JP7254506B2 - image forming device - Google Patents

Description

The present invention relates to an electrophotographic image forming apparatus in which a detachable process cartridge is composed of an image carrier unit and a developing unit. Examples of image forming apparatuses include copiers, printers (laser beam printers, LED printers, etc.), facsimile machines, word processors, and multifunction machines (multifunction printers).

In an electrophotographic image forming apparatus, for the purpose of simplifying replacement maintenance of consumables such as photoreceptors and toners, cleaning means including a toner storage unit, developing means, photoreceptor, charging means, and waste toner container are installed. , and a system in which the cartridge is integrated as a process cartridge and configured to be detachable from the image forming apparatus is known. Also known is a form in which a storage means (memory) is installed in a process cartridge to manage cartridge information.
For example, in the image forming apparatus disclosed in Japanese Patent Application Laid-Open No. 2002-200012, a storage means provided in a process cartridge stores information on parameter values for changing conditions unique to each process cartridge as information for changing image forming process conditions. Techniques for storing are disclosed.
Further, in the image forming apparatus described in Patent Document 2, the process cartridge is equipped with a non-volatile storage means that can be read/written from/to the apparatus body for the purpose of stabilizing the potential of the photosensitive drum (image carrier). . The storage means stores information such as charging characteristics, mechanical characteristic values, types, etc. of the charging member, and controls charging of the photosensitive drum by switching charging bias conditions applied to the charging member according to this information. is disclosed.
Further, Japanese Patent Application Laid-Open No. 2002-100000 discloses a storage means for storing the characteristics of a photosensitive drum, and a control for correcting the conditions of a charger, an optical unit, a developing unit, or a transfer roller according to the characteristics of the photosensitive drum. An image forming apparatus is disclosed that includes a control means for

Japanese Patent Application Laid-Open No. 2001-117425 JP-A-9-190140 JP-A-2000-47459

In recent years, with the diversification of user needs, there is a two-part form in which process cartridges are divided into two for each function as a form of an image forming apparatus using an electrophotographic image forming process. For example, a photoreceptor unit (image carrier unit) having at least a photoreceptor drum (image carrier), and a developing unit in which developing means and a toner container for containing toner to be used are integrated, are each formed into an apparatus main body. There is a form that is detachable. Compared to the conventional process cartridge in which the photoreceptor unit and the developing unit are integrated, each unit of such a two-piece unit can be used with an individual replacement life when, for example, each unit has a different life. There are benefits you can do.
In order to maintain the potential stability of the photoreceptor drum for a long period of time in the image forming apparatus having the dual structure having such advantages, the following problems arise.
In general, the production of consumables such as photoreceptor units and developing units continues even after production of the image forming apparatus ends. At this time, if the specifications of the photoreceptor drum, charging roller, etc. are changed depending on the material procurement situation, the control information for performing appropriate charging control may be changed. For example, when the film thickness of the photoreceptor drum used is changed, or when the hardness of the photoreceptor drum is changed, the scraping speed is changed.
However, when the process cartridge is separated into a photoreceptor unit and a developing unit, and units with different specifications are distributed in the market, the combination depends on which unit the user purchases and installs in the image forming apparatus. do. As described above, the specifications of the photoreceptor drum and charging roller may change due to various factors, and if the combination of units cannot be predicted, the image forming apparatus cannot perform appropriate control.
SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus capable of maintaining more appropriate control and performing good image formation when a process cartridge is integrated into an image carrier unit and a developing unit. .

In order to achieve the above object, the present invention
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 independently attachable to and detachable from an apparatus main body of the image forming apparatus,
the apparatus main body has control means for controlling the charging bias applied to the charging member ;
The image carrier unit has a first storage member that holds first correction information used for correcting the charging bias according to life information of the image carrier ,
The developing unit corrects the charging bias according to life information of the developing unit.
having a second storage member for holding second correction information to be used ;
The apparatus main body holds a reference charging bias according to reference information serving as a reference of the charging bias when the charging bias is corrected based on the first correction information and the second correction information. having a memory,
The control means acquires the first correction information stored in the first storage member, acquires the second correction information from the second storage member, and stores the acquired first correction information and the second correction. A correction amount of the charging bias calculated from the information is acquired , and control for correcting the charging bias is executed based on the reference charging bias and the correction amount of the charging bias.

According to the present invention, in the case where the process cartridge is integrated into the image carrier unit and the developing unit, more appropriate control can be maintained and good image formation can be performed.

1 is a schematic cross-sectional view of an image forming apparatus to which the present invention is applied; FIG. (A) is an external view of a drum cartridge, and (B) is a schematic sectional view. Schematic diagram of developer cartridge. (A) is a cross-sectional view of a developing cartridge, and (B) is a schematic diagram of a developing blade. FIG. 2 is a control block diagram of the apparatus of FIG. 1; 4 is a flowchart of correction control in the first embodiment; 5 is a graph of the reference charging bias for Example 1; 5 is a graph of charging bias with the first correction value of Example 1 taken into account; 6 is a graph of charging bias with the second correction value of Example 1 taken into account; 8 is a graph of charging bias with the second correction value of Example 2 taken into account; 10 is a flowchart of correction control in Example 3; 7 is a graph of charging bias without the correction of FIG. 6; 8 is a graph of charging bias for different colors of FIG. 7;

The present invention will be described in detail below with reference to the illustrated embodiments.
The image forming apparatus forms an image on a recording medium using, for example, an electrophotographic image forming process. Examples include electrophotographic copiers, electrophotographic printers (eg, LED printers, laser beam printers, etc.), electrophotographic facsimile machines, and the like.
Further, the term "cartridge" refers to a cartridge that can be attached to and detached from the main body of the image forming apparatus. Among cartridges, a cartridge in which a photosensitive drum and process means acting on the photosensitive drum are integrated is called a drum cartridge (drum unit). Further, a unit in which process means related to development are integrated is called a developing cartridge (developing unit).
Further, the following embodiment exemplifies a full-color image forming apparatus in which four sets of drum cartridges and developing cartridges are attachable and detachable. However, the number of drum cartridges and developing cartridges to be mounted on the image forming apparatus is not limited to this. Likewise, the materials, arrangements, dimensions, and other numerical values of each configuration disclosed in the examples are not limited unless otherwise specified. Further, unless otherwise specified, the upper side indicates the upper side in the gravitational direction 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 an image forming apparatus 200. As shown in FIG. As shown in FIG. 1, an image forming apparatus 200 has a plurality of image forming units, each of which forms an image of each color of yellow (Y), magenta (M), cyan (C), and black (K). It has second, third and fourth imaging units SY, SM, SC and SK. In this embodiment, the first to fourth image forming units SY, SM, SC, and SK are arranged in a row substantially horizontally. Drum cartridges 213 (213Y, 213M, 213C and 213K) and developing cartridges 204 (204Y, 204M, 204C and 204K) are provided in each of the imaging units SY, SM, SC and SK. In this embodiment, the drum cartridges 213 (213Y, 213M, 213C, 213K) and the developing cartridges 204 (204Y, 204M, 204C, 204K) are configured and operated substantially the same except that the colors of the formed images are different. essentially the same. Therefore, hereinafter, Y, M, C, and K will be omitted and a general description will be given unless a particular distinction is 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 slightly inclined direction with respect to the horizontal direction. A unit (exposure device) 3 is arranged.
The developing cartridge 204 and the drum cartridge 213 are guided by guides such as mounting guides and positioning members (not shown) provided on the main body frame of the image forming apparatus main body 200A, and are independent of each other with respect to the image forming apparatus main body 200A. is detachable. The developer cartridges 204 for respective colors contain toners of yellow (Y), magenta (M), cyan (C), and black (K), respectively.
Around the photosensitive drum 1 of the drum cartridge 213 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. 204 developing rollers 17 are arranged.

The charging roller 2 is charging means (charging device, charging member) that uniformly charges the surface of the photosensitive drum 1 . Exposure means (exposure device, 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 this embodiment). The charging bias determination process will be described later. The charging bias used in this embodiment is a direct voltage (DC), but is not limited to this, and may be a so-called AC+DC superimposed voltage in which an alternating voltage is superimposed on a direct 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 developer. In this embodiment, a non-magnetic one-component developer (hereinafter referred to as toner) is used as the developer, and a contact development method is adopted in which a developing roller 17 as a developer carrying member is brought into contact with the photosensitive drum 1 . .
Further, an intermediate transfer member serving as an intermediate transfer member for transferring the toner image on the photosensitive drum 1 to face 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 contacts the photosensitive drums 1 of the drum cartridges 213 and rotates (moves) in the direction of arrow B in FIG. The intermediate transfer belt 5 is stretched over a plurality of supporting members (driving roller 51, secondary transfer counter roller 52, driven roller 53). Four primary transfer rollers 8 as primary transfer means are arranged side by side on the inner peripheral surface side of the intermediate transfer belt 5 so as to face each photosensitive drum 1 . A secondary transfer roller 9 as a secondary transfer means is arranged at a position facing the secondary transfer opposing roller 52 on the outer peripheral surface side of the intermediate transfer belt 5 .

