JP2000181327A - Process cartridge and electrophotographic image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to nearly constantly maintain the rotating speed of an electrostatic charging means even if the friction force between an electrophotographic photoreceptor and the electrostatic charging means degrades by disposing a driving means for rotationally driving the electrostatic charging means in addition to the friction force with the surface of the electrophotographic photoreceptor. SOLUTION: A photosensitive drum 7 is rotatably held at a cleaning frame 13 by a drum shaft 7c. An electrostatic charging roller 8 is meshed with the electrostatic charging roller drive gear 7b of the photosensitive drum 7 in the electrostatic charging roller gear 8 a and, therefore, the electrostatic charging roller 8 is automatically rotted as well when the photosensitive drum 7 rotates. Springs 25 energize bearings 24 toward the photosensitive drum 7 side and press the surface of the electrostatic charging roller 8 toward the surface of the photosensitive drum 7 and, therefore, the friction force is generated between the surface of the photosensitive drum 7 and the surface of the electrostatic charging roller 8 when the photosensitive drum 7 rotates. The rotation is, therefore, imparted to the electrostatic charging roller 8 by the friction force with the surface of the photosensitive drum 7, by which the electrostatic charging roller is rotated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a process cartridge and an electrophotographic 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 printer, an LED printer, and the like), a facsimile machine, a word processor, and the like.

[0003] A process cartridge is different from the process cartridge in that a charging means, a developing means or a cleaning means, and an electrophotographic photosensitive member are integrally formed into a cartridge, and this cartridge is detachably mountable to an image forming apparatus main body. It is assumed that. In addition, the charging means, at least one of the developing means and the cleaning means, and the electrophotographic photosensitive member are integrally formed as a cartridge so as to be detachable from the image forming apparatus main body. Further, it refers to a device in which at least the charging means and the electrophotographic photosensitive member are formed into a cartridge so as to be detachable from the image forming apparatus main body.

[0004]

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

Such a process cartridge is provided with a charging means for charging the electrophotographic photosensitive member. As the charging means, there are a charging wire using corona discharge, a charging roller using contact charging, and the like. In recent years, a charging roller using contact charging has been widely used in consideration of environment such as ozone-less. The charging roller is configured to charge the electrophotographic photosensitive member while being rotated by a frictional force with the surface of the electrophotographic photosensitive member.

[0006]

SUMMARY OF THE INVENTION The present invention is a further development of the above-mentioned prior art, and its main purpose is to reduce the frictional force between the electrophotographic photosensitive member and the charging means even if the frictional force is reduced. It is an object of the present invention to provide a process cartridge capable of maintaining a substantially constant rotation speed, and an electrophotographic image forming apparatus to which the process cartridge can be attached and detached.

Another main object is to prevent the charging means and the microscopic sliding of the surface of the electrophotographic photosensitive member which occur in the initial use state of the process cartridge, prevent the surface of the electrophotographic photosensitive member from being scraped, and prevent the electrophotographic photosensitive member from being scraped. It is an object of the present invention to provide a process cartridge capable of extending the durability life of an image forming apparatus, and an electrophotographic image forming apparatus to which the process cartridge can be attached and detached.

[0008]

A typical configuration for achieving the above object is as follows: (1) An electrophotographic photosensitive member, a process cartridge detachable from an electrophotographic image forming apparatus main body, and the electrophotographic photosensitive member. Charging means for charging the electrophotographic photosensitive member while being rotated by frictional force with the surface of the electrophotographic photosensitive member in contact with the surface of the electrophotographic photosensitive member; and And a driving member for rotationally driving the process cartridge.

(2) An electrophotographic image forming apparatus for detachably attaching a process cartridge to form an image on a recording medium, comprising: a) an electrophotographic photosensitive member, and the electrophotographic photosensitive member in contact with a surface of the electrophotographic photosensitive member. A charging unit for charging the electrophotographic photosensitive member while being rotated by a frictional force with the surface of the photographic photosensitive member; and a driving unit for rotating the charging unit in addition to the frictional force with the surface of the electrophotographic photosensitive member. An electrophotographic image forming apparatus, comprising: mounting means for detachably mounting a process cartridge having a member; and b) transport means for transporting the recording medium.

