JPH04158371A - Belt driving method - Google Patents

Abstract

PURPOSE:To prevent the winding kink of a belt causing rolling by driving the belt so that the belt is stopped at a position displaced from the original position where the belt is wound on a roller. CONSTITUTION:A photosensitive body belt 1 is rotated by the number corresponding to the number of copied sheets and stopped. The belt 1 is formed into a circle, its diameter is set to 80 mm, the diameter of a driving roller 12 is set to 16 mm, and the diameter ratio is 80/16=5. When the roller 5 is rotated five times under this condition, the portion 1A of the wound belt 1 is returned to the original position. The stop position of the belt 1 is changed before and after the copying process, thus the winding kind of the belt 1 is prevented or reduced, and the occurrence of rolling is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a belt driving method that prevents curling of an endless belt.

[Prior Art and Problems to be Solved by the Invention] Endless belts, which are stretched between a plurality of rollers and driven to rotate, are often used in various devices. If the belt is left untwisted for a long time, the part of the belt that is wound around the rollers will curl, and this curling will cause the belt to wave. For example, when such an endless belt-shaped photoreceptor is used as a photoreceptor in a copying machine, if the endless belt-like photoreceptor becomes wavy, a transfer failure may occur.

Therefore, Japanese Utility Model Application Publication No. 58-50462 and Japanese Patent Application Laid-open No. 1986-
Although it is possible to prevent such curling by using the belt tension release means disclosed in Japanese Patent No. 136784 and the like to release the belt tension when the belt is stopped, it is possible to prevent such curling. In this case, it is necessary to operate the belt tension release means every time the belt stops, which tends to complicate the mechanism configuration.

SUMMARY OF THE INVENTION An object of the present invention is to provide a belt driving method that makes it difficult for the belt to curl, which causes waving, without using the above-mentioned tension release means.

[Means to solve the problem]

In order to achieve the above-mentioned object, the present invention provides an endless belt that is wound around a plurality of rollers and driven to rotate. A belt driving method is proposed in which the belt is driven to a position away from the original position where the belt is wound around the roller when the belt is stopped.

〔Example〕

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

FIG. 1 is a schematic configuration diagram of a copying machine equipped with a photoreceptor belt 1, in which transfer paper is directed toward the photoreceptor belt 1 from either a lower paper feed section 2 or a separate paper feed section 3. It is designed to be sent by

FIG. 2 is a detailed view of the peripheral components of the photoreceptor belt 1.
The photoreceptor belt 1 is a unit in which the charging roller 4 and the cleaning device section 11 are integrated.

The photoreceptor belt 1 includes a driving roller 12 and a driven roller 13.
, 14, and is rotated in the direction of arrow a by the drive roller 12. When the photoreceptor belt l is rotationally driven in such a direction, the charging roller 4 made of rubber, metal, etc. rotates as the photoreceptor belt moves, and at this time, the surface of the photoreceptor belt becomes uniform. charged. After this charging, exposure is performed at the exposure section 6, so that an electrostatic latent image is formed on the surface of the photoreceptor belt 1.

The electrostatic latent image is developed by a unitized developing device 7, and this developed image is transferred to the transfer device 10 onto a transfer paper P fed at a predetermined timing by a pair of registration rollers 8.
Transcribed by. The transfer paper on which the developed image has been transferred is discharged onto a tray 16 through a fixing device section 15 shown in FIG. On the other hand, the toner remaining on the photoreceptor belt 1 after the transfer is removed by the cleaning device section 11, and the removed toner is carried out of the cleaning device section by the toner conveying member 17 consisting of a coil or a screw member. be discharged. In FIG. 1, the reference numeral 18 is a static eliminator, by which the surface of the photoreceptor belt 1 is brought into a static neutralized state.

Further, the eraser indicated by the reference numeral 5 serves to eliminate static electricity from the non-image area on the photoreceptor belt 1. In FIG. Conventionally, when the number of copies is one, the photoreceptor belt 1 rotates once and stops, and when the number of copies is two, it rotates twice. It had stopped. That is, the photoreceptor belt 1 rotates by a number equivalent to the number of copies and then stops.

Now, the belt part that is wrapped around the drive roller 12 is referred to as the "wrapping belt part". With the start of copying, the photoreceptor belt 1 starts to rotate, and the belt part that is wrapped around the drive roller 12 corresponds to the number of copies to be made. When it stops after rotating as many times as
The conditions for the wrapping belt portion IA to return to the original wrapping portion position are as follows.

