JP2995272B2 - Photosensitive drum in image forming apparatus, grounding structure thereof, and grounding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art FIG. 6 shows a ground structure of a photosensitive drum 90 in a conventional image forming apparatus. In the figure, a through hole 91 is provided at the end of the photosensitive drum 90 at the center.
Is mounted, and a ground plate 94 is provided inside the photosensitive drum 90 so as to be 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 at a predetermined position thereof. The ground pin 98 is inserted into the through hole 91 of the flanged tubular member 92. The photosensitive drum 90 is mounted at a predetermined position in the main body of the image forming apparatus with the tip of the ground pin 98 substantially in point contact with the ground plate 94.

[0003]

In order to obtain the above structure,
First, an earth pin 98 is protruded at a predetermined position of the side plate 96, and this earth pin 98 is inserted into the through hole 9 of the cylindrical member 92 with a flange.
A complicated process such as mounting the photosensitive drum 90 on the main body of the image forming apparatus while passing through 1 is required, and assembling work of the photosensitive drum 90 is difficult. In addition, since the photosensitive drum 90 rotates with respect to the image forming apparatus main body, the ground pin 98 must make substantially point contact with the center of the ground plate 94, so that accurate positioning of the ground pin 98 is required. Therefore, according to the grounding structure and the grounding method, the mounting of the photoconductor drum 90 requires a lot of trouble and there is a disadvantage that the cost tends to be high.

Particularly in recent years, image forming apparatuses such as copying machines have been
Attempts have been made to disseminate not only business equipment installed in offices and the like but also household equipment that can be used easily and privately in ordinary households. There is an urgent need to significantly reduce the number of parts and costs for the whole.

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

[0006]

SUMMARY OF THE INVENTION The present invention relates to a photosensitive drum mounted on an image forming apparatus, comprising: a drum main body; and a cylindrical member provided at an end of the drum main body and having an axial through hole. And, the whole is integrally molded by the conductive material,
A drum contact portion and an earth member having a shaft portion extending in a direction substantially perpendicular to the drum contact portion, wherein the drum contact portion contacts an inner surface of the drum main body, and a tip end of the shaft portion is the cylindrical member. The grounding member is disposed inside the drum main body so as to protrude to the outside through the through hole (claim 1).

Further, the present invention includes the above-mentioned photosensitive drum, and a conductive member provided on the image forming apparatus main body side and grounded, wherein a tip portion of a shaft portion of the photosensitive drum comes into contact with the conductive member. The photosensitive drum is mounted on the image forming apparatus main body (claim 3).

According to the present invention, as a method for obtaining the above-mentioned earthing structure, a part of an earthing member made of a conductive material is bent at a substantially right angle to form a shaft part, and this shaft part is formed into a cylinder having an axial through hole. The grounding member is provided inside the photosensitive drum in a state where the cylindrical member is brought into contact with the photosensitive drum while the cylindrical member is protruded to the outside of the cylindrical member through the through hole of the member. When the photosensitive drum is mounted on the end portion and the photosensitive drum is mounted on the image forming apparatus main body, the tip of the shaft portion is brought into contact with a conductive member connected to the ground.

Further, a spring made of a conductive member that can expand and contract in the axial direction is attached to the tip of the shaft portion (claim 2), and the tip of the spring is pressed against the conductive member. (Claims 4 and 6), more excellent effects as described below can be obtained.

[0010]

According to the structure of the first, third, and fifth aspects of the present invention, it is not necessary to provide a conventional ground pin, and simply mount the photosensitive drum on the main body of the image forming apparatus. By the point of the shaft portion formed integrally with the ground member being substantially in point contact with the conductive member on the image forming apparatus main body side,
Grounding of the photosensitive drum is realized. Further, according to the configuration of the second, fourth, and sixth aspects, the spring attached to the tip of the shaft portion presses against the conductive member by its resilient force, so that the electrical connection between the ground member and the conductive member is made. Will be performed more reliably.

[0011]

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

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

This device has an upper housing 1 and a lower housing 2 made of a synthetic resin or the like, and a main body housing is formed by joining the two together.
A document table 11 and a document presser 12 that move in the left-right direction in the figure are provided. An optical system including an exposure lamp 13 and a condenser lens 14 is arranged at an upper portion in the housing, and irradiates an image of a document on the document table 11 onto a peripheral surface of the photosensitive drum 15 by the optical system. It is supposed to be.

Around the photosensitive drum 15, 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 provided. The image formed on the photosensitive drum 15 is transferred to a transfer sheet fed from a sheet feed tray 20 by a transfer / separation device 17, and then the transfer sheet is discharged onto a discharge tray 21 through a fixing device 19. Is done.

