 31 and the paper discharge conveyance path 32 each include a plurality of motors, a plurality of rollers, and a plurality of guides, not shown. The plurality of motors rotate the shafts based on the control of the system controller 13, thereby rotating the rollers in linkage with the rotation of the shafts. The plurality of rollers move the printing medium P by rotating. The plurality of guides controls a conveying direction of the printing medium P.

The paper feed conveyance path 31 takes in the print medium P from the paper tray 16, and feeds the taken-in print medium P to the image forming unit 19. The paper feed conveyance path 31 includes pickup rollers 33 corresponding to the respective paper trays. Each pickup roller 33 takes in the print medium P on the paper tray 16 to the paper feed conveyance path 31.

The paper discharge conveyance path 32 is a conveyance path through which the print medium P on which the image is formed is discharged from the housing 11. The printing medium P discharged from the discharge transport path 32 is supported by the discharge tray 17.

Next, the image forming section 19 will be explained.

The image forming unit 19 is configured to form an image on the printing medium P. Specifically, the image forming unit 19 forms an image on the print medium P based on the print job generated by the processor 21.

The image forming section 19 includes a plurality of loading sections 41, a plurality of process units 42, a plurality of exposers 43, and a transfer mechanism 44. The image forming section 19 includes a loading section 41 and an exposure unit 43 for each process unit 42. Since the plurality of process units 42, the plurality of loading units 41, and the plurality of exposure units 43 have the same configuration, one process unit 42, one loading unit 41, and one exposure unit 43 will be described as an example.

Fig. 2 is an explanatory diagram for explaining an example of a part of the configuration of the image forming unit 19.

First, the toner cartridge 2 mounted in the loading portion 41 will be described.

As shown in fig. 2, the toner cartridge 2 includes a toner container 51 and a toner feeding mechanism 52. The toner cartridge 2 includes an IC chip not shown.

The toner container 51 is a container for containing toner.

The toner delivery mechanism 52 is a mechanism for delivering the toner in the toner storage container 51. The toner delivery mechanism 52 is, for example, a screw provided in the toner container 51 and configured to deliver toner by rotation.

The IC chip includes a memory in which various control data are stored in advance. The control data is, for example, "identification code" or "near end threshold value". The "identification code" shows the kind, model, and the like of the toner cartridge 2. The "near-end threshold" is a threshold for causing the image forming apparatus 1 to determine whether or not the remaining amount of toner in the toner cartridge 2 is small.

Next, the loading section 41 to which the toner cartridge 2 is attached will be described.

As shown in fig. 2, the loading portion 41 is a module that mounts toner cartridges 2 each filled with toner. Each of the loading units 41 includes a space for mounting the toner cartridge 2 and a toner replenishment motor 61. Each of the loading units 41 includes a communication interface, not shown, for connecting the IC chip of the toner cartridge 2 to the system controller 13.

The toner supply motor 61 drives the toner delivery mechanism 52 of the toner cartridge 2 based on the control of the processor 21. When the toner cartridge 2 is loaded in the loading unit 41, the toner supply motor 61 is connected to the toner feeding mechanism 52 of the toner cartridge 2. The toner supply motor 61 rotates the shaft by energization based on the control of the processor 21, and drives the toner feeding mechanism 52 of the toner cartridge 2. The toner supply motor 61 drives the toner delivery mechanism 52 to supply the toner in the toner container 51 to a developing device described later.

Next, the processing unit 42 will be explained.

The process unit 42 is configured to form a toner image. For example, the plurality of process units 42 are provided for each toner type. For example, the plurality of process units 42 correspond to color toners of cyan, magenta, yellow, and black, respectively. Specifically, toner cartridges 2 having toners of different colors are connected to the respective process units 42.

As shown in fig. 2, the process unit 42 includes a photosensitive drum 71, a cleaner 72, a charging charger 73, and a developing unit 74.

The photosensitive drum 71 is a photosensitive body including a cylindrical drum and a photosensitive layer formed on the outer peripheral surface of the drum. The photosensitive drum 71 is rotated at a constant speed by a driving mechanism not shown.

