JP2001117425A - Memory medium for process cartridge, process cartridge, device and system for forming electrophotographic image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process cartridge capable of providing a stable picture quality by absorbing the individual difference of the cartridge by storing timing information for changing various process conditions while using a memory medium and by changing the process conditions together with use information accumulated with the use of the cartridge, a device, to and from which the process cartridge is freely attachable an detachable, and a system for forming electrophotographic image. SOLUTION: On a memory medium 22 provided in a process catridge C, information on parameter values for changing condition intrinsic to respective process cartridges is stored as information for changing image forming process conditions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus using an electrophotographic method, such as a laser beam printer, a copying machine, a facsimile, etc., a process cartridge mounted on the image forming apparatus, and a process cartridge. The present invention relates to an electrophotographic image forming system for forming an image on a recording medium and a memory medium for a process cartridge mounted on a process cartridge.

Here, a process cartridge is a cartridge in which at least one of a charging unit, a developing unit and a cleaning unit and an electrophotographic photosensitive member are integrally formed into a cartridge, and this cartridge is detachably mountable to an electrophotographic image forming apparatus main body. Or, at least the developing means and the electrophotographic photosensitive member are integrally formed into a cartridge, and this cartridge is made detachable from the main body of the electrophotographic image forming apparatus.

[0003]

2. Description of the Related Art An electrophotographic image forming apparatus such as a copying machine or a laser beam printer irradiates a light corresponding to image information to an electrophotographic photosensitive member to form a latent image, and develops the latent image on the latent image by developing means. An image is formed on a recording paper by supplying a developer (toner) as a recording material to visualize the image, and further transferring the image from a photoconductor to a recording medium such as a recording paper.

In such an image forming apparatus, a cleaning unit including a toner storage unit, a developing unit, a photoconductor, a charging unit, and a waste toner container is used for the purpose of simplifying replacement maintenance of consumables such as a photoconductor and toner. And the like are often integrated as a process cartridge and are configured to be detachable from the image forming apparatus. Further, when a developing device of a plurality of colors is used and a developing condition of each developing device is different, as in a color image forming apparatus, or when a developing condition of a photosensitive drum is different from a developing condition of a developing device, a developing cartridge of each color is used. There are also photoconductor cartridges in which the cleaning means and the photoconductor drum are integrated, which are individually formed as process cartridges.

[0005] Some cartridges are provided with storage means (memory) to manage cartridge information.
As described in U.S. Pat. No. 5,272,503, a cartridge may be used to store the amount of cartridge used to change various process conditions. For example, the charging current value is switched or the exposure amount is adjusted. These cartridges have the same control as long as the used amount is the same, although the cartridges are different.

[0006]

However, when the image forming system becomes complicated, differences in the characteristics of the individual cartridges may occur due to instability in the image quality such as the production lot of the photoreceptor and toner and color difference. . Therefore, the conventional techniques described above are not sufficient to correct the change in image quality in all cartridges.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and uses a memory medium to store timing information for changing various process conditions, and to accumulate the timing information as the cartridge is used. A process cartridge capable of absorbing a difference between individual cartridges and providing a stable image quality by changing a process condition in accordance with the used amount information, an image forming apparatus and an image forming system in which the process cartridge is detachable It is to provide.

It is another object of the present invention to provide a process cartridge memory medium which is mounted on a process cartridge, stores information on the process cartridge, and transmits the stored contents to the image forming apparatus main body.

[0009]

The above object is achieved by a process cartridge according to the present invention, an image forming apparatus and an image forming system in which the process cartridge is detachable, and a memory medium for the process cartridge.

According to the first aspect of the present invention, the electrophotographic photoreceptor and at least one of the process means acting on the photoreceptor are integrally unitized and mounted on a process cartridge detachable from the image forming apparatus main body. In a memory medium for a process cartridge that stores information about the process cartridge and transmits the stored content to the image forming apparatus main body, the image forming apparatus main body includes:
Means for reading and writing the storage contents of the memory medium, means for statistically calculating the amount of use of the cartridge mounted on the image forming apparatus main body, and based on the used amount and the storage information of the memory medium. And control means for changing the image forming process conditions.In the memory medium, as the information for changing the image forming process conditions, information on a parameter value for changing a condition specific to each process cartridge is stored. A memory medium for a process cartridge characterized by being stored is provided. According to the present invention, the timing for changing the process conditions can be set in the memory in accordance with the characteristics of each cartridge, so that it is possible to supply a stable image without variations in each cartridge.

According to an embodiment of the first aspect of the present invention, the parameter value for changing the condition specific to the process cartridge is information written according to the characteristics of each cartridge when the cartridge is manufactured. According to another embodiment, the parameter value for changing the condition specific to the process cartridge further includes information on the characteristics of the parts constituting each cartridge and / or the process value for changing the process condition according to the usage amount. This is information including threshold information. According to another embodiment, the memory medium for the process cartridge may further include information for identifying each cartridge individual. Therefore, according to the present invention, the change of the cartridge can be reliably recognized on the main body side, so that the calculation of the used amount becomes accurate, and a stable image can be supplied. According to still another embodiment, when the process cartridge is mounted on the image forming apparatus main body, the process cartridge faces an antenna unit provided on the image forming apparatus main body with a gap,
Information communication with the antenna means can be performed by electromagnetic waves, and therefore, the present invention can set the timing of changing the process conditions according to the characteristics of each cartridge stored in the memory. In addition to being able to supply stable images without variations, the need for a connector for connection between the memory and the image forming apparatus main body is eliminated, so that the stability of information communication is increased and stable images are supplied. Can be.

According to a second aspect of the present invention, there is provided a process cartridge wherein an electrophotographic photosensitive member and at least one of process means acting on the photosensitive member are integrally unitized to be detachable from an image forming apparatus main body. In a process cartridge, comprising: a memory for storing information on a process cartridge; and a transmission unit for transmitting the storage content of the memory to the image forming apparatus main body, wherein the image forming apparatus main body includes a memory of the process cartridge. Means for reading and writing the stored contents, means for statistically calculating the amount of use of the cartridge mounted on the image forming body, and image forming process conditions based on the used amount and the storage information of the memory. Control means for changing the image forming process conditions in the memory. As information for, the process cartridge, wherein the information about the parameter value for at least each of the process cartridges specific condition change are stored is provided. According to the present invention, the timing for changing the process conditions can be set in the memory in accordance with the characteristics of each cartridge, so that it is possible to supply a stable image without variations in each cartridge.

