JP2002296880A - Image forming apparatus and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep the electrifying performance of an image forming apparatus adopting a contact electrifying means preferable for long-time use. SOLUTION: A process cartridge including an image carrier 1, a contact electrifying member 8 to the image carrier 1, a detection means 20 which detects the residual amount of developer, and a storage means 60 can be attached to and detached from the image forming apparatus, and the image forming apparatus is provided with a first driving means 600 which rotationally drives the image carrier 1, a second driving means 501 which rotationally drives the contact electrifying member 8, and control means 602, 502, and 651 which control the driving speeds of the first and the second driving means 600 and 501, and the control means control the driving speed of the second driving means 501 on the basis of the rotational frequency of the second driving means 501, which is stored in the storage means 60.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electrophotographic image forming apparatus employing a contact charging means, and a process cartridge detachable from the image forming apparatus.

Here, the electrophotographic image forming apparatus forms an image on a recording medium using an electrophotographic image forming method. Examples of the electrophotographic image forming apparatus include, for example, an electrophotographic copying machine, an electrophotographic printer (for example, a laser beam printer, an LED printer, and the like), a facsimile machine, a word processor, and the like.

A process cartridge is a cartridge in which a charging unit, a developing unit, and an electrophotographic photosensitive drum are integrally formed into a cartridge, and this cartridge is detachable from an electrophotographic image forming apparatus main body. as well as,
The charging means and the electrophotographic photosensitive drum are integrally formed as a cartridge so as to be detachable from the electrophotographic image forming apparatus main body.

[0004]

2. Description of the Related Art Conventionally, in an image forming apparatus using an electrophotographic image forming process, an electrophotographic photosensitive member and process means acting on the electrophotographic photosensitive member are integrally formed into a cartridge, and this cartridge is used as an image forming apparatus. A process cartridge system which can be attached to and detached from is used.

According to this process cartridge system,
Since the maintenance of the apparatus can be performed by the user himself without relying on a service person, the operability can be remarkably improved. For this reason, the process cartridge system is widely used in image forming apparatuses.

In such an image forming apparatus and a process cartridge, when an electrostatic latent image is formed on an image carrier, a charging step for charging the image carrier to a uniform potential is required. As a device, a corona charging device (non-contact with an image carrier) has been widely used. However, the corona charging device has problems such as generation of ozone and application of a high voltage of about 10 kV between the charging device and the image carrier.

As charging means for solving these problems,
In recent years, a so-called contact charging device that uniformly charges an image carrier by applying a voltage to a charging member that directly contacts the image carrier has been proposed and put into practical use.

A typical example of the contact charging device is a roller charging device, in which a medium resistance layer is provided on the surface of a conductive base roller. To rotate. A predetermined voltage is applied between the roller and the image carrier by a power supply, whereby the image carrier is charged to a uniform potential.

Here, there are two types of voltage application: (1) a method of applying only a DC voltage, and (2) a method of applying a voltage obtained by superimposing an AC voltage on a DC voltage.

In the case of (1), for example, it is necessary to apply a voltage of about -1300 V in order to bring the potential on the image carrier to -600 V, and in the case of (2), the DC voltage is -600 V By applying a superimposed AC voltage of 1500 Vpp or more, the potential on the image carrier is similarly lowered by -6.
00V.

The charging mechanism in this case follows Paschen's law in any case. At a certain distance between the roller and the image carrier, a discharge phenomenon occurs in a region satisfying Paschen's law, and This is to charge the carrier.

However, as can be seen from the charging mechanism described above, such a contact charging device performs the same operation as the corona charging device described above in a small space, and is compared with the corona charging device. Ozone is still generated, although it is greatly reduced. This ozone produces nitrogen oxide and, when adhered to the image carrier, has a low resistance, which causes image failure due to poor charging.

Therefore, a charging process that does not have the above-described problem of ozone generation and that can further reduce the voltage applied to the charging device has been proposed in Japanese Patent Application Laid-Open No. Hei 6-3921.

A feature of this charging process is that the surface potential of the image carrier can be made substantially the same as the voltage applied to the charging device. This is because the surface of the image carrier that is in contact with the charging member can be used without using a discharge phenomenon. This is made possible by injecting charges into the image carrier by exchanging charges directly with the image carrier.

As a charging device for realizing the above injection charging process, a sponge roller charging device will be described here. In this type, relatively low-resistance particles (conductive particles) referred to as charge-promoting particles are attached to an empty portion on the surface of a charging sponge roller that comes into contact with the image carrier.

Regarding the contact charging (direct injection charging) using the charge promoting particles, JP-A-10-307454, JP-A-10-307455, JP-A-10-307456, JP-A-10-307457, JP-A-10-307458 and It is disclosed in, for example, Japanese Unexamined Patent Publication No. Hei 10-307459.

In this system, a DC voltage of -600 V is applied to the charging sponge roller from a power supply. Therefore, the portion of the image carrier that is in contact with the charging sponge roller tends to have the same potential. At this time, if the charge is injected from the charging sponge roller into the image carrier beyond the energy barrier on the surface of the image carrier, the image carrier is charged, and the energy barrier cannot be exceeded. If the charge moves again from the image carrier to the charging sponge roller when the body separates, no charging occurs.

While this phenomenon is largely due to the surface energy barrier and charge holding ability of the image carrier,
When considered as a competitive reaction, the frequency of the chance that the charged sponge roller contacts the image carrier becomes important.

In order to increase the frequency, the adhesion between the charging sponge roller and the image carrier is improved by adhering the charge promoting particles to the surface of the charging sponge roller, and the rotation direction of the charging sponge roller is changed to the image carrier. (The contact surfaces of the image carrier and the charging sponge roller move in opposite directions while rubbing each other) to increase the relative speed,
It is effective to increase the number of times of contact with the image carrier per time.

By doing so, the surface potential of the image bearing member becomes substantially the same as -600 V applied to the charging sponge roller, and uniform charging can be performed even on microscopic portions without uneven charging.

The charge-promoting particles have a charge polarity opposite to that of the developer, remain on the image carrier without being transferred to transfer paper by a transfer device, and are collected on a charging sponge roller. , Always get a new injection site.

In this type, after the transfer of the image on the image carrier, the developer remaining after the transfer passes through the space between the charge accelerating particles undergoing the charging step and the image carrier, and remains the same as the image carrier. Since the charge is injected into the developing device, it is possible to have an appropriate charge, so that the toner is collected by the developing device without passing through the region where the developing process is performed. Therefore, an electrophotographic process without a cleaner can be realized.

[0023]

However, in the above-described injection charging method, the charging performance is deteriorated due to long-term use,
More specifically, a decrease in charging uniformity may occur. This is mainly because the contact area between the charge accelerating particles and the image carrier is reduced by the developer, which is an insulator slightly accumulated on the charging sponge roller.

The present invention has been made in view of such circumstances, and a purpose thereof is to provide an image forming apparatus and a process cartridge which employ the above-described contact charging means so that the charging performance can be improved over a long period of use. Is to maintain.

[0025]

The present invention provides an image forming apparatus and a process cartridge characterized by the following means.

(1) an image carrier, a charging member in contact with the image carrier, and a detecting means for detecting the remaining amount of the developer;
An image forming apparatus including a storage unit and a process cartridge including a storage unit, wherein the first driving unit is configured to rotationally drive the image carrier, the second driving unit is configured to rotationally drive the contact charging member, Control means for controlling the drive speed of the first drive means and the second drive means, wherein the control means controls the second drive based on the rotation speed of the second drive means stored in the storage means. An image forming apparatus for controlling a driving speed of the means.

(2) The image forming apparatus according to (1),
When the remaining amount of developer or the amount of consumed developer detected by the detection unit reaches a predetermined value, the control unit drives the second driving unit based on the number of rotations stored in the storage unit. An image forming apparatus, wherein the speed is changed.

(3) The image forming apparatus according to the above (1),
The image forming apparatus according to claim 1, wherein the control unit controls the rotation speed of the second driving unit to increase stepwise as the developer consumption increases or the developer remaining amount decreases. .

(4) The image forming apparatus according to (1),
An image forming apparatus comprising: developing means for developing a latent image formed on the image carrier with a developer.

(5) The image forming apparatus according to (4),
The developer of the developing unit includes toner and conductive charge-promoting particles, and the contact charging member is a plastic charging member that forms a nip with the image carrier, and is disposed between the image carrier and the image carrier. An image forming apparatus, wherein a voltage is applied in a state where the charging promoting member is interposed.

(6) The image forming apparatus according to (1),
The image forming apparatus is characterized in that the image carrier is a photoconductor, and the contact charging member is a charging roller.

(7) The image forming apparatus of (1),
An image forming apparatus, wherein a program for controlling a driving speed of the second driving unit is stored in the storage unit.

(8) an image carrier, a charging member in contact with the image carrier, and a detecting means for detecting the remaining amount of the developer;
An image forming apparatus including a storage unit and a process cartridge including a storage unit, wherein the first driving unit is configured to rotationally drive the image carrier, the second driving unit is configured to rotationally drive the contact charging member, Control means for controlling driving speeds of the first driving means and the second driving means and calculating a cumulative rubbing distance between the image carrier and the contact charging member; One or more rotation speeds of the second drive unit corresponding to the friction distance are stored, and the control unit controls the drive speed of the second drive unit based on the rotation speed stored in the storage unit. An image forming apparatus.

(9) The image forming apparatus according to (8),
When the remaining amount of developer or the amount of consumed developer detected by the detection unit reaches each of one or more predetermined values, the control unit performs the control based on the number of rotations stored in the storage unit. An image forming apparatus, wherein a driving speed of a second driving unit is changed.

(10) The image forming apparatus according to (8), wherein the control means increases the rotational speed of the second driving means as the developer consumption increases or the developer remaining amount decreases. An image forming apparatus characterized in that control is performed so as to increase stepwise.

(11) The image forming apparatus according to (8), further comprising a developing means for developing a latent image formed on the image carrier with a developer.

(12) In the image forming apparatus of (11), the developer of the developing means includes toner and conductive charge-promoting particles, and the contact charging member has a nip portion with the image carrier. An image forming apparatus, which is a plastic charging member to be formed, wherein a voltage is applied in a state where the charging promotion member is interposed between the charging member and the image carrier.

(13) The image forming apparatus according to (8), wherein the image carrier is a photosensitive member, and the contact charging member is a charging roller.

(14) The image forming apparatus according to (8), wherein a program for controlling a driving speed of the second driving unit is stored in the storage unit.

(15) An image forming apparatus in which a process cartridge including an image carrier, a charging member in contact with the image carrier, a detector for detecting the remaining amount of the developer, and a memory is detachable. A first driving unit for rotationally driving the image carrier, a second driving unit for rotationally driving the contact charging member, and controlling a driving speed of the first driving unit and the second driving unit; A cumulative rubbing distance between the image carrier and the contact charging member is calculated, and two or more of the calculated value and the remaining amount of developer or the amount of developer consumption detected by the detection unit are written into the storage unit. Control means for controlling the rotation of the second drive means based on two or more of the accumulated rubbing distances stored in the storage means and the remaining amount of developer or the amount of developer consumption. Calculate the number and calculate the value An image forming apparatus controls said second drive means on the basis of.

(16) The image forming apparatus according to (15), wherein the number of revolutions calculated by the control means is written in the storage means.

(17) The image forming apparatus according to (15), wherein the control means reaches the developer amount remaining amount or the developer consumption amount detected by the detection unit, each of which reaches one or more predetermined values. An image forming apparatus configured to change a driving speed of the second driving unit based on the number of rotations stored in the storage unit when the operation is performed.

(18) The image forming apparatus according to (15), wherein the control means controls the rotation speed of the second drive means as the developer consumption increases or the developer remaining amount decreases. An image forming apparatus characterized in that the image forming apparatus is controlled so as to increase step by step.

(19) The image forming apparatus according to the above (15), further comprising a developing means for developing a latent image formed on the image carrier with a developer.

