JP4320535B2 - Process cartridge and image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus or the like that employs an electrophotographic method, and more particularly to an image forming apparatus or the like that has a function of grasping the usage state of an image carrier.
[0002]
[Prior art]
In recent years, so-called full-color tandem machines have been proposed in image forming apparatuses such as printers, copiers, and facsimile machines for the purpose of forming color images at high speed and high image quality. As a typical tandem machine, four image forming units of yellow (Y), magenta (M), cyan (C), and black (K) are arranged in parallel with each other, and each of these image forming units. The toner images of yellow, magenta, cyan, and black that are sequentially formed in step 1 are temporarily transferred onto the intermediate transfer belt once in a multiple, and then transferred onto the transfer paper from the intermediate transfer belt. Examples include fixing a toner image formed on the transfer paper to form a full-color or black-and-white (monochrome) image.
[0003]
FIG. 10 is a diagram showing an example of such a tandem machine. The image forming apparatus shown in FIG. 10 includes four image forming units 300Y, 300M, 300C, and 300K that form toner images having different colors of yellow, magenta, cyan, and black, and these image forming units 300Y and 300M. , 300C, 300K are arranged in parallel at regular intervals along the horizontal direction. The image forming units 300Y, 300M, 300C, and 300K have substantially the same configuration except that the color of the toner image to be formed is different, and after the surface of the photosensitive drum 301 is uniformly charged by the charging device 302 The exposure device 303 exposes the surface of the photosensitive drum 301 to form an electrostatic latent image corresponding to the image information of each color. The electrostatic latent image formed on the surface of the photosensitive drum 301 is visualized by a developing device 304 of a corresponding color to become a toner image, and this toner image is transferred to an intermediate transfer belt by a charger 305 for primary transfer. Multiple images are sequentially transferred onto 306. The toner remaining on the surface of the photosensitive drum 301 is removed by the cleaning device 307 to prepare for the next image forming process.
[0004]
The intermediate transfer belt 306 is circulated and driven at a speed equal to the rotational speed of the photosensitive drum 301 by a plurality of rollers 308, 309, 310, 311, 312 including a driving roller. The yellow, magenta, cyan, and black toner images transferred in multiple onto the intermediate transfer belt 306 are intermediate at the secondary transfer position (the position of the roller 311) provided below the intermediate transfer belt 306. The secondary transfer roll 313 that is in contact with the surface of the transfer belt 306 is collectively transferred onto the transfer paper 314 that is fed at a predetermined timing to the secondary transfer position. Thereafter, the transfer sheet 314 is conveyed to a fixing device (not shown), and is subjected to fixing processing with heat and pressure by the fixing device, thereby forming a color or monochrome image.
[0005]
Here, in recent years, an organic photosensitive drum (OPC photosensitive drum) has been widely used as the photosensitive drum 301. This OPC photosensitive drum is known to have various influences on image forming process conditions when the CT layer on the surface is scraped with use and the film thickness on the surface advances. Accordingly, it has been studied to maintain high-quality image formation by applying correction according to the amount of use of the photosensitive drum. At this time, it is necessary to accurately predict the usage amount (mainly the remaining film thickness) of the photoconductor that is the basis of the correction.
[0006]
In order to detect the wear of the photosensitive drum and obtain a high-quality image, the conventional technology has a memory in the process cartridge body, and records the usage time of the photosensitive member under different charging conditions and transfer conditions one by one in the memory. There is a technique for improving the image quality by applying the coefficient changed by the history information as the history information (see, for example, Patent Document 1 and Patent Document 2).
[0007]
[Patent Document 1]
Japanese Patent No. 3285785 (page 6-7, FIG. 2)
[Patent Document 2]
JP 2002-91098 A (page 8-9, FIG. 5)
[0008]
[Problems to be solved by the invention]
However, in the techniques described in Patent Document 1 and Patent Document 2, only use of a monochrome image in a single color is considered, and use in a so-called tandem machine is not assumed. Actually, the image formation conditions differ greatly between black-and-white image formation and full-color image formation, and the life of the photoreceptor depends on whether it was used with a YMC engine or a black (K) engine. Is also very different. For example, the change in film thickness applied to the surface layer of the photoconductor is different between the black (K) engine used for both monochrome and color images and the YMC engine used exclusively for color images. Therefore, it is necessary to consider the difference in the situation in which these are used.
[0009]
Further, in order to introduce all the various conditions in Patent Document 1 and Patent Document 2 described above into the four process cartridges of tandem and correspond to each of these conditions, a great deal of control is required. Furthermore, for example, in each process cartridge constituting the tandem machine, when all process cartridges having different solid characteristics are not inserted into the apparatus at the same time, for example, only in one place, or for image forming units having different settings. When the process cartridges are used interchangeably, it is difficult to cope with only the techniques described in Patent Document 1 and Patent Document 2 described above.
[0010]
The present invention has been made in order to solve the technical problems as described above. The object of the present invention is to provide an image bearing member even when a process cartridge is mounted on an engine of a different image forming unit. It is to recognize the usage situation correctly.
Another object is to further improve the recognition accuracy of the life of the image carrier even when the process cartridge is mounted on an engine of a different image forming unit.
[0011]
[Means for Solving the Problems]
For this purpose, according to the present invention, the information specifying the engine of the image forming unit is placed in the usage history, so that the prediction accuracy related to the life of the image carrier can be improved even if the process cartridge is temporarily replaced. It is possible to increase. That is, the present invention is a process cartridge that is used by being mounted on any of a plurality of engines in an image forming apparatus and that executes an image forming process, and is mounted with an image carrier that carries an image during image formation. And memory for storing information for identifying the engine. Here, the memory can store information relating to the cumulative usage amount used by the image carrier, and the information relating to the cumulative usage amount is stored in a temporary calculation amount calculated according to the mounted engine. To be determined.
[0012]
The memory also includes a cumulative storage area for storing a cumulative amount of use of the image carrier and / or a cumulative number of rotations of the image carrier, a temporary calculation value of the amount of use of the image carrier, and / or the image carrier. And a temporary storage area for storing a temporarily calculated value of the rotation speed.
