JP2000356939A - Process cartridge and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent wear, deformation and damage of clearance forming members which form a clearance between a photoreceptor drum and a developing sleeve and to obtain a stable image output. SOLUTION: First clearance forming members 103a and 103b are provided on the same axis as a photoreceptor drum 7, and also second clearance forming members 106a and 106b which are in contact with the first clearance forming members 103 are provided on the same axis as a developing sleeve 9c. The outside diameter of the first clearance forming members 103a and 103b and second clearance forming members 106a and 106b is determined so that they can rotate without causing slip of contact parts of them.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process cartridge detachable from an electrophotographic image forming apparatus.

Here, an 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 an electrophotographic copying machine, an electrophotographic printer (for example, a laser printer), a facsimile machine, and a word processor.

[0003]

2. Description of the Related Art Conventionally, in an image forming apparatus using an electrophotographic image forming process provided with this type of process cartridge, an electrophotographic photosensitive member and process means acting on the electrophotographic photosensitive member are integrally formed as a cartridge. A process cartridge that allows the lever cartridge to be attached to and detached from the image forming apparatus main body is employed.

[0004] A process cartridge is provided with a photosensitive drum for electrophotography and at least one of processing means. That is, at least one of the charging unit, the developing unit, and the cleaning unit and the electrophotographic photosensitive member are integrally formed as a cartridge so that the cartridge can be attached to and detached 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, and the maintenance of the apparatus main body can be performed by the user himself. Therefore, according to this process cartridge system, the maintenance of the apparatus can be performed by the user himself without relying on a service person, so that usability is remarkably improved.

FIG. 6 shows a two-frame structure as a typical structure of such a process cartridge. Here, C is a cleaner unit that supports the photosensitive drum 7, and D is a developing frame having a developing sleeve 9c and a toner container 11. The developing frame D is rotatably supported around a fulcrum shaft 22, and is urged clockwise in the figure by a coil spring 22a.

On the other hand, in order to obtain stable image quality in an electrophotographic image process, it is necessary to maintain a constant clearance between the photosensitive drum 7 and the developing sleeve 9c. As this means, a method using an SD roller 200 shown in FIG. 7 is generally used. The SD roller 200 is a thin cylindrical resin part, and is fitted to both ends of the developing sleeve 9c. By bringing this into contact with the photosensitive drum 7, the clearance between the surface of the photosensitive drum 7 and the surface of the developing sleeve 9c can be maintained by the thickness of the SD roller 200 managed.

With the above arrangement, the photosensitive drum 7 and the developing sleeve 9c in the process cartridge having a two-frame structure are provided.
, And the clearance between the surface of the photosensitive drum 7 and the surface of the developing sleeve 9c can be maintained.

[0008]

However, the configuration for maintaining the clearance between the surface of the photosensitive drum 7 and the surface of the developing sleeve 9c using the conventional SD roller 200 has the following problems to be solved.

1. Function deterioration such as image deterioration due to rubbing wear of the SD roller 200.

[0010] 2. Functional deterioration such as image deterioration due to a change in clearance due to deformation of the SD roller 200 and deformation of a contacting part (drum, sleeve) that comes into contact.

The present invention has been made to solve the above-mentioned problems of the prior art.
Photosensitive drum 7 and developing sleeve 9c due to rubbing wear and deformation
It is an object of the present invention to provide a process cartridge and an image forming apparatus that can stably maintain a constant clearance by preventing a change in clearance therebetween.

[0012]

According to a first aspect of the present invention, there is provided a first frame unit having a photosensitive drum and a first sleeve unit having a developing sleeve. A second frame unit rotatably supported with respect to the photosensitive drum and the developing sleeve; and a gap forming means for forming a predetermined gap between the photosensitive drum and the developing sleeve. A biasing means for biasing the photosensitive drums against each other, wherein the gap forming means is provided on both ends of the photosensitive drum coaxially with a first gap forming member;
A second gap forming member provided on both ends of the developing sleeve coaxially with the developing sleeve, wherein the first gap forming member and the second gap forming member are in contact with each other at their outer diameters; Is given by ωD, and the outer diameter dCD of the first gap member and the outer diameter dCS of the second gap member are given by ωD × dCD = ωS × dCS (1) And the outer diameter of the photosensitive drum is set to dDRU.
M, when the outer diameter of the developing sleeve is dSLV and the gap is given by C, dCD + dCS = dDRUM + dsLV + 2C (2).

