JPH05294494A - Belt system for image former - Google Patents

Abstract

PURPOSE:To make a belt member keep the extent of sufficient strength as well as to prevent those of buckling, meandering, speed variation and adhesive strength drop from occurring by installing a reinforcing member in a backside edge of the belt member at a specified interval, and setting up a recess, being fitted in the reinforcing member in a noncontact state, in the axial end part of a roller stretching the belt member. CONSTITUTION:A transfer paper conveying belt 12 is provided with some reinforcing members 20 at a specified interval along the traveling direction at the backside edge, while the axial end part of a roller 14 stretching the belt 12 is provided with a level differential part 21 which is fitted in the reinforcing member 21 installed in the backside edge of the belt 12 in a noncontact state. Accordingly, the belt 12 has sufficient strength, and simultaneously such a possibility that deformation such as buckling or the like might be produced in an end of the belt 12 is preventable from occurring. In addition, since there is no contact between the reinforcing member and the roller 14, any possible buckling, meandering and speed variation are kept back as well as any drop in adhesive strength between the belt and the reinforcing member can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a belt device for an image forming apparatus which is used in a color image forming apparatus or the like and which causes a belt member such as a conveyor belt for conveying a transfer sheet or a belt-shaped photoconductor to run endlessly. Is.

[0002]

2. Description of the Related Art Conventionally, as a color image forming apparatus using such a belt device for an image forming apparatus, there is one shown in FIG. 8, for example. In this color image forming apparatus, a transfer paper conveyance belt 100 is supported by a plurality (three in the illustrated example) of rollers 101, 102 and 103 in a circularly movable manner, and a transfer paper (not shown) is held on the belt 100. Then, the rollers 101 and 103 are moved in the horizontal direction. Also, on the belt 100,
Four image forming units 104, 105, 1 for forming images of four colors such as cyan, magenta, yellow and black
06 and 107 are sequentially arranged along the moving direction.
Then, the image forming units 104, 105, 106 and 10 are formed on the transfer sheet held on the belt 100.
After sequentially transferring the images of cyan, magenta, yellow, and black by 7, the transfer paper on which these four color images have been transferred is separated from the belt 100, and the four color images are fixed on the transfer paper. Is configured to form a color image.

In the above-mentioned color image forming apparatus, the belt 100 for conveying the transfer paper has four image forming units 104,
Since it is necessary to convey the transfer sheet between 105, 106, and 107, the transfer sheet conveying belt 100
Has a certain length and requires a certain strength or more.

By the way, as a technique relating to the reinforcement of belt members such as the above-mentioned transfer sheet conveying belt, there is disclosed in Japanese Unexamined Utility Model Publication No.
70244, JP-A-59-155869,
Japanese Utility Model Publication No. 1-164461 and Japanese Utility Model Publication No. 2-9507.
There is one disclosed in Japanese Patent No. 0, etc.

The belt meandering preventive device disclosed in Japanese Utility Model Laid-Open No. 57-70244 described above is designed to endlessly run a belt by interposing the belt between rollers, and meanders the belt at the axial end of the roller. And a rigid portion is provided on the side edge of the belt along the longitudinal direction thereof.

The image forming apparatus disclosed in Japanese Patent Laid-Open No. 59-155869 forms an electrostatic latent image on an image carrier, develops the latent image, and then mounts it on a conveyor belt and conveys it. In an image forming apparatus that transfers a developed image to a transfer material
The belt is provided with projections or holes, and guide means for engaging with the projections or holes to prevent lateral vibration of the belt is provided.

Further, the intermediate transfer device of the electrophotographic apparatus disclosed in Japanese Utility Model Laid-Open No. 1-164461 is provided in contact with the surface of the photoconductor to copy the toner image formed on the surface of the photoconductor and feed it. In an intermediate transfer device of an electrophotographic apparatus having an intermediate transfer belt for transferring to a sheet conveyed from the side, the above intermediate transfer belt is provided with a reinforcing member that reinforces the both ends in the lateral direction. It is configured to be provided.

