JP2024051013A - Image forming device - Google Patents

Abstract

[Problem] Even if a user continues to use a developing unit after a replacement urging, it is desired to prevent problems with the cleaning device before they occur. [Solution] The image forming device of the present invention is an image forming device in which a latent image unit and a developing unit can be detachably attached to the device main body, the latent image unit has a cleaning member that removes developer from the surface of the image carrier, and the developing unit has a developer carrier. The image forming device further includes a control unit and a notification device that issues a notification regarding the promotion of replacement of the developing unit, and the control unit is characterized in that after the notification device issues the notification regarding the promotion of replacement, it acquires first information corresponding to the amount of use of the developing unit, and causes the notification device to issue a warning regarding protection of the latent image unit based on the acquired first information. [Selected Figure] Figure 5

Description

The present invention relates to an image forming apparatus that forms images using an electrophotographic method.

Conventionally, in image forming devices that form images on recording media such as recording paper, electrostatic latent images are formed in a latent image unit that includes a photosensitive drum as an image carrier, a charging device, and a cleaning device. The electrostatic latent image is then visualized in a development unit that includes toner as a developer and a developer carrier, thereby forming an image. In general, the lifespan of the latent image unit and the development unit are different. In other words, the lifespan of the latent image unit is determined by the degree of wear of the image carrier and the cleaning device, while the lifespan of the development unit is determined by the remaining amount of toner and the degree of deterioration of the toner due to repeated use. The lifespan of each unit varies depending on the user's usage conditions. For this reason, an image forming device has been proposed in which the latent image unit and the development unit are each separately integrated into a process cartridge (see Patent Document 1). This allows the latent image unit and the development unit to be used efficiently until the end of their lifespans.

JP 2004-279689 A

However, even when the operating history of a development unit reaches the threshold for encouraging replacement and the user is notified, the user may continue to use the development unit. This is because the reason for encouraging replacement of the development unit is deterioration of the toner inside the development unit due to repeated friction. Even if replacement of the development unit is encouraged due to toner deterioration, if there is still toner remaining, the user may continue to use the development unit even after the replacement is encouraged.

However, if the development unit continues to be used after the replacement prompt has been issued, there is a risk that the cleaning device may be damaged. If the cleaning device is damaged, problems such as vertical streaks in the image may occur.

Therefore, there is a need to further reduce problems with the cleaning device, even if the user continues to use the development unit after being prompted to replace it.

In order to achieve the above object, the image forming apparatus of the present invention is an image forming apparatus in which a latent image unit and a developing unit can be attached and detached to the main body of the apparatus, the latent image unit has a rotatable image carrier on which an electrostatic latent image is formed, and a cleaning member that contacts the image carrier to remove developer from the surface of the image carrier, the developing unit has a developer carrier that develops the electrostatic latent image formed on the image carrier with a developer image, and the image forming apparatus further includes a control unit and a notification device that issues a notification regarding the promotion of replacement of the developing unit, and the control unit acquires first information corresponding to the amount of use of the developing unit after the notification regarding the promotion of replacement by the notification device, and causes the notification device to issue a warning regarding protection of the latent image unit based on the acquired first information.

Alternatively, the image forming apparatus of the present invention is an image forming apparatus in which a latent image unit and a developing unit can be attached and detached to the main body of the apparatus, the latent image unit has a rotatable image carrier on which an electrostatic latent image is formed, and a cleaning member that contacts the image carrier to remove developer from the surface of the image carrier, the developing unit has a developer carrier that develops the electrostatic latent image formed on the image carrier with a developer image, and the image forming apparatus further has a charging means, a control unit, and an alarm device that issues an alarm regarding the promotion of replacement of the developing unit, and the control unit issues a warning according to the amount of usage of the developing unit. The control unit obtains first information, and causes the notification device to issue a notification regarding the promotion of replacement of the developing unit based on the obtained first information. After the notification regarding the promotion of replacement is issued, the control unit estimates the amount of film thickness reduction on the surface of the image carrier for a predetermined amount of usage of the latent image unit for the same combination of the developing unit and the latent image unit to be greater than the amount of film thickness reduction on the surface of the image carrier for the predetermined amount of usage before the notification regarding the promotion of replacement is issued. The control unit controls the charging bias to the charging means according to the film thickness on the surface of the image carrier.

This invention makes it possible to further reduce problems with the cleaning device, even if the user continues to use the development unit after being prompted to replace it.

FIG. 1 is an explanatory diagram of an image forming apparatus. Cross-sectional view of the drum cartridge taken along the longitudinal direction (direction of the rotation axis) A cross-sectional view taken along the longitudinal direction (rotation axis direction) of the developing cartridge. Control block diagram of an image forming apparatus Flowchart for notifying drum cartridge protection warning Enlarged view of the cleaning blade edge Flowchart for correcting the amount of film thickness reduction on the photosensitive drum Graph of toner fogging vs. Vback Graph of drum surface layer thickness potential and fogging characteristics

The following describes in detail the embodiments of the present invention with reference to the drawings. However, the dimensions, materials, shapes, and relative positions of the components described in the embodiments should be changed as appropriate depending on the configuration and various conditions of the device to which the invention is applied. In other words, it is not intended to limit the scope of the present invention to the embodiments below.

In this embodiment, if the development unit continues to be used after the replacement prompt threshold has been exceeded, a latent image unit protection warning is issued to the user. This makes it possible to prevent image defects such as vertical streaks caused by damage to the cleaning device. Furthermore, the later the latent image unit is used, the earlier the timing of issuing the latent image unit protection warning is, making it possible to issue the latent image unit protection warning in a more reliable manner to reduce damage.

First, the background will be explained. Figure 6 is an enlarged view of the cleaning blade edge portion, and is a diagram for explaining the mechanism by which edge chipping of the cleaning blade 6 occurs. The cleaning blade 6 is a blade member that extends in the counter direction to the rotation direction R of the photosensitive drum 1. The cleaning blade 6 comes into contact with the photosensitive drum 1 and cleans the surface of the photosensitive drum by scraping off the transfer residual toner on the photosensitive drum 1.

As shown in FIG. 6, the cleaning blade 6 abuts against the photosensitive drum 1 in the counter direction to the rotation direction R. That is, the edge E, which is the tip extending in the opposite direction to the moving direction of the photosensitive drum 1 relative to the cleaning blade 6, abuts against the surface of the photosensitive drum 1. Therefore, the edge E of the cleaning blade 6 is in a state of being rolled up in the moving direction of the photosensitive drum 1 as the photosensitive drum 1 rotates. The toner external additive that has been transferred to the photosensitive drum 1 described above accumulates in this rolled-up wedge portion (contact portion), forming a layer (hereinafter referred to as a blocking layer 14). That is, the toner external additive is supplied to the contact portion of the cleaning blade 6 with the photosensitive drum 1, and the blocking layer 14 is formed at the contact portion of the cleaning blade 6 with the photosensitive drum 1. A part of the toner external additive contained in this blocking layer 14 is interposed between the photosensitive drum 1 and the cleaning blade 6, thereby preventing an increase in frictional resistance between the photosensitive drum 1 and the cleaning blade 6.