Next, the ground structure of the photosensitive drum 15 will be described with reference to FIGS.

The photosensitive drum 15 has a drum main body 23 made of aluminum or the like.
A cylindrical member 22 made of a synthetic resin or the like is attached to an end of the third member 3. The cylindrical member 22 is formed of the cylindrical portion 2.
4, a flange portion 26 having substantially the same diameter as the drum main body 23, and a fitting portion 28 having a smaller diameter than the flange portion 26 are provided. A cutout 25 for mounting a drive transmission gear (not shown) is formed in the cylindrical portion 24. 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 formed in the fitting portion 28. Is provided.

An earth member 30 integrally formed of a conductive material such as metal is integrally formed in the drum main body 23.
Are arranged. This ground member 30
Has a substantially circular drum contact plate 32, and a pair of slits 31 is provided at an appropriate position on the drum contact plate 32 to form a bendable flexure 33 at a central portion. The shaft part 34 is formed by bending a part of 33 at a substantially right angle. This shaft portion 34
Has an overall length greater than that of the tubular member 22, and its side edges are bent at right angles to form ribs 36, and the tip has a pointed shape.

At the upper and lower ends of the drum contact plate 32,
Each of the contact portions 38 is formed. Each contact part 38
Protrudes slightly radially outward from the other peripheral portions, and has a sharply pointed distal end. An engaging hole 42 as shown in FIG. 3 is formed at an appropriate position on the drum contact plate 32.
An engagement protrusion 40 engageable with the engagement hole 42 is provided at a predetermined position of the fitting portion 28 in FIG.

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

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

First, the shaft portion 34 of the ground 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 while the engaging hole 42 and the engaging projection 40 are engaged.
Is fixed to the surface of the fitting portion 28 by means such as adhesion. In this state, the tip of the shaft portion 34 is
Is projected outward from the end face of.

Next, the fitting portion 28 is fitted into the rear end opening of the drum main body 23, and the flange portion 26 is fixed to the rear end surface of the drum main body 23, so that the cylindrical member 22 is attached to the rear end of the drum main body 23. Installing. At the time of this mounting, the contact portions 38 of the drum contact plate 32 are pushed in while scratching and scratching the inner peripheral surface of the drum main body 23, so that the contact between the drum contact plate 32 and the drum main body 23 occurs at the portion where the flaw is formed. Is fulfilled.

By attaching the photosensitive drum 15 to a predetermined position in the main body of the image forming apparatus with the ground member 30 and the cylindrical member 22 attached in this manner, the tip of the shaft portion 34 protruding from the rear end is provided. Contacts the side plate 44 on the image forming apparatus main body side. By this contact, the photosensitive drum 15
Is grounded. When the tip of the shaft 34 contacts the side plate 44, the tip receives a slight reaction force from the side plate 44, but this reaction is absorbed by the bending of the bending piece 33 of the ground member 30.

According to the above-described structure and method, when the photosensitive drum 15 is mounted on the main body of the image forming apparatus, the tip of the shaft 34 protruding from the photosensitive drum 15 can be arbitrarily set on the side plate 44. Since the grounding can be performed only by contacting the portion, the work of projecting and positioning the ground pin (ground pin 98 in FIG. 4) as in the related art is unnecessary, and the photosensitive member to the image forming apparatus main body is not required. The mounting work of the drum 15 is also facilitated. Therefore, compared to the structure as shown in FIG. 6, the number of parts required for grounding and the cost can be reduced.

Next, a second embodiment will be described with reference to FIG.

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 distal end portion of the shaft portion 34 and the side plate 44 is maintained in a more stable state.

Next, a third embodiment will be described with reference to FIG.

Here, before the photosensitive drum 15 is mounted on the main body of the image forming apparatus, a conductive member made of metal or the like, which is expandable and contractible in the axial direction of the shaft portion 34, is attached to the tip of the shaft portion 34. The formed spring 48 is mounted, and the distal end of the spring 48 is pressed against the side plate 44 by the elastic force when the photosensitive drum 15 is mounted. According to such a structure, not only the bending deformation of the bending piece 33 shown in FIG. 3 but also the resilient force due to the compression deformation of the spring 48 is applied to the side plate 44 and the ground member 30 (actually, the spring). 48), the electrical connection between the two can be further ensured.

In the present invention, regardless of the specific shape of the ground member, the ground contact portion has a shape capable of contacting the inner peripheral surface of the drum body, and the shaft portion protrudes outside through the through hole of the cylindrical member. With such a shape, the effect can be obtained.

When the side plate 44 is formed of an insulating material such as a synthetic resin, a separate conductive member is provided on the surface of the side plate 44, and the conductive member is grounded to ground the shaft portion 34.
Should be contacted.

