JPH08123251A - Rotating member, processing cartridge and image forming device - Google Patents

Abstract

PURPOSE: To provide a rotating member, a processing cartridge and an image forming device capable of preventing the degradation of the roundness of the rotating member of an image carrier or the like and forming the image having high quality. CONSTITUTION: In the rotating member in which an engaging member is force- fitted into at least one end of a cylindrical member, the engaging member is provided with an engaging part 8c2 having outside diameter slightly larger than the inside diameter of the cylindrical member and to be force-fitted into the inside diameter of the cylindrical member, a shaft part 8c5 positioned at the center of the rotation of the cylindrical member, ribs 8c6 supporting the engaging part 8c2 in a radial direction against the shaft part 8c5, and small diameter parts on the outer peripheral surface of the engaging part 8c2 and at the position where the ribs 8c6 are connected to the inner peripheral surface. Also, the processing cartridge and the image forming device are constituted by using the rotating member as the image carrier or a developing roller.

Description

Detailed Description of the Invention

The present invention relates to a rotary member having a high circularity, a process cartridge using the rotary member, and an image forming apparatus to which the process cartridge can be mounted.

[0002]

2. Description of the Related Art In an electrophotographic image forming apparatus, a latent image is formed by selectively exposing a latent image on an image carrier uniformly charged by a charger, and the latent image is developed by a developer by a developer. At the same time as visualizing, the image formed by the developer is transferred to a recording medium to record an image.

In such an apparatus, as shown in FIG. 2, flange members are attached to both ends of the cylindrical member of the image carrier 8 and the developing roller 10d, and a spindle is provided in a shaft hole provided in the flange member. The developing roller 10d is fitted and rotatably supported, and the developing roller 10d is rotatably faced with a minute interval of about 300 ± 30 μm, and the toner layer formed on the surface of the developing roller is formed on the image carrier. The image is transferred and developed according to the image.

If the gap between the image carrier 8 and the developing roller 10d is not maintained at an appropriate value, the toner transfer to the image carrier 8 will not be carried out accurately, and the toner image transferred to the recording medium will be shaded. Will appear. Therefore, the developing roller 10
Spacer rollers 10f are attached near both ends of d, and the thickness of the rollers 10f guarantees that the gap between them is constant.

There is also a method of attaching the flange members attached to both ends of the image carrier 8 by adhesion, caulking or the like. However, since no adhesive agent is required and the manufacturing is easy, the flange members are press-fitted. The mounting method is often used.

Therefore, the flange member has a shaft portion 50 having a shaft hole 50a and a cylindrical image carrier 8 as shown in FIG.
The engaging portion 51 having an outer diameter slightly larger than the inner diameter of
It is constituted by ribs 52 for supporting a radial load applied to the above, and the engaging portions 51 are press-fitted into both ends of the cylindrical member 8a by aluminum drawing or the like.

When the image forming apparatus is downsized, the ribs 52 are reduced in size of the cylindrical member 8a such as an image carrier and the flange, and the ribs 52 are often provided with only about four ribs 52.

[0008]

However, since the cylindrical member 8a press-fits the flange member, the cylindrical member 8a is elastically deformed to expand the diameter of the image carrier and generate the contracting force F, and the flange member resists the external force. Then, a drag force N is generated on the rib 52.

As a result, in the outer peripheral portion of the flange member with respect to the image bearing member 8, the portion without the rib 52 is easily deformed with respect to the portion with the rib 52, and the outer diameter of the cylindrical member 8a which abuts against the outer peripheral portion. Swells at the position of the rib 52 with respect to the perfect circle. The influence of this deformation becomes smaller from the longitudinal end of the cylindrical member 8a toward the central portion.

When the image carrier is deformed, the spacer roller 10f contacting the image carrier follows the deformation, and the developing roller 10d is cam-moved with respect to the rotation center of the image carrier 8. become. As a result, the gap between the image carrier 8 and the developing roller 10d is not constant, and unevenness of light and shade may occur in the image in the cycle of the cam movement.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object thereof is to prevent deterioration of the roundness of a rotating member such as an image bearing member and to enable high quality image formation. A member, a process cartridge, and an image forming apparatus are provided.