However, if a developing cartridge 200 that has reached the end of its life continues to be used, the frictional resistance between the photosensitive drum 1 and the cleaning blade 6 increases, and part of the cleaning blade edge may chip off and become damaged (edge chipping). In terms of toner degradation, the toner in a developing unit that has reached the end of its life is almost gone, with the toner additives transferring to the photosensitive drum or becoming embedded in the toner due to repeated rubbing. This causes the blocking layer to become depleted, and the frictional resistance between the photosensitive drum and the cleaning blade to increase.

The reason why the usage of the drum cartridge 210 is related to edge chipping of the cleaning blade 6 will be explained. As the usage of the drum cartridge 210 increases, the edge of the cleaning blade 6 accumulates load due to stress caused by the rotation of the photosensitive drum 1 and the stopping and starting operation of the photosensitive drum 1. When the load on the edge of the cleaning blade 6 accumulates, the rubber on the edge eventually breaks, causing edge chipping. Therefore, the more the drum cartridge 210 is used, the more likely edge chipping of the cleaning blade 6 occurs. In other words, if the development unit is continued to be used after a replacement call during the latter half of the life of the latent image unit, damage to the cleaning device is more likely to occur.

[Image forming apparatus]
First, the overall configuration of the image forming apparatus will be described with reference to FIG. 1. The image forming apparatus includes a copying machine, a printer, a facsimile machine, a word processor, and a combination machine (multifunction printer) thereof using an electrophotographic image forming method or an electrostatic recording method. The image forming apparatus 100 is, for example, an A4 full-color laser beam printer using an in-line method or an intermediate transfer method, and can form a full-color image on a recording material (for example, recording paper, a plastic sheet, cloth, etc.) according to image information. The image information is input to the apparatus body of the image forming apparatus 100 from an image reading device connected to the apparatus body of the image forming apparatus 100, or a host device such as a personal computer connected to the apparatus body of the image forming apparatus 100 so as to be communicable therewith. The image forming apparatus 100 has imaging units SY, SM, SC, and SK for forming images of each color of yellow (Y), magenta (M), cyan (C), and black (K). In the first embodiment, the imaging units SY, SM, SC, and SK are arranged in a row in a direction intersecting the vertical direction. The imaging units SY, SM, SC, and SK are each composed of a drum cartridge 210 (210Y, 210M, 210C, and 210K) as a latent image unit and a developing cartridge 200 (200Y, 200M, 200C, and 200K) as a developing unit. Each of the developing cartridge 200 and the drum cartridge 210 is detachable from the main body of the image forming apparatus 100 via a mounting means such as a mounting guide and a positioning member provided in the main body of the image forming apparatus 100. In the first embodiment, the drum cartridges 210 for each color all have the same shape, and the developing cartridges 200 for each color all have the same shape. The developing cartridges 200 for each color contain toner of each color, namely, yellow (Y), magenta (M), cyan (C), and black (K).

The photosensitive drum 1 is a rotatable image carrier, and is rotated by a driving means (driving source). A scanner unit (exposure device) 30 is arranged around the photosensitive drum 1. The scanner unit 30 is an exposure means that irradiates a laser based on image information to form an electrostatic image (electrostatic latent image) on the photosensitive drum 1. The laser exposure is started for each scanning line in the main scanning direction (direction perpendicular to the conveying direction of the recording material 12) from a position signal in a polygon scanner called BD (Beam Detect). On the other hand, in the sub-scanning direction (conveying direction of the recording material 12), it is delayed by a predetermined time from a TOP (top of paper) signal that starts from a switch (not shown) in the conveying path of the recording material 12. This allows the four imaging units SY, SM, SC, and SK to always perform laser exposure to the same position on the photosensitive drum 1. Opposing the four photosensitive drums 1, an intermediate transfer belt 31 is disposed as an intermediate transfer body for transferring the toner image (developer image) on the photosensitive drum 1 to the recording material 12. The intermediate transfer belt 31, which is formed of an endless belt as an intermediate transfer body, contacts all the photosensitive drums 1 and circulates (rotates) in the direction of arrow B (counterclockwise) shown in FIG. 1. The intermediate transfer belt 31 is stretched over a driving roller 31a and a driven roller 31b as a plurality of support members. On the inner peripheral surface side of the intermediate transfer belt 31, four primary transfer rollers 32 as primary transfer means are arranged in parallel so as to face each photosensitive drum 1. A bias of a polarity opposite to the normal charging polarity of the toner is applied to the primary transfer rollers 32 from a primary transfer bias power source (high voltage power source) as a primary transfer bias application means (not shown). As a result, the toner image on the photosensitive drum 1 is transferred (primary transfer) onto the intermediate transfer belt 31.

Also, a secondary transfer roller 33 is arranged on the outer peripheral surface side of the intermediate transfer belt 31 as a secondary transfer means. A bias of the opposite polarity to the normal charging polarity of the toner is applied to the secondary transfer roller 33 from a secondary transfer bias power supply (high voltage power supply) as a secondary transfer bias application means (not shown). As a result, the toner image on the intermediate transfer belt 31 is transferred (secondarily transferred) to the recording material 12. For example, when a full-color image is formed, the above-mentioned process is performed sequentially in the image forming units SY, SM, SC, and SK, and the toner images of each color are sequentially superimposed on the intermediate transfer belt 31 and primarily transferred. Thereafter, the recording material 12 is transported to the secondary transfer unit in synchronization with the movement of the intermediate transfer belt 31. Then, the four-color toner images on the intermediate transfer belt 31 are secondarily transferred collectively onto the recording material 12 by the action of the secondary transfer roller 33 that is in contact with the intermediate transfer belt 31 via the recording material 12. The recording material 12 to which the toner image has been transferred is transported to the fixing device 34 as a fixing means. The toner image is fixed to the recording material 12 by applying heat and pressure to the recording material 12 in the fixing device 34. The image forming apparatus 100 also has a control unit 101. The control unit 101 controls the entire image forming apparatus 100 and also acquires various information from the host device via the input/output I/F 114.

[Drum Cartridge]
Next, the configuration of the drum cartridge 210 will be described. FIG. 2 is a cross-sectional (main cross-sectional) view of the drum cartridge 210 seen along the longitudinal direction (rotation axis direction) of the photosensitive drum 1. The photosensitive drum 1 is rotatably attached to the drum cartridge 210 via a bearing (not shown). The photosensitive drum 1 is driven to rotate in the direction of the arrow A shown in FIG. 2 in response to an image forming operation by receiving a driving force from a driving motor M210 as a driving means. In the first embodiment, the drum cartridge 210 has a diameter of Φ24 mm and rotates at 200 mm/sec. In addition, the drum cartridge 210 is provided with a charging roller 2 and a cleaning blade 6 as a cleaning member (contact member) formed of an elastic body so as to contact the surface of the photosensitive drum 1 in a rotating state. A bias sufficient to place any charge on the photosensitive drum 1 is applied to the charging roller 2 from a charging bias power source (high voltage power source) as a charging bias application means (not shown). In the first embodiment, the bias applied is set so that the potential (charging potential: Vd) on the photosensitive drum 1 is −500 V. A laser beam 35 is emitted from a scanner unit 30 based on image information, and an electrostatic image (electrostatic latent image) is formed on the photosensitive drum 1 .