[0031]

As described above, according to the present invention, the following effects can be obtained.

According to the first, third, and fifth aspects of the present invention, a shaft is formed integrally with a ground member provided on the photosensitive drum side, and the shaft is formed in a through hole of a cylindrical member at an end of the photosensitive drum. Through which the cylindrical member is brought into contact with the conductive member of the image forming apparatus main body when the photosensitive drum is mounted on the image forming apparatus main body. The projecting operation and the positioning operation are not required, and the photosensitive drum can be easily mounted on the main body of the image forming apparatus. Therefore, the number of parts required for grounding the photosensitive drum and the cost can be reduced. There is an effect that can be done.

Further, in the configuration according to the second, fourth, and sixth aspects, since the spring comes into contact with the conductive member by the elastic force of its compression deformation, the electrical connection between the grounding member and the conductive member is made via this spring. This has the effect of making the connection more reliable.

[Brief description of the drawings]

FIG. 1 is a sectional side view showing a ground structure of a photosensitive drum according to a first embodiment of the present invention.

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

FIG. 3 is a perspective view of a ground member and a cylindrical member mounted on the photosensitive drum. You.

FIG. 4 is a sectional side view showing a ground structure of a photosensitive drum according to a second embodiment of the present invention.

FIG. 5 is a sectional side view showing a ground structure of a photosensitive drum according to a third embodiment of the present invention.

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

[Explanation of symbols]

 Reference Signs List 15 photosensitive drum 22 cylinder member 23 drum main body 24 cylinder member 27 through hole 30 ground member 32 drum contact plate 34 shaft portion 44 side plate (conductive member) 48 spring

────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yukihiro Aikawa 1-2-28 Tamazo, Chuo-ku, Osaka-shi Inside Mita Kogyo Co., Ltd. (72) Inventor Satoshi Ishii 1-2-28 Tamazo, Chuo-ku, Osaka-shi Mita Within Industrial Co., Ltd. (56) References Japanese Utility Model 60-112261 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03G 21/00 350-352 G03G 15/00 550 G03G 21 / 16-21/18

Claims (6)

(57) [Claims] 1. A photosensitive drum mounted on an image forming apparatus, comprising: a drum main body; a cylindrical member provided at an end of the drum main body and having an axial through hole; An earth member having a drum contact portion and a shaft portion extending in a direction substantially perpendicular to the drum contact portion, the drum contact portion being in contact with the inner surface of the drum body, and a tip of the shaft portion A photosensitive drum in the image forming apparatus, wherein a ground member is provided in the drum main body in a state where the portion projects outside through a through hole of the cylindrical member. 2. A photosensitive drum in the image forming apparatus according to claim 1, wherein a spring made of a conductive member that can expand and contract in the axial direction of the shaft is attached to a tip of the shaft. A photosensitive drum in the image forming apparatus. 3. The photosensitive drum according to claim 1, further comprising: a conductive member provided on the image forming apparatus main body side and grounded, wherein a tip of a shaft portion of the photosensitive drum contacts the conductive member. The photosensitive drum is mounted on the main body of the image forming apparatus in such a state that the photosensitive drum is grounded in the image forming apparatus. 4. A photosensitive drum according to claim 1, further comprising a conductive member provided on the image forming apparatus main body side and grounded, and extending and contracting at a tip end of said shaft in the axial direction of said shaft. A photosensitive spring in the image forming apparatus, wherein the photosensitive drum is mounted on the image forming apparatus main body in a state where a spring made of a possible conductive member is mounted, and a tip end of the spring is pressed against the conductive member. Earth structure of body drum. 5. A method for grounding a photosensitive drum mounted on an image forming apparatus, wherein a part of a ground member made of a conductive material is bent at substantially right angle to form a shaft, and the shaft is formed in an axial direction. In a state in which the earth member is provided in contact with the inside of the photoreceptor drum in a state where the earth member is protruded to the outside of the cylindrical member through the through hole of the cylindrical member having the through hole,
The cylindrical member is mounted on the end of the drum main body of the photosensitive drum, and when the photosensitive drum is mounted on the image forming apparatus main body, the tip of the shaft is brought into contact with a conductive member connected to ground. A method for grounding a photosensitive drum in an image forming apparatus. 6. A grounding method for a photosensitive drum in an image forming apparatus according to claim 5, wherein the photosensitive drum is attached to a tip end of the shaft in an axial direction of the shaft before mounting the photosensitive drum to an image forming apparatus main body. An image forming apparatus, wherein a spring made of a stretchable conductive member is mounted, and when the photosensitive drum is mounted on the image forming apparatus main body, a tip end of the spring is pressed against the conductive member. Grounding method of the photosensitive drum in the above.