JPS6371876A - Cleaning device for transfer belt - Google Patents

Abstract

PURPOSE:To prevent the occurrence of color deviation by abutting a cleaning blade to a transfer belt after each color is reciplocatingly transferred and isorating said blade from the belt at the time of transfer. CONSTITUTION:The cleaning blade 40 is fitted to a turnable shaft 41 on the side of discharging a transfer sheet, and normally energized in the direction in which a spring 45 isorates it from the transfer belt 45. A solenoid 44 is linked to the arm lever 43 of the shaft 41. In order to copy plural colors, the transfer belt 1 is rotated normally and reversely three times. After the reciplocating transfer, the solenoid 44 is excited to attract the arm lever 43, and the blade 40 is abutted on the belt 1. Since the belt 1 receives no load from the blade 40 during the transfer, no slip occurs, and the color deviation due to slip can be prevented accordingly.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Back of Scallops The present invention relates to a cleaning device for a transfer belt.

FIG. 1 shows a perspective view of an example of a color image forming apparatus.

In the figure, an endless transfer belt 1 is stretched around a driving roller 2 and a driven roller 3 in one direction. The transfer paper S is fed in the direction of the arrow by a paper feed roller 4, electrostatically attracted to the transfer belt 1, and conveyed on the belt.

The document table 5 is provided parallel to the direction in which the transfer belt 1 is disposed, and is driven back and forth in this direction. With respect to a color image of an original (not shown) on the original table 5, this light image is formed onto a photoreceptor belt 8 via a converging light transmitter array 6, a filter 7, etc., and is applied onto the belt. An electrostatic latent image is formed.

This is done for each color separation, and the electrostatic latent image corresponding to each color is T
Color toner developing sleeves 9A, 98.9C of fl image device 9
By switching the positions of the sleeves and exposing them to the developing section, the images are developed by these sleeves.

When the transfer paper S is electrostatically attracted to the transfer belt 1, carried by the transfer belt, and passed through the transfer section 110, the first developed image on the photoreceptor belt 8 is transferred by the transfer charger 12. transferred to paper.

At the time of this transfer, the transfer belt 1 is driven in the direction of the arrow A, whereas the document table 5 is moved forward in the direction opposite to the direction of the arrow A, and after this forward IPIItt is completed, the document table 5 is moved backward. At this time, that is, after the trailing edge of the transfer paper passes through the transfer section 11, the transfer belt 1 is reversed, and the upper belt portion moves in the opposite direction to the direction of the arrow, in preparation for the next transfer. Note that when the transfer belt 1 is reversed, the driven roller 3 is slightly lowered, and the contact between the toner image on the transfer paper and the photoreceptor belt 8 is broken.

Next, by reciprocating the same process, the second developed image and the third developed image are transferred onto a sheet of transfer paper one on top of the other so that no positional deviation occurs.

After the final transfer, the transfer paper passes between the static elimination chargers 13 and advances to the transfer paper fixing system 14, which is provided in the transfer paper ejection direction and consists of a pair of rollers.

After being fixed in this area, it is ejected outside the machine.
Note that in the copying machine of this example, the original table of the image forming system consisting of the document table 5, the convergent light transmitting member play 6, etc. is of a type that moves back and forth.

A rack 17 is fixed to one end of the document table 5, and is engaged with a pinion 16 directly connected to a motor 15.

When the motor 15 of these rotates in the forward and reverse directions, the pinion 16. The document table 5 is driven back and forth through the rack 17''1.The wire 18, which is fixed at one end to the document table 5, is hooked and rotated by the idle pulley 19 and the pulley 20 of the drive roller 2, and is locked to one end of the spring 22.

When the motor 15 rotates forward and reverse, and the document table 5 is driven back and forth,
The pulley 20 is rotated via the wire 18, and the transfer belt 1
is rotated in forward and reverse directions in synchronization with the movement of the document table 5. In addition, the first l on pulley 20! An mvJ type clutch 23 is connected.

Lower fixing roller 1 constituting one of the transfer paper fixing systems 14
4a is driven by the driving force of the motor 25 via gears 26 and 27. A gear 28 is provided at one end of the fixing roller 14a.
is fixedly installed, and the rotation of this gear 28 is transmitted via an idle gear 29 to a gear 31 fixed to the drive roller 2. Note that a second drive system clutch 24 is connected to the gear 31.

At the time of transfer, the first drive system clutch 23 is in an on state, whereas the second drive system clutch 24 is in an off state.