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 source (not shown) within the main body of the image forming apparatus. Next, the charged surface of the photoreceptor drum 1 is scanned and exposed by laser light emitted from the scanner unit 3 according to image information. As a result, an electrostatic latent image corresponding to 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 developer 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 in the four drum cartridges 213 (213Y, 213M, 213C, 213K) and developer cartridges 204 (204Y, 204M, 204C, 204K). The toner images of the respective colors formed on the photosensitive drums 1 of the drum cartridges 213 are sequentially primary-transferred so as to be superimposed on the intermediate transfer belt 5 . After that, 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 fixing means. A 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, 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, secondary transfer residual toner remaining on the intermediate transfer belt 5 after the secondary transfer process is removed by the cleaning device 11 for the intermediate transfer belt 5 . Note that the image forming apparatus 200 is also capable of forming monochromatic or multicolor images using a single or some (but not all) imaging units as desired.
Further, the image forming apparatus 200 is provided with an environment sensor 210 as means for measuring the temperature and humidity as the environment inside the main body, and the main body controller 201 has a control unit for calculating the absolute amount of water as environmental information from the temperature and humidity. 220 are arranged. The environment sensor 210 detects the current temperature and humidity, and obtains the absolute amount of moisture in the air from the temperature (°C) and relative humidity (%RH). Incidentally, the absolute water content is 21.5 g at 30°C and 80% RH under atmospheric pressure of 760 mmHg; 1.1 g at 15°C and 10% RH; and 11.8 g at 25°C and 60% RH. .
In this embodiment, the environment sensor 210 is installed inside the image forming apparatus 200 to detect the temperature and humidity inside the image forming apparatus 200 . The charging voltage may be controlled based on the temperature and humidity outside the image forming apparatus 200 .

[Structure of Drum Cartridge and Developing Cartridge]
Next, the drum cartridges 213 (213Y, 213M, 213C, 213K) and developing cartridges 204 (204Y, 204M, 204C, 204K) shown in FIG. 1 will be described with reference to FIGS.
The drum cartridge 213Y, drum cartridge 213M, drum cartridge 213C, and drum cartridge 213K have the same configuration and can be used regardless of color. Developing cartridge 204Y containing yellow toner, developing cartridge 204M containing magenta toner, developing cartridge 204C containing cyan toner, and developing cartridge 204K containing black toner are the same except for the toner. Configuration. Accordingly, 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. Each cartridge constituent member will also be generically described in the same way.

Drum Cartridge FIG. 2 is an external perspective view of the drum cartridge 213 . Here, as shown in FIG. 2, the rotation axis direction of the photosensitive drum 1 is the Z direction (arrows Z1 and Z2), the horizontal direction in FIG. 1 is the X direction (arrows X1 and X2), and the vertical direction in FIG. is the Y direction (arrow Y1, arrow Y2).
Drum unit bearing members 239R and 239L are attached to both sides of the cleaning frame 214, respectively, and support the photosensitive drum unit 203, respectively. As a result, the photosensitive drum unit 203 is rotatably supported by the cleaning frame 214 .
Also, the charging roller 2 and the cleaning blade 6 are attached to the cleaning frame 214 and are arranged so as to contact the surface of the photosensitive drum 1 . Also, charging roller bearings 15L and 15R are attached to the cleaning frame 214 . The charging roller bearings 15</b>L and 15</b>R are bearings for supporting the shaft of the charging roller 2 .
Here, the charging roller bearings 15L and 15R are attached so as to be movable in the direction of arrow C shown in FIG. 2(B). A rotating shaft 2 a of the charging roller 2 is rotatably attached to a 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 abuts against the photosensitive drum 1 and rotates following the photosensitive drum 1 .
The cleaning frame 214 is provided with a cleaning blade 6 as cleaning means for removing toner remaining on the surface of the photosensitive drum 1 . The cleaning blade 6 is formed by integrating a blade-shaped rubber (elastic member) 6a that contacts the photosensitive drum 1 to remove the toner on the photosensitive drum 1 and a supporting metal plate 6b that supports it. In this embodiment, the supporting metal plate 6b is fixed to the cleaning frame 214 with screws.
As described above, the cleaning frame 214 has an opening 214 b for collecting the transfer residual toner collected by the cleaning blade 6 . The collected residual toner is stored in a removed developer storage portion (hereinafter referred to as a waste toner storage portion) 214a through an opening 214b. The waste toner container 214a and the cleaning blade 6 are integrated to form a drum cartridge 213. As shown in FIG. The opening 214b is provided with a blowout prevention sheet 26 that abuts against the photosensitive drum 1 and seals between the photosensitive drum 1 and the opening 214b, thereby preventing toner leakage upward from the opening 214b.
Further, the cleaning frame 214 is provided with a non-volatile drum memory 150 for storing consumable information for the cleaning unit and control information used for controlling the potential of the photosensitive drum. can communicate with the control unit 220 of
Further, the film thickness information of the drum cartridge 213 is life information of the photosensitive drum 1, which is calculated by the control unit 220 of the main body of the image forming apparatus based on the rotation time of the photosensitive drum 1 and the usage environment information of the main body. It is updated and stored in the drum memory 150 . When the life film thickness stored in the drum memory 150 is reached, the replacement life is reached. Based on this film thickness information, unit life control and charging bias correction control, which will be described later, are performed.
The life information of the photoreceptor drum 1 is not limited to film thickness information, and may be the cumulative number of rotations and cumulative rotation time of the photoreceptor drum, the cumulative number of printed surfaces, the cumulative number of printed sheets, and the motor that drives the photoreceptor drum. Indirect information such as the energization time of the battery may be used. Also included are parameters based on the remaining life such as the number of possible remaining rotations and the rotation time that decrease as the photosensitive drum is used, rather than the number of rotations that have elapsed since the start of use.

3 is an external perspective view of the developer cartridge 204. FIG.
The developer cartridge 204 has a developer frame 218 that supports various elements. The developing cartridge 204 is provided with a developing roller 17 as a developer carrier that contacts the photosensitive drum 1 and rotates in the direction of arrow D (counterclockwise) shown in FIG. 4A. The developing roller 17 is rotatably supported by the developing device frame 218 via developing bearings 219 (219R, 219L) at both ends in its longitudinal direction (rotational axis direction). Here, the developing device bearings 219 (219R, 219L) are attached to both sides of the developing device frame 218, respectively.
4A, the developer cartridge 204 has a developer storage chamber (hereinafter referred to as a toner storage chamber) 218a and a development chamber 218b in which the development roller 17 is arranged.
In the developing chamber 218b, there are provided a toner supply roller 20 as a developer supply member that rotates in the direction of arrow E in contact with the development roller 17, and a developer regulator for regulating the toner layer (developer layer) of the development roller 17. A developing blade 21 is arranged as a member. The developing blade 21 is fixed and integrated with the fixing member 22 by welding or the like.
Further, in the toner storage chamber 218a of the developing frame 218, an agitating member 23 for agitating the stored toner and conveying the toner to the toner supply roller 20 is provided.
Further, in the toner storage chamber 218a of the developing frame 218, a development memory 151 is arranged as a non-volatile first storage means for storing consumables information of the development cartridge and control information for image optimization. and can communicate with the control unit 220 on the image forming apparatus side.
Life information of the developing cartridge 204 (hereinafter referred to as development 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 development memory 151. FIG. When the number of rotations reaches the number of rotations held in the development memory 151, the exchange life is reached. Based on this development life information, correction control of charging bias, which will be described later, is performed.
The life information of the developing cartridge 204 may be the accumulated number of rotations and the accumulated rotation time of the developing roller 17 itself, or the accumulated number of printed surfaces, the accumulated number of printed sheets, the energization time of the motor that drives the developing roller 17, and other indirect information. It can be information. Also included are parameters based on the remaining life such as the number of possible remaining rotations and the rotation time that decrease as the photosensitive drum is used, rather than the number of rotations that have elapsed since the start of use.

