JP2019128588A - Image forming apparatus - Google Patents

Abstract

To maintain more appropriate control and provide good image formation when a process cartridge consists of two bodies: a drum unit and a developing unit.SOLUTION: An image carrier unit has a first storage member that holds first correction information according to information on the life of an image carrier. A developing unit has a second storage member that holds second correction information according to information on the life of the developing unit. Control means of an apparatus body acquires the first correction information stored in the first storage member and acquires the second correction information from the second storage member, corrects a charging bias by using the acquired first correction information and second correction information, and applies the corrected charging bias to a charging member.SELECTED DRAWING: Figure 6

Description

  The present invention relates to an electrophotographic image forming apparatus in which a detachable process cartridge has a two-body configuration of an image carrier unit and a developing unit. Examples of the image forming apparatus include a copying machine, a printer (laser beam printer, LED printer, etc.), a facsimile machine, a word processor, and a multifunction machine (multifunction printer) thereof.

In the image forming apparatus of the electrophotographic system, for the purpose of facilitating the replacement maintenance of the consumables such as the photosensitive member and the toner, the toner storage unit, the developing unit, the photosensitive member, the charging unit, and the cleaning unit There is known a system which is integrated as a process cartridge and configured to be attachable to and detachable from an image forming apparatus. There is also known a mode in which storage means (memory) is mounted on a process cartridge to manage cartridge information.
For example, in the image forming apparatus described in Patent Document 1, the storage means provided in the process cartridge contains, as information for changing the image forming process conditions, information on parameter values for changing the conditions unique to each process cartridge. Techniques for storing are disclosed.
Further, in the image forming apparatus described in Patent Document 2, for the purpose of the potential stability of the photosensitive drum (image carrier), the process cartridge is equipped with a non-volatile storage unit which can be read / written from the main body of the apparatus. . This storage means stores information such as charging characteristics, mechanical characteristic values, types and the like of the charging member, controls the condition of the charging bias applied to the charging member according to the information, and controls the charging of the photosensitive drum. Is disclosed.
Further, in Patent Document 3, control is performed so as to correct the conditions of the charger, the optical unit, the developing unit, or the transfer roller according to the storage means for storing the characteristics of the photosensitive drum and the characteristics of the photosensitive drum. And an image forming apparatus having the following control means.

JP 2001-117425 A JP-A-9-190140 Unexamined-Japanese-Patent No. 2000-47459

In recent years, with the diversification of user needs, there is a form of an image forming apparatus using an electrophotographic image forming process, a form of binary system divided into two for each function of the process cartridge. For example, a photosensitive unit (image supporting unit) having at least a photosensitive drum (image supporting unit), a developing unit, and a developing unit in which a toner container for storing the toner to be used is integrated are each an apparatus main body. There is a form that is made removable. For example, when each unit has a different life, each unit of such binary formation is used with an individual replacement life as compared with a conventional photosensitive unit and a process cartridge in which the development unit is integrated. There is a merit that can be done.
In the image forming apparatus of the two-body configuration having such merits, the following matters become important in order to maintain the potential stability of the photosensitive drum for a long time.
In general, even after the production of the image forming apparatus is finished, the consumables such as the photoconductor unit and the developing unit continue to be produced. At this time, when the specifications of the photosensitive drum, the charging roller, and the like are changed depending on the procurement condition of the material, the control information for performing appropriate charging control may be changed. For example, when the film thickness of the photosensitive drum to be used is changed, or when the hardness of the photosensitive drum is changed, the scraping speed is changed.
However, when the process cartridge is separated by the photosensitive unit and the developing unit, and units of different specifications are distributed to the market, the combination depends on which unit the user purchases and mounts on the image forming apparatus. Do. As described above, the specifications of the photosensitive drum and the charging roller can be changed due to various factors, and if the combination of units can not be predicted, the image forming apparatus can not execute appropriate control.
SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus capable of performing good image formation while maintaining more appropriate control when a process cartridge is dualized into an image carrier unit and a developing unit. .

In order to achieve the above object, the present invention provides:
An image carrier unit having at least an image carrier and a charging member, and a developing unit having at least a developer carrier are each independently detachable from the apparatus main body of the image forming apparatus,
The apparatus main body has a control means,
The image carrier unit has a first storage member for holding first correction information according to the life information of the image carrier,
The developing unit has a second storage member that holds second correction information according to the life information of the developing unit.
The control means acquires the first correction information stored in the first storage member and also acquires the second correction information from the second storage member, and the acquired first correction information and the second correction information To correct the charging bias and apply the corrected charging bias to the charging member.

  According to the present invention, when the process cartridge is divided into the image carrier unit and the developing unit, it is possible to perform better image formation while maintaining more appropriate control.

FIG. 1 is a schematic cross-sectional view of an image forming apparatus to which the present invention is applied. (A) is an external view of a drum cartridge, (B) is a schematic sectional drawing. FIG. 2 is a schematic view of a developing cartridge. (A) is a cross-sectional view of the developing cartridge, (B) is a schematic view of a developing blade. FIG. 2 is a control block diagram of the device of FIG. 1; 6 is a flowchart of correction control in Embodiment 1. 6 is a graph of a reference charging bias of Example 1. 6 is a graph of charging bias in which the first correction value of Example 1 is added. 8 is a graph of charging bias in which the second correction value of Example 1 is added. 8 is a graph of charging bias in which the second correction value of Example 2 is taken into consideration. 10 is a flowchart of correction control in Embodiment 3. FIG. 7 is a graph of charging bias when there is no correction in FIG. FIG. 8 is a graph of charging bias when the colors are different.

Hereinafter, the present invention will be described in detail based on the illustrated embodiments.
The image forming apparatus is an apparatus that forms an image on a recording medium using, for example, an electrophotographic image forming process. For example, an electrophotographic copying machine, an electrophotographic printer (for example, an LED printer, a laser beam printer, etc.), an electrophotographic facsimile machine, and the like are included.
Further, the cartridge refers to one that is detachable from the image forming apparatus main body. Among the cartridges, a cartridge in which the photosensitive drum and the process means acting on the photosensitive drum are integrated is called a drum cartridge (drum unit). Further, a unit in which the process means related to development is integrated is called a developing cartridge (developing unit).
Further, in the following embodiments, a full-color image forming apparatus in which four sets of drum cartridges and developing cartridges are detachable is illustrated. However, the number of drum cartridges and developing cartridges mounted in the image forming apparatus is not limited to this. Similarly, each component disclosed in the embodiments is not limited in terms of material, arrangement, dimensions, other numerical values, and the like, unless particularly limited. Further, unless otherwise specified, the upper side refers to the upper side in the direction of gravity when the image forming apparatus is installed.

First, the overall configuration of an electrophotographic image forming apparatus to which the present invention is applied will be described.
FIG. 1 is a schematic cross-sectional view of the image forming apparatus 200. As shown in FIG. 1, the image forming apparatus 200 includes a first image forming unit configured to form an image of each color of yellow (Y), magenta (M), cyan (C), and black (K) as a plurality of image forming units. It has second, third, and fourth image forming units SY, SM, SC, and SK. In the present embodiment, the first to fourth image forming units SY, SM, SC, and SK are arranged in a row substantially in the horizontal direction. In each of the image forming units SY, SM, SC, and SK, a drum cartridge 213 (213Y, 213M, 213C, 213K) and a developing cartridge 204 (204Y, 204M, 204C, 204K) are provided. In the present embodiment, the configurations and operations of the drum cartridge 213 (213Y, 213M, 213C, 213K) and the developing cartridge 204 (204Y, 204M, 204C, 204K) are substantially the same except that the color of the image to be formed is different. Is the same. Therefore, hereinafter, Y, M, C, and K will be omitted and they will be generally described, unless distinction is particularly required.

The drum cartridges 213 and the developing cartridges 204 of the image forming units SY, SM, SC, and SK are arranged side by side in a direction slightly inclined with respect to the horizontal direction. A unit (exposure device) 3 is disposed.
The developing cartridge 204 and the drum cartridge 213 are guided by guides such as a mounting guide and a positioning member (not shown) provided on the main body frame of the image forming apparatus main body 200A, and are independent from each other with respect to the image forming apparatus main body 200A. Is configured to be removable. Each color developer cartridge 204 contains toner of each color of yellow (Y), magenta (M), cyan (C), and black (K).
Around the photosensitive drum 1 of the drum cartridge 213, there are a charging roller 2 as a charging member as a process means acting on the photosensitive layer, a cleaning blade 6 as a cleaning means (cleaning device, cleaning member), and a developing cartridge. A developing roller 17 of 204 is disposed.

The charging roller 2 is a charging means (charging device, charging member) that uniformly charges the surface of the photosensitive drum 1, and the scanner unit (exposure device) 3 irradiates a laser based on image information to irradiate the photosensitive drum 1. Exposure means (exposure apparatus, exposure member) for forming an electrostatic image (electrostatic latent image) thereon.
A charging bias voltage is applied to the charging roller 2 from a charging bias voltage power source (not shown), and the photosensitive drum 1 is charged to a predetermined charging potential (-500 V in the present embodiment). The process of determining the charging bias will be described later. The charging bias in the present embodiment uses a direct current voltage (DC), but is not limited to this, and may be a so-called AC + DC superimposed voltage in which an alternating current voltage is superimposed on a direct current voltage.
The developing roller 17 of the developing cartridge 204 develops the electrostatic latent image formed on the photosensitive drum 1 by the scanner unit 3 with a developer. In the present embodiment, a non-magnetic one-component developer (hereinafter referred to as toner) is used as the developer, and a contact developing system in which a developing roller 17 as a developer carrying member is brought into contact with the photosensitive drum 1 is employed. .
Further, an intermediate transfer as an intermediate transfer body for transferring the toner image on the photosensitive drum 1 facing the four photosensitive drums 1 of the drum cartridges 213 of the image forming units SY, SM, SC, and SK. A belt 5 is arranged.
The intermediate transfer belt 5 abuts on the photosensitive drum 1 provided in each drum cartridge 213, and rotates (moves) in the direction of arrow B in FIG. The intermediate transfer belt 5 is stretched around a plurality of support members (a drive roller 51, a secondary transfer opposite roller 52, and a driven roller 53). On the inner circumferential surface side of the intermediate transfer belt 5, four primary transfer rollers 8 as primary transfer means are arranged in parallel so as to face the respective photosensitive drums 1. Further, on the outer peripheral surface side of the intermediate transfer belt 5, a secondary transfer roller 9 as a secondary transfer unit is disposed at a position facing the secondary transfer opposing roller 52.