Therefore, the transfer belt 1 is driven by a drive system from the motor 15, and in this case, it is rotated forward and backward in synchronization with the movement of the document table 5, thereby determining the relative position between the document and the transfer paper. There will be no misalignment.

Next, when the final transfer of RL is completed, the first drive system clutch 23 is turned off and the second drive system clutch 24 is turned on. Therefore, the transfer belt 1 is driven by the drive system from the motor 25 in synchronization with the fixing speed.

Incidentally, in this type of image forming apparatus, a cleaning member is brought into contact with and separated from the transfer belt l shown in FIG. 1, and the surface of the transfer belt is cleaned when the cleaning member comes into contact with the transfer belt l.

On the other hand, in this type of transfer belt drive system, the drive roller 2 has a relatively small diameter and the relative contact area between the belt and the roller is small, so even if a small load is applied to the belt, the drive roller 2 has a relatively small diameter. It is easy to cause slip between the roller and the roller, and if such slip occurs, the alignment of the color image will be misaligned, resulting in color misregistration.

In view of this situation, if the cleaning member is brought into contact with the transfer belt needlessly without considering any timing, if this contact timing is applied during transfer, it will become a load and cause color misalignment. etc. will occur.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, it is an object of the present invention to enable cleaning of a transfer belt without causing misalignment of color images.

In order to achieve the above object, the present invention forms developed images using toners of different colors on each photoreceptor.

In an image forming apparatus, the developed toner images of each color are sequentially transferred onto a sheet of transfer paper carried by a transfer belt, one layer at a time, while rotating the transfer belt in forward and reverse directions.

After completing multiple transfers, it is placed in the cleaning position,
The present invention is characterized in that a cleaning member for the transfer belt is provided at a distance from the transfer belt at the time of transfer.

The present invention will be explained below based on one embodiment.

In FIG. 2, reference numeral 40 indicates a cleaning blade 1±, which is an example of a cleaning member. This cleaning blade 40 is
It is located at the bottom of the transfer paper ejection side. The cleaning blade 40 is made of a material such as phosphor bronze, and has a tip 40a made of polyurethane at its tip. In addition,
You can do without this chip.

A shaft 41 that fixes the base end of the cleaning blade 40 is rotatably supported by a side plate (not shown) of the cleaning unit 42. A base of an arm rod 43 is fixed to the shaft 41, and a rod 44a of a solenoid 44 is connected to its free end. A tension spring 45 is applied to the arm rod 43, and the elasticity of this spring gives the arm rod 43 the tendency to rotate counterclockwise in the figure. In this application state, the tip 40a of the cleaning blade 40 is separated from the transfer belt 1.

Here, as described above, in order to perform color copying, the transfer belt 1 rotates in forward and reverse directions, and the upper belt portion reciprocates a total of three times. During this time, if a slip occurs between the drive roller 2 and the belt 1, color misregistration will occur, thereby increasing the load on the belt that is likely to cause the slip.

It is necessary to avoid applying it during repeated transfers.

Therefore, in this embodiment, when the transfer belt 1 is driven in synchronization with the drive on the transfer paper fixing system 14 side (motor 25 wobbling drive FII), the solenoid 44 is excited and the arm rod 43 is pulled. Jt force direction when .

The cleaning blade 41 is rotated so that the tip 40a of the cleaning blade 41 comes into contact with the transfer belt 1.

Of course, this is the time when multiple transcriptions have been completed;
Even if the belt slips to some extent, it will not have any adverse effect on the alignment of one image.

In this way, the cleaning blade 40 is in contact with the transfer belt during non-transfer and is separated from the belt during transfer, so it is expected that the driving force will be reduced without applying more tension to the belt than necessary. can do.

According to the present invention, it is possible to provide a transfer belt cleaning device that prevents misregistration of color images.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an image forming apparatus which is a temporary example of the present invention, and FIG. 2 is a schematic diagram of an apparatus according to an embodiment of the present invention. 1... Transfer belt 8... Photoreceptor 40...
・Cleaning blade as a cleaning member

Claims (1)

[Claims] 1, in which developed toner images of different colors are formed on photoreceptors, and these toner developed images of each color are carried on a transfer belt.
While rotating the transfer belt forward and backward, the sheets of transfer paper are sequentially transferred.
A transfer belt cleaning device, which is used in an image forming apparatus that performs overlapping transfer, and includes a transfer belt cleaning member that is placed at a cleaning position after completing multiple transfers and is placed at a position separated from the transfer belt during transfer. .