[0013]
On the other hand, the present invention is an image forming apparatus in which a process cartridge is attached to each of a plurality of image forming units for forming an image, and images formed by an image carrier provided in the process cartridge can be transferred onto each other. The accumulated value storage means for storing the usage status of the image carrier for each process cartridge as a cumulative value, and the usage status of the image carrier stored as a cumulative value in the cumulative value storage means as a temporary calculation value Temporary calculation value storage means for storing, engine specifying information storage means for storing information for specifying the position of the image forming unit in which the process cartridge has been mounted in the past, and the image forming unit in which the process cartridge is currently mounted The position obtained from the information stored by the position recognition means for recognizing the position of the engine and the engine specific information storage means If the recognition position by the position recognizing means does not coincide, and a clear means for clearing the temporary calculated value stored in the temporary calculated value storage means.
[0014]
From another point of view, the image forming apparatus to which the present invention is applied includes a specific information storage unit that stores information for specifying an image forming unit in which the process cartridge is used for each process cartridge, and the specific information storage. Based on the information stored in the means, a recognition means for recognizing that the process cartridge has been mounted in another image forming unit, and the life of the image carrier based on the recognition by the recognition means. Generating means for generating generated information.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a diagram showing the overall configuration of an image forming apparatus to which this embodiment is applied, and shows a so-called tandem type digital color printer. An image forming apparatus shown in FIG. 1 includes an image processing system 10 that forms an image corresponding to gradation data of each color, a sheet conveyance system 40 that conveys recording paper (sheet), such as a personal computer or an image reader. An IPS (Image Processing System) 50, which is an image processing system that is connected to a device or the like and performs predetermined image processing on received image data, is provided.
[0016]
The image processing system 10 forms four images of yellow (Y), magenta (M), cyan (C), and black (K), which are a plurality of engines arranged in parallel at regular intervals in the horizontal direction. Units 11Y, 11M, 11C, and 11K, a transfer unit 20 that multiplex-transfers toner images of respective colors formed on the photosensitive drums 12 of the image forming units 11Y, 11M, 11C, and 11K onto the intermediate transfer belt 21, and an image forming unit ROS (Raster Output Scanner) 30 which is an optical system unit for irradiating laser beams to 11Y, 11M, 11C, and 11K is provided. Further, the main body 1 is provided with a fixing device 29 for fixing the image on the recording paper (sheet) secondarily transferred by the transfer unit 20 to the recording paper using heat and pressure. Further, toner cartridges 19Y, 19M, 19C, and 19K are provided for supplying toner of each color to the image forming units 11Y, 11M, 11C, and 11K.
[0017]
The transfer unit 20 includes a drive roll 22 that drives an intermediate transfer belt 21 that is an intermediate transfer member, a tension roll 23 that applies a constant tension to the intermediate transfer belt 21, and a secondary transfer of the superimposed toner images of each color onto a recording sheet. For this purpose, a backup roll 24 and a cleaning device 25 for removing residual toner and the like existing on the intermediate transfer belt 21 are provided. The intermediate transfer belt 21 is wound around the drive roll 22, the tension roll 23, and the backup roll 24 with a constant tension, and is rotated by a dedicated drive motor (not shown) having excellent constant speed. The drive roll 22 is circulated at a predetermined speed in the direction of the arrow. As the intermediate transfer belt 21, for example, a belt whose resistance is adjusted with a belt material (rubber or resin) that does not cause charge-up is used. The cleaning device 25 includes a cleaning brush 25a and a cleaning blade 25b, and removes residual toner, paper dust, and the like from the surface of the intermediate transfer belt 21 after the toner image transfer process is completed, and performs the next image forming process. It is comprised so that it may prepare for.
[0018]
In addition to a semiconductor laser and a modulator (not shown), the ROS 30 includes a polygon mirror 31 that deflects and scans laser light (LB-Y, LB-M, LB-C, and LB-K) emitted from the semiconductor laser. In the example shown in FIG. 1, since the ROS 30 is provided below the image forming units 11Y, 11M, 11C, and 11K, there is a risk of contamination due to dropping of toner or the like. Therefore, the ROS 30 is provided with a rectangular parallelepiped frame 32 for sealing each component member, and a glass window 33 through which the laser light (LB-Y, LB-M, LB-C, LB-K) passes is provided. It is provided above the frame 32 so as to enhance the shielding effect together with the scanning exposure.
[0019]
The sheet conveying system 40 is loaded with a recording paper (sheet) on which an image is recorded and fed, a nudger roll 42 that picks up and feeds the recording paper from the paper feeding device 41, and is fed from the nudger roll 42. A feed roll 43 that separates and conveys the recording sheets that have been separated one by one and a conveyance path 44 that conveys the recording sheets separated one by one by the feed roll 43 toward the image transfer unit are provided. Also, a registration roll 45 that conveys the recording paper conveyed through the conveyance path 44 in time toward the secondary transfer position, and a backup roll 24 that is provided at the secondary transfer position and is in pressure contact with the recording paper. And a secondary transfer roll 46 for secondary transfer of the image. Further, a discharge roll 47 for discharging the recording paper on which the toner image is fixed by the fixing device 29 to the outside of the main body 1 and a discharge tray 48 for stacking the recording paper discharged by the discharge roll 47 are provided. In addition, a double-sided conveyance unit 49 is provided that enables double-sided recording by inverting the recording paper fixed by the fixing device 29.
[0020]
Next, the operation of the image processing apparatus shown in FIG. 1 will be described. A color material reflected light image of a document read by a document reading device (not shown) and color material image data formed by a personal computer (not shown) are, for example, R (red), G (green), and B (blue). Each 8-bit reflectance data is input to the IPS 50. In IPS 50, the input reflectance data is subjected to predetermined image processing such as various image editing such as shading correction, position shift correction, brightness / color space conversion, gamma correction, frame deletion, color editing, and moving editing. Is done. The image data that has been subjected to image processing is converted into color material gradation data of four colors of yellow (Y), magenta (M), cyan (C), and black (K), and is output to the ROS 30.