(20) In the image forming apparatus of the above (19), the developer of the developing means includes a toner and conductive charge-promoting particles, and the contact charging member has a nip portion with the image carrier. An image forming apparatus, which is a plastic charging member to be formed, wherein a voltage is applied in a state where the charging promotion member is interposed between the charging member and the image carrier.

(21) The image forming apparatus according to (15), wherein the image carrier is a photosensitive member, and the contact charging member is a charging roller.

(22) The image forming apparatus according to (15), wherein the storage means stores a program for controlling the driving speed of the second driving means.

(23) In the image forming apparatus according to (15), when the rotation speed calculated by the control means is smaller than a minimum value, the rotation speed is replaced with a minimum value.
The image forming apparatus according to claim 1, wherein when the rotation speed is larger than a maximum value, the rotation speed is replaced with a maximum value.

(24) An image forming apparatus in which a process cartridge including an image carrier, a contact charging member for the image carrier, a detector for detecting an amount of developer, and a memory is detachably mountable. A first driving unit for rotationally driving the carrier, a second driving unit for rotationally driving the contact charging member, and a control unit for controlling the rotation of the first driving unit at a plurality of driving speeds. The control means controls the second drive so that when the drive speed of the first drive means is changed, the ratio of the drive speed of the first drive means to the drive speed of the second drive means is the same. An image forming apparatus for controlling a driving speed of the means.

(25) First driving means for rotating and driving the image carrier, second driving means for rotating and driving the contact charging member with respect to the image carrier, the first driving means and the second driving means A process cartridge detachable from an image forming apparatus having a control unit for controlling a driving speed of a driving unit, wherein the image carrier, a contact charging member for the image carrier, and a detection unit for detecting a remaining amount of a developer. Means, said second
A storage unit for storing a rotation speed for changing a driving speed of the driving unit.

(26) The process cartridge according to (25), wherein the drive speed of the second drive means is reduced when the remaining amount of developer or the consumed amount of developer detected by the detection means reaches a predetermined value. A process cartridge wherein the number of revolutions is read from the storage means for changing.

(27) The process cartridge according to the above (25), further comprising a developing means for developing a latent image formed on the image carrier with a developer.

(28) The process cartridge according to (27), wherein the developer of the developing means includes a toner and conductive charge-promoting particles, and the contact charging member forms a nip with the image carrier. A process cartridge, wherein a voltage is applied in a state where the charging promoting member is interposed between the charging member and the image bearing member.

(29) The process cartridge according to (25), wherein the image carrier is a photosensitive member, and the contact charging member is a charging roller.

(30) The process cartridge according to (25), wherein the storage means is a rewritable nonvolatile storage medium.

(31) First driving means for rotating and driving the image carrier, second driving means for rotating and driving the contact charging member with respect to the image carrier, the first driving means and the second driving means A cartridge that is detachable from an image forming apparatus having a control unit that controls a driving speed of a driving unit and calculates a cumulative rubbing distance between the image bearing member and the contact charging member; A contact charging member for the image carrier, a detecting unit for detecting a remaining amount of the developer, and one or more rotation speeds corresponding to the cumulative rubbing distance for controlling a driving speed of the second driving unit are stored. A process cartridge having storage means.

(32) The cartridge according to (31), wherein when the remaining amount of developer or the amount of consumed developer detected by the detecting means reaches one or more predetermined values, the second cartridge is used.
The process cartridge according to claim 1, wherein the number of rotations is read from the storage unit in order to change a driving speed of the driving unit.

(33) The process cartridge according to (31), further comprising a developing means for developing a latent image formed on the image carrier with a developer.

(34) The process cartridge according to (33), wherein the developer of the developing means includes a toner and conductive charge-promoting particles, and the contact charging member forms a nip with the image carrier. A process cartridge, wherein a voltage is applied in a state where the charging promoting member is interposed between the charging member and the image bearing member.

(35) The process cartridge according to (31), wherein the image carrier is a photosensitive member, and the contact charging member is a charging roller.

(36) First driving means for rotating and driving the image carrier, second driving means for rotating and driving the contact charging member with respect to the image carrier, the first driving means and the second driving means A cartridge that is detachable from an image forming apparatus having a control unit that controls a driving speed of a driving unit and calculates a cumulative rubbing distance between the image bearing member and the contact charging member; A contact charging member for the image carrier; a detection unit for detecting a remaining amount of the developer; and a storage unit for storing two or more of the accumulated rubbing distance and the remaining amount of the developer or the amount of consumed developer. A process cartridge characterized by the above-mentioned.

(37) The cartridge according to (36), wherein when the remaining amount of developer or the amount of consumed developer detected by the detecting means reaches one or more predetermined values,
A process cartridge, wherein a rotation speed of the second drive unit for changing a drive speed of the second drive unit is written in the storage unit.

(38) The process cartridge according to (36), further comprising a developing means for developing a latent image formed on the image carrier with a developer.

(39) The process cartridge according to (38), wherein the developer of the developing means contains toner and conductive charge-promoting particles, and the contact charging member forms a nip with the image carrier. A process cartridge, wherein a voltage is applied in a state where the charging promoting member is interposed between the charging member and the image bearing member.

(40) The process cartridge according to (31), wherein the image carrier is a photosensitive member, and the contact charging member is a charging roller.

(41) An image carrier, a charging member in contact with the image carrier, a storage means for storing data corresponding to the remaining amount of the developer, and a storage means for storing the data in the storage means. An image forming apparatus comprising: an image carrier; and control means for variably controlling a peripheral speed of the contact charging member.

(42) An image carrier, a contact charging member for the image carrier, storage means for storing data corresponding to the amount of developer used, and cumulative sliding of the image carrier and the contact charging member. An image forming apparatus comprising: a control unit that calculates a friction distance and variably controls a peripheral speed of the image carrier and the contact charging member according to the calculated value and data stored in the storage unit.

[0068]

(First Embodiment) FIG. 1 is a schematic sectional view showing the internal structure of an embodiment of an image forming apparatus according to the present invention.
FIG. 2 is an external perspective model view.

(1) Image Forming Apparatus A and Process Cartridge B The image forming apparatus of this embodiment is a laser beam printer A as an electrophotographic image forming apparatus, which is of a process cartridge detachable type. B is a process cartridge.

The laser beam printer A forms a toner image on a drum-shaped electrophotographic photosensitive member (hereinafter, referred to as a photosensitive drum) 7 as an image carrier by an electrophotographic image forming process, and stores the toner image on a recording medium. (For example, recording paper, OHP sheet, cloth, etc.) 2 to form an image.

More specifically, the photosensitive drum 7 is charged by the charging means 8, and then a latent image is formed on the photosensitive drum 7 from the optical means 1 according to the image information. This latent image is developed by the developing means 9 to form a toner image.

In synchronization with the formation of the toner image, the recording medium 2 set in the sheet cassette 3a is reversely transferred by the pickup roller 3b, the conveying roller pairs 3c and 3d, and the registration roller pair 3e. Next, the toner image formed on the photosensitive drum 7 is transferred to the recording medium 2 by applying a voltage to the transfer roller 4 as a transfer unit.

Then, the recording medium 2 to which the toner image has been transferred
Is transported to the fixing unit 5 by the transport guide 3f. The fixing unit 5 includes a driving roller 5c and a fixing roller 5b including a heater 5a. Then, heat and pressure are applied to the passing recording medium 2 to fix the transferred toner image.

The recording medium 2 is discharged to a pair of discharge rollers 3g and 3g.
h, 3i, and the discharge tray 6 through the reversing path 3j.
Discharge to The discharge tray 6 is provided on the upper surface of the apparatus main body 14 of the printer A. Swingable flapper 3
k, and the reverse path 3j is driven by the discharge roller pair 3m.
The recording medium 2 can be ejected without passing through.

In this embodiment, the pickup roller 3b, the conveying roller pair 3c, 3d, the registration roller pair 3e, the conveying guide 3f, the discharging roller pair 3g, 3h,
3i, reversing path 3j, flapper 3k, discharge roller pair 3m
The transport means 3 is constituted by the above.

The process cartridge B detachable from the printer main body includes a photosensitive drum 7 and at least charging means 8
It is provided with. As other process means included in the process cartridge B, for example, there is a developing means 9 for developing a latent image formed on the photosensitive drum 7 and the like. The process cartridge B of the present embodiment includes a photosensitive drum 7
, A charging roller 8 serving as a charging unit, and a developing unit 9 are integrally formed as a cartridge.

The photosensitive drum 7, which is an electrophotographic photosensitive member having a photosensitive layer 7e (FIG. 6), is rotated, and a voltage is applied to a charging roller 8, which is a charging means, to uniformly charge the surface of the photosensitive drum 7. I do. Next, a laser beam corresponding to the image information from the optical system 1 is irradiated onto the photosensitive drum 7 through the exposure opening 1e to form a latent image. Then, the latent image is developed by developing means 9 using toner.

The charging roller 8 is provided in contact with the photosensitive drum 7, and charges the photosensitive drum 7. The charging roller 8 is provided with a predetermined pressing force, a nip portion is formed on the contact surface with the photosensitive drum 7, and the contact surface is opposite to the photosensitive drum 7 by a charging roller driving unit described later. Rotate to move in the direction. That is, the charging roller 8 and the photosensitive drum 7 rotate in the same direction (clockwise in this embodiment). The configuration for supporting and driving the charging roller 8 and the photosensitive drum 7 will be described later.

The optical system 1 has a laser diode 1a, a polygon mirror 1b, a lens 1c, and a reflection mirror 1d.

The developing means 9 supplies toner to the developing area of the photosensitive drum 7 to develop the latent image formed on the photosensitive drum 7. The developing means 9 in this embodiment is a reversal developing device using a magnetic one-component insulating toner (negative toner), and sends out the toner in the toner container 11A to the developing roller 9c by the rotation of the toner sending member 9b, and fixes the fixed magnet. The built-in developing roller 9c is rotated, and the developing blade 9 is rotated.
A toner layer provided with a triboelectric charge by d is formed on the surface of the developing roller 9c, and the toner is supplied to the developing area of the photosensitive drum 7.

The toner is transferred to the photosensitive drum 7 in accordance with the latent image to form a toner image and visualize the toner image.

The developing blade 9d regulates the amount of toner on the peripheral surface of the developing roller 9c and applies a triboelectric charge.

A toner stirring member 9e (FIG. 3) for circulating toner in the developing chamber is rotatably mounted near the developing roller 9c.

The toner is prepared by mixing a binder resin, magnetic particles, and a charge controlling agent, and performing kneading, pulverizing, and classifying processes, and adding thereto charge accelerating particles and a fluidizing agent as external additives. It was produced by

To transfer the toner image from the photosensitive drum 7 to the recording medium 2, a voltage having a polarity opposite to that of the toner image is applied to the transfer roller 4 to record the toner image formed on the photosensitive drum 7. Transfer to the medium 2.

The printer of this embodiment is cleaner-less, and the transfer residual toner remaining on the surface of the photosensitive drum 7 after the transfer of the toner image onto the recording medium 2 is not removed by the cleaner. With the rotation, the toner reaches the developing means 9 via the charging means 8 and is collected at the same time as the development (so-called toner recycling process).

FIG. 3 is a cross-sectional model view showing the internal structure of the process cartridge B, FIG. 4 is a perspective view of the external appearance, and FIG. 5 is a perspective view of the external appearance with the process cartridge turned over and the drum shutter member opened. It is.

The process cartridge B is composed of a toner frame 11 having a toner container (toner storage section) 11A for storing toner and a developing frame 12 for holding developing means 9 such as a developing roller 9c. A drum frame 13 to which the body drum 7 and the charging roller 8 are attached is rotatably connected via an arm 19 and a shaft 22 to form a cartridge.

