JPH1039723A - Process cartridge and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process cartridge and image forming device which reduces the number of detection images required for the control of image forming conditions, controls the image forming conditions with less time and toner consumption without selecting an electrophotographic photoreceptor, and obtains a high quality image free of density change. SOLUTION: The process cartridge 100 integrates a photoreceptive drum 1, charge roller 2, and cleaning means 7 all of which are its constituent parts, and is free to be attached/detached to/from the main body 90 of the image forming device via an attaching guide means 80. The cartridge 100 is further equipped with a nonvolatile storage means 10 for storing information on the sensitivity of the photoreceptive drum 1. When the detection image is formed on the photoreceptive drum 1, its density is measured by a sensor 20, and the image forming conditions are controlled based on it, the information on the photoreceptive drum sensitivity is read from the storage means 10 by means of a CPU 11, to use it for the control of the image forming conditions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a process cartridge and an image forming apparatus.

[0002] In the present invention, as an image forming apparatus,
For example, an electrophotographic copying machine, an electrophotographic printer (for example, an LED printer, a laser beam printer, and the like), an electrophotographic facsimile, an electrophotographic word processor, and the like are included.

A process cartridge is a device in which a charging unit, a developing unit or a cleaning unit and an electrophotographic photosensitive member are integrally formed into a cartridge, and this cartridge is detachable from an image forming apparatus main body.
Alternatively, at least one of the charging unit, the developing unit, and the cleaning unit and the electrophotographic photosensitive member are integrally formed into a cartridge so as to be detachable from the image forming apparatus main body. Into a cartridge so that it can be attached to and detached from the image forming apparatus main body.

[0004]

2. Description of the Related Art Conventionally, in an image forming apparatus using an electrophotographic image forming process, an electrophotographic photosensitive member and process means acting on the electrophotographic photosensitive member are integrally formed into a cartridge, and the cartridge is used as a main body of the image forming apparatus. A process cartridge system which can be attached to and detached from is used. According to this process cartridge system, the maintenance of the apparatus can be performed by the user himself without relying on a service person, so that the operability can be remarkably improved. Therefore, this process cartridge system is widely used in electrophotographic image forming apparatuses.

FIG. 14 is a sectional view showing an image forming apparatus in which a conventional process cartridge can be mounted.

As shown in FIG. 14, a process cartridge (photosensitive drum cartridge) 100 integrates a photosensitive drum 1, which is an electrophotographic photosensitive member, a charging roller 2, which is a charging means, and a cleaning means 7, and is integrally formed. 1
5, the image forming apparatus main body 90 is formed.
Is detachable via a mounting guide means 80.

The photosensitive drum 1 has an organic photoreceptor (OPC) or a-Si, Cd
It is constituted by applying a photoconductor made of S, Se, or the like, and is rotationally driven in a direction indicated by an arrow in FIG.
The surface of the photosensitive drum 1 is uniformly charged to a predetermined potential by the charging roller 2. An exposure device 3 is installed above the process cartridge 100. When a signal according to a yellow image pattern is input, the exposure device 3 irradiates the photosensitive drum 1 with a light image of the image pattern. An electrostatic latent image is formed on the surface of the substrate.

In the direction of rotation of the photosensitive drum 1, downstream of the process cartridge 100, four developing devices 4 (4
a, 4b, 4c, 4d) are mounted on the support 5 and installed. Each of the developing devices 4a to 4d is formed into a cartridge, and is detachable from the support 5 (accordingly, the apparatus main body 90). When the photosensitive drum 1 advances in the direction of the arrow, the support 5 rotates, and the developing unit 4 a containing the yellow (Y) toner of the four developing units 4 faces the photosensitive drum 1.
The latent image on the photosensitive drum 1 is developed by the developing device 4a selected in this way, and is visualized as a yellow toner image. The obtained yellow toner image is transferred onto an intermediate transfer belt 6 which is an intermediate transfer body.

The intermediate transfer belt 6 has three support rollers 6
1, 62, 63, and the process cartridge 1
The support roller 62 rotates in the direction of the arrow in FIG. The intermediate transfer belt 6 is made of a resin belt made of PVdF, PET, polycarbonate, or the like, or silicone rubber, urethane rubber, E
A rubber belt such as a PDM or a composite belt having a resin layer provided on the rubber belt is used. A transfer roller 64 serving as a primary transfer member is provided on a portion of the inner surface of the intermediate transfer belt 6 facing the photosensitive drum 1, and a predetermined bias is applied to the transfer roller 64 from a high-voltage power supply (not shown). Is transferred onto the intermediate transfer belt 6 (primary transfer).