[0021]
In the ROS 30, laser light (LB-Y, LB-M, LB-C, LB-K) emitted from a semiconductor laser (not shown) is converted into f-θ in accordance with input color material gradation data. The light is emitted to the polygon mirror 31 through a lens (not shown). In the polygon mirror 31, the incident laser light is modulated in accordance with gradation data of each color, deflected and scanned, and image forming units 11Y, 11M, 11C, and 11K through an imaging lens and a plurality of mirrors (not shown). The photosensitive drum 12 is irradiated. On the photosensitive drums 12 of the image forming units 11Y, 11M, 11C, and 11K, the charged surface is subjected to scanning exposure to form an electrostatic latent image. The formed electrostatic latent image is developed as a toner image of each color of yellow (Y), magenta (M), cyan (C), and black (K) in each of the image forming units 11Y, 11M, 11C, and 11K. Is done.
[0022]
The toner images formed on the photosensitive drums 12 of the image forming units 11Y, 11M, 11C, and 11K are multiplex-transferred onto an intermediate transfer belt 21 that is an intermediate transfer member. At this time, the black image forming unit 11 </ b> K that forms a black toner image is provided on the most downstream side in the moving direction of the intermediate transfer belt 21, and the black toner image is finally transferred to the intermediate transfer belt 21. Is done.
[0023]
On the other hand, in the sheet conveyance system 40, the nudger roll 42 rotates in accordance with the timing of image formation, and recording paper of a predetermined size is supplied from the paper feeding device 41. The recording sheets separated one by one by the feed roll 43 are conveyed to the registration roll 45 through the conveyance path 44 and are temporarily stopped. Thereafter, the registration roll 45 rotates in accordance with the movement timing of the intermediate transfer belt 21 on which the toner image is formed, and the recording paper is conveyed to the secondary transfer position formed by the backup roll 24 and the secondary transfer roll 46. . On the recording sheet conveyed from the lower side to the upper side at the secondary transfer position, the toner images in which the four colors are multiplexed are sequentially transferred in the sub-scanning direction using a pressing force and a predetermined electric field. The recording paper on which the toner images of the respective colors are transferred is subjected to a fixing process by heat and pressure by the fixing device 29 and then discharged by a discharge roll 47 to a discharge tray 48 provided on the upper portion of the main body 1. Instead of being discharged as it is to the discharge tray 48, the conveyance direction can be switched by a switching gate (not shown), and the recording sheet fixed by the fixing device 29 can be reversed by the duplex conveyance unit 49. After the reversed recording sheet is conveyed to the registration roll 45, an image can be formed on both sides of the recording sheet by forming an image on the other unprinted side by the same flow as described above. Become.
[0024]
Next, the image forming units 11Y, 11M, 11C, and 11K in the image process system 10 will be described in detail.
FIG. 2 is a diagram for explaining the configuration of the image forming units 11Y, 11M, 11C, and 11K. Here, the yellow (Y) image forming unit 11Y and the magenta (M) image forming unit 11M are shown. Has been. The other image forming units 11C and 11K are configured in substantially the same manner.
[0025]
The image forming units 11Y, 11M, 11C, and 11K include a photosensitive drum 12 as an image carrier that carries a toner image, a charger 13 that charges the photosensitive drum 12 using a charging roll 13a that is a charging member, and a charger. A developing device that develops an electrostatic latent image charged on the photosensitive drum 12 by the developing roller 14a by the laser beam (LB-Y, LB-M, LB-C, LB-K) from the ROS 30. 14. A primary transfer roll 15 provided on the intermediate transfer belt 21 so as to be opposed to the photosensitive drum 12 with the intermediate transfer belt 21 interposed therebetween. The toner image developed on the photosensitive drum 12 is transferred onto the intermediate transfer belt 21, and the photosensitive drum after transfer. 12 includes a cleaning device 16 that removes residual toner remaining on the surface 12. As the photosensitive drum 12 in the present embodiment, an OPC (Organic Photo Conductor) photosensitive drum is used.
[0026]
Next, the cartridge will be described.
FIG. 3 is a diagram for explaining the process cartridge in the present embodiment. In the present embodiment, the photosensitive drum 12, the charger 13, and the cleaning device 16 of each of the image forming units 11Y, 11M, 11C, and 11K are integrated for each color to form a process cartridge 60. Only the process cartridge 60 can be removed from the main body 1 of the image forming apparatus, and only the process cartridge 60 can be attached to the main body 1 so that the user can replace it. These process cartridges 60 can be used by being replaced between the image forming units 11Y, 11M, 11C, and 11K.
[0027]
FIG. 4 is a perspective view of the process cartridge 60 as seen from another direction. Each process cartridge 60 is provided with a nonvolatile memory 61. In the nonvolatile memory 61, for example, the process cartridge 60 is mounted in predetermined image forming units 11Y, 11M, 11C, and 11K such as the number of rotations of the photosensitive drum 12, the high voltage application time, and the number of prints. Each cartridge usage history information is stored. Since each process cartridge 60 is equipped with a non-volatile memory 61, even if the process cartridge 60 is used in different image forming units, its own use history information is stored in the process cartridge 60. You can save yourself. As a result, for each process cartridge 60, for example, the correct lifetime of the photosensitive drum 12 can be determined.
[0028]
Next, drive control in the image forming apparatus will be described.
FIG. 5 is a diagram for explaining drive control of the image forming apparatus to which the exemplary embodiment is applied. Based on the image signal subjected to the image processing by the IPS 50, the CPU (not shown) of the control circuit 100 executes the processing according to the program stored in the ROM (not shown). The control circuit 100 includes, as a drive system, a secondary transfer roll 46, a fixing device 29, a sheet conveying system 40, a main motor 101 that drives the developing device 14 (14K) in the black image forming unit 11K, and the like, and an intermediate portion of the transfer unit 20. An intermediate transfer member driving motor 102 for driving the transfer belt 21 and the like, and a photosensitive member for driving the photosensitive drum 12 (12Y, 12M, 12K) in the color image forming units 11Y, 11M, 11C except for the black image forming unit 11K. Development in the driving motor 103, the black photosensitive member driving motor 104 that drives the photosensitive drum 12 (12K) in the black image forming unit 11K, and the color image forming units 11Y, 11M, and 11C other than the black image forming unit 11K. The developing device drive motor 105 that drives the device 14 (14Y, 14M, 14C) is controlled. The control circuit 100 also controls a clutch 111 that is connected to the main motor 101 and switches the drive of the sheet conveying system 40, and a clutch 112 that is connected to the main motor 101 and switches the developing device 14 (14K) in the black image forming unit 11K. is doing. The control circuit 100 controls the operation of these various motors and clutches, thereby timing the respective portions in the image forming apparatus, and enables the image formation on the recording paper by the above-described operation.