(3) In a process cartridge detachable from the main body of the electrophotographic image forming apparatus, the electrophotographic photosensitive member is brought into contact with the surface of the electrophotographic photosensitive member and rotated by frictional force between the electrophotographic photosensitive member and the surface of the electrophotographic photosensitive member. Charging means for charging the electrophotographic photosensitive member while being rotated, a driving member for rotating the charging means in addition to the frictional force with the surface of the electrophotographic photosensitive member, and a charging means by the driving member. And a clutch mechanism for interrupting the transmission of the rotational driving force.

(4) An electrophotographic image forming apparatus for detachably attaching a process cartridge to form an image on a recording medium, comprising: a) an electrophotographic photosensitive member; and an electrophotographic photosensitive member in contact with a surface of the electrophotographic photosensitive member. A charging unit for charging the electrophotographic photosensitive member while being rotated by a frictional force with the surface of the photographic photosensitive member; and a driving unit for rotating the charging unit in addition to the frictional force with the surface of the electrophotographic photosensitive member. Mounting means for removably mounting a process cartridge having a member and a clutch mechanism for interrupting transmission of a rotational driving force to the charging means by the driving member; and b) transporting the recording medium. And an electrophotographic image forming apparatus.

(Operation) In the process cartridge of (1) and the electrophotographic image forming apparatus of (2), even if the frictional force between the electrophotographic photosensitive member and the charging means is reduced, the charging is performed by the driving member. The means can be rotationally driven. Thereby, the rotation speed of the charging means can be kept substantially constant.

In the process cartridge of (3) and the electrophotographic image forming apparatus of (4), in the initial state of use of the process cartridge, the clutch mechanism temporarily transmits the rotational driving force to the charging means by the driving member. In other words, a slight slippage of the charging means and the surface of the electrophotographic photosensitive member is prevented. As a result, the surface of the electrophotographic photoreceptor can be prevented from being scraped, and the durability life of the electrophotographic photoreceptor can be extended.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment An embodiment of the present invention will be described below with reference to the drawings.

In the following description, for each member of the process cartridge, the longitudinal direction is a direction (substantially orthogonal) that intersects with the direction in which the process cartridge is attached to and detached from the main body of the electrophotographic image forming apparatus. It is parallel and intersects (substantially orthogonal) with the transport direction of the recording medium
Direction.

First, a laser beam printer as an electrophotographic image forming apparatus to which an embodiment of the present invention is applied will be described with reference to FIGS.

As an order of the description, first, the schematic structures of the electrophotographic image forming apparatus and the process cartridge will be described.

(Schematic Configuration of Electrophotographic Image Forming Apparatus and Process Cartridge) As shown in FIG. 2, this electrophotographic image forming apparatus (laser beam printer) A uses a recording medium (for example, recording paper) by an electrophotographic image forming process. , OHP sheet, cloth, etc.) 2. Then, a toner image (developer image) is formed on a drum-shaped electrophotographic photosensitive member (hereinafter, referred to as “photosensitive drum”) 7. More specifically, the photosensitive drum 7 is charged by the charging means 8, and then an electrostatic latent image is formed on the photosensitive drum 7 from the optical means 1 according to the image information. The 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 cassette 3a is reversely conveyed by the conveying means 3 including the pickup roller 3b, the conveying roller pairs 3c and 3d, the registration roller pair 3e, and the like. Next, the toner image formed on the photosensitive drum 7 of the process cartridge B is transferred to the recording medium 2 by applying a voltage to a transfer roller 4 as a transfer unit.