Next, an image forming method will be described.
First, the surface of the photosensitive drum 1 is uniformly charged by applying a bias to the charging roller 2 from a charging bias power supply (not shown) in the main body of the image forming apparatus. Next, the surface of the charged photosensitive drum 1 is scanned and exposed by laser light corresponding to image information emitted from the scanner unit 3. As a result, an electrostatic latent image corresponding to the image information is formed on the photosensitive drum 1. The electrostatic latent image formed on the photosensitive drum 1 is developed as a toner image by the developing cartridge 204. The toner image formed on the photosensitive drum 1 is transferred (primary transfer) onto the intermediate transfer belt 5 by the action of the primary transfer roller 8.
For example, when forming a full color image, the above-described process is sequentially performed on the four drum cartridges 213 (213Y, 213M, 213C, 213K) and the developing cartridges 204 (204Y, 204M, 204C, 204K). Then, the toner images of the respective colors formed on the photosensitive drums 1 of the respective drum cartridges 213 are sequentially primary-transferred so as to be superimposed on the intermediate transfer belt 5. Thereafter, the recording material 12 is conveyed to the secondary transfer portion in synchronization with the movement of the intermediate transfer belt 5. Then, the four-color toner image on the intermediate transfer belt 5 is collectively transferred onto the recording material 12 conveyed to the secondary transfer portion formed by the intermediate transfer belt 5 and the secondary transfer roller 9.
The recording material 12 onto which the toner image has been transferred is conveyed to a fixing device 10 as a fixing unit. The toner image is fixed on the recording material 12 by applying heat and pressure to the recording material 12 in the fixing device 10. Further, the primary transfer residual toner remaining on the photosensitive drum 1 after the primary transfer process is removed by the cleaning blade 6 and collected as waste toner. Further, the secondary transfer residual toner remaining on the intermediate transfer belt 5 after the secondary transfer process is removed by the cleaning device 11 of the intermediate transfer belt 5. The image forming apparatus 200 can also form a single-color or multi-color image using a desired single or some (not all) image forming units.
Further, in the image forming apparatus 200, an environment sensor 210 is disposed as a means for measuring the temperature and humidity as the environment in the main body, and a control unit which calculates an absolute moisture amount as environmental information from the temperature and humidity 220 is arranged. The environment sensor 210 detects the present temperature and humidity, and obtains the absolute moisture content in the air from the temperature (° C.) and the relative humidity (% RH). Incidentally, the value of the absolute water content is 21.5 g at 30 ° C., 80% RH; 1.1 g at 15 ° C., 10% RH, and 11.8 g at 25 ° C., 60% RH at an atmospheric pressure of 760 mmHg. .
In the present embodiment, the environment sensor 210 is installed in the image forming apparatus 200 and the temperature and humidity in the image forming apparatus 200 are detected by way of example. The charging voltage control may be performed based on the temperature and humidity outside the image forming apparatus 200.

[Configuration of drum cartridge and developing cartridge]
Next, the drum cartridge 213 (213Y, 213M, 213C, 213K) and the developing cartridge 204 (204Y, 204M, 204C, 204K) shown in FIG. 1 will be described with reference to FIGS.
The drum cartridge 213Y, the drum cartridge 213M, the drum cartridge 213C, and the drum cartridge 213K have the same configuration and can be used regardless of the color. Also, the developing cartridge 204Y containing yellow toner, the developing cartridge 204M containing magenta toner, the developing cartridge 204C containing cyan toner, and the developing cartridge 204K containing black toner are the same except for the toner. It is a structure. Therefore, in the following description, the drum cartridges 213Y, 213M, 213C, and 213K are collectively referred to as the drum cartridge 213, and the developing cartridges 204Y, 204M, 204C, and 204K are collectively referred to as the developing cartridge 204. Similarly, each cartridge constituent member will be described generically.

Drum Cartridge FIG. 2 is an external perspective view of the drum cartridge 213. Here, as shown in FIG. 2, the rotational axis direction of the photosensitive drum 1 is in the Z direction (arrow Z1, arrow Z2), the horizontal direction in FIG. 1 is in the X direction (arrow X1, arrow X2), and the vertical direction in FIG. In the Y direction (arrows Y1 and Y2).
Drum unit bearing members 239R and 239L are attached to both sides of the cleaning frame 214, and respectively support the photosensitive drum unit 203. As a result, the photosensitive drum unit 203 is rotatably supported by the cleaning frame 214.
Further, the charging roller 2 and the cleaning blade 6 are attached to the cleaning frame 214, and these are arranged so as to come into contact with the surface of the photosensitive drum 1. Further, charging roller bearings 15L and 15R are attached to the cleaning frame 214. The charging roller bearings 15L and 15R are bearings for supporting the shaft of the charging roller 2.
Here, the charging roller bearings 15L and 15R are attached to be movable in the direction of arrow C shown in FIG. A rotating shaft 2 a of the charging roller 2 is rotatably attached to the charging roller bearing 15. The charging roller bearing 15 is urged toward the photosensitive drum 1 by a pressure spring 16 as urging means. As a result, the charging roller 2 comes into contact with the photosensitive drum 1 and rotates following the photosensitive drum 1.
The cleaning frame 214 is provided with a cleaning blade 6 as a cleaning unit that removes toner remaining on the surface of the photosensitive drum 1. The cleaning blade 6 is a blade-like rubber (elastic member) 6a that abuts on the photosensitive drum 1 and removes the toner on the photosensitive drum 1, and a supporting plate 6b that supports the rubber. In this embodiment, the support metal plate 6b is fixed and attached to the cleaning frame body 214 with screws.
As described above, the cleaning frame 214 has the opening 214b for collecting the transfer residual toner collected by the cleaning blade 6. The collected transfer residual toner is accommodated in a removed developer accommodating portion (hereinafter referred to as a waste toner accommodating portion) 214a through the opening 214b. The waste toner container 214 a and the cleaning blade 6 are integrated to form a drum cartridge 213. The opening 214b is provided with a blowout preventing sheet 26 that contacts the photosensitive drum 1 and seals the space between the photosensitive drum 1 and the opening 214b, and prevents toner leakage in the upper direction of the opening 214b.
Further, a non-volatile drum memory 150 for storing consumables information of the cleaning unit and control information used for potential control of the photosensitive drum is disposed in the cleaning frame 214, and the image forming apparatus side described later is provided. It can communicate with the control unit 220 of
The film thickness information of the drum cartridge 213 is the life information of the photosensitive drum 1, and is calculated by the control unit 220 of the image forming apparatus main body based on the rotation time of the photosensitive drum 1 and the usage environment information of the main body. The drum memory 150 is updated and stored. The replacement life is reached when the life film thickness held in the drum memory 150 is reached. Based on this film thickness information, unit life control and charging bias correction control described later are performed.
The lifetime information of the photosensitive drum 1 is not limited to the film thickness information, and may be the cumulative rotation number and cumulative rotation time of the photosensitive drum, the cumulative number of printed surfaces, the cumulative number of printed sheets, and the motor that drives the photosensitive drum. Indirect information such as the power on time may be used. In addition, the parameters include not only the number of rotations that have elapsed since the start of use but the remaining life such as the remaining number of rotations that can be reduced according to the use of the photosensitive drum and the rotation time.

FIG. 3 is an external perspective view of the developing cartridge 204.
The developing cartridge 204 has a developing device frame 218 supporting various elements. The developing cartridge 204 is provided with a developing roller 17 as a developer bearing member that rotates in the direction of arrow D (counterclockwise direction) shown in FIG. 4A in contact with the photosensitive drum 1. The developing roller 17 is rotatably supported on the developing frame 218 via developing bearings 219 (219R, 219L) at both ends in the longitudinal direction (rotation axis direction). Here, the developing bearings 219 (219R, 219L) are respectively attached to both side portions of the developing device frame 218.
Further, as shown in FIG. 4A, the developing cartridge 204 has a developer storage chamber (hereinafter, toner storage chamber) 218a and a developing chamber 218b in which the developing roller 17 is disposed.
In the developing chamber 218b, regulation of the developer for regulating the toner layer (developer layer) of the toner supply roller 20 and the developing roller 17 as a developer supply member which contacts the developing roller 17 and rotates in the direction of arrow E A developing blade 21 as a member is disposed. The developing blade 21 is fixed to and integrated with the fixing member 22 by welding or the like.
Further, in the toner storage chamber 218a of the developing device frame 218, a stirring member 23 for stirring the stored toner and for conveying the toner to the toner supply roller 20 is provided.
Further, a development memory 151 as a nonvolatile first storage means for storing consumable information on the development cartridge and control information for image optimization is disposed in the toner storage chamber 218a of the development frame 218. And can communicate with the control unit 220 on the image forming apparatus side.
Further, the life information of the developing cartridge 204 (hereinafter referred to as developing life) is calculated by the control unit 220 of the image forming apparatus main body based on the rotation time of the developing roller 17 and is sequentially updated and stored in the developing memory 151. The replacement life is reached when the number of rotations held in the development memory 151 is reached. Based on the development life information, correction control of the charging bias described later is performed.
The life information of the developing cartridge 204 may be the cumulative rotation speed and cumulative rotation time of the developing roller 17 itself, or indirectly such as the cumulative number of printed surfaces, the cumulative number of printed sheets, and the energization time of the motor that drives the developing roller 17. It may be information. In addition, the parameters include not only the number of rotations that have elapsed since the start of use but the remaining life such as the remaining number of rotations that can be reduced according to the use of the photosensitive drum and the rotation time.

[Control block diagram]
A control block diagram of the image forming apparatus 200 will be described.
The main body controller 201 inputs and outputs information with the control unit 220 (central processing unit) as a control means which is a central element that performs arithmetic processing, a ROM as a storage means, a main memory 221 such as a RAM, and peripheral devices. It has an input / output interface 222 and the like. The RAM of the main body memory 221 stores the detection result of the environment sensor 210, the calculation result, and the like, and the ROM stores a control program, a data table obtained in advance such as a charge application table storage unit described later, and the like. The control unit 220 is a control unit that generally controls the operation of the image forming apparatus 200, and each control target in the image forming apparatus 200 is connected via an input / output I / F 222. The control unit 220 controls transmission / reception of various electrical information signals, driving timing, and the like, and controls processing of a flowchart described later.
The motor drive unit 511 refers to various motors, and is a power source for rotating and driving a polygon scanner, the photosensitive drum 1, the developing roller 17 and the like, and operates based on a control signal from the control unit 220. The high voltage power supply 512 is a power supply that applies a high voltage to the photosensitive drum 1, the charging roller 2, the developing roller 17, the primary transfer roller 8, the secondary transfer roller 9, the fixing device 10, and the like.
The drum memory 150 of the drum cartridge 213 and the development memory 151 of the development cartridge 204 are connected to the main body controller 201 via the memory communication unit 500.