[0029]
FIG. 6 is a diagram for explaining control of the image forming apparatus excluding drive control. The control circuit 100 controls a high voltage power supply (HVPS) 120. The high voltage unit 120 applies a charging bias to the charger 13 (13Y, 13M, 13C, 13K), and A developing bias is applied to the developing device 14 (14Y, 14M, 14C, 14K). An environmental sensor 130 for detecting environmental conditions such as temperature and humidity of the image processing system 10 is provided in the main body 1 and in the vicinity of the image processing system 10. Furthermore, the control circuit 100 includes a clock on its own or outside, and can grasp the current time.
[0030]
Furthermore, the control circuit 100 is connected to a non-volatile memory 61 (61Y, 61M, 61C, 61K) mounted on the process cartridge 60 constituting each of the image forming units 11Y, 11M, 11C, 11K. The main body memory 140 provided in the main body 1 of the image forming apparatus is connected. In the nonvolatile memory 61 (61Y, 61M, 61C, 61K) mounted on the process cartridge 60, information (history information etc.) relating to past usage records in each process cartridge 60 is stored as described above. In the present embodiment, the memory area of the non-volatile memory 61 is divided into a memory area of accumulated values for storing accumulated values such as the photoreceptor usage amount and the photoreceptor rotation speed, and a photoreceptor usage amount and the photoreceptor rotation speed. It is characterized by having a temporary memory area for storing temporary calculation values.
[0031]
The main body memory 140 also includes information such as the number of prints of recording paper counted by a PV (Page Volume) counter and the number of rotations of the photosensitive drum 12 counted by a cycle counter, as well as the power supply of the main body 1 in the image forming apparatus. Stores information (usage information) related to use from when the power is turned on from OFF or when the power saving mode is restored. In the control circuit 100, the high-voltage unit 120 and the like are controlled based on various information obtained from the nonvolatile memory 61 (61Y, 61M, 61C, 61K) and the main body memory 140, and an instruction from the control circuit 100 is given. Based on this, the history information of the nonvolatile memory 61 (61Y, 61M, 61C, 61K) is updated.
[0032]
The control circuit 100 controls the high voltage unit 120 and applies a charging bias to the charger 13 (13Y, 13M, 13C, 13K) by superimposing a DC voltage component and an AC voltage component including a vibration component (AC component). is doing. As the DC voltage, for example, −750 V is applied as constant voltage control. The AC voltage is a sine wave waveform, controlled at a process speed of 104 mm / sec (in full color mode), with a frequency f = 820 Hz, and an effective current value of 1.2 mA during constant current control. Is done. At this time, since the resistance value of the charger 13 (13Y, 13M, 13C, 13K) varies depending on the environment, the approximate voltage value is the peak-to-peak voltage Vpp = 1.8 kVpp in the normal environment (at room temperature), It becomes 2.2 kVpp at low temperature and low humidity (temperature 10 ° C., humidity 15%), and 1.6 kVpp at high temperature and high humidity (temperature 28 ° C., humidity 85%).
[0033]
Next, a method for determining the life of the photosensitive drum 12 will be described.
As the OPC photosensitive drum is used, the surface CT layer is gradually scraped. By changing the film thickness of the surface layer, the optimum value of the process formation condition changes every moment, for example, the surface potential of the photosensitive drum 12, the current necessary for primary transfer, and the like also change. Further, since the sensitivity curve of the photosensitive drum 12 changes, the light amount of the ROS 30 changes in order to obtain a desired density gradation. Here, the current film thickness T [μm] is, assuming that the initial film thickness is Tini [μm] and the photoreceptor usage amount Tused [μm]
T = Tini-Tused
It is represented by By increasing the prediction accuracy of the current film thickness T, the correction of process formation conditions is optimized, and a good image can be maintained.
[0034]
The initial film thickness Tini [μm] is usually a constant value, for example, 26 μm. However, for reasons such as extending the life of the process cartridge 60 and preventing image defects within a specified print volume, For example, a thick coating such as 32 μm may be applied. Information on the process cartridge 60 is first stored in a certain area of the nonvolatile memory 61 (61Y, 61M, 61C, 61K) at the time of shipment from the factory. This is read by the control circuit 100 of the main body 1 so that any engine (image forming units 11Y, 11M, 11C, 11K) suddenly has a process cartridge 60 with a different initial film thickness inserted therein. An accurate initial film thickness Tini can be known.
[0035]
Next, the photosensitive body usage amount Tused is mainly proportional to the rotational speed C [KCycle] of the photosensitive body. Therefore, using a predetermined coefficient A [μm / KCycle] for the rotational speed C,
Tused = C x A
It is obtained by. There are two actual calculations: a batch calculation method and a sequential difference accumulation method.
[0036]
First, in the batch calculation method, the photoreceptor usage amount Tused is calculated by the following procedure, and the calculated value is stored in the nonvolatile memory 61 (61Y, 61M, 61C, 61K) of the process cartridge 60.
(1) The photoconductor usage amount Tused (j) and the rotation speed C (j) before image formation are read from the nonvolatile memory 61.
(2) Count the rotational speed ΔC during image formation.
(3) At the end of image formation, C (j + 1) = ΔC + C (j) is obtained and stored in the nonvolatile memory 61.
(4) Tused (j + 1) = C (j + 1) × A is calculated and stored in the nonvolatile memory 61.
[0037]
On the other hand, in the successive difference accumulation method, a difference is multiplied by a coefficient to obtain a difference in usage amount, and the obtained difference is accumulated in the nonvolatile memory 61 (61Y, 61M, 61C, 61K) one by one. The procedure is as follows.