Further, the recording medium 2 after the transfer of the toner image is conveyed to the fixing means 5 while being guided by the guide member 3f. The fixing unit 5 includes a fixing roller 5b having a built-in heater 5a,
And a drive roller 5c for conveying the recording medium 2 by pressing the recording medium 2 against the fixing roller 5b. 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 discharge roller pair 3
g, 3h, and 3i, and is discharged to a discharge unit (discharge tray) 6 through a reverse transfer path 3j. As for the discharge, it is also possible to operate the swingable flapper 3k and discharge the recording medium 2 by the discharge roller pair 3m without passing through the reverse conveyance path 3j. In the present embodiment, the pickup roller 3b, the transport roller pair 3c, 3d, the registration roller pair 3e, the guide member 3
f, discharge roller pair 3g, 3h, 3i and reverse transport path 3
The transport means 3 is constituted by j.

On the other hand, in the process cartridge B, as shown in FIGS. 4 and 5, a photosensitive drum 7 having a photosensitive layer is rotated, and its surface is made uniform by applying a voltage to a charging roller 8 serving as a charging means. Charge. Then the optical means 1
A light image corresponding to image information from the exposure opening (not shown)
And irradiates the photosensitive drum 7 via the photoreceptor drum 7 to form an electrostatic latent image. Then, the latent image is developed by developing means 9 using toner as a developer. That is, the charging roller 8 is provided in contact with the photosensitive drum 7 and charges the photosensitive drum 7. The charging roller 8 is driven and rotated by the photosensitive drum 7. The developing means 9 supplies toner to the developing area of the photosensitive drum 7 to
Is developed. Optical means 1
Has a laser diode (not shown), a polygon mirror 1a, a lens 1b, and a reflection mirror 1c. The rotating polygon mirror 1a scans the image light emitted from the laser diode according to the image information with the rotating polygon mirror 1a.
Photoconductor drum 7 via lens 1b and reflection mirror 1c
To form an electrostatic latent image on the photosensitive drum 7.

Here, the developing means 9 causes the toner in the toner storage portion 9a to rotate by rotating the toner feeding member 9b.
It is sent to the developing roller 9c. Then, the developing roller 9c containing the fixed magnet is rotated and the developing blade 9c is rotated.
The toner layer provided with the triboelectric charge by d is formed on the surface of the developing roller 9c. Then, the toner image is transferred to the photosensitive drum 7 in accordance with the latent image, thereby forming a toner image and visualizing the toner image.

After the toner image is transferred to the recording medium 2 by applying a voltage having a polarity opposite to that of the toner image to the transfer roller 4, the toner remaining on the photosensitive drum 7 is scraped off and removed by the cleaning blade 10a. The cleaning unit 10 that collects the toner in the toner reservoir 10b removes the residual toner on the photosensitive drum 7, and prepares for the next step.

In the process cartridge B, a developing container 12 is formed by connecting a toner container 11 for storing toner and a developing container 23 for holding the developing means 9 such as a developing roller 9c. The photosensitive drum 7, the cleaning means 10 such as the cleaning blade 10a, and the cleaning frame 13 to which the charging roller 8 is attached are combined with the photosensitive drum 7,
A housing as a cartridge frame is formed.
The process cartridge B is removably mounted on the cartridge device means provided on the apparatus main body 14 by an operator.

Next, a structure in which the process cartridge B can be attached to and detached from the apparatus main body 14 will be described with reference to FIGS.

(Structure of Cartridge Mounting Member and Guide Member) As shown in FIGS. 2 and 3, when the opening / closing member 15 provided at the top of the apparatus main body 15 so as to be openable and closable is rotated counterclockwise and opened. 6 and 7, a cartridge mounting space S appears. In the cartridge mounting space S, a cartridge mounting member 16 as a cartridge mounting means is mounted on the left and right inner surfaces of the apparatus main body A. The left and right guide members 16 are provided with concave guide portions 16a for inserting the process cartridges B facing each other.

On both outer side surfaces in the longitudinal direction of the process cartridge B, there are provided convex guide means 17 serving as guides for attaching and detaching the process cartridge B to / from the apparatus main body 14. As shown in FIG. 5, the guide means 17 includes a cylindrical guide 17a as a positioning guide,
Non-rotating guide 17 as a guide for holding posture when attaching / detaching
b. Although only one guide means is shown in FIG. 5, a cylindrical guide and a detent guide (not shown) are provided on the opposite side.