The cleaning blade 6 is formed by a rubber blade 6a supported by a cleaning support metal plate 6b, and the rubber blade 6a and the cleaning support metal plate 6b are integrally formed. For example, the rubber blade 6a is made of urethane rubber having a thickness of 2 mm and an MD-1 hardness of 60 to 80° under a 23°C environment. The cleaning blade 6 is fixed to the drum cartridge frame 11, and is arranged so that the tip of the rubber blade 6a abuts against the photosensitive drum 1. The cleaning blade 6 scrapes off toner that has not been transferred to the intermediate transfer belt 31 and remains on the surface of the photosensitive drum 1 with the tip of the free end of the rubber blade 6a, removing the toner from the surface of the photosensitive drum 1. The drum cartridge 210 is also provided with a non-volatile memory (hereinafter referred to as "O memory") m1 as a first memory. The O memory m1 stores information according to the amount of use of the drum cartridge 210.

The information according to the usage of the drum cartridge 210 is information related to the amount of operation, such as the cumulative number of rotations and cumulative rotation time of the photosensitive drum 1. The information according to the usage of the drum cartridge 210 may be a value obtained by dividing the information related to the amount of operation of the photosensitive drum 1 by a predetermined life value related to the photosensitive drum 1. It may also be a percentage value obtained by multiplying this value by 100. The predetermined value related to the photosensitive drum 1 is, for example, the number of rotations or rotation time of the photosensitive drum 1, and is a value set based on the life of the photosensitive drum 1 (a value corresponding to the amount of use of the drum cartridge 210 when the replacement prompt message is displayed). The information according to the usage of the drum cartridge 210 may also be a value obtained by subtracting the cumulative number of rotations or cumulative rotation time of the photosensitive drum 1 from the predetermined value related to the photosensitive drum 1. The information related to the amount of operation, such as the cumulative number of rotations and cumulative rotation time of the photosensitive drum 1, can be substituted with parameters that have a certain degree of correlation therewith, such as the number of printed sheets or the amount of toner used.

The control unit 101 can then obtain the amount of usage, such as how much the drum cartridge 210 has been used and how much it has operated, based on the information stored in O memory m1. In other words, information related to the amount of operation, such as the cumulative rotation time and cumulative number of rotations of the photosensitive drum 1, or information corresponding to the amount of usage of the drum cartridge 210 corrected by the control unit 101 based on information in place of this, is written by the control unit 101 to O memory m1.

[Developing Cartridge]
Next, the configuration of the developing cartridge 200 to be mounted on the image forming apparatus will be described. FIG. 3 is a cross-sectional (main cross-sectional) view of the developing cartridge 200 as viewed along the longitudinal direction (rotation axis direction) of the developing roller 4. The developing cartridge 200 is composed of a developing chamber 20a and a developer storage chamber 20b, and the developer storage chamber 20b is disposed vertically below the developing chamber 20a. The developer storage chamber 20b stores toner 9 as a developer. Silica particles having a particle size of 20 nm are added to the surface of the toner 9 as a toner external additive (external additive particles). The normal charging polarity of the toner 9 is negative, and the following description will be given of a case where a negatively charged toner is used as the toner 9. However, the toner 9 is not limited to a negatively charged toner. The developer storage chamber 20b is provided with a developer transport member 21 for transporting the toner 9 to the developing chamber 20a, and the developer transport member 21 rotates in the direction of the arrow G shown in FIG. 3 to transport the toner 9 to the developing chamber 20a.

The developing chamber 20a is provided with a developing roller 4 as a developer carrier that contacts the photosensitive drum 1 and rotates in the direction of the arrow D shown in FIG. 3 by receiving the driving force of a driving motor M200 as a developing drive means. In the first embodiment, the developing roller 4 and the photosensitive drum 1 rotate so that their surfaces move in the same direction at the opposing portion (contact portion), and the developing roller 4 rotates 150% faster than the photosensitive drum 1. A bias sufficient to develop the electrostatic latent image on the photosensitive drum 1 into a toner image and make it visible is applied to the developing roller 4 from a developing bias power source (high voltage power source) as a developing bias application means (not shown). Inside the developing chamber 20a, a toner supply roller (hereinafter simply referred to as a "supply roller") 5 is arranged to supply the toner 9 transported from the developer storage chamber 20b to the developing roller 4. Also, inside the developing chamber 20a, a toner amount regulating member 8 is arranged to regulate the coat amount of the toner 9 on the developing roller 4 supplied by the supply roller 5 and to impart a charge. The developing cartridge 200 is provided with a non-volatile memory (hereinafter referred to as "DT memory") m2 as a second memory. The DT memory m2 stores information according to the amount of usage of the developing cartridge 200.

Information according to the usage amount of the developing cartridge 200 is, for example, information related to the amount of operation of the developing cartridge, such as the cumulative number of rotations of the developing roller 4 or the cumulative time.

Even with the same development roller drive amount, the information corresponding to the usage of the development cartridge 200 differs depending on (1) the operating mode of the image forming apparatus when the development roller 4 rotates, (2) the cumulative amount of toner used/the amount of toner remaining, (3) the operating environment, (4) the page printing rate, etc. In other words, the CPU 111 corrects the drive amount of the development roller 4 (cumulative number of rotations, cumulative time) based on the information of (1) to (4), and information corresponding to the usage of the development cartridge 200 is obtained. The information corresponding to the usage of the development cartridge 200 obtained here can essentially be regarded as the degree of deterioration of the toner stored in the development cartridge 200.

Here, the operating modes of the image forming device when the developing roller 4 rotates (1) include a pre-rotation operation, which is a preparatory operation before image formation, an image forming operation to form an image on a recording medium, and a post-rotation operation, which is a preparatory operation after image formation.

The CPU 111 also uses (2) the cumulative amount of toner used/the amount of toner remaining when weighting the amount of operation of the developing cartridge. For example, if the cumulative amount of toner used is high or the amount of toner remaining is low for one developing cartridge 200, the CPU 111 overestimates the amount of operation of the developing cartridge. The CPU 111 may also correct the information corresponding to the amount of usage of the developing cartridge 200 itself so as to overestimate the information corresponding to the amount of usage of the developing cartridge 200, rather than the amount of operation of the developing cartridge. The CPU 111 may also correct the information corresponding to the amount of operation of the developing cartridge and the amount of usage of the developing cartridge 200.

