Image forming apparatus

Abstract

To further develop control for previously reducing the amount of toner in other developing cartridges which may be replaced at the same time when at least one of a plurality of developing cartridges which can be replenished is replaced.SOLUTION: When the first usage amount of the first developing cartridge is larger than the first threshold value and the second usage amount of the second developing cartridge is larger than a second threshold value that is smaller than the first threshold value and is smaller than a third threshold value that is larger than the second threshold value and is equal to or smaller than the first threshold value, the controller executes third small amount supply control in which a second supply amount to the second developing cartridge is larger than the second small amount supply control and is smaller than the second normal supply control.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus for forming an image on a recording medium. [Background technology]

[0002] Some image forming devices are equipped with a developer cartridge having a developing roller for supplying toner to a photosensitive drum, and a toner cartridge that shares toner with the developer cartridge. The developer cartridge deteriorates with repeated image formation operations and must be periodically replaced with a new one. The timing of a notification for developer cartridge replacement is determined by the amount of use of the developer cartridge. Therefore, since a developer cartridge may be prompted for replacement while toner remains inside, a known system for replenishable developer cartridges is one that controls the amount of toner replenished according to the amount of use (Patent Document 1). Patent Document 1 also discloses a control system that reduces the amount of toner in other developer cartridges that may be replaced at the same time. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2016-184027 Summary of the Invention [Problem to be solved by the invention]

[0004] To further develop control for reducing in advance the amount of toner in other developing cartridges that may be replaced at the same time when at least one of a plurality of replenishable developing cartridges is replaced. [Means for solving the problem]

[0005] A first aspect of the present invention provides a device comprising: a device main body; a first developing cartridge provided with a first toner storage section for storing a first toner, the first developing cartridge being detachable from the device main body; a second developing cartridge provided with a second toner storage section for storing a second toner, the second developing cartridge being detachable from the device main body; a first toner cartridge that stores the first toner for replenishing the first toner in the first toner storage section, the first toner cartridge being detachable from the device main body independently of the first developing cartridge; a second toner cartridge that stores the second toner for replenishing the second toner in the second toner storage section, the second toner cartridge being detachable from the device main body independently of the second developing cartridge; a first sensor that emits a first signal corresponding to an amount of the first toner stored in the first toner storage section; a second sensor that emits a second signal corresponding to the amount of the second toner stored in the second toner storage section; and a first usage amount of the first developing cartridge since the first developing cartridge was unused and a second usage amount of the second developing cartridge since the second developing cartridge was unused. a control unit that counts a first usage amount and a second usage amount, and controls so that a first replenishment operation of replenishing the first toner from the first toner cartridge to the first toner accommodating unit is executed in accordance with the magnitude of the first signal, and a second replenishment operation of replenishing the second toner from the second toner cartridge to the second toner accommodating unit is executed in accordance with the magnitude of the second signal, and controls a first replenishment amount that is the replenishment amount of the first toner to the first toner accommodating unit and a second replenishment amount that is the replenishment amount of the second toner to the second toner accommodating unit, wherein the control unit executes first normal replenishment control for the first developing cartridge when the first usage amount is less than a first threshold, and executes first small amount replenishment control for the first developing cartridge when the first usage amount is more than the first threshold, and executes second normal replenishment control for the second developing cartridge when the second usage amount is less than the first threshold, and executes second small amount replenishment control when the second usage amount is more than the first threshold, andWhen a threshold value less than the first threshold value is set as a second threshold value, and a threshold value greater than the second threshold value and equal to or less than the first threshold value is set as a third threshold value, When the first usage amount is greater than a first threshold value and the second usage amount is greater than the second threshold value and less than the third threshold value, a third small amount replenishment control is executed in which a second replenishment amount for the second developing cartridge is greater than that of the second small amount replenishment control and less than that of the second normal replenishment control, When the first usage amount is less than the first threshold value and the second usage amount is greater than the second threshold value and less than the third threshold value, the second normal replenishment control is executed. [Effects of the Invention]

