JP2003005582A - Photoreceptor drum - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain self-excited vibration of a contact piece sliding in contact with a fixed shaft and to prevent abnormal sound from being produced on a ground plate for grounding between the photoreceptor and the fixed shaft of a photoreceptor drum. SOLUTION: As for a flange member 23 attached to the end of the photoreceptor 21 of the photoreceptor drum, many pawl parts 29 are formed to project on the periphery and the contact piece 28 is provided for a small- diameter part 16 on the ground plate 27 setting conduction between the fixed shaft 15 and the photoreceptor 21. An elastic body 26 is arranged in the recessed part 25 of the member 23 for the contact piece 28 and the contact piece 28 is positioned at the small-diameter part 16 in a state where it presses the elastic body 26. Therefore, even if the self-excited vibration is caused when the contact piece 28 slides in contact with the small-diameter part 16, damping action is applied by the elastic body 26 so as to prevent the abnormal sound from being produced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a photoconductor drum used in an image forming apparatus, and more particularly, it is possible to satisfactorily set the ground between the photoconductor part of the photoconductor drum and a fixed shaft, and to make noise The present invention relates to a device capable of preventing the occurrence of

[0002]

2. Description of the Related Art Generally, in an image forming apparatus using an electrophotographic system such as an electrophotographic copying machine, a facsimile machine, a printer, etc., an electrostatic latent image is formed on a photosensitive drum by using an optical writing means. Toner is supplied from the developing device to the electrostatic latent image to make it visible as a toner image. Then, the toner image formed on the photosensitive drum is transferred onto a sheet by using a transfer unit, and the sheet on which the toner image is transferred is fixed through a fixing device to create a copy. In the photoconductor drum, the charge of the photoconductor layer is removed when an electrostatic latent image is formed by irradiating light of an image by the optical writing means after uniformly charging the drum. If not sufficiently done, an image defect will occur, so a means is provided for allowing the charged charges of the photoconductor to escape to the device frame via the fixed shaft.

As a method of grounding, a grounding plate mounted on a flange member arranged at the end of the photosensitive drum is slidably contacted with the drum shaft to ground it. The ground plate used as the grounding unit is provided rotatably with respect to the fixed shaft together with the flange member supporting the photoconductor drum, and is radially provided on the inner peripheral surface of the photoconductor on the outer peripheral portion of the disk-shaped member. A claw portion for pressure contact is provided so that the contact piece slides on the fixed shaft. By pushing the flange member to which the earth plate is attached from the end of the drum, the elastic action of the claw portion of the earth plate with respect to the inner peripheral portion of the drum causes the earth plate to slidably contact the inner peripheral portion of the drum. At this time, the claw portion of the ground plate breaks the alumite layer on the inner peripheral portion of the drum to electrically connect the photoconductor of the photoconductor drum to the grounded device frame through the ground plate. , The electrostatic charges on the photoconductor are released to form an electrostatic latent image.

[0004]

Lubricating means, such as applying a lubricant such as conductive grease, is provided at the portion where the contact piece of the earth plate slides on the fixed shaft.
The sliding action at the portion where the metals slide with each other and the conducting action can be performed in a good state. However, when applying conductive grease to the sliding part, if the amount of grease applied is not sufficient, or if the grease solidifies or flows to other parts over time, the sliding This causes a problem that the lubrication performance at the contact portion changes. Therefore, when the photoconductor drum is rotated with respect to the fixed shaft, the contact piece slides in contact with the fixed shaft without sufficient lubricant, so that the contact piece slides smoothly on the fixed shaft. Without doing so, the ground plate may cause self-excited vibration (chattering) through the contact piece, and a high-frequency abnormal noise may be generated. Then, because the grounding action between the photoconductor drum and the fixed shaft is not performed well, the inconvenience that the action of removing the charge of the photoconductor drum is not performed well occurs, and an abnormal noise is generated by the user. It may cause discomfort to the user or may cause such abnormal noise to make the device less reliable.