A first gap forming member is provided coaxially with the photosensitive drum at both ends of the photosensitive drum, and a clearance forming member is provided coaxially with the developing sleeve at both ends of the developing sleeve.

The outer diameters of these two first and second gap forming members are precisely controlled, and as a result of contact with each other, the gap between the photosensitive drum surface and the developing sleeve can be maintained at a predetermined value. It is possible.

Here, when the angular velocity ωD of the photosensitive drum and the angular velocity of the developing sleeve are given by ωS, respectively, the outer diameter dCD of the first gap forming member and the outer diameter dCS of the second gap forming member are given.
Is determined so as to satisfy the relations of the above expressions (1) and (2), the clearance members that come into contact with each other do not slip at the contact points (the peripheral speed is the same), so that the abrasion due to the rubbing can be prevented.

The invention according to claim 2 is characterized in that the first gap forming member provided coaxially with the photosensitive drum cannot rotate with respect to the photosensitive drum.

When the first gap forming member is not rotatable with respect to the photosensitive drum, the outer diameter of the photosensitive drum and the outer diameter of the first gap forming member can be simultaneously processed. The clearance between the sleeves can be maintained with high precision.

The invention according to claim 3 is characterized in that the first gap forming member provided coaxially with the photosensitive drum is rotatable with respect to the photosensitive drum.

When the rotation speed of the photosensitive drum and the rotation speed of the developing sleeve fluctuate when the first gap forming member is rotatable with respect to the photosensitive drum, the relative speed is used as the photosensitive speed of the first gap forming member. Since it can be absorbed by rotation with respect to the drum, the first and second
Wear of the clearance forming member can be prevented.

The invention according to a fourth aspect is characterized in that the second gap forming member provided coaxially with the developing sleeve cannot rotate with respect to the developing sleeve.

When the second gap forming member cannot rotate with the developing sleeve, the outer diameter portion of the developing sleeve and the outer diameter portion of the second gap forming member can be simultaneously processed. The clearance between the sleeves can be maintained with high precision.

According to a fifth aspect of the present invention, the second gap forming member provided coaxially with the developing sleeve is rotatable with respect to the developing sleeve.

When the rotational speed of the photosensitive drum and the rotational speed of the developing sleeve fluctuate, the relative speed can be absorbed by the rotation of the second gap forming member with respect to the developing sleeve. Wear of the second gap forming member can be prevented.

The invention according to claim 6 is characterized in that the first gap forming member provided coaxially with the photosensitive drum has an integral structure with drum flanges provided at both ends of the photosensitive drum cylinder.

When the first gap forming member is integrally formed with the photosensitive drum, the outer diameter of the photosensitive drum and the outer diameter of the first gap forming member can be simultaneously processed in addition to facilitating assembly. The clearance between the photosensitive drum and the developing sleeve can be maintained with high accuracy.

The invention according to claim 7 is characterized in that the second gap forming member provided coaxially with the developing sleeve has an integral structure with sleeve flanges provided at both ends of the developing sleeve.

When the second gap forming member is integral with the developing sleeve, the outer diameter of the developing sleeve and the outer diameter of the second gap forming member can be simultaneously processed in addition to facilitating assembly. The clearance between the photosensitive drum and the developing sleeve can be maintained with high accuracy.

The invention according to claim 8 is characterized in that the process cartridge according to any one of claims 1 to 7 is detachably mounted to the image forming apparatus main body.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the illustrated embodiments. In the following description, the short direction of the process cartridge B refers to the direction in which the process cartridge B is attached to and detached from the electrophotographic image forming apparatus main body (hereinafter, referred to as the image forming apparatus main body or the apparatus main body) 14. With the transport direction of Also,
The longitudinal direction of the process cartridge B is a direction crossing (substantially orthogonal to) the direction in which the process cartridge B is attached to and detached from the apparatus main body 14, parallel to the surface of the recording medium, and the conveying direction of the recording medium 2. The direction intersects (substantially orthogonal). Further, regarding the process cartridge B,
The left and right are right or left when the recording medium 2 is viewed from above according to the transport direction of the recording medium 2.

FIG. 2 is an explanatory view of the configuration of an electrophotographic image forming apparatus (laser beam printer) to which the embodiment of the present invention is applied, and FIG. 3 is an external perspective view thereof. 4 and 5
4 is a drawing relating to a process cartridge to which an embodiment of the present invention is applied, FIG. 4 is a side sectional view of a process cartridge B, and FIG. 5 is an external perspective view schematically showing the external appearance thereof.