[0006] It is possible to further develop the control for reducing the amount of toner in other developing cartridges that may be replaced at the same time that at least one of a plurality of replenishable developing cartridges is replaced. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic cross-sectional view of an image forming apparatus according to a first embodiment. [Figure 2] 4 is a flowchart showing toner supply control according to the first embodiment. [Figure 3] FIG. 4 is a diagram showing the relationship between the amount of toner used and the amount of toner in the process cartridge according to the first embodiment. [Figure 4] FIG. 4 is a diagram showing the relationship between the amount of toner used and the amount of toner in the process cartridge according to the first embodiment. [Figure 5] 10 is a flowchart showing toner supply control according to the second embodiment. [Figure 6] FIG. 10 is a diagram showing the relationship between the amount of toner and the amount of usage of the process cartridge according to the second embodiment. [Figure 7] FIG. 2 is a control block diagram according to the first and second embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0008] Example 1 [Configuration of image forming device] FIG. 1 is a cross-sectional view showing a schematic configuration of an image forming apparatus 1 according to this embodiment. The image forming apparatus 1 shown in FIG. 1 includes process cartridges 6Y, 6M, 6C, and 6K (corresponding to a first developer cartridge, a second developer cartridge, a third developer cartridge, and a fourth developer cartridge, respectively) that are image forming units that form images with toner colors of yellow (Y), magenta (M), cyan (C), and black (K). These are detachably mounted to an apparatus main body 100. Note that each process cartridge 6 has the same configuration and operation. Furthermore, the suffixes Y, M, C, and K added to the reference numerals of components constituting the process cartridge 6 indicate that the components use toner colors of yellow (Y), magenta (M), cyan (C), and black (K), respectively. Similarly, the suffixes Y, M, C, and K added to the reference numerals of components other than the process cartridge 6 indicate that the components correspond to the process cartridge 6 with toner colors of yellow (Y), magenta (M), cyan (C), and black (K), respectively. Hereinafter, the Y, M, C, and K suffixed to the symbols may be written as YK.

[0009] The process cartridge 6Y according to this embodiment includes a photosensitive drum 7Y, a charging device 8Y, a developing unit 9Y, a cleaning blade 10Y, and a memory 33Y (non-volatile memory). The photosensitive drum 7Y is rotatably supported by the frame of the process cartridge 6Y. The developing unit 9Y includes a storage section (first toner storage section) that stores toner and a developing roller 11Y (first developing roller) that carries toner, and the developing roller 11Y is configured to be able to contact and separate from the photosensitive drum 7Y. Similarly, the process cartridge 6M includes a photosensitive drum 7M, a charging device 8M, a developing unit 9M, a cleaning blade 10M, and a memory 33M. The photosensitive drum 7M is rotatably supported by the frame of the process cartridge 6M. The developing unit 9M has a container (second toner container) for containing toner, and a developing roller 11M (second developing roller) for carrying toner, and the developing roller 11M is configured to be able to come into contact with and separate from the photosensitive drum 7M. The same applies to the process cartridges 6C and 6K.

[0010] Below the process cartridges 6Y to 6K, toner cartridges 13Y, 13M, 13C, and 13K (corresponding to the first toner cartridge, second toner cartridge, third toner cartridge, and fourth toner cartridge) are arranged in this order in the direction in which the process cartridges 6Y to 6K are aligned. The toner cartridges 13Y to 13K are configured to be detachable from the device main body 100. The toner cartridge 13Y is configured to be detachable from the device main body 100 independently of the process cartridge 6Y. The toner cartridge 13M is configured to be detachable from the device main body 100 independently of the process cartridge 6M. The same applies to the toner cartridges 13C and 13K.

[0011] Toner conveying device 14Y conveys and replenishes toner supplied from toner cartridge 13Y to process cartridge 6Y. Toner conveying drive device 15Y, located below toner conveying device 14Y, drives toner conveying device 14Y. Toner conveying device 14M conveys and replenishes toner supplied from toner cartridge 13M to process cartridge 6M. Toner conveying drive device 15M, located below toner conveying device 14M, drives toner conveying device 14M. The same applies to toner conveying drive devices 15C and 15K.

[0012] An intermediate transfer unit 16 is provided above the developing units 9Y-K. The intermediate transfer unit 16 includes an intermediate transfer belt 18 and multiple tension rollers around which the intermediate transfer belt 18 is tensioned, and is detachably attached to the main body of the image forming apparatus 1. The intermediate transfer belt 18 is a rotatable, endless belt that is tensioned around multiple tension rollers. Primary transfer rollers 19Y, 19M, 19C, and 19K, which serve as primary transfer members, are positioned opposite the photosensitive drums 7Y-K across the intermediate transfer belt 18, forming a primary transfer portion. At each primary transfer portion, a high voltage is applied to the primary transfer rollers 19Y-K, and the color toner images formed on the photosensitive drums 7Y-K of the developing devices 6Y-K are transferred onto the intermediate transfer belt 18 so as to be superimposed on each other.

[0013] The control unit 60, which serves as a control means, includes a CPU, memory, an input / output interface, a bus, a counting unit 60a (counting means), an acquisition unit 60b, and other components. It communicates with the sensor unit 28, display unit 90, power supply unit 70, memory 33, and external devices (e.g., personal computers), among others, to perform various processes. The control unit 60 also receives image data from external devices and controls each device in the image forming apparatus 1 to perform image formation operations based on the received image data. The power supply unit 70 includes a high-voltage power supply that supplies power to each device in the image forming apparatus 1, such as the charging devices 8Y-K, the developing units 9Y-K, and the laser scanner unit 12. The drive unit 80 is a drive source for driving each device in the image forming apparatus 1, and includes motors that rotate the photosensitive drums 7Y-K, the developing rollers 11Y-K, the screws 77Y and 77M (first and second supply members) in the toner conveying device 14, and various other rollers. The display unit 90 functions as a display / notification unit that notifies users and service personnel of information related to the image forming apparatus 1. By configuring the display unit 90 as a touch panel, it also functions as an input device for inputting data and operation instructions.

