JPH0527613A - Transfer device - Google Patents

Abstract

PURPOSE:To prevent toner from sticking to the paper nonpassing part of a transfer sheet used roller with simple structure by providing the transfer rollers having length corresponding to the minimum width of a transfer and length less than that, and adjusting a position according to the width of the transfer sheet. CONSTITUTION:A transfer device 50 has three transfer rollers 51-53, and each roller has the length L corresponding to the minimum width W1 of the transfer sheet used S. The transfer roller 51 of the most upstream side is rotatively supported at a fixed position where the transfer sheet S passes, by a shaft 511, and the other rollers 52 and 53 can be horizontally moved in parallel with the roller 51 by a driving device. In other words, when the transfer sheet S1 of the minimum width W1 is used, the rollers 52 and 53 are arranged in a direction where a paper passes, so as to superimpose with the roller 51. On the other hand, when a transfer sheet S2 having the width W wider than the minimum width is used, the rollers 52 and 53 are horizontally moved by a necessary amount so that the entire width of the transfer rollers 51-53 corresponds to the width W2 of the transfer sheet S2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for transferring a toner image on a toner image carrier to a transfer material in an image forming apparatus such as a copying machine or a printer.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine or a printer, a toner image formed on a toner image carrier such as a photoconductor is transferred onto a transfer material by a transfer device. Transfer devices that have been proposed and put into practical use include a corona transfer system and a roller transfer system. Recently, the transfer roller method has been reconsidered in terms of lowering ozone and reducing transfer deviation.

FIG. 5 is an explanatory view of an example of an electrophotographic copying machine using a conventional transfer roller. In this copying machine, the photoconductor 1 is charged by the charging roller 2 and exposed by the exposure unit 3 by an optical system (not shown) to form an electrostatic latent image. This latent image is developed by the developing unit 4. On the other hand, the transfer sheet S sent out from the sheet feeding cassette 9 by the action of the separating roller 10 and the separating plate 11 reaches the timing roller 12, from which it is sent to the transfer section in synchronization with the toner image on the photoconductor, and thus, The toner image is transferred onto the transfer paper S by the transfer roller 5. At this time, a bias having a polarity opposite to that of the toner is applied to the transfer roller 5. The transfer paper S is separated from the photoconductor 1 by its own strength, is discharged by the discharging needle 6, is guided by the guide 13, and the toner image is fixed by the fixing device 15. Is discharged to. The photoconductor 1 is cleaned of residual toner by the cleaner 7, erased of residual charges by the eraser 8, and repeats the same process again.

[0004]

In this case, since the transfer roller 5 is always in contact with the photosensitive member 1, when a small size transfer paper having a small paper width is used, the non-sheet passing portion of the transfer roller is used. The developed toner or fog toner on the photoconductor 1 adheres to. If the toner adheres to the transfer roller in this manner, the transfer efficiency may be reduced or the back side of the next transfer paper may be soiled.

In order to solve this problem, Japanese Patent Laid-Open No. 48-4
As disclosed in Japanese Patent No. 0442, it is possible to prepare several kinds of transfer rollers according to the width of the transfer paper and use one of the transfer rollers depending on the size of the transfer paper. There is a problem that the transfer device becomes large and complicated, and the cost becomes high. In addition, the actual exploitation 55-19
As disclosed in Japanese Patent Publication No. 946, when one transfer roller is allowed to move laterally in the axial direction and a transfer paper having a width smaller than the axial length of the photosensitive drum is used, one side edge of the paper is used. It is also proposed that the transfer roller be aligned with one end of the photosensitive drum, and the transfer roller is moved so that the transfer roller faces the photosensitive drum only in the range where the transfer paper exists. However, this transfer device has a problem that it requires a large space for lateral movement of the transfer roller.

Therefore, the present invention is a transfer device having a transfer roller for transferring a toner image formed on a toner image carrier to a transfer material in an image forming device, and developing toner on the toner image carrier is A simple structure that can prevent fogging toner from adhering to the non-sheet passing portion of the transfer roller.
An object is to provide a transfer device that requires a small installation space.

