JPH0617129Y2 - Transfer belt drive - Google Patents

Description

TECHNICAL FIELD The present invention relates to a transfer belt driving device applied to a copying machine or the like.

(Prior Art) As a copying machine using a transfer belt, for example, a color copying machine is known. This color copying machine is one in which visible images of different colors on a photoconductor are successively transferred onto one sheet of transfer paper on a transfer belt, and after the final transfer, the transfer paper is fixed by a fixing system. Is. Conventionally, in a belt driving device that drives this type of transfer belt, a configuration has been adopted in which the traveling speed of the transfer belt and the rotation speed of the fixing system are determined according to their respective functions. However, due to the effect of the speed difference, there is a problem that the transfer paper is loosened between the transfer belt and the fixing system to cause image rubbing.

(Purpose) An object of the present invention is to provide a transfer belt driving device capable of solving the above problems.

(Structure) In order to achieve the above-mentioned object, the present invention comprises an endless transfer belt which is stretched in one direction and allows a transfer paper to pass through a transfer section.
An original table moving means for moving the original table in the arrangement direction of the transfer belt, a transfer sheet fixing system for fixing the transfer sheet provided in the transfer belt discharge direction with respect to the transfer belt, and the original table moving means. A moving means drive system for driving, a fixing drive system for rotationally driving the transfer paper fixing system, and a driving force from the moving means drive system are transmitted to the transfer belt to synchronize the transfer belt with the document table moving means. And a first rotation transmission system for driving the transfer belt, and a second rotation for transmitting the driving force from the fixing drive system to the transfer belt to drive the transfer belt in synchronization with the fixing drive system. And a transmission system for transmitting rotation to the first rotation transmission system during transfer and to the second rotation transmission during fixing.
It is characterized by switching to each rotation transmission system.

Hereinafter, the present invention will be described based on an embodiment.

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 sent in the direction of the arrow by the paper feed roller 4, electrostatically attracted to the transfer belt 1 and conveyed on the same.

The document table 5 is provided parallel to the arrangement direction of the transfer belt 1 and is reciprocally driven in this direction. With respect to a color image of a document (not shown) on the document table 5, this light image is focused and formed on the photoconductor belt 8 through the speed-collecting light transmitting array 6, the filter 7, and the like. An electrostatic latent image is formed on it. This is performed for each color separation, and the electrostatic latent images corresponding to the respective colors are visualized by the color toner developing sleeves 9A, 9B, 9C of the developing device 9 by being switched to the developing portions, respectively. It has been adapted.

When the transfer sheet S is electrostatically attracted to the transfer belt 1 and is carried by the transfer belt, and the portion of the transfer section 11 is passed through, the first visible image on the photosensitive belt 8 is transferred by the transfer charger 12 to the transfer sheet 12. Is transcribed to.

During this transfer, the transfer belt 1 is driven in the direction of arrow A, and its moving direction is opposite to the forward direction of the document table 5. The document table 5 is configured to return after the forward movement is completed. At this time, that is, the rear end of the transfer paper
After passing through the transfer belt 1, the transfer belt 1 rotates in the reverse direction, and the upper belt portion moves in the direction opposite to the arrow A direction to prepare for the next transfer. When the transfer belt 1 is rotated in the reverse direction, the driven roller 3 is slightly lowered so that the contact between the toner image on the transfer paper and the photosensitive belt 8 is cut off.

Then, by repeating the same process, the second-time visible image and the third-time visible image are transferred onto one sheet of transfer paper so as not to be displaced.

After the final transfer, the transfer paper passes between the charge removal chargers-13, is provided in the transfer paper discharge direction, proceeds to the transfer paper fixing system 14 composed of a pair of rollers, and after being fixed at this portion, It is discharged to the outside of the machine. In the copying machine of this example, of the image forming system including the document table 5 and the converging optical transmission element array 6, the document table is of a reciprocating type.