[0012]

A typical structure according to the present invention for achieving the above object is a rotary member in which an engaging member is press-fitted into at least one end of a cylindrical member, wherein the engaging member is An engaging portion having an outer diameter slightly larger than the inner diameter of the cylindrical member and press-fitted into the inner diameter of the cylindrical member, a shaft portion located at the center of rotation of the cylindrical member, and an engaging portion with respect to the shaft portion. And a small diameter portion at a position on the outer peripheral surface of the engaging portion where the rib and the inner peripheral surface are connected to each other.

Further, the present invention is characterized in that a process cartridge and an image forming apparatus are constructed by using the rotating member as an image carrier or a developing roller.

[0014]

In the above structure, when the engaging member is press-fitted into the end of the cylindrical member, the diameter of the cylindrical member swells and a contracting force is generated. Accordingly, the engaging member opposes the contracting force. When a drag force is generated, the drag force does not become particularly strong in the rib portion, and becomes uniform as a whole. As a result, the deformation of the cylindrical member is reduced, and deterioration of the roundness is prevented. Therefore, by configuring the image carrier and the developing roller as described above, it is possible to obtain a high-quality image without image shading.

[0015]

An embodiment according to the present invention will be described below with reference to the drawings.

[First Embodiment] First, regarding an image forming apparatus to which the process cartridge according to the first embodiment can be mounted,
A specific description will be given with reference to FIGS. 1 to 5. 1 is an explanatory view of an engaging member, FIG. 2 is an explanatory view of an image carrier and a developing roller, FIG. 3 is an explanatory view of a configuration of an image forming apparatus, FIG. 4 is an explanatory view of a configuration of a process cartridge, FIG. 5 is a diagram illustrating the mounting configuration of the process cartridge.

Here, as the order of description, the overall structure of the image forming apparatus in which the process cartridge is mounted will be described first, and then the structure of the image carrier will be described.

{Overall Configuration} This image forming apparatus A is shown in FIG.
As shown in FIG. 3, a light image based on image information is emitted from the optical system 1 to form a toner image on the photosensitive drum, which is an image carrier. In synchronism with the formation of the toner image, the recording medium 2 is conveyed from the cassette 3a by a conveying means 3 including a pickup roller 3b, a reversing roller 3c, and pinch rollers 3c1, 3c2, 3c3 which are pressed against this and rotate. Further, in the image forming section formed as a process cartridge B, the toner image formed on the photosensitive drum is transferred to the recording medium 2 by applying a voltage to the transfer roller 4 serving as a transfer unit, and the recording medium 2 is transferred. The transfer toner image is fixed to the recording medium 2 by being conveyed to the fixing means 5 which is composed of a fixing rotating body 5b having a heater 5a built therein and a driving roller 5c for pressing and conveying the recording medium 2 to the rotating body 5b. Then, the recording medium 2 is ejected onto the discharge roller pair 3d1, 3d2.
And the pair of discharge rollers 3e1 and 3e2, and the reverse conveyance path 6
It is configured to be discharged to the discharge portion 7 through the.

On the other hand, in the process cartridge B forming the image forming section, as shown in FIG. 4, the photosensitive drum 8 having a photosensitive layer is rotated, and its surface is applied with a voltage to a charging roller 9 as a charging means. Is uniformly charged, the optical image from the optical system 1 is exposed on the photosensitive drum 8 through the exposure section to form a latent image, and the latent image is developed by the developing means 10. The developing means 10 feeds the toner in the toner reservoir 10a by means of a toner feeding member 10b, and the fixed magnet 10
While rotating the developing roller 10d containing c, a toner layer to which a triboelectric charge is applied by the developing blade 10e is formed on the surface of the developing roller 10d, and the toner is transferred to the photosensitive drum 8 according to the latent image. As a result, a toner image is formed and visualized. Then, after a voltage having a polarity opposite to that of the toner image is applied to the transfer roller 4 to transfer the toner image to the recording medium 2, the cleaning blade 11a scrapes off the toner remaining on the photosensitive drum 8 and scoops it with the squeeze sheet 11b. Collecting and collecting waste toner
The cleaning means 11 collecting to the 11c is configured to remove the residual toner on the photosensitive drum 8. still,
The parts such as the photosensitive drum 8 are composed of a lower frame body 12 and an upper frame body 13.
The cartridge is supported by a housing which is combined with the above to form a cartridge, and is detachably attached to the cartridge attaching means provided in the apparatus main body 14.