[Control block diagram]
A control block diagram of the image forming apparatus 200 will be described.
The body controller 201 includes a control section 220 (central processing unit) as control means which is a central element for performing arithmetic processing, body memory 221 such as ROM and RAM as storage means, and input/output of information with peripheral devices. It has an input/output interface 222 and the like for performing data processing. The RAM of the main body memory 221 stores the detection results of the environment sensor 210, the calculation results, and the like, and the ROM stores control programs, previously obtained data tables such as an electrification application table storage unit, which will be described later, and the like. The control unit 220 is a control unit that 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 the transmission and reception of various electrical information signals, the timing of driving, and the like, and controls the processing of flowcharts described later.
A motor drive unit 511 indicates various motors, and is a power source for rotationally driving the polygon scanner, the photosensitive drum 1, the developing roller 17, and the like, and operates based on control signals from the control unit 220. FIG. A 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.
Also, 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 section 500 .

[Example 1]
Correction control of the charging bias of the image forming apparatus according to the first embodiment of the present invention will be described below.
There are two major factors that hinder the stability of the charging potential of the photosensitive drum 1: potential change due to contamination of the charging roller 2, and potential change due to scraping of the photosensitive drum 1 due to discharge. It is known that these factors are susceptible to the surface characteristics of the charging roller 2 used, the hardness of the photoreceptor drum 1, durability deterioration of the developing toner used, and the like. In addition, it is strongly affected by the temperature and humidity of the environment in which the image forming apparatus is used.
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 development cartridge 204 is characterized by holding information optimized in consideration of the difference in contamination caused by the development cartridge 204 with respect to the combination of the drum cartridges 213 .
This is effective when the number of combinations of drum cartridges 213 is limited to about two or three. Further, even if the life of the developing cartridge 204 is shorter than that of the drum cartridge 213 and the replacement frequency is high, the precision is improved, which is effective.
When explained in line with the control block diagram shown in FIG. 5,
Information (reference information) on the reference charging bias to be applied to the charging roller 2 corresponding to the life information of the photosensitive drum 1 is stored in advance in the main body memory 221 of the apparatus main body 200A.
A 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 .
A development memory (second storage member) 151 provided in the development cartridge (development unit) 204 holds second correction information corresponding to development life information, which is life information of the development cartridge 204 .
The control unit 220 of the main body controller 201 sequentially updates the film thickness information of the photoreceptor drum 1 by calculating it from the rotation time of the photoreceptor drum 1 and the like. A first correction value (β) corresponding to the film thickness information is acquired. The control unit 220 also calculates the developing life of the developing cartridge 204 from the rotation time of the developing roller 17, etc., and updates it successively. Obtain a corresponding second correction value (γ). Then, using the acquired first correction value (β) and second correction value (γ), the reference charging bias (α) is corrected and used as the charging application bias to be applied to the charging roller 2 .
Further, in the first embodiment, a plurality of types of the reference charging bias, the first correction information, and the second correction information are set according to the absolute moisture content, which is environmental information.

<Correction control of charging bias>
The flow of charging bias correction control in the first embodiment will be described in detail below with reference to the flowchart shown in FIG.
In the following description, the 1st (Y station) operation in the image forming apparatus 200 will be described. Since the operations of 2st to 4st are also controlled by the same flow, detailed explanation is omitted. Here, 1st to 4st mean stations where 1st is yellow, 2st is magenta, 3st is cyan, and 4st is black, and hereinafter simply referred to as 1st, 2st, 3st, and 4st.
(S101)
In S101, the main body power of the image forming apparatus 200 is turned on. As a result, the controller 220 starts charging bias control based on the control program stored in the main body memory 221 .
(S102)
In S102, the control unit 220 checks the environment sensor 210, acquires the temperature and humidity information inside the image forming apparatus 200 detected by the environment sensor 210, and obtains the absolute moisture content in the air (hereinafter referred to as moisture content) as the environment information. Calculate Further, when an output value (for example, a resistance value) corresponding to the amount of moisture in the air can be obtained directly from the environment sensor 210, the calculation of the absolute amount of moisture may be omitted. The same applies to other tables.
(S103)
In S103, the controller 220 reads information (αy) of the reference charging bias corresponding to the calculated water content from a table such as Table 16. Details of Table 16 will be described later. Note that Table 16 is stored in advance in the memory 221 of the main body controller 201, and each table described later is also assumed to be stored in advance in one of the memory 221, the drum memory 150, and the development memory 151. .
(S104)
In S<b>104 , the control unit 220 communicates with the drum memory 150 of the drum cartridge 213 to check the drum memory 150 .
(S105)
In S<b>105 , the control unit 220 communicates with the development memory 151 of the development cartridge 204 to check the development memory 151 .
Hereinafter, control differs depending on whether or not the drum memory 150 and the development memory 151 are recognized. The 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 and the drum memory 150 are recognized (mounted) 1C: Only the developing cartridge 204 and the developing memory 1D: When neither the drum memory 150 of the drum cartridge 213 nor the developing memory 151 of the developing cartridge 204 can be recognized (mounted).

<For 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, in which the correction value βy corresponding to the absolute water content and the use condition of the drum cartridge 213 is calculated from Table 2.
That is, in S<b>107 , the control unit 220 acquires film thickness information of the photosensitive drum from the drum memory 150 of the drum cartridge 213 . That is, the drum memory 150 holds film thickness information based on usage history information, and the controller 220 calculates the film thickness information based on the rotation time of the photosensitive drum 1, etc., and successively updates the film thickness information. Then, the correction table of Table 2, which is the first correction information stored in advance in the drum memory 150, is referred to, and the absolute water content calculated in S102 and the obtained drum film thickness of the photoreceptor drum 1 are matched with the first correction table. A correction value (βy) is calculated.
Details of Table 2 will be described later. Further, in S107, the control unit 220 has read the film thickness information from the drum memory 150, so the reference charging bias αy obtained based on the table of Table 16 in S102 is reacquired based on the table of Table 1.
It should be noted that, in the first embodiment, all the values held in the correction table of Table 2 are set to zero. That is, in the first embodiment, it is assumed that the influence of assembly variations during manufacturing is small, and the charging bias is not corrected according to the unique information of the drum cartridge 213 .
Note that the drum memory 150 of the drum cartridge 213 does not have color information, and the color is determined when the station to be used is installed. In the first embodiment, the body controller 201 stores in advance such that the 1st is yellow, the 2nd is magenta, the 3rd is cyan, and the 4th is black. Since the drum cartridge 213 is designed to be detachable from any station in this manner, the drum cartridge 213 can be used at any station. Note that the order of each station and the color of toner to be used is not limited to this, and color information may be freely determined for each station.
(S108, S109)
When the correction value βy is calculated, the process advances to S108 to check the development memory tag, and if there is a development memory, the process advances to S109. A second correction value (γy) is calculated.
That is, the control unit 220 acquires the development life of the development cartridge 204 from the development memory 151 of the development cartridge 204, calculates the development life from the rotation time of the development roller 17, and updates the development life. Then, the correction table of Table 3 prestored in the development memory 151 is referred to, and a yellow table is selected from a plurality of types of correction tables. Further, a second correction value (γy) is calculated that matches the water content calculated in S102, the acquired developing life, and the drum film thickness. 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 in S109. Using the second correction value γy, the charging application bias (Vpy) to be actually applied is calculated from the following calculation formula.
Charging applied bias (Vpy)=αy+βy+γy (1)
(S115)
In S115, the controller 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.

<For 1B>
(When only the drum memory of the drum cartridge is recognized (installed))
In this case, the process proceeds to S106, S107, S108, S111 and S115.
That is, steps S106 and S107 are the same as in the case of 1A, and the first correction value βy is calculated.
In this case, the second correction value (γy) in the above calculation formula (1) becomes indefinite. Therefore, the charging application bias that is actually applied is determined by the following calculation formula.
Vpy=αy+βy (2)
In the case of the first embodiment, since all the values held in the correction table shown in Table 2 are set to 0, Vpy=αy after all.
When the calculated charging application bias Vpy is determined, the control unit 220 advances to S<b>115 and 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 being αy.

