JPH11305574A - Transfer device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily replace the worn bearing of a transfer roller by comprising a transfer roller and a bearing for supporting the transfer roller, and providing the transfer roller in such a manner as to be attachable and detachable relative to a transfer device body with it left supported by the bearing. SOLUTION: A bearing 11 is inserted to the longitudinal end part of a transfer roller 3. The transfer roller 3 is mounted on a transfer unit 5 by holding the bearing 11 by a holder 18. In the state where a process cartridge is removed from an image forming device body, a drum 2 is separated from the transfer roller 3, the transfer roller 3 is moved upward by a pressure spring 21 through the holder 18, and its end part is engagingly held by an arm part 22 to prevent the roller 3 from being slipped out. The transfer roller 3 can be manually pulled out against the elastic force of the arm part 22, and the bearing 11 can be separated from the holder 18 by pulling the transfer roller 3 upward against the elastic force of the arm part 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer device which is preferably used for an image forming apparatus such as an electrophotographic apparatus and transfers an image from an image carrier to a transfer material.

[0002]

2. Description of the Related Art Conventionally, in a transfer section of an image forming apparatus, for example, in a device such as a laser printer having electrophotographic technology, an image forming section is provided as an image carrier in a process cartridge detachably mountable to an image forming apparatus main body. An image is formed on the photosensitive drum using an image forming agent such as a toner. In recent years, in order to transfer an image formed by such a known technique to a transfer material (paper), apparatuses using roller transfer in addition to corona transfer have increased. In such an image forming apparatus using roller transfer, it is necessary to exchange the transfer roller several times during the life of the apparatus main body in order to cope with the high durability of the main body. This is because the life of the transfer roller during roller transfer, such as wear, is shorter than that of the apparatus main body. FIG. 8 is a side view of a transfer section of a conventional image forming apparatus, and replacement of a conventional transfer roller will be described with reference to FIG.

In FIG. 8, reference numeral 101 denotes an image forming process unit, which is a process unit 10 according to a known technique.
A process cartridge 103 for forming a predetermined image on the drum 102 in the printer 1; a process cartridge 103 arranged opposite to the drum 102 for transferring a transfer material (paper) P between the drum 102 and the process cartridge 103;
A transfer roller 104 for transferring an image on a drum 102 formed in the process cartridge 101 onto a sheet P is provided with a rotation center on the axis of the transfer roller 103, and is arranged at a predetermined position. Guide from the pre-transfer process to the nip portion between the drum 102 and the transfer roller 103.
And a transfer unit for holding and fixing the pre-transfer guide 104 and the like. The transfer unit 105 has a transfer unit for guiding an image transferred onto the sheet P to a fixing device for fixing the image onto the sheet P. And the like. Reference numeral 106 denotes a hole provided in the transfer unit 105 for hooking a hook 107 of the pre-transfer guide 104. A is an arrow indicating the direction in which the process cartridge 101 is inserted when the process cartridge 101 is inserted from above the apparatus main body (not shown).

The transfer roller 103 forms a nip between the transfer roller 103 and the drum 102, and is configured so that both ends thereof are held by bearings so that the outer periphery of the transfer roller 103 contacts the drum 102 with an appropriate pressing force. The image on the drum 102 is transferred to the transfer material P while being conveyed. 108 is the transfer roller 10
Reference numeral 109 denotes a pressure spring for pressing the bearing 108 toward the drum 102. The bearing 108 and the pressure spring 109 are used for the transfer roller 10.
3, the transfer roller 103 and the drum 102 are in contact with each other in the longitudinal direction.

In the above configuration, the guide 107 before transfer is removed from the hole 106 of the transfer unit 105 to replace the transfer roller 103, and the transfer guide 104 is further removed.
Is rotated upward about the transfer roller 103, and is transferred from the transfer unit 105 to the pre-transfer guide 104 and the transfer roller 103.
At the same time. Next, the transfer roller 103 can be removed by removing the patching portion (locking portion) from the pre-transfer guide 104. Thereafter, the transfer roller 103 for replacement is inserted into the pre-transfer guide 104 for replacement of the transfer roller, and the transfer roller 103 is attached to the apparatus transfer unit in a procedure reverse to that when the transfer roller 103 is removed.

[0006]

However, the above-mentioned prior art has the following problems.

In the transfer roller 103 described in the above conventional example, a drive gear (not shown) is provided at one end in the longitudinal direction in order to rotationally drive the roller 103. A gear provided at one end meshes with a drive gear to rotate the transfer roller 103. Of the two bearings at both ends for the transfer roller 103, the bearing 108 on the drive gear side is severely worn by the pressure generated by the pressure angle of the gear. Therefore, the bearing 108 has a replaceable configuration.