The cleaner 72 removes the toner remaining on the surface of the photoconductive drum 71.

The charging charger 73 uniformly charges the surface of the photosensitive drum 71. For example, the charging charger 73 applies a voltage to the photosensitive drum 71 using a charging roller, thereby charging the photosensitive drum 71 to a uniform negative potential. The charging roller rotates due to the rotation of the photosensitive drum 71 in a state where a predetermined pressure is applied to the photosensitive drum 71.

The developing unit 74 is a device for causing toner to adhere to the photoconductive drum 71. The developing device 74 includes a developer container 81, an agitation mechanism 82, a developing roller 83, a scraper 84, an Automatic Toner Controller (ATC) sensor 85, and the like.

The developer container 81 is a container for storing a developer including a toner and a carrier. The developer container 81 receives the toner sent from the toner cartridge 2 by the toner sending mechanism 52. The carrier is accommodated in the developer container 81 at the time of manufacturing the developer container 74.

The stirring mechanism 82 is driven by a motor, not shown, and stirs the toner and the carrier in the developer container 81.

The developing roller 83 rotates in the developer container 81, thereby causing the developer to adhere to the surface.

The doctor blade 84 is disposed at a predetermined interval from the surface of the developing roller 83. The doctor blade 84 removes a part of the developer adhering to the surface of the rotating developing roller 83. Thereby, a layer of the developer having a thickness corresponding to the gap between the doctor blade 84 and the surface of the developing roller 83 is formed on the surface of the developing roller 83.

The ATC sensor 85 is, for example, a magnetic flux sensor having a coil and detecting a voltage value generated in the coil. The detection voltage of the ATC sensor 85 changes according to the density of the magnetic flux from the toner in the developer container 81. That is, the system controller 13 can determine the concentration ratio of the toner remaining in the developer container 81 to the carrier based on the detection voltage of the ATC sensor 85.

Next, the exposure unit 43 will be explained.

The exposure unit 43 includes a plurality of light emitting elements. The exposure unit 43 irradiates the charged photosensitive drum 71 with light from the light emitting element, thereby forming a latent image on the photosensitive drum 71. The light emitting element is, for example, a Light Emitting Diode (LED) or a Laser Diode (LD). One light emitting element is configured to irradiate light to one point on the photosensitive drum 71. The plurality of light emitting elements are arranged in the main scanning direction which is a direction parallel to the rotation axis of the photosensitive drum 71.

The exposer 43 irradiates light onto the photosensitive drum 71 by a plurality of light emitting elements arranged in the main scanning direction, thereby forming a line amount of latent images on the photosensitive drum 71. The exposure unit 43 sequentially irradiates light to the rotating photosensitive drum 71, thereby forming a latent image of a plurality of lines.

In the above configuration, when light is irradiated from the exposure device 43 to the surface of the photosensitive drum 71 charged by the charging charger 73, an electrostatic latent image is formed. When the layer of the developer formed on the surface of the developing roller 83 is close to the surface of the photoconductive drum 71, the toner contained in the developer adheres to the latent image formed on the surface of the photoconductive drum 71. Thereby, a toner image is formed on the surface of the photoconductive drum 71.

Next, the transfer mechanism 44 will be explained.

The transfer mechanism 44 is configured to transfer the toner image formed on the surface of the photoconductive drum 71 to the print medium P.

As shown in fig. 1 and 2, the transfer mechanism 44 includes, for example, a primary transfer belt 91, a secondary transfer counter roller 92, a plurality of primary transfer rollers 93, and a secondary transfer roller 94.

The primary transfer belt 91 is an endless belt wound around the secondary transfer opposing roller 92 and a plurality of winding rollers. The inner surface (inner circumferential surface) of the primary transfer belt 91 is in contact with the secondary transfer counter roller 92 and the plurality of winding rollers, and the outer surface (outer circumferential surface) is opposed to the photosensitive drum 71 of the process unit 42.