[0014] When the control unit 60 receives a print job including image data from an external device, it executes the following image forming operation. Specifically, the control unit 60 charges the surface of the photosensitive drum 7Y to a uniform potential using the charging device 8Y, and then causes the laser scanner unit 12 to irradiate the photosensitive drum 7Y of the process cartridge 6Y with laser light corresponding to the image data, thereby forming an electrostatic latent image on the surface of the photosensitive drum 7Y. Next, the control unit 60 supplies toner from the developing roller 11Y to the electrostatic latent image formed on the photosensitive drum 7Y, causing the toner to adhere to the electrostatic latent image, thereby forming a yellow toner image on the photosensitive drum 7Y. The yellow toner image formed on the photosensitive drum 7Y is transferred to the intermediate transfer belt 18 by the primary transfer roller 19. Similarly, the toner images of each color formed on the photosensitive drums 7M, 7C, and 7K are sequentially transferred to the intermediate transfer belt 18, thereby forming a four-color toner image on the surface of the intermediate transfer belt 18. The four-color toner image formed on the intermediate transfer belt 18 is conveyed to a secondary transfer portion where the intermediate transfer belt 18 contacts a secondary transfer roller 21 as the intermediate transfer belt 18 rotates.

[0015] 1, the image forming apparatus 1 is provided with a paper cassette 2 in the lower part of the main body, which stores recording materials 4. In synchronization with the image forming operation in the process cartridge 6 described above, the recording materials 4 stored in the paper cassette 2 are separated and fed one by one by a cassette paper feeding unit 3 disposed downstream in the recording material conveyance direction of the paper cassette 2. The fed recording materials 4 are transported to a secondary transfer unit by registration rollers 5.

[0016] A secondary transfer roller 21 constituting a secondary transfer member contacts the intermediate transfer belt 18 and forms a secondary transfer portion with an opposing roller via the intermediate transfer belt 18. In the secondary transfer portion, the toner image transferred onto the intermediate transfer belt 18 is transferred onto the recording material 4 fed from the paper cassette 2. Toner that is not transferred onto the recording material 4 in the secondary transfer portion and remains on the intermediate transfer belt 18 is removed by a cleaning unit 22.

[0017] The recording material 4 onto which the toner image has been transferred is transported to a fixing device 25. The fixing device 25 has a heating unit that heats the toner image, and a pressure roller that contacts the heating unit and pressurizes the recording material 4. The recording material 4 transported to the fixing device 25 is heated and pressurized by the heating unit and pressure roller of the fixing device 25, and the toner melts, thereby fixing the toner image to the recording material 4. Thereafter, the recording material 4 with the fixed toner image is transported to a pair of discharge rollers 26 and discharged onto a discharge tray 27. An image is formed on the surface of the recording material 4 by this series of image forming operations.

[0018] [Process cartridge replacement timing] The timing for replacing the process cartridges 6Y to 6K according to this embodiment will now be described. As shown in FIG. 7, the control unit 60 includes a counting unit 60a that counts the amount of use (accumulated amount of use) of each of the process cartridges 6Y to 6K since it was new (unused). The counting unit 60a cumulatively counts the amount of use of the photosensitive drum 7, the amount of use of the developing roller 11, and a correlation value that correlates with the amount of toner replenished to each process cartridge 6 (each developing unit 9). The timing for replacing the process cartridges 6Y to 6K is when any of the above three parameters reaches a threshold value set for that cartridge, and a message urging the user to replace the process cartridges 6Y to 6K is displayed on the display unit 90.

[0019] The usage amount of the photosensitive drum 7 is determined by storing the cumulative rotation time (cumulative number of rotations, operating time) of the photosensitive drum 7 in memory 33 (FIGS. 1 and 7) of the process cartridge 6, and calculating the ratio of the cumulative rotation time (cumulative number of rotations) to the total rotation time (total number of rotations) equivalent to the lifespan. The usage amount of the developing roller 11 is determined by storing the cumulative rotation time (cumulative number of rotations) of the developing roller 11 in non-volatile memory 33, and calculating the ratio of the cumulative rotation time (cumulative rotation time) to the total rotation time (total number of rotations) equivalent to the lifespan. The toner supply amount life detection is determined by storing the cumulative amount of toner supplied to the developing unit 9 in non-volatile memory 33, and calculating the ratio of the cumulative toner supply amount to the total toner supply amount equivalent to the lifespan.