To mount the process cartridge B on the apparatus main body 14, the cylindrical guide 17a and the detent guide 17b of the process cartridge B are fitted into the guide section 16a of the apparatus main body 14, and then the process cartridge B is connected to the guide section. Insert in the direction of arrow X (see FIG. 1) along 16a. At this time, the cylindrical guide 17a and the detent guide 17
b is guided to the back side along the guide portion 16a, and the cylindrical guide 17a is seated on the back portion (positioning portion) of the guide portion 16a, and the mounting position of the process cartridge B to the apparatus main body 14 is determined. Then, by closing the opening / closing member 15, the mounting of the process cartridge B on the apparatus main body 14 is completed.

To remove the process cartridge B from the apparatus main body 14, the opening and closing member 15 of the apparatus main body 14 is opened and the process cartridge B is guided to the guide portion 16a.
Along the arrow X direction. At this time, the cylindrical guide 17a of the process cartridge B and the detent guide 1
7b moves through the guide portion 16a of the apparatus main body 14 and rises. And from the guide portion 16a to the detent guide 17b
The process cartridge B is taken out of the apparatus main body 14 by pulling out the cylindrical guide 17a.

Next, the structure of the housing of the process cartridge B will be described with reference to FIGS. 4, 5, 8 and 9.

(Structure of Housing of Process Cartridge) As described above, the process cartridge B according to the present embodiment forms a housing by connecting the developing frame 12 and the cleaning frame 13 to each other. The configuration will be described.

As shown in FIG. 4, the developing frame 12 comprises a toner container 11 and a developing container 23.

A toner container 9a is formed in the toner container 11, and a toner feeding member 9b is attached thereto. The developing container 23 includes a developing roller 9 c and a developing blade 9.
d, and a stirring member 9e for circulating the toner in the developing chamber near the developing roller 9c is rotatably mounted. The toner container 11 and the developing frame 12 are welded to form an integral developing unit TU.

The photosensitive drum 7, the charging roller 8, and the cleaning means 10 are attached to the cleaning frame 13, and the process cartridge B is further attached to the apparatus body 14.
The cleaning unit CU is configured by covering the photosensitive drum 7 when it is detached from the printer, and attaching a drum shutter member 18 for protecting the photosensitive drum 7.

Then, the process cartridge B is constituted by connecting the developing unit TU and the cleaning unit CU. For this purpose, cover members (not shown) that rotatably support both ends of the developing roller 9c are attached to both longitudinal sides of the developing frame body 12. As shown in FIGS. 8 and 9, a rotating shaft 20 is provided at the tip of the arm 19 formed on the cover member (FIGS. 8 and 9 show only one side). On the other hand, concave portions 21 for positioning the rotation shaft 20 are provided at two positions on both sides in the longitudinal direction of the cleaning frame 13. The rotating shaft 20 is inserted into the recess 21, and a coupling member 22 having a protrusion 22 a is provided.
Is screwed to the cleaning frame 13. This allows
The developing unit TU and the cleaning unit CU are rotatably connected around a rotation shaft 20, and the developing roller 9 c is pressed against the photosensitive drum 7 by the weight of the developing unit TU. At this time, the developing roller 9c is reliably pressed against the photosensitive drum 7 by urging the developing frame 12 downward by the compression spring 22b attached to the coupling member 22. Therefore, by attaching spacer rings (not shown) to both ends in the longitudinal direction of the developing roller 9c, this ring is pressed against the photosensitive drum 7, and the photosensitive drum 7 and the developing roller 9c face each other at a fixed interval.

(Configuration of Charging Roller) Next, the charging roller 8 of the process cartridge B according to the present embodiment will be described in more detail with reference to FIG.

In FIG. 1, reference numeral 7 denotes a photosensitive drum, and reference numeral 8 denotes a charging roller.