The cartridge mounting means comprises an opening / closing member 14
When a is opened, as shown in FIG. 5, a cartridge mounting space is provided, and cartridge mounting guide portions 15 are provided on the left and right inner side surfaces of the apparatus main body 14. This left and right guide part 15
A first guide rail 15a and a second guide rail 15b for inserting the process cartridge B are provided opposite to each other. On the other hand, on both outer side surfaces of the process cartridge B, the process cartridge B projects outward from the rotation center position of the photosensitive drum 8 and
A cylindrical projection 15c having a radius substantially the same as that of the groove 15a1 provided at the end of the guide rail 15a is provided, and a guide projection 15d is provided continuously to the cylindrical projection 15c. Further, the engaging portion 15 is provided on the lower front side in the insertion direction of the process cartridge B.
e is provided.

When the process cartridge B is mounted, the cylindrical protrusion 15c and the guide ridge 15d of the process cartridge B are guided by the first guide rail 15a, and the engaging portion 15e is guided by the second guide rail 15b. In this state, the process cartridge B is inserted into the image forming apparatus A by inserting the process cartridge B and closing the opening / closing member 14a.

{Structure of Image Carrier} Next, the photosensitive drum 8 which is a rotating member will be described with reference to FIGS. This photosensitive drum 8 is formed by drawing aluminum or the like to form a cylindrical member 8a, and after applying a photosensitive layer to the surface of the cylindrical member 8a, a flange gear 8b is attached to one end as shown in FIG. A flange member 8c, which is an engaging member, is attached to the other end.

As a method of attaching the flange member 8c, there are adhesion, caulking, press fitting, etc., but in the present embodiment, it is not necessary to use an adhesive or the like, and since it is easy to install, the flange member 8c is mounted by press fitting. . Therefore, as shown in the front view of FIG. 1 (a), the flange member 8c has an insertion portion 8c1 having a diameter smaller than the inner diameter of the cylindrical member 8a, and slightly smaller than the inner diameter of the cylindrical member 8a (50 μm to 100 μm).
The engagement portion 8c2 having a large diameter and the flange portion 8c3 having a diameter larger than the engagement portion 8c2 are provided. A sectional view taken along the line D-D of (a) is shown in FIG. 1 (b). As can be seen from this, a shaft portion 8c5 having a shaft hole 8c4 in the radial center of the engagement portion 8c2.
Is provided, and four ribs 8c6 are provided so as to connect the shaft portion 8c5 and the engaging portion 8c2, and the engaging portion 8c2 is reinforced.

The engaging portion 8c2 of the flange member 8c is press-fitted and attached to the end portion of the cylindrical member 8a, and the shaft hole 8c4 is provided with a shaft.
16 (see FIG. 2) is inserted to rotatably support the photosensitive drum 8.

The flange member 8c is formed by injection molding a resin member such as POM.

The photosensitive drum 8 is, as shown in FIG.
Spacer roller 10 fitted near both ends of the developing roller 10d
abutting f, and a minute interval (300 ±
Face each other with a space of about 30 μm. For this purpose, the cylindrical member 8
When the circularity of a becomes low, the interval changes and the image quality deteriorates. Therefore, in this embodiment, as shown in FIG. 1B, the rib 8c6 is formed on the outer peripheral surface of the engaging portion 8c2.
The recess 8c7 is provided so that the position where the inner peripheral surface is connected to the inner peripheral surface is a smaller diameter portion than the other outer peripheral surfaces.