In the following description, the upper surface of the process cartridge B is a surface located above when the process cartridge B is mounted on the apparatus main body 14, and the lower surface is a surface located below.

(Schematic Configuration of Electrophotographic Image Forming Apparatus A and Process Cartridge B) First, referring to FIGS. 2 and 3, a laser beam printer A as an electrophotographic image forming apparatus to which an embodiment of the present invention is applied. explain.

As shown in FIG. 2, the laser beam printer A forms an image on a recording medium 2 (for example, recording paper, OHP sheet, cloth, etc.) by an electrophotographic image forming process. Then, a toner image is formed on a drum-shaped electrophotographic photosensitive member (hereinafter, referred to as photosensitive drum 7). Specifically, the photosensitive drum 7 is charged by a charging roller 8 serving as a charging unit, and then the photosensitive drum 7 is irradiated with laser light corresponding to image information from the optical unit 1 to the photosensitive drum 7 in accordance with the image information. Form a latent image. The latent image is developed by the developing means 9 to form a toner image. Then, in synchronization with the formation of the toner image, the recording medium 2 set in the sheet feeding cassette 3a is reversely conveyed 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 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. Thereafter, the recording medium 2 to which the toner image has been transferred is conveyed to the fixing unit 5 by the conveyance 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. Then, the recording medium 2 is discharged to a pair of discharge rollers 3g and 3g.
h, 3i, and through the reversing path 3j, the discharge tray 6
Discharge to The discharge tray 6 is provided on the upper surface of the apparatus main body 14 of the image forming apparatus A. In this embodiment, the swingable flapper 3k is operated, and the recording medium 2 can be discharged by the discharge roller pair 3m without passing through the reversing path 3j. In this embodiment, the pickup roller 3b, the transport roller pair 3c, 3d, registration roller pair 3e, conveyance guide 3f, discharge roller pair 3g, 3h, 3i
The conveying means 3 is constituted by the pair of discharge rollers 3m.

On the other hand, as shown in FIGS. 4 and 5, the process cartridge B rotates the photosensitive drum 7 and uniformly charges the surface thereof by applying a voltage to a charging roller 8 serving as a charging unit. Next, the photosensitive drum 7 is irradiated with laser beam light corresponding to the image information from the optical hand throw 1 through the exposure opening 1e to form a latent image. Then, the latent image is developed by a developer hand 9 using toner. 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 to rotate by the photosensitive drum 7. The developing means 9
Supplies toner to a developing area of the photosensitive drum 7 to develop a latent image formed on the photosensitive drum 7. As shown in FIG. 2, the optical means 1 has a laser diode 1a, a polygon mirror 1b, a lens 1c, and a reflection mirror 1d.

Here, the developing means 9 includes the toner container 1
The toner in 1A is rotated by rotation of the toner feeding member 9b.
It is sent to the developing sleeve 9c. Then, the developing sleeve 9c having the fixed magnet built therein is rotated, and a toner layer provided with a triboelectric charge by the developing blade 9d is formed on the surface of the developing sleeve 9c, and the toner is supplied to the developing area of the photosensitive drum 7. 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. Here, the developing blade 9d
Defines the amount of toner on the peripheral surface of the developing sleeve 9c and imparts a triboelectric charge. A toner agitating member 9b for circulating toner in the developing chamber is rotatably mounted near the developing sleeve 9c.

Then, as shown in FIG.
After applying a voltage having a polarity opposite to that of the toner image to transfer the toner image formed on the photosensitive drum 7 to the recording medium 2,
The residual toner on the photosensitive drum 7 is removed by the cleaning unit 10. Here, the cleaning hand thrower 10 scrapes off the toner remaining on the photosensitive drum 7 by an elastic cleaning blade 10a provided in contact with the photosensitive drum 7 and collects the toner in the waste toner reservoir 10b.

(Frame Configuration of Process Cartridge) As shown in FIG. 4, the process cartridge B according to the present embodiment has a toner container (toner storage section) for storing toner.
11A and a developing frame 12 having a developing means such as a developing sleeve 9c.
01b, a developing unit D as a second frame unit, a photosensitive drum 7, a cleaning blade 10
a and a cleaning unit C as a first frame unit having the charging roller 8 is rotatably connected with the shaft 20 as a fulcrum.