In one embodiment of the present invention, the parameter value for changing the condition specific to the process cartridge is information written to the memory according to the characteristics of the cartridge when the cartridge is manufactured. . According to another embodiment, the parameter value for changing the condition specific to the process cartridge further includes a threshold value for changing the process condition according to the information on the characteristics of the parts constituting each cartridge and / or the usage amount. This is information including information. According to another embodiment, the memory may further include information for identifying each cartridge individual, and therefore, it is possible to reliably recognize that the cartridge has been changed on the main body side. Is accurate, and a stable image can be supplied. According to still another embodiment, when the process cartridge is mounted on the main body of the electrophotographic image forming apparatus, the transmitting means included in the process cartridge has a gap with an antenna unit provided on the main body of the electrophotographic image forming apparatus. And information communication between the memory means and the antenna means can be performed by electromagnetic waves,
Since the timing for changing the process conditions can be set according to the characteristics of each cartridge stored in the memory, it is possible to supply a stable image while eliminating variations in individual cartridges, and in addition to the memory and the image forming apparatus. Since there is no need for a connector for connecting the main unit,
The stability of information communication is increased, and a stable image can be supplied.

According to a third aspect of the present invention, there is provided an electrophotographic image forming apparatus capable of detachably attaching a process cartridge and forming an image on a recording medium, comprising: (a) and (i) an electrophotographic photosensitive member; A process cartridge in which at least one of the process means acting on the unit is integrally unitized, (ii) a memory in which information on at least parameter values for changing conditions unique to each process cartridge is stored, and (iii) Mounting means for detachably mounting a process cartridge having cartridge transmitting means for transmitting the contents stored in the memory to the image forming apparatus main body; and (b) mounting the process cartridge on the mounting means. The stored contents are communicated through the cartridge transmitting means of the process cartridge. And (c) statistically calculating an amount of the process cartridge used in the image forming apparatus main body, and based on the used amount and information received by the apparatus main body transmission means. And a control unit for changing image forming process conditions. According to the present invention, the timing for changing the process conditions can be set in accordance with the characteristics of each cartridge stored in the memory. Therefore, it is possible to supply a stable image without variations in individual cartridges.

According to an embodiment of the present invention, when the process cartridge is mounted on the mounting means, the apparatus main body transmitting means may have a gap with the cartridge transmitting means of the process cartridge. And antenna means for communicating the contents stored in the memory with the cartridge transmitting means. According to this configuration, the process condition change timing can be set in accordance with the characteristics of each cartridge stored in the memory, so that a stable image can be supplied without variations in individual cartridges. Since a connector for connecting the memory and the image forming apparatus main body is not required, the stability of information communication is increased, and a stable image can be supplied.

According to the fourth aspect of the present invention, by using a process cartridge detachable from an electrophotographic image forming apparatus main body,
An electrophotographic image forming system for forming an image on a recording medium, wherein (a) and (i) a process cartridge in which at least one of a photoconductor for electrophotography and process means acting on the photoconductor is integrally unitized. (Ii) a memory in which at least information relating to the used amount of the process cartridge and information relating to parameter values for changing conditions specific to each process cartridge are stored;
(iii) a process cartridge having cartridge transmitting means for transmitting the contents stored in the memory to the image forming apparatus main body, and (b) when the process cartridge is mounted on the image forming apparatus main body, (C) statistically calculating an amount of the process cartridge used in the image forming apparatus main body and communicating the stored contents through the cartridge transmitting means of the process cartridge; An electrophotographic image forming system, comprising: a control unit that changes an image forming process condition based on an amount and information received by the apparatus main body transmitting unit. According to the present invention, the process condition change timing can be set according to the characteristics of each cartridge stored in the memory.
A stable image can be supplied.

According to an embodiment of the fourth aspect of the present invention, when the process cartridge is mounted on the image forming apparatus main body, the apparatus main body transmitting means includes the cartridge transmitting means of the process cartridge. Antenna means which faces with a gap and communicates the stored contents of the memory with the cartridge transmitting means. According to this configuration, the process condition change timing can be set in accordance with the characteristics of each cartridge stored in the memory, so that a stable image can be supplied without variations in individual cartridges. Since a connector for connecting the memory and the image forming apparatus main body is not required, the stability of information communication is increased, and a stable image can be supplied.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a process cartridge, an image forming apparatus and an image forming system in which a process cartridge is detachable, and a memory medium for a process cartridge according to the present invention will be described in more detail with reference to the drawings. .

Embodiment 1 First, referring to FIGS. 1 and 2,
An embodiment of an electrophotographic image forming apparatus to which a process cartridge configured according to the present invention can be mounted will be described. In this embodiment, the electrophotographic image forming apparatus is a laser beam printer that receives image information from a host computer and outputs an image, and the laser beam printer is a drum-shaped electrophotographic photosensitive member, that is, a photosensitive drum. This is an image forming apparatus in which consumables such as a developer are detachable from a main body as a process cartridge and are replaceable. First, an electrophotographic image forming apparatus and a process cartridge according to the present embodiment will be described with reference to FIGS.

In this embodiment, the process cartridge C
Is a photosensitive member having a drum shape, that is, a photosensitive drum 1, and a contact charging roller 2 for uniformly charging the photosensitive drum 1.
A developing sleeve 5 which constitutes a developing means opposed to the photosensitive drum 1; a developer container 4 which accommodates a developer T rotatably supporting the developing sleeve 5; and a cleaning blade 10 which constitutes a cleaning means And a waste toner container 6 that stores the residual toner removed from the photosensitive drum 1 by the cleaning blade 10. The process cartridge C is detachably mounted on a mounting means 101 (FIG. 2) provided in the image forming apparatus main body 100 by a user.

The developing sleeve 5 in the developing means is a sleeve made of non-magnetic aluminum having a diameter of 16 mm, the surface of which is coated with a resin layer containing conductive particles. Although not shown, a four-pole magnet roll is arranged in the developing sleeve 5. A developer blade, that is, a developer regulating member 7 is attached to the developer accommodating container 4. In this embodiment, the developer regulating member 7 is made of silicone rubber having a JIS hardness of about 40 ° and has a contact force of 30 to 40 gf / cm against the developing sleeve 5 (per 1 cm in the longitudinal direction of the developing sleeve 5). Abutment load)
It is abutted so that it becomes.