[0007]

According to the above object, the present invention provides a transfer material used in a transfer device having a transfer roller for transferring a toner image formed on a toner image carrier to a transfer material in an image forming apparatus. A plurality of transfer rollers including a transfer roller having a length corresponding to the minimum width and a transfer roller having a length shorter than the minimum width are provided, and at least one of the transfer rollers is laterally moved depending on the width of the transfer material to be used. (EN) Provided is a transfer device which is characterized in that it can be moved and its position can be adjusted.

[0008]

According to the transfer device of the present invention, when the transfer material to be used has the minimum width, the transfer rollers are arranged so as to overlap each other when viewed from the sheet passing direction, and have a width wider than the minimum width. At least 1 when using the transfer material
The book transfer roller is moved laterally so as to obtain a transfer roller width corresponding to the width of the transfer material as a whole,
The position is adjusted.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic structure of a main part of a copying machine adopting an embodiment, and FIG. 2 is a plan view of a transfer roller of a transfer device.
FIG. 3 shows a transfer roller driving device. The copying machine shown in FIG. 1 has substantially the same structure as the copying machine shown in FIG. 5 except for the transfer device, and has a photosensitive drum 1 around which a charging roller 2, a developing device 4 and a timing device are provided. Roller 12,
The transfer device 50, the charge elimination needle 6, the cleaner 7, and the eraser 8 are sequentially arranged. Although not shown in FIG. 1, there is a paper feeding unit including the paper feeding tray 9 on the left side of the timing roller 12, and the fixing device 14 shown in FIG. 5 on the right side of the guide 13 adjacent to the transfer device 50. is there.

The transfer device 50 comprises three transfer rollers 51, 5
2 and 53, each roller has a length (length in the roller axis direction) L corresponding to the minimum width W1 (see FIG. 2A) of the transfer paper S to be used. This length L is necessary and sufficient for transferring the toner image onto the transfer paper S1 having the minimum width. The most upstream transfer roller 51 is rotatably supported by a shaft 511 at a fixed position. This fixed position corresponds to the position where the minimum width transfer sheet passes.

The other rollers 52 and 53 can be laterally moved in parallel with the roller 51 by a driving device 54 shown in FIG. The drive device 54 includes a shaft 55 parallel to the roller 51, a slider 56 slidable along the shaft 55, and a slider 56.
A wire 59 wound around the pulleys 57 and 58, and a motor 6 for rotating and driving one pulley 57.
0, the transfer roller 52 (53) is a slider 5
6 is rotatably fitted.

By rotating the motor 60 forward or backward,
The wire rotates in the forward or reverse direction, whereby the slider 56 moves laterally while the transfer roller 52 (53) is mounted, and the roller 52 (53) can be arranged at a desired position. The operation of the motor 60 is controlled by the control unit 100 including a microcomputer. The control unit 100 also controls the operation of the entire copying machine.

According to the copying machine described above, the photoconductor 1
Is charged by the charging roller 2 and exposed by the exposure unit 3 by an optical system (not shown) to form an electrostatic latent image. This electrostatic latent image is developed by the developing device 4 and becomes a toner image. This toner image is transferred from the device 50 onto the transfer paper S sent from the timing roller 12 in synchronization with this. At this time, a transfer bias is applied to the transfer roller by a power source (not shown). In addition, the transfer rollers 51, 5
2, 53 are rotated by the rotation of the photoconductor 1.

After the transfer, the transfer sheet S is separated from the photoconductor 1 by the rigidity of the transfer sheet itself, is neutralized by the static elimination needle 6, and is then fixed with a toner image by a fixing device (not shown). It is discharged to the outside of the device. On the other hand, the photoconductor 1
The cleaner 7 removes the residual toner, and the eraser 8 erases the residual charge, and the same process is repeated again.

