JPH05297782A - Photosensitive drum device - Google Patents

Abstract

PURPOSE:To provide a photosensitive drum device where a photosensitive drum is surely grounded. CONSTITUTION:This device is provided with a conductive grounding member 4 which is electrically connected to the inner peripheral surface of the photosensitive drum 1 and fitted and inserted in a photosensitive drum shaft 3 engaged with the photosensitive drum 1 through a flange 2. When a grounding brush 5 partitioned by plural grooves 6 radially formed in the center part of the member 4 is fitted and inserted in the shaft 3, it is bent and brought into contact with the shaft 3, so that charge on the photosensitive drum 1 is allowed to escape to the shaft 3 and the drum 1 is surely grounded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive drum device used in an electrophotographic printer or the like and having a new grounding structure.

[0002]

2. Description of the Related Art A photosensitive drum used in an electrophotographic printer or the like usually has a structure in which a plurality of photosensitive layers are provided on the outer peripheral surface of a cylindrical body made of a conductive material such as aluminum, and flanges are provided at both ends thereof. Is provided, and a drive shaft for rotating the photosensitive drum is provided at one end thereof. In the process of exposing an image on the photosensitive drum, after the outer peripheral surface of the photosensitive drum is charged, light is irradiated to expose the photosensitive layer and the potential on the photosensitive drum must be zero. The drum must be grounded by some means.

Conventionally, since the flanges at both ends of the photosensitive drum are made of metal, it is not necessary to take any special measures for grounding, and charges can be released from the drive shaft of the photosensitive drum through the flanges. there were.

On the other hand, in recent small electrophotographic printers and the like, a flange made of resin or the like having poor conductivity has come to be used in view of workability and cost, and it is used for grounding. New ideas are needed.

[0005]

As described above, when the flange provided on the photosensitive drum is made of resin having poor conductivity, there is a problem in that the photosensitive drum is not sufficiently grounded. Therefore, it is an object of the present invention to solve the above problems and provide a photosensitive drum device capable of reliably grounding the photosensitive drum.

[0006]

SUMMARY OF THE INVENTION According to the present invention, a grounding brush having a grounding brush electrically connected to an inner peripheral surface of a photosensitive drum and flexibly contacting a photosensitive drum shaft engaged with the photosensitive drum is provided. Provided is a photosensitive drum device, which is provided with a member.

Further, at least one of the ground brushes is fitted into a groove provided on the shaft of the photosensitive drum, and the ground member is provided through a photosensitive drum device and a holding member having conductivity. Is also electrically connected to the inner peripheral surface of the photosensitive drum.

[0008]

According to the present invention, the charges on the photosensitive drum are released to the photosensitive drum shaft through the grounding member, so that the photosensitive drum is surely grounded.

Further, since the ground brush of the ground member comes into contact with the photosensitive drum while flexing, the repulsive force pre-presses the photosensitive drum in the axial direction of the photosensitive drum and in the radial direction of the photosensitive drum, and the vibration caused by the rotation of the photosensitive drum is generated. Suppressed.

Further, when the photosensitive drum shaft is a drive shaft for rotating the photosensitive drum, the ground brush of the ground member is fitted into the groove portion provided on the photosensitive drum shaft so that the ground member is interposed. The rotational force of the photosensitive drum shaft is transmitted to the photosensitive drum.

[0011]

Embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing a first embodiment of the present invention. FIG. 1A is a sectional view showing a state in which a grounding member 4 is fitted and inserted into a photosensitive drum shaft 3 that is engaged with the photosensitive drum 1 via a flange 2, and FIG. FIG. 2 is a plan view of the cross section of the photosensitive drum 1 shown in FIG.

