JPH07181836A - Image forming device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide an image forming apparatus that is downsized and generates less ozone, and is further downsized by reducing the number of parts, and the cost is reduced. The transfer roller 5 is pressed against the movable supporting roller 10 via the belt-shaped photoreceptor 1 by the action of the compression spring 11, so that the movable supporting roller is driven by the component force generated at the pressing portion. 10 is urged to the left in the figure to apply tension to the belt-shaped photosensitive member 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a belt-shaped latent image carrier having flexibility and a transfer roller to which a bias voltage is applied.
The present invention relates to an image forming apparatus of a type in which a toner image formed on a latent image carrier is transferred onto a transfer material by passing a transfer material between the transfer material and the transfer material.

[0002]

2. Description of the Related Art It is well known in the prior art to use the above format in an electrophotographic image forming apparatus such as a laser printer. Hereinafter, an example of a conventional image forming apparatus will be described with reference to the drawings. In FIG. 3, a belt-shaped photosensitive member 1 which is a latent image carrier is provided with a driving roller 8 driven by a driving means (not shown), driven rollers 9 and 11 rotatably supported, and movably provided. The movable support roller 10 is wound around the movable support roller 10. At the time of image formation, the belt-shaped photosensitive member 1 rotates clockwise in the drawing as the drive roller 8 rotates, and a developed image is obtained on the surface under the action of latent image forming means and developing means (not shown). Further, the belt-shaped photosensitive member 1 rotates clockwise in the figure, and the toner image formed on the belt-shaped photosensitive member 1 reaches the pressure contact portion between the belt-shaped photosensitive member 1 and the transfer roller 5. At this time, the transfer material is conveyed to the pressure contact portion by a conveying means (not shown), and the developed image is transferred to the transfer material by the action of the voltage applied to the transfer roller 5. Then, the transferred toner image becomes a fixed image by the action of fixing means (not shown).

Here, the belt-shaped photosensitive member 1 is required to be wound with a predetermined tension in order to receive the action of the process means such as latent image formation and development as described above. This is also essential because the belt-shaped photoreceptor 1 rotates uniformly at a predetermined speed. Therefore, in the apparatus shown in FIG. 3, the movable support roller 10, which is one of the rollers supporting the belt-shaped photosensitive member 1, is given an elastic force in a predetermined direction by the compression spring 13. There is.

Regarding the transfer action by the transfer roller 5, the transfer efficiency is closely related to the nip width due to the deformation of the transfer roller 5 caused by the pressure contact force with respect to the belt-shaped photoreceptor 1. Therefore, the transfer roller needs to be pressed against the belt-shaped photoconductor 1 with a constant pressure contact force, and the transfer roller 5 is given an elastic force in a predetermined direction by the compression spring 12. .

In the above-mentioned image forming apparatus,
Since the belt-shaped photosensitive member is used as the latent image carrier, various shapes can be formed depending on the arrangement of the supporting member. Therefore, the arrangement of various process means is not restricted by the shape of the photoconductor, and the size of the apparatus can be easily reduced.

Further, in the above-mentioned image forming apparatus, since the transfer roller is used as the transfer means, the amount of ozone generated is much smaller than in the case where the conventional corona discharge transfer apparatus is used.

[0007]

However, in the conventional image forming apparatus, the belt-shaped photosensitive member 1 and the elastic force-applying member for applying the tension to the belt-shaped photosensitive member 1 are applied to the belt-shaped photosensitive member 1 with a constant pressure contact force. An elastic force imparting member for pressing the body 1 is required. As a result, the number of parts increases, the cost increases, and the size of the device increases.

The present invention has been made in view of the above points, and is an image forming apparatus that is downsized and produces a small amount of ozone. By reducing the number of parts, the image forming apparatus is further downsized and the cost is reduced. Another object of the present invention is to provide an image forming apparatus.

[0009]

In order to achieve the above object, the present invention provides a belt-shaped latent image carrier having flexibility,
A plurality of rollers for supporting the latent image carrier, the plurality of rollers including one movable support roller arranged so as to be movable in a direction in which tension is applied to the latent image carrier. A latent image forming means for forming a latent image on the latent image carrier, a developing means for developing the latent image formed on the latent image carrier, and a developed image formed on the latent image carrier An image forming apparatus having a transfer roller for electrostatically transferring
The transfer roller is disposed so as to be in pressure contact with the movable support roller via the latent image carrier, and the movable support roller applies tension to the image carrier by the pressure contact. An image forming apparatus urged by an elastic force applying member is provided.

[0010]

According to the present invention, the tension of the belt-shaped latent image bearing member can be obtained at the same time by the action of the elastic force imparting member for pressing the transfer roller to the belt-shaped latent image bearing member, and the number of parts can be reduced. Be reduced.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the accompanying drawings. FIG. 1 is a configuration diagram of a main part showing an embodiment of an image forming apparatus of the present invention.

In FIG. 1, a belt-shaped photosensitive member 1 which is a belt-shaped latent image carrier is wound around a plurality of supporting rollers, and the plurality of supporting rollers are driven by a driving means (not shown). It comprises a drive roller 8, driven rollers 9 and 11 that are rotatably supported, and a movable support roller 10 that is rotatably and movably arranged in the left-right direction in the drawing. When the image is formed, the drive roller 8 is rotated to rotate the belt-shaped photosensitive member 1 clockwise in the drawing.