The above steps are further carried out by adding a magenta color (M),
By performing the process for cyan (C) and black (K), a color image is formed on the intermediate transfer belt 6 by superimposing toner images of four colors of yellow, magenta, cyan, and black. The four color toner images are collectively transferred by a secondary transfer roller 65 onto a transfer material (such as paper) conveyed in synchronization with the movement of the intermediate transfer belt 6 (secondary transfer). The transfer material onto which the four color toner images have been transferred is conveyed to a conventionally known heating / pressure fixing device 8, where the toner images are fused and fixed to form a full-color image. The transfer residual toner remaining on the photosensitive drum 1 is cleaned by a known cleaning means 7 which is a blade.

In the above-described image forming apparatus, an image (detection image) for density detection is formed on the photosensitive drum 1 prior to normal image formation, and the density of the detection image is determined by a light emitting element and a light receiving element. Of the photosensitive drum 1 based on the density.
Various image forming conditions such as a light amount of the exposure device 3 and a developing bias applied to the developing device 4 are controlled.

A plurality of types of detected images are formed by changing the image forming conditions, and by detecting the densities of these, image forming conditions for obtaining a desired density are obtained.

The factors that change the density of an image are complicated,
The factors of the density change occurring before and after the replacement of each cartridge such as the process cartridge 100 and the developing units 4a to 4d which are the developing cartridges are mainly caused by variations in sensitivity in manufacturing the photosensitive drum 1 and frictional charging characteristics in manufacturing toner. And so on. As a factor of the density change in the use process, there is a characteristic change due to a use environment, a developing device, and the number of image formed on the photosensitive drum.

Efforts to stabilize these fluctuation characteristics are made every day, but they are still insufficient. Therefore, especially in a color image forming apparatus, in order for a user to obtain a desired density and color balance, image forming conditions for four colors of YMCK must be adjusted, and the above-described control is automated to automatically control the image density. It is useful to do. The above-described control may be performed when the power of the image forming main body is turned on, when each cartridge is exchanged, or every predetermined number of image formations. Further, when a temperature and humidity sensor for detecting the temperature and humidity inside the apparatus main body is provided. This may be performed when there is a predetermined change in temperature and humidity.

[0015]

However, in the above-mentioned conventional image forming apparatus, the image forming conditions must be controlled in consideration of all the fluctuation factors.
It is necessary to form a detection image in which many image forming conditions are changed, and accordingly, it takes a long time to perform control, and there is a problem that a large amount of toner is consumed.

Although it is conceivable to reduce the number of detected images, the control error increases accordingly, and the color balance deteriorates, especially in a color image, and the practicality becomes poor. Also, at the time of manufacture, the characteristics of the photosensitive drum and the toner may be selected to select those with little fluctuation.
The cost increases accordingly.

The present invention is a further development of the above prior art.

An object of the present invention is to reduce the number of detection images required for controlling image forming conditions, and to control image forming conditions with reduced time and toner consumption without selecting electrophotographic photosensitive members. Another object of the present invention is to provide a process cartridge and an image forming apparatus capable of obtaining a high-quality image without a change in density.

[0019]

The above object is achieved by a process cartridge and an image forming apparatus according to the present invention. In summary, the present invention relates to a process cartridge detachable from an image forming apparatus main body, wherein the process cartridge has an electrophotographic photosensitive member, and a process means acting on the electrophotographic photosensitive member. A storage unit that stores sensitivity information of the body, and when controlling the image forming conditions based on the density of the detection image formed on the electrophotographic photosensitive member, when the electrophotographic photosensitive member stored in the storage unit is controlled. A process cartridge in which sensitivity information is read and used for controlling the image forming conditions. According to the present invention, the storage unit can be a nonvolatile storage unit.

According to one aspect of the present invention, the number of image formations of the process cartridge is further stored in the storage means, and the number of image formations stored in the storage means is read in controlling the image formation conditions. Then, the sensitivity information of the electrophotographic photosensitive member used for controlling the image forming conditions is corrected based on the number of images formed.