As shown in the figure, the grounding member 4 has a plurality of grounding brushes 5 at the center thereof, and the grounding member 4 is arranged so that the grounding brush 5 contacts the photosensitive drum shaft 3 while flexing. It is fitted on the shaft 3. Here, the ground brush 5 is
It is integrally formed with the ground member 4 by radially forming a plurality of grooves 6 from the center of the ground member 4 by pressing, etching, wire-cut electric discharge, or the like.
In the figure, eight ground brushes 5 are provided, but the number thereof is not limited to the case of this embodiment, and can be arbitrarily selected. A side wall 7 is formed on the outer periphery of the ground member 4 by pressing or deep drawing. The outer peripheral surface of the side wall 7 is pressed against the inner peripheral surface of the photosensitive drum 1, and the flange 2 is inserted from the inside. Is fixed by being press-fitted. Further, the ground member 4 is fixed to the end surface of the flange 2 by a fixing pin 8. The fixing pin 8 is for reinforcement and may be omitted if not particularly required.

As described above, the ground brush 5 of the ground member 4
Is in contact with the photosensitive drum shaft 3 while flexing, the repulsive force acts in the photosensitive drum shaft direction and the photosensitive drum radial direction. Due to this repulsive force, reliable electrical continuity can be maintained between the ground brush 5 and the photosensitive drum shaft 3, and between the ground member 4 and the photosensitive drum 1. As a result, the charge on the photosensitive drum 1 can be released to the photosensitive drum shaft 3 via the grounding member 4, and the photosensitive drum 1 can be reliably grounded. Further, due to this repulsive force, the photosensitive drum 1 is preloaded in the axial direction of the photosensitive drum and the radial direction of the photosensitive drum, so that the vibration accompanying the rotation of the photosensitive drum 1 can be suppressed.

In this embodiment, the photosensitive drum shaft 3 may be a drive shaft for rotating the photosensitive drum 1 or may be a fixed shaft that does not rotate. In the former case,
The photosensitive drum shaft 3 is connected to the flange 2, and the rotational force of the photosensitive drum shaft 3 is transmitted to the photosensitive drum 1 via the flange 2. Further, since the grounding member 4 also rotates together with the photosensitive drum shaft 3 and the flange 2, it is not necessary to consider a problem such as friction between the photosensitive drum shaft 3 and the ground brush 5. On the other hand, in the latter case, the photosensitive drum shaft 3 has the flange 2
Although not shown, the flange 2 itself is composed of a gear or the like, and is directly driven to transmit the rotational force to the photosensitive drum 1. In this case, the abrasion due to friction between the fixed photosensitive drum shaft 3 and the ground brush 5 of the ground member 4 rotating together with the flange 2 poses a problem, but the material of the ground member 4 is not wear-resistant. By using a high one, this problem can be solved easily. From the above, it is desirable that the grounding member 4 is made of a material having conductivity and high flexibility and wear resistance, and a metal spring member such as phosphor bronze is most suitable. But,
From the viewpoint of reliable grounding, the material of the grounding member 4 may be at least one having conductivity, and may be, for example, another metal, a conductive rubber material, a resin, or the like. FIG. 2 is a diagram showing a modification of the first embodiment of the present invention. In the figure, the same parts as those in FIG. 1 are designated by the same reference numerals, and the duplicate description will be omitted.

In this embodiment, the ground brush is not formed integrally with the ground member 4, but a plurality of ground brush pieces 9 as shown in the drawing are arranged on the ground member 4, and the restraining ring 1 is provided.
It is configured by fixing at 0. here,
If the ground brush piece 9 is fixed to the ground member 4 and then comes into contact with the photosensitive drum shaft 3 while being bent, the shape and number of the ground brush pieces 9 are the same as those in this embodiment. It is not limited. The detailed description of this embodiment is the same as that of the first embodiment shown in FIG. FIG. 3 is a diagram showing a second embodiment of the present invention. In the figure, the same parts as those in FIG. 1 are designated by the same reference numerals, and the duplicate description will be omitted.

In this embodiment, the photosensitive drum shaft 3 is a drive shaft for rotating the photosensitive drum 1, and the photosensitive drum shaft 3 is simply inserted into the flange 2. Further, a groove portion 11 into which the ground brush 5 of the ground member 4 is fitted is formed on the side surface of the end portion of the photosensitive drum shaft 3.