It is an object of the present invention to provide means for suppressing the generation of abnormal noise at the sliding contact portion of the ground plate and maintaining the noise suppressing effect for a long time.

[0006]

According to the present invention, there is provided a photosensitive drum, a flange member fixed to an end portion of the photosensitive drum, a fixed shaft inserted through the flange member and supporting the photosensitive drum, The present invention relates to a photoconductor drum provided with a ground plate fixed to a flange member and grounding the photoconductor drum. According to a first aspect of the present invention, a sliding contact piece for electrically connecting the photosensitive drum and the fixed shaft is integrally formed on the ground plate, and the sliding contact piece is attached so as to be pressed against the shaft. An auxiliary member is arranged to keep the sliding contact piece in contact with the fixed shaft. Further, as described above, since the self-excited vibration of the contact piece that electrically connects the ground plate and the fixed shaft can be suppressed, the generation of abnormal noise can be prevented. Further, since the contact piece is prevented from being separated from the fixed shaft by the auxiliary member, it is possible to appropriately perform the action of releasing the charged electric charge of the photosensitive drum to the ground.

The invention of claim 2 is characterized in that the auxiliary member is formed integrally with the flange member. Since the auxiliary member is formed integrally with the flange member, the number of parts is small, and the work of assembling the photosensitive drum can be easily performed. The invention of claim 3 is characterized in that the auxiliary member is an elastic body arranged in a recess provided in the flange member. Further, by using the elastic member as the auxiliary member, when the contact piece tries to generate self-excited vibration, the elastic member can absorb the vibration, and the effect of suppressing the generation of abnormal noise is better. Can be demonstrated. The invention of claim 4 is characterized in that the sliding contact piece is pressed against a small-diameter portion formed on the fixed shaft.
Therefore, by applying a lubricant to the small diameter portion of the fixed shaft, it is possible to favorably maintain the action of the fixed shaft to hold a lubricant such as grease, and the grease does not diffuse over time, The noise prevention effect can be maintained.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The configuration of the apparatus of the present invention will be described with reference to the illustrated example. Image forming apparatus 1 shown in FIG.
Indicates a device configured as a copying machine or a facsimile device, and the reading unit 2 is arranged above the recording unit 3,
The image information of the original read by the reading unit 2 is transmitted to the recording unit 3, and the recording unit 3 makes a copy. Further, when the image forming apparatus 1 is configured as a facsimile apparatus, the image information obtained by the reading unit is transmitted to another facsimile apparatus through a telephone line, or the information received from the other facsimile apparatus is recorded. It is possible to output as recording paper by a unit, and it can be configured in the same manner as the conventional device. In the image forming apparatus 1, the recording unit 3 may be configured as a printer or the like independently without providing the reading unit in combination.

In the recording section 3 of the image forming apparatus 1, the paper P supported and accommodated on the bottom plate 4a is taken out one by one by the feed roller 5 in the paper feed tray 4 provided at the lower part of the apparatus. The paper is fed toward the recording unit 10 through the paper conveyance path 6 provided with the conveyance roller device 7. In the recording unit 10, a developing device 11, a writing device 13, a cleaning device 14, and a charging unit (not shown) are arranged around a photosensitive drum 20 rotatably supported by a fixed shaft 15. ing.