According to another aspect of the present invention, there is provided an image forming apparatus in which a process cartridge is detachably mountable and which forms an image on a recording medium, wherein (a) an electrophotographic photosensitive member and the electrophotographic photosensitive member are acted on. Mounting means for detachably mounting a process cartridge having process means and further having storage means for storing sensitivity information of the electrophotographic photoreceptor to the image forming apparatus main body; and (b) transporting the recording medium And an image forming apparatus.

According to still another aspect of the present invention, there is provided an image forming apparatus having an electrophotographic photosensitive member and process means for acting on the electrophotographic photosensitive member, a storage means for storing sensitivity information of the electrophotographic photosensitive member. An image forming apparatus comprising:

[0023]

Embodiments of the present invention will be described below in more detail with reference to the drawings.

Embodiment 1 FIG. 1 is a sectional view showing an embodiment of an image forming apparatus to which a process cartridge according to the present invention can be mounted. This embodiment shows a laser beam printer. Hereinafter, embodiments of the present invention will be described with reference to the drawings. Members having the same configuration and operation as those of the conventional image forming apparatus shown in FIG. 14 are denoted by the same reference numerals, and description thereof will be omitted.

A process cartridge (photosensitive drum cartridge) 100 according to the present invention integrates a photosensitive drum 1, which is an electrophotographic photosensitive member, a charging roller 2, which is a charging means, and a cleaning means 7, and is a main body of an image forming apparatus. It is detachable with respect to 90 via the mounting guide means 80.

The feature of the present invention is that the process cartridge 1
00, a non-volatile storage means 10 is provided.
That is, the sensitivity of the photosensitive drum 1 is determined based on the information stored in “0”, and the image forming conditions used when controlling the image forming conditions can be changed.

Non-volatile storage means 10 used in the present invention
Is not particularly limited as long as it can store and hold signal information in a rewritable manner. For example, an electrical storage means such as a RAM and a rewritable ROM, and a magnetic storage medium such as a magnetic recording medium, a magnetic bubble memory, and a magneto-optical memory. For example, a dynamic storage means is used. In this embodiment, NVRAM (Non Volatile RAM) is used in terms of ease of handling and cost.

A CPU 11 is provided in the main body 90 of the image forming apparatus. As shown in FIG.
2 and the above NVRAM 10 are connected. CP
U11 is the NVRAM of the photosensitive drum cartridge 100
10 is read, and the read information is read from the ROM 12
It is processed according to the information in.

In this embodiment, the primary charge potential of the photosensitive drum 1 is -600 V, and the exposure light amount is set such that the potential of the exposed portion is -200 V at the central value of the sensitivity of the photosensitive drum. As the detection image, a pattern for printing 3 × 3 in a 4 × 4 dot matrix was used as shown in FIG. The image for detection was formed by changing the developing bias among the image forming conditions, and the developing bias at which the optical density became 1.0 was obtained, and the developing bias was controlled.

FIGS. 4 to 6 are graphs showing a change in the density of the detection image when the developing bias is changed. FIG. 4 shows a case where a photosensitive drum having central sensitivity and an exposure unit potential of −200 V is used, and FIG. 5 shows a photosensitive drum having an upper limit sensitivity and an exposure unit potential of −100 V. FIG. 6 shows that the sensitivity has the lower limit and the exposed portion potential is -30.
In the case where the photosensitive drum of 0 V is used, the photosensitive drums of the respective sensitivities are placed in a normal temperature and normal humidity environment (23 ° C., 60%
Rh), a developing device exhibiting typical developing characteristics, a developing device exhibiting high developing properties under a high temperature and high humidity environment (30 ° C., 80% Rh), and a low temperature and low humidity environment (15 ° C., 10% Rh) 3 shows the change in density of the detection image when development was performed using three developing units exhibiting development characteristics with low developability.

As can be seen from FIGS. 4 to 6, the density characteristics vary depending on the sensitivity of the photosensitive drum and the developing device used.
Conventionally, a desired density of 1.0 is controlled by controlling image forming conditions.
To find a developing bias that satisfies the condition, when the density is the highest with the same developing bias, that is, when the sensitivity of the photosensitive drum in FIG. 5 is the upper limit and the developing device is used in a high temperature and high humidity environment. Developing bias indicated by arrow A in FIG.
From 50 V, when the density is the lowest at the same developing bias, that is, when the sensitivity of the photosensitive drum in FIG. 6 is the lower limit and the developing device is used in a low-temperature and low-humidity environment, it is indicated by an arrow B in FIG. An image for detection is formed while changing the developing bias to -450 V, and the measurement of the density is repeated.
It was trying to find the required developing bias.

