JPH1097145A - Turning part supporting device for image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make one turning member driven by maintaining a space between the peripheral surfaces of two turning members constant and also rotating and driving the other turning member by providing an abutting surface abutting on the other peripheral surface of a photosensitive drum and a transfer roller and energizing the rotary shafts of the photosensitive drum and the transfer roller in a relatively proximate direction. SOLUTION: The rotary shaft 71 of the transfer roller 11 is extended outside at both ends in a length direction, and is supported by shaft receiving members 76. The shaft receiving members 76 are energized by springs 77 in a direction where the transfer roller 11 is made in the proximity of the side of the photoreceptive drum 5. Thus, the rotary shaft 71 is energized on the side of the drum 5 by the spring 77, and the peripheral surface of a space holding member 72 abuts on the peripheral surface of the abutting part 75 of the drum 5. Then, gears 78 and 79 are engaged with each other. Thus, the roller 11 is driven and is rotated in accordance with the rotating and driving of the drum 5, and both peripheral surfaces are maintained by having a constant space.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a rotating unit supporting device for an image forming apparatus.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine, a printer or a facsimile machine, an electrostatic latent image based on image data is formed on a photosensitive drum by a laser scanning unit, for example. Around the photosensitive drum, a developing unit and a transfer roller are provided adjacent to each other. The electrostatic latent image formed on the surface of the photosensitive drum is visualized as a toner image by a developing roller provided in a developing unit. The transfer roller is arranged so that its peripheral surface has a gap corresponding to one sheet of paper to the peripheral surface of the photosensitive drum. Further, the transfer roller is charged with a polarity opposite to that of the toner on the photosensitive drum, and the toner on the peripheral surface of the photosensitive drum is attracted from the back surface of the paper onto the paper supplied to the gap between the photosensitive drum and the transfer roller. To transfer the toner image.

Some of such transfer rollers rotate following the rotation of the photosensitive drum. For example,
It is conceivable that the rotating shaft of the photosensitive drum and the rotating shaft of the transfer roller are connected via a plurality of gears, and the transfer roller is rotated in conjunction with the rotation drive of the photosensitive drum.

[0004]

The above-described image forming apparatus requires a connecting mechanism such as a gear for connecting the respective rotating shafts of the photosensitive drum and the transfer roller, and there is a limit to downsizing. . Also, it is difficult to maintain a constant gap between the peripheral surface of the photosensitive drum and the peripheral surface of the transfer roller.

For this reason, as disclosed in JP-A-58-50563 and JP-A-63-186282, elastic members having a large friction coefficient contacting the peripheral surface of the photosensitive drum at both ends in the length direction of the transfer roller. It is conceivable to provide members. In this case, the rotating shaft of the photosensitive drum and the rotating shaft of the transfer roller are urged in directions approaching each other, whereby the elastic member is elastically deformed and comes into close contact with the peripheral surface of the photosensitive drum. Therefore, if the photosensitive drum is driven to rotate, the transfer roller rotates in conjunction with the elastic member that is in contact with the peripheral surface of the photosensitive drum.

However, since the elastic member provided on the transfer roller is elastically deformed by the urging force applied to each rotating shaft, it is difficult to maintain a constant gap between the peripheral surface of the photosensitive drum and the peripheral surface of the transfer roller. is there. For this reason, it is necessary to make the urging force applied between the rotating shafts constant, and this adjustment work becomes complicated. SUMMARY OF THE INVENTION It is an object of the present invention to provide a rotating section of an image forming apparatus in which a gap between the peripheral surfaces of two rotating members is kept constant and one of the rotating members is driven to rotate so that the other rotating member is driven. It is to provide a support device.

[0007]

According to a first aspect of the present invention, there is provided a rotating portion supporting apparatus for an image forming apparatus, comprising: a first rotating member, a second rotating member, a gap holding member, a pair of gears, Power means. The first rotating member is driven to rotate. The second rotating member rotates following the first rotating member while the peripheral surface of the second rotating member is maintained at a predetermined distance from the peripheral surface of the first rotating member. The gap holding member turns integrally with one of the first turning member and the second turning member, and closes a gap between the peripheral surface of the first turning member and the peripheral surface of the second turning member. In order to maintain the constant, a contact surface that contacts the other peripheral surface of the first rotating member and the second rotating member is provided. The pair of gears rotate integrally with the first rotating member and the second rotating member, respectively, and mesh with each other to transmit a rotational driving force. The urging means urges the rotation axes of the first rotating member and the second rotating member in a direction relatively approaching.

