JPH09185215A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high quality image free of a transfer disturbance by easily preventing the vibration of the contact part of a skew restriction means, which restricts and prevents skew of a carrying belt, with the carrying belt from being transmitted to a transfer material on the carrying belt, thereby transferring a toner image onto the transfer material without disturbing it. SOLUTION: A transfer-material carrying means is obtained by stretching the carrying belt 8 between follower rollers 9a and 9b, set apart on the upstream side, and a follower roller 9c and driving roller 10, set apart on the downstream side. The skew restriction means is obtained by making a row of evenly-spaced perforations 81 into each edge of the carrying belt 8, and by forming sprockets 91, which engage with the perforations 81, onto each of the edges of the lower follower rollers 9b and 9c which do not face a photoreceptor drum. The upper follower roller 9a and upper driving roller 10 which face the photoreceptive drum are not provided with sprockets.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a full-color or full-color image forming method in which a toner image is formed on an image bearing member by an electrophotographic recording system or an electrostatic recording system and the toner image is transferred onto a transfer material to obtain an image. The present invention relates to an image forming apparatus such as a mono-color copying machine or a printer, and particularly to an image forming apparatus that conveys a transfer material to a transfer position by a conveyor belt.

[0002]

2. Description of the Related Art An image forming apparatus employing an electrophotographic recording method forms a latent image on a photosensitive drum as an image carrier using light, magnetism, electric charge, and the like, and develops the latent image to form a toner. An image forming unit for visualizing the image, a transfer material conveying unit for conveying the transfer material to a transfer position of the image forming unit, and a fixing unit for fixing the toner image to the transfer material on which the toner image has been transferred at the transfer position. ing.

As the transfer material transporting means, a belt-like transporting member, that is, a transfer material transporting belt is used from the viewpoint of transportability, and an image forming portion of each color is formed on the transporting belt along the transporting material. It The transfer material, for example, recording paper is held on the conveyor belt by electrostatic attraction, and is sequentially conveyed by the rotation of the conveyor belt to the transfer position of the image forming portion of each color and further to the fixing device.

The above-mentioned conveying belt is constructed as a transfer material conveying means which is stretched and supported around one driving roller and at least two driven rollers and is endlessly rotated. The conveyor belt is designed to be stretched with a constant force so that the conveyor belt does not sag between the drive roller and the driven roller, which allows the conveyor belt to move at a constant speed from the image forming unit on the most upstream side. The movement to the image forming unit on the downstream side is guaranteed.

Toners of respective colors formed on the image carrier of each image forming section are sequentially attached to the recording sheet that is adsorbed and held on the conveyor belt and conveyed to the transfer position of each image forming section. Is transferred and superimposed. The paper to which the toner images of the respective colors have been transferred is formed into a full-color print image by mixing the toner images of the respective colors in the fixing device and fixing the toner images to the paper.

In order to prevent the transfer belt from slipping from the drive roller and the driven roller, the transfer material transfer means is prevented from being biased by the external force during long-time rotation or jam processing. In addition, a deviation control means is installed.

More specifically, the deviation control means (1) provides a plurality of perforations (feed holes) at regular intervals at both edges or one edge of the conveyor belt, and a sprocket meshing with the perforations is used as a drive roller or a sprocket. (2) A flange is provided on both edges of the drive roller, etc., and both edges of the conveyor belt are sandwiched by the flanges, so as to prevent the conveyor belt from being displaced. (3) Ribs are provided on the inner peripheral surface side of both edges of the conveyor belt, and both edges of the drive roller and the like abut against the ribs toward the outside, thereby deviating the deviation of the conveyor belt. Examples of restricting and preventing

[0008]

As described above, in the case of (1), the conventional deviation regulating means is constructed by contacting the perforations provided on the conveyor belt with the sprockets provided on the driving roller or the driven roller. , (2)
In case (3), the edge of the conveyor belt comes into contact with the flange provided on the driving roller, and in case (3), the rib provided on the conveyor belt comes into contact with the end portion of the driving roller or the driven roller. The deviation of the conveyor belt is regulated.

Therefore, in the case where the above-mentioned deviation regulating means is provided on at least one of the driving roller and the driven roller on the side facing the photosensitive drum, when the contact portion vibrates, vibration vibrates the conveyor belt. There is a problem that the quality of the obtained image is deteriorated because the toner image is transferred to the recording sheet on the conveying belt and disturbs the transfer of the toner image to the sheet.