On the other hand, in the present invention, when the drum cartridge 100 is manufactured, information on the sensitivity of the photosensitive drum is set to N.
The sensitivity information is written in the VRAM 10 and the sensitivity
The developing bias condition used at the time of controlling the image forming condition is changed according to the result. That is, since the developing bias condition was controlled by knowing the sensitivity of the photosensitive drum 1, the control error of the developing bias was small, and the time required for the control and the amount of toner consumed could be reduced.

The following is a specific description according to the control flow shown in FIG.

In step (STEP 1), the process cartridge 10 mounted on the image forming apparatus main body 90 is
The CPU 11 reads the sensitivity information K of the photosensitive drum 1 stored in the 0 NVRAM 10. In the present embodiment, the photosensitive drum sensitivities K are grouped into ten levels of 0, 1, 2,... 9 and stored one by one at a predetermined address of the NVRAM. The sensitivity information K = 0 indicates that the exposed portion potential is -100 to 11
9V, and similarly, K = 1 is -120 to -120.
139V, K = 2 is -140 to -159V, K3 = -1
60 to -179 V, K = 4 is -180 to -199 V, K
= 5 is -200 to -219 V, K = 6 is -220 to -2
39V, K = 7 is -240 to -259V, K = 8 is -2
60 to -279 V, K = 9 represents -280 to -300 V.

Next, at step 2, the CPU 11
12, the developing bias Vbias for the photosensitive drum sensitivity K
, The developing bias Vbias at the time of control is determined.

More specifically, FIG. 8 is a graph showing the relationship between the exposure portion potential of the photosensitive drum and the developing bias at which the density of the detection image satisfies 1.0, and the horizontal axis indicating the exposure portion potential indicates the sensitivity. The range of K is also shown. For example, when K = 5, as shown in FIG. 8, the developing bias at the time of control is from -250 V to -350 V, and the developing bias is changed by 25 V between -250 V, -275 V,
A total of six voltages of -300 V, -325 V, -350 V, and -375 V may be used as the developing bias biases 1, 2, 3, 4, 5, and 6 during control.

In step 3, detection patterns (detection images) P 1, 2, 3, 4, 5 and 6 are formed using the developing biases bias 1, 2, 3, 4, 5 and 6 determined in step 2. (Print). Then, in step 4, the printed detection patterns P1, 2, 3, 4,
The densities of 5, 6 are measured by the density sensor 20, and the respective densities D1, 2, 3, 4, 5, 6 are obtained. Thereafter, in step 5, a developing bias satisfying the density 1.0 is obtained from the densities D1 to D6.

As described above, according to the present invention, the process cartridge 100 is provided with the NV
Since the RAM 10 is equipped with the sensitivity of the photosensitive drum 1 and the sensitivity of the photosensitive drum is known at the time of controlling the image forming conditions and the developing bias condition used for the image forming condition control is controlled based on the sensitivity information, the RAM 10 is particularly suitable for processing. The control error of image forming condition control at the time of cartridge replacement was small, an image with stable density could be obtained, and the time required for control and the amount of toner consumed could be reduced. Further, when the density sensor 20 is not controllable due to contamination, failure, or the like, the developing bias used at the time of actual image formation is determined based on the photosensitive drum sensitivity information of the NVRAM of the process cartridge. Can be reduced.

Embodiment 2 FIG. 9 is a sectional view showing another embodiment of the present invention.

As described above, the sensitivity fluctuation of the photosensitive drum 1 may have already occurred at the time of manufacturing.
It is well known that the sensitivity of the photosensitive drum 1 changes depending on the image forming sheet. This is because the sensitivity characteristics of the photosensitive layer of the photosensitive drum 1 are deteriorated by repeated charging and exposure, and the thickness of the photosensitive layer is reduced by the cleaning means 7 and the capacitance is changed. Conceivable. Stabilization of the characteristics irrespective of the number of printed sheets has been improved daily with stabilization of sensitivity at the time of manufacturing, but this is not yet a complete bell.

In this embodiment, therefore, a counter 13 for the number of prints (the number of prints) is installed in the image forming apparatus main body 90, and the number of prints counted by the counter 13 is provided in the process cartridge 100 by the CPU 11 in the non-volatile memory. At the time of controlling the image forming condition based on the sensitivity information of the photosensitive drum 1 as described in the first embodiment, the image forming condition is corrected by using the number of printed sheets so as to optimize the image forming condition. did. This NVR
AM10, CPU11, ROM12 and counter1
3 is shown in FIG.