[0020] The amount of toner in the process cartridge 6 is measured by a sensor unit 28. The sensor unit 28 emits light into the rotation path of an agitator (not shown) that agitates the toner in the developing unit 9, measures the amount of light that passes through, and outputs a signal corresponding to the amount of toner. As described above, an amount of toner equivalent to the amount of consumed toner is replenished to the developing unit 9, so the amount of toner in the developing unit 9 is controlled to be kept constant. The process cartridge 6Y is provided with a sensor unit 28 (first sensor) that emits a signal (first signal) corresponding to the amount of toner in the toner storage section. The process cartridge 6M is provided with a sensor unit 28 (second sensor) that emits a signal (second signal) corresponding to the amount of toner in the toner storage section.

[0021] In addition to the optical detection method described above, the sensor unit 28 may also employ an image dot number detection method that detects the amount of remaining toner by counting the number of dots in an image formed on the surface of the photosensitive drum 7. Alternatively, an electrostatic antenna remaining toner detection method may be employed, in which a conductive sheet or plate is placed inside the developing unit 9 and the amount of toner is detected by measuring the electrostatic capacitance.

[0022] The usage amount of the process cartridge 6 is defined as 0% when it is new (unused) and 100% when it is used up to the end of its lifespan (hereinafter referred to as the usage limit). In this embodiment, the process cartridge 6 reaches the end of its lifespan when the usage amount of either the photosensitive drum 7 or the developing roller 11 reaches its limit threshold. When the usage amount of the process cartridge 6 reaches the usage limit, the display unit 90 displays (notifies) information urging the user to replace the process cartridge 6 or information regarding the lifespan of the process cartridge 6.

[0023] [Controlling the amount of toner in the process cartridge] The timing for replacing the process cartridge 6 will now be explained. When the usage of the process cartridge 6 reaches its usage limit, it may cause image defects such as vertical streaks and fogging, and therefore must be replaced with a new one. The amount of toner (total amount) in the process cartridge 6 (in the developing unit 9) is controlled to a constant amount by repeatedly replenishing an amount of toner equal to the amount of toner consumed each time a predetermined amount of toner is consumed. Therefore, when replacing the process cartridge 6 with a new one, the process cartridge 6 with a certain amount of toner remaining will be discarded. Therefore, it is necessary to reduce the amount of toner in the process cartridge 6 as much as possible when replacing it with a new one. Therefore, it is preferable to gradually reduce the amount of toner in the process cartridge 6 by replenishing an amount of toner equal to the amount of toner consumed each time a predetermined amount of toner is consumed until the usage of the process cartridge 6 reaches its usage limit.

[0024] A flowchart of toner replenishment control according to this embodiment is shown in Fig. 2, and Fig. 3(a) shows the relationship between the amount of toner used by process cartridge 6Y (first amount of toner used) and the amount of toner inside process cartridge 6Y. The vertical axis in Fig. 3(a) represents the magnitude of the signal from sensor 28, which corresponds to the amount of toner inside process cartridge 6Y, but for ease of understanding, the following explanation will use the amount of toner. Toner replenishment to process cartridge 6Y is referred to as the first replenishment operation, and toner replenishment to process cartridge 6M is referred to as the second replenishment operation.

[0025] Immediately after the process cartridge 6Y is replenished with a first amount ΔT1 of toner as a first replenishment amount (S100), the acquisition unit 60b of the control unit 60 acquires a signal from the sensor unit 28 corresponding to the amount of toner in the process cartridge 6Y and stores the signal in the memory 33Y of the process cartridge 6Y (S101). The control unit 60 monitors the amount of toner in the process cartridge 6Y (the magnitude of the signal from the sensor unit 28) (S102). The control unit 60 determines whether the difference (variation) from the amount of toner (signal magnitude) stored in the memory 33Y is greater than a predetermined difference ΔZ (first predetermined amount) (S103). If the difference is smaller than the predetermined difference ΔZ (No in S103), toner is not replenished and the process returns to S102. If the difference is greater than the predetermined difference ΔZ (Yes in S103), the control unit 60 determines whether the usage amount of the process cartridge 6Y is greater than a threshold X (first threshold) (S104). In this embodiment, the threshold value X is 95% usage, but it is sufficient if the usage is between 90% and 95%. If the usage of the process cartridge 6Y is not greater than the threshold value X (No in S104), a first replenishment operation is performed to replenish the process cartridge 6Y with a first amount ΔT1 of toner as the first replenishment amount. This control of the first replenishment operation is defined as normal replenishment control (first normal replenishment control). The first amount ΔT1 is equal to the predetermined difference amount ΔZ. Therefore, in normal replenishment control, the amount of toner in the process cartridge 6Y fluctuates between the toner amount T0 and the toner amount T1 until the usage of the process cartridge 6Y in FIG. 3(a) reaches the threshold value X, but remains constant.