Furthermore, for (3) and (4), the CPU 11 corrects the information according to the amount of operation of the developing cartridge and/or the amount of usage of the developing cartridge 200 depending on the operating environment and page print rate of the image forming apparatus. For example, when the operating environment is a low temperature and low humidity environment such as a temperature of 15°C and humidity of 10%, or a high temperature and high humidity environment such as a temperature of 30°C and humidity of 80%, the amount of operation of the developing cartridge is estimated to be larger than in a reference environment (for example, a temperature of 23°C and humidity of 50%). Also, the lower the page print rate, the more toner is used, and the larger the amount of usage of the developing cartridge is estimated. In this case, the print rate is estimated for each page.

In this way, the CPU 111 can obtain information according to the amount of usage of the developing cartridge 200 depending on various conditions, and in some cases, can appropriately display a message urging replacement even if there is toner remaining in the developing cartridge 200.

Furthermore, the amount of toner used is the amount of toner 9 that has been used out of the toner 9 contained in the developing cartridge 200. The amount of remaining toner is the amount of toner 9 that remains out of the toner 9 contained in the developing cartridge 200. The amount of toner used may be found by subtracting the amount of remaining toner from the amount of toner in the developing cartridge 200 before use is started. The amount of remaining toner may be found by subtracting the amount of toner used from the amount of toner in the developing cartridge 200 before use is started.

Here, the information according to the usage of the developing cartridge 200 may be the value itself corrected by the CPU 111, or may be a value obtained by dividing the value by a predetermined life value. It may also be a percentage value obtained by multiplying the value by 100. The predetermined value related to the developing roller 4 is, for example, the number of rotations or rotation time of the developing roller 4, and is a value set based on the life of the developing roller 4 (a value according to the usage of the developing cartridge 200 when the replacement prompt message is displayed). The information according to the usage of the developing cartridge 200 may be a value obtained by dividing the amount of toner used by the amount of toner in the developing cartridge 200 when it is new. It may also be a percentage value obtained by multiplying the value by 100. Furthermore, the information according to the usage of the developing cartridge 200 may be a value obtained by dividing the amount of toner remaining by the amount of toner in the developing cartridge 200 when it is new. It may also be a percentage value obtained by multiplying the value by 100. In this way, information related to the amount of operation, such as the cumulative number of rotations and cumulative rotation time of the developing roller 4, can be replaced by parameters that have a certain degree of correlation therewith. In addition, it can also be substituted by, for example, the number of printed sheets.

The control unit 101 can obtain information corresponding to the usage amount of the developing cartridge 200 based on the information stored in the DT memory m2. In other words, the information corresponding to the usage amount of the developing cartridge 200 obtained by correcting the drive amount (accumulated number of rotations, accumulated time) of the developing roller 4 is written by the control unit 101 to the DT memory m2.

[Block Diagram]
Next, the control configuration of the image forming apparatus 100 will be described with reference to FIG. 4. FIG. 4 is a control block diagram in the first embodiment. The control unit 101 has a CPU (Central Processing Unit) 111, which is a central element for performing arithmetic processing, a memory such as a ROM 112 and a RAM 113, which are storage means, and an input/output I/F 114 for inputting and outputting information to and from peripheral devices. The CPU 111 is also called a processor. The CPU 111 is not limited to a single processor, and may be a multi-processor configuration. The CPU 111 performs various controls of the control unit 101 using the ROM 112 and the RAM 113. The RAM 113 stores the detection results of the sensors, the calculation results, and the like, and the ROM 112 is a rewritable non-volatile storage means, and stores a control program, a data table obtained in advance, and various variables.

The control unit 101 is a control means that comprehensively controls the operation of the image forming device 100, and each control object in the image forming device 100 is connected via the input/output I/F 114.

The image forming unit 510 has a motor driving unit 511, a high-voltage power supply 512, an exposure control unit 513, and a contact/separation unit 514, and controls the motor driving unit 511, the high-voltage power supply 512, the exposure control unit 513, and the contact/separation unit 514. Note that the control unit 101 may also control the motor driving unit 511, the high-voltage power supply 512, the exposure control unit 513, and the contact/separation unit 514.

The motor drive unit 511 includes various motors and is a power source for rotating the polygon scanner, the photosensitive drum 1, the developing roller 4, etc., and operates based on control signals from the control unit 101 or the image forming unit 510.

The high-voltage power supply 512 is a power supply that applies high voltage to the photosensitive drum 1, charging roller 2, developing roller 4, primary transfer roller 32, secondary transfer roller 33, fixing device 34, etc.

The exposure control unit 513 transmits a signal indicating the amount of light of the laser light 35 irradiated onto the photosensitive drum 1 to the scanner unit 30.

The contact/separation unit 514 switches between a contact position where the developing roller 4 contacts the photosensitive drum 1 and a separation position where the developing roller 4 is separated from the photosensitive drum 1. The contact/separation unit 514 also switches between a contact position where the intermediate transfer belt 31 contacts the photosensitive drum 1 and a separation position where the intermediate transfer belt 31 is separated from the photosensitive drum 1.

The environmental sensor 102 is a sensor provided in the image forming apparatus 100 for measuring temperature and humidity, and transmits data related to temperature and humidity to the control unit 101. Data communication is performed between the control unit 101 and the O memory m1 via the drum memory communication unit 515, and data communication is performed between the control unit 101 and the DT memory m2 via the development memory communication unit 516. The O memory m1 and the DT memory m2 are used by the control unit 101 when determining information according to the usage of the drum cartridge 210 and the development cartridge 200. Data stored in the DT memory m2 is sent to the control unit 101 via the development memory communication unit 516. The control unit 101 notifies the user of a protection warning for the drum cartridge 210 based on information on the usage of the O memory m1 and the DT memory m2. The notification to the user is performed by a display/operation panel (a display device provided in the image forming apparatus 100, or a device having a display) as a notification device. The control unit 101 also controls the sending and receiving of various electrical information signals, drive timing, etc., and is responsible for the flowchart processing described below.

[Process leading up to the drum cartridge protection warning notification]
The process of displaying (notifying) a message prompting replacement of the developing cartridge 200 in the first embodiment will be described with reference to the flowchart in Fig. 5(a), and the process of notifying a protection warning for the drum cartridge 210 will be described with reference to the flowchart in Fig. 5(b). In the flowcharts in Fig. 5(a) and (b), processing is performed for each of the imaging units SY, SM, SC, and SK.

For example, when information according to the amount of usage of the developing cartridge 200 exceeds the replacement reminder threshold, a replacement reminder message is displayed on the operation/display panel 51 (alarm device). Upon receiving this notification, the user can select whether or not to continue the image formation operation. Below, the process leading up to the display of the replacement reminder message is explained using the flowchart in FIG. 5(a).

After the image forming device 100 is turned on or the cartridge replacement door is opened and closed, when the image forming device 100 becomes operable, the flow shown in FIG. 5(a) starts (S1).