At the time of image formation, the belt-shaped photoreceptor 1 is first charged with a surface potential of -1100 V by the action of the charging device 2.
Next, the exposure device 3 forms a latent image. The exposure apparatus is composed of, for example, a laser exposure apparatus. At the time of image formation, digital recording image information sent to the image forming apparatus is received by a line driver circuit (not shown) and amplified by a laser driver circuit (not shown). The digital recording image information is a 1-bit (recording / non-recording) binary signal per pixel, and the laser driver circuit emits a laser diode (not shown) in response to the binary signal. Energize. The laser light emitted from the laser diode is focused and irradiated on the belt-shaped photosensitive member 1.

Here, the surface potential of the belt-shaped photosensitive member 1 in the portion irradiated with light (image portion) is 0 to -290V,
Since a developing bias of -800 V is applied to the developing device 4 provided on the downstream side of the belt-shaped photosensitive member 1 in the rotation direction, the toner negatively charged by the developing device 4 is attached. On the other hand, the non-image portion is not irradiated with light and the surface potential of the belt-shaped photosensitive member 1 remains at about -1100 V, so that the toner charged in the negative by the developing device 4 does not adhere.

The belt-shaped photoreceptor 1 carrying the developed image developed by the developing device 4 further rotates in the clockwise direction in the figure and reaches the pressure contact portion between the belt-shaped photoreceptor 1 and the transfer roller 5. At this time, a timing at which the leading edge of the transfer sheet and the leading edge of the toner image on the belt-shaped photoreceptor 1 are aligned with the pressure contact portion between the belt-shaped photoreceptor 1 and the transfer roller 5 by a conveying means (not shown) It is carried by and is held between the press contact parts. The transfer roller 5 has a configuration in which a conductive elastic member is wound around the outer circumference of a metal cored bar, and a voltage having a polarity different from that of the toner on the belt-shaped photosensitive member 1 is applied to the transfer roller 5. As a result, the toner image on the belt-shaped photoconductor 1 is transferred to the transfer paper.

Then, the transfer paper on which the toner image has been transferred is separated by the curvature of the belt-shaped photoreceptor 1 and conveyed to a fixing device (not shown). Here, the toner image on the transfer paper is fused with the transfer paper under the action of heat and pressure to form a fixed image. On the other hand, the belt-shaped photoconductor 1 further rotates clockwise in the figure,
The toner remaining untransferred on the belt-shaped photosensitive member 1 is removed by the action of the cleaning device 6, and then the residual charge remaining on the surface is erased by the action of the static eliminator 7. The image forming operation ends.

Here, in the image forming apparatus of the present invention, the shaft of the movable supporting roller 10 is supported by the elongated hole, and the movable supporting roller 10 is provided so as to be movable in the lateral direction in the drawing.
The transfer roller 5 is provided so as to be movable in the vertical direction in the figure, and is biased upward in the figure by a predetermined force by a compression spring 12 which is an elastic force applying member. Therefore, the driven roller 10 and the transfer roller 5 via the belt-shaped photoreceptor 1
In the pressure contact portion, the driven roller 10 is urged to the left side in the figure by the component of the pressure contact force of the transfer roller 5, and the belt-shaped photoreceptor 1 is given a predetermined tension. Also, the transfer roller 5
Since a predetermined nip is formed by contacting the belt-shaped photosensitive member 1 with a predetermined pressure, good transfer is performed.

With the above-described structure, the transfer roller 5 is pressed against the belt-shaped photosensitive member 1 and the belt-shaped photosensitive member 1 is pressed only by the compression spring 12 that applies a predetermined force to the transfer roller 5. Stretching is possible, the mechanism is simplified, and the cost can be reduced.

In this embodiment, the case where the number of the supporting rollers around which the belt-shaped photosensitive member 1 is wound is four has been described.
As shown in FIG.
Even if the number of lines is two, similarly good results can be obtained.

[0020]

According to the present invention, since the belt-shaped latent image carrier having flexibility and the transfer roller are used, the image forming apparatus is downsized and generates less ozone. It is possible to provide an image forming apparatus which is further miniaturized and whose cost is reduced by reducing the number.

[0021]

[Brief description of drawings]

FIG. 1 is a main part configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a main part configuration diagram showing a first embodiment of the present invention.

FIG. 3 is a main part configuration diagram showing a conventional example.

[Explanation of symbols]

 1 Belt-shaped Photoreceptor 2 Charging Device 3 Exposure Device 4 Developing Device 5 Transfer Roller 6 Cleaning Device 7 Electrification Device 8 Drive Roller 9, 11 Driven Roller 10 Movable Support Roller 12, 13 Compression Spring

Claims (1)

[Claims] 1. A belt-shaped latent image carrier having flexibility,
A plurality of rollers for supporting the latent image carrier, the plurality of rollers including one movable support roller arranged so as to be movable in a direction in which tension is applied to the latent image carrier. A latent image forming means for forming a latent image on the latent image carrier, a developing means for developing the latent image formed on the latent image carrier, and a developed image formed on the latent image carrier An image forming apparatus having a transfer roller for electrostatically transferring
The transfer roller is disposed so as to be in pressure contact with the movable support roller via the latent image carrier, and the movable support roller applies tension to the image carrier by the pressure contact. An image forming apparatus characterized by being urged by an elastic force applying member.