<For 1C>
(Only the development cartridge, when the development memory is recognized (installed))
In this case, the process proceeds to S106, S112, S113 and S115.
That is, in S106, information on the drum memory 150 of the drum cartridge 213 cannot be obtained, so the process proceeds to S112, and when 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 usage information of the drum cartridge in Table 3 is not obtained, correction is performed only based on the usage status of the developing cartridge 204. FIG. In this case, the life (film thickness) of the photosensitive drum is used as the initial value for control.
That is, from Table 3, the life of the drum cartridge is assumed to be the initial value (for example, the drum initial film thickness is 25 μm), the second correction value γ′y corresponding to the life information of the developing cartridge 204 is calculated, and the charging application bias to be actually applied is calculated. is determined by the following formula.
Vpy=αy+γ′y (3)

<For 1D>
(When neither the drum memory of the drum cartridge nor the development memory of the development cartridge can be recognized (installed))
In this case, the process proceeds to S106, S112, S114, and S115.
That is, the step (S106) for recognizing the drum memory 150 and the step (S112) for recognizing the development memory 151 both result in (none), and the process proceeds to S114.
In this case, since neither the drum memory 150 nor the development memory 151 can be recognized, both βy and γy in the calculation formula (1) are indefinite.
Therefore, the charging application bias Vpy is controlled by the bias listed in Table 16 preset in the 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. It should be noted that the operation is commonly controlled for 1st to 4th. Since the life of the photosensitive drum 1 is uncertain, the charging bias is set to enable image formation regardless of the thickness of the drum. FIG. 12 shows the corresponding graph.

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

Table 1 is a reference charging bias table that holds reference charging bias data (charging bias reference information) based on the drum film thickness as life information of the photosensitive drum 1 and the water content as environmental information. The body memory 221 of the body controller 201 holds four tables (1st to 4st) for each color. The description of the above flowchart is an example of the 1st (Y station).
The horizontal axis of each table represents the drum film thickness, which holds three levels of 30 μm, 20 μm, and 10 μm. The film thickness times between the three levels are calculated by linear interpolation by the controller 220 of the main body controller 201 based on the charging table.
The vertical axis of each table represents the amount of water, which is the environmental information calculated by the control unit 220 from the temperature and humidity detected by the environmental sensor 210. 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 normal temperature and normal humidity (NN). Based on the water content calculated from the measured temperature and humidity, the water content is linearly interpolated and calculated. If the output value (for example, resistance value) corresponding to the amount of moisture in the air can be obtained directly from the environment sensor 210, the detected value may be used directly.
In the first embodiment, three levels of drum film thickness and three levels of water content are maintained, 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.
Graph 1 shown in FIG. 7 shows the relationship between the drum film thickness shown in Table 1, the charging bias, and the temperature and humidity.
The table of Table 1 is obtained from the results of evaluation by the inventor of the present invention.
HH (high temperature and high humidity): temperature 30°C, humidity 80% Applied charging voltage value: -1050V
NN (normal temperature and 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 dielectric constant of the photoreceptor layer changes under the influence of temperature, humidity, etc. around the photoreceptor, resulting in a change in discharge starting voltage.

Table 2 is a correction table holding the first correction information based on the drum film thickness, which is the life information of the photosensitive drum 1 held in the drum memory 150 of the drum cartridge 213, and the water content, which is the environmental information. .
The horizontal axis of the correction table represents the drum film thickness (life information of the photosensitive drum), which holds three levels of 30 μm, 20 μm, and 10 μm. The film thickness times between the three levels are calculated by linear interpolation by the controller 220 of the main body controller 201 based on the charging table.
The vertical axis of the correction table represents the amount of water, which 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, 21.0 at high temperature and high humidity (HH). 5 g, 1.1 g at low temperature and low humidity (LL), and 11.8 g at normal temperature and normal humidity (NN). Based on the water content calculated from the detected temperature and humidity, the water content is calculated by linear interpolation.
It should be noted that, in the first embodiment, all the values held in the correction table of Table 2 are set to zero. That is, in the first embodiment, it is assumed that the influence of assembly variations during manufacturing is small, and the charging bias is not corrected according to the unique information of the drum cartridge 213 .
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 is calculated based on the unique information. can be held.
FIG. 8 is a graph obtained by adding the first correction value βy to the charging reference bias value αy of Graph 1. Since the first correction value βy is 0, Graph 2 is the same as Graph 1. FIG. Note that FIG. 13 is a graph of the charging reference bias when the colors are different.

Table 3 shows the values held in the correction table of a plurality of types of second correction information held in each development memory 151 of the development cartridges 204 for four colors.
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 capacitance changes and the discharge start voltage changes. In consideration of this phenomenon, the correction table of the drum cartridge 213 for each color holds a correction value for correcting the potential drop so that a desired dark area potential can be obtained.
The correction table has 3 tables for 3 levels of water content for each color, and 12 tables for 4 colors. There are three levels of water content: 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, which is the life of the drum, and holds three levels of 30 μm, 20 μm and 10 μm. The film thickness times between the three levels are calculated by linear interpolation by the controller 220 of the main body controller 201 in the same manner as the charging table.
The vertical axis of the correction table represents the development life, which 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 drive amount (rotational speed or drive 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, the charging bias, and the temperature and humidity corresponding to Table 3.
Graphs 3-1 and 3-2 are graphs for explaining the correction tables in Table 3, and correspond to the 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, which constitutes the second correction information, is set in advance according to the drum film thickness, which is the life of the drum, and the development life (lifetime information) of each of the plurality of developing cartridges 204 to be replaced. In this example, two developer cartridges 204 are used.
Graph 3-1 shows changes in charging bias when both the drum cartridge 213 and the developing cartridge 204 are used from new.
That is, it is a graph of charging bias control when the developing cartridge 204 for yellow is fed from a drum film thickness of 25 μm to a drum film thickness of 20 μm.
As for the relationship between the development life and the drum film thickness, when the development cartridge 204 is brand new and two sheets of A4 paper are intermittently fed, the development life decreases from 100% to 0% and reaches the replacement life. 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 charging bias control when the drum cartridge 213 is replaced with a new developing cartridge 204 when the drum film thickness of the drum cartridge 213 is 20 μm, and the paper is fed until the drum film thickness is 15 μm so as to use up the developing life. be.
Both graphs 3-1 and 3-2 show a state in which the correction values of 90% and 40% shown in the correction table for yellow in Table 3 are added and corrected to an appropriate charging bias Vpy.
That is, based on the moisture information detected by the environment sensor 210, the development life, and the second correction value (γy) corresponding to the drum film thickness, the charge application bias (Vpy) is changed as shown in graphs 3-1 and 3-2. controlled.
As described above, the amount of water (temperature and humidity) in the air during use, the first correction value βy corresponding to the drum film thickness of the drum cartridge 213, the amount of water (temperature and humidity) in the air during use, and the development By combining with the second correction value γy corresponding 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 over a long period of time.

[Other embodiments]
Another embodiment of the present invention will now be described. In the following description, only differences from the first embodiment will be mainly described, and descriptions of the same configurations and functions will be omitted.
[Example 2]
First, Example 2 of the present invention will be described.
Correction control of the charging bias in the second embodiment considers four types of cartridges with different characteristics for the drum cartridge 213 . In particular, the 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 information specific to the manufacturing of the drum cartridge, and by holding the first correction value that takes into consideration the variation specific to the manufacturing of the drum cartridge, the correction accuracy can be improved compared to the first embodiment. It is higher.
That is, the drum memory 150 of the drum cartridge 213 has a correction table unique to the drum cartridge. This is the case when the correction table needs to be changed when the drum cartridge 213 is manufactured, and the drum memory 150 holds a correction value that takes into account variations in the characteristics of the drum cartridge 213 unique to the time of manufacture.
The information held by the drum memory 150 is based on data measured by various measuring instruments when the drum cartridge is manufactured. Thereby, the correction accuracy of the image forming apparatus 200 can be further improved. On the other hand, if the variation in manufacturing is limited and the influence on the correction is not large, the value to be held in the drum memory 150 should be 0. Alternatively, the drum memory 150 may not hold the manufacturing variation information, and in that case, the body controller 201 may be caused to read, for example, a default correction value of zero from the memory and use it.
As unique 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. Depending on the combination of the photosensitive drum 1 and the charging roller 2, the environmental characteristics change, and the required charging bias changes. This is because the electrostatic capacity formed by the photosensitive drum 1 and charging roller 2 changes, and each combination of the photosensitive drum 1 and charging roller 2 has a unique electrostatic capacity.
Further, since the scraping speed changes depending on the hardness of the charging roller 2 and the photosensitive drum 1, the decrease amount of the drum film thickness differs even if the number of revolutions is the same. This causes the required charging bias to change.
Therefore, the drum cartridge 213 is provided with drum memories 150 corresponding to the combinations 1-1 to 1-4.
For example, when a photosensitive drum with the combination name 1-1 is manufactured, the table of the combination name 1-1 listed in Table 5 is held in the drum memory 150. FIG. Similarly, when a drum cartridge with a combination name of 1-2 is manufactured, the table of combination 1-2 listed in Table 5 is held in the drum memory 150 . If identification at the time of manufacture is difficult, all of the combination information 1-1 to 1-4 may be held in the drum memory 150 in advance.
The combination with the drum cartridge 213 held in the development memory 151 of the development cartridge 204 holds a table of all combinations from 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 are described below.
[Regarding the photoreceptor drum 1]
The following two types of photosensitive drums 1 are used.
A type: initial drum 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 The body drum 1 has an undercoat layer formed on a support, a charge generation layer formed on the undercoat layer, and a charge transport layer formed on the charge generation layer. The charge-transporting layer preferably contains a charge-transporting substance and a resin. Examples thereof include resins having groups derived from these substances.
Examples of resins include polyester resins, polycarbonate resins, acrylic resins, and polystyrene resins. Among these, polycarbonate resins and polyester resins are preferred. A polyarylate resin is particularly preferable as the polyester resin.
The content ratio (mass ratio) of the charge transport substance and the resin is preferably 4:10 to 20:10, more preferably 5:10 to 12:10.
The charge transport layer may also contain additives such as antioxidants, ultraviolet absorbers, plasticizers, leveling agents, slipperiness agents and wear resistance improvers. Specifically, hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, silicone oils, fluororesin 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 thickness of the photosensitive drum A for carrying out the present invention was 25 μm, and that of the photosensitive drum B was 22 μm.
The charge-transporting layer can be formed by preparing a charge-transporting-layer coating solution containing each of the materials and solvents described above, forming a coating film thereon, and drying the coating film. Solvents used in the coating liquid include alcohol solvents, ketone solvents, ether solvents, ester solvents, and aromatic hydrocarbon solvents. Among these solvents, ether solvents and aromatic hydrocarbon solvents are preferred.

