JPH04282681A - Structure of photosensitive body drum and its grounding and grounding method for image forming device - Google Patents

Abstract

PURPOSE:To reduce the number of parts required for grounding and to reduce the cost. CONSTITUTION:A grounding member 30 is provided in the photosensitive drum 15, where a shaft part 34 is provided integrally with the grounding member. A top end of the shaft part 34 is made to protrude outside passed through a through-hole 27 of a cylindrical member 22 that is fitted to a tip part of the photosensitive drum 15. Then, when the photosensitive body 15 is fitted to a main body of the image forming device, the top end of the cylindrical member 22 is brought into contact with an electrically conductive member 44 of the main body of the image forming device.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive drum installed in an image forming apparatus such as a copying machine, and its grounding structure and method.

0002

2. Description of the Related Art FIG. 6 shows a grounding structure of a photosensitive drum 90 in a conventional image forming apparatus. In the figure, a through hole 91 is provided at the center of the end of the photoreceptor drum 90.
A cylindrical member 92 with flanges is attached thereto, and a ground plate 94 is provided inside the photoreceptor drum 90 in contact with the inner peripheral surface thereof. On the other hand, a grounded metal side plate 96 is disposed on the image forming apparatus main body side, and a ground pin 98 is protruded from a predetermined position of the side plate 96. This ground pin 98 is inserted into the through hole 91 of the flanged cylindrical member 92. The photosensitive drum 90 is assembled at a predetermined position in the main body of the image forming apparatus with the tip of the grounding pin 98 substantially in point contact with the grounding plate 94 .

0003

[Problem to be solved by the invention] In order to obtain the above structure,
First, a ground pin 98 is provided protrudingly at a predetermined position on the side plate 96, and this ground pin 98 is inserted into the through hole of the flanged cylindrical member 92.
The process of assembling the photosensitive drum 90 is difficult because the photosensitive drum 90 must be attached to the main body of the image forming apparatus while passing through the photosensitive drum 1. Furthermore, since the photosensitive drum 90 rotates relative to the main body of the image forming apparatus, the ground pin 98 must come into approximately point contact with the center of the ground plate 94, and therefore accurate positioning of the ground pin 98 is required. Therefore, according to this grounding structure and method, mounting of the photoreceptor drum 90 requires a lot of effort, and there is a drawback that the cost is likely to be high, and a solution to these problems has been a problem.

[0004] Especially in recent years, image forming devices such as copying machines,
Efforts are being made to popularize it not only as a business device installed in offices, etc., but also as a household device that can be easily used by individuals in general households. There is an urgent need to significantly reduce the number of parts and costs overall.

SUMMARY OF THE INVENTION In view of the above circumstances, it is an object of the present invention to provide a photosensitive drum in an image forming apparatus, a grounding structure thereof, and a grounding method, which can reduce the number of parts and cost.

[0006]

[Means for Solving the Problems] The present invention provides a photosensitive drum mounted on an image forming apparatus, which includes a drum body and a cylindrical member provided at an end of the drum body and having an axial through hole. The whole is integrally molded with conductive material,
a grounding member having a drum contact portion and a shaft portion extending substantially perpendicularly to the drum contact portion, the drum contact portion contacting the inner surface of the drum body, and the tip end of the shaft portion contacting the cylindrical member. The grounding member is disposed within the drum body so as to protrude to the outside through the through hole of the drum body (claim 1).

[0007] Further, the present invention includes the photosensitive drum and a conductive member that is provided on the main body side of the image forming apparatus and is grounded, and the tip of the shaft of the photosensitive drum is in contact with the conductive member. This photosensitive drum is mounted on the main body of the image forming apparatus (Claim 3).

The present invention also provides a method for obtaining the above-mentioned grounding structure, in which a part of the grounding member made of a conductive material is bent approximately at right angles to form a shaft portion, and the shaft portion is formed into a cylinder having an axial through hole. The earthing member is provided inside the photoreceptor drum in contact with the cylindrical member by passing through the through hole of the member and protruding to the outside of the cylindrical member. When the photosensitive drum is attached to the end of the image forming apparatus, the tip of the shaft is brought into contact with a conductive member connected to ground (claim 5).