In this embodiment, a negatively chargeable magnetic one-component toner (hereinafter simply referred to as “toner”) is used as the developer T stored in the developer storage container 4. As components, 100 parts by weight of a styrene n-butyl acrylate copolymer as a binder resin, 80 parts by weight of magnetic particles, 2 parts of a negative charge control agent of a monoazo iron complex, and 3 parts of low molecular weight polypropylene as a wax at 140 ° C. Melted and kneaded with a heated twin-screw extruder, coarsely pulverized the cooled kneaded material with a hammer mill, finely pulverized the coarsely pulverized material with a jet mill, and air-classified the obtained finely pulverized material to obtain a weight average A classified powder having a diameter of 5.0 μm is obtained. 1.0 parts by weight of hydrophobic silica fine powder was mixed with a classified product having an average particle size of 5.0 μm using a Henschel mixer,
Obtain a developer. And the weight average particle size is 3.5 to 7.0.
Those having a range of μm (mainly about 6 μm) are used.

The developing bias applied to the developing sleeve 5 is, for example, a DC voltage of -450 when the gap between the photosensitive drum 1 and the developing sleeve 5 is about 300 μm.
V, AC voltage: rectangular wave Vpp 1600 V, frequency 220
0 Hz is applied.

A toner agitating means 8 is provided in the developer container, that is, the toner container 4, and rotates at a rate of once every 6 seconds to loosen the toner T in the toner container 4 and transfer the toner to the developing area. Sending.

The charging roller 2 is formed by forming a conductive elastic body on the surface of a metal core. Both ends of the metal core are rotatably held, and are pressed against the outer peripheral surface of the photosensitive drum 1 with a predetermined pressing force. Then, the photosensitive drum 1 is driven to rotate. A superimposed voltage of an AC component Vac and a DC component Vdc having a peak-to-peak voltage Vpp that is twice or more of a charging start voltage is applied to the charging roller 2 from a high-voltage power supply provided in the image forming apparatus main body 100 via a metal core. Vac + Vdc) is applied to the charging roller 2 so that the outer peripheral surface of the photosensitive drum 1 being driven to rotate is A
Contact charging is uniformly performed by the C application method.

The charging bias applied to the charging roller 2 is as follows: DC voltage: -600 V, AC voltage: sine wave Vpp2
KV, frequency = 1500Hz, effective current value = 1400μ
A is applied. The charging potential of the photosensitive drum 1 is Vd = -6.
00V, and the potential of the laser exposure part is set to VL = −15.
The voltage is set to 0 V, whereby the laser exposed portion (VL portion) is subjected to reversal development.

FIG. 2 shows a schematic configuration of a laser printer L as an image forming apparatus. The cylindrical photosensitive drum 1 serving as a latent image carrier rotates around an axis supported by the apparatus main body 100 as an arrow. After the surface of the photosensitive drum 1 is uniformly charged by the charging roller 2, a latent image is formed by the exposure device 3. The latent image formed on the photosensitive drum 1 is visualized by supplying toner T by a developing sleeve 5 constituting a developing device. A bias supply power source (not shown) in which an AC bias is superimposed on a DC bias is connected between the photosensitive drum 1 and the developing sleeve 5 so as to apply an appropriate developing bias.

The toner image on the photosensitive drum 1 visualized by the toner T as described above is transferred by the transfer roller 9 to a recording medium 20 such as a recording paper. Recording medium 2
0 is fed by a feed roller 21 and sent to a transfer roller 9 in synchronization with an image on the photosensitive drum 1 by a registration roller (not shown). Then, the visible image formed by the toner T transferred to the recording medium 20 is conveyed to the fixing device 12 together with the transfer material 20 and fixed by heat or pressure to become a recorded image. On the other hand, the photosensitive drum 1 is not transferred after the transfer.
The remaining toner T is removed by the cleaning blade 10 and stored in the waste toner container 6. Thereafter, the surface of the photosensitive drum is charged again by the charging device 2, and the above-described steps are repeated.

Next, the memory medium for the process cartridge mounted on the process cartridge, that is, the memory will be described.

In the case of this embodiment, the cartridge C has a memory 22 and a cartridge-side transmitting section 23 for controlling reading and writing of information from and to the memory 22 on the lower side of the waste toner container 6. When the cartridge C is mounted on the image forming apparatus main body 100, the cartridge transmitting section 23 and the transmitting section 14 (FIG. 5) on the image forming apparatus main body side are arranged to face each other.

The memory 22 used in the present invention includes:
A normal semiconductor electronic memory can be used without any particular limitation. In particular, in the case of a non-contact memory in which data communication between the memory 22 and the read / write IC is performed by electromagnetic waves, the cartridge-side transmission unit 23 and the apparatus body-side transmission unit 14 may be in a non-contact state. The possibility of contact failure due to the mounting state of C is eliminated, and highly reliable control can be performed.

The two transmission sections 23 and 14 constitute a control transmission section for reading and writing information in the memory 22. As for the capacity of the memory 22, it is assumed that the memory 22 has a capacity enough to store a plurality of pieces of information such as individual identification information of the cartridge C and cartridge characteristic values to be described later.

A feature of the present invention resides in that information stored in the memory 22 has at least information on parameter values for changing process conditions specific to each cartridge.

The parameter values are, for example, values written according to the characteristics of parts used individually for each cartridge when the cartridge is shipped. For example, the parameter values of the photosensitive drum 1, the toner T, the developing sleeve 5, and the charging roller 2 It may be a value determined according to the manufacturing lot or the sensitivity of the photosensitive drum 1, or may be threshold information of the cartridge usage amount for changing the process conditions determined by the combination of each component.

These pieces of information are used to determine the timing and value for changing the process conditions of the image forming apparatus main body 100.

More specifically, the high-voltage output supplied to the processing means is referred to by referring to both the usage information of the cartridge statistically processed in the image forming apparatus main body 100 and the parameter value information in the memory 22. And the process speed and the amount of laser light.

Next, control of image forming process conditions in this embodiment will be described.