An object of the present invention is to easily prevent the vibration of the contact portion of the deviation regulating means with the transfer belt from being transmitted to the transfer material on the transfer belt, and transfer the toner image onto the transfer material without any disturbance. An object of the present invention is to provide an image forming apparatus capable of obtaining a high-quality image without transfer disorder.

[0011]

The above object is achieved by an image forming apparatus according to the present invention. In summary, the present invention holds at least one image carrier on which an image is formed and a transfer material for transferring a toner image on the image carrier,
An endlessly rotating conveyor belt that conveys to a transfer position facing the image carrier, at least one drive roller that supports and drives the conveyor belt, and at least two driven rollers that stretch and support the conveyor belt. In an image forming apparatus having a deviation regulating means for preventing the conveyor belt from falling off the rollers due to one-sided displacement, at least one of the rollers is located on the side opposite to the side facing the image carrier. The deviation regulating means regulates the deviation of the conveyor belt at the roller located on the opposite side.

According to one aspect of the present invention, the deviation regulating means has feed holes provided in one or two rows at equal intervals on both edges or one edge of the conveyor belt, and on the opposite side. It comprises a sprocket which is provided on both edges or one edge of the positioned roller and which meshes with the feed hole. According to another aspect, the deviation regulating means includes a flange portion that is provided at both edge portions of the roller located on the opposite side and that sandwiches both end portions of the conveyor belt. According to still another aspect, the deviation regulating means includes a rib provided on the inner peripheral surface side of both edge portions of the conveyor belt and a roller located on the opposite side, and is located on the opposite side. The roller is wider than the roller located on the side facing the image carrier of the rollers, and the roller located on the opposite side abuts the rib toward the outside.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings.

Embodiment 1 The present invention can be applied to an image forming apparatus of a type in which a transfer belt is used as a transfer material transfer means, and an image carrier is arranged on the transfer belt. It can be preferably embodied in a full-color image forming apparatus in which a plurality of image carriers are installed on a conveyor belt along the same. A schematic configuration diagram of the image forming apparatus of the present invention is shown in FIG. The image forming apparatus is a full-color copying machine.

As shown in FIG. 1, four image forming sections Pa, Pb, Pc and Pd are provided side by side in an apparatus main body 18 of the present image forming apparatus. , Below these image forming portions Pa to Pd,
A recording paper conveyance belt 8 passing through d is installed. The conveyor belt 8 is formed in an endless shape, and the first image forming unit P
Horizontal driven roller 9 installed vertically on the upstream side of a.
a, 9b, a horizontal driven roller 9c vertically installed on the downstream side of the fourth image forming portion Pd, and a driving roller 10 so as to be stretched, supported, and endlessly rotated in the arrow A direction. It is configured as a material conveying means.

Image forming units Pa, Pb, Pc and Pd
Have substantially the same configuration. Each image forming unit P
a, Pb, Pc, and Pd are provided with photosensitive drums 1a, 1b, 1c, and 1d that are driven to rotate in the direction of arrow B, and above the photosensitive drums 1a to 1d, the photosensitive drums 1a to 1d are provided.
An exposure lens system 12 that forms an electrostatic latent image by performing image exposure on d is provided. The exposure lens system 12 is composed of an imaging lens and a laser beam scanner.

Around the photosensitive drums 1a, 1b, 1c and 1d, primary chargers 2a, 2b, 2c and 2 which uniformly charge the photosensitive drums in the rotation direction thereof.
d, developing devices 4a, 4b, 4c and 4d for developing the electrostatic latent image formed on each photosensitive drum, and a transfer charging device 5 for transferring the toner image of each color obtained by the development onto the recording paper.
a, 5b, 5c and 5d, cleaning devices 6a, 6b and 6c for removing the transfer residual toner on the respective photosensitive drums
And 6d are installed.

The developing device 4a is provided with yellow toner, the developing device 4b is provided with magenta toner, and the developing device 4c is provided.
Contains cyan toner, and the developing device 4d contains black toner.

In the image forming apparatus having the above-described structure, when the recording paper from the cassette 3 is supplied and held by the registration roller 11 on the conveyor belt 8 which rotates in the direction of arrow A, the recording paper is recorded by the conveyor belt 8. With the move,
Image formation is sequentially started on the photosensitive drums 1a, 1b, 1c and 1d of the corresponding image forming portions Pa, Pb, Pc and Pd. By this image formation, the photosensitive drum 1
a has a yellow toner image, the photosensitive drum 1b has a magenta toner image, and the photosensitive drum 1c has a cyan toner image.
A black toner image is formed on the photosensitive drum 1d.