The number of printed sheets will be described.
The number counted in 3 is the process cartridge 100
Is written to the NVRAM 10. This NVRAM10
Writing the number of prints to the printer for each print requires N
It is not preferable from the viewpoint of the life due to the number of writable times of the VRAM 10, and the sensitivity variation due to the number of prints of the photosensitive drum 1 usually occurs in units of several hundreds. Therefore, writing may be performed in units of 100 to 1000 sheets.

However, if the power of the apparatus main body 90 is turned off before the writing timing, the accumulated number of printed sheets is cleared.
Even if the number is within the number of writing units, NVRAM
It is preferable to perform writing to the number 10. Also, NV
Since the number of images to be written to the RAM 10 needs to be integrated, the number of images to be written is the sum of the number of images in the NVRAM before writing and the number of images to be written.

The case of writing data into the NVRAM 10 every 100 sheets will be described with reference to the flow chart shown in FIG.

After an image is formed, ie, printed, in step (STEP) 1, the number n of prints in the counter 13 is increased by a numerical value 1 in step 2. Then in step 3 CPU
11 determines whether or not the power supply of the apparatus main body is off. If the power is on, the process proceeds to step 4; if it is off, the process proceeds to step 5.

In step 4, it is determined whether the number n of prints is 100 or less. In step 5, N + n, which is the sum of the number of prints n counted so far and the total number of prints N in the NVRAM 10, is written into the NVRAM 10, and the process ends.

If it is determined in step 4 that the number n of prints is 100 or more, the process proceeds to step 6, where N + 100 obtained by adding 100 to the total number of prints N in the NVRAM 10 is calculated in the NVRAM.
Then, at step 7, the number n of printed sheets on the counter is cleared to 0, and the process returns to step 1. If the number of prints n is 100 or less in step 4, the process returns to step 1 as it is.

The total number of prints N in the NVRAM 10
Is specifically described according to the control flow shown in FIG.

In step (STEP) 1 of FIG. 12, the CPU 11 reads the sensitivity information K of the photosensitive drum stored in the NVRAM 10 of the process cartridge 100 mounted on the image forming apparatus main body, as in the first embodiment. In step 2, as in the first embodiment, the CPU 11
Refers to the table of the developing bias Vbias with respect to the photosensitive drum sensitivity K in the ROM 12 and determines the developing bias V at the time of control.
Provisionally determine bias1,2,3,4,5,6.

In step 3, the CPU 11 sets the NVRAM 1
The accumulated number of prints N stored in the memory number 0 is read, and step 4 is executed.
With reference to the table in the ROM 12 representing the variation of the exposure portion potential with respect to the total number N of printed sheets, the provisionally determined developing biases Vbias1, 2, 3, 4, 5, and 6 at the time of the control obtained in step 2 are corrected and controlled. The development bias V'bias1,2,3,4,5,6 at that time is obtained. Here, the relationship between the accumulated number of printed sheets N and the exposure portion potential will be described.

FIG. 13 is a graph showing the variation in the accumulated number of prints N and the sensitivity of the photosensitive drum, that is, the amount of potential variation with respect to the initial exposure portion potential. As can be seen from FIG. 13, as the number of printed sheets increases, the sensitivity of the photosensitive drum decreases, and the potential of the exposed portion of the photosensitive drum increases. Therefore, this relationship is stored in the ROM 12 as a table in advance, and the NVRA
The exposure section potential is actually corrected in accordance with the integrated print number N from M10.

More specifically, when the sensitivity K of the photosensitive drum at the time of manufacture stored in the NVRAM 10 is 5, the temporary developing biases Vbias1, 2, 3, 4, 5, and 6 at the time of control are -250, respectively.
V, -275V, -300V, -325V, -350
V, -375V. Here, the total number of printed sheets is 10,
In the case of 000 sheets, as shown by A in FIG. 13, the actual exposed portion potential is considered to have risen by 50 V, and this potential difference was corrected to -300 V, -325 V, -350 V, and -3.
75 V, -400 V, and -425 V may be finally used as the developing biases V'bias 1, 2, 3, 4, 5, and 6 at the time of control. If the sensitivity change depending on the number of prints differs according to the initial sensitivity of the photosensitive drum, the above table may be provided for each.