The process cartridge B includes:
An exposure opening 1e for irradiating the photosensitive drum 7 with light corresponding to image information and a transfer opening 13n for facing the photosensitive drum 7 to the recording medium 2 or the transfer roller 4 are provided. Specifically, the exposure opening 1e is provided in the drum frame 13, and the transfer opening 13n is provided in the developing frame 1
2 and the drum frame 13.

Further, when the process cartridge B is detached from the printer main body 14, the transfer opening 13n
A drum shutter member 18 that covers the photosensitive drum 7 and protects the photosensitive drum 7 from being exposed to light for a long time or from contact with foreign matter is rotatably provided on the developing frame 12. FIG. 3 shows a state in which the transfer opening 13 n is covered with the drum shutter member 18.

The process cartridge B can be attached to and detached from the printer main body 14 by an operator. The cartridge attaching / detaching means moves the opening / closing member 35 of the printer main body 14 around the shaft 35a as shown by a two-dot chain line in FIG. Open, a space for a cartridge mounting portion in the printer main body 14 appears, and a cartridge mounting guide member (not shown) is disposed on the left and right sides thereof.
a and 18b (FIGS. 4 and 5) are fitted and guided by the mounting guide member, and the process cartridge B
4.

The drum shutter member 18 automatically opens and closes in conjunction with the mounting and dismounting operation of the process cartridge B. That is, when the process cartridge B is mounted on the printer main body 14, the drum shutter member 18 is released from the transfer opening 13n and held in an open state as shown in FIG.
When the transfer opening 13n is taken out from the transfer opening 13, the transfer opening 13n is moved to a position where the transfer opening 13n is covered and closed as shown by a solid line in FIG.

The process cartridge B is in the printer body 1
4, the printer body 14
It is in a predetermined coupling state mechanically and electrically with the side.

Next, the configuration of the main part according to this embodiment will be described in detail.

First, the configuration of the charging means will be described.
The charging process according to the present embodiment is performed by an injection charging device in which the charging roller 8 is covered with the charging promoting particles.

The charging roller 8 is an elastic roller having conductivity. A medium resistance layer made of a rubber or foam plastic member (flexible member, elastic member) is formed on a metal cored bar in the shape of a roller. ing. The medium resistance layer is formed of a resin (for example, urethane), conductive particles (for example, carbon black), a sulfide agent, a foaming agent, and the like.

The charge-promoting particles are conductive zinc oxide particles having an average diameter of 3 μm including the secondary aggregate and a specific resistance of 10 ⁶ Ω · cm. Is the positive polarity. As the material of the charge accelerating particles, various conductive particles such as conductive inorganic particles such as other metal compounds and mixtures with organic substances can be used.

Next, the support, drive configuration, and control system of the photosensitive drum 1 and the charging roller 8 will be described with reference to FIGS. FIG. 6 is a schematic explanatory diagram showing a supporting configuration and a driving configuration of the charging roller 8 and the photosensitive drum 7, and FIG. 7 is a schematic diagram of a control system.

At both ends of the metal core 8a of the charging roller 8,
A cylindrical abutting member 200 for keeping the distance between the photosensitive drum 7 and the core bar 8a constant is provided rotatably. The abutment member 200 is set to have an outer diameter smaller than the outer diameter of the charging roller 8, and in this embodiment, is set to be smaller by about 0.2 mm in radius.

The charging roller 8 is rotatably supported by a bearing 201 provided on the drum frame 13 so as to swing.

More specifically, a bearing 201 made of a slidable resin (for example, polyacetal) or the like is attached to a guide portion 13a (FIG. 3) provided on the drum frame 13. Further, the charging roller 8 is attached to the bearing 201. A compression coil spring 202 for applying an urging force in a direction in which the photosensitive drum 7 is pressed against the photosensitive drum 7 is provided.

On the other hand, a coupling member 203 is provided at one end in the longitudinal direction of the metal core 8a of the charging roller 8 so as not to rotate with respect to the metal core 8a. The coupling member 2
03 denotes a second drive transmission shaft 5 provided on the printer main body 14.
00 and the driving force is transmitted.

The second drive transmission shaft 500 is configured to be rotatable in the circumferential direction and swingable in the axial direction in conjunction with the opening / closing operation of the printer body opening / closing member 35 (FIG. 1). When the cartridge B is mounted on the printer main body 14 and the opening / closing member 35 is closed, the second drive transmission shaft 500 protrudes, is coupled with the coupling member 203, and
When it is opened, it retreats in the direction opposite to the protruding direction, the connection with the coupling member 203 is released, and the process cartridge B can be taken out. As a method of linking the second drive transmission shaft 500 with the opening / closing operation of the opening / closing member 35, a lever or the like may be provided on the opening / closing member 35.

The second drive transmission shaft 500 receives a drive force from a second drive motor (second drive means) 501 as a drive source via gears (not shown). Further, the second drive motor 501 is connected to a second drive control means (motor driver) 502, and is provided with an arithmetic control means (CPU)
The rotation speed of the charging roller 8 is controlled based on the information from 651 (FIG. 7).

Next, the photosensitive drum unit U and the drive configuration of the photosensitive drum unit U will be described. The photosensitive drum 7 according to the present embodiment is formed by applying an organic photoconductor layer 7e to the outside of an aluminum cylinder, and a drum frame 13 is provided.
It is supported rotatably.

A charging roller 8 for uniformly charging the surface of the photosensitive drum 7 is arranged on the periphery of the photosensitive drum 7, and a first driving motor (first driving means) provided in the printer main body 14 is provided. ) 600 driving force to the photosensitive drum 7
Further, as described above, the second drive motor (second drive means) 50
By transmitting the first driving force to the charging roller 8, the photosensitive drum 7 and the charging roller 8 are each rotated according to the image forming operation.

The first drive motor 600 is connected to the first drive control means (motor driver) 602.

At one end of the photosensitive drum 7 in the axial direction,
The drum flange 36 is fixed. Photoconductor drum 7
The drum flange 36 is fitted with a fitting outer diameter portion 36b provided on the drum flange 36 to the inner diameter 7d of the photosensitive drum 7, and the end of the photosensitive drum 7 is provided in a concave portion (not shown) provided on the drum flange 36. It is fixed by bending inside.

A gear portion 40 is provided on the drum flange 36. The gear portion 40 meshes with a developing roller gear (not shown) for rotating the developing roller 9c provided on the developing roller 9c. The driving force is transmitted to 9c.

The shaft portion 3 is attached to the drum flange 36.
6a is provided, is fitted to the fitting inner diameter portion 300a of the bearing member 300 provided on the drum frame 13, and is rotatably supported by the shaft.

Further, the drum flange 36 is formed with a convex portion 36d as a driving force receiving portion for receiving a driving force from the printer main body 14. The convex portion 36d is fitted with a concave portion 601a of a first drive transmission shaft 601 provided on the printer main body 14 to transmit a driving force.

The first drive transmission shaft 601 is connected to the printer body opening / closing member 3 similarly to the second drive transmission shaft 500 described above.
5 (Fig. 1) in conjunction with the opening and closing operation, can rotate in the circumferential direction,
When the process cartridge B is mounted on the printer main body 14 and the opening / closing member 35 is closed, the first drive transmission shaft 601 protrudes, is coupled with the convex portion 36d, and opens the opening / closing member 35. And in the direction opposite to the protruding direction, the connection with the convex portion 36d is released, and the process cartridge B can be taken out.

The first drive transmission shaft 601 receives a drive force from a first drive motor 600 as a drive source via gears (not shown).

A drum flange 37 is fixed to the other end of the photosensitive drum 7 in the axial direction.

The fixing method is as follows.
Similarly, the fitting outer diameter portion 37b provided on the drum flange 37 is fitted into the inner diameter 7d of the photosensitive drum 7, and the end of the photosensitive drum 7 is provided in the concave portion (not shown) provided on the drum flange 37. It is fixed by bending it inside.

A gear 37 a is provided on the drum flange 37 and meshes with a transfer roller gear (not shown) provided on the transfer roller 4 to transmit a driving force to the transfer roller 4. Accordingly, the transfer roller 4 is driven to rotate in response to the rotation of the photosensitive drum 7.

The drum flange 37 has a fitting hole 3
7d is provided, and is supported by the shaft portion 100b of the drum shaft 100 provided on the drum frame 13. Drum shaft 1
Reference numeral 00 denotes an outer diameter portion 100a press-fitted into a press-fit inner diameter 13k provided in the drum frame 13 and fixed.

Further, a drum ground contact 700 is provided on the drum flange 37. Drum ground contact 7
Reference numeral 00 is made of a conductive material (eg, copper alloy, SUS, etc.), and is fixed to a drum ground contact mounting portion (not shown) provided on the drum flange 37 by heat welding or the like.

The drum ground contact 700 has first contact portions (not shown) at two locations on the outer periphery of a substantially disk-shaped base 700c, and a second contact portion is provided at a central portion between the first contact portions. It has a contact portion 700b.

Then, the first contact portion is pressed against the inner diameter portion 7d of the photosensitive drum 7, and the second contact portion 700b is
0 so as to elastically contact the front end surface 100c of the
The photosensitive drum 7 and the drum shaft 100 are electrically connected to each other at an outer diameter portion d.

The printer body 14 has a contact member 800
When the process cartridge B is mounted on the printer main body 14, the contact member 800 is electrically connected to the end face 100d of the drum shaft 100, and the photosensitive drum 7 can be grounded.

The drum flanges 36 and 37 may be made of a material such as polyacetal, polycarbonate, polyamide, or polybutylene terephthalate.
By using a resin material having good slidability such as hate), smooth drive transmission without noise, vibration, etc. can be achieved. However, another material having the same effect may be appropriately selected and used.

(2) Toner Remaining Detecting Means 20 In the above-described injection charging method, a long-term use may cause a reduction in charging performance, more specifically, a reduction in charging uniformity. This is mainly because the contact area between the charge-promoting particles and the photosensitive drum 7 is reduced by the toner, which is an insulator, accumulated little by little on the charging roller 8.

Here, in this embodiment, the charging performance is maintained by increasing the chances of contact between the charge promoting particles and the photosensitive drum 7. Specifically, the remaining amount of toner in the toner container 11A of the developing unit 9 is detected by the toner amount detecting unit 20 (FIG. 7), and the rotation speed of the charging roller 8 is changed according to the detected remaining amount of toner. Control is performed to vary the peripheral speed of the photosensitive drum 7 and the charging roller 8. Alternatively, the rotation speed of the charging roller 8 is changed in consideration of the remaining amount of toner and the life of the photosensitive drum 7, and the photosensitive drum 7 and the charging roller 8 are changed.
Control to vary the peripheral speed of the motor.

The arithmetic control means (CPU) calculates the toner consumption from the detected remaining toner amount, and changes the rotation speed of the charging roller 8 according to the calculated toner consumption.
Control for varying the peripheral speed of the photosensitive drum 7 and the charging roller 8 may be performed.

FIGS. 8, 9 and 10 show toner remaining amount detecting means for detecting the remaining amount of toner usable for development in the toner container 11A of the developing means 9. FIG.

FIG. 8 shows toner amount detecting means 2 according to the present invention.
FIG. 9 is a partially cutaway perspective view of the toner container for explaining the first embodiment, FIG. 9 is a front view showing one embodiment of the measurement electrode member and the reference electrode member, and FIG. FIG.

The detecting means 20 for detecting the amount of toner is for detecting the amount of toner in the toner container 11A of the developing means 9. In the present embodiment, the measuring electrode member 20A for detecting the amount of toner and the environment, that is, the environment, that is, , Detects the temperature and humidity of the atmosphere,
Reference electrode member 2 as a comparison member for outputting a reference signal
0B.

As shown in FIG. 8, for example, as shown in FIG. 8, the measuring electrode member 20A is located at a position in contact with the toner, such as the inner side surface or the bottom surface of the toner container 11A. They are arranged in such a direction that the contact area with the toner varies.

Further, the reference electrode member 20B is the measuring electrode member 2
It can be provided in the toner container 11A on the same side as where 0A is arranged, and at a location that does not come into contact with the toner.