[0026] If the usage amount of the process cartridge 6Y is greater than the threshold X (Yes in S104), a first replenishment operation is performed to replenish the process cartridge 6Y with a second amount ΔT2, which is less than the first amount ΔT1, as the first replenishment amount. This control of the first replenishment operation is defined as small amount replenishment control (first small amount replenishment control). Because the second amount ΔT2 is less than the predetermined difference amount ΔZ, the amount of toner in the process cartridge 6Y decreases as the usage amount of the process cartridge 6Y increases due to the small amount replenishment control. Therefore, it is possible to reduce the amount of toner in the process cartridge 6Y when the usage amount of the process cartridge 6Y reaches the usage limit. In this embodiment, the ratio of the second amount ΔT2 to the first amount ΔT1 is greater than or equal to 0 and less than 0.5 (0 means toner replenishment is stopped).

[0027] Normal replenishment control (second normal replenishment control) and small amount replenishment control (second small amount replenishment control) are also executed for process cartridge 6M. The change in the amount of toner in process cartridge 6M according to the amount of toner used is as shown in FIG. 3(b). The normal replenishment control and small amount replenishment control for process cartridge 6M are the same as those for process cartridge 6Y, so a detailed description will be omitted. Similar operations are also executed for process cartridges 6C and 6K.

[0028] Next, consider the case where the usage of process cartridge 6Y is greater than the usage of process cartridge 6M, and the usage of process cartridge 6Y reaches its limit, causing both cartridges 6Y and 6M to be replaced simultaneously. Figure 4(a) shows the relationship between the usage of process cartridge 6M and the amount of toner in process cartridge 6M in a comparative example. Figures 4(b) and 4(c) show the relationship between the usage of process cartridge 6M and the amount of toner in process cartridge 6M in this embodiment.

[0029] In the comparative example, regardless of the amount of usage of process cartridge 6Y, normal replenishment control is executed for process cartridge 6M when the amount of usage of process cartridge 6M is less than threshold value X, and small amount replenishment control is executed when the amount of usage is more than threshold value X. As a result, the amount of toner in process cartridge 6M at the time when process cartridge 6Y reaches the usage limit amount (Yellow-max) becomes toner amount Tr1.

[0030] In this embodiment, as shown in FIG. 2, it is determined whether the usage amount (second usage amount) of the process cartridge 6M is greater than threshold value Y (third threshold value) (S106). In this embodiment, as shown in FIG. 4(b), threshold value Y is 90% usage, which is less than threshold value X of 95% usage. Note that threshold value Y may be in the range of 80% to 90% usage. If the usage amount of the process cartridge 6M is not greater than threshold value Y (No in S106), in the next toner replenishment control for the process cartridge 6M, normal replenishment control (second normal replenishment control) is executed to replenish the amount of toner by the first amount ΔT1 as the second replenishment amount each time the amount of toner in the process cartridge 6M decreases by difference amount ΔZ (S108). If the usage amount of process cartridge 6M is greater than threshold Y (Yes in S106), in the next toner supply control for process cartridge 6M, a small amount of toner supply control (second small amount of toner supply control) is executed to supply a second amount of toner ΔT2 less than the first amount ΔT1 as a second supply amount each time the amount of toner in process cartridge 6M decreases by difference amount ΔZ (S107). As a result, as shown in FIG. 4(b), when process cartridge 6Y reaches its limit usage amount (usage amount 100%) (Yellow-max), the amount of toner in process cartridge 6M can be reduced to toner amount Tr2, which is less than toner amount Tr1.

[0031] As described above, according to this embodiment, when the process cartridge 6 with the greatest usage among the process cartridges 6Y to 6K reaches its usage limit, the amounts of toner in the other process cartridges that have not yet reached their usage limit and can be replaced at the same time can be reduced, thereby saving toner in the other process cartridges.

[0032] The second amount ΔT2, which is the amount of toner replenished during the small amount replenishment control of the process cartridge M in this embodiment, is the same amount as during the small amount replenishment control of the process cartridge Y, but it does not have to be the second amount ΔT2 as long as it is less than the first amount ΔT1.