Thus, when the recess 8c7 is provided at the position of the rib 8c6, when the engaging portion 8c2 is press-fitted into the cylindrical member 8a, the diameter of the cylindrical member 8a swells and a contracting force is generated. As a result, a reaction force against the contraction force is generated in the engaging member 8c2, but this reaction force does not become particularly strong at the rib 8c6 portion, and becomes uniform as a whole. As a result, the cylindrical member 8
The deformation of a is reduced, and the deterioration of roundness is prevented. Therefore, the minute gap between the photosensitive drum 8 and the developing roller 10d does not change, and a high-quality image without image shading can be obtained.

Regarding the flange gear 8b attached to the other end of the cylindrical member 8a, in order to transmit the rotational force from the main body of the apparatus to the cylindrical member 8a, the method of attaching to the cylindrical member 8a is not press fitting, but bonding, caulking or the like. May be In this case, since the diameter of the cylindrical member 8a does not swell by attaching the flange gear 8b, the roundness of the cylindrical member 8a does not deteriorate even if it is not configured like the flange member 8c. However, in the case where the flange gear 8b is press-fitted and attached, the outer peripheral surface of the engaging portion is the same as the above-described flange member 8c, and the position where the rib is provided is smaller than the other outer peripheral surface. It is preferable to provide the depressions so that

Further, as shown in FIG. 2, the developing roller 10d
Also, the flange member 17 is attached to both ends of the cylindrical member, and is rotatably supported by the shaft 18 via the flange member 17. However, when the flange member 17 is press-fitted and attached, it is the same as the above-mentioned flange member 8c. It is preferable to have the constitution because the circularity of the developing roller can be prevented from being deteriorated.

[Second Embodiment] In the above-described first embodiment, the outer peripheral surface of the engaging portion 8c2 of the flange member 8c is
An example has been shown in which the recess 8c7 is provided so that the position where the rib 8c6 and the inner peripheral surface are connected is a smaller diameter portion than the other outer peripheral surfaces.
You may comprise as shown in FIG. In this configuration, instead of providing the recess 8c7 of the first embodiment, the rib 8c6 and the inner peripheral surface are provided by providing three protrusions 8c8 on the outer peripheral surface of the engaging portion 8c2 where the rib 8c6 does not exist. Are connected to each other at a smaller diameter portion than the other outer peripheral surface.

Even with this structure, the outer diameter of the engaging portion 8c2 at the rib position becomes small, and as a result, the cylindrical member 8 is formed.
The resisting force against the contracting force of a does not become particularly strong at the rib 8c6 portion and becomes uniform as a whole. Therefore, the roundness of the cylindrical member 8a is prevented from being deteriorated, and the same effect as that of the first embodiment can be obtained.

[Other Embodiments] In the first embodiment described above, 4
Although the example in which the ribs 8c6 are provided is shown, the number of ribs need not be limited to four, and the example in which the three protrusions 8c8 are provided between the ribs is shown in the second embodiment. The number of protrusions need not be limited to three.

Although the photosensitive drum 8 and the developing roller 10d are illustrated as the rotating member in the above-described embodiment, the present invention is not limited to the rotating member for attaching the flange member to the cylindrical member which needs to prevent the deterioration of the roundness. The invention can be preferably applied.

The process cartridge B described above is not limited to the case of forming a single color image as described above, but a plurality of developing means are provided to form a plurality of color images (for example, a two color image, a three color image or a full color image). The present invention can also be suitably applied to a cartridge.

As the developing method, various known developing methods such as a two-component magnetic brush developing method, a cascade developing method, a touchdown developing method and a cloud developing method can be used.

The image bearing member is not limited to the above-mentioned photosensitive drum, but includes, for example, the following. First, a photoconductor is used as the photoconductor, and as the photoconductor, for example, amorphous silicon, amorphous selenium,
Zinc oxide, titanium oxide, organic photoconductor (OPC) and the like are included. The shape on which the photoconductor is mounted includes, for example, a drum-shaped, belt-shaped rotating body, a sheet-shaped body, and the like. In general, 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 of an aluminum alloy or the like. It is.

As for the structure of the charging means, the so-called contact charging method was used in the above-described first embodiment, but a tungsten wire which has been conventionally used as another structure is provided with a metal shield such as aluminum around the three sides. It goes without saying that a configuration may be used in which positive or negative ions generated by applying a high voltage to the tungsten wire are moved to the surface of the photosensitive drum to uniformly charge the surface of the drum.