In the recording section 10, after charging the photosensitive drum 20 uniformly by the charging means, for example, an LED (Light-Emitting Diode) is used.
e), light is irradiated from the optical writing means 13 such as a laser scanner to form an electrostatic latent image on the photoconductor drum 20. And
The toner accommodated in the developing device 11 is supplied from the developing roller 12 toward the electrostatic latent image to make it visible as a toner image, and then comes into contact with the back surface of the sheet conveyed in contact with the photosensitive drum 20. A potential of a predetermined value is applied from the transfer roller 8 to transfer the toner image onto the sheet. The sheet carrying the toner image is fixed by the fixing device 9 and the copy is discharged by the discharge roller device 9a. Further, after the toner image is transferred onto the sheet, the photosensitive drum 2
The toner remaining on the surface of No. 0 is removed by the cleaning device 14 and is charged again by the charging unit so as to correspond to the writing of the image. In the image forming apparatus having the recording unit as a cleanerless device instead of the cleaning device 14, the adhesion force of the residual toner is weakened and the toner is dispersed on the surface of the photoconductor without the cleaning device. It is also possible to provide means for doing so.

A photosensitive drum 20 provided in the recording section 10.
2 can be configured as shown in FIG. 2, and rotatably supports the photosensitive drum 20 with respect to a fixed shaft 15 that is fixedly supported between the device frames 18 of the recording unit. . In the photoconductor drum 20, flange members 22 and 23 are provided at both ends of a cylindrical photoconductor 21, and the fixed shaft 15 of the flange members 22 and 23 is provided.
The inner surface of the hole corresponding to is configured as a sliding part for the shaft,
A drive gear (not shown) is meshed with a gear portion 24 provided at the end of the flange member 22 ... And driven at a constant speed. The photosensitive member 21 is formed of a metal such as aluminum in a cylindrical shape as in the case of the conventional photosensitive member drum, and the surface of the photosensitive member is protected by a photosensitive member layer. A layer is used, and a ground plate 27 is provided to ground the inner surface of the cylinder and the fixed shaft 15 to the ground.

The two flange members 22 and 23 for supporting the photosensitive member 21 are integrally formed by using plastic or the like, and the flange member 23 will be described as an example in FIG. It is configured as shown in FIG. As shown in the figure, the flange member 23 is configured as an integral body by connecting a large-diameter outer cylindrical member 23a and an inner small-diameter cylindrical member 23b by a connecting portion 23c at the end. A gear portion 24 is provided on the outer peripheral portion of the end portion of the radial tubular portion 23a, and the photoconductor 21 is fitted to the outer peripheral portion of the other portion. Further, the hole provided in the small-diameter cylindrical member 23b is formed as a sliding surface for the fixed shaft 15, and is configured to slide on the fixed shaft 15 made of metal and fixedly arranged.

The connecting member 23c for connecting the large and small cylindrical members 23a and 23b has a recess 25 in which the small-diameter cylindrical member 23b is dug in from the tip end side in the mounting direction of the photoconductor.
And an elastic body 26 is mounted in the recess 25. A sponge-like member having an arbitrary hardness is used as the elastic body 26, and the recess 25 of the flange member 23 is filled with the substantially cylindrical elastic body. A small diameter portion 16 is formed on the fixed shaft 15 at a position corresponding to the recess 25, and a contact piece 28 of a ground plate 27 is pressed against the small diameter portion 16 to form a grounding means.

The ground plate 27, as shown,
Consists of a metal with elasticity and conductivity, such as phosphor bronze,
Claws 29 ... Are projectingly formed at a predetermined angle on the periphery of the substantially disk-shaped main body, and the claws 29 project from the inner surface of the photoconductor 21. Since the claws 29 are formed so as to project at a predetermined angle, the ground plate can be smoothly attached to the photoconductor and electrical connection is made to the photoconductor. Further, contact pieces 28 ... Are formed so as to project in a hole corresponding to the fixed shaft 15 of the earth plate 27. The contact pieces 28 and the claw portions 29. Is integrally formed by performing the process of. The contact piece has an arcuate tip, and the arcuate tip is in contact with the small diameter portion of the fixed shaft. As a result, the electrical contact with the drum shaft can be favorably performed, so that the printing quality can be ensured for a long time and the product life can be extended. In particular, even when toner is replenished to a used drum unit and the drum unit is reused, it is possible to favorably maintain the action of releasing the charged charges of the photoconductor. The ground plate 27 is fixedly supported on the flange member 23, and is combined with the photoconductor 21 to form a grounding unit in the photoconductor drum 20.