The charging roller 8 has a structure in which conductive rubber is fixed to a core shaft (hereinafter referred to as "shaft") 8b, and the surface thereof is provided with an insulating rubber, a tube, or the like. The charging roller 8 is rotatably held by the cleaning frame 13 via bearings 24 provided at both ends of the shaft 8b. The charging roller 8 is pressed against the surface of the photosensitive drum 7 by the urging force of a spring (compression spring) 25 provided between the bearing 24 and the projection 13a provided on the cleaning frame 13 so as to face the bearing 24. I have. The charging roller 8 has a charging roller gear 8a on one bearing 24 side. The charging roller gear 8a is mounted on a shaft 8b.

The photosensitive drum 7 is rotatably held on the cleaning frame 13 by a drum shaft 7c. The photosensitive drum 7 has a drive gear 7a at one end in the longitudinal direction. When the process cartridge B is mounted in the apparatus main body 14, the drive gear 7a is driven by a drive gear (not shown) of the apparatus main body 14. ) And a rotational driving force can be obtained. A charging roller driving gear 7b is provided at the other end of the photosensitive drum 7. The charging roller driving gear 7b is configured to mesh with the charging roller gear 8a of the charging roller 8 in a state where the process cartridge B is mounted in the apparatus main body 14.

In the charging roller 8 having such a configuration, the charging roller gear 8a is connected to the charging roller driving gear 7 of the photosensitive drum 7.
As the photosensitive drum 7 rotates, the charging roller 8 is also automatically rotated. Also spring 2
5 urges the bearing 24 toward the photosensitive drum 7 and presses the surface of the charging roller 8 against the surface of the photosensitive drum 7, so that when the photosensitive drum 7 rotates, the photosensitive drum 7
A frictional force is generated between the surface of the charging roller 8 and the surface of the charging roller 8. For this reason, the charging roller 8 is rotated by being given a rotational force by a frictional force with the surface of the photosensitive drum 7.

That is, the charging roller 8 of this embodiment is
The photosensitive drum 7 is pressed onto the photosensitive drum 7 and
AC and DC voltages are applied between the surface of the photosensitive drum 7 and the shaft 8b, so that the photosensitive drum 7 is simultaneously rotated while being rotated by the frictional force between the charging roller drive gear 7b of the photosensitive drum 7 and the surface of the photosensitive drum 7. 7 is charged.

The charging roller driving gear 7b of the photosensitive drum 7 and the charging roller gear 8a of the charging roller 8
The transmission rotation speed transmitted from the charging roller driving gear 7b to the charging roller gear 8a can be adjusted by appropriately setting the number of teeth and the outer diameter. As a result, charging is performed from the charging roller driving gear 7b of the photosensitive drum 7 at substantially the same rotational speed as that for rotating the charging roller 8 by the frictional force generated between the surface of the charging roller 8 and the surface of the photosensitive drum 7. The charging roller gear 8a of the roller 8 can be driven to rotate.

Therefore, while the image is formed on the recording medium 2 in the image forming apparatus A of the present embodiment, toner enters between the surface of the photosensitive drum 7 and the surface of the charging roller 8, and the photosensitive drum Even if the frictional force between the surface of the charging roller 8 and the surface of the charging roller 8 decreases, the photosensitive drum 7 and the charging roller 8 rotate at a substantially constant speed.

As a result, the photosensitive drum 7 caused by the insufficient rotation force being transmitted to the charging roller 8
Can be prevented from being charged poorly.

Embodiment 2 Next, a process cartridge B according to this embodiment will be described with reference to FIGS.

The process cartridge B of this embodiment is
The configuration is the same as that of the process cartridge B of the first embodiment except that the charging roller 8 includes the clutch mechanism 26. Therefore, as shown in FIG. 11, the photosensitive drum 7 is rotatably held by the cleaning frame 13 by the drum shaft 7c. The charging roller 8 is connected to the cleaning frame 1 via bearings 24 provided at both ends of the shaft 8b.
3 rotatably held. The charging roller 8 is pressed against the surface of the photosensitive drum 7 by the urging force of a spring (compression spring) 25 provided between the bearing 24 and the protruding piece 13a provided on the cleaning frame 13 so as to face the bearing 24. I have.