Example 1
Hereinafter, the correction control of the charging bias of the image forming apparatus according to the first embodiment of the present invention will be described.
The factors that disturb the stability of the charging potential of the photosensitive drum 1 are largely the two points of the potential change due to the contamination of the charging roller 2 and the potential change due to the scraping of the photosensitive drum 1 due to the discharge. It is known that these factors are easily affected by the surface characteristics of the charging roller 2 used, the hardness of the photosensitive drum 1, and the durability deterioration of the developing toner used. In addition, the temperature and humidity of the environment in which the image forming apparatus is used are also strongly affected.
In the first embodiment, correction information of the charging bias applied to the charging roller 2 is held in each of the developing cartridge 204 and the drum cartridge 213. The developing cartridge 204 is characterized in that the combination of the drum cartridge 213 holds information optimized in consideration of the difference in contamination due to the developing cartridge 204.
This is effective when the combination of the drum cartridge 213 is limited to about two to three. Further, even when the life of the developing cartridge 204 is shorter than that of the drum cartridge 213 and the replacement frequency is high, the accuracy is improved, which is effective.
In the control block diagram shown in FIG.
In the main body memory 221 of the apparatus main body 200A, information on the reference charging bias (reference information) to be applied to the charging roller 2 corresponding to the life information of the photosensitive drum 1 is held in advance.
The drum memory (first storage member) 150 of the drum cartridge (image carrier unit) 213 holds in advance first correction information corresponding to film thickness information which is life information of the photosensitive drum 1.
The development memory (second storage member) 151 provided in the developing cartridge (developing unit) 204 holds second correction information corresponding to developing life information, which is life information of the developing cartridge 204.
The control unit 220 of the main body controller 201 calculates the film thickness information of the photosensitive drum 1 based on the rotation time of the photosensitive drum 1 and the like, and sequentially updates it. The first correction value (β) corresponding to the film thickness information is acquired. The control unit 220 also calculates the development life of the development cartridge 204 based on the rotation time of the development roller 17 and the like, and sequentially updates the development life from the second correction information stored in the development memory 151. The corresponding second correction value (γ) is obtained. Then, using the acquired first correction value (β) and second correction value (γ), the reference charging bias (α) is corrected to be a charging application bias to be applied to the charging roller 2.
In the first embodiment, a plurality of types of reference charging bias, first correction information, and second correction information are set according to the absolute water content, which is environmental information.

Correction control of charging bias
Hereinafter, the flow of the charging bias correction control in the first embodiment will be described in detail with reference to the flowchart shown in FIG.
In the following description, the operation of 1st (Y station) in the image forming apparatus 200 will be described. Since the operations from 2st to 4st are also controlled by the same flow, detailed description is omitted. Here, 1st to 4st are stations of 1st yellow, 2st magenta, 3st cyan, and 4st black, respectively, and hereinafter referred to simply as 1st, 2st, 3st, 4st.
(S101)
In S101, the main body power supply of the image forming apparatus 200 is turned on. Thus, the control unit 220 starts charging bias control based on the control program stored in the main body memory 221.
(S102)
In step S102, the control unit 220 checks the environment sensor 210, acquires temperature / humidity information in the image forming apparatus 200 detected by the environment sensor 210, and obtains the absolute water content in air as environmental data (hereinafter referred to as the water content). Calculate In addition, when an output value (for example, a resistance value) corresponding to the amount of moisture in the air can be directly obtained from the environment sensor 210, the calculation of the absolute amount of moisture may be omitted. The same applies to the other tables.
(S103)
In S <b> 103, the control unit 220 reads the reference charging bias information (αy) corresponding to the calculated water content from a table as shown in the base table 16. Details of Table 16 will be described later. Table 16 is stored in advance in the memory 221 of the main body controller 201, and each table described later is also stored in advance in any of the memory 221, the drum memory 150, and the development memory 151. .
(S104)
In S <b> 104, the control unit 220 confirms the drum memory 150 by communicating with the drum memory 150 of the drum cartridge 213.
(S105)
In S <b> 105, the control unit 220 confirms the development memory 151 by communicating with the development memory 151 of the development cartridge 204.
Hereinafter, the control differs depending on whether or not the drum memory 150 and the development memory 151 are recognized. The classification of presence / absence of recognition is divided into the following four cases (1A to 1D).
1A: When both the drum memory 150 of the drum cartridge 213 and the developing memory 151 of the developing cartridge 204 are recognized 1B: When only the drum cartridge 213 is recognized (mounted) the drum memory 150 1C: Only the developing cartridge 204, developing memory When 151 is recognized (mounted) 1D: When neither the drum memory 150 of the drum cartridge 213 nor the developing memory 151 of the developing cartridge 204 is recognized (mounted)

<In the case of 1A>
In this case, the process proceeds to S106, S107, S108, S109, S110, and S115.
When the drum memory is recognized in S106, the process proceeds to S107, and a correction value βy according to the absolute moisture amount and the use condition of the drum cartridge is calculated from Table 2.
That is, in S107, the control unit 220 acquires the film thickness information of the photosensitive drum from the drum memory 150 of the drum cartridge 213. That is, film thickness information based on the usage history information is held in the drum memory 150, and the control unit 220 calculates the film thickness information from the rotation time of the photosensitive drum 1 and updates it sequentially. Then, referring to the correction table of Table 2 as the first correction information held in the drum memory 150 in advance, the first moisture value that matches the absolute moisture amount calculated in S102 and the acquired drum film thickness of the photosensitive drum 1 is obtained. The correction value (βy) is calculated. Details of Table 2 will be described later. In S107, since the control unit 220 reads the film thickness information from the drum memory 150, the reference charging bias αy acquired based on the table in Table 16 in S102 is reacquired based on the table in Table 1.
In the first embodiment, all the held values in the correction table of Table 2 are set to 0. That is, in the first embodiment, it is assumed that the charging bias is not corrected according to the unique information of the drum cartridge 213 because the influence of the assembly variation at the time of manufacture is small.
Note that the drum memory 150 of the drum cartridge 213 does not have color information, and the color is determined when the station used is mounted. In the first embodiment, it is stored in advance in the main body controller 201 so that 1st is recognized as yellow, 2st is magenta, 3st is cyan, and 4st is black. Thus, the drum cartridge 213 can be used at any station because it is designed to be detachable from any station. The order of the colors of the stations used and the toner used is not limited to this, and color information may be determined freely for each station.
(S108, S109)
When the correction value βy is calculated, the process proceeds to S108, the tag of the development memory is checked, and if there is a development memory, the process proceeds to S109. A second correction value (γy) is calculated.
That is, the control unit 220 obtains the development life of the development cartridge 204 from the development memory 151 of the development cartridge 204, and the control unit 220 calculates the development life from the rotation time of the development roller 17 and updates it sequentially. Then, with reference to the correction table of Table 3 stored in advance in the development memory 151, a yellow table is selected from among a plurality of types of correction tables. Furthermore, a second correction value (γy) that matches the moisture amount calculated in S102, the acquired development life, and the drum film thickness is calculated. Details of Table 3 will be described later.
(S110)
In S110, the reference charging bias αy calculated in S103, the first correction value βy calculated from Table 2 based on the usage information of the photosensitive drum 1 in S107, and the usage information of the developing cartridge 204 are calculated in S109. Using the second correction value γy, the charging application bias (Vpy) to be actually applied is calculated from the following calculation formula.
Charge application bias (Vpy) = αy + βy + γy (1)
(S115)
In S115, the control unit 220 controls the high-voltage power supply 512 to apply the charging bias to the charging roller 2 based on the calculated charging application bias Vpy.

<In the case of 1B>
(When only the drum memory of the drum cartridge is recognized (mounted))
In this case, the process proceeds to S106, S107, S108, S111, and S115.
That is, S106 and S107 are the same as in the case of 1A, the first correction value βy is calculated, and in S108, the information of the developing memory 151 of the developing cartridge 204 can not be obtained, so the process proceeds to step 111.
In this case, in the calculation formula (1), the second correction value (γy) is indeterminate. For this reason, the charging application bias to be actually applied is determined by the following calculation formula.
Vpy = αy + βy (2)
In the case of the first embodiment, since all the holding values of the correction table described in Table 2 are set to 0, Vpy = αy after all.
When the calculated charging application bias Vpy is determined, the process proceeds to S115, where the control unit 220 controls the high voltage power supply 512 to apply the charging bias to the charging roller 2. That is, the charging bias is applied to the charging roller 2 with the charging bias Vpy as αy.

<In the case of 1C>
(Only when developing cartridge is recognized (mounted) developing memory)
In this case, the process proceeds to S106, S112, S113, and S115.
That is, in S106, since the information of the drum memory 150 of the drum cartridge 213 cannot be obtained, the process proceeds to S112. If the development memory is recognized, the process proceeds to S113. In this case, βy is indefinite in the calculation formula (1).
In S113, since the use information of the drum cartridge in Table 3 can not be obtained, the correction based on only the use situation of the developing cartridge 204 is performed. In this case, the life (film thickness) of the photosensitive drum is controlled as an initial value.
That is, from Table 3, the second correction value γ′y corresponding to the life information of the developing cartridge 204 is calculated by assuming that the life of the drum cartridge is an initial value (for example, drum initial film thickness 25 μm), and the charging application bias to be actually applied is calculated. Is determined by the following formula.
Vpy = αy + γ'y (3)

<In the case of 1D>
(If neither the drum memory of the drum cartridge nor the developing memory of the developing cartridge can be recognized (mounted))
In this case, the process proceeds to S106, S112, S114, and S115.
That is, in the step of recognition of the drum memory 150 (S106) and the step of recognition of the development memory 151 (S112), both are (absent) and the process proceeds to S114.
In this case, since neither the drum memory 150 nor the development memory 151 can be recognized, all of βy and γy in the calculation formula (1) become undefined.
Therefore, the charging application bias Vpy is controlled by the bias described in Table 16 preset in the main body controller 201.
As a result, a bias is applied to the charging roller 2 at the charging bias Vpy calculated by the main body controller 201.
Table 16 shows a table holding the reference charging bias when the memory tag is indeterminate. The operation is controlled commonly to 1st to 4st. Since the life of the photosensitive drum 1 is indeterminate, the charging bias is set to enable image formation regardless of the drum film thickness. FIG. 12 shows the corresponding graph.

As described above, the image forming operation can be performed even when the drum memory 150 and the development memory 151 are not recognized.
Next, Table 1, Table 2, and Table 3 used in the above-described flowchart will be described in detail.