Fixed shaft 1 using the earth plate 27
5 and the photoconductor 21 are grounded, the contact piece 28 of the ground plate 27 is pressed against the small-diameter portion 16 of the fixed shaft 15 in the state described with reference to FIG.
The inner surface and the fixed shaft 15 are electrically connected. In the ground plate 27 provided in combination with the flange member 23, the contact piece 28 is slidably contacted with the small diameter portion 16 of the fixed shaft 15 inside the recess 25 provided in the flange member 23. Further, the contact piece is formed by a slit formed in the ground plate 27 so as to obtain elasticity. With the fixed shaft 15 combined with the flange member 23, the contact piece 28 pressed by the small diameter portion 16 is pressed by the elastic body 26 provided in the recess 25. As described above, the contact piece 28 is formed so as to bend with respect to the flange member 22 arranged at the end of the photoconductor 20. Therefore, when assembling the photoconductor drum, the flange member 22 can be easily mounted, and even if a force is applied to the ground plate 27 in an unreasonable direction at the time of mounting, the contact piece 28 can be properly deformed and the contact piece 28 and Fixed shaft 15
The contact with the small diameter portion 16 can be surely maintained. Further, the flange member 22 is provided with a recess 25, and the recess 25
Since it is provided so as to fill the cylindrical elastic body 26,
It is possible to prevent the contact piece 28 from vibrating when the photosensitive drum 20 rotates. Therefore, when the contact piece 28 is pressed against the small diameter portion 16, the contact piece 28 is pressed against the elastic body 26 against the pressing action of the contact piece 28 due to the spring property.
By applying the action of restricting by the above, the state in which the contact piece 28 is pressed by the small diameter portion 16 can be favorably set.

In the portion where the contact piece 28 of the earth plate 27 is pressed by the fixed shaft 15, the fixed shaft 1
5 has a small diameter portion 16 formed thereon.
The depth cut into the fixed shaft 15 (diameter of the small diameter portion 16) and the like are set as arbitrary values. Further, the photosensitive drum 20 is fixed to the fixed shaft 1 with respect to the small diameter portion 16.
By applying an arbitrary electrically conductive lubricant before mounting on 5, the sliding resistance when the contact piece 28 slides on the shaft can be made a small value, and the lubrication applied on the shaft can be reduced. Agent
The fixed shaft 15 can be held so as not to flow out to other parts. As described above, the contact piece 28
By providing the lubricant to the small diameter portion 16 on which the sliding contact, the sliding action of the contact piece 28 on the small diameter portion 16 can be favorably maintained when the photosensitive drum 20 is rotated.

Furthermore, even if the contact piece 28 sliding on the small-diameter portion 16 causes a self-excited vibration due to some unpredictable reason, the contact piece 28 is axially moved by the elastic body 26. It is possible to prevent the vibration of the contact piece 28 from increasing due to the action of pressing it toward the side. Further, since the elastic body 26 can absorb the vibration generated in the contact piece 28 and exert a damping action on the contact piece 28,
It is possible to prevent generation of abnormal noise such as chattering noise due to large vibration. Therefore, by providing the elastic body 26 in the recess 25 of the flange member 23, the pressing action of the ground plate 27 against the contact piece 28 can be exhibited well.
Since the structure of the flange member is not complicated, the attachment / detachment action of the photosensitive drum with respect to the apparatus body is not hindered, and the grounding action can be excellently exhibited.