The charging means may be of a blade type (charging blade), a pad type, a block type, a rod type, a wire type or the like, other than the roller type.

Further, as a method for cleaning the toner remaining on the photosensitive drum, the cleaning means may be constituted by using a blade, a fur brush, a magnetic brush or the like.

The above-mentioned process cartridge is
For example, an electrophotographic photosensitive member as an image carrier and at least one process means are provided. Therefore, as the mode of the process cartridge, in addition to the embodiment described above, for example, the image carrier and the charging means are integrally made into a cartridge, which can be attached to and detached from the apparatus main body. The image carrier and the developing means are integrally formed into a cartridge, which can be attached to and detached from the main body of the apparatus. The image carrier and the cleaning means are integrally made into a cartridge so that it can be attached to and detached from the apparatus main body. Further, there is one in which an image carrier and two or more of the above-mentioned process means are combined into an integrated cartridge, which can be attached to and detached from the apparatus main body.

That is, the above-mentioned process cartridge is one in which the charging means, the developing means or the cleaning means and the electrophotographic photosensitive member are integrally formed into a cartridge, and the cartridge can be attached to and detached from the main body of the image forming apparatus. . Further, at least one of the charging means, the developing means, and the cleaning means and the electrophotographic photosensitive member are integrally made into a cartridge so that it can be attached to and detached from the main body of the image forming apparatus. Further, it means that at least the developing means and the electrophotographic photosensitive member are integrally made into a cartridge so as to be attachable to and detachable from the apparatus main body.

In the above-described embodiment, the photosensitive drum and the developing roller are formed into a cartridge, and the process cartridge is mounted to form an image. However, the photosensitive drum and the developing roller are not formed into a cartridge, The present invention can be similarly applied to an image forming apparatus directly attached to the apparatus main body.

Further, although the laser beam printer has been illustrated as the image forming apparatus in the above-mentioned embodiments, the present invention is not limited to this, and other image forming apparatuses such as an electrophotographic copying machine, a facsimile machine, a word processor and the like can be used. It is also possible to use for.

[0044]

As described above, according to the present invention, the small diameter portion is provided on the outer peripheral surface of the engaging portion press-fitted into the end portion of the cylindrical member, and at the position where the rib and the inner peripheral surface are connected. When the engaging member is press-fitted into the end of the cylindrical member, the diameter of the cylindrical member swells to generate a contracting force, and when the engaging member accordingly generates a resisting force against the contracting force, Does not become particularly strong at the rib portion and becomes uniform as a whole.
As a result, the deformation of the cylindrical member is reduced, and deterioration of the roundness is prevented. Therefore, by forming the image carrier and the developing roller as described above, it is possible to obtain a high-quality image without image shading.

The small diameter portion can be easily formed by providing the engaging member with a recess or a protrusion.

[Brief description of drawings]

FIG. 1A is a front explanatory view of an engagement member, and FIG. 1B is a DD arrow view of FIG.

FIG. 2 is an explanatory diagram of a photosensitive drum and a developing roller.

FIG. 3 is a diagram illustrating the configuration of an image forming apparatus.

FIG. 4 is a structural explanatory view of a process cartridge.

FIG. 5 is a diagram illustrating a mounting configuration of a process cartridge.

FIG. 6A is a front explanatory view of an engagement member according to another embodiment, and FIG. 6B is a view taken along the line EE of FIG.

FIG. 7 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Optical system 2 ... Recording medium 3 ... Conveying means 4 ... Transfer means 5 ... Fixing means 8 ... Photosensitive drum 8a ... Cylindrical member 8b ... Flange gear 8c ... Flange member 8c2 ... Engaging portion 8c6 ... Rib 8c7 ... Recess 8c8 ... Protrusion 10 ... Developing means 10d ... Developing roller 10f ... Spacer roller 11 ... Cleaning means

Claims (11)