(1) The photoconductor usage amount Tused (j) and the rotation speed C (j) before image formation are read from the nonvolatile memory 61.
(2) Count the rotational speed ΔC during image formation.
(3) At the end of image formation, ΔTused = ΔC × A is calculated.
(4) The sum of the differences, that is,
C (j + 1) = ΔC + C (j)
Tused (j + 1) = ΔTused + Tused (j)
Are stored in the nonvolatile memory 61, respectively. However, this method increases the quantization error and leaves a problem of lack of accuracy. For example, in order to print one image, ΔC = 10 [Cycle] at most, and the lifetime of the photosensitive drum 12 of about C (j) = 300 K [Cycle] (300,000 cycles) is directly calculated. Compared to, the value is very small. In addition, since the value is too small, it may not be possible to count up without securing an appropriate amount of memory. Even with simple calculations, it is necessary to secure about 10K times (10,000 times) memory.
[0038]
Here, it is known that the coefficient A [μm / kCycle] varies depending on the charging condition and the process speed. For example, when considering AC charging, DC charging only, and idling (Bias = OFF) in three conditions, the coefficient A slightly changes at multiple process speeds. If the number of speeds is 3, 3 conditions × number of process speeds (3) = 9 types. For example, the charging frequency and the AC current value can be set so that the coefficient A does not change greatly at any process speed. The electrostatic energy for raising the photoreceptor surface potential should not change when the process speed changes, and keeping this constant is the filming (mainly caused by image defects due to poor charging and abnormal discharge due to excessive charging). This is also desirable from the viewpoint of preventing the phenomenon that the dischargeable substance is fixed on the surface of the photoreceptor due to excessive discharge. Further, by providing necessary and sufficient energy in accordance with the process speed, the energy for scraping the surface of the photoreceptor, which occurs as a side effect thereof, can be kept almost constant, so this coefficient A is considered not to change significantly.
[0039]
When the coefficient A at the process speed is set to be substantially the same, and the three types that consider only the charging conditions are considered, the usage amount Tused (j + 1) of the photosensitive member is
Tused (j + 1) = Tused_AC (j + 1) + Tused_DC (j + 1) + Tused_OFF (j + 1)
It can be disassembled and considered. Then, the number of rotations for each bias application condition is counted, the coefficients corresponding to the counts are sequentially multiplied, and individual values obtained by decomposition are calculated.
Tused_AC (j + 1) = C_AC (j + 1) × A_AC (j + 1),
Tused_DC (j + 1) = C_DC (j + 1) × A_DC (j + 1),
Tused_OFF (j + 1) = C_OFF (j + 1) x A_OFF (j + 1)
It becomes. Therefore, when written in a simplified manner, the photoreceptor usage Tused (j + 1) is
Tused (j + 1) = Σ [Cp (j + 1) x Ap (j + 1)] (p: = AC, DC, OFF)
It becomes.
[0040]
Also, this coefficient tends to increase as the amount of photoreceptor used increases. Therefore, instead of a simple linear expression, an approximation method using a quadratic expression such as C2 × A1 + C × A2 can be employed. However, depending on the characteristics of the photoreceptor and the setting of the life (period until the end of the life), it is often sufficient not to use the secondary equation. Further, using a quadratic expression may be disadvantageous in that the number of operation digits increases. Therefore, it is possible to consider a method in which the coefficient is changed for each section and is kept in a linear expression. In such a case, (p: = AC, DC, OFF) and n ≧ 1,
Section 1 [0 <Tused (j) <k1]; Tused (j + 1) = Σ [Cp (j + 1) × Ap [1] (j + 1)]
Section 2 [k1 <Tused (j) <k2]; Tused (j + 1) = Σ [Cp (j + 1) × Ap [2] (j + 1)]
...
Section n [k (n-1) <Tused (j) <k (n)]; Tused (j + 1) = Σ [Cp (j + 1) × Ap [n] (j + 1)]
And can be expressed in table format. Thereby, it is possible to predict the usage amount of the photoconductor with high accuracy. Even if the engine position is different from Y, M, C, and K, each engine may be calculated using the same formula as long as the process formation conditions are the same.
[0041]
On the other hand, there are cases where it is desired to change the process formation conditions for each engine. For example, at the time of AC superimposed charging that greatly contributes to wear, the current value setting value is increased only for the K engine that places more importance on black and white image quality, or the charging potential is slightly decreased only for the C engine, for example, considering the overall color balance. It is assumed that If the setting of the charger 13 is changed, the discharge state changes and the wear rate changes. The K engine is always used in contact with the intermediate transfer belt 21 even when no electric discharge is performed, while the Y, M, and C engines are used without being in contact with the intermediate transfer belt 21 during monochrome printing. Sometimes you want to reduce mechanical damage as much as possible. In these cases, it is necessary to change the coefficient in each engine. If we expand the formula assuming that all the coefficients are different,
Section n [k (n-1) <Tused (j) <k (n)]; (n ≧ 1)
Tused_ # Y (j + 1) = Σ [Cp (j + 1) × Ap [n] (j + 1)] (p: = AC_ # Y, DC_ # Y, OFF_ # Y)
Tused_ # M (j + 1) = Σ [Cp (j + 1) × Ap [n] (j + 1)] (p: = AC_ # M, DC_ # M, OFF_ # M)
Tused_ # C (j + 1) = Σ [Cp (j + 1) × Ap [n] (j + 1)] (p: = AC_ # C, DC_ # C, OFF_ # C)
Tused_ # K (j + 1) = Σ [Cp (j + 1) × Ap [n] (j + 1)] (p: = AC_ # K, DC_ # K, OFF_ # K)
It becomes. That is, each engine measures the number of rotations according to the charging conditions and selects an appropriate coefficient according to the amount of use of each photosensitive drum 12 (12Y, 12M, 12C, 12K). Photoconductor usage can be calculated accurately.