Table 1 is a reference charging bias table that holds data on the reference charging bias (charging bias reference information) based on the drum film thickness that is life information of the photosensitive drum 1 and the moisture amount that is environment information. Four tables (1st to 4st) for each color are held in the main body memory 221 of the main body controller 201. The description of the flowchart is an example of 1st (Y station).
The horizontal axis of each table is the drum film thickness, and holds three levels of 30 μm, 20 μm, and 10 μm, respectively. The film thickness between the three levels is calculated and calculated by the control unit 220 of the main body controller 201 by linear interpolation based on the charging table.
The vertical axis of each table is the amount of water that is environmental information calculated by the control unit 220 from the temperature and humidity detected by the environmental sensor 210, and is 30 ° C. and 80% RH at high temperature and high humidity (HH). Three levels of 21.5 g, 1.1 g at 15 ° C. and 10% RH at low temperature and low humidity (LL), and 11.8 g at 25 ° C. and 60% RH at room temperature and normal humidity (NN) are maintained. Based on the measured amount of water and the amount of water calculated from the humidity, the amounts of water are linearly interpolated and calculated. When an output value (for example, resistance value) corresponding to the amount of moisture in the air can be directly obtained from the environment sensor 210, the detected value may be used directly.
In the first embodiment, the drum film thickness and the moisture amount are maintained at three levels, but the present invention is not limited to this and can be increased or decreased according to the capacity of the memory tag.
In the first embodiment, the drum film thickness and water content held in the table are linearly interpolated in consideration of errors and calculation amounts, but may be nonlinear interpolation.
A graph 1 shown in FIG. 7 shows the relationship between the drum film thickness, the charging bias, and the temperature and humidity shown in Table 1.
In addition, the table of this Table 1 is obtained from the evaluation result by this inventor, and, in the case of the use film thickness (30 micrometers), it sets as follows, for example.
HH (high temperature and high humidity): Temperature 30 ° C, humidity 80% Applied charging voltage value: -1050V
NN (normal temperature and normal humidity): temperature 25 ° C., humidity 60% Output transfer current value: −1100V
LL (low temperature and low humidity): temperature 10 ° C., humidity 15% output transfer current value: −1150V
This phenomenon can be explained by Paschen's law. That is, the relative dielectric constant of the photosensitive layer changes due to the influence of the temperature and humidity around the photosensitive member, and the discharge start voltage changes.

Table 2 is a correction table in which first correction information based on the drum film thickness, which is life information of the photosensitive drum 1 held in the drum memory 150 of the drum cartridge 213, and the moisture amount, which is environment information, is held. .
The horizontal axis of the correction table is the drum film thickness (photosensitive drum life information), and holds three levels of 30 μm, 20 μm, and 10 μm, respectively. The film thickness between the three levels is calculated and calculated by the control unit 220 of the main body controller 201 by linear interpolation based on the charging table.
The vertical axis of the correction table is the amount of water that is the environmental information calculated by the control unit 220 from the temperature and humidity detected by the environmental sensor 210. As in Table 1, the vertical axis is 21.21 at high temperature and high humidity (HH). Three levels of 5 g, 1.1 g at low temperature and low humidity (LL), and 11.8 g at room temperature and normal humidity (NN) are maintained. Based on the amount of water calculated from the detected temperature and humidity, the amount of water is linearly interpolated and calculated.
In the first embodiment, all the held values in the correction table of Table 2 are set to 0. That is, in the first embodiment, it is assumed that the charging bias is not corrected according to the unique information of the drum cartridge 213 because the influence of the assembly variation at the time of manufacture is small.
In the first embodiment, the values held in the correction table of Table 2 are all set to 0, but Table 2 is a correction table based on information unique to the drum cartridge 213, and correction information based on the unique information. Can be held.
FIG. 8 is a graph in which the first correction value βy is added to the charging reference bias value αy of the graph 1, and the first correction value βy is 0. Therefore, the graph 2 is the same as the graph 1. FIG. 13 is a graph of the charging reference bias when the colors are different.

Table 3 shows the holding values of the correction tables of the plurality of types of second correction information held in the developing memories 151 of the four-color developing cartridges 204.
These correction tables are tables for predicting contamination due to the drum film thickness of the photosensitive drum 1 of the drum cartridge 213 and the developing life of the developing cartridge 204. That is, since the contamination of the charging roller 2 changes depending on the toner used, the electrostatic capacity changes and the discharge start voltage changes. In consideration of this phenomenon, correction values for correcting the potential drop are held in the correction table of the drum cartridge 213 of each color so as to obtain a desired dark area potential.
The correction table has three tables with three levels of moisture for each color, and has twelve tables for four colors. The water content is three levels of 21.5 g at high temperature and high humidity (HH), 1.1 g at low temperature and low humidity (LL), and 11.8 g at normal temperature and normal humidity (NN).
The horizontal axis of the correction table represents the drum film thickness that is the drum life, and holds three levels of 30 μm, 20 μm, and 10 μm, respectively. When the film thickness is between three levels, it is calculated and calculated by the control unit 220 of the main body controller 201 by linear interpolation as in the charging table.
The vertical axis of the correction table is the development life and is divided into three levels of 100% to 90%, 90% to 40%, and 40% to 0%. The vertical axis of this correction table may be replaced with the driving amount (rotation speed or driving time) instead of the remaining development life.

Graphs 3-1 and 3-2 shown in FIG. 9 show the relationship between the drum film thickness and the charging bias and the temperature and humidity corresponding to Table 3.
Graphs 3-1 and 3-2 are graphs for explaining the correction table in Table 3, and correspond to three tables for each yellow water content in Table 3.
The life of the photosensitive drum 1 is longer than the life of the developing cartridge 204, and the developing cartridge 204 is replaced during the life of the photosensitive drum 1. The correction table of Table 3 constituting the second correction information is preset according to the drum film thickness which is the drum life and the development life (life information) of each of the plurality of developing cartridges 204 to be replaced. In this example, two developer cartridges 204 are used.
The graph 3-1 represents the transition of the charging bias when both the drum cartridge 213 and the developing cartridge 204 are used from new.
That is, it is a graph of the charging bias control when the yellow developing cartridge 204 is passed from the drum film thickness 25 μm to the drum film thickness 20 μm.
The relationship between the development life and the drum film thickness is that the development life decreases from 100% to 0% when the developing cartridge 204 is new and two sheets of A4 paper are intermittently passed, and the replacement life is reached. At this time, the drum film thickness of the drum cartridge 213 is set to decrease from 25 μm to 20 μm.
Similarly, graph 3-2 is a graph of charge bias control when passing a sheet so as to use up the development life up to a drum film thickness of 15 μm by replacing with a new developing cartridge 204 when the drum film thickness of the drum cartridge 213 is 20 μm. is there.
In any of the graphs 3-1 and 3-2, correction values are added at 90% and 40% shown in the yellow correction table of Table 3, and a state where the correction is made to the proper charging bias Vpy is shown.
That is, based on the moisture information detected by the environment sensor 210 and the second correction value (γy) corresponding to the development life and the drum film thickness, as shown in graphs 3-1 and 3-2, the charge application bias (Vpy) Be controlled.
As described above, the first correction value βy according to the moisture content in the air (temperature and humidity) at the time of use and the drum film thickness of the drum cartridge 213, the moisture content in the air at the time of use (temperature and humidity) and the development By combining with the second correction value γy according to the development life of the cartridge 204, an appropriate charging bias Vpy can be obtained. By controlling in this manner, the surface potential of the photosensitive drum can be stably maintained for a long time.

[Other embodiments]
Next, another embodiment of the present invention will be described. In the following description, only differences from the first embodiment will be described, and the description of the same configuration and operation will be omitted.
Example 2
First, a second embodiment of the present invention will be described.
In the correction control of the charging bias in the second embodiment, four types of cartridges having different characteristics with regard to the drum cartridge 213 are considered. In particular, variation in characteristics due to the combination of the photosensitive drum 1 and the charging roller 2 which are key parts of the drum cartridge 213 is taken into consideration.
This is suitable for holding unique information at the time of manufacturing the drum cartridge. By holding the first correction value considering the unique variation at the time of manufacturing the drum cartridge, the correction accuracy can be improved compared to the first embodiment. It is a higher one.
That is, the drum memory 150 of the drum cartridge 213 has a correction table unique to the drum cartridge. This is a case where the correction table needs to be changed at the time of manufacturing the drum cartridge 213, and the drum memory 150 holds a correction value in consideration of the characteristic variation of the drum cartridge 213 unique at the time of manufacturing.
The information held by the drum memory 150 is based on data measured by various measuring devices at the time of manufacturing the drum cartridge. Thereby, the correction accuracy by the image forming apparatus 200 can be further improved. On the other hand, when the variation at the time of manufacture is limited and the influence on the correction is not large, the value held by the drum memory 150 may be set to zero. Alternatively, the drum memory 150 may not store variation information at the time of manufacture, and in that case, the main body controller 201 may read a default correction value of, for example, zero from the memory and use it.
As the specific information, in the second embodiment, a combination of the photosensitive drum 1 and the charging roller 2 is assumed. Table 4 is a table based on drum film thickness and drum cartridge specific information. The combination of the photosensitive drum 1 and the charging roller 2 changes the environmental characteristics and changes the necessary charging bias. This is because the capacitance formed by the photosensitive drum 1 and the charging roller 2 changes, and the capacitance becomes unique for each combination of the photosensitive drum 1 and the charging roller 2.
Further, since the scraping speed changes depending on the hardness of the charging roller 2 and the photosensitive drum 1, the reduction amount of the drum film thickness is different even at the same rotation number. Due to this, the necessary charging bias changes.
Therefore, the drum memory 150 corresponding to the combinations 1-1 to 1-4 is disposed on the drum cartridge 213.
For example, when the photosensitive drum of the combination name 1-1 is manufactured, a table of the combination name 1-1 described in Table 5 is held in the drum memory 150. Similarly, when the drum cartridge of combination name 1-2 is manufactured, the table of combination 1-2 described in Table 5 is held in the drum memory 150. If identification at the time of manufacture is difficult, the drum memory 150 may hold information of all the combination information 1-1 to 1-4 in advance.
The combination of the developing cartridge 204 and the drum cartridge 213 held in the developing memory 151 holds all the tables of the combinations 1-1 to 1-4, and is held in the drum memory 150 of the drum cartridge 213. Refer to the table from the identification information.