The photoreceptor drum used in Examples 1 and 2 was a laminated photoreceptor having a charge generation layer and a charge transport layer. You can use your body. A single-layer type photoreceptor can be formed by preparing a photosensitive layer coating solution 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 in the laminated photoreceptor. By changing the binder added to the charge transport layer, it is possible to change the hardness of the drum, and accordingly it is possible to change the scraping speed per unit number of revolutions.

[Regarding the 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
Charging the photosensitive drum 1 by the charging roller 2 means that discharge occurs from the charging roller 2 to the surface of the photosensitive drum 1 and the charge is transferred. When the potential difference between the surface of the charging roller 2 and the surface of the photosensitive drum 1 exceeds Paschen's discharge limit Vpa, discharge occurs and the charge ΔQ moves to the surface of the photosensitive drum 1 (Paschen's law). The total sum of ΔQ is the charge Q accumulated on the photosensitive drum 1 . ΔQ is represented by a relational expression between the gap (di) between the charging roller 2 and the photosensitive drum 1 and the dielectric constant (εi) of each. This dielectric constant changes depending on the hardness, resistance, and surface roughness of the charging roller 2 .
In general, the charging roller 2 should contain at least a rubber component and a conductive agent. 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, polybutadiene rubber (BR ), styrene-butadiene rubber (SBR), chlorosulfonated polyethylene, urethane rubber, SBS (styrene-butadiene-styrene-block copolymer), SEBS (styrene-ethylene-butylene-styrene-block copolymer) and other styrene-based block copolymers and silicone Rubber etc. are mentioned.
Examples of conductive agents include perchlorates such as LiClO ₄ and NaClO ₄ , ionic conductive agents such as quaternary ammonium salts, powders and fibers of metals such as aluminum, palladium, iron, copper, and silver, and carbon. Black, metal powders, metal oxides such as titanium oxide, tin oxide and zinc oxide, metal compound powders such as copper sulfide and zinc sulfide, or the surface of suitable particles such as tin oxide, antimony oxide, indium oxide, molybdenum oxide and zinc. , aluminum, gold, silver, copper, chromium, cobalt, iron, lead, platinum, rhodium by electrolysis, spray coating, mixed shaking powder, acetylene black, ketjen black, PAN (polyacrylonitrile) carbon-based carbon, pitch-based carbon powder, carbon-coated silica, carbon-coated magnetite, carbon-coated titanium oxide, carbon-coated barium sulfate, carbon whisker, graphite whisker, titanium carbide whisker, conductive potassium titanate whisker, conductive titanate Electroconductive agents such as conductive whiskers such as barium whiskers, conductive titanium oxide whiskers, and conductive zinc oxide whiskers.

These rubber components and conductive agents may be used in any combination, but epichlorohydrin rubber and ionic conductive agents are particularly preferred combinations for the purpose of reducing unevenness in the electrical resistivity of the base layer.
In this embodiment, the charging roller is manufactured using the same material, and contains fine particles as a surface layer binder and 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 spherical particles or irregularly shaped particles. Furthermore, the amount of fine particles added to the surface layer binder was 10 to 100 wt %, and only the surface roughness was changed by changing the amount of particles added. The ten-point average roughness of the surface of the charging roller 2 is preferably Rzjis=15 to 50 (.mu.m), preferably Rzjis=10 to 30 (.mu.m). 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.
Rzjis was measured in accordance with JIS-B0601-2001 using a surface roughness measuring instrument Surfcoder SE3500 manufactured by Kosaka Laboratory Ltd. In the longitudinal direction, the measurement was performed under 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.
Further, in this embodiment, a correction amount is provided for correcting a difference in dielectric constant caused by a difference in film thickness of the photosensitive drum 1 and surface roughness of the charging roller 2, but the present invention is not limited to this. , is also suitable as a correction table based on other parameters.
For example, the sensitivity, hardness, and runout of the photosensitive drum 1, and in the case of the charging roller 2, environmental characteristics of resistance, environmental characteristics of hardness, and the like.

[Control flow]
Next, the flow up to 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. If the combination is a 1-1 drum cartridge, the correction table listed in Table 5 is referred to instead of Table 2, and if the combination is a 1-2 drum cartridge, the table listed in 1-2 of Table 5. is referenced to acquire the first correction value βy.

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 sets 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 acquired from the correction table shown in Table 6.
Then, 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 development memory 151 of the development cartridges 204 for four colors.
That is, it is a contamination 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). In the second embodiment, each type of drum cartridge 213 has a table of second correction values corresponding to development life.

10A and 10B show graphs 6-1 and 6-2 for explaining the values held in the correction table of Table 6. FIG.
Graph 6-1 corresponds to the table in Table 6. That is, in Table 6, the combination of yellow station and drum cartridge for toner corresponds to (1-1) and water content LL, and the other water content (NN) and (HH) have similar tables. is provided. Further, similar tables are held for other combinations (1-2), (1-3), and (1-4).
Also in Example 2, using each specification of the drum cartridge based on Table 4, the charging bias control transition when performing intermittent endurance for two A4 sheets is shown.
Graph 6-1 shows changes in charging bias when the drum film thickness is from 25 μm to 20 μm in combination 1-1 and 1-2 specifications in Table 4. FIG. Graph 6-2 shows changes in electrification bias when the drum film thickness of the combinations 1-1 and 1-2 listed in Table 4 is used from 20 μm to 15 μm.
Both graphs 6-1 and 6-2 show a state in which a correction value is added for the development life of 90% and 40% shown in Table 6, and corrected to an appropriate charging bias Vpy.
As described above, according to the second embodiment, even if the drum cartridge 213 varies, the potential of the photosensitive drum 1 can be stably maintained for a long period of time up to the replacement life.

Subsequently, the following verification tests were conducted in order to verify the effects of Examples 1 and 2.
[Verification test]
As two cartridges used in the electrophotographic image forming apparatus shown in FIG. 1, a drum cartridge having a drum memory holding the correction information of Examples 1 and 2 and a developing cartridge having a developing memory were used. Then, it was confirmed whether or not an abnormal image was generated when the intermittent paper feed endurance test was performed.
The image forming apparatus intermittently prints 30,000 A4 sheets with a printing rate of 1% (development life from 100% to 0%) in a low-temperature, low-humidity environment (L/L: 15°C/10% RH). , image evaluation was performed. The image defect item refers to a so-called fog image in which toner is developed on a solid white image. The amount of fogging was quantified by taping a transparent tape on the photosensitive drum and then measuring the tape with a reflection densitometer (TC-6DS manufactured by Tokyo Denshoku). In this example, when the fog on the photosensitive drum was 5% or more, the fog of unacceptable image density occurred on the paper.