[0033] Next, FIG. 4C shows the transition of the toner amount in the process cartridge 6M in a modified example of this embodiment. When the usage amount of the process cartridge 6M is less than the threshold Y1 (the same as the threshold Y in this embodiment), normal replenishment control (second normal replenishment control) is performed each time the toner amount in the process cartridge 6M decreases by the difference amount ΔZ. When the usage amount of the process cartridge 6M is greater than the predetermined value Y1, third small amount replenishment control is performed from the next toner replenishment. This third amount replenishment control replenishes toner by a third amount ΔT3, which is less than the first amount ΔT1 and greater than the second amount ΔT2. This second small amount replenishment control continues until the usage amount of the process cartridge 6M reaches a predetermined amount Y2, which is greater than the threshold Y1 but less than the threshold X. When the usage amount of the process cartridge 6M exceeds the predetermined amount Y2, second small amount replenishment control is performed to replenish the second amount ΔT2. According to this modified example, the amount of toner in the process cartridge 6M can be set to the toner amount Tr3 when the usage amount of the process cartridge 6Y reaches the limit usage amount. The toner amount Tr3 is less than the toner amount Tr1 in the comparative example and more than the toner amount Tr2 in this embodiment. Therefore, by not reducing the amount of toner in the process cartridge 6M too much, it is possible to suppress deterioration of the toner in the process cartridge 6M when the process cartridge 6M is not replaced at the same time as the 6Y. In this modified example, the threshold value Y2 may be equal to the threshold value X. In other words, the threshold value Y2 is greater than the threshold value Y1 and less than or equal to the threshold value X.

[0034] In this embodiment, in order to simply explain toner supply control, the case has been described in which the process cartridge 6Y is assumed to have the greatest amount of usage, and toner supply control for the process cartridge 6M is executed in accordance with the amount of usage of the process cartridge 6Y. However, it is not necessary for there to be just one process cartridge for which toner supply control is executed in accordance with the amount of usage of the process cartridge that has the greatest amount of usage among the process cartridges 6Y to 6K.

[0035] Furthermore, in this embodiment, a process cartridge having a photosensitive drum, a developing roller, and a toner storage section is used, but a developing cartridge having a developing roller and a toner storage section without a photosensitive drum may also be used.

[0036] Example 2 The control of this embodiment will now be described. In the first embodiment, small-amount replenishment control for the process cartridge 6M, which is executed in accordance with the amount of use of the process cartridge 6Y, was described. In this embodiment, a case where the process cartridge 6M is not replaced with a new one at the same time as the process cartridge 6Y, will be described. In this case, the amount of toner in the process cartridge 6Y is less than when normal replenishment control is performed. If the process cartridge 6M is continued to be used in this state, a load is placed on the small amount of toner, which may accelerate toner deterioration. Accelerated toner deterioration may cause problems such as the occurrence of development streaks due to toner fusion on the developing blade and deterioration in temperature due to reduced toner fluidity. Therefore, in this embodiment, when the process cartridge 6M is not replaced with a new one at the same time as the process cartridge 6Y, increased replenishment control is performed to increase the amount of toner in the process cartridge 6M.

[0037] The increased replenishment control according to this embodiment will be described below with reference to FIG. 5. When the control unit 60 detects through communication with the memory 33Y that the process cartridge 6Y has been replaced with a new one (S201), the control unit 60 detects through communication with the memory 33M whether the process cartridge 6M has also been replaced with a new one (S202). If the answer to S202 is Yes, the control unit 60 executes normal replenishment control for the process cartridge 6M. If the answer to S202 is No, the control unit 60 determines whether the amount of usage of the process cartridge 6M is greater than threshold Y and less than threshold X (S203). If the answer to S203 is Yes, the control unit 60 determines whether the amount of usage of the process cartridge 6M is greater than threshold X (S204). If the answer to S204 is No, the amount of toner in the process cartridge 6M is less than threshold Y, so the control unit 60 executes normal replenishment control (S208). The normal replenishment control here refers to control in which the amount of toner in the process cartridge 6M fluctuates between toner amount T0 and toner amount T1 in FIGS. 6(a) and 6(b), and maintains the amount of toner in the process cartridge 6M at a constant level.

[0038] If S203 is Yes, first incremental replenishment control is executed (S205). This is the case when, in FIG. 6A, the usage amount of the process cartridge 6M is between thresholds Y and X, the process cartridge 6Y reaches its usage limit and the replacement timing (Yellow-Max) arrives, and it is detected that the process cartridge 6M has not been replaced. In the first incremental replenishment control, toner replenishment continues until the acquisition unit 60b acquires a signal from the sensor unit 28 corresponding to the toner amount T1 in the process cartridge 6M at the replacement timing (Yellow-Max). Then, it is determined whether the usage amount of the process cartridge 6M is greater than X (S207). If S207 is No, normal replenishment control is executed until S207 is Yes (S208). In other words, as shown in FIG. 6A, normal replenishment control is executed until the usage amount of the process cartridge 6M exceeds threshold X, and the toner amount in the process cartridge 6M is controlled to fluctuate between T0 and T1. If the answer is Yes in S207, small amount replenishment control is executed (S209), and the amount of toner in the process cartridge 6M gradually decreases, as shown in FIG. 6(a).