The secondary transfer counter roller 92 is rotated by a motor not shown. The secondary transfer counter roller 92 rotates to convey the primary transfer belt 91 in a predetermined conveyance direction. The plurality of winding rollers are configured to be rotatable. The plurality of winding rollers rotate in accordance with the movement of the primary transfer belt 91 by the secondary transfer opposing roller 92.

The plurality of primary transfer rollers 93 are configured to bring the primary transfer belt 91 into contact with the photosensitive drums 71 of the process units 42. The plurality of primary transfer rollers 93 are provided so as to correspond to the photosensitive drums 71 of the plurality of process units 42. Specifically, each of the plurality of primary transfer rollers 93 is disposed at a position facing the corresponding photosensitive drum 71 of the process unit 42 via the primary transfer belt 91. The primary transfer roller 93 is in contact with the inner peripheral surface side of the primary transfer belt 91, and displaces the primary transfer belt 91 toward the photosensitive drum 71. Thereby, the primary transfer roller 93 brings the outer peripheral surface of the primary transfer belt 91 into contact with the photosensitive drum 71.

The secondary transfer roller 94 is disposed at a position facing the primary transfer belt 91. The secondary transfer roller 94 is in contact with the outer peripheral surface of the primary transfer belt 91 and applies pressure. Thereby, a transfer nip portion is formed in which the secondary transfer roller 94 is in close contact with the outer peripheral surface of the primary transfer belt 91. The secondary transfer roller 94 presses the printing medium P passing through the transfer nip portion to the outer peripheral surface of the primary transfer belt 91 when the printing medium P passes through the transfer nip portion.

The secondary transfer roller 94 and the secondary transfer counter roller 92 rotate to convey the printing medium P fed from the paper feed conveyance path 31 in a sandwiched state. Thereby, the printing medium P passes through the transfer nip.

In the above configuration, when the outer peripheral surface of the primary transfer belt 91 comes into contact with the photoconductive drum 71, the toner image formed on the surface of the photoconductive drum is transferred to the outer peripheral surface of the primary transfer belt 91. As shown in fig. 1, when the image forming portion 19 includes a plurality of process units 42, the primary transfer belt 91 receives toner images from the photoconductive drums 71 of the plurality of process units 42. The toner image transferred to the outer peripheral surface of the primary transfer belt 91 is conveyed to a transfer nip portion where the secondary transfer roller 94 is in close contact with the outer peripheral surface of the primary transfer belt 91, by the primary transfer belt 91. When the print medium P is present in the transfer nip portion, the toner image transferred to the outer peripheral surface of the primary transfer belt 91 is transferred to the print medium P in the transfer nip portion.

Next, a description will be given of a configuration related to fixing of the image forming apparatus 1.

The fixing device 20 melts the toner transferred to the print medium P and fixes the toner image. The fuser 20 operates under the control of the system controller 13. The fixing device 20 includes a heating member that applies heat to the printing medium P and a pressing member that applies pressure to the printing medium P. The heating member is, for example, a heating roller 95. In addition, the pressing member is a pressing roller 96, for example.

The heating roller 95 is a fixing rotating body that is rotated by a motor not shown. The heating roller 95 has a mandrel bar formed of metal in a hollow shape and an elastic layer formed on the outer periphery of the mandrel bar. The heating roller 95 is heated to a high temperature by a heater disposed inside the hollow mandrel bar. The heater is, for example, a halogen heater. The heater may be an Induction Heating (IH) heater that heats the plug by electromagnetic induction.

The pressure roller 96 is provided at a position facing the heat roller 95. The pressure roller 96 has a mandrel formed of metal with a predetermined outer diameter and an elastic layer formed on the outer periphery of the mandrel. The pressure roller 96 applies pressure to the heat roller 95 by stress applied from a tension member not shown. By applying pressure from the pressure roller 96 to the heat roller 95, a nip (fixing nip) is formed where the pressure roller 96 and the heat roller 95 are in close contact with each other. The pressure roller 96 is rotated by a motor not shown. The pressure roller 96 moves the printing medium P entering the fixing nip portion by rotating, and presses the printing medium P against the heat roller 95.