The arrangement of the transfer rollers 51, 52, 53 in the transfer device 50 in the transfer step during the above process is as follows. That is, when the transfer sheet S1 having the minimum width W1 is used, as shown in FIG.
53 is arranged so as to overlap the roller 51 when viewed in the sheet passing direction. When the transfer sheet S2 having a width W2 wider than the minimum width is used, as shown in FIG.
2, 53 are laterally moved by a required amount, the width of the entire transfer roller is made to correspond to the width of the transfer sheet S2, and a portion that cannot be transferred by the roller 51 alone is supplemented.

Thus, none of the transfer rollers comes into contact with the non-image portion of the photoconductor 1, and therefore the transfer rollers 51 to 5 are provided.
3 is not dirty. The control unit 100 (see FIG. 3) executes a transfer roller moving subroutine shown in FIG. 4 in the transfer process. That is, in step S10, it is determined whether or not copying is in progress. If copying is not in progress, the process directly returns to the main routine. If copying is in progress, in step S20 it is determined whether or not the transfer paper size has been changed. If it is "NO", return to the main routine,
If "YES", in step S30, the transfer roller movement amount is calculated based on the current paper size and the changed paper size. Next, in step S40, the motor 60 is operated to laterally move the rollers 52 and / or 53 by a predetermined amount based on the calculation result.

The transfer device described above can be manufactured in a small size so that the transfer roller does not extend beyond the width of the photoconductor 1 and can be easily manufactured. The transfer rollers 52 and 53 may be shorter than the roller 51 as long as the transfer rollers 52 and 53 have a size capable of transferring a toner image to a transfer paper having the maximum width by lateral movement.

The transfer rollers 51, 52 and 53 are
By allowing the photoconductor 1 to come into contact with the photoconductor 1 only at the time of transfer and separating the photoconductor 1 from the photoconductor 1 at other times, contamination of the transfer roller can be prevented more reliably.

[0019]

As described above, according to the present invention, there is provided a transfer device having a transfer roller for transferring the toner image formed on the toner image carrier to the transfer material in the image forming device, the toner image carrier It is possible to provide a transfer device having a simple structure capable of preventing the above developed toner or fog toner from adhering to the non-sheet passing portion of the transfer roller and requiring a small installation space.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a main part of a copying machine adopting an embodiment of the present invention.

2A and 2B are plan views of a transfer roller in a transfer device, where FIG. 2A is a plan view showing a layout corresponding to a minimum width transfer paper, and FIG. 2B is a layout corresponding to a transfer paper wider than the minimum width transfer paper. It is a top view.

3A and 3B show a transfer roller driving device, FIG. 3A is a front view thereof, and FIG. 3B is a bottom view thereof.

FIG. 4 is a flowchart showing a transfer roller movement routine in the operation of the control unit.

FIG. 5 is an explanatory diagram of a conventional example.

[Explanation of symbols]

 50 Transfer Device 51, 52, 53 Transfer Roller 54 Transfer Roller Drive Device 100 Control Unit of Drive Device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Yoshinobu Hara, 2-3-13 Azuchi-cho, Chuo-ku, Osaka City Osaka International Building Minolta Camera Co., Ltd. (72) Daisuke Nagao 2-chome, Azuchi-cho, Chuo-ku, Osaka No. 13 in Osaka Kokusai Building Minolta Camera Co., Ltd. (72) Inventor Junichi Tamaki 2-3-3 Azuchi-cho, Chuo-ku, Osaka City Osaka Kokusai Building Minolta Camera Co., Ltd.

Claims (1)

Claim: What is claimed is: 1. A transfer device having a transfer roller for transferring a toner image formed on a toner image carrier to a transfer material in an image forming apparatus, wherein the transfer material has a minimum width. A plurality of transfer rollers including a transfer roller having a corresponding length and a transfer roller having a length shorter than that, and at least one of the transfer rollers is moved laterally according to the width of the transfer material to be used; A transfer device characterized by being adjustable.