JPH07225532A - Grounding structure of phortosensitive drum - Google Patents

Abstract

PURPOSE:To obtain a grounding structure which assures stable grounding with a simple structure by bringing a conductive metallic member into contact with the front end of the central shaft of a photosensitive drum and forming a recessed part into which the front end of the central shaft of the photosensitive drum can be housed at this metallic member. CONSTITUTION:Conductive flanges 3, 4 are fixed to the right and left openings of a cylindrical supporting body 1 so as to be electrically conducted to this cylindrical supporting body 1, by which the photosensitive drum 2 is formed. The elastic conductive metallic member 2 is so arranged as to come into contact with the head part of a lead member 21. This metallic member 20 consists of a plate shape electrically coupled to the grounding part of the device body. The recessed part 22 of nearly a complementary shape to permit housing of the head part is formed in the part which comes into contact with the hemispherical head part of the lead member 21. This recessed part 22 is formed by drawing the metallic member 20 to a circular spherical surface shape. The contact of the central shaft or the photosensitive drum 2 and the metallic member 20 is made into surface-to-surface contact or line contact and the electrical conduction between both members is stabilized by formation of such recessed part 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grounding structure for obtaining electrical continuity between a cylindrical support and an apparatus main body in a photosensitive drum having a photosensitive body on the surface of a conductive cylindrical support.

[0002]

2. Description of the Related Art Various grounding structures have been proposed in order to obtain electrical continuity between a photosensitive drum and an apparatus main body. For example,
In Japanese Utility Model Laid-Open No. 62-51372, the shaft end of the photoconductor drum is covered with a conductive cap-shaped bush, and an elastic conductive metal member is brought into contact with the end surface of the bush to form a photosensitive drum. It is grounded. The grounding structure using the shaft end is schematically shown in FIG.
The elastic metal member 104 is brought into contact with the tip 103 of the conical end portion 2 of the contact member 2.

[0003]

In such a configuration, as shown in the figure, the contact between the central shaft 102 and the metal member 104 is point contact, which is unstable, and sometimes causes troubles such as grounding failure. It may have caused. For this reason, a structure has been proposed in which grounding is performed via a bearing that supports the central shaft 102 in the axial direction, but there is another problem that the structure is complicated.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a grounding structure capable of stably grounding with a simple structure.

[0005]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention brings an elastic conductive metal member for electrically conducting the photosensitive drum and the apparatus main body into contact with the tip of the central axis of the photosensitive drum. And a concave portion capable of accommodating the tip of the central axis of the photosensitive drum is formed in the metal member. Such a recess can be formed by drawing or by cutting and raising.

[0006]

With the formation of such a recess, the contact between the central axis of the photosensitive drum and the metal member becomes a surface contact or a line contact,
Electrical conduction between both members is stabilized.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. In the figure, reference numeral 1 is a cylindrical support made of a conductive material such as aluminum, and a photoconductor 2 is provided on its peripheral surface by coating, vapor deposition or coating. As is well known, the photoconductor 2 forms a toner image on its surface through the processes of charging, exposing and developing. Due to these processes, the cylindrical support 1 which is electrically connected to the electrodes of the photoconductor is grounded.

Conductive flanges 3 and 4 are fixed to the left and right openings of the cylindrical support 1 so as to be electrically connected to the cylindrical support 1, thus forming a photosensitive drum. Each of the flanges 3 and 4 is provided with concentric shaft portions 31 and 41 that form the rotation center axis of the photosensitive drum. In the illustrated example, one shaft portion 31 is a cylindrical shaft integrally formed with the flange 3, and the other shaft portion 41 is fixed so as to be fitted into the central portion of the flange 4. These shaft portions 31 and 41 are rotatably supported by support plates 8 and 9 of the apparatus main body by bearings 6 and 7, respectively, and are appropriately connected via a gear 11 fixed to the tip of the shaft 41 of the flange 4. Drive is obtained from the drive source, which rotates the photosensitive drum.

A lead member 21 having a hemispherical head portion is press-fitted or screwed toward the outer end of the shaft portion 31 of the flange 3 so as to be electrically connected to the flange 3. An elastic conductive metal member 20 is arranged so as to come into contact with the head portion 21a of the lead member 21. Metal member 20
Has a plate shape electrically connected to the ground portion of the apparatus main body, and a portion of the lead member 21 that contacts the hemispherical head portion 21a is substantially complementary to the head portion 21a capable of accommodating the head portion 21a. A concave portion 22 having a substantially spherical surface shape or a diameter larger than that of the head portion 21a is formed.

As shown in FIG. 2, the concave portion 22 is formed by narrowing the metal member 20 into a spherical surface shape, or in a portion which comes into contact with the head portion 21a of the lead member 21 in a radial shape as shown in FIG. Make multiple incisions and cut these 2
It is formed by cutting and raising 2a outward (to the left in FIG. 1). The concave portion 22 has a shape sufficient to make at least a surface or line contact with the head portion 21a of the lead member 21, and rotates the photosensitive drum, that is, the lead member 2.
It is preferable to select or process a material that does not cause abnormal noise due to contact friction with the concave portion 22 even by the rotation of 1.

[0011]

As described above, according to the present invention, a concave portion is formed in the contact portion of the metal member, and the tip of the shaft portion of the photosensitive drum is brought into surface or line contact with the concave portion, so that stable grounding can always be obtained.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an example of a grounding structure of a photosensitive drum according to the present invention.

FIG. 2 is an enlarged view showing a contact portion shown in FIG.

FIG. 3 is a schematic view showing an example of a conventional grounding structure.

FIG. 4 is a diagram showing another embodiment of the grounding structure according to the present invention.

[Explanation of symbols]

 1 Cylindrical support 2 Photoreceptor 3 Flange 4 Flange 20 Conductive metal member 21 Lead member 22 Recessed portion 31 Shaft portion 41 Shaft portion

Claims (2)

[Claims] 1. An elastic conductive metal member for electrically conducting the photosensitive drum and the apparatus main body is provided in contact with the tip of the center axis of the photosensitive drum, and the tip of the center axis of the photosensitive drum is attached to the metal member. A grounding structure for a photosensitive drum, characterized in that a recess that can be accommodated is formed. 2. The ground structure for a photosensitive drum according to claim 1, wherein the recess is formed by drawing or cutting and raising.