In this embodiment, a charging AC application method using a charging roller 2 is used as a charging means. Therefore,
Since the positive and negative voltages are alternately applied and the discharge / reverse discharge is repeated, the surface of the photosensitive drum 1, which is the member to be charged, is greatly deteriorated due to the discharge. It is scraped off by friction with the contact member.

For this reason, the photosensitive layer of the photosensitive drum 1 gradually becomes thinner with use of the apparatus, and when the photosensitive layer reaches the limit thickness, the function as the photosensitive layer is reduced, and minute charging unevenness may occur. In addition, poor charging occurs due to a decrease in the charge holding ability of the surface. Therefore, the lifespan of the image forming apparatus and the process cartridge is determined by the number of prints used until the photosensitive layer of the photosensitive drum 1 is worn to the limit thickness.

It is also known that when the amount of discharge is excessively reduced, minute black spots called sand are generated on an image, and the discharge tends to be unstable. The above-mentioned sandy ground is a black spot-like image generated in a portion of the output image developed by the reversal developing system in which the discharge amount of the charging roller 2 is small and thus the photosensitive drum 1 is not sufficiently charged. It is known that such a sandy image is remarkably generated when the peak-to-peak voltage of the vibration voltage applied to the charging roller 2 is small.

Therefore, in order to achieve both high image quality and a long service life of the image forming apparatus and the process cartridge, the photosensitive layer of the photosensitive drum 1 must have a thickness enough to maintain the sharpness of the latent image. It is necessary to use a proper discharge amount to prevent sandy ground due to under-discharge and to reduce photoconductor deterioration.

As for the method of controlling the voltage applied to the contact charging member such as the charging roller 2, the charging roller 2 is moved from the photosensitive drum 1 by constant current control or the like as in the prior art.
A method is used in which the amount of current flowing through is controlled to be constant.

Therefore, the relationship between the photoreceptor shaving amount and the total charging current amount, and the relationship between the total charging current amount when the sand disappears and the number of printed sheets were examined below.

FIG. 3 shows the relationship between the photoconductor shaving amount Δd (μm / sheet) and the total charging current Itotal. From this, it can be seen that the photoconductor shaving amount Δd decreases as the charging total current amount Itotal decreases.

The thickness d of the photoreceptor is measured by a film thickness measuring device (Fi).
This is the actual film thickness measured using a permascope E-111 manufactured by Scher.

FIG. 4 shows the relationship between the number of printed sheets and the total charging current Itotal when the sand image disappears. Thus, the total charging current Itota in the region A and the region B is calculated.
It can be seen that 1 fluctuates. These variations, ie,
It is considered that the occurrence of sand is caused by the charging roller 2 and the thickness of the photoconductor.

The region A is mainly caused by the charging roller, and the charging roller 2 is contaminated by the external additive of the toner, the reversal toner and the paper powder, the charging ability fluctuates, and the current amount decreases.

The area B is mainly caused by the photoreceptor. As the printing operation is repeated, the surface of the photoreceptor drum 1 is gradually removed, and the thickness of the photoreceptor layer on the surface of the photoreceptor drum becomes thinner. When the thickness of the photoreceptor is reduced, the impedance of the photoreceptor decreases, and the voltage applied to the photoreceptor drum 1 at the time of charging increases.

From the above, in order to extend the life of the photosensitive drum 1 without deteriorating the quality of the image, it is best to set the minimum charging current value which does not cause an adverse effect on the image at a certain number of prints. For this purpose, the charging current value must be set in consideration of the state of the charging roller 2 and the state of the thickness of the photosensitive layer of the photosensitive drum 2.

The state of the charging roller 2 and the thickness of the photosensitive drum 1 depend on the characteristics of each component used in the cartridge and the amount of the cartridge used.

Therefore, in this embodiment, (1) the process cartridge C is
The time driven within 0 is calculated by an arithmetic expression to obtain an integrated value of the used amount. This value will be referred to as “drum usage” hereinafter. (2) The process cartridge C is provided with the memory 22, and the threshold information of the used amount determined by the combined characteristics of the photosensitive drum 1 and the charging roller 2 used in each cartridge and the characteristics of the photosensitive drum 1 The coefficient information of the determined arithmetic expression is stored. (3) In the image forming apparatus main body 100, the used amount of the cartridge is calculated based on the driving time of the cartridge measured by the main body 100 and the coefficient information stored in the memory 22 of the cartridge, and the integrated value of the used amount is stored. The current value applied to the charging roller 2 when the integrated value reaches the threshold value stored in the memory 22 of the cartridge is changed. Is performed.

Here, the threshold information stored in the memory 22 of the cartridge C may be plural, and the switching of the charging current value may be performed plural times. As a result, it is possible to perform charging with the minimum necessary charging current value while maintaining image quality, and the life of the photosensitive drum 1 is extended.

The overall configuration of the image forming system according to the present embodiment will be described with reference to FIGS.

As shown in FIG. 5, the main body control unit 24 includes a data storage memory 13, a control unit 25, a calculation unit 26, a photoconductor rotation instruction unit 27, and a charging bias application time detection unit 2.
8, a main body transmission unit 14 and the like. Also, cartridge C
, A memory 22 and a transmission unit 23 are arranged.

Next, as shown in FIG.
In the memory 22, the drum use amount calculation formula coefficient: φ, the drum use amount calculation formula threshold: α, the cartridge individual information: X
(Hereinafter, referred to as “ID information”). Here, the ID information is for detecting in the image forming apparatus main body 100 whether or not the cartridge C has been replaced, and may be any information as long as the information is different for each cartridge. Specifically, the serial number or the like of the cartridge C is used.

The threshold value α and the coefficient φ are stored in the memory 2 at the time of shipment.
2 is stored. These values change depending on the sensitivity of the photosensitive drum, the drum material, the surface condition of the charging roller 2, and the like.

Next, the control operation in this embodiment will be described.

When the print signal is received by the image forming apparatus main body 100, the cartridge is driven by the photoreceptor rotation instruction unit 27, and the image forming process is started. At this time, the drum usage is calculated as follows.

The data B obtained by integrating the photosensitive rotation time data from the photosensitive rotation instructing section 27, the data A obtained by integrating the charging bias application time data from the charging bias application time detecting section 28, and the weights read from the memory 13 The calculation unit 26 calculates the drum usage D according to a conversion formula D = A + B × φ using the coefficient φ, and accumulates and stores it in the memory 13 in the apparatus main body 100.

