JPH11184308A - Insertion member into electrophotographic photoreceptor and electrophotographic photoreceptor using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a columnar member at a low cost, to decrease electrification noise and further to reduce the disassembly cost by make an electrophotographic photoreceptor have a structure to hold the columnar member through an elastic body. SOLUTION: The columnar member 2 worked to fit to the electrophotographic photoreceptor 1 is inserted in the photoreceptor 1. Then, the elastic body 3 is attached to the member 2, and the member 2 is held in the photoreceptor 1 through the elastic body 3. It is conceivable to form a groove 4 on the member 2 so as to fix the elastic body 3. The groove 4 prevents the elastic body 3 from being deviated when the member 2 is inserted in or taken out from the photoreceptor 1. It is desirable that the elastic body 3 is an O-ring and the member 2 is formed of plastic material whose specific gravity is >=1.5. Especially, it is desirable that the member 2 is made of polybutylene terephthalate resin incorporating >=20% glass fiber.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a member to be inserted into an electrophotographic photosensitive member and an electrophotographic photosensitive member used in an image forming apparatus having a contact charging device, and more particularly to an electrophotographic photosensitive member for reducing charging noise. And an electrophotographic photosensitive member into which the insertion member is inserted.

[0002]

2. Description of the Related Art In recent years, a charging device used in an image forming apparatus is an electrophotographic method in which a conductive member such as a roller type or a blade type is used instead of a corona discharge system represented by a scotron type or a contron type. 2. Description of the Related Art A contact charging device has been employed which applies pressure to a photoconductor to apply a predetermined potential to the electrophotographic photoconductor.

[0003] According to this method, the power supply device can be reduced in pressure, so that it can be downsized, and has the advantages of very little ozone generation.

However, if the number of rotations of the electrophotographic photosensitive member is increased to increase the speed of image formation, it is necessary to increase the frequency of the applied voltage in order to maintain a predetermined voltage. When this frequency exceeds a certain value, due to the Coulomb force generated between the charging roller and the electrophotographic photosensitive member due to the electric charge, and the restoring force due to the recovery of the elastic deformation of the charging roller,
Vibration of the electrophotographic photosensitive member is generated at twice the frequency of the normally applied voltage, and the vibrating sound causes noise to the surroundings. Further, the vibration induces image deterioration.

In order to suppress such vibration, conventionally,
Various measures have been taken, but in principle, a rigid or elastic body (solid or liquid with a certain mass), etc., is contacted, fixed or held in whole or in part inside the electrophotographic photosensitive member. The problem can be solved by increasing the mass and rigidity of the electrophotographic photosensitive member so that the natural frequency of the vibration system can be changed.

For this reason, generally, a method has been adopted in which a desired processing is performed on an aluminum ingot, which is inserted into an electrophotographic photosensitive member, and fixed with an adhesive. However, considering the materials and processing steps, the product cost is inevitably high, and in order to meet the recent demand for resource recycling, even when disassembling and reusing members, they are fixed with an adhesive. It is difficult to remove the aluminum ingot member from the electrophotographic photoreceptor, and even if it is removed, it takes time and effort to remove the adhesive on the surface of the member.

Various other members have been studied. For example, Japanese Patent Application Laid-Open No. HEI 5-142921 discloses that a cylinder made of urethane rubber is provided in a photosensitive drum. Stuff that comes into contact,
(2) JP-A-5-142922 discloses a photosensitive drum in which a coil spring is closely attached and fixed.
Japanese Patent Application Laid-Open No. 142923/142 discloses a method in which an insert made of a rigid or elastic body is inserted into a photosensitive drum and the insert is fixed by screw connection or groove connection.
Japanese Patent No. 8840 discloses a device including a member also serving as a rotating shaft, and the like. However, even in these prior arts, considering the selection, processing, and disassembly of the member, the product cost or the disassembly cost is reduced. There was a drawback that it would take.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide an insertion member for reducing charging noise and a charging noise in an electrophotographic photosensitive member used in an image forming apparatus having a contact charging device. An inexpensive electrophotographic photoreceptor is provided.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, by adopting a structure in which a columnar member is held in an electrophotographic photosensitive member via an elastic body. It has been found that the member can be manufactured at low cost, the charging noise can be reduced, and the disassembly cost can be reduced.

That is, the present invention is characterized in that in the insertion member for the electrophotographic photosensitive member, the insertion member is a member composed of at least two or more elastic members and a columnar member, and the elastic member is an O-ring. And the columnar member has a specific gravity of 1.5
The above-mentioned plastic material is preferable, and in particular, the columnar member is preferably made of polybutylene terephthalate resin containing 20% or more of glass fiber.

Further, an electrophotographic photosensitive member having the above-mentioned insertion member inserted therein is preferable.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of the structure of the electrophotographic photosensitive member of the present invention. The electrophotographic photoreceptor 1 has a columnar member 2 that is processed to fit the electrophotographic photoreceptor 1 inserted therein, and the columnar member 2 has an elastic body 3 attached thereto. The columnar member 2 is held by the electrophotographic photosensitive member 1 through the support 3.