[0008] Thus, the gears mesh with the peripheral surface of the first rotating member and the peripheral surface of the second rotating member maintained at a predetermined distance, and the rotational driving force can be transmitted. As a first rotating member, a photosensitive drum on which a toner image is formed on the peripheral surface is used, and as a second rotating member, a toner image on the peripheral surface of the photosensitive drum is supplied to a gap between the peripheral surface of the photosensitive drum. A transfer roller that transfers the image to the recording medium can be employed. In this case, the gap between the photosensitive drum and the transfer roller is maintained constant, and the transfer roller can be rotated in conjunction with the photosensitive drum by driving the photosensitive drum to rotate.

The gap holding member can be configured to rotate integrally with the rotation shaft of the transfer roller. At this time, the gap between the photosensitive drum and the transfer roller can be maintained constant by setting the gap holding member to a diameter larger than the diameter of the transfer roller by a predetermined value. The photoreceptor drum has a photoreceptor having a photoreceptor layer formed on a peripheral surface thereof, a contact portion in which a gap holding member is in contact with both ends in the length direction of the photoreceptor, and a meshing portion in which one of gears is formed. It can be.
In this case, while the gap holding member provided integrally with the transfer roller is in contact with the contact portion, the rotation can be performed while maintaining the gap between the two peripheral surfaces constant.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A printer employing an embodiment according to the present invention will be described with reference to the drawings. [Overall Configuration] In FIG. 1, a printer main body 1 has an upper casing 2 and a lower casing 3. On the upper surface of the upper casing 2, a paper feed tray 4 on which paper is placed is attached. The printer main body 1 is provided with an image forming unit 6 including a photosensitive drum 5. Image forming unit 6
Is provided with a transfer roller 11 adjacent to the photosensitive drum 5. The image forming section 6 is provided with a developing unit 8 including a developing roller 7 adjacent to the photosensitive drum 5. A laser scan unit 10 that forms an electrostatic latent image on the surface of the photosensitive drum 5 is provided below the image forming unit 6.

Between the paper feed tray 4 and the image forming section 6, a paper transport path 12 for guiding paper between the photosensitive drum 5 and the transfer roller 11 is formed. Paper transport path 1
2, a paper feed roller 13 for feeding paper in the transport direction;
In order to prevent double feeding, a paper feed pad 14 which is pressed against the paper feed roller 13 is provided. A fixing device 15 for heating and fixing the toner image transferred onto the sheet is provided downstream of the image forming unit 6 in the sheet conveying direction. Further downstream of the fixing device 15 is provided a discharge roller 16 for discharging a sheet having an image formed on its surface to the outside.

[Developing Unit] The developing unit 8 is shown in FIG.
As shown in FIG. 1, a developer storage chamber 17 for storing the developer and a developer supply chamber 18 in which the developing roller 7 is mounted are provided. The developer storage chamber 17 is provided with a stirring member 19 having at least one end protruding outside the developer storage chamber 17 and rotatably supported. The stirring member 19 includes the rotating shaft 2
0 and an agitator 21 protruding around the rotation shaft 20. One end of the rotation shaft 20 of the stirring member 19 protrudes outside the developer storage chamber 17 and is driven to rotate by a driving unit (not shown).

In the developer supply chamber 18, the developing roller 7 and the supply roller 22 are rotatably supported. The developing roller 7 contacts the photosensitive drum 5 and forms a toner image on the photosensitive drum 5. The supply roller 22
The developer supplied from the developer storage chamber 17 is supplied to the developing roller 7. The supply roller 22 is formed to have a larger width in the length direction than the developing roller 7. The developing roller 7 and the supply roller 22 are driven to rotate by driving means (not shown).

In the developing unit 8, a developer is stored in a developer storage chamber 17 at a manufacturing stage. As the developer, for example, a one-component type toner alone or a two-component type start developer is stored. When the developing unit 8 is arranged at a predetermined position of the printer main body 1 and starts image formation,
The rotation shaft 20 of the stirring member 19 is rotated to stir the developer stored in the developer storage chamber 17.