However, since the bearing 108 is provided on the apparatus main body side, the replacement operation is difficult. Further, at the time of the replacement operation, the operator rolls the small round bearing 108 and the bearing 108 enters the apparatus main body. As a result, there is a possibility that the apparatus body may be damaged.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a transfer device capable of easily replacing a worn bearing.

[0010]

According to the present invention, there is provided a transfer roller for forming a nip between an image carrier and a transfer roller for transferring an image from the image carrier to a transfer material passing through the nip. A transfer roller having a bearing for supporting the transfer roller, wherein the transfer roller is detachable from the transfer device main body while being supported by the bearing.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1, 2, 3, 4, 5, 6, and 7. FIG.

FIG. 1 is a side view showing a transfer section of the image forming apparatus of the present embodiment and the structure before and after the transfer section. In FIG. A process cartridge 2 for forming an image using the photosensitive drum 2 is disposed in the process cartridge, and a photosensitive drum as an image carrier for forming an image by holding a developer such as toner on the outer periphery. A transfer roller (not shown) for transferring a transfer material (paper) P to the drum 2 and transferring an image formed on the drum 2 in the process cartridge 1 onto the paper P, and a transfer roller 3 A pre-transfer guide for guiding the sheet P from the pre-transfer process to the nip portion between the drum 2 and the transfer roller 3 by providing a rotation center on the axis of the Before transfer A transfer unit for holding and fixing the guide 4 and the like, and a guide for guiding an image transferred onto the paper P at the transfer unit to a fixing device for fixing the paper P on the paper P in the transfer unit 5 Is also included. Reference numeral 6 is provided in the transfer unit 5 and includes a pre-transfer guide 4.
Hole for catching the hook 7. Also, A
Is an arrow indicating the direction in which the process cartridge 1 is inserted when the process cartridge 1 is inserted from above the apparatus main body (not shown).

The process cartridge includes a photosensitive drum 2,
A charging device, a developing device, and a cleaning device are provided. After the photosensitive drum 2 is charged by the charger, the photosensitive drum 2 is irradiated with a laser beam according to image information to form an electrostatic latent image. The electrostatic latent image is visualized with toner by a developing device, and after a toner image is formed on the drum 2, the toner image is transferred from the drum 2 to a transfer material by the transfer roller 3. After the image transfer, the toner image on the transfer material is fixed by a fixing device. On the other hand, the residual toner on the photosensitive drum 2 after the transfer is cleaned by the cleaning device. Thereafter, the photosensitive drum 2 is again charged by the charger, and the image forming process as described above can be performed.

The transfer roller 3 includes a core to which a transfer voltage is supplied, and a conductive elastic body such as a sponge that covers the core. A nip portion is formed between the transfer roller 3 and the drum 2. The two ends of the gold are held by bearings so that the outer periphery of the drum 2 is brought into contact with the drum 2 by an appropriate pressing force. FIG. 2 is a plan view of a transfer portion of the present embodiment. The transfer roller 3 has bearings 11 and 12 at both ends 9 and 10 thereof.

FIG. 3 is an enlarged view of the end 9 and the bearing 11.
FIG. 4 is a cross-sectional view taken along the line BB, and FIG. 5 is a side view seen from the direction of arrow C. A bearing 11 is inserted through an end 9 of the transfer roller 3 in the longitudinal direction, and a tip 13 of the end 9 has a D-cut shape as shown in FIG. Reference numeral 14 denotes a drive gear, and the mounting inner diameter 15 has a D shape that matches the D cut shape of the tip 13. Straight part 16 with inner diameter 15
Is provided with a plurality of fine projections 17 integrally,
The drive gear 14 is pressed into the leading end 13 of the transfer roller 3.
The drive gear 14 is meshed with a gear provided at one end of the drum 2 via a drum 2 from a drive motor of an image forming apparatus main body (not shown).
Receives rotational drive.

The bearing 11 is held by the holder 18 so that the transfer roller 3 is attached to the transfer unit 5.
The side surface 19 of the holder 18 is positioned and inserted into the guide rib 20 of the transfer unit 5 and is guided in a direction approaching the drum 2. The holder 18 is urged in the direction of the drum 2 by a pressing spring 21. Thereby, the transfer roller 3 is pressed against the drum 2. When the process cartridge 1 is detached from the image forming apparatus main body, the drum 2 is separated from the transfer roller 3 and the transfer roller 3 is
The upper end 9 is moved upward by the pressure spring 21 via the arm 8 and the end 9 is held by the arm 22 to prevent the roller from coming off. The transfer roller 3 can be pulled out manually against the elastic force of the arm 22, and the transfer roller 3 can be replaced.