In the photoconductor drum 20, flange members 22 and 23 attached to both ends of the photoconductor 21 are provided.
Can use the same constituent member, but is configured by disposing a ground plate 27 for one flange member 23 and not providing a ground plate for the other flange member 22. It is also possible to configure. In that case, the other flange member 22 may be formed only by a tubular member having a recess, or the frictional resistance value when rotating with respect to the fixed shaft 15 may be reduced. Further, as the ground plate 27 for setting the conduction between the photoconductor and the fixed shaft, the shape of the claw portion 29 for ensuring the conduction to the inner surface of the photoconductor 21 can be arbitrarily configured. Then, the shape and the like of the claw portion can be arbitrarily configured. Further, as the contact piece 28 formed on the ground plate 27, in addition to providing two members as shown in the figure, an arbitrary number of contact pieces can be provided so as to project into the hole in the central portion. The curved shape and thickness of the piece can be arbitrarily formed.

[0019]

The photoconductor drum of the present invention is constructed as described above, and is used for electrically connecting the photoconductor drum and the fixed shaft to the ground plate fixed to the flange member and grounding the photoconductor drum. The sliding contact piece is integrally formed, the sliding contact piece is attached so as to be in pressure contact with the shaft, and the auxiliary member for constantly contacting the sliding contact piece with the fixed shaft is arranged so that the sliding contact piece is fixed to the ground plate. Since it is possible to suppress self-excited vibration of the contact piece that is electrically connected to the shaft, it is possible to prevent abnormal noise. Further, since the contact piece is prevented from being separated from the fixed shaft by the auxiliary member, it is possible to appropriately perform the action of releasing the charged electric charge of the photosensitive drum to the ground.

In addition to the above effects, the auxiliary member is formed integrally with the flange member, so that the number of parts is small and the assembling work of the photosensitive drum can be easily performed. Further, since the auxiliary member is an elastic body arranged in the recess provided in the flange member, when the contact piece is going to generate self-excited vibration, the elastic body can absorb the vibration. Therefore, the effect of suppressing the generation of abnormal noise can be exhibited more effectively. Further, the sliding contact piece is pressed against a small diameter portion formed on the fixed shaft, and by applying a lubricant to the small diameter portion of the fixed shaft, the fixed shaft holds a lubricant such as grease. Can be maintained satisfactorily, the grease does not spread over time, and the noise suppressing effect can be maintained.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of an image forming apparatus to which the present invention can be applied.

FIG. 2 is an explanatory diagram of a configuration of a photosensitive drum.

FIG. 3 is an explanatory diagram of a structure of a flange member.

FIG. 4 is a front view of the flange member of FIG.

[Explanation of symbols]

1 image forming apparatus, 2 reading unit, 3 recording unit, 4 paper feed tray, 5 pickup roller,
6 paper transport path, 7 transport roller device, 8
Transfer roller, 9 fixing device, 10 recording unit, 1
1 developing device, 12 developing roller, 13 writing device, 14 cleaning device, 15 fixed shaft, 16 small diameter part, 19 device frame,
20 photoconductor drums, 21 photoconductors, 22 ・ 23
Flange member, 24 gear, 25 recess,
26 elastic body, 27 ground plate, 28 contact piece, 29 claw

Claims (4)

[Claims] 1. A photosensitive drum, a flange member fixed to an end portion of the photosensitive drum, a fixed shaft inserted into the flange member to support the photosensitive drum, and a photosensitive member fixed to the flange member. A photoconductor drum having an earth plate for grounding the drum, wherein a sliding contact piece for electrically connecting the photosensitive drum and a fixed shaft is integrally formed on the ground plate, and the sliding contact piece is attached to the shaft. A photosensitive drum, wherein an auxiliary member is arranged so as to be in pressure contact with the fixed shaft so that the sliding contact piece is always in contact with the fixed shaft. 2. The photosensitive drum according to claim 1, wherein the auxiliary member is formed integrally with the flange member. 3. The photosensitive drum according to claim 1, wherein the auxiliary member is an elastic body arranged in a recess provided in the flange member. 4. The photosensitive drum according to claim 1, wherein the sliding contact piece is pressed against a small diameter portion formed on the fixed shaft.