The control unit 101 then communicates with the O memory m1 mounted on the drum cartridge 210 via the drum memory communication unit 515. The control unit 101 (CPU 111) then acquires information (second information) corresponding to the amount of usage of the drum cartridge 210 from the O memory m1 of each of the imaging units SY, SM, SC, and SK (S2). The information corresponding to the amount of usage of the drum cartridge 210 is as described above.

The control unit 101 also communicates with the DT memory m2 mounted in the developing cartridge 200 through the developing memory communication unit 516, and acquires information (first information) corresponding to the usage amount of the developing cartridge 200 from the DT memory m2 of each of the imaging units SY, SM, SC, and SK (S3). The information corresponding to the usage amount of the developing cartridge 200 is also as described above.

The control unit 101 then determines whether the information corresponding to the amount of usage acquired for each color drum cartridge 210 and each color developing cartridge 200 exceeds the replacement prompt threshold. Note that it is assumed that the replacement prompt threshold for the developing cartridge 200 is smaller than the replacement prompt threshold for the drum cartridge 210. This is because it is assumed that two or more developing cartridges 200 are used for one drum cartridge 210.

Then, in step S5, the control unit 101 causes the operation/display panel 51 to display a replacement prompt message for the cartridge whose information according to the amount of usage exceeds the replacement prompt threshold. The control unit 101 causes the notification device to issue a notification regarding replacement prompt for the drum cartridge 210 (photosensitive drum 1) based on the information (second information) according to the amount of usage of the drum cartridge 210 from the O memory m1. The control unit 101 also causes the notification device to issue a notification regarding replacement prompt for the developer cartridge 210 (developer roller 4) based on the information (first information) according to the amount of usage of the developer cartridge 200 from the DT memory m2. Here, the notification regarding replacement prompt may be a message informing the user that the unit has reached the end of its life, or a message directly prompting replacement. Whether directly or indirectly, as long as the content prompts replacement, it functions as a replacement prompt.

The main reason why the message urging replacement is displayed in step S5 of FIG. 5(a) is due to deterioration of the toner 9 in the developing cartridge 200 caused by repeated rubbing, and it is assumed that there is still toner 9 remaining. In this case, although uneven halftone images may occur due to deterioration of the toner 9, there is no major problem with the output of text images such as characters, so the user can select whether to continue the image formation operation. Then, when the user instructs via the operation/display panel 51 to continue the image formation operation, the flowchart of FIG. 5(b) is executed (S11). The flowchart of FIG. 5(b) will be described below. Note that the processes of steps S12 and S13 are similar to steps S2 and S3 of FIG. 5(a), so detailed explanations will be omitted.

The control unit 101 reads out from the ROM 112 a table of the protection warning timing for the drum cartridge 210 and references it (S14). The contents of the table are as shown in Table 1, which will be described later. The information acquired by the control unit 101 in S12 corresponds to one of the vertical axes of Table 1, and the information acquired by the control unit 101 in S13 corresponds to one of the horizontal axes of Table 1.

When the combination of information according to the usage amount of the drum cartridge 210 and the developing cartridge 200 in the imaging units SY, SM, SC, and SK is determined by the table referenced in S14 to be the timing to issue a protection warning for the drum cartridge 210 (S5: YES), the control unit 101 temporarily halts the image forming operation (S16). For example, when it is the timing to issue a protection warning for the drum cartridge 210 for the imaging unit SY, the control unit 101 temporarily halts the image forming operation including the imaging units SM, SC, and SK that have not yet passed the timing to issue a protection warning.

On the other hand, if the conditions for issuing a protection warning for the drum cartridge 210 are not met for each of the imaging units SY, SM, SC, and SK (S15: NO), the control unit 101 returns the process to S12 after each image formation operation is completed, and repeats the same process below.

Then, for the imaging unit for which the drum cartridge 210 protection warning timing has arrived, the control unit 101 notifies the display/operation panel 51 of a warning regarding protection of the drum cartridge 210 (S17).

Here, examples of the display/operation panel 51 include a display attached to the image forming apparatus 100, and the displays of the image forming apparatus 100 and a personal computer. In addition, an example of a warning display related to protection of the drum cartridge 210 of the imaging unit SY is a display such as "The drum cartridge (yellow) may be damaged. Please replace the developing cartridge (yellow)."

Note that before issuing the drum cartridge 210 protection warning in step S17, the control unit 101 has already executed the flowchart in FIG. 5(a) to cause the notification device to issue a notification regarding the promotion to replace each cartridge. In other words, the processing in step S17 is performed after issuing a notification regarding the promotion to replace each cartridge. Once the drum cartridge protection warning is displayed, the flow in FIG. 5 ends (S18).

As described above, the control unit 101 refers to the table shown in Table 1, for example, as a table of timing for reporting a protection warning for the drum cartridge 210. The table in Table 1 is stored, for example, in the ROM 112, the O memory m1, or the DT memory m2. Note that the usage amount of the developing cartridge 200 is displayed as 0% for a new cartridge before it reaches the end of its life, 100% when the usage reaches the threshold for a replacement reminder, and a value of 100% or more after it reaches the end of its life. Here, if the usage amount exceeds 100%, it means that the toner has deteriorated beyond the expected life, and in Table 1, the words "degree of deterioration" are used for the items on the vertical and horizontal axes.

[Drum Cartridge Protection Warning Notification Table]
The deterioration degree of the drum cartridge 210 on the vertical axis is a percentage obtained by dividing the information acquired by the control unit 101 in S12, the cumulative number of rotations or the cumulative rotation time of the photosensitive drum 1, by a predetermined value related to the photosensitive drum 1. The deterioration degree of the developing cartridge 200 at the time of the advance notice is a percentage obtained by dividing the information acquired by the control unit 101 in S13, the cumulative number of rotations or the cumulative rotation time of the developing roller 4, by a predetermined value related to the developing roller 4. The deterioration degree of the developing cartridge 200 may be a value expressed as a percentage by calculating the number of frictions (degree of damage) received from the members related to the toner 9 from the information on the cumulative number of rotations of the developing roller and the amount of toner used. The vertical and horizontal axes of the drum cartridge protection warning notification table are not limited to percentage values, and may be appropriately replaced with any information according to the amount of use described above.

For example, if the usage of the drum cartridge 210 is between 0% and 33% and the usage of the developer cartridge 200 is 161% or more, a protection warning for the drum cartridge 210 is issued. Also, if the usage of the drum cartridge 210 is between 67% and 100% and the usage of the developer cartridge 200 is 121% or less, a protection warning for the drum cartridge 210 is issued. As shown in Table 1, the timing of the protection warning is made earlier as the usage of the drum cartridge 210 increases and as the usage of the developer cartridge 200 increases.