The measuring electrode member 20A and the reference electrode member 20
B has a pair of electrodes formed in parallel on the substrate 22 at predetermined intervals, that is, an input-side electrode 23 and an output-side electrode 24.

In the present embodiment, as shown in FIG.
3 and 24 have at least a pair of electrode portions 23a to 23f and 24a to 24f arranged in parallel at a predetermined interval G, and each of the electrode portions 23a to 23f and 24a to 24f is connected to the connection electrode portions 23g and 24g. Are connected to each other,
The two electrodes 23 and 24 have a large number of uneven shapes combined with each other.

Of course, the electrode pattern of the measuring electrode member 20 is not limited to this, and as shown in FIG. 10, a pair of electrodes 23 and 24 are formed in a spiral shape arranged in parallel at a predetermined interval. It can also be formed.

According to the toner amount detecting means 20 as described above, the change in the contact area of the toner with the measuring electrode member 20A provided on the side surface or the bottom surface of the toner container 11A in the direction in which the toner decreases, that is, the measurement. Electrode member 20
The change in the capacitance of A is measured, and the toner amount of the entire toner container 11A is sequentially detected based on the measured value. The calculation of the toner amount is performed by the calculation control unit 651 based on the change information of the capacitance input from the toner amount detection unit 20 to the calculation control unit 651.

That is, since the dielectric constant of the toner is larger than that of air, the portion where the toner is in contact with the measuring electrode member 20A (the portion where the toner is present) is higher than the portion where the toner electrode is not in contact (the portion where the toner is not present). Is large.

Therefore, by measuring the change in the capacitance, the change in the amount of toner in the toner container 11A can be estimated.

The reference electrode member 20B is the same as the measurement electrode member 20A, and as shown in FIG. 9, a pair of input side electrodes 23 (23a to 23a) formed in parallel on the substrate 22 at a predetermined interval G. 23f) and the output side electrode 24 (24
a to 24f), the two electrodes 23 and 24 can be formed into a large number of uneven shapes combined with each other,
Further, as shown in FIG. 10, it may be formed in a spiral shape.

The reference electrode member 20B functions as a reference comparison member for the measurement electrode member 20A in order to cancel the fluctuation of the capacitance of the electrode member due to environmental conditions such as temperature and humidity.

That is, the output of the measurement electrode member 20A is compared with the output of the reference electrode member 20B which fluctuates due to a change in environment. For example, the predetermined capacitance of the reference electrode member 20B is set to the same value as the measurement electrode member 20A when there is no toner, and the difference between the output of the reference electrode member 20B and the output of the measurement electrode member 20A is calculated. Since it is possible to obtain an output of only the amount of change in the capacity, it is possible to enhance the accuracy of toner remaining amount detection.

Since the measuring electrode member 20A estimates the amount of toner in the toner container 11A by measuring the capacitance of the contact portion of the pattern surface, the value may vary depending on changes in the environment (humidity, temperature, etc.). fluctuate. For example, when the humidity increases, the amount of water vapor in the air increases, so that the dielectric constant of the atmosphere touching the detection member 20A also increases. Therefore, even when the toner amount is the same, if the environment changes, the output from the measurement electrode member 20A also changes. Further, if the material of the substrate 22 on which the pattern is formed also absorbs moisture, the dielectric constant changes due to the moisture absorption, so that the environment changes.

For this reason, the reference electrode member 20B as a comparison member which has the same environmental fluctuation as the measurement electrode member 20A, that is,
For example, a reference electrode member 20B having the same configuration as the measurement electrode member 20A and having a configuration not in contact with the toner is placed under the same environment as the measurement electrode member 20A, and both outputs are compared to obtain a difference and obtain a difference. , The remaining amount of toner can be measured without being affected by environmental fluctuations.

As described above, the toner container 11A is provided with the measurement electrode member 20A and the reference electrode member 20B for successively detecting the remaining amount of toner, but the detection means 20 for detecting the amount of toner further includes: Preferably, the developing means 9 is provided with an antenna rod, that is, an electrode rod 9h (FIG. 3) extending a predetermined length in the longitudinal direction of the developing roller 9c at a predetermined distance from the developing roller 9c.

With this configuration, toner end can be detected by detecting a change in capacitance between the developing roller 9c and the electrode rod 9h.

In the present invention, the toner amount detecting means 2
Although the configuration using the capacitance as 0 has been described, it is means for mechanically detecting the toner surface and sequentially detecting the remaining amount of toner as disclosed in JP-A-11-282239. No problem.

(3) Storage means 60 In FIGS. 3, 7, and 14, a storage means 60 is provided on the process cartridge B side. Information is exchanged between the storage means 60 and the arithmetic control means 651 of the printer body 14 via the read / write means 611.

The nonvolatile storage means 60 used in the present invention
There is no particular limitation as long as the signal information can be stored and held in a rewritable manner. For example, electrical storage means such as a RAM and a rewritable ROM, a magnetic recording medium, a magnetic bubble memory, and a magneto-optical memory Magnetic storage means such as the above are used.

In the present embodiment, an NV (Non Volatile) RAM is used in terms of ease of handling and cost.

The storage means 60 stores a data map of an appropriate rotation speed of the charging roller 8 according to the amount of toner remaining in the process cartridge B, or the toner amount detecting means 2.
0 (information on toner consumption / toner consumption)
Information on the remaining amount of toner) and the sliding distance L between the photosensitive drum 7 and the charging roller 8 are written.

Writing is performed at the timing when a certain amount of toner is consumed, when the recording medium 2 is printed by a certain amount, or when the sliding distance L is consumed by a certain amount.

(4) Controlling the Number of Revolutions of the Charging Roller 8 In this embodiment, the optimal number of revolutions of the charging roller stored in the storage means 60 is determined by the toner container 11A
When the amount of toner in the box reaches a certain amount of toner, it is called, and the number of rotations of the charging roller is changed accordingly.

FIG. 11 shows the relationship between the amount of toner and the number of rotations of the charging roller in this embodiment.

From the unused state of the process cartridge B to the consumption of a certain amount of toner, the initial rotation speed n1
To rotate the charging roller 8. The initial rotation speed is also recorded in the storage means 60.

The arithmetic control means 651 detects the toner consumption by the toner amount detection means 20 successively or periodically, and the second drive control means 5 until the specified amount XT1 is consumed.
In step 02, the driving of the second drive motor 501 is controlled such that the rotation speed of the charging roller 8 continues at the initial rotation speed n1.

At the time of XT1, XT1
Thereafter, the optimum rotation speed n2 is called, and the charging roller 8 is driven at the rotation speed n2.

Similarly, from XT1 to XT2,
It is driven at the rotation speed n2, and after the time of XT2, the storage means 60
Then, the next optimal rotational speed n3 is called to change the rotational speed.

By repeating this procedure, the number of rotations of the charging roller can be set to an optimum value up to the toner consumption limit. That is, the charging performance is maintained by increasing the chances of contact between the charge promoting particles and the photosensitive drum 7.

The mounting portion of the storage means 60 can be mounted on the image forming apparatus main body, or can be mounted on each process cartridge.

When the storage means 60 is provided in the process cartridge B, the image forming apparatus can be used when it is desired to change the conditions after the start of production, for example, when it is desired to discover a new high-performance material and change the parts. There is a possibility that it can be handled only by changing the data map without changing the main unit.

(Second Embodiment) In this embodiment, the first
In addition to the toner consumption of the embodiment, the rubbing distance between the photosensitive drum 7 and the charging roller 8 is used as a parameter for controlling the rotation speed of the charging roller 8. That is, the accumulated distance of rubbing of the photosensitive drum 1 and the charging roller 8 is stored in the storage unit 60.
When the amount of toner in the toner container 11A of the developing means 9 reaches a certain remaining amount of toner, the optimum number of charging rollers according to the rubbing distance is called, and the rotation number of the charging roller is changed accordingly.

By considering the rubbing distance, the life margin of the photosensitive drum 7 can be effectively used as a margin for uniform charging.

A method of changing the rotation speed of the charging roller 8 in this embodiment will be described with reference to FIG. FIG. 12 is a graph showing the relationship between the toner amount, the rubbing distance, and the peripheral speed difference in the control according to the present embodiment.

First, the graph of FIG. 12 showing the relationship between the toner consumption, the rubbing distance and the peripheral speed difference will be described. This shows the relationship between the toner consumption during use of the process cartridge and the rubbing distance between the photosensitive drum 7 and the charging roller 8. The horizontal axis indicates the toner consumption, and the vertical axis indicates the rubbing distance.

A) Sliding Distance and Drum Life In the charge injection charging system of the present invention, it is important to increase the chances of contact between the charge promoting particles and the photosensitive drum 7.
For this purpose, the charging roller 8 and the photosensitive drum 7 are driven to rotate in the same direction.

Assuming that the peripheral speed of the surface of the photosensitive drum 7 on the contact surface between the photosensitive drum 7 and the charging roller 8 is Va and the peripheral speed of the surface of the charging roller 8 is Vb, the peripheral speed difference between the photosensitive drum 7 and the charging roller 8 V is given by V = Va + Vb.

Although the peripheral speed Va of the surface of the photosensitive drum 7 is often constant, there is a mode in which the peripheral speed Va of the photosensitive drum 7 is slowed down in order to record at a high resolution. Some of them perform multi-speed control of the peripheral speed Va) of the photosensitive drum 7. Specifically, in FIG. 7, the rotation of the photosensitive drum 7 as an image carrier is performed by a first drive motor 600 as a first drive unit, and the rotation speed (peripheral speed) of the photosensitive drum 7 is controlled by arithmetic control. The means 651 controls the first drive motor 600 by the first drive control means 601.

The rubbing distance L at the contact portion between the photosensitive drum 7 and the charging roller 8 is represented by the product L = V × T of the peripheral speed difference V and the rotation driving time T of the photosensitive drum 7 and the charging roller 8. It is obtained by calculation by the arithmetic control means.

The life of the photosensitive drum 7 is determined by the shaving amount on the surface of the photosensitive drum 7, and the shaving amount has a linear relationship with the rubbing distance L, that is, the rubbing distance L is a certain value LL ( When the friction limit is reached, the photosensitive drum 7
Will end its life. The sliding limit LL is stored in advance in the storage means 60 of the process cartridge B.

B) Reading / writing of the toner consumption X and the rubbing distance L The toner consumption X and the rubbing distance L are stored at a certain timing by the arithmetic control unit 651 through the read / write unit 611 and the storage unit 60 of the process cartridge B. Is written / read.

In the present embodiment, the writing timings (X1, X2,
…). At this timing, the toner consumption X
And the data of the sliding distance L are stored in the storage means 60 as a set.

As another example, the writing may be performed at a timing when the recording medium 2 is printed by a predetermined amount or when the sliding distance L is consumed by a predetermined amount.

C) Target rubbing distance FIG. 12 shows the relationship between the toner consumption and the rubbing distance.

A straight line 1 is a straight line when the toner is consumed at a standard printing rate and the rotation speed of the charging roller in the initial stage of the process cartridge is continued. The vertical axis in FIG. 12 shows the rubbing limit distance. The difference between the rubbing distance Ln of the straight line 1 at the toner consumption limit and the rubbing limit is a margin relating to the life of the photosensitive drum.

The target rubbing distance is set to a value closer to the rubbing limit distance than Ln. By increasing the number of rotations of the charging roller until the toner consumption limit is reached, the target rubbing distance is approached.

D) Timing of Changing the Number of Revolutions of Charging Roller When the process cartridge is started, the charging roller is driven at a predetermined number of revolutions.

The possibility that the developer accumulates on the charging roller is as follows.
This is the latter half of the life of the process cartridge B. In the method described here, the point at which 3/4 of the toner capacity has been consumed is set as the change timing. The timing is not limited to this.

E) Number of rotations of charging roller FIG. 12 shows the relationship between the toner consumption and the rubbing distance when the number of rotations of the charging roller is changed.