Now, if the photoreceptor belt 1 has a circular diameter of 80 m and the drive roller 12 has a diameter of 16 m+, the diameter ratio will be 80/16=5. If converted by the director, the photoreceptor belt 1 becomes 80π (251, 33) and the drive roller 12 becomes 16π, so the circumference ratio becomes 80π/16π, which is 5.

Under such conditions, when the drive roller 12 rotates five times, the wrapping belt portion IA returns to its original position. That is, when the drive roller 12 rotates by an integral multiple of 1 or more of the circumferential length ratio, the wrapped belt portion IA
returns to its original position.

If the wrapping belt portion IA is configured to return to its original position in this way, for example, if the copying machine is left unattended for a long time, the wrapping belt portion IA will inevitably return to its original position.
It tends to become curly.

When such curling occurs, the belt itself becomes wavy, which may cause problems such as poor transfer.

In this example, the stopping position of the photoreceptor belt is changed before and after the copying process to prevent or reduce the tendency of the belt to curl, thereby suppressing the occurrence of such waving.

This means that the total number of rotations of the drive roller 12 from when the photoreceptor belt 1 starts operating until it stops is
This can be achieved by controlling the drive of the belt 1 so that the ratio of the circumferential lengths of the photoreceptor belt and the driving roller is not an integral multiple of 1 or more.

For example, if the endless belt, such as a photoreceptor belt, is rotated until the wrapping belt part returns to its original position, and then the endless belt is rotated until the wrapping belt part comes off the roller. good.

That is, FIG. 3 shows the photoreceptor belt 1 in FIG. 2 viewed from the direction indicated by the arrow, and assuming that the image forming width on the photoreceptor belt is W, the belt side outside this image forming width is A marking 19 is attached to the end. This marking 19 is detected by a reflective photosensor (not shown) installed on the main body of the copying machine, and upon this detection, the copying process is started. That is, the home position of the belt is determined, and the belt rotates from that home position at the start of the copying process.

A pulse motor 21, which is a drive source for driving the photoreceptor belt 1, is connected to one end of the roller shaft 12a of the drive roller 12, and a rotary encoder 22 is attached to the other end.

When the above-mentioned photosensor detects the marking 19 and presses the print button (not shown) of the copying machine, the photosensitive belt 1 starts rotating 5, and when it rotates by a number corresponding to the number of copies, copying ends. However, at this time, the marking 19 is detected by the photosensor, and at this detection position, the photosensitive belt 1 returns to the home position, and the wrapping belt portion IA also returns to its original position.

At this point, the photoreceptor belt 1 either stops and rotates again, or continues to rotate and wrap around the belt portion I.
When A comes to a position where it is removed from the drive roller 12, the photoreceptor belt stops. The rotary encoder 22 measures the rotational speed or rotation angle of the drive roller 12, and this measured value is output to a control circuit (not shown) to determine the stop position of the belt so that it comes off the drive roller 12. Next, when the photoreceptor belt 1 is operated, a predetermined image forming operation may be started when the marking 19 is detected by the photosensor. An example of such a control circuit is a commercially available random number generation program.

In this example, the belt stops at different positions before and after the copying process, and at the end of copying, the wrapping belt part IA is removed from the drive roller 12, so the belt is less likely to curl and its waving is prevented. Or, it can be reduced, and the occurrence of problems such as poor transfer can be avoided. Note that the driven rollers 13 and 14 (Fig. 2) have the same diameter as the drive roller 12, and similarly, the part of the belt wrapped around that part is detached from the roller when copying is completed. .

In the embodiments described above, a photoreceptor belt is used as an endless belt, but when it is used as a transfer paper conveyor belt or a transfer belt, waving is prevented, so the transfer paper conveyance function is improved. etc. can be successfully achieved. In any case.

Since there is no need for belt tension release means, the configuration is simple and can contribute to further cost reduction.

〔Effect of the invention〕

According to the present invention, it is possible to provide a belt driving method that is less likely to cause windings that cause belt waving.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of a copying machine equipped with a photoreceptor belt;
Figure 2 is a detailed view of the peripheral components of the photoreceptor belt;
The figure is a perspective view of the belt portion on the drive roller side of the photoreceptor belt. 1... Photoreceptor belt IA as an endless belt... Winding belt portion 12.13.14... Roller agent Patent attorney Norihiro Hoshino 27 Ogata Atsushi δ Figure

Claims (1)

[Claims] An endless belt that is stretched between a plurality of rollers and driven to rotate, wherein a portion of the belt that is wound around the roller when the belt is started is wound around the roller when the belt is stopped. A belt drive method in which the belt is driven to a position away from its original position.