Steps 5, 6, and 7 following Step 4 are the same as those in the first embodiment. The detection patterns P1, 2, 3, 4, 5, and 6 are printed, and their densities are measured by a density sensor. The density D1,2,3,4,5,6 can be obtained, and the developing bias satisfying the density 1.0 can be obtained from the densities D1 to D6.

As described above, according to the present embodiment,
Even if the sensitivity of the photosensitive drum decreases due to the use due to the increase in the number of prints, the decrease in the sensitivity was corrected by the number of prints, so that the control accuracy of the image forming condition control was improved, and the density You can get a stable image,
The time required for control and the amount of consumed toner can be reduced. Also, the NV installed in the process cartridge
Since the total number of printed sheets is written in the RAM, it is possible to easily cope with a case where the process cartridge is replaced with another process cartridge that is not new.

The case where the developing bias is changed and controlled as the image forming condition has been described above. However, the present invention is not limited to this, and it goes without saying that the charging potential and the exposure amount may be controlled.

[0056]

As described above, according to the present invention,
At least a process cartridge having a photosensitive drum is provided with non-volatile storage means for storing information on the sensitivity of the photosensitive drum, and the stored sensitivity information is used for controlling image forming conditions. The formation conditions can be optimized. As a result, it has become possible to control the image forming conditions particularly when replacing the process cartridge by reducing the number of necessary detection images, reducing the time required for the control and the amount of toner consumed.

In addition to this, when the number of images to be formed is written in the non-volatile storage means, and the sensitivity of the photosensitive drum is corrected in accordance with the information of the number of images to be formed, the number of images to be formed is increased as the number of images is increased. Even if the sensitivity is reduced, the time required for control and the amount of toner consumed can be similarly reduced without selecting the photosensitive drum.

In any case, even when control becomes impossible, image forming conditions based on the prediction of the sensitivity of the photosensitive drum can be used, and a change in density in this case can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an embodiment of an image forming apparatus in which a process cartridge of the present invention is detachable.

FIG. 2 is a block diagram showing a connection relationship among a CPU, a ROM, and an NVRAM installed in the apparatus of FIG.

FIG. 3 is a graph showing a change in density of a detection image with respect to a developing bias when a photosensitive drum having an upper limit sensitivity is used.

FIG. 4 is a graph showing a change in density of a detection image with respect to a developing bias when a photosensitive drum having a center sensitivity is used.

FIG. 5 is a graph showing a change in density of a detection image with respect to a developing bias when a photosensitive drum having an upper limit sensitivity is used.

FIG. 6 is a graph showing a change in density of a detection image with respect to a developing bias when a photosensitive drum having a lower sensitivity is used.

7 is a diagram showing a control flow of image forming conditions in the apparatus of FIG.

FIG. 8 is a diagram illustrating a relationship between an exposure portion potential of a photosensitive drum and an appropriate developing bias.

FIG. 9 is a sectional view showing another embodiment of the image forming apparatus in which the process cartridge of the present invention is detachable.

FIG. 10 shows a CPU, ROM, and N installed in the apparatus shown in FIG.
FIG. 4 is a block diagram illustrating a connection relationship between a VRAM and a counter.

11 is a diagram showing a flow relating to writing of the total number of printed sheets in the apparatus of FIG. 9;

12 is a diagram showing a control flow of image forming conditions in the apparatus of FIG.

FIG. 13 is a diagram showing changes in the total number of printed sheets and the potential of an exposed portion.

FIG. 14 is a cross-sectional view illustrating a conventional image forming apparatus to which a process cartridge is detachably attached.

FIG. 15 is an external view of the process cartridge of FIG.

[Explanation of symbols]

 Reference Signs List 1 photosensitive drum 2 charging roller 4 developing device 6 intermediate transfer belt 7 cleaning means 10 nonvolatile storage means (NVRAM) 11 CPU 12 ROM 13 counter 20 density sensor 90 image forming apparatus main body 100 process cartridge

Claims (19)