[0042]
However, changing the coefficient for each engine involves some danger. That is, the Cp that is the basis of the calculation, that is, the numbers C (AC), C (DC), and C (OFF) is certainly the amount that the process cartridge 60 has rotated, but it is really the engine (image). Whether it has been used in one of the forming units 11Y, 11M, 11C, 11K) remains unclear. When the developing device 14 and the toner cartridges 19Y, 19M, 19C, and 19K are not integrated as in the process cartridge 60 in the present embodiment, the Y, M, C, and K are not particularly distinguished anywhere. There is no problem even if attached. Therefore, even if the process cartridge 60 has not yet reached the end of its life, it does not always stay in the same engine and can be freely inserted and removed. When such a process cartridge 60 is used, for example, although C (AC_ # Y) is calculated, C (AC_ # K) may actually be used. In such a case, it is necessary to use A (AC_ # K) instead of A (AC_ # Y) as a coefficient, and the prediction and the actual result are greatly out of order. The larger the difference in coefficients between engines, the greater these errors. In the present embodiment, the correct calculation can be executed by using which engine the process cartridge 60 is used, that is, information on the position where each photosensitive drum 12 is placed.
[0043]
FIG. 7 is a flowchart showing a method for determining the life of the photosensitive drum 12 in the present embodiment using the sequential difference accumulation method. In the control circuit 100, first, the photoreceptor usage Tused (j) and the rotation speed C (j) before image formation are read from the nonvolatile memory 61 (step 201). Further, the current engine position #L (= Y, M, C, K) from which information such as the photoconductor usage amount Tused (j) and the rotational speed C (j) is read is checked (step 202). Next, the rotational speed ΔC of the photosensitive drum 12 during image formation in the image process system 10 of the main body 1 is counted (step 203). After that, at the end of image formation, the coefficient A_ # L corresponding to the current engine position is selected,
ΔTused = ΔC × A_ # L
Is calculated (step 204). And the sum of the differences, i.e.,
C (j + 1) = ΔC + C (j), Tused (j + 1) = ΔTused + Tused (j)
Are stored in the non-volatile memory 61 (61Y, 61M, 61C, 61K) (step 205), and the process ends. In the successive difference accumulation method shown in FIG. 7, information about the past engine position is not necessary because a coefficient is selected for each print in accordance with the current engine position.
[0044]
FIG. 8 is a flowchart showing a method for determining the life of the photosensitive drum 12 in the present embodiment using the batch calculation method. First, as a premise of processing, it is necessary that the rotational speed at each engine is stored in the nonvolatile memory 61 (61Y, 61M, 61C, 61K). At this time,
C (i) = Cy (i) + Cm (i) + Cc (i) + Ck (i)
And disassemble. Actually, as mentioned above, it decomposes even under each charging condition.
Cy (i) = Cy_AC (i) + Cy_DC (i) + Cy_OFF (i)
Cm (i) = Cm_AC (i) + Cm_DC (i) + Cm_OFF (i)
Cc (i) = Cc_AC (i) + Cc_DC (i) + Cc_OFF (i)
Ck (i) = Ck_AC (i) + Ck_DC (i) + Ck_OFF (i)
Therefore, for each engine, it is necessary to store the 16 rotational speeds expressed by the above formula in the nonvolatile memory 61 (61Y, 61M, 61C, 61K). Thereafter, the calculation is executed according to the flow shown in FIG.
[0045]
First, as shown in FIG. 8, in the control circuit 100, the photoreceptor usage Tused (j) before image formation and the rotation speeds Cy (i), Cm (i), Cc (i), Ck (i) Is read from the nonvolatile memory 61 (61Y, 61M, 61C, 61K) (step 211). Further, the current engine position #L (= Y, M, C, K) is checked (step 212). Thereafter, the rotational speed ΔC of the photosensitive drum 12 during image formation in the image process system 10 is counted (step 213). This rotational speed ΔC is
When # L = Y, ΔCy = ΔC, ΔCm = ΔCc = ΔCk = 0
When # L = M, ΔCm = ΔC, ΔCy = ΔCc = ΔCk = 0
When # L = C, ΔCc = ΔC, ΔCy = ΔCm = ΔCk = 0
When # L = K, ΔCk = ΔC, ΔCy = ΔCm = ΔCc = 0
It becomes.
[0046]
Thereafter, at the end of image formation, the rotational speed at the current engine position is obtained and stored in the nonvolatile memory 61 (61Y, 61M, 61C, 61K) (step 214). The stored rotation speed is
Cy (j + 1) = ΔCy + Cy (j)
Cm (j + 1) = ΔCm + Cm (j)
Cc (j + 1) = ΔCc + Cc (j)
Ck (j + 1) = ΔCk + Ck (j)
It is. Then, Tused (j + 1) is calculated by the following formula and stored in the non-volatile memory 61 (61Y, 61M, 61C, 61K) (step 215), and the process ends.
Tused (j + 1) = Cy (j + 1) x A_ # Y + Cm (j + 1) x A_ # M
+ Cc (j + 1) x A_ # C + Ck (j + 1) x A_ # K
In this way, all the information on how much the process cartridge 60 is used by which engine is stored in the nonvolatile memory 61 (61Y, 61M, 61C, 61K), and the process cartridge 60 is different by multiplying each coefficient. Problems when used between engines can be prevented. However, the method shown in FIG. 8 requires a lot of memory, and it is necessary to secure a memory area that is four times the normal because of the fact that it is rarely used in normal usage, and there remains a problem from the viewpoint of memory usage efficiency.
[0047]
Therefore, in the present embodiment, in addition to the methods shown in FIGS. 7 and 8, as a most preferable aspect, information on the final use engine position (the engine to which the process cartridge 60 is attached is stored in the nonvolatile memory 61 of the process cartridge 60). When the process cartridge 60 is mounted at a predetermined engine position, the stored engine position is compared with the current engine position, and if it is different, the temporary calculated value memory is stored. It is characterized by resetting and newly calculating.