The combinations in Table 4 will be described below.
[About Photosensitive Drum 1]
The following two types of photosensitive drums 1 are used.
A type: drum initial film thickness 25 μm, scraping speed 0.8 μm / 1000 sheets B type: drum initial film thickness 22 μm, scraping speed 0.15 μm / 1000 sheets In the first and second embodiments, the photosensitive material at the center of the image forming process In the body drum 1, an undercoat layer is formed on a support, a charge generation layer is formed on the undercoat layer, and a charge transport layer is formed on the charge generation layer. The charge transport layer preferably contains a charge transport material and a resin, such as a polycyclic aromatic compound, a heterocyclic compound, a hydrazone compound, a styryl compound, an enamine compound, a benzidine compound, a triarylamine compound, Examples thereof include a resin having a group derived from these substances.
Examples of the resin include polyester resin, polycarbonate resin, acrylic resin, and polystyrene resin. Among these, polycarbonate resin and polyester resin are preferable. As the polyester resin, a polyarylate resin is particularly preferable.
The content ratio (mass ratio) between the charge transport material and the resin is preferably 4:10 to 20:10, and more preferably 5:10 to 12:10.
The charge transport layer may also contain additives such as an antioxidant, an ultraviolet light absorber, a plasticizer, a leveling agent, a slipperiness imparting agent, and an abrasion resistance improver. Specifically, hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, silicone oil, fluorine resin particles, polystyrene resin particles, polyethylene resin particles, silica particles, alumina particles, boron nitride particles Etc.
The average film thickness of the charge transport layer is preferably 5 μm or more and 50 μm or less, more preferably 8 μm or more and 40 μm or less, and particularly preferably 10 μm or more and 30 μm or less. The photosensitive drum A for carrying out the present invention was 25 μm, and the photosensitive drum B was 22 μm.
The charge transport layer can be formed by preparing a coating solution for a charge transport layer containing the above-mentioned materials and solvent, forming this coating film, and drying it. Examples of the solvent used for the coating solution include alcohol solvents, ketone solvents, ether solvents, ester solvents, and aromatic hydrocarbon solvents. Among these solvents, ether solvents or aromatic hydrocarbon solvents are preferable.

  The photosensitive drum used in Examples 1 and 2 was a laminated type photosensitive member having a charge generation layer and a charge transport layer, but a single layer type photosensitive material containing both a charge generation material and a charge transport material. You may use the body. The single-layer type photoreceptor can be formed by preparing a coating solution for a photosensitive layer containing a charge generating substance, a charge transporting substance, a resin and a solvent, forming this coating film, and drying it. The charge generating substance, charge transporting substance, and resin are the same as those exemplified for the material in the multilayer photoreceptor. Depending on the binder added to the charge transport layer, the hardness of the drum can be changed, and the scraping speed per unit rotation speed can be changed accordingly.

[About charging roller 2]
The following two types of charging rollers 2 are used.
A-type charging roller: surface roughness Rz 20 to 30 μm
B-type charging roller: surface roughness Rz 10 to 20 μm
The fact that the charging roller 2 charges the photosensitive drum 1 means that the charging roller 2 discharges to the surface of the photosensitive drum 1 and the charge moves. A discharge occurs when the potential difference between the surface of the charging roller 2 and the surface of the photosensitive drum 1 exceeds the Paschen discharge limit Vpa, and the charge ΔQ moves to the surface of the photosensitive drum 1 (Paschen's law). The sum of the ΔQ is the charge Q accumulated in the photosensitive drum 1. ΔQ is expressed by the relational expression of the gap (di) between the charging roller 2 and the photosensitive drum 1 and the respective dielectric constants (εi). The dielectric constant changes with the hardness and resistance of the charging roller 2 and the surface roughness.
Generally, at least a rubber component and a conductive agent must be contained as components constituting the charging roller 2. Examples of rubber components include epichlorohydrin rubber, EPM (ethylene propylene rubber), EPDM (ethylene propylene diene rubber), norbornene rubber, NBR (nitrile rubber), chloroprene rubber, natural rubber (NR), isoprene rubber, and polybutadiene rubber (BR). ), Styrene-butadiene rubber (SBR), chlorosulfonated polyethylene, urethane rubber, SBS (styrene-butadiene-styrene-block copolymer), SEBS (styrene-ethylenebutylene-styrene-block copolymer) and other styrenic block copolymers and silicone Rubber etc. are mentioned.
Further, as a conductive agent, for example, perchlorate such as LiClO ₄ or NaClO ₄ , ion conductive agent such as quaternary ammonium salt, metal powder or fiber such as aluminum, palladium, iron, copper, silver, carbon, carbon Black, metal powder, metal oxide such as titanium oxide, tin oxide, zinc oxide etc., metal compound powder such as copper sulfide, zinc sulfide etc. or suitable particles tin oxide, antimony oxide, indium oxide, molybdenum oxide, zinc , Aluminum, gold, silver, copper, chromium, cobalt, iron, lead, platinum, rhodium electrolytically deposited, spray coated, powder mixed by shaking, acetylene black, ketjen black, PAN (polyacrylonitrile) Carbon, carbon powder such as pitch carbon, carbon coated silica, carbon coated magnetite, carbon coated titanium oxide, Electronic conductive agents such as conductive whiskers such as carbon-coated barium sulfate, carbon whisker, graphite whisker, titanium carbide whisker, conductive potassium titanate whisker, conductive barium titanate whisker, conductive titanium oxide whisker, and conductive zinc oxide whisker Can be mentioned.

These rubber components and conductive agents may be used in any combination, but epichlorohydrin rubber and ionic conductive agent are particularly preferred for the purpose of reducing the unevenness of the electrical resistivity of the base layer.
In this embodiment, the charging roller manufactured using the same material contains a surface layer binder and fine particles as a surface roughening agent. The fine particles have a volume average particle size of 10 to 50 μm, preferably 20 to 40 μm, and may be either spherical particles or irregularly shaped particles. Furthermore, the amount of fine particles with respect to the surface layer binder is 10 to 100 wt%, and only the surface roughness is changed by changing the amount of particles to be added. The ten-point average roughness of the surface of the charging roller 2 is Rzjis = 15 to 50 (μm), preferably Rzjis = 10 to 30 (μm). In this embodiment, the A-type charging roller 2 has a roughness of 25 μm, and the B-type charging roller 2 has a roughness of 10 μm.
The Rzjis measurements were based on JIS-B0601-2001, and a surface roughness measuring device Surfcoder SE3500 manufactured by Kosaka Laboratory Ltd. was used. In the longitudinal direction, measurement was performed under the conditions of a measurement length of 8.0 mm, a cutoff value of 0.8 mm, and a measurement speed of 0.3 mm / sec.
In this embodiment, the correction amount for correcting the difference in dielectric constant caused by the difference in the film thickness of the photosensitive drum 1 and the surface roughness of the charging roller 2 is provided. However, the present invention is not limited to this. It is also suitable as a correction table based on other parameters.
For example, in the case of the sensitivity of the photosensitive drum 1, the hardness, the deflection, and the charging roller 2, the environmental characteristics of resistance, the environmental characteristics of hardness, and the like.

[Control flow]
Next, the flow up to the determination of the charging bias in the second embodiment will be described.
The control flow is the same from (S101) to (S106) described in the first embodiment, and in S107, the control unit 220 identifies which drum cartridge of the combination 1-1 to 1-4 it is, for example, If the combination is a drum cartridge of 1-1, the correction table described in Table 5 is referred to instead of Table 2, and if the combination is a drum cartridge of 1-2, the table described in 1-2 of Table 5 Is referred to, and the first correction value βy is obtained.

On the other hand, in S108 and S109, the control unit 220 acquires usage information (lifetime information) from the development memory 151 of the development cartridge 204, and the charging bias based on the temperature and humidity held in the development memory 151 and the usage information of the development cartridge 204 is obtained. The second correction value (second correction information) γy is obtained from the correction table shown in Table 6.
In step (S110), the charging bias Vpy is calculated based on the calculation formula (1).

Table 6 shows an example of a table held in each developing memory 151 of the four-color developing cartridge 204.
That is, it is a stain prediction table based on the film thickness information of the drum cartridge 213 and the developing life of the developing cartridge 204, and the holding value is the second correction value γy of the charging bias in the above calculation formula (2). The second embodiment has a second correction value table corresponding to the development life for each type of each drum cartridge 213.

FIGS. 10A and 10B show graphs 6-1 and 6-2 for explaining the holding values of the correction table in Table 6, respectively.
The graph 6-1 corresponds to the table in Table 6. That is, Table 6 corresponds to the station of yellow, the combination of drum cartridge (1-1), and the moisture amount LL, and the same table also applies to (NN) and (HH) of other moisture amounts. It is provided. Furthermore, similar tables are held for the other combinations (1-2), (1-3), and (1-4).
The second embodiment also shows the transition of the charging bias control when the two-sheet A4 sheet intermittent durability is performed using the yellow developing cartridge and the specifications of the drum cartridge based on Table 4.
The graph 6-1 is the transition of the charging bias when the drum film thickness is 25 μm to 20 μm in the combinations 1-1 and 1-2 specifications in Table 4. The graph 6-2 shows the transition of the charging bias when the drum film thickness is 20 μm to 15 μm in the combination 1-1 and 1-2 specifications described in Table 4.
Both of the graphs 6-1 and 6-2 show that the correction values are added at the development lives of 90% and 40% shown in Table 6 and the correction is made to the proper charging bias Vpy.
As described above, in the second embodiment, even if the drum cartridge 213 has a variation, the potential of the photosensitive drum 1 can be stably maintained for a long time until the replacement life.

Subsequently, the following verification test was performed in order to verify the effects of Examples 1 and 2.
[Verification test]
A two-unit cartridge used in the electrophotographic image forming apparatus shown in FIG. 1 is a drum cartridge having a drum memory holding the correction information of Examples 1 and 2 and a developing cartridge having a developing memory. And the presence or absence of the generation | occurrence | production of the abnormal image at the time of performing an intermittent paper passing durability test was confirmed.
The image forming apparatus performs image output of 30,000 sheets of A4 image intermittent with 1% of printing ratio (from 100% to 100% of development life) in an environment of low temperature and low humidity (L / L: 15 ° C./10% RH) Image evaluation was performed. The item of image defect refers to a so-called fog image in which toner is developed on a solid white image. The amount of fog was quantified by taping the photosensitive drum with a transparent tape and then measuring the tape with a reflection densitometer (TC-6DS, manufactured by Tokyo Denshoku). In this embodiment, when the fog on the photosensitive drum is 5% or more, fog with an image density that is unacceptable on the paper is generated.

<Verification 1-1>
Table 7 shows a combination of the developing cartridge and the drum cartridge, and the occurrence result of the image defect in the charging control (Example 1, Example 2, control flow 1B, 1C, 1D, 2B, 2C, 2D) at the time of paper feeding.
The developer cartridge and drum cartridge are both used from the new state, the developer cartridge has a development life of 0%, the drum cartridge has a drum A film thickness of 25 μm to 20 μm, and the drum B has a film thickness of 22 μm to 19 μm. is there.
In the table,% indicates the development life% at the occurrence of an abnormal image, and in the case of no occurrence, it is indicated as ○.

<Result of Verification 1-1>
From Table 7, in Examples 1 and 2, appropriate charging bias control was possible without image defects. On the other hand, in the case of the control flows 1B, 1C, 1D, 2B, 2C, and 2D, as the development durability progresses, the charging potential is shifted and fogging occurs. The reason is largely due to the difference in the contamination of the charging roller and the difference in the characteristics of the drum cartridge. Examples 1 and 2
In this case, since the control is performed in consideration of the above, it is possible to obtain a stable drum potential over the entire life of the developing cartridge and the drum cartridge.