The broken lines 1 and 2 are examples of histories that have formed different images.

Until the rotation speed change point XT, the rotation speed of the charging roller remains in the initial state. However, the rubbing distance at the rotation speed change point XT differs depending on the magnitude of the image printing rate.

The rubbing distance at the rotational speed change point XT is read from the storage means 60, and the number of rotations corresponding to the rubbing distance is called. As the number of revolutions, the number of revolutions approaching the target rubbing distance is recorded in the storage means 60.

The example of the broken line 1 in FIG.
At this point, the sliding distance L1 is small. According to this L1,
The rotation speed n2 is selected from the storage means 60. n2 is larger than the rotation speed at the start of use so as to reach the target rubbing distance. The dashed line 1 changes in the direction of arrow 1 by increasing the rotation speed.

The broken line 2 has a longer sliding distance than the broken line 1. The change rotation speed given at the rotation speed change point is n5 <n2, but the rotation speed is also increased to move to the target sliding distance.

As described above, when a certain amount of toner has been consumed, the peripheral speed between the photosensitive drum 7 and the charging roller 8 is variably controlled by increasing the rotation speed of the charging roller 8 according to the rubbing distance. Thus, the chargeability can be maintained over a long period of use.

(Third Embodiment) FIG. 13 is a graph illustrating the relationship between the toner consumption and the rubbing distance for explaining the present embodiment. In this embodiment, a more detailed control method is adopted.

In this embodiment, the number of rotations of the charging roller is aimed at charging uniformity near the life of the process cartridge B.

In the present embodiment, an example will be described in which the change in the number of rotations of the charging roller is performed a plurality of times so that high charging properties can be exhibited for a longer period of time.

Here, an example will be used in which two changes are made, namely, timing XT1 at which the toner consumption is １ ／ and timing XT2 at 、 ３. The number of changes is not limited to two.

Dashed lines 1 and 2 show examples of histories of printing different images.

The dashed line 1 indicates the charging roller rotation speed change point XT1
, The number of revolutions is changed to n11 as in the first embodiment. When the amount of toner remaining after the rotation speed is changed is large, and thereafter the image formation whose printing rate is greatly different from that before the rotation speed change is repeated, the deviation from the target rubbing distance may be large.

However, when a certain amount of toner is consumed (XT2), the rotation speed of the charging roller is changed again, and
It is possible to return to the target rubbing distance again.

As described above, by changing the number of revolutions of the charging roller 8 in multiple stages, the margin of the photosensitive drum 7 can be effectively used regardless of the variation of the printing rate or the number of sheets continuously printed. As a result, the chargeability of the process cartridge can be maintained for a long time.

The timing for storing the history data is set every time the parameter is consumed by a certain amount, but it is not necessary to limit the parameter to a certain amount.

(Fourth Embodiment) In the first to third embodiments, the storage means 60 only stores data on the number of rotations of the charging roller.

In this embodiment, how the user used the process cartridge B before the life of the process cartridge B is recorded. The recorded contents are the history of the rubbing distance and the remaining amount of toner.

A method for controlling the number of rotations of the charging roller 8 according to the present embodiment will be described with reference to FIGS. 14, 15 and FIGS.

FIG. 15 is a graph showing the relationship between the toner amount, the rubbing distance, and the peripheral speed difference in the control according to the present embodiment. FIGS. 16 to 18 are flowcharts illustrating the control method according to the present embodiment.

First, the graph of FIG. 15 showing the relationship between the toner consumption, the rubbing distance and the peripheral speed difference will be described. This shows the relationship between the toner consumption during use of the process cartridge and the rubbing distance between the photosensitive drum 7 and the charging roller 8. The horizontal axis indicates the toner consumption, and the vertical axis indicates the rubbing distance.

A) Toner Consumption X The toner consumption X is calculated by calculating the difference between the initial toner amount and the current toner amount by the arithmetic and control unit 651 based on the information obtained by the toner amount detection unit 20. Desired. The toner consumption X is stored in the storage unit 60 of the process cartridge B. The toner consumption limit XX is a limit amount at which toner can be consumed. The value of the toner consumption limit XX is
It is stored in the storage means 60 of the process cartridge B in advance.

B) Sliding distance L The sliding distance L at the contact portion between the photosensitive drum 7 and the charging roller 8 is determined by the difference between the peripheral speed difference V and the rotational driving time T between the photosensitive drum 7 and the charging roller 8 as described above. The product L = V × T is obtained by calculation by the arithmetic control means.

The rubbing limit LL is a limit value at which rubbing is possible. The sliding limit LL is stored in advance in the storage means 60 of the process cartridge B.

C) Reading / writing of toner consumption X and rubbing distance L The toner consumption X and rubbing distance L are written / read to / from the storage means 60 of the process cartridge B through the read / write means 611 at a certain timing. You.

In the present embodiment, the timing (X1, X2,
…). At this timing, the toner consumption X
And the data of the sliding distance L are stored in the storage means 60 as a set.

As another example, the writing may be performed at the timing when the recording medium 2 is printed by a predetermined amount or when the sliding distance L is consumed by a predetermined amount.

D) Sliding predicted value LA The points (P0, P1, P2,
.. Pj-2, Pj-1, Pj) are data sets of the toner consumption X and the sliding distance L stored in the process cartridge B.

When the process cartridge B is started to be used (P
0) to the present (Pj).

Using this data, the toner consumption limit X
The rubbing distance in X is predicted.

A predicted straight line 1 representing the relationship between the toner consumption X and the rubbing distance L is obtained by using two points P0 and Pj, and further, a predicted rubbing value LA at the toner consumption limit XX is obtained.
In this embodiment, two points P0 and Pj are used to obtain the prediction line, but a method of performing a first-order approximation using P0, P1,..., Pj-1, Pj may be used.

E) Controlling the number of rotations of the charging roller The predicted sliding value LA is compared with the sliding limit LL. If the predicted sliding value LA is smaller than the sliding limit LL, the life margin of the photosensitive drum 7 alone is reduced This means that the rotation speed of the charging roller 8 is increased (the peripheral speed difference is increased) and the margin of the photosensitive drum 7 is effectively used for maintaining the charging performance.

Specifically, the peripheral speed difference V from P0 to Pj
Is set to V1 and the peripheral speed difference after Pj is set to V2, and V2 is controlled so that the portion after Pj is on the control line 1 (V1 <V
2).

The control line is a line connecting two points of Pj (Xj, Lj) and the rubbing limit PP (XX, LL), and the toner consumption X and the rubbing distance L change in a relationship satisfying this line. In this case, the life of the toner and the photosensitive drum 7 can be consumed at the same time.

Since a proportional relationship is established between the inclination of the prediction line 1 and the control line 1 and the peripheral speed difference V, V1: V2 = Lj / Xj: (LL-Lj) / (XX-X
j) From the above equation, the peripheral speed difference V2 = ((LL−Lj) / (XX−Xj)) /
(Lj / Xj) × V1 is obtained.

Further, since the peripheral speed difference V2 is the sum of the peripheral speed Va on the surface of the photosensitive drum 7 and the peripheral speed Vb on the surface of the charging roller 8, V2 = Va + V2b (where V2b is the peripheral speed of the charging roller 8 after control, Va V2b is calculated from V2b = V2-Va.

The rotational speed n2 of the charging roller 8 can be obtained by dividing the peripheral speed V2b by the radius of the charging roller.

Thereafter, the charging roller 8 is driven to rotate at the rotation speed n2 just obtained.

The control method described above will be described with reference to the flowcharts of FIGS.

Step 1: When the power is turned on to the printer main body 14, or when the insertion of the CRG is detected, the process proceeds to step 2.

Step 2: In step 2, it is determined whether the inserted process cartridge B is new. The information as to whether or not the cartridge is new is determined based on whether or not the toner consumption history and the rubbing history are written in the storage means 60 provided in the process cartridge. If this history has not been written, it is determined that it is new, and the process proceeds to step 3. If it has been written, the process proceeds to step 4 because it is not new.

Step 3: If new, initial values of toner consumption history and rubbing history P0 (X0, L0) = (0,
0) and the final information P (X, L) = (0,0)
Write to 0. After writing, go to step 4.

Step 4: Latest toner consumption history information X
k is read from the storage means 60.

Step 5: The final toner consumption information X and the rubbing information L are read from the storage means 60.

Step 6: The optimal rotation speed n2 is read in order to determine whether the optimal control of the charging roller 8 has already been performed. If the data can be read normally, the process proceeds to step 22 because the optimal control is performed. If the data cannot be read, the process proceeds to step 7 because the data is not controlled.

Steps 7, 8, and 9: While the photosensitive drum 7 and the charging roller 8 are rotating, the photosensitive drum 7 and the charging roller 8 are rotated.
The sliding distance L is integrated from the peripheral speed difference and the rotation time. The rubbing distance L is the total rubbing distance from the start of use. When the rotation has stopped, the process proceeds to step 10. Step 10: The remaining toner amount is measured using the toner amount detecting means 20, and the current toner consumption amount is calculated.

Step 11: After stopping rotation, storage means 20
Is updated by overwriting the final information of the toner consumption X and the rubbing distance L recorded in.

Step 12: Each time a certain amount of toner XC is consumed, the information of the toner consumption and the rubbing distance is added to the storage means 20 as a history and written. Latest history toner consumption X
Calculate the increase in toner consumption from k (X-Xk).

If a certain amount of XC has been consumed, the history is added, so the flow proceeds to step 13, and if not, the flow proceeds to step 7.

Step 13: Since the history is increased, the subscript k is incremented.

Step 14: The final information P (X, L) is additionally written as the latest history Pk (Xk, Lk) in the storage means 20.

Step 15: Since the deterioration of the charging performance occurs in the latter half of the life of the CRG, it is desirable to control the rotation of the charging roller 8 at a relatively late stage. The result is shrinking unnecessarily.

Therefore, in the present invention, the late CRG life (CRG
The toner consumption amount XT (about 60 to 80% of the G life) is set as a trigger for starting the rotation speed control of the charging roller 8. When the toner consumption amount X exceeds the toner consumption amount XT serving as the trigger, the process proceeds to step 17 and thereafter to perform the rotation speed control.
On the other hand, if it is lower, it is determined that there is no need to control the rotational speed, and the process returns to step 7.

The toner consumption XT as a trigger is shown in FIG.
Corresponds to Xj.

Step 16: The optimum rotation speed n2 is determined in order to determine whether the optimal control of the charging roller 8 has already been performed.
Read.

If the data can be read normally, the flow proceeds to step 7 because the optimal control is being performed. Until the toner is completely used, the rubbing distance L and the toner consumption X are integrated, and stored in the storage unit 6.
Proceed to step 7 to record 0.

When data cannot be read, the optimum rotational speed n
The process proceeds to step 17 to perform the rotation drive control in step 2.

Step 17: The initial value P0 (X0, L0) and the latest history Pk (Xk, L
Call k). In FIG. 15, it corresponds to Pj (Xj, Lj).

Step 18: The calculation control means 651 calculates the predicted rubbing value LA.

Step 19: The rub limit LL is compared with the predicted rub value LA. If the predicted rubbing value LA is smaller than the rubbing limit LL, it can be estimated that there is a margin in the drum life, and the process proceeds to step 20 for controlling the rotation speed of the charging roller 8. If the predicted rubbing value LA is not smaller than the rubbing limit LL, proceed to Step 7 Step 20: Calculate the optimum rotation speed of the charging roller 8. For that purpose, first, the optimum peripheral speed difference V2 is calculated. From this, the optimum rotation speed n2 of the charging roller 8 is determined.

Step 21: The optimum rotational speed n2 is written in the storage means 60.

Step 22: The second drive control means switches to a mode in which the charging roller 8 is driven at the optimum rotation speed n2.

Until the entire amount of toner is used, the rubbing distance L and the toner consumption amount X are continuously integrated, and the process proceeds to step 7 to record the result in the storage means 60.