On the other hand, between the cleaning unit C and the developing unit D, a coil spring 22 as an urging means is provided.
a is present and in the assembled state it is biased in the compression direction. As a result, when the cleaning unit C is fixed, the developing unit receives a clockwise rotation force around the fulcrum shaft 20 in the drawing, and the developing sleeve unit E is pressed against the photosensitive drum 7.

(Developing Structure) In the process cartridge according to the present embodiment, jumping development using a magnetic one-component developer is used as the developing means. In the jumping development process, the clearance between the surface of the photosensitive drum 7 and the surface of the developing sleeve 9c is maintained at, for example, 0.30 ± 0.05 mm in order to obtain stable development against disturbances such as temperature, humidity, and drum charging state. There is a need to.

In the process cartridge described above, according to the present invention, in order to maintain the clearance between the drum surface and the developing sleeve surface with high accuracy, the first and second gap forming members as shown in FIG. , The second clearance forming members 103a, 103b, 106a, 106b
Is used.

The first clearance forming members 103a, 103
Reference numeral 3b denotes a resin ring which is coaxial with the photosensitive drum 7 and is provided at both ends thereof, and is press-fitted and fixed to the drum flanges 102a and 102b. Here, regarding the drum unit, (1) the flange 10 is attached to the drum cylinder 101.
2a, 102b are press-fitted, (2) the outer diameter of the drum cylinder 101 is finished (cut) by both center holes (not shown) of the flange, and (3) the clearance forming members 103a, 103
3b is press-fitted into the flange, and (4) the result of using the processing / assembly steps (1) to (4) of finishing (cutting) the outer diameter of the first clearance forming members 103a and 103b on the basis of both centers of the flange. , First clearance forming member 103
The cylindricity of the cylinder surface based on the outer diameters of a and 103b can be maintained within 0.03 mm.

The second clearance forming members 106a, 106
Reference numeral 6b denotes a metal ring which is coaxial with the developing sleeve 9c and is provided at both ends thereof. The metal ring is press-fitted and fixed to the sleeve flanges 105a, 105b. 103b.

The outer diameter dCD of the first clearance forming members 103a and 103b on the drum side and the outer diameter dC of the second clearance forming members 106a and 106b on the sleeve side.
Is determined to satisfy the following equation.

ΩD × dCD = ωS × dCS (1) dCD + dCS = dDRUM + dsLV + 2C (2) where ωD: angular velocity of the photosensitive drum ωS; angular velocity of the developing sleeve dCD; outer diameter of the first gap member dCS: outer diameter of the second gap member dDRUM: outer diameter of the photosensitive drum dSLV: outer diameter of the developing sleeve C: clearance between the photosensitive drum and the developing sleeve

In the process cartridge of this embodiment, since the developing sleeve is driven to rotate by the drum shaft via the pair of gears 110 and 111, the rotational speed ratio ωS / ωD = ZD / ZS (3) Here, ZD; number of teeth of drum gear 110 ZS; sleeve gear 1
The number of teeth is 11.

From the above equation (3), ωS / ωD = ZD / Z
S = 60/27 where dDRUM = 30 (mm), dSL
Assuming that V = 16 (mm) and C = 0.3 (mm), dCD = 32.138 (mm) dCS = 14.462 (mm) from the above equations (1) and (2). .

When test printing was performed using the process cartridge having the above configuration, it was found that the first and second gap forming members constituted by a pair of the drum side and the sleeve side were each fixed to each shaft. Nevertheless, a good image was output. Further, in the print durability test, almost no wear of the gap forming member was observed. As described above, the factors of the obtained good results are as follows: first, the relative slip does not occur at the contact portion of the pair of gap forming members;
In addition, there is a feature of the present configuration in which an assembling / machining process can be applied to high precision using machining after the assembly of the clearance forming member A.

As described above, in FIG. 1, when the ring-shaped clearance forming members 103a and 103b are pressed into the drum flanges 102a and 102b, the outer diameter of the drum cylinder 101 and the outer diameter of the clearance forming member are pressed after the pressing. Since simultaneous processing is possible, the clearance can be maintained with high precision.

The first clearance forming member 10
3a and 103b are the drum cylinders 101 of the photosensitive drum 7
It is preferable to form an integral structure with the drum flanges 102a and 102b provided at both ends of the drum.

For example, the first clearance forming member 10
By forming the parts 3a and 103b as a part of the drum flanges 102a and b, in addition to facilitating the assembly, the outer diameter of the drum cylinder 101 and the first clearance forming member 103 are formed.
Since the outer diameter portions a and 103b can be processed simultaneously, the clearance can be maintained with high accuracy.