<Verification 1-2>
Next, verification 1-2 will be described.
In the verification 1-2, similarly to the verification 1-1, the combination of the developing cartridge and the drum cartridge, and the charging control at the time of paper feeding (Example 1, Example 2, control flow 1B, 1C, 1D, 2B, 2C, The occurrence of image defects in 2D) was verified. In this verification 1-2, the drum cartridge is in use.
In Table 8, the developer cartridge was used from the new state, the drum cartridge A was used up to a film thickness of 20 μm, and the drum cartridge B was used up to a film thickness of 19 μm. This is a result of passing the developing cartridge until the developing life is 0%, the drum cartridge A from 20 μm to 15 μm, and the drum cartridge B from 19 μm to 16 μm.

<Result of Verification 1-2>
As shown in Table 8, in the first and second embodiments, appropriate charging bias control can be performed without image defects. On the other hand, in the case of control flows 1B, 1C, 1D, 2B, 2C, 2D, charging failure has all occurred.
It can be understood that even when a new product is used as the developing cartridge 204, a desired charging potential can not be obtained in a state where the durability deterioration of the photosensitive drum 1 has progressed. In this state, when the endurance progresses, the potential difference occurs even in the case of using the same toner. Even in this state, the modes of the first and second embodiments are controlled in consideration of the above.
It is possible to obtain a stable drum potential.

[Example 3]
Next, Embodiment 3 of the present invention will be described.
In the configurations of the first and second embodiments described above, if the matrix of the drum cartridge 213 is diversified, it may be difficult to store all correction control in the drum memory 150 in terms of storage capacity. Also, when a drum cartridge material is added after the market launch of the image forming apparatus, for example, when the drum film thickness is changed, or when charging rollers having different characteristics are sold as a drum cartridge, images already on the market In the memory tag information held in the forming apparatus or the developing cartridge, it is assumed that it is difficult to cope with charging bias optimization.
The third embodiment is characterized in that the drum memory 150 of the drum cartridge 213 holds the contamination prediction information of all colors in consideration of the difference in the contamination caused by the toner used for each of the drum cartridges 213. is there.
Here, the contamination of the charging roller 2 by the developing container will be described.
The developing cartridge 204 according to the third exemplary embodiment includes a developing blade 21 as a developer regulating member that regulates the amount of toner carried on the developing roller 17. The developing blade 21 is composed of a thin metal plate made of SUS, and is provided so that the vicinity of the free end side is in contact with the outer peripheral surface of the developing roller 17 in a surface contact with a predetermined pressure. The toner carried on the developing roller 17 is given a desired charge by frictional charging when passing through the contact portion with the developing blade 21, and is regulated to a thin layer. The toner layer carried on the developing roller 17 is regulated to a thickness of 6 μm to 20 μm by the developing blade 21.
However, when the toner cannot obtain a desired charge, a problem of fogging that develops the toner on a solid white background occurs. When fogging occurs, the amount of toner collected by the cleaning blade 6 of the drum cartridge 213 increases, and the charging roller 2 becomes dirty.
As the charging roller 2 is contaminated in this way, the charging ability of the charging roller 2 is reduced, the dark portion potential of the photosensitive drum 1 is changed, and the fogging is changed.
Further, in a full-color image forming apparatus, the charging characteristics differ depending on the pigments and external additives used in the toner. For this reason, the difference in charging characteristics also causes a difference in fog depending on the toner used.
In the case of a dual cartridge, which is a feature of the present invention, in particular when the life of the drum cartridge 213 is longer than the life of the developing cartridge 204, if this phenomenon occurs, the life of the drum cartridge 213 can not be extended. However, the present invention makes it possible to solve this problem.
That is, contrary to the first and second embodiments, the first correction information held in the drum memory 150 corresponds to the drum film thickness (lifetime information) of the photosensitive drum 1 and the development life (lifetime information) of the developing cartridge. Are preset. On the other hand, the second correction information held in the development memory 151 is correction information set in advance according to the development life of the development unit.
Similar to the first and second embodiments, the life of the photosensitive drum 1 is longer than that of the developing cartridge 204, and the developing cartridge 204 is replaced in the middle of the life of the photosensitive drum 1. The first correction information is correction information set in advance according to the drum film thickness of the photosensitive drum 1 and the life information of each of the plurality of developing cartridges 204 to be replaced.

<Flow until charging voltage control decision>
Hereinafter, the flow of the charging bias control in the third embodiment will be described with reference to the flowchart shown in FIG. In the third embodiment, the 1st (Y station) operation in the image forming apparatus 200 will be described. Since the operations from 2st to 4sr are also controlled by the same flow, detailed description is omitted.
(S301)
In step S301, the main body power supply of the image forming apparatus 200 is turned on. Thereby, the control unit 2
20 starts charging bias control based on a control program stored in the main body memory 221.
(S302)
In S302, the control unit 220 checks the environment sensor 210, acquires temperature / humidity information in the image forming apparatus 200 detected by the environment sensor 210, and obtains the absolute water content in air as environment data (hereinafter referred to as the water content). Is calculated.
(S303)
In S303, the control unit 220 reads out information (αy) of the reference charging bias corresponding to the calculated water content from the charging table of Table 1. As in the first embodiment, the main body memory 221 of the main body controller 201 holds a charging table based on the film thickness information of the drum and the environmental information.
(S304)
In S <b> 304, the control unit 220 confirms the drum memory 150 by communicating with the drum memory 150 of the drum cartridge 213.
(S305)
In S <b> 305, the control unit 220 confirms the development memory 151 by communicating with the development memory 151 of the development cartridge 204.

The control differs depending on whether the drum memory and the development memory are present or not.
3A: When both the drum memory 150 of the drum cartridge 213 and the development memory 151 of the development cartridge 204 are recognized. 3B: When only the drum cartridge 213 recognizes (installs) the drum memory 150. 3C: Only the development cartridge 204 has the development memory 151. When recognized (mounted) 3D: When neither the drum memory 150 of the drum cartridge 213 nor the developing memory 151 of the developing cartridge 204 could be recognized (mounted) <Case 3A>
In this case, the process proceeds to S306, S307, S308, S309, S310, and S315.
(S306, S307)
(S307)
If the usage status of the developing cartridge 204 can be confirmed in S306, the process proceeds to S307, the temperature and humidity held in the drum memory 150 of the drum cartridge 213, the life information of the developing cartridge 204, and the film thickness information of the drum cartridge 213 ( A first correction value ηy based on the life information is calculated from Table 9.

Table 9 is a correction table as first correction information held in the drum memory 150 of the drum cartridge in the third embodiment. Table 10 is a correction table when Combination 1-1 is used as identification of the cartridge described in Table 4, and is a correction amount in which charging roller contamination is predicted from toner and environmental information.
Although the correction table for the drum cartridge combination 1-1 is shown in Table 10, the correction tables for the combination tables 1-2, 1-3, and 1-4 also exist separately, and together with the combination information at the time of manufacture It is held in the drum memory 150.
(S308,309)
In S309, the use information of the developing cartridge 204 is confirmed, and the second correction value θy of the charging bias based on the temperature and humidity held in the developing memory 151 of the developing cartridge 204 and the use condition (developing life) of the developing cartridge 204 is displayed. 10 from the correction table described in 10.
The durability deterioration tendency of the toner differs depending on the combination of the developing roller 17 and the developing blade to be used. This influence is held as a correction value. Note that all the held values in Table 10 in the third embodiment are set to 0. That is, the charging bias is not corrected according to the developing cartridge specific information. This is because the developing cartridge 204 is less affected by assembly variations at the time of manufacture.

In the third embodiment, the correction memory of Table 10 corresponding to the color of toner used in the developing cartridge 204 is held in the developing memory 151. For example, a yellow developing cartridge holds a yellow table, and a magenta developing cartridge holds a magenta table. This is possible by manufacturing the toner color used in assembling the developing cartridge in correspondence with the developing memory 151.
In this way, by associating with each other at the time of manufacture, it is not necessary to hold unnecessary information in the development memory 151, and the storage capacity of the memory can be reduced.
Further, in the case where the association at the time of manufacturing is not performed, all the correction tables in Table 10 are held in the development memory 151, so that it is possible to control which color developer cartridge is assembled.
(S310, S315)
In step S310, the reference charging bias value αy calculated in step S303, the first correction value (ηy) calculated in step S307, and the second correction value θy calculated in step S309 are used. The charge application bias (Vpy) is calculated.
<Calculation Formula> Charging Application Bias Vpy = αy + ηy + θy (4)
Next, the process proceeds to S <b> 315, and a bias is applied to the charging roller 2 by the control unit 220 based on the charging application bias Vpy calculated by the main body controller 201.
By performing the control described above, the potential of the photosensitive drum can be stably maintained over a long lifetime.

<In the case of 3B>
(When only the drum memory of the drum cartridge is recognized (mounted))
In this case, the process proceeds to S306, S307, S308, S311, and S315.
That is, S306 and S307 are the same as in the case of 3A, and the first correction value ηy is calculated. Since the information of the developing memory 151 of the developing cartridge 204 cannot be obtained in S308, the process proceeds to step 311.
Since the development memory information of the development cartridge can not be obtained, θy becomes unstable in the above calculation formula (4). Furthermore, with respect to ηy, the table cannot be referenced because there is no usage information of the developing cartridge. In this case, the development life is controlled as an initial value.
Therefore, when only the drum unit of 3B recognizes the memory tag, the charging mark bias to be applied is determined by the following calculation formula (5).
Charging application bias V′py = αy + η′y (5)
In addition, since all the holding values of the table of Table 10 in the present Example 3 are set to 0, it becomes V'py = (alpha) y after all.
Next, in S <b> 315, the control unit 220 controls to apply the charging application bias V′py calculated in S <b> 311 to the charging roller 2.

<In the case of 3C>
(Only when developing cartridge is recognized (mounted) developing memory)
In this case, the process proceeds to S306, S312, S313, and S315.
That is, since the information of the drum memory 150 can not be obtained in S306, the process proceeds to S312, and the development memory is confirmed. If the development memory is confirmed, the process proceeds to step S313.
Since the information of the drum memory 150 is not obtained, the first correction value ηy is undefined in the calculation formula (4). Further, since there is no film thickness information (lifetime information) of the photosensitive drum, Table 10 can not be referred to. In this case, the life of the photosensitive drum is controlled as an initial value, and the charging application bias to be applied is determined by the following calculation formula (6).
Charging application bias V′py = αy + θy (6)
Next, in step S315, the control unit 220 controls the charging roller 2 to apply the charging application bias V'py calculated in step S313.

<For 3D>
(If neither the drum memory of the drum cartridge nor the developing memory of the developing cartridge can be recognized (mounted))
In this case, the drum memory recognition step (S306) and the development memory recognition step (S312) both become (none), and the process proceeds to S314.
Since neither the drum memory 150 nor the development memory 151 can be recognized, αy, ηy, and θy are all indefinite in the calculation formula (4).
Therefore, in (S314),
<Calculation Formula> It is determined that the charging application bias V'py = undefined.
In this case, as in the first embodiment, the charging application bias V′py is controlled by the bias shown in Table 16 preset in the main body controller 201.
That is, in S315, the control unit 220 performs control so that the charging application bias V′py calculated in S314 is applied to the charging roller 2.