As described above, using the history of the toner consumption amount L and the sliding distance L between the photosensitive drum 7 and the charging roller 8,
By calculating the margin of the photosensitive drum 7 and performing optimal control of the charging roller 8 in accordance with the margin to increase the number of rotations, the charging property can be maintained over a long period of use.

(Fifth Embodiment) FIG. 19 is a graph illustrating the relationship between the toner consumption and the rubbing distance according to a fifth embodiment. In this embodiment, a more detailed control method is adopted.

Since the control line of the fourth embodiment is based on the assumption that the past state will continue in the future, a deviation from the actual state may occur. This is because the relationship between the toner consumption and the rubbing distance changes depending on variations in the printing ratio, the number of sheets continuously printed, and the like.

In the fourth embodiment, the trigger for optimally controlling the drive of the charging roller 8 is only one. However, in the present embodiment, a plurality of triggers are provided to perform finer control.

In this embodiment, the difference from the fourth embodiment is the portion after the control trigger XT1 of the charging roller 8, and this portion will be described.

1) Control of Number of Revolutions of Charging Roller 8: First Section When the toner consumption reaches XT1, the predicted straight line 1 and the sliding line L are obtained from the history of the toner consumption X and the rubbing distance L from the initial toner consumption to the trigger XT1. A control straight line 1 is calculated from the history and the rub limit PP (XX, LL) as the rub predicted value LA1.

An optimum rotation speed n2 of the charging roller 8 is obtained from the predicted straight line 1 and the control straight line 1.

Thereafter, the charging roller 8 is driven to rotate at the optimum rotation speed n2.

Since the predicted rubbing value LA1 is smaller than the rubbing limit LL, the rotation speed of the charging roller 8 is increased (n
2> n1).

In FIG. 19, only a part of the control line 1 is drawn in consideration of the legibility of the figure, but the tip of the control line 1 points to the sliding limit point PP.

2) Charging Roller 8 Revolution Control: Second Section When the toner consumption reaches XT2, the prediction straight line 2 and the rubbing prediction are made from the history of the toner consumption X from the trigger XT1 to the trigger XT2 and the rubbing distance L. A control line 2 is obtained from the value LA2 based on the history and the sliding limit PP (XX, LL).

The optimum rotation speed n3 of the charging roller 8 is obtained from the predicted straight line 2 and the control straight line 2.

After that, the charging roller 8 is driven to rotate at the optimum rotation speed n3.

Since the predicted rubbing value LA2 is larger than the rubbing limit LL, the rotation speed of the charging roller 8 is reduced (n
3 <n2).

In FIG. 19, only a part of the control line 2 is drawn in consideration of the legibility of the figure, but the tip of the control line 2 points to the sliding limit point PP.

3) Controlling the Number of Revolutions of the Charging Roller 8: Third Section When the toner consumption reaches XT3, the history of the toner consumption X from the trigger XT2 to the trigger XT3 and the sliding distance L rub against the predicted straight line 3. For the predicted value LA3, a control straight line 3 is obtained from the history and the rubbing limit PP (XX, LL).

An optimum rotation speed n4 of the charging roller 8 is obtained from the predicted straight line and the control straight line 3.

Thereafter, the charging roller 8 is driven to rotate at the optimum rotation speed n4.

Since the predicted rubbing value LA3 is smaller than the rubbing limit LL, the rotation speed of the charging roller 8 is increased (n
4> n3).

In FIG. 19 , only a part of the control line 3 is drawn in consideration of the legibility of the figure, but the tip of the control line 3 points to the sliding limit point PP.

In the first to third sections, the history data of the toner consumption X and the rubbing distance L are recorded in the storage means in the same manner as in the preceding sections.

As described above, by controlling the number of rotations of the charging roller 8 in multiple stages, accurate control is possible regardless of variations in the printing rate and the number of sheets to be continuously printed. By effectively utilizing the margin, it is possible to maintain the chargeability of the process cartridge for a long time.

Although the control section is divided into three sections in the present embodiment, it is not necessary to limit the control section to three sections.

Although three data histories are defined as one section, it is not necessary to limit the data history to three data histories.

Furthermore, although the history data is stored every time a certain amount of toner is consumed, the storage timing may use parameters such as the sliding distance and time.

The timing for storing the history data is set each time the parameter is consumed by a certain amount, but it is not necessary to limit the parameter to a certain amount.

(Sixth Embodiment) A sixth embodiment will be described with reference to FIG. FIG. 20 is a graph illustrating the control method according to the present embodiment. In this embodiment, a more detailed control method is adopted.

The error LE of the rubbing distance L at the toner consumption limit XX between the control line (i) derived from the prediction and the actual line (i + 1) approximating the actual history is the ratio of the deviation between the predicted and actual deviations. If they are the same, the earlier the control is performed, the larger the control becomes.

As in the second embodiment, when shifting from the optimum rotation speed n2 to the optimum rotation speed n3, it is not desirable to decrease the rotation speed, and the rotation speed of the charging roller 8 is gradually increased. Is desirable.

Therefore, in this embodiment, the number of revolutions of the charging roller is gradually increased by gradually changing the rubbing limit LL (the rubbing target value) used as the target of the control straight line step by step with use. Adopt a method of

A specific description will be given with reference to FIG. FIG. 21 is a graph illustrating the relationship between the toner amount, the rubbing distance, and the peripheral speed difference in the control according to the present embodiment. In the present embodiment, the difference from the above-described second embodiment is that the charging roller 8 is different. Since this is the part after the control trigger XT1, this part will be described.

1) Control of Number of Revolutions of Charging Roller 8: First Section When the toner consumption reaches XT1, the predicted straight line 1 and the sliding line L are obtained from the history of the toner consumption X from the initial toner consumption to the trigger XT1 and the sliding distance L A control straight line 1 is obtained from the predicted friction value LA1 from the history and the target friction value LL1.

The rubbing target value LL1 is a value that internally divides the rubbing limit LL and the predicted rubbing value LA1 into s: t, and is represented by LL1 = (t × LL + s × LA1) / (s + t). In this embodiment, s: t = 1: 1.

An optimum rotation speed n2 of the charging roller 8 is obtained from the predicted straight line 1 and the control straight line 1.

Thereafter, the charging roller 8 is driven to rotate at the optimum rotation speed n2.

Since the predicted rubbing value LA1 is smaller than the target rubbing value LL1, the rotation speed of the charging roller 8 is increased (n2> n1).

2) Charging Roller 8 Revolution Control: Second Section When the toner consumption reaches XT2, a predicted sliding value LA2 is predicted from the history of the toner consumption X from the trigger XT1 to the trigger XT2 and the sliding distance L. A straight line 2 is obtained from the history and the rubbing target value LL2.

The rubbing target value LL2 is a value that internally divides the rubbing limit LL and the predicted rubbing value LA2 into s: t, and is expressed by LL2 = (t × LL + s × LA2) / (s + t). In this embodiment, s: t = 1: 1.

An optimum rotation speed n3 of the charging roller 8 is obtained from the predicted straight line 2 and the control straight line 2.

After that, the charging roller 8 is driven to rotate at the optimum rotation speed n3.

Since the predicted rubbing value LA2 is smaller than the target rubbing value LL2, the rotation speed of the charging roller 8 is increased (n3> n2).

3) Charging Roller 8 Rotational Speed Control: Third Section When the toner consumption reaches XT3, the predicted sliding value LA3 is predicted from the history of the toner consumption X from the trigger XT2 to the trigger XT3 and the sliding distance L. A straight line 3 is obtained from the history and the rubbing target value LL3.

The rubbing target value LL3 is a value that internally divides the rubbing limit LL and the predicted rubbing value LA3 into s: t, and is represented by LL3 = (t × LL + s × LA3) / (s + t). In this embodiment, s: t = 1: 1. However, since the third section is the last section, s: t = 0: 1 may be set.

The optimum rotation speed n4 of the charging roller 8 is obtained from the predicted straight line 3 and the control straight line 3.

Thereafter, the charging roller 8 is driven to rotate at the optimum rotation speed n4.

Since the predicted rubbing value LA3 is smaller than the target rubbing value LL3, the rotation speed of the charging roller 8 is increased (n4> n3).

In the first to third sections, the history data of the toner consumption X and the rubbing distance L are recorded in the storage means in the same manner as in the preceding sections.

As described above, by gradually approaching the rubbing target value LAi to the rubbing limit value LL, the number of revolutions of the charging roller 8 can be increased in a stepwise manner.
By effectively utilizing the margin, the chargeability of the process cartridge can be maintained for a long time. In the present embodiment, the control section is divided into three blocks, but it is not necessary to limit the control section to three blocks.

Although three data history sentences are one block, this need not be limited to three data.

Further, although the history data is stored every time a certain amount of toner is consumed, the storage timing may use parameters such as the rubbing distance and time.

The timing for storing the history data is set each time the parameter is consumed by a certain amount, but it is not necessary to limit the parameter to a certain amount.

The rubbing distance in the first to sixth embodiments may be replaced with the rubbing time, that is, the rotation time of the charging roller 8.

(Seventh Embodiment) In the sixth embodiment,
The description will be made on the assumption that the printer main body 14 has a plurality of image forming process speeds.

A) Correlation between process speed and chargeability For example, a printer main body having a mode at a speed p times the basic speed and capable of printing in a plurality of modes.

The peripheral speed of the photosensitive drum 7 in the uncontrolled state at the basic speed is Va, and the peripheral speed of the charging roller 8 is Vb.
In order to maintain the same chargeability as the basic speed at a p-fold process speed, it is necessary to make the peripheral speed ratio between the photosensitive drum 7 and the charging roller 8 the same.

Va / Vb = const. b) Relationship between the peripheral speed of the photosensitive drum 7 and the peripheral speed of the charging roller 8 during multi-mode printing The relationship between the peripheral speed of the photosensitive drum 7 and the peripheral speed of the charging roller 8 during multi-mode printing will be described using Table 1. .

[0295]

[Table 1]

[0296] In the basic mode, the drum peripheral speed when the basic mode is not controlled is Va, and the charging roller peripheral speed is Vb. The charging roller peripheral speed V2b during control is
As described in the above embodiment, the value is obtained from the relationship between the sliding limit LL (sliding target value) and the predicted sliding value LA. The peripheral speed of the photosensitive drum at the time of control is the same speed (Va) as at the time of non-control.

[0297] Next, the peripheral speeds of the photosensitive drum 7 and the charging roller 8 in other modes will be described.

It is assumed that the process speed at this time is p times that of the basic mode. Therefore, the drum peripheral speed Va_p = Va × p
It is. Further, even when the charging roller is controlled, the peripheral speed of the photosensitive drum is unchanged and Va_p.

In addition, the peripheral speed of the charging roller in the uncontrolled state is Vb_p = Vb × p, where the peripheral speed of the charging roller is Vb_p in order to maintain the same charging performance as in the basic mode.

The peripheral speed ratio Va_p / Vb_p at the p-times process speed (when not controlled) becomes the same as the basic speed Va / Vb.

In the control mode, the same charging performance as in the basic mode is maintained as in the non-control mode, so that the ratio between the peripheral speed in the basic mode and the peripheral speed in the other modes is the same.

Assuming that the peripheral speed of the charging roller at the time of control is V2b_p, Va / V2b = Va_p / V2b_p may be satisfied.

Since Va_p = Va × p, V2b
_P = V2b × p.

Therefore, the drive control of the charging roller 8 other than in the basic mode is performed by first setting the charging roller peripheral speed V2b in the basic mode.
Then, p is obtained from the process speeds of both modes, and the driving of the charging roller 8 may be controlled at a peripheral speed (V2b × p) obtained by multiplying V2b by p.

When the printer has a plurality of process speeds, it is necessary to control the contact charging member using the rubbing distance instead of the rubbing time.