[Image Forming Section] As shown in FIG. 3, the image forming section 6 includes a developing unit 8 and a photosensitive drum unit 35.
And As shown in FIG. 2, the developing unit 8 has a developer storage chamber 17 for storing a developer and a developer supply chamber 18, and the developer supply chamber 18 includes a developing roller 7 and a supply roller. 22 are rotatably supported.
A gear 36 is attached to the rotation shaft of the supply roller 22. The gear 36 is engaged with a drive gear 37 provided on the printer main body 1 side. A gear 36a having the same diameter as the gear 36 is attached to the rotation shaft of the gear 36.
The gear 36a meshes with the idle gear 38. The idle gear 38 is composed of two gears having different diameters. One of the two gears meshes with the gear 36a, and the other meshes with the gear 39 attached to the rotating shaft of the developing roller 7. Further, the gear 36 a meshes with a gear 40 attached to the rotation shaft 20 of the stirring member 19. Below the developing unit 8, a shaft attaching portion 41 connected to the photosensitive drum unit 35 is provided.

The photosensitive drum unit 35 has a support frame 42 for rotatably supporting the photosensitive drum 5 and the transfer roller 11. The support frame 42 includes an arm 43 and an arm 4 extending in the direction of the shaft attachment 41 of the developing unit 8.
3 and a drum support 44 extending upward. The distal end of the arm 43 on the side of the developing unit 8 has a support 48 that supports the shaft attachment 41 of the developing unit 8. The developing unit 8 and the photosensitive drum unit 35
The photosensitive drum 5 and the developing roller 7 are connected by a spring 50 so as to be rotatable about a shaft attaching portion 41 and a support portion 48.
Are urged in the direction in which they come into contact with

The photosensitive drum 5 is made of metal-free phthalocyanine (charge generating material) 5 parts by weight N, N'-bis (O, P-dimethylphenyl) N, N'-diphenylbenzidine (hole transporting material) 40 Parts by weight 3,3 ', 5,5'-tetraphenyldiphenoquinone (electron transporting material) 40 parts by weight Polycarbonate (binder resin) 100 parts by weight Dichloromethane (solvent) 800 parts by weight The prepared coating solution is applied onto an aluminum drum tube having a diameter of 16 mm by dip coating, followed by hot-air drying at 60 ° C. for 60 minutes to form a 30 μm-thick single-layer dispersed organic photoreceptor. Further, the developing roller 7 has a diameter of 12 mm and is made of a synthetic resin column.

The photosensitive drum 5 is driven to rotate in a direction indicated by an arrow A in FIG. Developing roller 7
Is rotationally driven in the direction of arrow B in FIG. Therefore, the photosensitive drum 5 and the developing roller 7 are driven to rotate in the same direction in a state where the surfaces are in contact with each other. As a result, the contact surface is driven to rotate with friction.

[Transfer Roller] As shown in FIG. 4, the transfer roller 11 is mounted on a rotating shaft 71 and is rotatable adjacent to the photosensitive drum 5. Gap holding members 72 are attached to both ends of the rotation shaft 71 in the length direction. The gap holding member 72 is made of POM, PC, P
It is made of a hard synthetic resin having excellent abrasion resistance and heat resistance such as BT, and is one paper (for example, 0.1 mm) more than the transfer roller 11.
3 mm) A roller having a large radius.

The photosensitive drum 5 includes a photosensitive section 74 in which a photosensitive layer is formed on a drum tube made of aluminum or the like, and a photosensitive section 7.
The photoconductor layer is omitted at both ends in the length direction of the drum 4 and the abutting portions 75 are exposed to expose the drum tube. The gap holding member 72 on the transfer roller 11 side and the contact portion 75 of the photosensitive drum 5 are provided so as to face each other at both ends in the length direction.

A pair of gears 78 and 79 meshing with each other are provided on the rotating shaft 71 of the transfer roller 11 and one end of the photosensitive drum 5 in the longitudinal direction. One of the gears 78 is provided integrally with one end of the photosensitive drum 5. Further, the other gear 79 is connected to one of the gap holding members 7.
It is attached to the outer side in the longitudinal direction of the second shaft 2 so as to rotate integrally with the rotating shaft 71. The gears 78, 79 are configured such that the peripheral surfaces of the gap holding members 72, 72 are in contact with the contact portions 75 of the
When they are in contact with each other, they are configured to engage with a slight gap left.