As shown in FIG. 10, the clutch mechanism 26 has a cap 28 as a fixed member fixed to the shaft 8b of the charging roller 8, and an elastic member for urging and pressing the charging roller gear 8a against the cap 28. A spring (compression spring) 27 and a cap 28 of the charging roller gear 8a
Plate 29 for interrupting transmission of rotational driving force to
And

The charging roller gear 8a is a shaft 8 of the charging roller 8.
b is rotatably attached to the end. The charging roller gear 8a has a hollow shaft portion 8a1 on the cap 28 side through which the shaft 8b of the charging roller 8 penetrates.
A flange portion 8a2 is provided at the tip of 1.

The cap 28 is fixed to the shaft 8 b of the charging roller 8 by a pin 30 so as to rotate integrally with the charging roller 8. The cap 28 has a concave space 28a that opens toward the charging roller gear 8a. A flange 8a2 is fitted into the space 28a so as to be movable in the axial direction of the shaft 8b through the hollow shaft 8a1 of the charging roller gear 8a.

The spring 27 is attached to the outer periphery of the hollow shaft portion 8a1 of the charging roller gear 8a. The spring 27 attaches the flange 8a2 of the charging roller gear 8a to the cap 28.
Of the charging roller gear 8a.

The clutch plate 29 is provided in the space 2 of the cap 28.
8a, it is provided between the locking portion 28b and the flange portion 8a2 of the charging roller gear 8a. By changing the material of the clutch plate 29, that is, the clutch plate 2
By replacing the clutch plate 9 with a clutch plate of another material, the magnitude of the transmitted rotational force (rotational driving force) transmitted from the charging roller gear 8a to the cap 28 can be adjusted.

As described in the first embodiment, the charging roller driving gear 7b of the photosensitive drum 7 and the charging roller gear 8a of the charging roller 8 are driven by appropriately setting the number of teeth and the outer diameter. It is possible to adjust the transmission rotation speed transmitted from the gear 7b to the charging roller gear 8a. As a result, the rotational speed (V1) is substantially the same as the rotational speed (V2) at which the charging roller 8 is driven to rotate by the frictional force generated between the surface of the charging roller 8 and the surface of the photosensitive drum 7.
Thus, the charging roller gear 8a of the charging roller 8 can be driven to rotate from the charging roller driving gear 7b of the photosensitive drum 7. However, there is a slight speed difference between the speeds V1 and V2.
The speeds V1 and V2 may not be constant due to eccentricity or the like.

Here, in the initial state of use of the process cartridge B, the relation of the forces acting on each member is, in descending order, the force for rotating the charging roller gear 8a of the charging roller 8 from the charging roller driving gear 7b of the photosensitive drum 7 (see FIG. F
2) The force (F1) for rotating and driving the charging roller 8 by the surface frictional force of the photosensitive drum 7 and the magnitude of the transmitting rotation force (F3) from the charging roller gear 8a to the charging roller 8 by the clutch mechanism 26 (F3). F2>F1> F3).

Therefore, when the photosensitive drum 7 is rotated in the initial use state of the process cartridge B,
The charging roller 8 is controlled by the speed V1 controlled by the force F2.
Rotate by. At this time, the speed difference between the speeds V1 and V2 is absorbed by the sliding of the charging roller gear 8a and the cap 28 of the clutch mechanism 26. More specifically, it is absorbed by the flange portion 8a2 of the charging roller gear 8a sliding on the clutch plate 29 in the cap 28 of the clutch mechanism 26. That is, the transmission of the rotational driving force to the cap 28 of the charging roller gear 8a is temporarily interrupted until the speed difference between the speeds V1 and V2 becomes zero. As a result, the speeds V1 and V2 become equal, and the surface of the photosensitive drum 7 and the surface of the charging roller 8 do not slip. As a result, the shaving of the surface of the photosensitive drum 7 can be minimized, and the durability life of the photosensitive drum 7 can be extended.