[Claims] 1. A process cartridge detachable from a main body of an image forming apparatus, wherein the process cartridge comprises:
A process cartridge comprising: an electrophotographic photosensitive member; and a process unit acting on the electrophotographic photosensitive member; and a storage unit for storing sensitivity information of the electrophotographic photosensitive member. 2. The process cartridge according to claim 1, wherein said storage means is a nonvolatile storage means. 3. When the image forming conditions are controlled based on the density of the detection image formed on the electrophotographic photosensitive member, sensitivity information of the electrophotographic photosensitive member stored in the storage means is read, 3. The process cartridge according to claim 1, wherein the process cartridge is used for controlling the image forming conditions. 4. The image forming apparatus according to claim 1, wherein the number of image forming sheets of the process cartridge is further stored in the storing means, and the number of image forming sheets stored in the storing means is read in controlling the image forming conditions. 4. The process cartridge according to claim 3, wherein the sensitivity information of the electrophotographic photosensitive member used for the control is corrected by the number of image formation. 5. The process cartridge according to claim 1, wherein a charging unit as a process unit, a developing unit or a cleaning unit, and an electrophotographic photosensitive member are integrally formed into a cartridge, and the cartridge is detachably mountable to an image forming apparatus main body. The process cartridge according to claim 1, wherein the process cartridge is used. 6. The process cartridge, wherein at least one of a charging unit, a developing unit and a cleaning unit as a process unit and an electrophotographic photosensitive member are integrally formed into a cartridge, and this cartridge is attached to and detached from an image forming apparatus main body. The process cartridge according to claim 1, wherein the process cartridge is enabled. 7. The process cartridge according to claim 1, wherein at least a developing means as a processing means and an electrophotographic photosensitive member are integrally formed into a cartridge, and the cartridge is detachably mountable to an image forming apparatus main body. 5. The process cartridge according to any one of items 1 to 4. 8. An image forming apparatus in which a process cartridge is detachable and forms an image on a recording medium,
(A) A process cartridge having an electrophotographic photoreceptor and process means acting on the electrophotographic photoreceptor, and further having a storage means for storing sensitivity information of the electrophotographic photoreceptor, can be removed from the image forming apparatus main body. An image forming apparatus, comprising: mounting means for mounting on a recording medium; and (b) means for conveying a recording medium. 9. The image forming apparatus according to claim 8, wherein said storage unit is a nonvolatile storage unit. 10. An electrophotographic photosensitive member stored in said storage means when an image for detection is formed on said electrophotographic photosensitive member, a density is measured, and image forming conditions are controlled based on the density. The image forming apparatus according to claim 7, wherein the sensitivity information is read and used for controlling the image forming conditions. 11. The storage unit further stores the number of image formations of the process cartridge, and when controlling the image formation conditions, reads the number of image formations stored in the storage unit, and stores the image formation conditions. The image forming apparatus according to claim 10, wherein sensitivity information of the electrophotographic photosensitive member used for control is corrected based on the number of formed images. 12. An image forming apparatus having an electrophotographic photoreceptor and processing means for acting on the electrophotographic photoreceptor, comprising an image storage device for storing sensitivity information of the electrophotographic photoreceptor. Forming equipment. 13. The image forming apparatus according to claim 12, wherein said storage unit is a nonvolatile storage unit. 14. An electrophotographic photosensitive member stored in said storage means when an image for detection is formed on said electrophotographic photosensitive member, density is measured, and image forming conditions are controlled based on the density. 14. The image forming apparatus according to claim 13, wherein the sensitivity information is read and used for controlling the image forming conditions. 15. The image forming apparatus according to claim 1, further comprising: a storage unit configured to store the number of image formations of the process cartridge, and reading the number of image formations stored in the storage unit when controlling the image formation conditions. 15. The image forming apparatus according to claim 14, wherein sensitivity information of the electrophotographic photosensitive member used for control is corrected based on the number of formed images. 16. An image forming apparatus having an electrophotographic photoreceptor and a process unit acting on the electrophotographic photoreceptor, further comprising a non-volatile storage unit for storing sensitivity information of the electrophotographic photoreceptor. Image forming apparatus. 17. The image forming apparatus according to claim 16, wherein said storage unit is a nonvolatile storage unit. 18. An electrophotographic photosensitive member stored in said storage means when an image for detection is formed on said electrophotographic photosensitive member, density is measured, and image forming conditions are controlled based on the density. 18. The image forming apparatus according to claim 17, wherein the sensitivity information is read and used for controlling the image forming conditions. 19. The image forming apparatus according to claim 1, wherein the number of image forming sheets is further stored in the storage unit, and the number of image forming sheets stored in the storing unit is read to control the image forming conditions when controlling the image forming conditions. 19. The image forming apparatus according to claim 18, wherein the sensitivity information of the electrophotographic photosensitive member to be corrected is corrected by the number of formed images.