The rotation shaft 71 of the transfer roller 11 extends outward at both ends in the length direction,
6 supported. The bearing member 76 is urged by a spring 77 in a direction in which the transfer roller 11 approaches the photosensitive drum 5 side. Therefore, the rotating shaft 71 is urged toward the photosensitive drum 5 by the spring 77, and the peripheral surface of the gap holding member 72 contacts the peripheral surface of the contact portion 75 of the photosensitive drum 5. At this time, the gears 78 and 79 mesh with each other. Since the gap holding member 72 is made of a hard synthetic resin, the gap between the peripheral surface of the transfer roller 11 and the peripheral surface of the photosensitive drum 5 can be set to the difference between the radius of the transfer roller 11 and the radius of the gap holding member 72, Here, for one sheet of paper (0.3 mm)
Can be maintained. Also, a pair of gears 78, 79
Are in mesh with each other, and the rotational driving force can be transmitted to the transfer roller 11 by rotating the photosensitive drum 5.

From the above, the transfer roller 11 is reliably rotated in conjunction with the rotation of the photosensitive drum 5, and
The gap between the peripheral surface of the photosensitive drum 5 and the peripheral surface of the transfer roller 11 can be kept constant. The above-described configuration in which the transfer roller 11 is driven by the photosensitive drum 5 can also be applied to a charging roller, a cleaning brush, and the like provided adjacent to the photosensitive drum.

[Other Embodiments] The gap between the peripheral surface of the transfer roller 11 and the peripheral surface of the photosensitive drum 5 may be equal to or more than one sheet (0.3 mm or more).

[0025]

According to the present invention, the rotating portion supporting device of the image forming apparatus can rotate the second rotating member following the rotation of the first rotating member. The peripheral surface can be maintained with a constant gap.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a schematic configuration of a printer to which an embodiment of the present invention is applied.

FIG. 2 is a longitudinal sectional view illustrating a schematic configuration of a developing unit.

FIG. 3 is a schematic configuration diagram of an image forming unit.

FIG. 4 is an explanatory diagram showing a relationship between a photosensitive drum and a transfer roller.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printer main body 5 Photoconductor drum 11 Transfer roller 71 Rotation shaft 72 Gap holding member 74 Photosensitive part 75 Contact part 76 Bearing member 77 Spring 78 Gear 79 Gear

Claims (5)

[Claims] A first rotating member that is driven to rotate, and a first rotating member that rotates following the first rotating member while a peripheral surface of the first rotating member is maintained at a predetermined distance from a peripheral surface of the first rotating member. A second rotating member, which is integrally rotated with one of the first rotating member and the second rotating member, and a peripheral surface of the first rotating member and a peripheral surface of the second rotating member. A gap holding member having an abutting surface that abuts on the other peripheral surface of the first rotating member and the second rotating member, in order to maintain a constant gap between the first rotating member and the second rotating member. A pair of gears that rotate integrally with the second rotating member and mesh with each other to transmit a rotational driving force; and a direction in which the rotating shafts of the first rotating member and the second rotating member are relatively close to each other. And a biasing means for biasing the rotating portion of the image forming apparatus. 2. The image forming apparatus according to claim 1, wherein the first rotating member is a photosensitive drum on which a toner image is formed on a peripheral surface, and the second rotating member is a photosensitive drum on the peripheral surface of the photosensitive drum. The rotating portion support device of the image forming apparatus according to claim 1, wherein the transfer portion support device is a transfer roller that transfers a sheet to a sheet supplied to a gap between the surface and the sheet. 3. The rotating section support device of the image forming apparatus according to claim 2, wherein the gap holding member rotates integrally with a rotation shaft of the transfer roller. 4. The rotating portion support device of an image forming apparatus according to claim 2, wherein said gap holding member has a diameter larger by a predetermined value than a diameter of said transfer roller. 5. The photosensitive drum includes a photosensitive portion having a photosensitive layer formed on a peripheral surface thereof, a contact portion in which the gap holding member contacts both ends in a length direction of the photosensitive portion, and one of the gears. The rotating portion support device for an image forming apparatus according to claim 2, further comprising: a meshing portion formed with a rotating member.