A rack 17 is fixedly installed at one end of the document table 5, and is engaged with a pinion 16 directly connected to a motor 15. With respect to the motor 15 and the pinion 16 which form an example of the image forming drive system, when the motor 15 out of these rotates forward and backward, the pinion 16,
The document table 5 is reciprocally driven via the rack 17 and the like.

The wire 18 whose one end is locked to the document table 5 is an idle pulley.
19 and the pulley 20 of the drive roller 2 are wound around, and the other end is locked to one end of the spring 22.

When the motor 15 rotates forward and backward and the original table 5 is reciprocally driven, the pulley 20 is rotated via the wire 18 and the transfer belt 1 is normally and reversely driven in synchronization with the movement of the original table 5. The wire 18, the pulley 20, and the like constitute an example of a first rotation transmission system that transmits the driving force from the image forming drive system to the transfer belt 1 to drive the transfer belt in synchronization with the document table. A first drive system clutch 23 is connected to the pulley 20.

The lower fixing roller 14a that constitutes one of the transfer paper fixing systems 14
Is driven by the driving force of the motor 25 via gears 26 and 27. And these form an example of a fixing drive system.

A gear 28 is fixedly provided at one end of the fixing roller 14a.
The rotation of 8 is transmitted to a gear 31 fixed to the drive roller 2 via an idle gear 29. A second drive system clutch 24 is connected to the gear 31.

This is the first drive system clutch during image formation or transfer.
23 is in the on state, while the second drive system clutch 24 is in the off state.

Therefore, the transfer belt 1 is driven by the first rotation transmission system, and in this case, is rotated in the forward and reverse directions in synchronization with the movement of the document table 5, whereby the relative relationship between the document and the transfer sheet. There is no deviation in position.

Next, at the time of fixing, that is, when the final transfer is completed, the first drive system clutch 23 is turned off and the second drive system clutch 24 is turned on so that each clutch is turned on / off. Is being carried out.

Therefore, the transfer belt 1 is driven by the second rotation transmission system this time, and in this case, is slowly rotated only in the direction of the arrow A in accordance with the linear velocity of the fixing system.

(Effect) As described above, according to the present invention, the drive of the transfer belt is selected according to each of transfer and fixing. Therefore, during the image forming process, the movement of the original table and the transfer belt is synchronized. Is achieved, and both can be accurately aligned. Further, since the transfer belt can be run in accordance with the linear velocity of the fixing system, the transfer paper is not loosened and problems such as image rubbing can be prevented. Further, it is not necessary to match the fixing linear velocity with the image forming linear velocity after the final transfer is completed, and the transfer paper can be fed at a slow linear velocity in the fixing section for improving the fixing property. Further, the movement of the transfer belt regulated by the reciprocating stroke of the document table can be given a degree of freedom.

[Brief description of drawings]

The drawing is a perspective view of an embodiment of the present invention. 1 ... Transfer belt, 5 ... Original platen as an image forming system, 14 ...
… Transfer paper fixing system, 15 …… Motor, 16 …… Pinion, 18…
… Wire, 25 …… Motor, 28, 29 …… Gear.

Claims (1)

[Scope of utility model registration request] 1. An endless transfer belt stretched in one direction for passing a transfer sheet through a transfer section, a document table moving means for moving a document table in a direction in which the transfer belt is arranged, and the transfer belt. On the other hand, a transfer paper fixing system provided in the discharge direction of the transfer paper for fixing the transfer paper, a moving means drive system for driving the original table moving means, a fixing drive system for rotationally driving the transfer paper fixing system, A first rotation transmission system for transmitting a driving force from a moving unit driving system to the transfer belt to drive the transfer belt in synchronization with the document table moving unit, and a driving force from the fixing driving system. A second member for transmitting to the transfer belt and driving the transfer belt in synchronization with the fixing drive system.
And a rotation transmission system for switching the rotation transmission to the first rotation transmission system during transfer and to the second rotation transmission system during fixing.