[0009] Furthermore, a spring made of a conductive member that can be expanded and contracted in the axial direction is attached to the tip of the shaft (claim 2).
), if the tip of the spring is brought into pressure contact with the conductive member (claims 4 and 6), better effects as described below can be obtained.

0010

[Function]According to the configurations of claims 1, 3, and 5, there is no need for the conventional protruding ground pin, and by simply mounting the photoreceptor drum on the main body of the image forming apparatus, the inside of the photoreceptor drum can be By bringing the tip of the shaft integrally formed into the grounding member into approximately point contact with the conductive member on the image forming apparatus main body side,
Grounding of the photoreceptor drum is realized. Furthermore, claim 2
, 4 and 6, the spring attached to the tip of the shaft presses against the conductive member with its elastic force, so that the electrical connection between the grounding member and the conductive member is more secure. will be exposed.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. 1 to 3.

FIG. 2 is a schematic diagram showing an example of a copying machine (image forming apparatus) in which the present invention is implemented.

[0013] This device has an upper housing 1 and a lower housing 2 made of synthetic resin or the like, and a main housing is formed by joining the two, and the upper part of the housing includes:
A document table 11 and a document presser 12 that move in the left-right direction in the figure are arranged. An optical system consisting of an exposure lamp 13 and a condensing lens 14 is arranged in the upper part of the housing, and this optical system illuminates the image of the document on the document table 11 onto the circumferential surface of the photoreceptor drum 15. It is now possible to do so.

Image forming means such as a main charger (charging device) 16, a developing device 10, a transfer separation device 17, and a cleaning device 18 are arranged around the photosensitive drum 15. The image formed on the photosensitive drum 15 is transferred to a transfer paper fed from a paper feed tray 20 by a transfer separation device 17, and then the transfer paper passes through a fixing device 19 and is discharged onto an output tray 21. be done.

Next, the grounding structure of the photosensitive drum 15 will be explained based on FIGS. 1 and 3.

The photosensitive drum 15 has a drum body 23 made of aluminum or the like.
A cylindrical member 22 made of synthetic resin or the like is attached to the end of 3. This cylindrical member 22 has a cylindrical portion 24
, a flange portion 26 having approximately the same diameter as the drum body 23, and a fitting portion 28 having a smaller diameter than the flange portion 26. A notch 25 is formed in the cylindrical portion 24 for mounting a drive transmission gear (not shown). An axial through hole 27 is provided in both the cylindrical portion 24 and the flange portion 26, and a diametrical through groove 29 (see FIG. 3) communicating with the through hole 27 is provided in the fitting portion 28. It is provided.

Further, inside the drum body 23, there is a grounding member 30 integrally formed of a conductive material such as metal.
is now set up. This grounding member 30 has a drum contact plate 32 having a substantially circular shape, and a pair of slits 31 are provided at appropriate positions on this drum contact plate 32, thereby forming a bendable piece 33 in the center. A shaft portion 34 is formed by bending a portion of this flexible piece 33 at a substantially right angle. This shaft portion 34 is
It has a longer overall length than the cylindrical member 22, its both side edges are bent at right angles to form ribs 36, and its tip has a pointed shape.

At both upper and lower ends of the drum contact plate 32,
A contact portion 38 is formed respectively. Each contact portion 38 protrudes slightly outward in the radial direction from the other peripheral portions, and its tip portion has a sharply pointed shape. Also,
Engagement holes 42 as shown in FIG. 3 are bored at appropriate positions on the drum contact plate 32, while engagement holes 42 are formed at predetermined positions of the fitting portion 28 in the cylindrical member 22. A possible engagement projection 40 is provided.

On the other hand, a side plate (conductive member) 4 made of a conductive material such as metal is provided at a predetermined position at the rear of the main body of the image forming apparatus.
4 is provided, and this side plate 44 is grounded.