<Verification 1-1>
Table 7 shows the results of occurrence of image defects in the combination of the developing cartridge and the drum cartridge and charging control during sheet feeding (Examples 1 and 2, control flows 1B, 1C, 1D, 2B, 2C, and 2D).
Both the developing cartridge and the drum cartridge are used from the new state, the development life of the developing cartridge is 0%, and the thickness of the drum A is from 25 μm to 20 μm, and the thickness of the drum B is from 22 μm to 19 μm. be.
The % in the table indicates the development life % at the time when an abnormal image occurs.

<Results 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, the control flows 1B, 1C, 1D, 2B, 2C, and 2D indicate that as the endurance of development progresses, the charging potential shifts and fogging occurs. The main reasons are the difference in contamination of the charging roller and the difference in the characteristics of the drum cartridge. Examples 1 and 2
In the case of , it is possible to obtain a stable drum potential throughout the life of the developing cartridge and the drum cartridge because the control is performed in consideration of the above.

<Verification 1-2>
Verification 1-2 will now be described.
Similar to Verification 1-1, Verification 1-2 is also based on the combination of the developing cartridge and the drum cartridge, and charging control during paper passage (Example 1, Example 2, control flow 1B, 1C, 1D, 2B, 2C, 2D) to verify the result of occurrence of image defects. In this verification 1-2, a drum cartridge in the middle of use is used.
In Table 8, the developing cartridges were 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. The results are obtained by passing the developer cartridge until the development life is 0%, the drum cartridge A from the film thickness of 20 μm to 15 μm, and the drum cartridge B from the film thickness of 19 μm to 16 μm.

<Results of Verification 1-2>
As shown in Table 8, in Examples 1 and 2, appropriate charging bias control is possible without image defects. On the other hand, in the case of control flows 1B, 1C, 1D, 2B, 2C, and 2D, charging failure occurs in all cases.
It can be seen that when the durability of the photosensitive drum 1 has deteriorated, even if a new developing cartridge 204 is used, a desired charging potential cannot be obtained. As the endurance progresses in this state, a potential difference occurs even when the same toner is used for endurance. Even in this state, the embodiments 1 and 2 are controlled in consideration of the above.
A stable drum potential can be obtained.

[Example 3]
Next, Example 3 of the present invention will be described.
In the configurations of Embodiments 1 and 2 described above, if the drum cartridge 213 has a wide variety of matrices, it may be difficult in terms of storage capacity to hold all the correction controls in the drum memory 150 . In addition, when drum cartridge products are added after the image forming apparatus has been put on the market, for example, when the thickness of the drum is changed, or when charging rollers with different characteristics are sold as drum cartridges, images already on the market With the memory tag information held in the forming apparatus or developing cartridge, it may be difficult to adjust the charging bias.
A feature of the third embodiment is that the drum memory 150 of each drum cartridge 213 holds contamination prediction information for all colors in consideration of the difference in contamination caused by the toner used for each drum cartridge 213 . be.
Contamination of the charging roller 2 by the developer container will now be described.
The developing cartridge 204 in the third embodiment includes a developing blade 21 as a developer regulating member for regulating the amount of toner carried on the developing roller 17 . The developing blade 21 is made of a thin metal plate made of SUS, and is provided so that the vicinity of the tip on the free end side comes into surface contact with the outer peripheral surface of the developing roller 17 with a predetermined pressure. The toner carried on the developing roller 17 is imparted with a desired charge by triboelectrification when passing through the contact portion with the developing blade 21 and is regulated into 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 the desired electric charge, a problem of fogging occurs in which the toner is developed on a solid white background. When fogging occurs, the amount of toner collected by the cleaning blade 6 of the drum cartridge 213 increases, and the contamination of the charging roller 2 becomes worse.
When the charging roller 2 is thus contaminated, the charging ability of the charging roller 2 is lowered, the dark area potential of the photosensitive drum 1 is changed, and fogging is changed.
Further, in a full-color image forming apparatus, charging characteristics differ depending on the pigments and external additives used in the toner. For this reason, the difference in fogging occurs due to the difference in charging characteristics depending on the toner that is used.
In the two-piece cartridge, which is a feature of the present invention, especially 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 cannot be extended. However, the present invention makes it possible to solve this problem.
That is, contrary to Embodiments 1 and 2, the first correction information held in the drum memory 150 corresponds to the drum film thickness (life information) of the photosensitive drum 1 and the developing life (life information) of the developing cartridge. is pre-configured. On the other hand, the second correction information held in the development memory 151 is correction information preset according to the development life of the development unit.
As in the first and second embodiments, 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. FIG. The first correction information is preset correction information according to the drum film thickness of the photosensitive drum 1 and life information of each of the plurality of developing cartridges 204 to be replaced.

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

Hereinafter, the control differs depending on whether the drum memory and development memory are present or absent.
3A: When both the drum memory 150 of the drum cartridge 213 and the developing memory 151 of the developing cartridge 204 are recognized 3B: When only the drum cartridge 213 recognizes (mounts) the drum memory 150 3C: Only the developing cartridge 204 has the developing memory 151 Recognized (installed) 3D: Neither the drum memory 150 of the drum cartridge 213 nor the developing memory 151 of the developing cartridge 204 could be recognized (installed) <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 advances to S307 to obtain 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 ( The first correction value ηy based on the service 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 the combination 1-1 is used as the identification of the cartridges listed in Table 4, and shows correction amounts for predicting charging roller contamination based on toner and environmental information.
Although Table 10 shows the correction table for the drum cartridge combination 1-1, correction tables for the combination tables 1-2, 1-3, and 1-4 also exist separately, together with the combination information at the time of manufacture. It is held in the drum memory 150 .
(S308, 309)
In S309, the usage 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 usage state (developing life) of the developing cartridge 204 is displayed. It is calculated 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 used. This influence is held as a correction value. Note that all the holding values in Table 10 in the third embodiment are set to zero. That is, the charging bias is not corrected in accordance with the developing cartridge specific information. This is because the developer cartridge 204 is less affected by variations in assembly during manufacture.

In the third embodiment, the development memory 151 holds the correction table of Table 10 corresponding to the color of the toner used in the development cartridge 204 . 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 development memory 151 in correspondence with the color of the toner used when assembling the development cartridge.
In this way, by associating at the time of manufacture, there is no need to hold unnecessary information in the development memory 151, and it is possible to reduce the storage capacity of the memory.
In the case where the above-described correspondence at the time of manufacture is not performed, all the correction tables in Table 10 are stored in the development memory 151, so that control can be performed regardless of the color of the development cartridge assembled.
(S310, S315)
In S310, using the reference charging bias value αy calculated in S303, the first correction value (ηy) calculated in S307, and the second correction value θy calculated in S309, the actual application voltage is calculated from the following calculation formula. A charging applied bias (Vpy) to be applied is calculated.
<Calculation formula> Charge applied bias Vpy=αy+ηy+θy (4)
Next, in S<b>315 , a bias is applied to the charging roller 2 by the controller 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 life.

<For 3B>
(When only the drum memory of the drum cartridge is recognized (installed))
In this case, the process proceeds to S306, S307, S308, S311 and S315.
That is, steps S306 and S307 are the same as in the case of 3A, and the first correction value ηy is calculated.
Since the development memory information of the development cartridge cannot be obtained, θy is indefinite in the above calculation formula (4). Further, regarding ηy, the table cannot be referred to because there is no usage information of the developing cartridge. In this case, control is performed using the development life as an initial value.
Therefore, when only the drum unit recognizes the memory tag in 3B, the charging mark bias to be applied is determined by the following calculation formula (5).
Charge applied bias V'py=αy+η'y (5)
Note that, in the third embodiment, since all the values held in the table of Table 10 are set to 0, V'py=αy after all.
Next, in S<b>315 , the controller 220 controls to apply the charging application bias V′py calculated in S<b>311 to the charging roller 2 .

<For 3C>
(Only the development cartridge, when the development memory is recognized (installed))
In this case, the process proceeds to S306, S312, S313, and S315.
That is, since the information of the drum memory 150 cannot be obtained in S306, the process advances to S312 to check the development memory. After confirming the development memory, the process proceeds to S313.
Since the information of the drum memory 150 is not obtained, the first correction value ηy is indefinite in the above calculation formula (4). Further, since there is no film thickness information (lifetime information) of the photosensitive drum, Table 10 cannot be referred to. In this case, control is performed with the lifetime of the photosensitive drum as the initial value, and the charging application bias to be applied is determined by the following calculation formula (6).
Charge applied bias V'py=αy+θy (6)
Next, in S<b>315 , the controller 220 controls to apply the charging application bias V′py calculated in S<b>313 to the charging roller 2 .