The electrophotographic photosensitive member 1 has various dimensions depending on the type of the image forming apparatus to be used. However, the mass of the insertion member that can suppress charging noise varies depending on the shape of the electrophotographic photosensitive member 1. The shape of the columnar member 2 may be appropriately selected so as to be suitable for the electrophotographic photosensitive member 1.

The cylindrical member 2 is used to fix the elastic body 3.
The groove 4 may be provided. Provision of the groove 4 is effective in preventing the elastic body 3 from shifting when the cylindrical member 2 is inserted into or taken out of the electrophotographic photosensitive member 1.

In the case where a rotating shaft for rotating the electrophotographic photosensitive member 1 is inserted, the cylindrical member 2 may be provided with a through hole 5 in which the rotating shaft can be inserted.

Further, there is a space 6 surrounded by the electrophotographic photosensitive member 1, the columnar member 2, and the elastic member 3. In order to prevent the influence of the thermal expansion of the gas confined in the space 6, It is also effective to provide a through hole 7 that further penetrates the through hole 5.

As the material of the columnar member 2, any material can be used as long as it increases the mass and rigidity of the electrophotographic photoreceptor 1. However, the material is inexpensive and easy to process. Therefore, a plastic material having a specific gravity of 1.5 or more is preferable.

Among them, a polybutylene terephthalate resin containing 20% or more of glass fiber is most preferable from the viewpoint of easy availability, price, specific gravity, ease of processing, and the like.

The elastic member 3 may be of any type as long as it can hold the columnar member 2 on the electrophotographic photosensitive member 1, but an O-ring is most preferable in terms of availability, cost and the like.

One or more elastic members 3 may be provided to hold the columnar member 2 on the electrophotographic photosensitive member 1, but two or more elastic members are provided to stably fix the columnar member 2. It is effective.

[0021]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited to these Examples.

(Embodiment) As shown in FIG.
A columnar member made of polybutylene terephthalate resin containing 30% of glass fiber having a length of 0 mm and a length of 133 mm (specific gravity: 1.
6) At a distance of 10 mm from both ends, a depth of 1.9
The grooves 4 of mm were provided by cutting.

The cylindrical member 2 was provided with a through hole 5 for a rotating shaft having a diameter of 8 mm, and a central hole of the cylindrical member 2 was provided with a through hole 7 having a diameter of 2 mm passing through the through hole.

The columnar member obtained in this manner is subjected to JIS
An O-ring 3 having a thickness of 2.4 mm and an inner diameter of 21.8 mm according to JIS call number P22 and a material code A shown in B 2401 was mounted to prepare an insertion member. The weight of the insertion member was measured to be about 120 g.

This insertion member is formed to have a thickness of 1.5 mm and an inner diameter of 2 mm.
The electrophotographic photoreceptor was obtained by inserting it into an electrophotographic photoreceptor 1 of 8.5 mm and a length of 254.0 mm made of aluminum so as to be substantially symmetrical.

When the thus obtained electrophotographic photosensitive member was mounted on an actual machine and tested for charging noise, the charging noise was clearly reduced as compared with the electrophotographic photosensitive member without the insertion member inserted.

Further, in order to confirm the holding state of the insertion member, the insertion member was vertically dropped on the floor from a height of 1 m. However, no movement of the insertion member was observed, and the holding state was good.

In removing the insertion member, it was possible to remove the insertion member very easily and in a short time by using a rod-shaped member and pushing it out by hand from one side of the electrophotographic photosensitive member.

In the case of the electrophotographic photosensitive member according to the present embodiment, the dimensions, shape, weight and the like of the insertion member are preferably as described above from the viewpoint of preventing charging noise and material cost.

[0030]

According to the present invention, it is possible to provide an inexpensive member for insertion into an electrophotographic photoreceptor for reducing charging noise and an electrophotographic photoreceptor for reducing charging noise. Further, the insertion member can be easily taken out. Since it is available and can be reused, the disassembly cost can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 electrophotographic photosensitive member 2 columnar member 3 elastic member 4 groove 5 through hole 6 space 7 through hole 5 penetrating through hole 5

Claims (4)

[Claims] 1. An insertion member for an electrophotographic photosensitive member,
The insertion member for an electrophotographic photosensitive member, wherein the insertion member is a member including at least two or more elastic bodies and a columnar member. 2. The insertion member according to claim 1, wherein the elastic member is an O-ring, and the cylindrical member is a plastic material having a specific gravity of 1.5 or more. 3. The insertion member according to claim 1, wherein the columnar member is made of a polybutylene terephthalate resin containing 20% or more of glass fiber. 4. An electrophotographic photosensitive member having the insertion member according to claim 1, 2 or 3 inserted therein.