Next, the cylindrical member 22 and the ground member 30
The mounting procedure and the grounding method of the photosensitive drum 15 will be explained.

First, the shaft portion 34 of the grounding member 30 is inserted into the through hole of the cylindrical member 22 from the fitting portion 28 side, and the drum contact plate 32 is engaged with the engaging hole 42 and the engaging protrusion 40.
is fixed to the surface of the fitting portion 28 by means of adhesive or the like. In this state, the tip of the shaft portion 34 is connected to the cylindrical portion 22 of the cylindrical member 22.
It will be in a state where it protrudes outward from the end face of.

Next, by fitting the fitting portion 28 into the rear end opening of the drum body 23 and fixing the flange portion 26 to the rear end surface of the drum body 23, the cylindrical member 22 is attached to the rear end of the drum body 23. Installing. During this installation, both contact portions 38 of the drum contact plate 32 are pushed in while scratching and damaging the inner peripheral surface of the drum body 23, so that the drum contact plate 32 and the drum body 23 come into contact at the scratched portions. will be fulfilled.

By assembling the photosensitive drum 15 at a predetermined position within the main body of the image forming apparatus with the grounding member 30 and the cylinder member 22 attached in this manner, the tip of the shaft portion 34 protruding from the rear end is removed. comes into contact with the side plate 44 on the image forming apparatus main body side. Due to this contact, the photoreceptor drum 15
becomes grounded. Note that when the tip of the shaft portion 34 contacts the side plate 44, this tip receives a slight reaction force from the side plate 44, but this reaction force is absorbed by the bending of the bending piece 33 of the grounding member 30.

According to the structure and method described above, when the photoreceptor drum 15 is mounted on the main body of the image forming apparatus, the tip of the shaft portion 34 protruding from the photoreceptor drum 15 can be attached to any arbitrary position on the side plate 44. Since grounding can be done by simply touching the spot, there is no need to protrude and position a ground pin (earth pin 98 in FIG. 4) as required in the past. The work of mounting the drum 15 is also facilitated. Therefore, compared to the structure shown in FIG. 6, the number of parts and cost required for grounding can be reduced.

Next, a second embodiment will be explained based on FIG. 4.

Here, a recess 46 is formed in the side plate 44 at a position corresponding to the tip of the shaft 34, and the tip of the shaft 34 is brought into contact with the recess 46. According to such a structure, the contact between the tip of the shaft portion 34 and the side plate 44 is maintained in a more stable state.

Next, a third embodiment will be explained based on FIG. 5.

Here, before the photosensitive drum 15 is mounted on the main body of the image forming apparatus, a conductive member such as metal is attached to the tip of the shaft portion 34 and is expandable and retractable in the axial direction of the shaft portion 34. A formed spring 48 is attached, and when the photoreceptor drum 15 is attached, the tip of the spring 48 is brought into pressure contact with the side plate 44 by its elastic force. According to such a structure, the side plate 44 side and the ground member 30 side (actually the spring 48), the electrical connection between the two can be made more reliable.

In the present invention, the specific shape of the grounding member does not matter; the grounding contact portion may have a shape capable of contacting the inner circumferential surface of the drum body, and the shaft portion may protrude to the outside through the through hole of the cylindrical member. If the shape is such that the effect can be obtained.

Further, when the side plate 44 is made of an insulating material such as synthetic resin, a conductive member is separately provided on the surface of the side plate 44, and this is grounded to connect the shaft portion 34.
All you have to do is contact it.

[0031]

[Effects of the Invention] As described above, according to the present invention, the following effects can be obtained.

First, in the structure described in claims 1, 3, and 5, a shaft portion is integrally formed in the grounding member provided on the photoreceptor drum side, and this shaft portion is inserted into the through hole of the cylindrical member at the end of the photoreceptor drum. When the photoreceptor drum is mounted on the image forming apparatus main body, the cylindrical member is brought into contact with the conductive member on the image forming apparatus main body side, so there is no need to use the conventional ground pin. In addition to eliminating the need for protrusion work and positioning work, the photoreceptor drum can be easily attached to the main body of the image forming apparatus, thereby reducing the number of parts and cost required for grounding the photoreceptor drum. There is an effect that can be done.