<For 3D>
(When neither the drum memory of the drum cartridge nor the development memory of the development cartridge can be recognized (installed))
In this case, both the drum memory recognition step (S306) and the development memory recognition step (S312) result in (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> Charge application bias V'py is determined as indefinite.
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 S<b>315 , the controller 220 controls to apply the charging application bias V′py calculated in S<b>314 to the charging roller 2 .

[Example 4]
The electrification correction control in the fourth embodiment is characterized by using Table 11 as the developer cartridge offset table in (S307) described in the third embodiment.
That is, it is a correction value of the charging bias according to the developing cartridge-specific information, and takes into account that the durability deterioration tendency of the toner differs depending on the combination of the developing roller and the developing blade used. As described above, there are multiple factors that affect the charge of the toner, but in the present embodiment, the contact pressure of the developing blade and the surface roughness of the developing roller are dominant. Therefore, as toner contamination factors of the charging roller, 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 stored in memory tags.
Table 11 shows the combination of development key parts held in the memory tag of the development cartridge. The development memory tag holds a combination table of 3-1 to 3-4 below, each of which has its own correction value.

The details of Table 11 are as follows.
Developing roller surface roughness range C: surface roughness standard 8 to 19 (μm)
Developing roller surface roughness range D: surface roughness standard 19 to 30 (μm)
The developer roller used in the present embodiment 4 is the developing roller 17 used together with the negatively charged developer, and comprises a conductive mandrel, an elastic layer, and a conductive urethane resin layer as a surface layer. and
[Axle]
The mandrel has a cylindrical shape or a hollow cylindrical shape, and is made of the following conductive materials. metals or alloys such as aluminum, copper alloys and stainless steel; iron plated with chromium or nickel; synthetic resins having electrical conductivity. For the purpose of improving adhesion with the elastic layer provided on the outer peripheral surface of the mandrel, a known adhesive may be appropriately applied to the surface of the mandrel.
[Elastic layer]
The elastic layer contains elastic materials such as resins and rubbers. Specific examples of resins and rubbers include the following. Polyamides, nylons, polyurethane resins, urea resins, polyimides, melamine resins, fluororesins, phenolic resins, alkyd resins, polyesters, polyethers, acrylic resins, 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), fluororubber, silicone hydrides of rubber, epichlorohydrin rubber, NBR; Among these, the polyurethane resin is preferable because it has excellent triboelectrification performance to the toner, is excellent in flexibility, so that it is easy to obtain a chance of contact with the toner, and has 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 polyurethane resins include ether-based polyurethane resins, ester-based polyurethane resins, acrylic polyurethane resins, fluorine-based polyurethane resins, carbonate-based polyurethane resins, and olefin-based urethane resins.
A polyurethane resin can be obtained from a polyol and an isocyanate, and a chain extender can be used as necessary. Polyols that are raw materials for polyurethane resins include polyether polyols, polyester polyols, polycarbonate polyols, polyolefin polyols, acrylic polyols, and mixtures thereof. Examples of isocyanates, which are raw materials for polyurethane resins, include the following. 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. Examples of chain extenders that are raw materials for polyurethane resins include bifunctional low-molecular-weight diols such as ethylene glycol, 1,4-butanediol and 3-methylpentanediol, trifunctional low-molecular-weight triols such as trimethylolpropane, and these. mixtures.

When the elastic layer has a laminated structure of two or more layers, silicone rubber is preferable as a material for forming the elastic layer (lower layer) 4 on the mandrel. Silicone rubbers include polydimethylsiloxane, polymethyltrifluoropropylsiloxane, polymethylvinylsiloxane, polyphenylvinylsiloxane, and copolymers of these siloxanes. These resins and rubbers can be used singly or in combination of two or more as needed. The materials of resin and rubber can be identified by measurement using a Fourier transform infrared spectrophotometer.
If necessary, the elastic layer may further contain particles, a conductive agent, a plasticizer, a filler, an extender, a vulcanizing agent, a vulcanizing aid, a cross-linking aid, a curing inhibitor, an antioxidant, and an anti-aging agent. Various additives such as agents, processing aids, etc. may be included. These optional components can be blended in amounts that do not impair the functions of the elastic layer.
By including particles in the elastic layer, projections can be formed on the surface of the electrophotographic member. Particles that can be added to the elastic layer preferably have a volume average particle size of 1 μm or more and 30 μm or less. The particle size can be measured by observing the cross-sectional surface with a scanning electron microscope (trade name: JSM-7800FPRIME Schottky field emission scanning electron microscope, manufactured by JEOL 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 resins such as polyurethane resins, polyesters, polyethers, polyamides, acrylic resins and polycarbonates can be used. Among these, polyurethane resin particles are preferred because they are flexible and wear-resistant.
The elastic layer can be a conductive elastic layer obtained by blending the above elastic material with a conductivity-imparting agent such as an electronically conductive substance or an ionically conductive substance. Examples of electronically conductive substances include the following substances. Conductive carbon, for example, carbon black such as Ketjenblack EC, acetylene black; SAF (Super Abrasion Furnace), ISAF (Intermediate SAF), HAF (High Abrasion
Furnace), FEF (Fast Extruding Furnace), GPF (General Purpose Furnace), SRF (Semi-Reinforcing Furnace), FT (Fine Thermal), MT (Medium Thermal) carbon for rubber; ) for carbon; metals such as copper, silver, germanium and their metal oxides. Among these, conductive carbon is preferable because it is easy to control the conductivity with a small amount. Examples of ion-conductive substances include the following substances. inorganic ion-conducting substances such as sodium perchlorate, lithium perchlorate, calcium perchlorate and lithium chloride; organic ion-conducting substances such as modified aliphatic dimethylammonium ethosulfate and stearyl ammonium acetate.
Fillers include silica, quartz powder, and calcium carbonate.
Mixing of each material for the elastic layer is carried out using a dynamic mixer such as a continuous single-screw kneader, a continuous twin-screw kneader, a twin roll, a kneader mixer, and a trimix, or a static mixer such as a static mixer. be able to.

Examples of methods for forming the elastic layer on the mandrel include molding, extrusion, injection molding, and coating molding. A method of forming the first region for forming the projection will be described later. In the molding method, for example, first, pieces for holding the mandrel in the mold are fixed to both ends of a cylindrical mold, and an injection port is formed in the piece. Next, after placing the mandrel in a mold and injecting a material for the elastic layer through an injection port, the mold can be heated to a temperature at which the material hardens and demolded. In the extrusion molding method, for example, the material for the mandrel and the elastic layer are extruded together using a crosshead extruder, and the material is cured to form the elastic layer around the mandrel. .
When the elastic layer has a laminated structure of two or more layers, the surface of the elastic layer (lower layer) on the mandrel side may be surface-polished to improve adhesion, or the surface may be subjected to corona treatment, flame treatment, or 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 ten-point average roughness (JIS) Rz=8 to 30 (μm), an appropriate value can be obtained as the toner coating amount on the developing roller 17. was taken. In view of this, two levels of charge correction values are set according to 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 of the memory tag and development characteristics.

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

<Method of measuring contact pressure>
When measuring the contact pressure N (gf/mm) of the developing blade 21 against the developing roller 17, the developing device from which the developing roller 17 was removed was mounted on a dedicated measuring jig. Then, as a virtual developing roller, an aluminum sleeve having the same diameter as the developing roller 17 was prepared, and the developing blade 21 was brought into contact with it for measurement.
The length of the stylus is 50 mm, and the contact pressure of the toner supply roller 20 is calculated from the average value at two measurement points at both ends and three points at the center.
Table 12 shows the relationship between the contact pressure N (gf/mm) against the developing roller and the X value and Y value of the developing blade tip 21b in the present embodiment.

In this embodiment, the toner to be used is selected by setting the contact pressure N (gf/mm) of the developing blade against the developing roller between 2.0 (gf/mm) and 4.0 (gf/mm). Desired charge charging was possible.
In this way, by designing the surface roughness of the developing roller 17 and the contact pressure of the developing blade 21 within a range in which the toner can obtain the desired charge, the problem of fogging in which 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, even when the drum cartridge 213 has a longer service life than the developing cartridge 204, stable charging control can be performed with the two-piece cartridge, which is a feature of the present invention.
In the fourth embodiment, correction amounts are provided for toner deterioration factors caused by differences in 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, the hardness, runout, and resistance of the developing roller 17, and the surface roughness, environmental characteristics of the material, and environmental characteristics of the hardness of the developing blade 21, and the like.