[0048]
As information indicating the position of the final use engine, an appropriate integer is written in the nonvolatile memory 61 of the process cartridge 60. For example, 1 if the currently installed engine is in the Y position, 2 for the M position, 3 for the C position, and 4 for the K position. Such information is updated at an appropriate timing from when the process cartridge 60 is mounted to when printing is completed. At this time, in the present embodiment, as described above, the current temporary calculation area is newly provided in addition to the cumulative calculation area with respect to the usage amount of the photosensitive body and the rotational speed of the photosensitive body. That is, a temporary calculation area for storing the temporary photoconductor usage amount Tused_tmp and the temporary photoconductor rotation speed C_tmp is provided. The temporary photosensitive member rotation number C_tmp can be replaced with the conventional rotation number C in order to save memory. In the case of substituting the conventional rotational speed C, information on the cumulative rotational speed may be lost when the process cartridge 60 is collected and the market information is analyzed, but this does not affect the operation of the machine.
[0049]
FIG. 9 is a flowchart showing a method of determining the life of the photosensitive drum 12 as the most preferable aspect in the present embodiment. The control circuit 100 firstly uses the photosensitive body usage Tused (j), Tused_tmp (j), rotation speed C (j), C_tmp (j) before image formation from the nonvolatile memory 61 (61Y, 61M, 61C, 61K). Is read (step 221). Then, in the image forming units 11Y, 11M, 11C, and 11K, the current engine position #L (= Y, M, C, K) is checked (step 222), and the final use engine position #L_OLD (= Y, M, C, K) are checked from the nonvolatile memory 61 (step 223).
[0050]
  Here, the control circuit 100 determines whether or not the current engine position matches the final use engine position (step 224). If they match (# L = _L_OLD), the number of rotations ΔC during image formation is counted (step 225).
    C_tmp (j + 1) = ΔC + C_tmp (j)
And the result is stored in the nonvolatile memory 61 (step 226). After that, the coefficient A_ # L corresponding to the current engine position is selected at the end of image formation,
    Tused_tmp (j + 1) = C_tmp (j + 1) x A_ # L
Is calculated (step 227). In the control circuit 100, the temporary calculation amount is added to the cumulative amount,
    Tused (j + 1) = Tused (j) + Tused_tmp (j + 1)
    C (j + 1) = C (j) +ΔC
Are stored in the nonvolatile memory 61 (step 228), and the process ends.
[0051]
In step 224, if the current engine position and the final use engine position do not match (does not match) (# L ≠ _L_OLD), first, the temporary photoconductor usage amount and the temporary photoconductor rotation obtained from the nonvolatile memory 61 are used. The number is cleared (step 230). That is,
Tused_tmp (j) = 0, C_tmp (j) = 0
Note that, when looking at an arithmetic expression described later, it can be understood that even if this process is omitted, it is automatically replaced, but here, the steps are clearly shown for easy understanding.
[0052]
  After this processing, the control circuit 100 counts the rotation speed ΔC during image formation (step 231), and at the end of image formation
    C_tmp (j + 1) = ΔC (+ C_tmp (j))
                 = ΔC
Is calculated and the result is stored in the nonvolatile memory 61 (step 232). In addition, the coefficient A_ # L corresponding to the current engine position is selected at the end of image formation,
    Tused_tmp (j + 1) = C_tmp (j + 1) x A_ # L
Is calculated (step 233). Then, as shown in the following equation, each temporary calculation amount is added to the accumulated amount.
    Tused (j + 1) = Tused (j) + Tused_tmp (j + 1)
    C (j + 1) = C (j) +ΔC
As described above, when the current position and the final use position are different, the temporary calculation area is reset and the rotation speed is newly calculated. The past accumulated usage is secured in another area, and the added new accumulated usage is stored in the non-volatile memory 61 (step 234), accurate information is stored, and the process ends.
[0053]
In this manner, various information used for calculating the life of the photosensitive drum 12 is stored in the nonvolatile memory 61 of the process cartridge 60. In adopting this method, information for temporary calculation is newly defined as information to be stored in the nonvolatile memory 61. As essential,
Tused: Cumulative photoconductor usage
C_tmp: Temporary calculation speed
#L_OLD: Last used engine position
There is. For example, #L_OLD is a single-digit integer, so 1Byte is enough. Further, Tused_tmp does not necessarily need to be stored in the nonvolatile memory 61, and the main body memory 140 (main body side non-volatile memory) having a relatively large capacity even when considering backup such as when the power is cut off during the calculation. It is enough to store it in Furthermore, the accumulated photosensitive member rotation speed C is often useful for analyzing market information, for example, and for this purpose, it is desirable to store it in the nonvolatile memory 61. However, it is not always necessary if the number of rotations of the photosensitive drum 12 and the number of prints are separately stored in a format adapted to the application of market information analysis.
[0054]
The method shown in FIG. 9 is a method that uses the sequential difference calculation method shown in FIG. 7 only when the process cartridge 60 moves to another engine. Therefore, in the case of an extreme usage method in which the position of the process cartridge 60 changes for each print, it may be considered that it is the same as the sequential difference calculation method shown in FIG. On the other hand, if the position of the process cartridge 60 does not change even once it is mounted, it is the same as the collective calculation method shown in FIG. 8, and the calculation accuracy can be kept high. According to the present embodiment, Tused can be accurately calculated by the method described above. Therefore, the current photoconductor usage T can be predicted from T = Tini−Tused described above. Therefore, it is possible to perform appropriate correction when further performing correction of the surface potential of the photoconductor, correction of the primary transfer current, correction of the ROS light amount, and the like using the photoconductor usage amount T.
[0055]
Note that the nonvolatile memory 61 of the process cartridge 60 that stores information that leads to changing the image forming conditions on the main body 1 side needs to pay close attention to data alteration / damage / missing information. is there. As countermeasures, for example,
(1) A method of erasing the memory contents when a specific area of the nonvolatile memory 61 is accessed,
(2) A method of performing communication between the nonvolatile memory 61 and the control circuit 100 on the main body 1 side by encrypted wireless communication,
(3) A method of performing communication between the main body 1 side and the nonvolatile memory 61 when the drive system motor (main motor 101 or the like) serving as a noise source is stopped or the output is reduced can be considered. With the method (1), it is possible to prevent the non-volatile memory 61 from being tampered with. The control circuit 100 of the main body 1 accesses other information while avoiding the location of this specific area, but becomes a barrier when a third party who does not know it tries to decipher it. Further, the method (2) makes the purpose of (1) more reliable. Since the terminals of the conventional wired type chip are exposed, it is relatively easy to communicate with the non-volatile memory 61 which is the inside chip. However, if the wireless type is used, it is necessary to prepare a dedicated antenna and communication protocol. Information is not reachable. Furthermore, the method (3) can be applied to both cases (1) and (2). When there is a particularly large output stepping motor in the drive system, communication with a memory which is serial communication is likely to be hindered by a pulse signal generated by the stepping motor. Since it is not necessary to always access the nonvolatile memory 61, good results can be obtained by communicating with the timing when the drive system motor is stopped or the output is down.