The second clearance forming member 106
a and 106b are press-fitted into the developing sleeve flanges 105a and 105b, the outer diameter of the sleeve cylinder 104 and the outer diameter of the second clearance forming members 106a and 106b can be simultaneously processed after the press-fitting. And the developing sleeve 9c can be maintained with high precision.

The second clearance forming members 106a and 106b provided coaxially with the developing sleeve 9c are connected to the sleeve flanges 1 provided at both ends of the developing sleeve 9c.
It is preferable to have an integral structure with 05a, b.

That is, the second clearance forming member 10
If the 6a and 106b are formed as a part of the sleeve flanges 105a and 105b, the outer diameter of the sleeve cylinder 104 and the second clearance forming member 10 can be improved in addition to facilitating assembly.
Since the outer diameter portions 6a and 106b can be simultaneously processed, the clearance can be maintained with high accuracy.

The clearance forming members 103a and 103b provided coaxially with the photosensitive drum 7 may be rotatable with respect to the photosensitive drum 7.

For example, in FIG. 1, it is assumed that the ring-shaped first clearance forming members 103a and 103b are rotatably fitted to the drum flanges 102a and 102b. In this way, when the rotation speed of the photosensitive drum 7 and the rotation speed of the developing sleeve 9c fluctuate, the relative speed is changed to the first clearance forming member 103 on the ring.
The first clearance forming members 103a and 103b can be absorbed by the rotation of the drum flanges 102a and 103b with respect to the drum flanges 102a and 102b.
Wear of the outer diameter portion can be prevented.

The second clearance forming members 106a and 106b provided coaxially with the developing sleeve 9c may be rotatable with respect to the developing sleeve 9c.

That is, in FIG. 1, it is assumed that the ring-shaped second clearance forming members 106a and 106b are rotatably fitted to the developing sleeve flanges 105a and 105b. Even in this case, when the rotation speed of the photosensitive drum 7 and the rotation speed of the developing sleeve 9c fluctuate, this relative speed is used as the ring-shaped sleeve flange 105a,
b, the second clearance forming member 106 can be absorbed by the relative speed.
a, 106b can be prevented from being worn.

[0058]

As described above, according to the first aspect of the present invention, the first frame unit having the photosensitive drum and the developing sleeve are rotatable with respect to the first frame unit. A second frame unit supported, gap forming means for forming a predetermined gap between the photosensitive drum and the developing sleeve, and a pressing means for pressing the photosensitive drum and the developing sleeve together via the gap forming means. And a biasing means for biasing the developing sleeve, wherein the gap forming means is coaxial with the photosensitive drum and a first gap forming member provided at both ends thereof, and coaxial with the developing sleeve. And second gap forming members provided at both ends thereof, wherein the first gap forming member and the second gap forming member are in contact with each other at their outer diameter portions, and the first and second gap types are in contact with each other. By setting the outer diameters of these gap forming members so as to roll without slipping while eliminating the relative speed at the contact points of the members, wear, deformation, and destruction of the first and second gap forming members due to sliding friction are provided. , And high-quality images can be stably output over the durable life of the process cartridge.

According to the second aspect of the present invention, the first gap forming member provided coaxially with the photosensitive drum is made unrotatable with respect to the photosensitive drum, so that the outer diameter portion of the photosensitive drum and the first gap are prevented from rotating. The outer diameter portion of the forming member can be simultaneously processed, and the clearance between the photosensitive drum and the developing sleeve can be maintained with high accuracy.

According to the third aspect of the present invention, since the first gap forming member provided coaxially with the photosensitive drum is rotatable with respect to the photosensitive drum, the rotation speed of the photosensitive drum and the rotation of the developing sleeve are controlled. When the speed fluctuates, the relative speed can be absorbed by the rotation of the first gap forming member with respect to the photosensitive drum, so that wear of the first and second clearance forming members due to the generation of the relative speed can be prevented. .

According to the fourth aspect of the present invention, since the second gap forming member provided coaxially with the developing sleeve is not rotatable with respect to the developing sleeve, the outer diameter of the developing sleeve and the second gap forming are formed. Since the outer diameter of the member can be processed simultaneously, the clearance between the outer diameter of the photosensitive drum and the developing cleave can be maintained with high accuracy.