Furthermore, in the structures described in claims 2, 4, and 6, since the spring contacts the conductive member with the elastic force generated by its compressive deformation, the electrical connection between the grounding member and the conductive member is established through the spring. This has the effect of making the connection more reliable.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional side view showing the grounding structure of a photosensitive drum in a first embodiment of the present invention.

FIG. 2 is a schematic front view showing an example of an image forming apparatus including the photosensitive drum.

FIG. 3 is a perspective view of a ground member and a cylindrical member attached to the photoreceptor drum. Ru.

FIG. 4 is a cross-sectional side view showing the grounding structure of a photosensitive drum in a second embodiment of the present invention.

FIG. 5 is a cross-sectional side view showing a grounding structure of a photosensitive drum in a third embodiment of the present invention.

FIG. 6 is a cross-sectional side view showing an example of a conventional grounding structure of a photoreceptor drum.

[Explanation of symbols]

15 Photoreceptor drum 22 Cylinder member 23 Drum body 24 Cylindrical member 27 Through hole 30 Ground member 32 Drum contact plate 34 Shaft part 44 Side plate (conductive member) 48 Spring

Claims (6)

[Claims] 1. A photoreceptor drum installed in an image forming apparatus, which is made up entirely of a drum body, a cylindrical member provided at the end of the drum body and having an axial through hole, and a conductive material. a grounding member integrally molded and having a drum contact portion and a shaft portion extending substantially perpendicularly to the drum contact portion; 1. A photosensitive drum for an image forming apparatus, characterized in that a grounding member is disposed within a drum main body with a portion protruding to the outside through a through hole of the cylindrical member. 2. In the photosensitive drum of the image forming apparatus according to claim 1, a spring made of a conductive member that is expandable and contractible in the axial direction of the shaft portion is attached to the tip end of the shaft portion. A photosensitive drum in a featured image forming apparatus. 3. A photoreceptor drum according to claim 1, and a conductive member provided on the main body side of the image forming apparatus and grounded, wherein the tip of the shaft of the photoreceptor drum contacts the conductive member. 1. A grounding structure for a photoreceptor drum in an image forming apparatus, wherein the photoreceptor drum is mounted on an image forming apparatus main body. 4. The photosensitive drum according to claim 1, a conductive member provided on the side of the main body of the image forming apparatus and grounded, and a conductive member that extends and contracts in the axial direction of the shaft. A photosensitive drum in an image forming apparatus, characterized in that a spring made of an electrically conductive material is attached to the photosensitive drum, and the photosensitive drum is attached to the main body of the image forming apparatus in a state in which the tip of the spring is in pressure contact with the electrically conductive member. Earthing structure of body drum. 5. A method for grounding a photoreceptor drum mounted on an image forming apparatus, wherein a portion of a grounding member made of a conductive material is bent approximately at right angles to form a shaft portion, and the shaft portion is aligned in the axial direction. The earthing member is provided inside the photoreceptor drum in a state in which it is in contact with the photoreceptor drum by passing through the through hole of the cylindrical member and protruding to the outside of the cylindrical member. The photosensitive drum is attached to the end of the drum body of the image forming apparatus, and when the photosensitive drum is attached to the image forming apparatus body, the tip of the shaft is brought into contact with a conductive member connected to ground. How to ground the photoreceptor drum in a forming device. 6. In the method for grounding a photoreceptor drum in an image forming apparatus according to claim 5, before the photoreceptor drum is mounted on the main body of the image forming apparatus, the tip of the shaft is grounded in the axial direction of the shaft. An image forming apparatus characterized in that a spring made of a stretchable conductive member is attached, and a tip of the spring is brought into pressure contact with the conductive member when the photoreceptor drum is attached to the image forming apparatus main body. How to ground the photoreceptor drum.