[0056]
As described above in detail, according to the present embodiment, individual characteristics of the process cartridge 60 can be obtained in a simple and inexpensive manner without consuming a large amount of the memory (nonvolatile memory 61) of the process cartridge 60. Accordingly, it is possible to change the optimum life prediction and image formation setting accordingly. Further, by putting engine information (information indicating which image forming units 11Y, 11M, 11C, and 11K are used) in the usage history, even if the process cartridge 60 is temporarily replaced, the prediction accuracy is impaired. In addition, individual image forming conditions can be set for each engine. That is, it is possible to reliably perform the correction operation for the item affected by the usage amount of the photosensitive member under various process formation conditions.
[0057]
Further, when a mechanism for prompting the replacement of the process cartridge 60 due to the reduction of the film thickness of the photosensitive drum 12 is adopted, the prediction accuracy of the film reduction can be greatly improved, and the process cartridge 60 can be used to the end of its lifetime. Can be used. Furthermore, according to the present embodiment, since the machine automatically operates according to the individual information of the process cartridge 60, it is not necessary to change the setting on the main body side according to the type of the process cartridge 60. . Further, by making it difficult to access the nonvolatile memory 61, it is possible to prevent tampering / damage / missing of data in the storage means. As a result, it is possible to prevent the image from being disturbed by predictive control based on incorrect information, or the main body 1 or the process cartridge 60 from being damaged.
[0058]
【The invention's effect】
Thus, according to the present invention, it is possible to accurately predict the lifetime of the image carrier constituting the process cartridge.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an overall configuration of an image forming apparatus to which the exemplary embodiment is applied.
FIG. 2 is a diagram for explaining a configuration of an image forming unit.
FIG. 3 is a diagram for explaining a process cartridge according to the present embodiment.
FIG. 4 is a perspective view of a process cartridge as viewed from another direction.
FIG. 5 is a diagram for describing drive control of an image forming apparatus to which the exemplary embodiment is applied.
FIG. 6 is a diagram for explaining control of the image forming apparatus excluding drive control.
FIG. 7 is a flowchart showing a method for determining the life of a photosensitive drum in the present embodiment using a successive difference accumulation method.
FIG. 8 is a flowchart showing a method for determining the life of a photosensitive drum in the present embodiment using a batch calculation method.
FIG. 9 is a flowchart showing a method for determining the life of a photosensitive drum as the most preferable aspect in the present embodiment.
FIG. 10 is a diagram showing an example of a tandem machine as a conventional technique.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Main body, 10 ... Image process system, 11Y, 11M, 11C, 11K ... Image forming unit, 12 ... Photosensitive drum, 13 ... Charger, 13a ... Charging roll, 13b ... Shaft, 14 ... Developer, 15 ... Primary Transfer roller, 16 ... cleaning device, 20 ... transfer unit, 21 ... intermediate transfer belt, 40 ... sheet conveying system, 50 ... IPS (Image Processing System), 51 ... housing, 56 ... coil spring, 60 ... process cartridge, 61 ... Nonvolatile memory, 100 ... control circuit, 120 ... high voltage unit, 140 ... main body memory

Claims (5)

A process cartridge that is used by being mounted on any of a plurality of engines in an image forming apparatus and that executes an image forming process,
An image carrier for carrying an image during image formation;
After being mounted on any engine, the image determined based on information for identifying the engine of the image carrier used for image formation and a temporary calculation amount calculated according to the mounted engine A memory for storing information on the usage of the carrier;
Including
The temporary calculation amount is obtained by multiplying a coefficient selected in accordance with the engine .   The memory includes a cumulative storage area for storing a cumulative usage amount of the image carrier and / or a cumulative rotation speed of the image carrier, a temporary calculation value of the usage amount of the image carrier, and / or the image carrier. 2. The process cartridge according to claim 1, further comprising a temporary storage area for storing a temporary calculation value of the rotational speed of the body. An image forming apparatus in which a process cartridge is mounted on each of a plurality of image forming units for forming an image, and images formed by an image carrier provided in the process cartridge can be overlaid and transferred.
Cumulative value storage means for storing the usage status of the image carrier as a cumulative value for each process cartridge;
Temporary calculation value storage means for multiplying a use condition of the image carrier after being stored as the cumulative value in the cumulative value storage means by a coefficient selected according to the image forming unit and storing it as a temporary calculation value; ,
Only including,
The cumulative value storage means adds the temporary calculation value stored in the temporary calculation value storage means to the cumulative value and stores it as a new cumulative value . Engine specifying information storage means for storing information for specifying the position of the image forming unit in which the process cartridge has been mounted in the past;
Position recognition means for recognizing the position of the image forming unit to which the process cartridge is currently mounted;
When the position obtained from the information stored by the engine specific information storage means and the position recognized by the position recognition means do not match, the temporary calculation value stored in the temporary calculation value storage means is cleared. The image forming apparatus according to claim 3 , further comprising a clearing unit. An image forming apparatus in which a process cartridge is mounted on each of a plurality of image forming units for forming an image, and images formed by an image carrier provided in the process cartridge can be overlaid and transferred.
Specific information storage means for storing information for specifying the image forming unit in which the process cartridge is used for each process cartridge;
Recognizing means for recognizing that the process cartridge is mounted on another image forming unit based on the information stored in the specific information storing means;
A coefficient corresponding to the current position of the image forming unit is selected based on recognition by the recognition means, and a temporary calculation amount obtained by multiplying the selected coefficient is added to generate the cumulative usage amount of the process cartridge. An image forming apparatus including a generating unit.

Images