The sheet belt for a copying machine disclosed in Japanese Utility Model Laid-Open No. 2-95070 is stretched between a plurality of rollers and is moved by the rotation of the rollers. In the endless copying machine seat belt, the belt width of the sheet belt is formed to be substantially the same as the roller width of the roller, and reinforcing tapes are provided on both sides of the sheet belt 100 as shown in FIG. It is configured such that the member 110 is attached.

[0009]

However, the above-mentioned prior art has the following problems. That is, in the case of the device according to the above proposal, a rigid portion is provided on the side edge of the belt over the longitudinal direction thereof, a reinforcing member is provided on the belt along both ends in the lateral direction, and both sides of the belt are provided. Although it is configured to attach a reinforcing tape member, when the reinforcing member or the reinforcing tape is provided at both ends of the belt as described above, the thickness of the belt is different between the center and the end. , There will be a speed difference.

In particular, when the belt passes the roller portion located at the end of the belt, the belt bends, so that the reinforcing member and the reinforcing tape provided on the back surface of the belt contract, but the surface of the belt contracts. The reinforcing member and the reinforcing tape provided on the side expand. Therefore, the reinforcing member and the reinforcing tape provided at both ends of the belt are subjected to repeated loads such as bending and pulling, so that the belt and the reinforcing member and the reinforcing tape themselves cause buckling, meandering or speed fluctuation, There is a problem that the adhesive strength between the reinforcing member and the reinforcing tape is reduced.

Therefore, the present invention has been made to solve the above-mentioned problems of the prior art. The purpose of the present invention is to make the belt member have sufficient strength and to repeatedly bend and pull the belt member. For an image forming apparatus that can prevent a load from being applied, and can prevent buckling, meandering or speed fluctuations in the belt and the reinforcing member itself, and a decrease in adhesive strength between the belt and the reinforcing member. To provide a belt device.

[0012]

The above-mentioned technical problems are
In a belt device for an image forming apparatus according to the present invention, a belt member is stretched between at least two rollers composed of a driving roller and a driven roller, and the belt member runs endlessly as the driving roller rotates. In a belt device for use, a reinforcing member is provided at an end edge on the back surface side of the belt member at predetermined intervals along the moving direction of the belt member, and an axial end portion of a roller that stretches the belt member,
This is achieved by providing a concave portion that is fitted in a non-contact state with a reinforcing member provided on the back surface side edge of the belt member.

As the belt member, for example, a conveyor belt for conveying the transfer sheet, a belt-shaped photosensitive member, or the like is used.

The reinforcing member is provided, for example, as a member separate from the belt member, but may be provided integrally with the belt member.

[0015]

According to the present invention, the reinforcing member is provided at the rear side edge of the belt member along the moving direction of the belt member at a predetermined interval, and the axial end of the roller for stretching the belt member. The portion is provided with a step portion that fits in a non-contact state with the reinforcing member provided on the back surface side edge of the belt member.

For this reason, since the belt member is reinforced by providing a reinforcing member along the moving direction at the end portion thereof, the belt member has sufficient strength against expansion in the moving direction and the like. Even when the belt member is laterally displaced and the end portion of the belt member comes into contact with the guide member of the roller, it is possible to prevent the end portion of the belt member from being deformed such as buckling.

Moreover, a stepped portion which is fitted in a non-contact state with the reinforcing member of the belt member is provided at the axial end portion of the roller which stretches the belt member, and the reinforcing member is formed of the belt member. Since the belt members are arranged with a predetermined gap along the moving direction, even if the belt member bends when passing through the roller, the reinforcing members do not come into contact with each other or the reinforcing member and the roller. There is no difference in the moving speed of the member between the center and the end, and no contraction force or extension force acts on the belt member. Therefore, it is possible to prevent the belt member from buckling, meandering, or fluctuating in speed, and reducing the adhesive strength between the belt and the reinforcing member.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the illustrated embodiments.

FIG. 2 shows an embodiment of a color image forming apparatus to which the belt device for an image forming apparatus according to the present invention is applied.