With the above configuration, the heat roller 95 and the pressure roller 96 apply heat and pressure to the print medium P passing through the fixing nip. Thereby, the toner image is fixed to the printing medium P passing through the fixing nip. The printing medium P having passed through the fixing nip is introduced into the paper discharge transport path 32 and discharged to the outside of the housing 11. Further, the fixing device 20 is not limited to the above-described configuration. The fixer 20 may also be constituted by the following on-demand manner: heat is applied to the print medium P on which the toner image is transferred through the film member, and the toner is melted and fixed.

Next, the control of the image forming apparatus 1 by the system controller 13 will be described.

First, toner supply from the toner cartridge 2 will be described.

The processor 21 of the system controller 13 calculates a concentration ratio of toner to carrier (toner concentration ratio) in the developer container 81 of the developer container 74 based on the detection result of the ATC sensor 85 of the process unit 42. The processor 21 drives the toner replenishment motor 61 when the toner concentration ratio is less than a predetermined threshold (toner replenishment threshold). Thus, the processor 21 drives the toner feeding mechanism 52 of the toner cartridge 2 to supply the toner in the toner container 51 to the developer container 81 of the developing container 74. For example, when detecting that the toner concentration is less than the toner replenishment threshold, the processor 21 drives the toner replenishment motor 61 for a predetermined time. When detecting that the toner concentration ratio is less than the toner replenishment threshold, the processor 21 may drive the toner replenishment motor 61 until the toner concentration ratio becomes equal to or higher than the toner replenishment threshold.

The processor 21 detects that the toner in the toner storage container 51 of the toner cartridge 2 is empty and toner is used up based on the toner concentration ratio when the toner replenishment motor 61 is driven. For example, the processor 21 detects toner empty when the toner concentration ratio cannot reach the toner replenishment threshold or more even if the toner replenishment motor 61 is driven.

Next, a process of calculating the toner remaining amount in the toner container 51 of the toner cartridge 2 will be described.

Fig. 3 is a flowchart for explaining the process of calculating the toner remaining amount.

The processor 21 integrates the pixel amount (pixel count value) based on the pixel value of the image data for printing (ACT 11). For example, the processor 21 integrates the pixel count value based on the pixel value of the image data for printing. Specifically, the processor 21 converts the image data into an image signal for driving each exposer 43. The processor 21 accumulates pixel count values for the respective color toners from the replacement of the toner cartridge 2 based on the image signal. The processor 21 saves the pixel count value to the memory 22, for example. The processor 21 updates the pixel count value on the memory 22 by accumulating the pixel count value.

The processor 21 integrates the driving amount (driving time) of the toner supply motor 61 from the replacement of the toner cartridge 2 (ACT 12). The processor 21 saves the drive time to the memory 22, for example. The processor 21 updates the driving time on the memory 22 by accumulating the driving time.

The processor 21 updates the toner remaining amount indicating the remaining amount of toner in the toner storage container 51 of the toner cartridge 2 (ACT 13). The processor 21 stores the toner remaining amount in the memory 22, for example. The processor 21 updates the toner remaining amount in the memory 22 based on, for example, any one of the integrated value of the pixel count value and the integrated value of the drive time.

The processor 21 calculates the toner supply amount based on, for example, any one of the integrated value of the pixel count value and the integrated value of the drive time. The toner supply amount is a ratio of the amount of toner supplied from the toner cartridge 2 to the developing device 74 to an initial value of the amount of toner in the toner storage container 51 of the toner cartridge 2. The initial value of the toner remaining amount on the memory 22 is 100 [% ]. The processor 21 updates the toner remaining amount [% ] on the memory 22 based on the calculated toner supply amount [% ] and the toner remaining amount [% ] on the memory 22.

First, an example of calculating the toner supply amount based on the drive time will be described.