Table 13 shows the correction table held in the developing memory 151 of the developing cartridge 204 in the fourth embodiment.
The correction table holds a correction value corresponding to the developing 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 each toner color.
Note that in the fourth embodiment, a table is provided for each combination of the toner color used in the developing cartridge 204 and the developing roller 17 and developing blade 21 used in the developing cartridge 204, and is stored in the developing memory 151. there is

For example, in the case of the yellow developing cartridge 204, the surface roughness of the developing roller 17 at the time of manufacture is 8 to 19 μm, and the developing blade pressure is 15 to 25, the combination 3-1 in Table 11, Yellow table. Hold. Similarly, in the case of the magenta developing cartridge 204, the surface roughness of the developing roller 17 being 19 to 30 μm, and the developing blade pressure being 25 to 40, the magenta correction table of combination 3-4 in Table 11 is developed. memory 151
to hold.
In this way, it is possible to manufacture the toner color, the roughness information of the developing roller, and the pressure information of the developing blade, which are used when the developing cartridge 204 is assembled, in association with the developing memory 151 . In this way, by associating at the time of manufacture, it is possible to reduce the memory capacity without holding unnecessary information in the development memory 151 .
In the case where the above-mentioned correspondence at the time of manufacture is not performed, all the correction tables in Table 13 are stored in the development memory 151, so that control can be performed regardless of the color of the development cartridge assembled.
By performing the above-described control, 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, the following control is performed when at least one of the drum memory and the development memory cannot be recognized, or due to the difference in memory holding mode.
With this control, it is possible to perform an image forming operation in the image forming apparatus. However, the control for stabilizing the charge potential is insufficient, and it is difficult to obtain an appropriate dark potential throughout the life. Therefore, it is necessary to be able to recognize the memory tags of both the drum cartridge and the developing cartridge.

Subsequently, in order to verify the effects of Examples 3 and 4, Verification Test 2 below was conducted.
[Verification test 2]
As in Verification Test 1, an intermittent paper feed endurance test was conducted using a two-piece cartridge used in the electrophotographic image forming apparatus shown in FIG. The presence or absence of abnormal images was confirmed when performing
The image forming apparatus intermittently prints images on 30,000 A4 sheets with a printing rate of 1% (development life from 100% to 0%) in a low-temperature, low-humidity environment (L/L: 15°C/10% RH). , image evaluation was performed. The image defect item refers to a so-called fog image in which toner is developed on a solid white image. The amount of fogging was quantified by taping the photosensitive drum with a transparent tape and measuring the tape with a reflection densitometer (TC-6DS manufactured by Tokyo Denshoku). In this example, when the fog on the photosensitive drum was 5% or more, the fog of unacceptable image density occurred on the paper.
<Verification 2-1>
Table 14 shows the results of occurrence of defective images in the combination of the developing cartridge and the drum cartridge and the charging control during paper feeding (Examples 3, 4 and conventional controls 3B, 3C, 3D, 4B, 4C, and 4D.) As the drum cartridge, the combination 1-1 described in Examples 1 and 2 was used.
Table 14 shows the results when both the developing cartridge and the drum cartridge are used from the new state, the development life of the developing cartridge is 0%, and the thickness of the drum A of the drum cartridge is from 25 μm to 20 μm. The % in the table indicates the development life % when an abnormal image occurs.

<Results of Verification 2-1>
As can be seen from Table 14, this embodiment can perform appropriate charging bias control without image defects. On the other hand, in all the conventional implementation controls, charging failure occurs.
Control in the conventional mode shows that the charge potential shifts as the endurance of development progresses, causing fogging. That is, it is largely due to the difference in contamination of the charging member and the difference in the characteristics of the drum cartridge. Since the present 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>
Similar to Verification 2-1, Verification 2-2 is also based on the combination of the developing cartridge and the drum cartridge, and charging control during paper passage (Example 3, Example 4, control flow 3B, 3C, 3D, 4B, 4C, 4D) to verify the result of occurrence of image defects. In this verification 2-2, a drum cartridge in the middle of use is used.
Table 15 shows the results when the developing cartridge is used from the new state, and the drum cartridge A is fed from a film thickness of 20 μm to 15 μm until the developing life is 0%.

<Results of Verification 2-2>
As shown in Table 15, in this example, appropriate charging bias control is possible without image defects. On the other hand, in all the conventional implementation controls, charging failure occurs.
It can be seen that when the durability of the photosensitive drum has deteriorated, a desired charging potential cannot be obtained even if a new developing cartridge is used. As the endurance progresses in this state, a potential difference occurs even when the same toner is used for endurance.
Even in this state, since the embodiments 3 and 4 are controlled in consideration of the above, it is possible to obtain a stable drum potential throughout the life of the developing machine.

As described above, the above-described embodiments of the present invention can solve the problems of the prior art. That is, in the case of storing charging control information in the memory of the apparatus main body of the image forming apparatus and performing potential stabilization control, if the specifications of the photosensitive drum, the charging roller, etc. are changed after the market is put on the market, appropriate charging control can be performed. Appropriate potential control becomes possible in order to make the memory tag of the cartridge hold the control information to change the control information.
Further, even when the photoreceptor memory and the development memory are arranged in the photoreceptor cartridge and the developing cartridge, respectively, the deterioration of the charging ability due to the contamination of the charging roller inherent in the photoreceptor cartridge is corrected based on the correction control stored in the memory. can be properly controlled.
In addition, by storing the charging roller contamination information for each toner used for all colors in the drum memory of the drum cartridge, it is possible to determine the station of the image forming apparatus to be used and the toner used in the paired developing cartridge. It can be used flexibly without depending on the color, etc., so that it can be used as a so-called universal.

1...Photoreceptor 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...Temperature Humidity sensor 220 --- main body control unit 204 --- developing cartridge 213 --- drum cartridge 217 --- developing roller

Claims (11)

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 independently attachable to and detachable from an apparatus main body of the image forming apparatus,
the apparatus main body has control means for controlling the charging bias applied to the charging member;
The image carrier unit has a first storage member that holds first correction information used for correcting the charging bias according to life information of the image carrier,
The developing unit has a second storage member holding second correction information used for correcting the charging bias according to life information of the developing unit,
The apparatus main body holds a reference charging bias according to reference information serving as a reference of the charging bias when the charging bias is corrected based on the first correction information and the second correction information. having a storage unit,
The control means acquires the first correction information stored in the first storage member, acquires the second correction information from the second storage member, and stores the acquired first correction information and the second correction. An image forming apparatus, wherein a correction amount of the charging bias calculated from information is acquired, and control for correcting the charging bias is executed based on the reference charging bias and the correction amount of the charging bias. 2. An image forming apparatus according to claim 1, wherein said first correction information corresponds to a characteristic charging characteristic of said image carrier unit. 3. The image forming apparatus according to claim 2, wherein the charging characteristic specific to said image carrier unit corresponds to a combination of the type of said image carrier and the type of said charging member. When either the first correction information or the second correction information cannot be obtained, the control means obtains from the obtained correction information the first correction information or the second correction information. 4. The image forming apparatus according to claim 1, wherein control is performed so as to correct the charging bias based on the correction amount. 2. The image forming apparatus according to claim 1, 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 main 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 acquires the first correction information according to the acquired environment information. 6. The image forming apparatus according to claim 5, wherein the reference information of the charging bias is corrected using the second correction information and the second correction information. 2. The image forming apparatus according to claim 1, wherein a plurality of types of the charging bias reference information, the first correction information, and the second correction information are provided according to the color of the developer. 8. The image forming apparatus according to claim 1, wherein the first storage member and the second storage member have the same storage capacity. The control means adds a first correction amount, which is the charging bias correction amount in the first correction information, to a second correction amount, which is the charging bias correction amount in the second correction information. 2. The image forming apparatus according to claim 1, wherein a correction amount of said charging bias is determined. The control means controls the charging bias correction amount and the reference charging bias obtained by adding the first correction amount and the second correction amount calculated from the first correction information and the second correction information. 10. The image forming apparatus according to claim 9, wherein control is performed to correct the charging bias by adding . The control means selects the first correction amount and the second correction amount corresponding to the first correction information and the second correction information from tables stored in the first storage member and the second storage member. 11. The image forming apparatus according to claim 10, wherein the image forming apparatus is controlled so as to

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