Example 4
The charge correction control in the fourth embodiment is characterized in that Table 11 is used as the developing cartridge offset table in (S307) described in the third embodiment.
That is, this is a correction value of the charging bias according to the information specific to the developing cartridge, and takes into account that the tendency of the toner to deteriorate due to the combination of the developing roller and the developing blade used. As described above, there are a plurality of factors that affect the charge of the toner, but in this embodiment, the contact pressure of the developing blade and the surface roughness of the developing roller are dominant. For this reason, as the toner contamination factor of the charging roller, the range of the contact pressure of the developing blade and the surface roughness of the developing roller are divided into two levels, and the respective correction amounts are held in the memory tag.
The development key parts combination held in the memory tag of the development cartridge is a table shown in Table 11. In the memory tag of development, a table of combinations of 3-1 to 3-4 is held below, and each has its own correction value.

The details of Table 11 are as follows.
Development roller surface roughness range C: Surface roughness standard 8 to 19 (μm)
Development roller surface roughness range D: Surface roughness standard 19 to 30 (μm)
The developer roller used in the fourth embodiment is the developing roller 17 used together with the negatively chargeable developer, and the conductive core, the elastic layer, and the conductive urethane resin layer which is the surface layer. And have.
(Shaft core)
The shape of the shaft core is a columnar shape or a hollow cylindrical shape, and is made of the following conductive material. Metal or alloy such as aluminum, copper alloy, stainless steel; iron plated with chromium or nickel; synthetic resin having conductivity. A well-known adhesive may be suitably applied to the surface of the mandrel in order to improve the adhesion to the elastic layer provided on the outer peripheral surface thereof.
[Elastic layer]
The elastic layer contains an elastic material such as resin and rubber. Specifically as resin and rubber | gum, the following is mentioned, for example. Polyamide, nylon, polyurethane resin, urea resin, polyimide, melamine resin, fluorine resin, phenol resin, alkyd resin, polyester, polyether, acrylic resin, and mixtures thereof. Ethylene-propylene-diene copolymer rubber (EPDM), acrylonitrile-butadiene rubber (NBR), chloroprene rubber (CR), natural rubber (NR), isoprene rubber (IR), styrene-butadiene rubber (SBR), fluorine rubber, silicone Rubber, epichlorohydrin rubber, hydride of NBR. Among these, polyurethane resins are preferable because they are excellent in frictional charging performance to toner and excellent in flexibility, so that they can easily get a chance to contact with the toner and have abrasion resistance. Also, when the elastic layer has a laminated structure of two or more layers, it is preferable to use a polyurethane resin as the outermost elastic layer. Examples of the polyurethane resin include ether polyurethane resins, ester polyurethane resins, acrylic polyurethane resins, fluorine polyurethane resins, carbonate polyurethane resins, and olefin urethane resins.
The polyurethane resin can be obtained from a polyol and an isocyanate, and a chain extender can be used as necessary. Polyol which is a raw material of polyurethane resin includes polyether polyol, polyester polyol, polycarbonate polyol, polyolefin polyol, acrylic polyol, and mixtures thereof. As an isocyanate which is a raw material of a polyurethane resin, the following is mentioned, for example. Tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), naphthalene diisocyanate (NDI), tolidine diisocyanate (TODI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), phenylene diisocyanate (PPDI), xylylene diisocyanate (XDI) , Tetramethylxylylene diisocyanate (TMXDI), cyclohexane diisocyanate, and mixtures thereof. As a chain extender which is a raw material of polyurethane resin, ethylene glycol, 1,4-butanediol, difunctional low molecular weight diol such as 3-methylpentanediol, trifunctional low molecular weight triol such as trimethylolpropane, and the like A mixture is mentioned.

Moreover, when making an elastic layer into laminated constitution of two or more layers, as a material which comprises the elastic layer (lower layer) 4 on an axial core, silicone rubber is preferable. As silicone rubber, polydimethylsiloxane, polymethyl trifluoropropyl siloxane, polymethyl vinyl siloxane, polyphenyl vinyl siloxane, and a copolymer of these siloxanes can be mentioned. These resins and rubbers can be used alone or in combination of two or more as required. The materials of the resin and rubber can be identified by measurement using a Fourier transform infrared spectrophotometer.
In the elastic layer, if necessary, particles, a conductive agent, a plasticizer, a filler, an extender, a vulcanizing agent, a vulcanization aid, a crosslinking aid, a curing inhibitor, an antioxidant, an antiaging agent, and the like. Various additives such as agents, processing aids, etc. can be included. These optional components can be blended in amounts that do not inhibit the function of the elastic layer.
By including particles in the elastic layer, a convex portion can be formed on the surface of the electrophotographic member. The particles that can be added to the elastic layer preferably have a volume average particle diameter of 1 μm or more and 30 μm or less. The particle diameter can be measured by observing the cross-sectional surface with a scanning electron microscope (trade name: JSM-7800 FPRIME Schottky field emission scanning electron microscope, manufactured by Nippon Denshi Co., Ltd.).
The amount of the particles contained in the elastic layer is preferably 1 part by mass or more and 100 parts by mass with respect to 100 parts by mass of the elastic material such as resin or rubber. As the particles, fine particles made of a resin such as polyurethane resin, polyester, polyether, polyamide, acrylic resin, and polycarbonate can be used. Among these, polyurethane resin particles are preferable because they are soft and have abrasion resistance.
The elastic layer can be a conductive elastic layer in which a conductive agent such as an electron conductive substance or an ion conductive substance is blended with the above elastic material. Examples of the electronic conductive material include the following materials. Conductive carbon, for example, ketjen black EC, carbon black such as acetylene black; SAF (Super Abrasion Furnace), ISAF (Intermediate SAF), HAF (High Abrasion)
Furnace), FEF (Fast Extracting Furnace), GPF (General Purpose Furnace), SRF (Semi-Reinforming Furnace), FT (Fine Thermal), MT (Medium Thr) ) Carbons; metals such as copper, silver, germanium and their metal oxides. Among these, conductive carbon is preferable because the conductivity can be easily controlled with a small amount. Examples of the ion conductive material include the following materials. Inorganic ionic conductive materials such as sodium perchlorate, lithium perchlorate, calcium perchlorate and lithium chloride; organic ionic conductive materials such as modified aliphatic dimethylammonium ethosulphate and stearylammonium acetate.
Examples of the filler include silica, quartz powder, and calcium carbonate.
The materials for the elastic layer are mixed using a uniaxial continuous kneader, a biaxial continuous kneader, a double roll, a kneader mixer, a dynamic mixing device such as a trimix, or a static mixing device such as a static mixer. be able to.

Examples of the method for forming the elastic layer on the mandrel include a die molding method, an extrusion molding method, an injection molding method and a coating molding method. A method for forming the first region for forming the convex portion will be described later. In the molding method, for example, first, a piece for holding an axial core in a mold is fixed to both ends of a cylindrical mold, and an injection port is formed in the piece. Then, after the mandrel is placed in the mold and the material for the elastic layer is injected from the injection port, the mold can be heated at a temperature at which the material hardens to be demolded. In the extrusion molding method, for example, a material for the shaft core body and the elastic layer can be extruded together using a crosshead type extruder, and the material can be cured to form an elastic layer around the shaft core body. .
When the elastic layer has a laminated structure of two or more layers, the surface of the elastic layer (lower layer) on the shaft core side may be polished to improve adhesion, and the surface of corona treatment, frame treatment, and excimer treatment It can also be modified by a modification method.
In this embodiment, by setting the surface roughness of the developing roller 17 to 10-point average roughness (JIS) Rz = 8 to 30 (μm), an appropriate value is obtained as the toner coat amount on the developing roller 17. It was. In view of this, the charging correction value is set to two levels in accordance with the surface roughness of the developing roller 17. This level is not limited to two levels, and may be changed as appropriate according to the storage capacity and development characteristics of the memory tag.

Development blade pressure range C: Development blade pressure 10 to 20 (kgf / cm)
Development blade pressure range D: Development blade pressure 20 to 40 (kgf / cm)
<Configuration of development blade>
In this embodiment, the developing blade 21 is a leaf spring-like SUS thin plate having a free length in the short direction of 8 mm and a thickness of 0.08 mm. Here, the developing blade is not limited to this, and may be a thin metal plate such as phosphor bronze or aluminum.
A predetermined voltage is applied to the developing blade 21 from a blade bias power source (not shown) to stabilize the toner coat, and V = −500 V is applied as the blade bias.
Here, with reference to the schematic diagram of FIG. 4B, a method of changing the pressure N (gf / mm) against the developing roller 17 in the developing blade 21 will be described. The schematic view is an explanatory view of the positional relationship between the developing blade 21 and the developing roller 17.
As shown in the schematic view, a coordinate system in a cross section perpendicular to the rotation axis of the developing roller 17 is considered. That is, in the cross section, a direction substantially parallel to the direction in which the developing blade 21 extends while being pressed against the developing roller 17 is a y-axis, and a direction perpendicular to the y-axis is an x-axis. The origin is the rotation center O of the developing roller 17 and a coordinate system in which the center coordinates of the developing roller 17 are (x, y) = (0, 0). In this coordinate system, the position of the development blade tip 21b in the x-axis direction is taken as an X value, and the position in the y-axis direction is taken as a Y value. The pressure contact pressure N (gf / mm) was changed by changing the X value and the Y value.

<Measurement method of pressure contact>
In the case of measuring the pressing pressure N (gf / mm) against the developing roller 17 in the developing blade 21, the developing device from which the developing roller 17 was removed was mounted on a dedicated measuring jig. Then, an aluminum sleeve having a diameter equal to that of the developing roller 17 was prepared as a virtual developing roller, and measured by bringing the developing blade 21 into contact.
The length of the measuring element is 50 mm, and the contact pressure of the toner supply roller 20 is calculated from the average value at the measurement points at the two ends and the center three points.
Table 12 shows the relationship between the pressure N (gf / mm) against the developing roller and the X value and Y value of the developing blade tip 21b in the developing blade in this example.