The processor 21 calculates the rotation amount based on the rotation number (rotation amount) of the shaft of the toner replenishment motor 61 per driving time and the increment of the integrated value of the driving time from the previous update of the toner remaining amount. The processor 21 calculates a toner supply amount [% ] corresponding to the increase of the integrated value of the drive time based on the toner supply amount and the rotation amount for each rotation amount. The processor 21 updates the toner remaining amount [% ] in the memory 22 by subtracting the calculated toner supply amount [% ] from the toner remaining amount [% ] in the memory 22.

The number of rotations (rotation amount) of the shaft of the toner replenishment motor 61 per driving time and the toner supply amount per rotation amount are predetermined in consideration of an average value of evaluation results for each model of the image forming apparatus 1 and the toner cartridge 2, variations between the image forming apparatuses 1, and the like.

Next, an example of calculating the toner supply amount based on the pixel count value will be described. The processor 21 calculates the toner supply amount [% ] corresponding to the increment of the integrated value of the pixel count values based on the toner supply amount per pixel count value and the increment of the integrated value of the pixel count values from the previous updated toner remaining amount. The processor 21 updates the toner remaining amount [% ] in the memory 22 by subtracting the calculated toner supply amount [% ] from the toner remaining amount [% ] in the memory 22.

Further, the toner supply amount per pixel count value is determined in advance in consideration of an average value of evaluation results for each model of the image forming apparatus 1 and the toner cartridge 2, a deviation between the image forming apparatuses 1, and the like.

The processor 21 causes the display unit 14 to display the toner remaining amount in the memory 22 (ACT 14). The processor 21 may be configured to display the toner remaining amount on the display unit 14 in response to an operation input, or may be configured to notify other devices of the toner remaining amount via the communication interface 12.

FIG. 4 is an explanatory diagram for explaining an example of a relationship between a calculated value of a toner remaining amount (toner remaining amount calculated value) and an actual toner remaining amount (toner actual amount). The horizontal axis of fig. 4 represents the rotation amount (i.e., the integrated value of the drive time). The vertical axis of fig. 4 represents the toner remaining amount.

As shown in fig. 4, the calculated toner remaining amount may deviate from the actual toner amount due to variations in the toner cartridges 2. For example, the load of the toner delivery mechanism 52 of the toner cartridge 2 is different from the assumed load, and thus there is a possibility that the toner supply amount varies per driving time.

Therefore, the processor 21 performs a toner remaining amount correction process described later. In the toner remaining amount correction process, the processor 21 calculates the toner replenishment rate by dividing the value normalized by the integrated value of the pixel count values by the value normalized by the integrated value of the driving time of the toner replenishment motor 61. The processor 21 corrects the toner remaining amount based on the toner replenishment rate and a preset reference replenishment rate.

The toner remaining amount correction process will be described below.

The processor 21 determines whether or not the remaining toner amount in the memory 22 is equal to or more than a preset first threshold value (ACT 15). When determining that the remaining toner amount in the memory 22 is less than the first threshold value set in advance (no in ACT15), the processor 21 proceeds to the process of ACT25 described later. Thus, when determining that the remaining toner amount in the memory 22 is less than the preset first threshold, the processor 21 controls not to perform the toner remaining amount correction process.

When determining that the remaining toner amount in the memory 22 is equal to or greater than the first predetermined threshold value (yes in ACT15), the processor 21 determines whether or not the number of sheets of section printing is equal to or greater than a second predetermined threshold value (ACT 16). The number of interval printed sheets indicates the number of printed documents. The processor 21 resets the number of section prints each time the number of section prints reaches the second threshold or more. If the processor 21 determines that the number of sheets of section printing is less than the preset second threshold value (no in ACT16), the process proceeds to ACT 11. That is, the processor 21 repeatedly executes the processes of ACT11 to ACT16 until the number of section print sheets becomes equal to or greater than the second threshold value set in advance. For example, the processor 21 executes the processes of ACT11 to ACT16 every time one sheet or a predetermined number of sheets are printed.