The recording paper sequentially passes under the photosensitive drums 1a, 1b, 1c, and 1d as it is moved by the conveyor belt 8, and during the passage, the transfer charger 5a on the inner peripheral surface side of the conveyor belt 8. By the action of 5b, 5c and 5d, the toner images on the photosensitive drums 1a, 1b, 1c and 1d are sequentially superposed and transferred onto the recording paper.

In this way, the final fourth image forming portion Pd
After passing through the recording paper, the recording paper is separated from the conveying belt 8 and sent to the fixing device 7, where the toners of the respective colors are melted to be mixed and fixed on the paper, and a full-color print image is formed. It is discharged to 13.

The present invention is characterized in that the position of the roller for controlling the deviation of the conveyor belt is devised.
The deviation regulating means in this embodiment will be described with reference to FIG. FIG. 2A shows the conveyor belt 8 of FIG.
It is the front view seen from the upstream side in the direction. FIG. 2B is a sectional view of the conveyor belt 8 of FIG. 1 seen from the upstream side at a position D between the third and fourth image forming units Pc and Pd on the way.

As shown in FIG. 2, in this embodiment, perforations (feed holes) 81 are formed on both edges of the conveyor belt 8.
Sprocket 91 meshing with the perforations 81 is provided in a row at regular intervals, and a lower driven roller 9b not facing the upstream photosensitive drum 1a and a lower driven roller 9b not facing the downstream photosensitive drum 1d. By providing the rollers 9c on both edges, a deviation regulating means is configured,
The deviation of the conveyor belt 8 is regulated and prevented.

The upper driven roller 9a facing the upstream photosensitive drum 1a and the upper driving roller 10 facing the downstream photosensitive drum 1d are not provided with sprockets. Therefore, the vibration generated when the perforations come into contact with the sprockets does not occur on the photosensitive drums 1a to 1d side of the conveyor belt 8, and the vibration is not transmitted to the recording paper on the conveyor belt 8.

Therefore, according to this embodiment, the photosensitive drum 1
The toner images on a to 1d can be transferred onto the recording paper without causing transfer disorder, and a high-quality image without transfer disorder can be obtained.

In the above, the perforations 81 are provided at both edges of the conveyor belt 8, and the sprocket 9 meshed with the perforations 81 at both edges of the driven rollers 9b and 9c.
However, the perforation 81 and the sprocket 91 may be provided only on one side. Further, the sprocket 91 may be provided only on one of the driven rollers 9b or 9c.

Embodiment 2 FIG. 3 shows a deviation regulating means in another embodiment of the present invention. FIG. 3A is a front view of the conveyor belt 8 of FIG. 1 viewed from the upstream side in the direction C of FIG. FIG. 3B is a sectional view of the conveyor belt 8 of FIG. 1 seen from the upstream side at the position D between the third and fourth image forming units Pc and Pd on the way.

In this embodiment, on both edges of the lower driven roller 9b which does not face the upstream photosensitive drum 1a and the lower driven roller 9c which does not face the downstream photosensitive drum 1d,
A flange 92 having a diameter larger than those of the rollers is provided, and the flanges 92 on both edges of the driven rollers 9b and 9c are provided.
The conveyance belt 8 is sandwiched between them to constitute a deviation regulation means, which regulates and prevents the deviation of the conveyance belt 8.

The upper driven roller 9a facing the upstream photosensitive drum 1a and the upper driving roller 10 facing the downstream photosensitive drum 1d are not provided with flanges.
For this reason, the vibrations that occur when the flange and the edge of the conveyor belt contact each other are caused by the photosensitive drums 1a to 1d of the conveyor belt 8.
Is not generated on the side, and vibration is not transmitted to the recording paper on the conveyor belt 8.

Therefore, also in the present embodiment, as in the case of the first embodiment, the toner images on the photosensitive drums 1a to 1d can be transferred onto the recording paper without any disturbance to obtain a high quality image.

Embodiment 3 FIG. 4 shows a deviation regulating means in another embodiment of the present invention. FIG. 4A is a front view of the conveyor belt 8 of FIG. 1 viewed from the upstream side in the direction C of FIG. 1. FIG. 4B is a cross-sectional view of the conveyor belt 8 of FIG. 1 at the position D between the third and fourth image forming units Pc and Pd on the way, similarly viewed from the upstream side.