Here, an evaluation was conducted regarding the occurrence of vertical streak images due to damage to the cleaning members when the drum cartridge 210 and the developing cartridge 200 were used at various amounts. As a common condition, for each amount of use of the drum cartridge 210 and the developing cartridge 200, a horizontal line image with a print rate of 1% for each color was used as a durability image, and 2,000 sheets were printed. As an evaluation image for cleaning performance, a halftone image with a print rate of 25% for each color was printed, and image defects (vertical streaks) were confirmed. The environment in which the image forming device 100 was installed was a temperature of 23°C and a humidity of 50%.

In Table 2, "◯" means that no vertical streak images occurred, and "×" means that vertical streak images occurred. As shown in Table 2, if the usage amount of each of the drum cartridge 210 and the developing cartridge 200 was before the drum cartridge 210 protection warning was issued, no vertical streak images occurred. However, when evaluating the timing after the drum cartridge 210 protection warning was issued, vertical streak images occurred. The cleaning blade 6 at the position where the vertical streak images occurred had chipped blade edges.

As described above, by using the configuration of Example 1, even if the developer cartridge 200 continues to be used after a replacement reminder, a protection warning for the drum cartridge 210 can be issued at an appropriate time. This makes it possible to prevent vertical streak images caused by damage to the cleaning blade 6.

In this embodiment, when the developing unit continues to be used after a replacement reminder, image defects such as toner fogging can be prevented by correcting the amount of wear on the photosensitive drum of the latent image unit. Furthermore, toner fogging can be prevented more accurately by controlling the charging bias based on the amount of wear on the drum after the correction. Note that the image forming apparatus, drum cartridge, developing cartridge, and block diagram used in this embodiment are the same as those in embodiment 1, so detailed explanations are omitted.

In addition, if the development unit continues to be used after the end of its life, even if the cleaning blade does not break, the speed at which the dielectric layer on the surface of the photosensitive drum is worn away may increase due to increased frictional resistance between the photosensitive drum and the cleaning blade. In this case, an error occurs in the calculation of the remaining thickness of the dielectric layer on the photosensitive drum, which in turn causes an error in the bias applied to the charging device, resulting in image defects such as toner fogging. Therefore, if the development unit continues to be used after the end of its life, it is necessary to correct the calculation of the speed at which the dielectric layer on the surface of the photosensitive drum is worn away accordingly.

[Process for correcting scraping amount of drum cartridge]
The process up to the drum scraping amount correction control of the drum cartridge 210 in the second embodiment will be described with reference to the flowchart of Fig. 7. Note that the flowchart of Fig. 5 described in the first embodiment is performed separately from the flowchart of Fig. 7. That is, the flowchart of Fig. 7 shows the process performed by the control unit 101 for the same combination of the developer cartridge 200 and the drum cartridge after the notification device 51, which notifies the developer cartridge 200 to promote replacement, performs the process according to the flow of Fig. 5.

After the image forming device 100 is turned on or the cartridge replacement door is opened and closed, the flow shown in FIG. 7 starts when the image forming device 100 is in an operable state (S201).

First, the control unit 101 communicates with the O memory m1 installed in the drum cartridge 210 via the drum memory communication unit 515, and obtains information corresponding to the usage amount of the drum cartridge 210 from the O memory m1 of each of the imaging units SY, SM, SC, and SK (S202).

The control unit 101 then communicates with the DT memory m2 installed in the developing cartridge 200 via the developing memory communication unit 516, and acquires information corresponding to the usage amount of the developing cartridge 200 from the DT memory m2 of each of the imaging units SY, SM, SC, and SK (S203). The information corresponding to each usage amount is as described in the first embodiment. A detailed description will be omitted here.

Next, the control unit 101 reads out from the ROM 112 a table relating to the amount of surface wear of the photosensitive drum of the drum cartridge 210 and refers to it (S204). The amount of surface wear of the photosensitive drum is calculated using formula (1) described below.

The control unit 101 determines whether the information according to the usage amount of the developing cartridge 200 is the timing after the replacement prompt threshold is reached based on the information acquired in S203 in the imaging units SY, SM, SC, and SK. The information according to the usage amount of the drum cartridge 210 and the information according to the usage amount of the developing cartridge 200 are as described in Example 1.

If the control unit 101 determines YES in S205, the control unit 101 corrects the amount of drum surface wear calculated in S204 in accordance with the information on the amount of usage of the developing cartridge (S206). The control unit 101 subtracts this corrected amount of drum surface wear from the initial drum film thickness to calculate the corrected drum film thickness.

For example, if the information according to the usage amount of the developing cartridge of the imaging unit SY reaches the developing cartridge replacement prompt threshold, the control unit 101 corrects the amount of wear on the drum surface. The contents of the correction table are as shown in Table 3, which will be described later. The information acquired by the control unit 101 in S203 corresponds to one of the values on the vertical axis of Table 3.

This step S206 is also performed when the same combination of the developing cartridge 200 and drum cartridge 210 that was the subject of the notification in the flowchart of FIG. 5 is the subject of the judgment. In this case, the control unit 101 refers to the table in Table 3 described below and estimates the amount of drum surface wear for a given amount of usage of the developing unit 200 after the notification regarding the replacement promotion to be greater than the amount of drum surface wear for the same given amount of usage before the notification. In other words, the control unit 101 uses a larger coefficient value for the given amount of usage of the developing unit 200 after the replacement promotion of the developing unit, and calculates the amount of drum surface wear for the amount of usage of the developing unit 200. Note that the given amount of usage can be, for example, the number of rotations of the developing roller 4, the driving time of the developing drum unit 200, or information that is correlated with them, such as the number of printed sheets.

Then, the control unit 101 sets the charging bias based on the corrected drum film thickness that reflects the corrected amount of wear (S207). For example, in the drum film thickness of the above-mentioned drum cartridge 210, assume that the corrected actual drum film thickness has been worn down by about 1 μm compared to before the correction. In this case, the control unit 101 applies a charging bias that is increased by about 10 V based on the corrected drum film thickness, and sets it so that the white background potential (Vd) on the drum surface is the same.

The setting of the charging application bias in step S207 may be performed by having the control unit 101 refer to a table of drum surface abrasion amounts and charging application bias values prepared in advance. In this case, in step S207, the control unit 101 does not need to take the trouble of calculating the drum film thickness by subtracting the corrected drum surface abrasion amount from the initial drum film thickness.

Returning to the explanation of the flowchart, the image forming apparatus 100 then transitions to image forming operation and executes printing based on the bias settings changed by the control unit 101.

On the other hand, if the replacement prompt threshold for the developing cartridge 200 has not been reached in each of the imaging units SY, SM, SC, and SK (S205: NO), the control unit 101 does not make any particular correction to the amount of wear. In other words, the control unit 101 sets the charging application bias based on the drum film thickness due to the amount of wear on the drum surface without correction.

Then, the control unit 101 transitions to image formation operation with the set charging application bias and executes printing. Then, when the printing operation ends, the flow in FIG. 7 ends (S208).