When determining that the number of sheets of section printing is equal to or greater than the second threshold value set in advance (yes in ACT16), the processor 21 calculates a section replenishment rate that is a toner replenishment rate during printing of the number of sheets of section printing (ACT 17). That is, the processor 21 calculates the section replenishment rate each time the number of section prints reaches a preset second threshold.

The section replenishment rate is a ratio of the amount of toner used to the amount of toner replenished in a period from resetting of the number of section prints to reaching the second threshold value (hereinafter, simply referred to as a replenishment rate calculation section). The toner usage amount can be estimated from the pixel count value. The toner replenishment amount can be estimated from the driving time of the toner replenishment motor 61. The processor 21 calculates the interval replenishment rate based on the integrated value of the pixel count value and the integrated value of the driving time of the toner replenishment motor 61. For example, the processor 21 calculates the section replenishment rate based on the increase amount of the integrated value of the pixel count values in the replenishment rate calculation section and the increase amount of the integrated value of the driving time of the toner replenishment motor 61 in the replenishment rate calculation section. More specifically, the processor 21 calculates a value obtained by dividing the value normalized for the increase amount of the integrated value of the pixel count values by the value normalized for the increase amount of the integrated value of the driving time of the toner supply motor 61 as the section replenishment rate.

The processor 21 determines whether or not the number of times of calculation of the section replenishment rate is equal to or greater than a preset third threshold value (ACT 18). Every time the interval replenishment rate is calculated in the ACT17, the processor 21 counts the number of times of calculation of the interval replenishment rate (count up). The processor 21 resets the count value of the number of times of calculation of the interval replenishment rate each time the number of times of calculation of the interval replenishment rate reaches or exceeds a third threshold value set in advance. When determining that the number of times of calculation of the section replenishment rate is less than the preset third threshold value (no in ACT18), the processor 21 proceeds to the process of ACT 11. That is, the processor 21 repeatedly executes the processes of ACT11 to ACT18 until the number of times of calculation of the interval replenishment rate becomes equal to or greater than the third threshold value set in advance.

When determining that the number of times of calculation of the section replenishment rate is equal to or greater than the preset third threshold value (yes in ACT18), the processor 21 calculates a replenishment rate average value (ACT 19). The replenishment rate average value is an average value of a plurality of interval replenishment rates calculated by repeating the processes from ACT11 to ACT 18. The processor 21 may be configured to calculate a central tendency such as a central value of the plurality of interval replenishment rates.

The processor 21 determines whether or not the calculated average replenishment rate is equal to or higher than a preset reference replenishment rate (ACT 20). That is, the processor 21 calculates a difference between the calculated average replenishment rate and the reference replenishment rate and determines whether the difference is negative or positive. The reference replenishment rate is determined in advance in consideration of an average value of evaluation results for each model of the image forming apparatus 1 and the toner cartridge 2, a variation between the image forming apparatuses 1, and the like.

When determining that the calculated replenishment rate average value is equal to or greater than the preset reference replenishment rate (yes in ACT20), the processor 21 subtracts a preset correction amount [% ] from the toner remaining amount in the memory 22 updated in ACT13 (ACT21), and proceeds to the process of ACT 23. When the calculated average replenishment rate is equal to or higher than the preset reference replenishment rate, it is estimated that the toner supply amount per driving time or per pixel count value is larger than the reference. Therefore, the processor 21 can approximate the calculated value of the toner remaining amount to the actual toner remaining amount by subtracting the correction amount from the calculated toner remaining amount.

Further, when determining that the calculated replenishment rate average value is less than the preset reference replenishment rate (no in ACT20), the processor 21 adds a preset correction amount [% ] to the toner remaining amount in the memory 22 updated in ACT13 (ACT22), and proceeds to the process of ACT 23. When the calculated average replenishment rate is less than the preset reference replenishment rate, it is estimated that the toner supply amount per driving time or per pixel count value is less than the reference. Therefore, the processor 21 can approximate the calculated value of the toner remaining amount to the actual toner remaining amount by adding the correction amount to the calculated toner remaining amount.