The drum use amount D accumulated and stored is stored in the control unit 2.
5 is compared with a threshold value α in the memory 22 of the cartridge C.

As a result of the comparison, when the drum use amount D becomes larger than the value of α, the control unit 25 sends the charging bias power supply 29
And the control bias is changed.

As long as the ID information X is not changed, accumulation of the drum usage D is continued. If it is recognized that the ID information X has been changed, it is determined that the cartridge has been replaced, and the drum usage D is reset.

The photoconductor rotation time data and the charging bias application time data are stored in the memory 22 as needed, and the calculation of the drum usage data is performed as needed when the driving of the photoconductor drum 1 is stopped.

Next, the operation of the image forming apparatus of this embodiment will be described with reference to the flowchart of FIG.

The operation of the image forming apparatus is started (STA)
RT). The following steps (S) 101 to 112 are performed. That is, S101: the power of the image forming apparatus main body is turned on. S102: Check the cartridge ID information to determine whether the cartridge has been changed. S103: If the ID has been changed, the drum usage data is reset to 0. S104: The print signal is turned ON. S105: The photoconductor rotation time detector 27 starts counting the photoconductor rotation time. S106: The charging bias application time detecting section 28 starts counting the charging bias application time. S107: The coefficient φ is read from the memory 22 of the process cartridge C. S108: The calculation unit 26 calculates the drum usage D. S109: The drum usage amount D is stored in the memory 13 of the apparatus main body 100. S110: The control unit 25 reads the threshold α. S111: The control unit 25 compares the drum usage data D with the threshold α. If “YES” is determined, S112
If the determination is "NO", the process returns to S104 and repeats. S112: A switching signal is transmitted from the control unit 25 to the charging bias power supply 29 shown in FIG. 5, and the charging current value changes. In this embodiment, the charging current value is changed from 1400 μA to 1250 μA when the charging current reaches the threshold value α.

Thus, the control operation is completed (EN
D).

As described above, by performing the current value control as shown in the above-mentioned flowchart and the solid line in FIG. 8, the life of the drum is increased up to 13,000
In this case, it is possible to charge the photosensitive drum 1 with the minimum necessary charging current value while maintaining the image quality, and it is possible to extend the life of the photosensitive drum 1.

In the present embodiment, the switching of the current value is performed only once. However, the current value may be changed in a plurality of stages according to individual characteristics, and the current value may be increased or decreased depending on the state of each cartridge. The drum usage data threshold is
It has only one, but you may have more than one.

FIG. 9 shows information in the memory 22 when a plurality of drum usage data thresholds are provided. Various kinds of information are stored in the memory 22. In the present embodiment, at least the cartridge ID information: X, the drum use amount calculation formula coefficient: φ, and the drum use amount calculation expression thresholds: α ₁ , α ₂ , α ₃ It is assumed that the three thresholds are stored. These are always in a state where they can be transmitted / received to / from the calculation unit 26 in the main body control unit 24, and are calculated based on these information, and the control unit 25 performs data collation.

Note that FIGS. 10 and 11 show flowcharts when switching is performed a plurality of times.

The operation of the image forming apparatus is started (STA)
RT). The following steps (S) 201 to 218 are performed. That is, S201: the power of the image forming apparatus main body is turned on. S202: Check the cartridge ID information to determine whether the cartridge has been changed. S203: If the ID has been changed, the drum usage data is reset to 0. S204: The print signal is turned on. S205: The photoconductor rotation time detector starts counting the photoconductor rotation time. S206: The charging bias application time detecting section starts counting the charging bias application time. S207: The coefficient φ is read from the memory 22 of the process cartridge. S208: The calculation unit 26 calculates the drum usage D. S209: The drum usage amount D is stored in the memory 13 of the main body. S210: The control unit 25 reads the threshold α. (Hereinafter, the processing from S204 to S210 will be referred to as “calculation processing.”) S211: The control unit 25 uses the drum usage data D and the threshold α.
Compare ₁ If “YES” is determined, S212
If the determination is “NO”, the process returns to S204. S212: STEP in the bias table stored in advance in the control unit 25 is reduced by one stage, and a signal for switching is transmitted from the control unit 25 to the charging bias power supply 29 shown in FIG. Proceed to. S213: The arithmetic processing is performed in the memory 22 and the main body control unit 24. S214: The control unit 25, calculated drum usage data determines whether or reached the threshold value alpha ₂ stored in the memory. If “YES” is determined, the process proceeds to S215, and if “NO”, the process returns to S213. S215: The STEP of the bias table stored in advance in the control unit 25 is lowered by one step, a switching signal is transmitted from the control unit 25 to the charging bias power supply 29 shown in FIG. 5, and the charging current value changes. S216: The arithmetic processing is performed in the memory 22 and the main body control unit 24. S217: The control unit 25, calculated drum usage data to determine whether reached the threshold value alpha ₃ stored in the memory. If “YES” is determined, the process proceeds to S218,
If “NO” is determined, the process returns to S216. S218: The step of the bias table stored in the control unit 25 in advance is lowered by one step, a switching signal is transmitted from the control unit 25 to the charging bias power supply 29 shown in FIG. 5, and the charging current value changes.

Thus, the control operation is completed (EN
D).

Although the above description has been given of the case where there are three types of switching threshold information, it is apparent that more switching may be performed in the spirit of the present invention.

Second Embodiment Next, a second embodiment according to the present invention will be described. In the second embodiment, since the configurations of the image forming apparatus and the process cartridge are the same as those in the first embodiment, the description is omitted here.
Only the features of the present invention according to the present embodiment will be described.

In the first embodiment, the charging current amount is changed by using the drum usage amount as the usage amount data in the memory 22, and using the drum usage amount calculation expression coefficient and the drum usage amount calculation expression threshold as the characteristic values. However, the present embodiment is characterized in that the data of the first embodiment is further managed using the drum sensitivity information as a characteristic value, and the charging and developing DC voltage is changed.

Conventionally, it is known that the line width at the time of image formation tends to be narrower than in the "initial use state" of the developing device (only when a large amount of toner is present in the toner container, compared to when printing progresses). Fig. 12 shows 600 dpi /
It shows the durability transition of the width of the 4-dot line. Following this solid line, it can be seen that the line width rises up to around the initial 1K (1000 sheets).