[0039] If the answer is Yes in S204, second increased supply control is executed (S206). This is the case when, in FIG. 6(b), the replacement timing (Yellow-Max) for process cartridge 6Y arrives when the amount of toner used in process cartridge 6M is greater than X, and it is detected that process cartridge 6M has not been replaced. In second increased supply control, toner supply continues until, at the replacement timing (Yellow-Max), acquisition unit 60b acquires a signal from sensor unit 28 corresponding to the toner amount T0 in process cartridge 6M. Then, after second increased supply control, small amount supply control is executed (S209), and the amount of toner in process cartridge 6M gradually decreases as the amount of toner used increases, as shown in FIG. 6(b).

[0040] By using this embodiment, it is possible to increase the amount of toner in at least one process cartridge that was not replaced at the same time as the process cartridge with the highest usage, which makes it less likely that defects such as development streaks will occur until the usage amount of the process cartridge reaches its limit usage amount.

[0041] In this embodiment, the amount of toner in the process cartridge 6M is restored to the same amount as during normal control by a single toner replenishment, but this is not limited to this. To minimize downtime related to toner replenishment, the toner replenishment may be performed in conjunction with normal image formation operations. Alternatively, the toner replenishment may be performed multiple times during the post-rotation sequence executed after image formation. If the toner amount can be quickly restored to the same amount as during normal control, it is desirable to minimize downtime and excess rotation.

[0042] In this embodiment, for the sake of simplicity, the control for two process cartridges, process cartridge Y and process cartridge M, will be described, but the present invention is not limited to this. Similar control can be performed even when there are two or three process cartridges that have not been replaced. [Explanation of symbols]

[0043] 6 Process cartridge 11 Developing roller 15 Toner cartridges 28 Sensor section X First Threshold Y Second Threshold Y2 Third Threshold

Claims

1. A device body, a first developing cartridge provided with a first toner containing portion for containing a first toner, the first developing cartridge being detachable from the device main body; a second developing cartridge provided with a second toner containing portion for containing a second toner, the second developing cartridge being detachable from the main body of the apparatus; a first toner cartridge that accommodates the first toner for replenishing the first toner in the first toner accommodating section, the first toner cartridge being detachable from the device main body independently of the first developing cartridge; a second toner cartridge that accommodates the second toner for replenishing the second toner in the second toner accommodating portion, the second toner cartridge being detachable from the device main body independently of the second developing cartridge; a first sensor that outputs a first signal corresponding to the amount of the first toner contained in the first toner container; a second sensor that outputs a second signal corresponding to the amount of the second toner contained in the second toner container; a control unit that counts a first usage amount of the first developing cartridge since it was unused and a second usage amount of the second developing cartridge since it was unused, and controls so that a first supply operation of supplying the first toner from the first toner cartridge to the first toner storage unit is executed in accordance with the magnitude of the first signal, and a second supply operation of supplying the second toner from the second toner cartridge to the second toner storage unit is executed in accordance with the magnitude of the second signal, and controls a first supply amount that is the supply amount of the first toner to the first toner storage unit and a second supply amount that is the supply amount of the second toner to the second toner storage unit; Equipped with The control unit When the first usage amount is less than a first threshold value, a first normal replenishment control is executed for the first developing cartridge; When the first usage amount is greater than a first threshold value, a first small amount replenishment control is executed for the first developing cartridge in which the first replenishment amount is smaller than that of the first normal replenishment control; When the second usage amount is less than the first threshold value, a second normal replenishment control is executed for the second developing cartridge; When the second usage amount is greater than a first threshold value, a second small amount replenishment control is executed in which the second replenishment amount is smaller than that of the second normal replenishment control; The control unit When a threshold value less than the first threshold value is set as a second threshold value, and a threshold value greater than the second threshold value and equal to or less than the first threshold value is set as a third threshold value, When the first usage amount is greater than a first threshold value and the second usage amount is greater than the second threshold value and less than the third threshold value, a third small amount replenishment control is executed in which a second replenishment amount for the second developing cartridge is greater than that of the second small amount replenishment control and less than that of the second normal replenishment control, When the first usage amount is smaller than the first threshold value and the second usage amount is larger than the second threshold value and smaller than the third threshold value, the second normal replenishment control is executed. The image forming apparatus is characterized by the above.

2. A notification unit is provided, When the first usage amount reaches a limit usage amount that is greater than the first threshold value, the notification unit notifies information that prompts replacement of the first developing cartridge, The first threshold is an amount equal to or greater than 90% and equal to or less than 95% of the limit usage amount.

2. The image forming apparatus according to claim 1, wherein:

3. The second threshold is an amount equal to or greater than 80% and equal to or less than 90% of the limit usage amount.