FIG. 5 is an explanatory diagram for explaining an example of the relationship between the toner replenishment rate and the reference replenishment rate. The horizontal axis of fig. 5 represents the number of printed sheets. The vertical axis of fig. 5 represents the toner replenishment rate. As shown in fig. 5, there is a possibility that the toner replenishment rate varies. However, as described above, by calculating the average of the replenishment rates in the plurality of sections and comparing the average with the reference replenishment rate, it is possible to prevent the magnitude relationship between the average replenishment rate and the reference replenishment rate from being frequently switched.

Further, the processor 21 may determine the correction amounts in the ACT21 and ACT22 based on the absolute value of the difference between the replenishment rate average value and the reference replenishment rate.

Next, the processor 21 determines whether or not the corrected toner remaining amount is equal to or more than a preset near-end threshold (ACT 23). If the processor 21 determines that the corrected toner remaining amount is equal to or greater than the near-end threshold set in advance (yes in ACT23), the process proceeds to ACT 25. Further, when determining that the corrected toner remaining amount is less than the near end threshold set in advance (no in ACT23), the processor 21 detects a near end state (ACT24), and proceeds to the process of ACT 25. The near-end state indicates a state in which the toner in the toner cartridge 2 is low. When the near-end state is detected, the processor 21 outputs information (toner near-end display) prompting preparation for replacement of the toner cartridge via the display unit 14.

The processor 21 determines whether to end the processing (ACT 25). For example, when an operation to end the operation of image forming apparatus 1 is performed or when toner empty is detected, processor 21 determines that the process is to be ended. If the processor 21 determines that the processing is not to be ended (no in ACT25), the process proceeds to ACT 11. Thus, the processor 21 repeatedly executes the processes of ACT11 to ACT25, sequentially calculates and corrects the toner remaining amount. If the processor 21 determines that the processing is to be ended (yes in ACT25), the processing in fig. 3 is ended.

FIG. 6 is an explanatory diagram for explaining an example of the relationship between the corrected toner remaining amount and the actual toner amount. The horizontal axis of fig. 6 represents the rotation amount (i.e., the integrated value of the drive time). The vertical axis of fig. 6 indicates the toner remaining amount.

Fig. 6 shows an example in which the replenishment rate average value is smaller than the reference replenishment rate. According to this example, when the toner remaining amount calculated value is not corrected, the deviation between the actual toner amount and the toner remaining amount calculated value increases as the rotation amount increases. However, as described above, the processor 21 adds the correction amount to the toner remaining amount calculation value based on the result of comparison of the replenishment rate average value with the reference replenishment rate. As a result, the corrected toner remaining amount can be made close to the actual toner amount.

As described above, the image forming apparatus 1 includes the photoconductive drum 71, the exposer 43, the developing unit 74, the toner replenishment motor 61, and the processor 21. The processor 21 calculates the toner remaining amount based on the integrated value of the driving time of the toner replenishment motor 61 that supplies toner from the toner cartridge 2 to the developing device 74. The processor 21 calculates the toner replenishment rate based on the integrated value of the pixel count values of the image data for printing and the integrated value of the driving time of the toner replenishment motor 61. The processor 21 corrects the toner remaining amount based on a preset reference replenishment rate and a toner replenishment rate.

Thus, the processor 21 can make the corrected toner remaining amount close to the actual toner amount even when the "correction amount" is not set for each toner cartridge 2. That is, the image forming apparatus 1 can correct the deviation caused by the individual difference of the toner cartridges 2. As a result, the detection of the near-end state can be prevented from largely deviating from the actual toner remaining amount in the toner cartridge 2.

The functions described in the above embodiments are not limited to being implemented using hardware, and may be implemented by causing a computer to read a program in which the functions are described using software. Further, each function may be configured by appropriately selecting any one of software and hardware.

While several embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the invention. These embodiments can be implemented in other various forms, and various omissions, substitutions, and changes can be made without departing from the spirit of the invention. These embodiments and modifications are included in the scope and spirit of the invention, and are also included in the invention described in the claims and the equivalent scope thereof.