Although various causes can be considered for this, mainly the instability of the charge amount of the toner in the initial state and the instability of the initial VL potential of the photoconductor are mentioned. Especially VL
The transition changes depending on the paper passing mode, and the latent image is faithfully reproduced by development. In an initial state where the potential fluctuation is large, a phenomenon that the line width becomes narrow occurs.
Also, the drum sensitivity, that is, the VL potential fluctuates depending on the production lot of the photoconductor.

Therefore, in the present embodiment, (1) As in the first embodiment, the time during which the cartridge is driven by the image forming apparatus main body 100 is obtained by an arithmetic expression. Similar to the first embodiment, it is called “drum usage”. (2) A memory is provided in the process cartridge, and threshold information, change coefficient information, and drum sensitivity information relating to the line width change of the drum usage data determined by the characteristics of the photoconductor and the charging roller are stored in the memory. (3) An initial charging DC bias and an initial developing DC bias corresponding to each cartridge are determined based on the drum sensitivity information. After that, the cartridge use amount is calculated based on the charging bias application time measured by the main body, the photoconductor driving time, and the coefficient information, and when the value reaches the threshold value stored in the memory, the charging DC bias and the developing DC bias are turned off. Change. Is performed. As a result, a stable line width transition can be obtained, and high image quality can be realized.

Referring to FIGS. 13 and 14, the configuration of the image forming system in this embodiment will be described.

As shown in FIG. 13, the main body control unit 64 includes a data storage memory 13, a control unit 65, a calculation unit 66, a photoconductor rotation instruction unit 67, a charging bias application time detection unit 68,
It has a main body transmission unit 14. Also, on the cartridge C side,
A memory 62 and a transmission unit 63 are provided.

Next, as shown in FIG. 14, in the memory 62, there are used amount calculation formula coefficients: φ, calculation formula thresholds: β, γ, sensitivity thresholds: L, M, H, and the same as in the first embodiment. Stores cartridge individual identification information: X. The threshold values β and γ, the coefficient φ, and the drum sensitivity information are stored in the memory 62 at the time of shipment. These values are set to optimal values according to the characteristics of the photosensitive drum and other components used in the cartridge.

The information contents are always in a communicable state through the transmission means 63 and 14, and are calculated based on the information and the control unit 65 performs data collation.

Next, the control operation in this embodiment will be described.

FIG. 15 shows the relationship between the contrast potential and the line width. Here, the contrast potential represents the absolute value of the potential difference between the potential of the DC component of the developing bias and the potential of the light portion of the drum.

As can be seen from FIG. 15, both have a good correlation, and the amount of change in line width per 10 V of contrast potential is 2 to 5 (μm / 10 V). Therefore,
It can be seen that it is sufficient to control the contrast potential in order to correct the sensitivity of the photosensitive drum 1 and the line width that varies depending on the use state of the cartridge C.

In this embodiment, as a means for changing the contrast potential, a method of changing the DC voltage value of the developing bias was selected.

The actual control operation will be described.

The cartridge C is the main assembly 100 of the image forming apparatus.
, The drum sensitivity information is read by the access from the control unit 65.

In the present embodiment, the drum sensitivity information is divided into three stages of L, M and H according to the light portion potential at the time of shipping of the drum, and the width of each potential is as follows. H = -120V, M = -120--170V, L
= -170V or more.

Based on this information, an initial developing bias setting is set by the developing DC bias power supply 71 through the control unit 65. In this embodiment, -5 when the sensitivity is L
10 V, -490 V when the sensitivity was M, and -470 V when the sensitivity was H.

Next, when a print signal is received by the apparatus main body 100, the cartridge C is driven by the photoreceptor rotation instruction section 67, and the image forming process is started. At this time, similarly to the first embodiment, the drum usage is calculated as follows.

A result B obtained by integrating the photosensitive rotation time data from the photosensitive rotation instructing section 67, a result A obtained by integrating the charging bias application time data from the charging bias application time detecting section 68, and a weighting coefficient read from the memory The drum use amount D is calculated by the calculation unit 66 by the conversion formula D = A + B × φ using φ, and is accumulated and stored in the memory 13 in the main body.

The accumulated drum usage D is calculated by the arithmetic unit 6
6 is compared with threshold values β and γ in the memory 62 of the cartridge C. Here, the threshold values β and γ are set to β <γ.

As a result of the comparison, when the drum usage D first becomes larger than β, the developing bias value is lowered by 20 V from the initial value by the developing DC bias power supply 71 through the control unit 65. Specifically, the sensitivity is -490 V when the sensitivity is L, -470 V when the sensitivity is M, and -450 V when the sensitivity is H.

Further, when the use of the cartridge C progresses and the usage amount D of the photosensitive drum 1 becomes larger than γ, the developing DC is switched by the developing DC bias power supply 71 through the control unit 65 in the direction of further lowering the developing bias by 20V. Specifically, when the sensitivity is L, -470V, and when the sensitivity is M, -450V.
In the case of V and H, it is -430V.

The photoconductor rotation time data and the charging bias application time data are stored in the memory 62 as needed, and the calculation of the drum usage data is performed as needed when the driving of the photoconductor drum 1 is stopped.

Further, the operation of the image forming apparatus of this embodiment will be described with reference to the flowcharts of FIGS.