Thereafter, as the image is formed on the recording medium 2, toner enters between the surface of the photosensitive drum 7 and the surface of the charging roller 8, and the surface of the photosensitive drum 7 and the surface of the charging roller 8 The frictional force between the two decreases. in this case,
When the magnitudes of the forces F1 and F3 are reversed, the charging roller 8
Is forcibly rotated at the speed V1. At this time, the slight speed difference between the speeds V1 and V2 is absorbed by slipping between the surface of the photosensitive drum 7 and the surface of the charging roller 8, that is, slipping of the charging roller gear 8a and the cap 28 of the clutch mechanism 26. However, since the frictional force between the surface of the photoconductor drum 7 and the surface of the charging roller 8 is reduced, the amount of the surface of the photoconductor drum 7 that can be shaved is small.

[Other Embodiments] The electrophotographic photosensitive member of the process cartridge shown in the above-mentioned embodiment is not limited to the photosensitive drum, but includes, for example, the following. First, a photoconductor is used as a photoconductor, and examples of the photoconductor include amorphous silicon, amorphous selenium, zinc oxide, titanium oxide, and an organic photoconductor (OPC). As the shape on which the photoconductor is mounted, for example, a drum-shaped or belt-shaped one is used. For example, in the case of a drum-type photoconductor, a photoconductor is deposited or coated on a cylinder made of an aluminum alloy or the like. It has been worked.

Various developing methods such as a known two-component magnetic brush developing method, a cascade developing method, a touch-down developing method, and a cloud developing method can be used as the developing method.

The above-described process cartridge includes, for example, an electrophotographic photosensitive member and at least one of processing means. Therefore, as an aspect of the process cartridge, in addition to the above-described embodiment, for example, an electrophotographic photosensitive member and a charging unit are integrally formed into a cartridge and can be attached to and detached from the apparatus main body. An electrophotographic photosensitive member, a charging unit, and a developing unit are integrally formed into a cartridge, which is detachable from the apparatus main body. There is an electrophotographic photosensitive member, a charging unit, and a cleaning unit which are integrally formed into a cartridge, which is detachably mountable to an apparatus main body.

That is, the above-described process cartridge includes a charging unit, a developing unit or a cleaning unit,
The electrophotographic photosensitive member and the electrophotographic photosensitive member are integrally made into a cartridge, and this cartridge is made detachable from the image forming apparatus main body. In addition, the charging means, at least one of the developing means and the cleaning means, and the electrophotographic photosensitive member are integrally formed as a cartridge so that the cartridge can be detachably attached to the image forming apparatus main body. Further, at least the charging means and the electrophotographic photoreceptor are formed into a cartridge so as to be detachable from the image forming apparatus main body. The process cartridge can be attached to and detached from the apparatus main body by the user himself. Therefore, the maintenance of the apparatus main body can be performed by the user himself.

[0061]

As described above, according to the process cartridge and the electrophotographic image forming apparatus of the present invention, even if the frictional force between the electrophotographic photosensitive member and the charging means is reduced, the rotation speed of the charging means is substantially reduced. Can be kept constant.

Further, the charging means and the microscopic sliding of the surface of the electrophotographic photosensitive member, which are generated in the initial use state of the process cartridge, are prevented, so that the surface of the electrophotographic photosensitive member is prevented from being scraped and the durability life of the electrophotographic photosensitive member is extended. be able to.

[Brief description of the drawings]

FIG. 1 is a top view of a charging roller of a process cartridge according to a first embodiment.

FIG. 2 is an overall configuration diagram illustrating an example of an electrophotographic image forming apparatus to which the process cartridge according to the first embodiment is mounted.

FIG. 3 is a perspective view of the electrophotographic image forming apparatus as viewed from the outside.

FIG. 4 is a sectional view illustrating a configuration of a process cartridge.

FIG. 5 is a perspective view of the process cartridge as viewed from the outside.

FIG. 6 is a perspective view illustrating a cartridge mounting portion on the left side of the main body of the electrophotographic image forming apparatus.