In this embodiment, in the developing blade, the toner to be used is set by setting the pressing pressure N (gf / mm) against the developing roller between 2.0 (gf / mm) and 4.0 (gf / mm). It was possible to charge as desired.
Thus, by designing the surface roughness of the developing roller 17 and the contact pressure of the developing blade 21 in such a range that the toner can obtain a desired charge, a problem of fogging that the toner is developed on a solid white background Can be suppressed. As a result, the amount of toner collected by the cleaning blade 6 of the drum cartridge 213 is reduced, so that contamination of the charging roller 2 can be suppressed.
Therefore, stable charging control can be performed even with the dual cartridge, which is a feature of the present invention, particularly when the life of the drum cartridge 213 is longer than the life of the developing cartridge 204.
In the fourth embodiment, a correction amount due to a toner deterioration factor is provided which is caused by the difference between the surface roughness of the developing roller 17 and the blade pressure of the developing blade 21. The present invention is not limited to this, and is also suitable as a correction table based on other parameters.
For example, in the case of the hardness, flare, resistance, and developing blade 21 of the developing roller 17, the surface roughness, the environmental characteristics of the material, the environmental characteristics of the hardness, and the like.

Table 13 shows the correction table held in the development memory 151 of the development cartridge 204 in the fourth embodiment.
The correction table holds correction values according to the development life according to the environment for each combination of the developing roller 17 and the developing blade 21 of the developing cartridge 204 according to the color of each toner.
In the fourth embodiment, the color of toner used in the developing cartridge 204 and a table for each combination of the developing roller 17 and the developing blade 21 used in the developing cartridge 204 are held in the developing memory 151. There is.

For example, when the yellow developing cartridge 204 has a developing roller 17 having a surface roughness of 8 to 19 μm and a developing blade pressure of 15 to 25, the combination 3-1 in Table 11 and the Yellow table are displayed. Hold. Similarly, in the magenta developing cartridge 204, when the developing roller 17 has a surface roughness of 19 to 30 μm and the developing blade pressure is 25 to 40, the Magenta correction table of combination 3-4 in Table 11 is developed. Memory 151
Hold on.
As described above, the toner color, the developing roller roughness information, and the developing blade pressure information used in assembling the developing cartridge 204 can be manufactured by associating the developing memory 151 with each other. As described above, by correlating at the time of manufacture, it is possible to reduce the capacity of the memory without holding unnecessary information in the development memory 151.
Further, when the association at the time of manufacturing is not performed, all the correction tables in Table 13 are held in the development memory 151, so that it is possible to control which color developer cartridge is assembled.
By performing the control described above, correction control is performed in consideration of manufacturing variations of the developing cartridge 204, so that the potential of the photosensitive drum 1 can be stably maintained over a long life.

Also in the third and fourth embodiments, when at least one of the drum memory and the development memory can not be recognized, or the following control is performed depending on the difference in the memory holding mode.
With this control, it is possible to perform an image forming operation in the image forming apparatus. However, it is insufficient as a control for charge potential stabilization, and it is difficult to obtain an appropriate dark area potential throughout the life. For this reason, it is necessary to be able to recognize the memory tag of both the drum cartridge and the developing cartridge.

Subsequently, in order to verify the effects of Examples 3 and 4, the following verification test 2 was performed.
[Verification test 2]
Similar to the verification test 1, the two-unit cartridge used in the electrophotographic image forming apparatus shown in FIG. 1 and the cartridge having the memory tag holding the correction information of the present embodiment is used. The presence or absence of the occurrence of abnormal images was confirmed.
The image forming apparatus performs image output of 30,000 sheets of A4 image intermittent with 1% of printing ratio (from 100% to 100% of development life) in an environment of low temperature and low humidity (L / L: 15 ° C./10% RH) Image evaluation was performed. The item of image defect refers to a so-called fog image in which toner is developed on a solid white image. The amount of fog was quantified by taping the photosensitive drum with a transparent tape and then measuring the tape with a reflection densitometer (TC-6DS, manufactured by Tokyo Denshoku). In this embodiment, when the fog on the photosensitive drum is 5% or more, fog with an image density that is unacceptable on the paper is generated.
<Verification 2-1>
Table 14 shows the results of image defects in combinations of developer cartridges and drum cartridges, and charging control during sheet feeding (Examples 3 and 4 and conventional controls 3B, 3C, 3D, 4B, 4C, and 4D). As the drum cartridge, the drum cartridge of the combination 1-1 described in Examples 1 and 2 was used.
In Table 14, both the development cartridge and the drum cartridge are used from the new state, the development cartridge has a development life of 0%, and the drum cartridge has a drum A with a film thickness of 25 μm to 20 μm. Note that% in the table indicates the development life% at the time of occurrence of an abnormal image, and when there is no occurrence, it is indicated as ○.

<Result of Verification 2-1>
From Table 14, in this embodiment, appropriate charging bias control is possible without image defects. On the other hand, in the conventional implementation control, charging failure has occurred.
The control in the conventional mode indicates that as the durability of development progresses, the charging potential is shifted and fogging occurs. That is, it is largely due to the difference in dirt on the charging member and the difference in the characteristics of the drum cartridge. Since this embodiment is controlled in consideration of the above, it is possible to stably obtain the drum potential throughout the life of the developing machine and the drum cartridge.

<Verification 2-2>
In the verification 2-2, similarly to the verification 2-1, the combination of the developing cartridge and the drum cartridge, and the charging control at the time of paper feeding (Example 3, Example 4, control flow 3B, 3C, 3D, 4B, 4C, The occurrence of image defects in 4D) was verified. In this verification 2-2, the drum cartridge is in use.
Table 15 shows the results when the developing cartridge is used from the new state, and the drum cartridge A is passed from the film thickness of 20 μm to 15 μm until the developing life is 0%.

<Result of verification 2-2>
As shown in Table 15, in this embodiment, appropriate charging bias control can be performed without image defects. On the other hand, in the conventional implementation control, charging failure has occurred.
It can be seen that when the durability deterioration of the photosensitive drum has progressed, the desired charging potential can not be obtained even if the developing cartridge is new. In this state, when the endurance progresses, the potential difference occurs even in the case of using the same toner.
Also in this state, the modes of the third and fourth embodiments are controlled in consideration of the above, so that it is possible to obtain a stable drum potential throughout the life of the developing machine.

As described above, the problems of the prior art can be solved in the embodiment of the present invention described above. In other words, when charging control information is stored in the memory of the image forming apparatus main body and potential stabilization control is performed, if the specifications of the photosensitive drum, charging roller, etc. are changed after launch, appropriate charging control is performed. In order to make the memory tag of the cartridge hold the control information, it is possible to perform appropriate potential control.
In addition, even when the photoconductor memory and the development memory are arranged in the photoconductor cartridge and the development cartridge, respectively, the decrease in charging ability due to the contamination of the charging roller unique to the photoconductor cartridge is based on the correction control held in the memory. It can control appropriately.
Further, the contamination information of the charging roller for each toner used is stored in the drum memory of the drum cartridge for all the colors, so that the toner used in the station of the image forming apparatus to be used and the developing cartridge to be paired can be used. It can be used as a so-called universal that can be used flexibly without depending on the color and the like.

DESCRIPTION OF SYMBOLS 1 ... Photoconductor drum 2 ... Charging roller 3 ... Scanner unit 5 ... Intermediate transfer belt 6 ... Cleaning blade 150 Drum memory 151 ... Development memory 200 ... Image forming apparatus 201 ... Main body controller 210 ... Warm Humidity sensor 220 ... Main body control unit 204 ... Development cartridge 213 ... Drum cartridge 217 ... Development roller

Claims (18)

An image carrier unit having at least an image carrier and a charging member, and a developing unit having at least a developer carrier are each independently detachable from the apparatus main body of the image forming apparatus,
The apparatus main body has a control means,
The image carrier unit has a first storage member for holding first correction information according to the life information of the image carrier,
The developing unit has a second storage member that holds second correction information according to the life information of the developing unit.
The control means acquires the first correction information stored in the first storage member and also acquires the second correction information from the second storage member, and the acquired first correction information and the second correction information And correcting the charging bias and applying the corrected charging bias to the charging member. The control means includes a storage unit that stores in advance reference information of a charging bias applied to the charging member;
The image forming apparatus according to claim 1, wherein the control unit corrects the charging bias based on the reference information acquired from the storage unit using the first correction information and the second correction information. The first correction information held in the first storage member is correction information set in advance according to the life information of the image carrier,
2. The second correction information held in the second storage member is correction information set in advance according to the life information of the developing unit and the life information of the image carrier. The image forming apparatus according to 2. The life of the image carrier is longer than the life of the development unit, and the development unit is replaced during the life of the image carrier.
4. The image according to claim 3, wherein the second correction information is correction information set in advance according to the life information of the image carrier and the life information of each of the plurality of developing units to be replaced. 5. Forming equipment.   5. The image forming apparatus according to claim 1, wherein the first correction information corresponds to a characteristic charging characteristic of the image carrier unit. 6.   6. The image forming apparatus according to claim 5, wherein the charging characteristics specific to the image carrier unit are in accordance with a combination of the type of the image carrier and the type of the charging member.   The image forming apparatus according to claim 4, wherein the first correction information corresponds to a charging characteristic unique to the image carrier unit.   The image forming apparatus according to claim 7, wherein the charging characteristics unique to the image carrier unit are in accordance with a combination of the type of the image carrier and the type of the charging member. The first correction information held in the first storage member is correction information set in advance according to the life information of the image carrier and the life information of the developing unit,
The image forming apparatus according to claim 1, wherein the second correction information held in the second storage member is correction information set in advance according to the life information of the developing unit. The life of the image carrier is longer than the life of the development unit, and the development unit is replaced during the life of the image carrier.
10. The image according to claim 9, wherein the first correction information is correction information set in advance according to the life information of the image carrier and the life information of each of a plurality of developing units to be exchanged. Forming device.   11. The image forming apparatus according to claim 9, wherein the second correction information held in the second storage member is in accordance with a characteristic characteristic of the developing unit. The developing unit includes a developer carrying member and a developer regulating member that regulates the developer layer in pressure contact with the developer carrying member,
12. The image forming apparatus according to claim 11, wherein the characteristic characteristic of the developing unit is a combination of a type of the developer carrying member and a type of the developer regulating member.   13. The control unit corrects the charging bias using the acquired correction information when either of the first correction information and the second correction information cannot be acquired. 13. The image forming apparatus according to any one of the above.   The image forming apparatus according to claim 2, wherein a plurality of types of the charging bias reference information, the first correction information, and the second correction information are set in advance according to environmental information. The device body is provided with detection means for detecting environmental information;
The control means acquires environment information from the detection means, acquires the first correction information and the second correction information according to the acquired environment information, and the first correction information according to the acquired environment information. The image forming apparatus according to claim 14, wherein the reference information of the charging bias is corrected using the second correction information.   The image forming apparatus according to claim 2, wherein the charging bias reference information, the first correction information, and the second correction information are provided in a plurality of types according to the color of the developer. The apparatus body has a plurality of imaging units for forming images of different colors;
The image forming apparatus according to claim 16, wherein the color of the image carrier unit is determined by an image forming unit to be mounted.   The image forming apparatus according to claim 1, wherein the first storage member and the second storage member have the same storage capacity.