The operation of the image forming apparatus is started (STA
RT). The following steps (S) 301 to 344 are performed. That is, S301: the power of the image forming apparatus main body is turned on. S302: The sensitivity information is read from the memory 62 to the control unit 65. S303: The control unit 65 checks the photosensitive drum sensitivity information in the memory 62. Here, if the sensitivity is L, S304
If the sensitivity is M, proceed to S305. If the sensitivity is H, proceed to S305.
Proceed to 306. S304: Since the sensitivity is L, the initial developing bias is set to-
510V. S305: Since the sensitivity is M, the initial developing bias is set to-
490V. S306: Since the sensitivity is H, the initial developing bias is set to-
470V. S307: The initial developing bias is determined. S308: Check the cartridge ID information to determine whether the cartridge has been changed. S309: If the ID has been changed, the drum usage data is reset to 0. S310: The values of β and γ are read from the memory 62. S311: Compare drum usage D data with β value. Here, if D> β, the process proceeds to S312, otherwise, S3
Proceed to 25. S312: The drum usage amount D data is compared with the γ value. Here, if D> γ, the process proceeds to S313; otherwise, S3
Proceed to 14. S313: If the drum usage amount D when the power is ON is D> γ, the developing bias is lowered by −40 V here, and the control is ended. S314: If the drum usage amount D when the power is on is D> β and is not more than γ, the developing bias is lowered by −20 V here, and the process proceeds to S315. S315: Set to the print ready state. S316: The print signal is turned ON. S317: The photoconductor drum rotation time detector starts counting the photoconductor drum rotation time. S318: The charging bias application time detecting unit starts counting the charging bias application time. S319: The coefficient φ is read from the memory 62 of the process cartridge C. S320: The calculation unit 66 calculates the drum usage D. S321: The drum usage D is stored in the memory 13 of the apparatus main body 100. S322: The control unit 65 reads the threshold value γ. S323: The control unit 65 sets the drum usage data D and the threshold γ
Compare. If “YES” is determined, the process proceeds to S324, and if “NO”, the process returns to S316. S324: The developing bias is lowered by -20V, and the control is ended. S325: If the drum usage amount D when the power is ON is D> β, the process proceeds to S325 without changing the developing bias here. S326 to S332: Since they are the same as S316 to S321, the description is omitted. S333: The threshold value β is read by the control unit 65. S334: The control unit 65 compares the drum usage data D with the threshold value β. If “YES” is determined, S335
If the determination is "NO", the process returns to S327. S335: The developing bias is lowered by -20V, and S336
Proceed to. S336 to S341: Since they are the same as S316 to S321, the description is omitted. S342: The threshold value γ is read by the control unit 65. S343: The control unit 65 compares the drum usage data D with the threshold γ. If “YES” is determined, S344
If the determination is "NO", the process returns to S336. S344: The developing bias is lowered by -20V, and the control is terminated.

Thus, the control operation is completed (EN
D).

The transition of the line width obtained as a result of performing the above control is shown by a dashed line in FIG.
From this, it was found that the line width was changing in an appropriate range of 180 to 190 μm, and image stability was secured.

As described above, before the image forming standby, the initial charging and developing DC bias are changed according to the individual cartridges based on the photosensitive drum sensitivity information and the photosensitive drum use amount data. After that, by changing the bias to an appropriate bias according to the use in accordance with the value of the characteristic value, a stable line width can be obtained.

In this embodiment, two thresholds of the photosensitive drum use amount data are provided. However, a plurality of thresholds may be provided in consideration of the initial cartridge state and the configuration, and one threshold may be set for each step.
Although the EP bias has been lowered, this may be lowered or increased by a plurality of STEPs.

Although the developing voltage is changed as the process condition, the charging DC voltage may be changed simultaneously in order to secure the contrast between the charging potential and the developing potential. Needless to say, even if other process conditions, that is, charging and developing frequencies and exposure amounts are changed, the concept of the present invention is applied.

[0104]

As described above, the memory medium for the process cartridge, the process cartridge,
The electrophotographic image forming apparatus and the electrophotographic image forming system, wherein the main body of the image forming apparatus reads and writes contents stored in a memory medium provided in the process cartridge,
Means for statistically calculating the amount of use of the cartridge mounted on the image forming apparatus main body, and control means for changing image forming process conditions based on the used amount and information stored in the memory medium. Since the memory medium is configured to store information relating to parameter values for changing conditions unique to each process cartridge as information for changing image forming process conditions, (1) the information is stored in the memory. Since the timing for changing the process conditions can be set in accordance with the characteristics of each cartridge, it is possible to supply a stable image without variations in individual cartridges. (2) Since the memory further has information for identifying each individual cartridge, it is possible to reliably recognize that the cartridge has been changed on the main body side, so that the calculation of the used amount becomes accurate and the stability is improved. Image can be supplied. (3) When the process cartridge is mounted on the main body of the electrophotographic image forming apparatus, the memory of the process cartridge faces the antenna means provided on the main body of the electrophotographic image forming apparatus with a gap therebetween, and the memory and the antenna means By performing the information communication between and by using electromagnetic waves,
Since the timing for changing the process conditions can be set according to the characteristics of each cartridge stored in the memory, it is possible to supply a stable image while eliminating variations among the individual cartridges. Since a connector for connecting the main body is not required, the stability of information communication is increased, and a stable image can be supplied. And the like.

[Brief description of the drawings]

FIG. 1 is a sectional view of a process cartridge according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a process cartridge image forming apparatus according to a first embodiment of the present invention.

FIG. 3 is a graph showing the relationship between the total charging current amount and the photoconductor shaving amount according to the first embodiment of the present invention.

FIG. 4 is a graph showing the relationship between the number of printed sheets and the total amount of charging current in Example 1 according to the present invention.

FIG. 5 is a block diagram of a main body control unit information and a memory according to the first embodiment of the present invention.

FIG. 6 is a block diagram of a main body control unit and memory information according to the first embodiment of the present invention.

FIG. 7 is a flowchart of the first embodiment according to the present invention.

FIG. 8 is a diagram illustrating a relationship between drum usage amount data and total charging current amount according to the first embodiment of the present invention.

FIG. 9 is a block diagram of the main body control unit information and the memory in the case where there are a plurality of drum use amount calculation expression thresholds according to the first embodiment of the present invention.

FIG. 10 is a flowchart in the case where there are a plurality of drum usage amount calculation expression thresholds according to the first embodiment of the present invention.

FIG. 11 is a flowchart in the case where there are a plurality of drum use amount calculation expression thresholds according to the first embodiment of the present invention.

FIG. 12 is a relationship between the number of prints and the line width according to the second embodiment of the present invention.

FIG. 13 is a block diagram of main body control unit information and a memory according to the second embodiment of the present invention.

FIG. 14 is a block diagram of a main body control unit and memory information according to a second embodiment of the present invention.

FIG. 15 is a relationship between a developing DC bias and a line width according to a second embodiment of the present invention.

FIG. 16 is a flowchart in the case where drum sensitivity information is also used according to the second embodiment of the present invention.

FIG. 17 is a flowchart in the case where drum sensitivity information according to the second embodiment of the present invention is also used.

FIG. 18 is a flowchart when drum sensitivity information according to the second embodiment of the present invention is also used.