According to the fifth aspect of the present invention, the second gap forming member provided coaxially with the developing sleeve is rotatable with respect to the developing sleeve. When the speed fluctuates, the relative speed can be absorbed by the rotation of the second gap forming member with respect to the developing sleeve, so that the wear of the second gap forming member due to the generation of the relative speed can be prevented.

According to the sixth aspect of the present invention, the first gap forming member provided coaxially with the photosensitive drum is integrally formed with the drum flanges provided at both ends of the photosensitive drum cylinder. When the forming member has an integral structure with the photosensitive drum, in addition to facilitating the assembly, it is possible to simultaneously process the outer diameter portion of the photosensitive drum and the outer diameter portion of the first gap forming member. Can be maintained with high precision.

According to the seventh aspect of the invention, the second gap forming member provided coaxially with the developing sleeve is integrally formed with the sleeve flanges provided at both ends of the developing sleeve. Is integral with the developing sleeve, in addition to facilitating the assembly, the outer diameter of the developing sleeve and the outer diameter of the second gap forming member can be simultaneously processed, so that the clearance between the photosensitive drum and the developing sleeve can be improved. Can be maintained with high accuracy.

According to the present invention, since the process cartridge is detachably attached to the main body of the image forming apparatus, a high-quality image can be stably provided over the lifetime of the process cartridge. It is now possible to output.

[Brief description of the drawings]

FIG. 1 is a view showing a configuration of a developing process part of a process cartridge according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating an example of an image forming apparatus to which the process cartridge of FIG. 1 is applied.

FIG. 3 is an external perspective view of the image forming apparatus of FIG. 2;

FIG. 4 is a cross-sectional view of a process cartridge to which the developing process site structure of FIG. 1 is applied.

FIG. 5 is an external perspective view of the process cartridge of FIG.

FIG. 6 is a sectional view of a conventional process cartridge.

FIG. 7 is a view showing a configuration of a developing process portion of a conventional process cartridge.

[Explanation of symbols]

A image forming apparatus main body B process cartridge C cleaning unit (first frame unit) D developing unit (second frame unit) E developing sleeve unit 7 photosensitive drum 9c developing sleeve 101 photosensitive drum cylinder 104 sleeve cylinder 102a, 102b drum flange 105a, 105b Sleeve flange 103a, 103b First clearance forming member (first
Gap forming member) 106a, 106b Second clearance forming member (second
Gap forming member)

Claims (8)

[Claims] A first frame unit having a photosensitive drum; a second frame unit having a developing sleeve rotatably supported with respect to the first frame unit; A process cartridge comprising: a gap forming unit for forming a predetermined gap therebetween; and an urging unit for urging the photosensitive drum and the developing sleeve so as to press each other through the gap forming unit. The gap forming means includes a first gap forming member coaxial with the photosensitive drum and provided at both ends thereof, and a second gap forming member coaxial with the developing sleeve and provided at both ends thereof, When the first gap forming member and the second gap forming member are in contact with each other at their outer diameters, when the angular velocity of the photosensitive drum is given by ωD and the angular velocity of the developing sleeve is given by ωS Outer diameter dCS outer diameter dCD a second spacing member of the first gap member, satisfy the relationship .omega.D × dCD = .omega.S × dCS, and, DDRU the outer diameter of the photosensitive drum
M, wherein the outer diameter of the developing sleeve is given by dSLV, and the gap is given by C, wherein dCD + dCS = dDRUM + dSLV + 2C. 2. The process cartridge according to claim 1, wherein the first gap forming member provided coaxially with the photosensitive drum is not rotatable with respect to the photosensitive drum. 3. The process cartridge according to claim 1, wherein the first gap forming member provided coaxially with the photosensitive drum is rotatable with respect to the photosensitive drum. 4. The process cartridge according to claim 1, wherein the second gap forming member provided coaxially with the developing sleeve is not rotatable with respect to the developing sleeve. 5. The process cartridge according to claim 1, wherein a second gap forming member provided coaxially with the developing sleeve is rotatable with respect to the developing sleeve. 6. The process cartridge according to claim 2, wherein the first gap forming member provided coaxially with the photosensitive drum is integrally formed with drum flanges provided at both ends of the photosensitive drum cylinder. 7. The process cartridge according to claim 4, wherein the second gap forming member provided coaxially with the developing sleeve is integrally formed with sleeve flanges provided at both ends of the developing sleeve. 8. An image forming apparatus, wherein the process cartridge according to claim 1 is detachably attached to an image forming apparatus main body.