According to this structure, after the grounding member 4 is fitted into the photosensitive drum shaft 3 and then the photosensitive drum shaft 3 is rotated, one of the ground brushes 5 falls into the groove portion 8. Is becoming As a result, the rotational force when the photosensitive drum shaft 3 rotates is transmitted to the ground member 4 via the ground brush 12 fitted in the groove portion 9, and further transmitted from the ground member 4 to the photosensitive drum 1. In the figure, the groove portion 8 on the photosensitive drum shaft 3 is provided at only one place, but these may be provided at a plurality of places as long as they are provided at positions where the plurality of ground brushes 5 can be reliably inserted. In this embodiment, a grounding member having a grounding brush piece according to the modification of the first embodiment may be used.

4 and 5 show a third embodiment of the present invention. In the figure, the same parts as those in FIGS. 1 and 2 are designated by the same reference numerals, and the duplicate description will be omitted.

In the first and second embodiments described above, in order to surely press the grounding member 4 against the inner peripheral surface of the photosensitive drum 1, the side wall 7 is provided on the outer periphery of the grounding member 4. On the other hand, in this embodiment, the ground member 4
Is kept flat, and the ring-shaped holding member 13 having conductivity is interposed so that the ground member 4 and the inner peripheral surface of the photosensitive drum 1 are electrically connected to each other. Since the restraining member 13 also plays a role of fixing the ground member 4 on the flange 2, the fixing pin 8 as shown in the first and second embodiments in this embodiment is also provided.
Is not particularly required.

According to this structure, when the grounding member 4 is manufactured, the work for providing the side wall portion 7 on the outer periphery of the grounding member 4 is not required, so that the workability of the grounding member 4 can be improved. Also in this embodiment, a grounding member having a grounding brush piece according to the modification of the first embodiment may be used.

In the embodiment described above, even if the flanges provided at both ends of the photosensitive drum are made of a non-conductive material, the charge on the photosensitive drum is transferred to the shaft of the photosensitive drum through the ground brush according to the present invention. It is possible to let it escape, and thus the photosensitive drum can be reliably grounded.

[0023]

As described above, according to the present invention,
By discharging the charge on the photosensitive drum to the photosensitive drum shaft via the grounding member, it is possible to provide a photosensitive drum device capable of reliably grounding the photosensitive drum.

Further, since the ground brush of the ground member comes into contact with the photosensitive drum while flexing, the repulsive force pre-presses the photosensitive drum in the axial direction of the photosensitive drum and in the radial direction of the photosensitive drum, and the vibration caused by the rotation of the photosensitive drum is generated. The photosensitive drum device can be suppressed.

Further, when the photosensitive drum shaft is a drive shaft for rotating the photosensitive drum, the ground brush of the ground member is inserted into the groove portion provided on the photosensitive drum shaft so that the ground member is interposed. As a result, the photosensitive drum device can be configured to transmit the rotational force of the photosensitive drum shaft to the photosensitive drum.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a modification of the first embodiment of the present invention.

FIG. 3 is a diagram showing a second embodiment of the present invention.

FIG. 4 is a diagram showing a third embodiment of the present invention.

FIG. 5 is a diagram showing a third embodiment of the present invention.

[Explanation of symbols]

 1 Photosensitive Drum 2 Flange 3 Photosensitive Drum Shaft 4 Grounding Member 5 Grounding Brush 6 Groove 7 Sidewall 8 Fixing Pin 9 Grounding Brush Piece 10 Holding Ring 11 Groove 12 Grounding Brush 13 Fitted in Groove

Claims (3)

[Claims] 1. A grounding member having a grounding brush electrically connected to the inner peripheral surface of the photosensitive drum and having a grounding brush that flexibly contacts the photosensitive drum shaft engaged with the photosensitive drum. Characteristic photosensitive drum device. 2. The photosensitive drum device according to claim 1, wherein at least one of the ground brushes is fitted into a groove provided on the photosensitive drum shaft. 3. The photosensitive drum device according to claim 1, wherein the grounding member is electrically connected to an inner peripheral surface of the photosensitive drum via a conductive suppressing member.