FIG. 6 is an enlarged view of the end portion 10 and the bearing 12.
FIG. 7 shows a cross-sectional view taken along the line EE. The end 10 of the transfer roller 3 opposite to the drive side in the longitudinal direction is inserted through a bearing 12, and the bearing 12 is
The transfer roller 3 is pressed against the drum 2 by this. The end 10 of the transfer roller 3 is inserted into the bearing 12 in the direction F in FIG. In a state where the process cartridge 1 is removed, the drum 2 is separated from the transfer roller 3, the bearing 12 and the transfer roller 3 are moved upward by the pressing spring 25, and the upper end surface 26 of the bearing 12 abuts on the stopper 27 and is held. You.

The elastic body of the transfer roller 103 and the drum 102 are in contact with each other in the longitudinal direction by the pressurizing springs 21 and 25. Of the two bearings 11 and 12 at both ends, the bearing 11 on the drive gear 14 side is a gear. To receive the pressure generated from the pressure angle, the pressure spring 21 on the drive gear 14 side is set to have a higher load than the pressure spring 24 on the side opposite to the drive side.

In the above configuration, replacement of the transfer roller 3 and the like will be described below.

For replacement of the transfer roller 3, first, the claw 7 of the pre-transfer guide 4 is removed from the hole 6 of the transfer unit 5. Next, the bearing 11 is removed from the holder 18 by pulling the transfer roller 3 upward against the elastic force of the arm 22. Next, the end 10 of the transfer roller 3 is pulled out in the direction opposite to the direction F in FIG. Further, the pre-transfer guide 4 is rotated upward around the transfer roller 3, and the pre-transfer guide 4, the transfer roller 3 and the bearing 1 are transferred from the transfer unit 5.
1 and the drive gear 14 are simultaneously and integrally removed.

Next, the transfer roller 3 can be removed from the pre-transfer guide 4 against the patch portion (locking portion) 8. Thereafter, the transfer roller 3 for replacement is fitted into the patchon section 8 of the original pre-transfer guide 4, and the transfer roller 3 is attached to the transfer unit 5 in a reverse procedure to the removal procedure.

As described above, the transfer roller 3, the bearing 11, and the drive gear 14 can be simultaneously and integrally exchanged. if,
If only the bearing 11 with severe wear damage is to be replaced,
The press-fitted drive gear 14 may be pulled out, the bearing 11 may be removed, the replacement bearing 14 may be inserted through the end 9, and then the original drive gear 14 may be press-fitted again.

[0023]

As described above, according to the present invention,
The worn bearing of the transfer roller can be easily replaced. Also, particularly, since the pre-transfer guide, the transfer roller, and the bearing are simultaneously and integrally removed from the apparatus main body and then the bearing is replaced, the operator does not accidentally drop the bearing into the apparatus main body, It is possible to prevent the main body of the apparatus from being damaged.

[Brief description of the drawings]

FIG. 1 is a side view illustrating an image transfer unit of an image forming apparatus according to the present invention.

FIG. 2 is a plan view showing an image transfer unit of the image forming apparatus of the present invention.

FIG. 3 is an enlarged plan view showing the vicinity of a bearing of the image forming apparatus of the present invention.

FIG. 4 is a sectional view showing the vicinity of a bearing of the image forming apparatus of the present invention.

FIG. 5 is a side view showing the vicinity of a bearing of the image forming apparatus of the present invention.

FIG. 6 is an enlarged plan view showing the vicinity of a bearing of the image forming apparatus of the present invention.

FIG. 7 is a sectional view showing the vicinity of a bearing of the image forming apparatus of the present invention.

FIG. 8 is a side view showing an image transfer unit of a conventional image forming apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Process cartridge 2 Drum 3 Transfer roller 4 Pre-transfer guide 5 Transfer unit 6 Hole 7 Claw 8 Patchon part 9 End part 10 End part 11 Bearing 12 Bearing 13 Front end 14 Drive gear 15 Inner diameter 16 Linear part 17 Projection 18 Holder 19 Side surface 20 Guide rib DESCRIPTION OF SYMBOLS 21 Pressing spring 22 Arm part 23 Side surface 24 Guide rib 25 Pressing spring 26 Upper end surface 27 Stopper

Claims (3)

[Claims] 1. A transfer roller for forming a nip portion between an image carrier and a transfer roller for transferring an image from the image carrier to a transfer material passing through the nip portion, and a bearing for supporting the transfer roller. Wherein the transfer roller is detachably attached to the transfer device main body while being supported by the bearing. 2. The transfer device according to claim 1, wherein the transfer roller is driven to rotate from one end in a rotation axis direction, and the bearing is provided at the one end. 3. The transfer roller is provided at one end thereof with a drive gear for driving the transfer roller to rotate, and the transfer roller is attached to and detached from the transfer device main body while the drive gear is provided. 3. The transfer device according to claim 2, wherein the transfer device can be used.