The control unit 101 refers to the table shown in Table 1 of Example 1, for example, as a table of the timing for issuing a protection warning for the drum cartridge 210. Note that with regard to the degree of deterioration (amount of usage) of the developing cartridge 200, a new product before the end of its life is displayed as 0%, the amount of usage at the end of its life is displayed as 100%, and after the end of its life is displayed as a value of 100% or more. The same applies to the degree of deterioration of the drum cartridge with respect to Table 1.

[Drum scrape correction table]
As already described in the first embodiment, the information according to the usage of the drum cartridge 210 and the developing cartridge 200 is derived from the information of the cumulative number of rotations or the cumulative rotation time of each. Here, the amount of surface wear of the photosensitive drum will be explained. The surface layer of the photosensitive drum is formed by laminating at least a conductive layer, a charge generation layer as a photosensitive layer, and a charge transport layer in this order on a conductive support. The photosensitive drum used this time is formed by laminating a conductive layer, an undercoat layer that prevents charge injection, a charge generation layer as a photosensitive layer, and a charge transport layer that transports charges in this order on a conductive support. The film thickness is the distance from the surface of the conductive support to the surface of the charge generation layer. The amount of surface wear of the drum can generally be calculated from the following formula (1).
K = αX + βY + γZ (1)

Here, α is the drum surface layer wear coefficient per unit time for the idle rotation of the photosensitive drum (when no charge is applied and no development contact is made), and X indicates the operation time of that operation. β is the drum surface layer wear coefficient per unit time for the rotation of the photosensitive drum (when no development contact is made) in a state where a charge is applied, and Y indicates the operation time of that operation. γ is the drum surface layer wear coefficient per unit time for the rotation of the photosensitive drum when a charging voltage is applied and development contact is made, and Z indicates the operation time. The control unit 101 calculates the amount of drum surface layer wear from these three coefficients (α, β, γ) and each operation time (X, Y, Z). The actual film thickness is calculated from the following formula (A).
Drum film thickness = initial film thickness - drum scraping amount (K) ... (A)

The calculated values are stored in the drum film thickness information in O memory m1 in the drum cartridge 210, making it possible to calculate the remaining film thickness at any time.

In this embodiment 2, the wear coefficient is corrected when the developing cartridge 200 continues to be used after reaching the end of its life. The amount of drum correction for the degree of deterioration (amount of usage) of each developing cartridge is explained using the table of Table 3. For example, the control unit 101 refers to the table of Table 3 when calculating the drum wear amount of the drum cartridge 210. The table of Table 3 is stored, for example, in the ROM 112, the O memory m1, or the DT memory m2. The display of the degree of deterioration (amount of usage) of the developing cartridge 200 is the same as in the first embodiment.

As in the first embodiment, when the usage status of the developer cartridge reaches the replacement reminder threshold (usage reaches 100%), a notification that the cartridge has reached the end of its life is displayed on the display/operation panel 51. Upon receiving this notification, the user can choose whether to continue the image formation operation. In this case, although uneven halftone images may occur due to deterioration of the toner 9, there is no major problem with the output of text images such as letters, so the user can choose whether to continue the image formation operation.

Here, as shown in Table 3, even after the usage status of the developer cartridge reaches the replacement reminder threshold, drum wear correction is performed according to information (degree of deterioration) corresponding to the amount of usage of the developer cartridge. As shown in the table, the degree of correction of the drum wear of the drum cartridge increases as the usage (degree of deterioration) of the developer unit increases and as the usage (degree of deterioration) of the drum cartridge increases. By correcting the amount of drum wear based on Table 3, the actual amount of drum wear can be accurately grasped, making it possible to apply an appropriate charging bias.

An evaluation was conducted on the occurrence of toner fogging in images according to the amount of development cartridge usage shown in Table 4. As evaluation conditions, the drum cartridge 210 was used at 100%, and 5,000 sheets were printed with a horizontal line image of 1.0% printing rate for each color. To evaluate the toner fogging, a solid white image was printed and toner fogging on the image was confirmed. The image forming apparatus 100 was installed in a low-temperature, low-humidity environment with a temperature of 15°C and a humidity of 10%, and the test was conducted.

As a comparative example, Table 4 also shows the evaluation results under conditions where the drum scraping correction amount was not taken into account. "○" means that no toner fog images occurred, "△" means that the fog on the drum was worsened, but there was no problem with the solid white image. "×" means that toner fog occurred on the solid white image.

As can be seen from these results, there were no problems with either of the results if the usage status of the developer cartridge 200 had not reached the replacement reminder threshold. However, when evaluated after the threshold was reached, a toner fog image occurred. Confirmation and examination at the time when the toner fog image occurred revealed that Vd had become low due to a deviation in the charging bias, and the contrast with the developing bias (hereinafter referred to as Vback) tended to be narrower than the desired setting. Note that Vback refers to the difference between Vd (the potential of the white background on the drum surface) and the developing bias (the bias applied to the developing roller).

Figure 8 shows the Vback dependency of toner fog after the usage status of the developer cartridge reaches the replacement reminder threshold. If Vback is set based on a normal latent image setting, it will be set as A in the figure, and toner fog will not occur. As explained above, by performing drum abrasion correction, it was possible to suppress the occurrence of toner fog. As a comparative example, under conditions that do not take into account the amount of drum abrasion, a deviation of up to about 1 μm was confirmed, depending on the number of sheets passed. It was found that this was due to a deviation from the actual drum film thickness, resulting in setting B in the figure.

[Electric potential characteristics of the surface layer of the drum cartridge]
Generally, when the surface layer of the drum is worn away and becomes thinner, the light area potential (Vd) of the drum and the dark area potential (VL) after the latent image tend to increase even if the same charging bias is applied. In addition, Vd down due to dark attenuation occurs during the movement from the charging position to the developing position. This can be explained by the relationship of electrostatic capacitance.

The capacitance relation is shown in equation (2).
Q = CV = ε0εγ × S / d (2)
Q: charge (C), C: static electricity (F), V: electric potential (V), ε0εγ: dielectric constant, S: area (m ² ).
d: Distance (m).

As a result, the charge Q is proportional to the potential V and inversely proportional to the distance d. In other words, the relationship between capacitance and charging current is inversely proportional to the surface film thickness of the drum.

Here, the relationship between the potential of the drum surface layer thickness and the fogging characteristics will be explained using Figure 9. The horizontal axis is the drum surface layer thickness (μm), and the vertical axis is toner fogging (%). The solid line shows the effect of toner fogging when Vd is set to -600V, while dashed lines 1 and 2 show the tendency when Vd is set to -500V and -400V, respectively. As can be seen from Figure 9, the toner fogging rapidly worsens as the drum surface layer thickness decreases beyond the 10μm threshold. Furthermore, it is known that the tendency is more pronounced when the absolute value of the Vd potential is higher. In other words, when the surface layer thickness is 10μm or less, image defects such as toner fogging are more likely to occur.