3. The image forming apparatus according to claim 2, wherein:

4. the first supply amount in the first supply operation is a supply amount of the first toner that is supplied every time the magnitude of the first signal changes by a first predetermined amount immediately after the first supply operation is performed, the second supply amount in the second supply operation is the amount of the second toner to be supplied each time the magnitude of the second signal changes by a second predetermined amount immediately after the second supply operation is performed; 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

5. a ratio of the second replenishment amount in the second small amount replenishment control to the second replenishment amount in the second normal replenishment control is equal to or greater than 0 and equal to or less than 0.5; 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

6. the first small amount of supply control has a shorter operation time for the first supply operation than the first normal supply control, so that the first small amount of supply control has a smaller first supply amount than the first normal supply control; the second small amount replenishment control has a shorter operation time for the second replenishment operation than the second normal replenishment control, and therefore the second replenishment amount is smaller in the second small amount replenishment control than in the second normal replenishment control; The third small amount replenishment control has a longer operation time of the second replenishment operation than the second small amount replenishment control, so that the third small amount replenishment control has a larger second replenishment amount than the second small amount replenishment control.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

7. a first supply member rotatable to supply the first toner to the first developing cartridge, and a second supply member rotatable to supply the second toner to the second developing cartridge; the number of rotations per unit time of the first supply member in the first small amount supply control is the same as the number of rotations per unit time of the first supply member in the first normal supply control, a rotation time of the first supply member during the first small amount supply control is shorter than a rotation time of the first supply member during the first normal supply control; the number of rotations per unit time of the second supply member in the second small amount supply control is the same as the number of rotations per unit time of the second supply member in the second normal supply control, a rotation time of the second supply member during the second small amount supply control is shorter than a rotation time of the second supply member during the second normal supply control; 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

8. the first developing cartridge has a first developing roller that carries the first toner, the second developing cartridge has a second developing roller that carries the second toner, the first usage amount is the cumulative number of rotations or cumulative rotation time of the first developing roller, the second usage amount is the cumulative number of rotations or cumulative rotation time of the second developing roller; 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

9. A device body, a first developing cartridge provided with a first toner containing portion for containing a first toner, the first developing cartridge being detachable from the device main body; a second developing cartridge provided with a second toner containing portion for containing a second toner, the second developing cartridge being detachable from the main body of the apparatus; a first toner cartridge that accommodates the first toner for replenishing the first toner in the first toner accommodating section, the first toner cartridge being detachable from the device main body independently of the first developing cartridge; a second toner cartridge that accommodates the second toner for replenishing the second toner in the second toner accommodating portion, the second toner cartridge being detachable from the device main body independently of the second developing cartridge; a first sensor that outputs a first signal corresponding to the amount of the first toner contained in the first toner container; a second sensor that outputs a second signal corresponding to the amount of the second toner contained in the second toner container; a control unit that counts a first usage amount of the first developing cartridge since it was unused and a second usage amount of the second developing cartridge since it was unused, and controls so that a first supply operation of supplying the first toner from the first toner cartridge to the first toner accommodating unit is executed in accordance with the magnitude of the first signal, and a second supply operation of supplying the second toner from the second toner cartridge to the second toner accommodating unit is executed in accordance with the magnitude of the second signal, and controls a first supply amount that is the supply amount of the first toner to the first toner accommodating unit and a second supply amount that is the supply amount of the second toner to the second toner accommodating unit; The notification department, Equipped with The control unit When the first usage amount is less than a first threshold value and the second usage amount is greater than a second threshold value that is less than the first threshold value and is less than the first threshold value, a first normal replenishment control is executed for the first developing cartridge and a second normal replenishment control is executed for the second developing cartridge; When the first usage amount is greater than a first threshold value and the second usage amount is greater than the second threshold value and less than the first threshold value, a first small amount replenishment control is executed for the first developing cartridge in which the first replenishment amount is less than that of the first normal replenishment control, and a second small amount replenishment control is executed for the second developing cartridge in which the second replenishment amount is less than that of the second normal replenishment control, the notification unit, when the first usage amount reaches a limit usage amount that is greater than the first threshold, notifies information urging replacement of the first developer cartridge or information related to a lifespan of the first developer cartridge, and, when the second usage amount reaches the limit usage amount, notifies information urging replacement of the second developer cartridge or information related to a lifespan of the second developer cartridge; The first threshold is an amount equal to or greater than 90% and equal to or less than 95% of the limit usage amount. The image forming apparatus is characterized by the above.

10. the first supply amount in the first supply operation is a supply amount of the first toner that is supplied every time the magnitude of the first signal changes by a first predetermined amount immediately after the first supply operation is performed, the second supply amount in the second supply operation is the amount of the second toner to be supplied each time the magnitude of the second signal changes by a second predetermined amount immediately after the second supply operation is performed; 10. The image forming apparatus according to claim 9,

11. a ratio of the second replenishment amount in the second small amount replenishment control to the second replenishment amount in the second normal replenishment control is equal to or greater than 0 and equal to or less than 0.5; 10. The image forming apparatus according to claim 9,

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