In this embodiment, elastic ribs 82 are provided in one row on the inner peripheral surface sides of both edges of the conveyor belt 8, and the lower driven roller 9b not facing the upstream photosensitive drum 1a and the downstream driven roller 9b. The width L1 of the lower driven roller 9c that does not face the photosensitive drum 1d is the roller width of the upper driven roller 9a that faces the upstream photosensitive drum 1a and the roller width of the upper drive roller 10 that faces the downstream photosensitive drum 1d. It is made longer than L2 to configure the deviation regulating means.

That is, the driven rollers 9b and 9c are sandwiched between the elastic ribs 82 of the conveyor belt 8 and
By pushing the ends of b and 9c to the elastic ribs 82 toward the outside, the deviation and the prevention of the deviation of the conveyor belt 8 are performed, and the driven roller 9a and the drive roller 10 do not contact the conveyor belt 8. I am trying.

Therefore, the vibration generated when the rib and the roller end contact each other is generated by the vibration of the photosensitive drum 1 of the conveyor belt 8.
Since it does not occur on the side of a to 1d and the vibration is not transmitted to the recording paper on the conveyor belt 8, the toner images on the photosensitive drums 1a to 1d are transferred onto the recording paper without disturbance as in the first embodiment. , You can get high quality images.

In the above-mentioned embodiment, the case where the transfer belt 8 is wound around the driven rollers 9a, 9b and 9c and the driving roller 10 to constitute the transfer material transfer means has been described. The same applies to a transfer material conveying means having a structure in which 8 is wound around at least one driving roller and two driven rollers, and in the roller positioned on the side opposite to the side facing the photosensitive drum, the deviation regulating means. The same effect can be obtained by taking the same as above.

[0036]

As described above, according to the present invention,
Since the deviation regulation means of the conveyor belt is not on the side of the conveyor belt facing the image carrier, the deviation of the conveyor belt is prevented from being generated on the image carrier side of the conveyor belt due to vibration caused by prevention and prevention of deviation. By eliminating the vibration of the transfer material on the conveyor belt, the toner image on the image carrier can be transferred without disturbance.
It is possible to obtain a high-quality image without transfer disorder.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of an image forming apparatus of the present invention.

FIG. 2 is an explanatory diagram showing a conveyance belt deviation regulating means in the image forming apparatus of FIG.

FIG. 3 is an explanatory view showing a deviation regulating means of a conveyor belt according to another embodiment of the present invention.

FIG. 4 is an explanatory view showing a deviation regulating means of a conveyor belt according to still another embodiment of the present invention.

[Explanation of symbols]

 1a to 1d Photosensitive drum 8 Conveyor belt 9a to 9c Driven roller 10 Drive roller 81 Perforation 82 Elastic rib 91 Sprocket 92 Flange Pa to Pd Image forming unit

Claims (4)

[Claims] 1. An endless rotation for holding at least one image carrier on which an image is formed and a transfer material for transferring a toner image on the image carrier, and transporting the transfer material to a transfer position facing the image carrier. Transport belt, at least one drive roller that supports and drives the transport belt, at least two driven rollers that support and stretch the transport belt, and the transport belt from falling off from these rollers due to deviation. In the image forming apparatus provided with the deviation regulating means for preventing, at least one of the rollers is located on the side opposite to the side facing the image carrier, and the deviation regulating means is located on the opposite side. An image forming apparatus, characterized in that the conveyance roller regulates deviation of the conveying belt. 2. The deviation regulating means comprises feed holes provided in one or two rows at equal intervals on both edges or one edge of the conveyor belt, and both edges of a roller located on the opposite side. The image forming apparatus according to claim 1, further comprising: a sprocket that is provided on the edge portion or one edge portion and that meshes with the feed hole. 3. The image forming apparatus according to claim 1, wherein the deviation regulating means is a flange portion which is provided at both edges of the roller located on the opposite side and which sandwiches both end portions of the conveyor belt. 4. The deviation regulating means comprises a rib provided on the inner peripheral surface side of both edge portions of the conveyor belt and a roller located on the opposite side, and the roller located on the opposite side is The image forming apparatus according to claim 1, wherein the roller has a width larger than that of the roller positioned on the side facing the image carrier, and the roller positioned on the opposite side abuts the rib toward the outside.