(Eighth Embodiment) In the first to seventh embodiments, it is assumed that the algorithm for controlling the charging roller 8 is stored in a ROM (not shown) stored in the printer body 14. Alternatively, the algorithm may be recorded in the storage means 60 of the process cartridge B, which is a consumable part, and read out from the storage means 60 as needed by the printer main body 14, and the rotation speed of the charging roller 8 may be controlled in accordance with the algorithm. Conceivable.

This is because, after the use of the process cartridge B, the process cartridge B is collected, the history of the toner consumption X and the rubbing distance L recorded in the storage means 60 are read, and this data is analyzed. The user's usage status can be grasped in more detail.

By storing the rotation control algorithm of the charging roller 8 in the process cartridge B, improved versions of the algorithm can be easily provided to the user one after another, and customization for a specific user is also possible.

(Ninth Embodiment) In the first to sixth embodiments, the rotation speed n of the charging roller 8 is derived from the control line and the prediction line.

However, it is desirable to set the lower limit of the number of revolutions from the viewpoint of the charging performance and the upper limit of the number of revolutions from the influence on the image.

Therefore, after calculating the optimum rotation speed n of the charging roller 8, a step is provided for checking that the rotation speed is within the upper and lower limits. If the calculation result is lower than the lower limit, the rotation speed of the charging roller 8 is corrected to the lower limit value, and if the calculation result is higher than the upper limit, the rotation speed of the charging roller 8 is corrected to the upper limit value.

Although the process cartridge B described above is for forming a single color image, the process cartridge is not limited to forming a single color image, but a plurality of process cartridges may be provided and a plurality of color images (for example, The present invention can be suitably applied to an image forming apparatus for forming a two-color image, a three-color image, or a full-color image.

The electrophotographic photosensitive member as the image bearing member is not limited to the photosensitive drum, and includes, for example, the following. First, a photoconductor is used as the photosensitive member. Examples thereof include amorphous silicon, amorphous selenium, zinc oxide, titanium oxide, and organic photoconductor (OPC).

Incidentally, a drum-shaped one is generally used, in which a photoconductor is deposited or coated on a cylinder of aluminum alloy or the like.

The image carrier may be an electrostatic recording dielectric for an electrostatic recording process.

The contact charging means is not limited to the injection charging method using the charge accelerating particles as in the embodiment.

The material for forming the toner frame 11 and the developing frame 12 is a plastic such as polystyrene or AB.
S resin (acrylonitrile / butadiene / styrene copolymer), modified PPE resin (polyphenylene ether),
Modified PPO resin (polyphenylene oxide), polycarbonate, polyethylene, polypropylene and the like.

The process cartridge described above is
For example, an electrophotographic photosensitive member and at least a charging unit are provided. Accordingly, as a mode of the process cartridge, in addition to the embodiment described above, for example, an electrophotographic photosensitive member, a developing unit, and a charging unit may be integrally formed as a cartridge so as to be detachable from the apparatus main body. In some cases, the electrophotographic photosensitive member and the charging unit are integrally formed into a cartridge and made detachable from the apparatus main body.

That is, the above-mentioned process cartridge is a cartridge in which the developing means, the charging means and the electrophotographic photosensitive member are integrally formed into a cartridge, and this cartridge is detachably mountable to the main body of the image forming apparatus. . In addition, the charging means and the electrophotographic photosensitive member are integrally formed into a cartridge so that the cartridge can be attached to and detached from the image forming apparatus main body.

Further, in the above-described embodiment, a laser beam printer is exemplified as the image forming apparatus. However, the present invention is not limited to this. For example, an electrophotographic copying machine, a facsimile machine, or another image forming apparatus such as a word processor may be used. Naturally, it can also be used for forming equipment.

The effects of the image forming apparatuses according to the first to ninth embodiments described above are summarized in that the charging performance is appropriately maintained over a long period of use.

By increasing the number of revolutions of the charging roller 8 to the speed written in the storage means 60 in accordance with the consumption of the toner, the charging property can be maintained for a long time.

Using the toner consumption amount L and the rubbing distance L between the photosensitive drum 7 and the charging roller 8, optimal control of the charging roller 8 is performed to increase the number of rotations, thereby effectively utilizing the drum life margin. Thus, the chargeability can be maintained over a long period of use.

By controlling the number of rotations of the charging roller 8 in multiple stages, accurate control can be performed regardless of variations in the printing rate and the number of sheets continuously printed, and the chargeability of the process cartridge can be maintained for a long time. Become.

The rubbing target value LAi is gradually increased to the rubbing limit value LL.
, The number of revolutions of the charging roller 8 can be increased stepwise, and the chargeability of the process cartridge can be maintained for a long time.

The life of the photosensitive drum is not the rubbing time,
Since the rubbing distance is controlled, even when a plurality of image forming process speeds are provided, the life can be accurately controlled. That is, when managing by time, accurate lifetime management cannot be performed under a plurality of image forming process speed conditions.

By recording the history of the toner consumption X and the rubbing distance L in the storage means 60 of the process cartridge B,
Even if the process cartridge is used in another printer main body, it is possible to maintain the charging property for a long time by optimal charging roller control.

By recording the history of the toner consumption X and the rubbing distance L in the storage means 60 of the process cartridge B,
After the use of the process cartridge B, the process cartridge B is collected, the history of the toner consumption X and the rubbing distance L recorded in the storage unit 60 are read, and the data is analyzed so that the user's use situation can be improved. Can understand in detail.

Even when the specification of the process cartridge B is changed, if the data stored in the storage means is changed, the optimum rotation speed of the charging roller 8 can be maintained without changing the image forming apparatus main body. it can.

Even when the rotational speed of the contact charging member is not within the predetermined range, the rotational speed can be controlled within the predetermined range, so that the charging performance can be maintained.

[0331]

According to the present invention, the rotational speed of the contact charging member is increased to the speed written in the storage means in accordance with the consumption of the developer detected by the detection means for detecting the amount of the developer. As the durability increases, the chance of contact of the contact charging member with the image carrier increases, so that the chargeability can be maintained for a long time.

Also, by utilizing the consumption of the developer and the rubbing distance between the image bearing member and the contact charging member, optimal control of the contact charging member is performed to increase the number of revolutions, thereby making the life margin of the image bearing member effective. The chargeability can be maintained over a long period of use.

Further, by controlling the number of rotations of the contact charging member in multiple stages, accurate control can be performed regardless of variations in the printing rate, the number of sheets continuously printed, and the like, and the chargeability of the process cartridge can be maintained for a long period of time. It becomes possible.

By gradually approaching the rubbing target value to the rubbing limit value, the number of revolutions of the contact charging member can be increased stepwise, and the chargeability of the process cartridge can be maintained for a long time.

Since the life of the image carrier is controlled not by the rubbing time but by the rubbing distance, the life can be accurately controlled even when a plurality of image forming process speeds are provided.

Further, by recording the history of the consumption amount of the developer and the rubbing distance in the storage means of the process cartridge, even if the process cartridge is used in another image forming apparatus main body, the chargeability by the optimal control of the contact charging member is controlled. Can be maintained for a long time.

Further, by recording the history of the consumption amount of the developer and the rubbing distance in the storage means of the process cartridge, after the use of the process cartridge is completed, it is collected and stored in the storage means. By reading out the history of the amount and the rubbing distance and analyzing this data, the user's usage can be grasped in more detail.

Even when the specification of the process cartridge is changed, if the data stored in the storage means is changed, the optimum rotation speed of the contact charging member can be maintained without changing the image forming apparatus main body. .

Further, if the rotation control algorithm of the contact charging member is stored in the process cartridge, improved versions of the algorithm can be easily provided to the user one after another.
Customization for a specific user is also possible.

If there is room for the shaving amount (drum shaving amount) of the image carrier due to the usage of the user, the rotational speed of the contact charging member may be changed in accordance with the margin to widen the latitude of the charging uniformity. it can.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an internal structure of an embodiment of an image forming apparatus according to the present invention.

FIG. 2 is an external perspective view of the image forming apparatus shown in FIG.

FIG. 3 is a schematic cross-sectional view of a process cartridge according to the present invention.

FIG. 4 is an external perspective view of a process cartridge according to the present invention.

FIG. 5 is an external perspective view of the process cartridge according to the present invention (an external perspective model view in a state where the process cartridge is turned over and the drum shutter member is opened).

FIG. 6 is a schematic explanatory view showing a supporting configuration and a driving configuration of a charging roller and a photosensitive drum.

FIG. 7 is a schematic explanatory diagram of a control system.

FIG. 8 is a perspective view of a toner container for explaining a toner amount detection device according to the present invention.

FIG. 9 is a front view showing one embodiment of a measurement electrode member and a reference electrode member according to the present invention.

FIG. 10 is a front view showing another embodiment of the measurement electrode member and the reference electrode member according to the present invention.

FIG. 11 is a diagram illustrating a charging roller rotation speed changing method according to the first embodiment.

FIG. 12 is a diagram illustrating a charging roller rotation speed changing method according to a second embodiment.

FIG. 13 is a diagram illustrating a charging roller rotation speed changing method according to a third embodiment.

FIG. 14 is a block diagram of an electrophotographic image forming apparatus and a process cartridge according to the present invention.

FIG. 15 is a diagram illustrating a charging roller rotation speed changing method according to a fourth embodiment.

FIG. 16 is a first flowchart illustrating a control method according to a fourth embodiment.

FIG. 17 is a second flowchart illustrating the control method according to the fourth embodiment.

FIG. 18 is a third flowchart illustrating the control method according to the fourth embodiment.

FIG. 19 is a diagram illustrating a charging roller rotation speed changing method according to a fifth embodiment.

FIG. 20 is a diagram illustrating a charging roller rotation speed changing method according to a sixth embodiment.

FIG. 21 is a diagram illustrating a charging roller rotation speed changing method according to a sixth embodiment.

[Explanation of symbols]

A: Image forming apparatus (laser beam printer) B: Process cartridge C: Charging unit D: Developing unit L: Sliding distance LL: Sliding limit LA: Sliding predicted value L
E: rubbing distance error T: rotational drive time U: drum unit V: peripheral speed difference Va: peripheral speed of photosensitive drum Vb: peripheral speed of charging roller X: toner consumption XX: toner consumption limit n: rotation speed of charging roller DESCRIPTION OF SYMBOLS 1 ... Optical system 1a ... Laser diode 1b ... Polygon mirror 1c ... Lens 1d ... Reflection mirror 1e ... Exposure opening part 2 ... Recording medium 3 ... Conveying means 3a ... Paper feed cassette 3b ... Pickup roller 3c ... Conveyance roller pair 3d ... Conveyance port One pair
3e: registration roller pair 3f: conveyance guide 3g, 3
h, 3i: discharge roller pair 3j: reversal path 3k: flapper 3m: discharge roller pair 4: transfer port 5: fixing means 5a: heater 5b: fixing roller 5c
... Drive roller 6 ... Discharge tray 7 ... Photoreceptor drum 7d ... Inner diameter 7e ... Photosensitive layer 8 ... Charging roller 8a ... Core metal 9 ... Developing means 9b ... Toner feed member 9c ... Developing roller 9d ... Developing blade 9e ... Toner stirring member 9h …
Electrode rod 9k Developing roller gear 10 Cleaning means 10a Cleaning blade 10b Waste toner reservoir 11 Toner frame means 11A Toner container 12 Developing frame 13 Drum frame 13a Guide 13n Transfer opening 13k Press-fit inner diameter 14 ... Image forming apparatus main body 14a ... Frame 18 ... Drum shutter member 18a, 18b ... Guide 20 ... Toner amount detecting means 20A ... Measurement electrode member 20B ... Reference electrode member 22 ... Substrate 23 ... Input side electrode 24 ... Output side electrode 35 Opening / closing member 35a Shaft 36 Drum flange 36a Shaft portion 36d Convex portion 37 Drum flange 37a Gear 37b Fitting outer diameter portion 37d Fitting hole 39a Recess 39b Drive transmission shaft 40 Gear portion 50: storage means 100: drum shaft 100a: outer diameter portion 100b: shaft portion 10 c: tip surface 100d ... end surface 200 ... abutting member 201 ... bearing 202 ... compression coil spring 203 ... coupling member 300 ... bearing member 300a ... fitting inner diameter portion 500 ... drive transmission shaft 501 ... second drive motor (second drive means) ) 502: second drive control means 503: potential measurement means 600: first drive motor (first drive means) 601: first drive transmission shaft 601a: recess 602: first drive control means 611: read / write means 651 Control means 700: drum ground contact 700b: second contact 7
00c: 800 points contact base