[Claims] 1. A rotating member in which an engaging member is press-fitted into at least one end of a cylindrical member, wherein the engaging member has an outer diameter slightly larger than an inner diameter of the cylindrical member, and an inner diameter of the cylindrical member. An engaging portion that is press-fitted into the shaft, a shaft portion that is located at the center of rotation of the cylindrical member, and a rib that radially supports the engaging portion with respect to the shaft portion, and that is an outer peripheral surface of the engaging portion. A rotating member having a small diameter portion at a position where the rib and the inner peripheral surface are connected. 2. The rotating member according to claim 1, wherein the small-diameter portion has a recess formed on the outer periphery of the rib connecting position of the engaging portion. 3. The rotating member according to claim 1, wherein the small diameter portion is formed by providing a protrusion at a position other than the outer periphery of the rib connecting position of the engaging portion. 4. A process cartridge attachable to and detachable from a main body of an image forming apparatus, wherein a rotatable image carrier, at least one process unit acting on the image carrier, and the image carrier are at least one of a cylindrical member. A rotating member having an engaging member press-fitted into an end thereof, wherein the engaging member has an outer diameter slightly larger than the inner diameter of the cylindrical member, and an engaging portion press-fitted into the inner diameter of the cylindrical member; Has a shaft portion located at the center of rotation and a rib that radially supports the engaging portion with respect to the shaft portion, and is an outer peripheral surface of the engaging portion, wherein the rib and the inner peripheral surface are connected. A process cartridge having a small-diameter portion at a position to be formed. 5. A process cartridge attachable to and detachable from a main body of an image forming apparatus, comprising: an image bearing member; a developing unit having a developing roller acting on the image bearing member; and the developing roller associated with at least one end of a cylindrical member. A rotating member having a mating member press-fitted therein, wherein the engaging member has an outer diameter slightly larger than the inner diameter of the cylindrical member, and the engaging portion press-fitted into the inner diameter of the cylindrical member, and the rotation center of the cylindrical member. And a rib for supporting the engaging portion in the radial direction with respect to the shaft portion, the outer peripheral surface of the engaging portion,
A process cartridge having a small diameter portion at a position where the rib and the inner peripheral surface are connected. 6. The process cartridge comprises a charging means, a developing means or a cleaning means as the process means, and an electrophotographic photosensitive member as the image carrier, which are integrally formed into a cartridge, and the cartridge is formed into an image forming apparatus main body. The process cartridge according to claim 4, wherein the process cartridge is removable. 7. The image forming apparatus is a process cartridge in which at least one of a charging unit, a developing unit, and a cleaning unit as the process unit, and an electrophotographic photosensitive member as the image carrier are integrally formed into a cartridge. The process cartridge according to claim 4, which is removable from the main body. 8. The process cartridge is configured such that at least a developing unit as the process unit and an electrophotographic photosensitive member as the image carrier are integrally made into a cartridge so as to be attachable to and detachable from the main body of the image forming apparatus. The process cartridge according to claim 4, which is a product. 9. An image forming apparatus, wherein a process cartridge is attachable / detachable and forms an image on a recording medium, a mounting means for mounting the process cartridge according to claim 4 or 5, and an image carrier. An image forming apparatus comprising: a transfer unit for transferring the formed image to a recording medium; and a conveying unit for conveying the recording medium. 10. An image forming apparatus for forming an image on a recording medium, an image carrier, a developing unit having a developing roller for developing the image formed on the image carrier, and the developed image on the recording medium. A transfer unit for transferring the recording medium, and a transfer unit for transferring the recording medium, wherein the image carrier or the developing roller is a rotary member in which an engaging member is press-fitted into at least one end of a cylindrical member, The engaging member has an outer diameter slightly larger than the inner diameter of the cylindrical member, the engaging portion press-fitted into the inner diameter of the cylindrical member, a shaft portion located at the rotation center of the cylindrical member, and the shaft portion. A rib that supports the engaging portion in a radial direction with respect to the outer peripheral surface of the engaging portion, and has a small diameter portion at a position where the rib and the inner peripheral surface are connected to each other. Forming equipment. 11. The image forming apparatus according to claim 9, wherein the image forming apparatus is an electrophotographic copying machine, a laser beam printer, or a facsimile machine.