Based on these experiences, the drum surface layer thickness of the drum cartridge is designed to reach the end of the drum's life (time to prompt replacement) when it reaches approximately 10 to 11 μm. However, once the usage of the developer cartridge reaches the threshold for prompting replacement, the amount of drum wear increases with the same rotation of the photosensitive drum, so the amount of wear in the drum layer thickness must be corrected.

As described above, even if the user continues to use the developer cartridge 200 whose usage has reached the replacement prompt threshold, the amount of drum wear of the drum cartridge 210 can be corrected. This allows the control unit 101 (CPU 11) to select and control an appropriate charging application bias setting according to the drum film thickness after correction, thereby suppressing the occurrence of toner fogging.

[Modification]
The imaging units SY, SM, SC, and SK of the image forming apparatus 100 in the first and second embodiments are configured by the drum cartridge 210 and the developing cartridge 200, but are not limited thereto. The present invention can also be applied to a so-called toner supply system in which the toner container containing the toner 9 among the components of the developing cartridge 200 is a separate unit (toner cartridge). For example, in the case of a toner supply system, a toner cartridge (developer unit) that contains the toner 9 and is detachable from the main body of the image forming apparatus 100 is separated from the developing cartridge 200. In the case of a toner supply system, the same effect can be obtained by changing the condition of the information according to the usage amount of the developing cartridge 200 used for determining the protection warning notification to the condition of the information according to the usage amount of the toner cartridge. In this case, a non-volatile memory as the DT memory m2 or the third memory is provided in the toner cartridge, and information according to the usage amount of the toner cartridge is stored in the DT memory m2 or the third memory provided in the toner cartridge.

In addition, in the first and second embodiments, the drum cartridge 210 is provided with the O memory m1, and the developer cartridge 200 is provided with the DT memory m2. However, the present invention is not limited to this configuration. The image forming apparatus 100 may have the O memory m1 and the DT memory m2 in its main body. The image forming apparatus 100 may have a third memory in its main body. In this case, the O memory m1 and the DT memory m2 are respectively stored with a drum cartridge identifier and a developer cartridge identifier that can identify the individual drum cartridge 210 and developer cartridge 200. The control unit 101 associates the identifiers with the information corresponding to the respective amounts of usage, and stores the information in the third memory in the main body of the image forming apparatus 100, and manages the information in the same manner as described above.

1 Photoconductor drum 2 Charging roller 4 Developing roller 5 Toner supply roller 6 Cleaning blade (contact member)
9 Toner 11 Drum cartridge frame 31 Intermediate transfer belt 34 Fixing device 100 Image forming apparatus 101 Control unit 102 Temperature sensor (environment detection means)
200 Developing cartridge (developing unit)
210 Drum cartridge (latent image unit)
m1 O memory (first memory)
m2 DT memory (second memory)

Claims (14)

An image forming apparatus in which a latent image unit and a developing unit are detachably attached to a main body of the apparatus,
The latent image unit includes:
a rotatable image carrier on which an electrostatic latent image is formed;
a cleaning member that contacts the image carrier to remove developer from the surface of the image carrier;
The developing unit comprises:
a developer carrier for developing the electrostatic latent image formed on the image carrier with a developer image;
Furthermore, the image forming apparatus
A control unit;
a notification device that notifies the user of a promotion for replacing the developing unit;
Equipped with
the control unit acquires first information corresponding to an amount of use of the developing unit after the notification related to the replacement promotion by the notification device, and causes the notification device to issue a warning related to protection of the latent image unit based on the acquired first information.
1. An image forming apparatus comprising: The image forming device according to claim 1, characterized in that the control unit acquires second information corresponding to the usage amount of the latent image unit, and causes the notification device to issue a warning related to protection of the latent image unit based on the first information and the second information. The control unit is
3. The image forming apparatus according to claim 1, wherein the timing for causing the notification device to issue a protection warning for the latent image unit is made earlier as the usage amount of the latent image unit increases. the timing at which the notification device issues a protection warning for the latent image unit is made earlier as the usage amount of the developing unit increases;
4. The image forming apparatus according to claim 1, wherein the image forming apparatus further comprises a first fixing unit. a first image forming unit and a second image forming unit each including the latent image unit and the developing unit;
The image forming apparatus according to any one of claims 1 to 4, characterized in that the control unit acquires first information corresponding to the usage amount of the developing unit in the first and second image forming units, and causes the notification device to issue a protection warning for the latent image unit based on the acquired first information. the developing unit has a first memory in which the first information is stored,
6. The image forming apparatus according to claim 1, wherein the control unit acquires the first information from the first memory. the latent image unit has a second memory in which the second information is stored;
7. The image forming apparatus according to claim 2, wherein the control unit acquires the second information from the second memory. The image forming device according to any one of claims 1 to 7, characterized in that the notification device is a display device included in the image forming device or a display device capable of communicating with the image forming device. An image forming apparatus according to any one of claims 1 to 8, characterized in that the developer carried by the developer carrier contains external additive particles. The image forming apparatus according to any one of claims 1 to 9, characterized in that the cleaning member is a blade member whose tip extends in the opposite direction to the direction of movement of the image carrier relative to the cleaning member and abuts against the surface of the image carrier. An image forming apparatus in which a latent image unit and a developing unit are detachably attached to a main body of the apparatus,
The latent image unit includes:
a rotatable image carrier on which an electrostatic latent image is formed;
a cleaning member that contacts the image carrier to remove developer from the surface of the image carrier;
The developing unit comprises:
a developer carrier for developing the electrostatic latent image formed on the image carrier with a developer image;
Furthermore, the image forming apparatus
An electrification means;
A control unit;
a notification device that notifies the user of a promotion for replacing the developing unit;
the control unit acquires first information corresponding to a usage amount of the developing unit, and causes the notification device to perform a notification related to promotion of replacement of the developing unit based on the acquired first information;
the control unit, after the notification regarding the replacement promotion is made, estimates a film thickness reduction amount on the surface of the image carrier for a predetermined amount of usage of the latent image unit for the same combination of the developing unit and the latent image unit to be greater than the film thickness reduction amount for the predetermined amount of usage before the notification regarding the replacement promotion is made;
The image forming apparatus according to claim 1, wherein the control unit sets a charging bias for the charging means based on the estimated amount of film thickness reduction. The image forming apparatus according to claim 11, characterized in that the amount of film thickness reduction for a given amount of use of the developing unit becomes greater as the amount of use of the developing unit increases. The image forming apparatus according to claim 11 or 12, characterized in that the amount of film thickness reduction for a given amount of usage of the developing unit becomes greater as the amount of usage of the latent image unit increases. An image forming apparatus according to any one of claims 11 to 13, characterized in that the image carrier has at least a conductive layer, a charge generating layer as a photosensitive layer, and a charge transport layer laminated in that order on a conductive support, and the film thickness of the image carrier is the distance from the surface of the conductive support to the surface of the charge generating layer.

Images