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Etsuichi Sasako 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Toshiyuki Machiro 3-30-2 Shimomaruko, Ota-ku, Tokyo No. Canon F-term (reference) 2H027 DA45 DD02 DE04 DE07 EA01 ED03 EE03 EE08 EE10 EF06 EF09 HB02 HB15 2H071 AA42 BA04 BA13 BA32 BA33 BA34 CA07 DA06 DA08 DA15 DA31 2H200 FA02 FA20 GA23 GA34 GA15 GB60 HA29 HA30 HB12 HB17 HB22 LA29 LA36 PA11 PA18 PA24 PB23 PB34

Claims (42)

[Claims] 1. An image forming apparatus, comprising: a process cartridge including an image carrier, a charging member in contact with the image carrier, a detector for detecting a remaining amount of a developer, and a storage unit. A first driving unit for rotationally driving the image carrier, a second driving unit for rotationally driving the contact charging member, and a control unit for controlling a driving speed of the first driving unit and the second driving unit. An image forming apparatus, wherein the control unit controls a driving speed of the second driving unit based on a rotation speed of the second driving unit stored in the storage unit. 2. The image forming apparatus according to claim 1, wherein said control means stores said developer amount in said storage means when a remaining amount of developer or a consumed amount of developer detected by said detecting means reaches a predetermined value. An image forming apparatus that changes a driving speed of the second driving unit based on a rotation speed of the image forming apparatus. 3. The image forming apparatus according to claim 1, wherein said control means gradually increases the rotation speed of said second drive means as said developer consumption increases or said developer remaining amount decreases. An image forming apparatus characterized in that the image forming apparatus is controlled so as to be larger. 4. An image forming apparatus according to claim 1, further comprising a developing means for developing a latent image formed on said image carrier with a developer. 5. The image forming apparatus according to claim 4, wherein the developer of said developing means includes a toner and conductive charge-promoting particles, and said contact charging member forms a nip with said image carrier. An image forming apparatus, which is a plastic charging member, wherein a voltage is applied in a state where the charging promoting member is interposed between the charging member and the image carrier. 6. An image forming apparatus according to claim 1, wherein said image bearing member is a photosensitive member, and said contact charging member is a charging roller. 7. An image forming apparatus according to claim 1, wherein a program for controlling a driving speed of said second driving means is stored in said storage means. 8. An image forming apparatus, comprising: a process cartridge including an image carrier, a charging member for contacting the image carrier, a detecting unit for detecting a remaining amount of developer, and a storage unit. A first driving unit for rotationally driving the image carrier; a second driving unit for rotationally driving the contact charging member; controlling a driving speed of the first driving unit and the second driving unit; Control means for calculating a cumulative rubbing distance between the image carrier and the contact charging member; and the storage means stores the second rubbing distance corresponding to the cumulative rubbing distance.
An image forming apparatus, wherein one or more rotation speeds of a driving unit are stored, and the control unit controls a driving speed of the second driving unit based on the rotation speed stored in the storage unit. apparatus. 9. An image forming apparatus according to claim 8, wherein said control means is adapted to control when the remaining amount of developer or the amount of consumed developer detected by said detecting means reaches one or more predetermined values, respectively. An image forming apparatus that changes the driving speed of the second driving unit based on the number of rotations stored in the storage unit. 10. An image forming apparatus according to claim 8, wherein said control means gradually increases the rotation speed of said second drive means as said developer consumption increases or said developer remaining amount decreases. An image forming apparatus characterized in that the image forming apparatus is controlled so as to be larger. 11. An image forming apparatus according to claim 8, further comprising a developing means for developing a latent image formed on said image carrier with a developer. 12. An image forming apparatus according to claim 11, wherein said developer of said developing means includes toner and conductive charge-promoting particles, and said contact charging member is formed of a plastic material forming a nip portion with said image carrier. An image forming apparatus, wherein a voltage is applied in a state where the charging promoting member is interposed between the charging member and the image carrier. 13. An image forming apparatus according to claim 8, wherein said image bearing member is a photosensitive member, and said contact charging member is a charging roller. 14. An image forming apparatus according to claim 8, wherein a program for controlling a driving speed of said second driving means is stored in said storage means. 15. An image forming apparatus in which a process cartridge including an image carrier, a charging member in contact with the image carrier, a detector for detecting a remaining amount of a developer, and a memory is detachable. A first driving unit for rotationally driving the image carrier; a second driving unit for rotationally driving the contact charging member; controlling a driving speed of the first driving unit and the second driving unit; A control for calculating the cumulative rubbing distance between the image carrier and the contact charging member, and writing two or more of the calculated value and the remaining amount of developer or the amount of consumed developer detected by the detection unit to the storage unit. Means for controlling the number of rotations of the second driving means based on two or more of the accumulated rubbing distances stored in the storage means and the remaining amount of developer or the amount of consumed developer. And calculate
An image forming apparatus, wherein the second driving unit is controlled based on a calculated value. 16. An image forming apparatus according to claim 15, wherein the number of revolutions calculated by said control means is written in said storage means. 17. An image forming apparatus according to claim 15, wherein said control means is adapted to control when the remaining amount of developer or the amount of consumed developer detected by said detecting means reaches one or more predetermined values, respectively. An image forming apparatus that changes the driving speed of the second driving unit based on the number of rotations stored in the storage unit. 18. An image forming apparatus according to claim 15, wherein said control means controls the rotational speed of said second drive means in steps as said developer consumption increases or said developer remaining amount decreases. An image forming apparatus characterized in that the image forming apparatus is controlled so as to be larger in size. 19. An image forming apparatus according to claim 15, further comprising: developing means for developing a latent image formed on said image carrier with a developer. 20. An image forming apparatus according to claim 19, wherein the developer of said developing means includes a toner and conductive charge-promoting particles, and said contact charging member forms a nip with said image carrier. An image forming apparatus, which is a plastic charging member, wherein a voltage is applied in a state where the charging promoting member is interposed between the charging member and the image carrier. 21. The image forming apparatus according to claim 15, wherein said image bearing member is a photosensitive member, and said contact charging member is a charging roller. 22. The image forming apparatus according to claim 15, wherein a program for controlling a driving speed of said second driving means is stored in said storage means. 23. The image forming apparatus according to claim 15, wherein when the rotation speed calculated by the control means is smaller than a minimum value, the rotation speed is replaced with a minimum value, and the rotation speed is set to be smaller than a maximum value. An image forming apparatus characterized in that when the number of rotations is large, the number of rotations is replaced with a maximum value. 24. An image forming apparatus in which a process cartridge including an image carrier, a contact charging member for the image carrier, a detector for detecting an amount of developer, and a memory is detachably mountable. A first driving unit for rotationally driving the body, a second driving unit for rotationally driving the contact charging member, and a control unit for controlling the rotation of the first driving unit at a plurality of driving speeds, The control unit is configured to, when the driving speed of the first driving unit is changed, change the ratio of the driving speed of the first driving unit and the driving speed of the second driving unit to be the same. An image forming apparatus for controlling a driving speed of the image forming apparatus. 25. A first driving unit for rotating and driving the image carrier, a second driving unit for rotating and driving a contact charging member with respect to the image carrier, the first driving unit and the second driving unit. A process cartridge detachable from an image forming apparatus having a control unit for controlling a driving speed of the unit, the image carrier, a contact charging member for the image carrier, and a detection unit for detecting a remaining amount of a developer. And a storage unit for storing a number of revolutions for changing a driving speed of the second driving unit. 26. The process cartridge according to claim 25, wherein the drive speed of said second drive means is changed when the remaining amount of developer or the amount of developer consumed detected by said detection means reaches a predetermined value. And reading the rotation speed from the storage means. 27. A process cartridge according to claim 25, further comprising a developing means for developing a latent image formed on said image carrier with a developer. 28. The process cartridge according to claim 27, wherein the developer of said developing means includes toner and conductive charge-promoting particles, and said contact charging member is formed of a plastic material forming a nip portion with said image carrier. Wherein the voltage is applied in a state where the charging promoting member is interposed between the charging member and the image bearing member. 29. The process cartridge according to claim 25, wherein said image bearing member is a photosensitive member, and said contact charging member is a charging roller. 30. A process cartridge according to claim 25, wherein said storage means is a rewritable nonvolatile storage medium. 31. A first driving means for rotating and driving the image carrier, a second driving means for rotating and driving a contact charging member with respect to the image carrier, the first driving means and the second driving means. A cartridge that can be attached to and detached from an image forming apparatus having control means for controlling a driving speed of a unit and calculating a cumulative rubbing distance between the image bearing member and the contact charging member; A contact charging member for the carrier, a detecting unit for detecting a remaining amount of the developer, and a storage for storing one or more rotation speeds corresponding to the cumulative rubbing distance for controlling a driving speed of the second driving unit. A process cartridge comprising means. 32. The cartridge according to claim 31, wherein the drive speed of the second drive means is set when the remaining amount of the developer or the consumption amount of the developer detected by the detection means reaches one or more predetermined values. Wherein the number of revolutions is read from the storage means in order to change the number of rotations. 33. A process cartridge according to claim 31, further comprising a developing means for developing a latent image formed on said image carrier with a developer. 34. The process cartridge according to claim 33, wherein the developer of said developing means includes toner and electrically conductive charge-promoting particles, and said contact charging member is formed of a plastic material forming a nip with said image carrier. Wherein the voltage is applied in a state where the charging promoting member is interposed between the charging member and the image bearing member. 35. The process cartridge according to claim 31, wherein said image bearing member is a photosensitive member, and said contact charging member is a charging roller. 36. A first driving unit for rotating and driving the image carrier, a second driving unit for rotating and driving a contact charging member with respect to the image carrier, the first driving unit and the second driving unit. A cartridge which is detachable from an image forming apparatus having control means for controlling a driving speed of a unit and calculating a cumulative rubbing distance between the image carrier and the contact charging member, wherein the image carrier and the image A contact charging member for the carrier; a detecting unit for detecting a remaining amount of the developer; and a storage unit for storing two or more of the cumulative rubbing distance and the remaining amount of the developer or the consumed amount of the developer. A process cartridge. 37. The cartridge according to claim 36, wherein when the remaining amount of developer or the amount of consumed developer detected by the detection means reaches one or more predetermined values, the storage means stores the first and second values in the storage means. A process cartridge in which the number of revolutions of the second driving means for changing the driving speed of the second driving means is written. 38. The process cartridge according to claim 36, further comprising developing means for developing a latent image formed on said image carrier with a developer. 39. The process cartridge according to claim 38, wherein the developer of said developing means includes toner and conductive charge-promoting particles, and said contact charging member is formed of a plastic material forming a nip with said image carrier. Wherein the voltage is applied in a state where the charging promoting member is interposed between the charging member and the image bearing member. 40. The process cartridge according to claim 31, wherein said image bearing member is a photosensitive member, and said contact charging member is a charging roller. 41. An image carrier, a charging member in contact with said image carrier, storage means for storing data corresponding to the remaining amount of developer, and:
An image forming apparatus comprising: the image carrier; and control means for variably controlling a peripheral speed of the contact charging member. 42. An image bearing member, a contact charging member for said image bearing member, a storage means for storing data corresponding to the amount of developer used, and a cumulative friction between said image bearing member and said contact charging member. An image forming apparatus comprising: a control unit that calculates a distance and variably controls a peripheral speed of the image carrier and the contact charging member according to the calculated value and data stored in the storage unit.