FIG. 7 is a perspective view showing a cartridge mounting portion on the right side of the main body of the electrophotographic image forming apparatus.

FIG. 8 is an enlarged view of a portion where the developing unit and the cleaning of the process cartridge are combined.

FIG. 9 is a cross-sectional view of a combined portion of the developing unit and the cleaning of the process cartridge.

FIG. 10 is a cross-sectional view illustrating a coupling relationship between a clutch mechanism provided on a charging roller of a process cartridge according to a second embodiment and a charging roller gear.

FIG. 11 is a top view of a charging roller of the process cartridge according to the second embodiment.

[Explanation of symbols]

 3 Conveying Means 7 Electrophotographic Photoreceptor 8 Charging Roller (Charging Means) 8a Charging Roller Gear (Drive Member) 9 Developing Means 10 Cleaning Means 14 Electrophotographic Image Forming Apparatus Main Body 16 Guide Member (Mounting Means) 26 Clutch Mechanism A Electrophotographic Image Forming Device B Process cartridge

Claims (6)

[Claims] A process cartridge detachable from a main body of the electrophotographic image forming apparatus, wherein the process cartridge is rotated by frictional force between the electrophotographic photosensitive member and the surface of the electrophotographic photosensitive member in contact with the surface of the electrophotographic photosensitive member. A charging unit for charging the electrophotographic photosensitive member while rotating the charging unit in addition to a frictional force with the surface of the electrophotographic photosensitive member. . 2. A process cartridge detachable from the main body of an electrophotographic image forming apparatus, wherein the process cartridge is rotated by frictional force between the electrophotographic photoconductor and the surface of the electrophotographic photoconductor in contact with the surface of the electrophotographic photoconductor. A charging unit for charging the electrophotographic photosensitive member while rotating the charging unit in addition to a frictional force with the surface of the electrophotographic photosensitive member; and a driving member for rotating the charging unit by the driving member. A process cartridge, comprising: a clutch mechanism for interrupting transmission of rotational driving force. 3. The apparatus according to claim 1, wherein the driving member is a gear, and a driving force is directly transmitted from the electrophotographic photosensitive member and the charging unit rotated by a frictional force between the electrophotographic photosensitive member and a surface of the electrophotographic photosensitive member. The process cartridge according to claim 1, wherein: 4. The process cartridge includes a developing unit for developing an electrostatic latent image formed on the electrophotographic photosensitive member with a developer and a developing unit for removing a developer remaining on the electrophotographic photosensitive member. 3. The electrophotographic image forming apparatus according to claim 1, wherein at least one of the cleaning means, the electrophotographic photoreceptor, and the charging means are integrally formed into a cartridge so that the cartridge can be attached to and detached from the electrophotographic image forming apparatus main body. The process cartridge according to 1. 5. An electrophotographic image forming apparatus for detachably attaching a process cartridge and forming an image on a recording medium, comprising: a) an electrophotographic photosensitive member; and an electrophotographic photosensitive member in contact with a surface of the electrophotographic photosensitive member. A charging unit that charges the electrophotographic photosensitive member while being rotated by a frictional force with the surface of the photoreceptor; and a driving member that rotationally drives the charging unit in addition to the frictional force with the surface of the electrophotographic photosensitive member. An electrophotographic image forming apparatus, comprising: mounting means for removably mounting a process cartridge having: (b) conveying means for conveying the recording medium. 6. An electrophotographic image forming apparatus for detachably attaching a process cartridge and forming an image on a recording medium, comprising: a) an electrophotographic photosensitive member; and an electrophotographic photosensitive member in contact with a surface of the electrophotographic photosensitive member. A charging unit that charges the electrophotographic photosensitive member while being rotated by a frictional force with the surface of the photoreceptor; and a driving member that rotationally drives the charging unit in addition to the frictional force with the surface of the electrophotographic photosensitive member. Mounting means for detachably mounting a process cartridge having a clutch mechanism for interrupting transmission of rotational driving force to the charging means by the driving member; and b) transporting the recording medium. An electrophotographic image forming apparatus, comprising: transport means.