[Explanation of symbols]

 C Cartridge L Laser printer 1 Photoconductor drum 2 Contact charging roller 3 Laser unit 4 Toner container 5 Developing sleeve 6 Waste toner container 7 Developing blade 8 Stirrer 9 Transfer roller 10 Cleaning blade 12 Fixing unit 13 Main unit memory 14 Main unit transmitting unit 22, 62 Memory 23, 63 Cartridge-side transmission unit 24, 64 Main unit control unit 25, 65 Control unit 26, 66 Operation unit 27, 67 Photoreceptor rotation instruction unit 28, 68 Charging bias application time detecting unit 29 Charging current bias power supply 60 Drum sensitivity Detector 71 Development DC bias power supply

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H027 DA27 DA39 DA45 DE07 EA01 EC06 ED03 ED28 EE08 EE10 EJ05 FC03 HB15 HB18 ZA09 2H071 BA04 DA06 DA08 DA13 DA15 DA31 DA32

Claims (14)

[Claims] An electrophotographic photosensitive member and at least one of process means acting on the photosensitive member are integrally unitized and mounted on a process cartridge detachable from an image forming apparatus main body. A memory medium for a process cartridge that stores information and transmits the stored content to the image forming apparatus main body, wherein the image forming apparatus main body includes a unit that reads and writes the stored content of the memory medium, and the cartridge includes an image forming apparatus main body. Means for statistically calculating the amount used by being attached to the memory, and control means for changing image forming process conditions based on the amount used and information stored in the memory medium, wherein the memory medium In order to change the image forming process conditions, information on each process cartridge is provided. Memory medium for the process cartridge, wherein the information about the parameters values are stored for the condition change. 2. The process cartridge memory medium according to claim 1, wherein the parameter value for changing the condition specific to the process cartridge is information written according to the characteristics of the cartridge when the cartridge is manufactured. . 3. The parameter value for changing a condition specific to the process cartridge further includes information on characteristics of parts constituting each cartridge and / or threshold information for changing a process condition according to a used amount. 3. The memory medium for a process cartridge according to claim 2, wherein the information is information containing. 4. The memory medium for a process cartridge according to claim 1, wherein said memory medium for a process cartridge further has information for identifying each individual cartridge. 5. When the process cartridge is mounted in the main body of the image forming apparatus, the process cartridge is opposed to an antenna unit provided in the main body of the image forming apparatus with a gap therebetween, and communicates information with the antenna unit. 5. The process medium according to claim 1, wherein the step (c) is performed by using an electromagnetic wave. 6. A process cartridge in which at least one of an electrophotographic photosensitive member and process means acting on the photosensitive member is integrally unitized to be detachable from an image forming apparatus main body. In a process cartridge, comprising: a memory for storing; and a transmitting unit for transmitting the content stored in the memory to the image forming apparatus main body, wherein the image forming apparatus main body reads and writes the content stored in the memory of the process cartridge. Means, a means for statistically calculating the amount of use of the cartridge mounted on the image forming main body, and control means for changing image forming process conditions based on the used amount and information stored in the memory. In the memory, as information for changing the image forming process conditions, A process cartridge, characterized in that information about the parameter values for each of the process cartridges specific condition change is stored even without. 7. The process cartridge according to claim 6, wherein the parameter value for changing the condition specific to the process cartridge is information written to the memory according to the characteristics of the cartridge at the time of manufacturing the cartridge. Di. 8. The parameter value for changing a condition unique to the process cartridge may further include information on characteristics of parts constituting each cartridge and / or threshold information for changing a process condition according to a used amount. 8. The process cartridge according to claim 7, wherein the information includes information. 9. The memory according to claim 6, wherein the memory further has information for identifying each cartridge individual.
7 or 8 process cartridge. 10. When the process cartridge is mounted on the main body of the electrophotographic image forming apparatus, the transmitting means of the process cartridge has a gap with the antenna means provided on the main body of the electrophotographic image forming apparatus. 10. The process cartridge according to claim 6, wherein information communication between the memory means and the antenna means is performed by electromagnetic waves. 11. An electrophotographic image forming apparatus in which a process cartridge is detachable and which forms an image on a recording medium, comprising: (a) and (i) an electrophotographic photoconductor, and a process unit acting on the photoconductor. A process cartridge in which at least one unit is integrally unitized, (ii) a memory in which information on parameter values for at least changing conditions unique to each process cartridge is stored, and (iii) a storage content of the memory. Mounting means for removably mounting a process cartridge having cartridge transmitting means for transmitting to the image forming apparatus main body; and (b) the process when the process cartridge is mounted on the mounting means. An apparatus main body communication means for communicating stored contents through the cartridge transmission means of the cartridge If, based on (c) Information said process cartridge is statistically calculate the amount used in the image forming apparatus main body, and that the use amount and the apparatus main body transmission unit received,
An electrophotographic image forming apparatus, comprising: control means for changing image forming process conditions. 12. The apparatus main body transmitting means, when the process cartridge is mounted on the mounting means, faces the cartridge transmitting means of the process cartridge with a gap therebetween, and stores the contents stored in the memory. The electrophotographic image forming apparatus according to claim 11, further comprising an antenna unit that communicates with the cartridge transmitting unit. 13. An electrophotographic image forming system for forming an image on a recording medium using a process cartridge detachable from an electrophotographic image forming apparatus main body, comprising: (a) (i) an electrophotographic photosensitive member; A process cartridge in which at least one of the process means acting on the body is integrally unitized; (ii) at least information on the used amount of the process cartridge and parameter values for changing conditions unique to each process cartridge. And (iii) a cartridge transmitting means for transmitting the contents stored in the memory to the image forming apparatus main body; and (b) the process cartridge comprising the image forming apparatus. When attached to the main body, the cartridge included in the process cartridge is (C) statistically calculating an amount of the process cartridge used in the image forming apparatus main body, and transmitting the used amount and the apparatus main body. Based on the information received by the means,
An electrophotographic image forming system, comprising: control means for changing image forming process conditions. 14. The apparatus main body transmitting means, when the process cartridge is mounted on the image forming apparatus main body, faces the cartridge transmitting means of the process cartridge with a gap therebetween, and stores the memory in the memory. 14. The electrophotographic image forming system according to claim 13, further comprising antenna means for communicating contents with said cartridge transmitting means.