In FIG. 2, reference numerals 4a, 4b, 4c, and 4d denote photoconductor drums on which toner images of yellow, magenta, cyan, and black colors are formed, respectively. 4c and 4d are arranged in parallel at a predetermined interval from each other. The surfaces of the photosensitive drums 4a, 4b, 4c, and 4d are uniformly charged by the primary chargers 1a, 1b, 1c, and 1d, and then,
Exposure device 2 consisting of semiconductor laser, polygon mirror, etc.
The images are sequentially exposed by a, 2b, 2c, and 2d to form an electrostatic latent image. These photosensitive drums 4a, 4
The electrostatic latent images formed on the surfaces of b, 4c, and 4d are yellow, respectively, by the developing devices 3a, 3b, 3c, and 3d.
Developed with magenta, cyan, and black color toners to form visible toner images.These visible toner images are discharged by a pre-transfer charge eliminator (not shown) if necessary.
The transfer chargers 5a, 5b, 5c and 5d are sequentially charged onto a transfer sheet (not shown) by charging.

The photosensitive drums 4a, 4b, 4c, 4d
The transfer sheet sequentially receiving the toner images is supplied from a sheet feeding cassette (not shown) and is conveyed on the transfer sheet conveying belt 12 while being electrostatically held by the charging of the adsorption charger 7. Each photosensitive drum 4a, 4b, 4
It is sequentially conveyed to the transfer position located below c and 4d. Then, the transfer paper on which the toner images of the respective colors are sequentially transferred from the photoconductor drums 4a, 4b, 4c, 4d is separated from the transfer paper carrying belt 12 and carried to a fixing device unit (not shown), and the fixing device is provided. A toner image of each color is superposed on the transfer paper by the unit to fix a color image, and a color image is formed.

On the other hand, the surface of each of the photosensitive drums 4a, 4b, 4c, and 4d on which the transfer of the toner image has been completed is cleaned by the cleaning devices 6a, 6b, 6c, and 6d to remove residual toner and the like, and then, if necessary. The erase lamp (not shown) removes electricity to prepare for the next image forming step.

In the figure, reference numerals 8 and 9 denote static eliminators for static elimination of the transfer paper and the transfer paper carrying belt 12.

By the way, in this embodiment, a reinforcing member is provided at the back side edge of the belt member along the moving direction of the belt member at a predetermined interval, and the axial end portion of the roller on which the belt member is stretched is extended. In addition, a concave portion that fits in a non-contact state with a reinforcing member provided on the back surface side edge of the belt member is provided.

That is, the transfer sheet conveying belt 12
As shown in FIG. 2, is supported by a plurality of rollers including a driving roller 13 and driven rollers 14 and 15 in a circulating manner. This belt for transferring transfer paper 1
2 is formed of, for example, a PET (polyethylene terephthalate) resin having a thickness of 75 μm.
It is stretched by 4 and 15 with a tension of about 5 Kgf. However, the thickness of the belt 12 is not limited to this, and may be set to, for example, about 50 to 200 μm.

Further, as shown in FIG. 3, the transfer sheet carrying belt 12 is provided with reinforcing members 20, 20 ... At predetermined intervals at both end edges on the back surface side along the moving direction thereof. Has been. The reinforcing members 20, 20 ... Are made of a material having a large Young's modulus E, such as metal, and are fixed to the back surface of the belt 12 by means such as adhesion. The reinforcing members 20, 20, ... Are formed with a width of 0.5 mm and a thickness of 20 μm along the moving direction, and are arranged at a pitch of 2 mm along the moving direction of the belt 12.

In this embodiment, one roller 14 which supports the transfer sheet conveying belt in a circularly movable manner.
However, a belt supporting sleeve member made of a material having flexibility is provided on the outer periphery of the shaft member in a radially outward direction, and the sleeve member is provided with a predetermined gap along the axial direction of the shaft member. It is configured to be provided.

That is, the roller 14 is provided with a metal shaft member 16 as shown in FIG. 4, and the outer periphery of the shaft member 16 is made of rubber, synthetic resin, or the like radially outward. A belt supporting sleeve member 17 made of a flexible material is projected in a plate shape. The sleeve member 17 is spirally provided in series along the axial direction of the shaft member 16 with a predetermined gap. The sleeve member 17 is a disc-shaped member that is separated from each other.
A large number of rows may be provided along the axial direction of the shaft member 16.

Further, as shown in FIG. 1, the rollers 14 for supporting the transfer sheet carrying belt 12 in a circulatory manner are provided with reinforcing members 20, 2 of the belt 12 at their axial end portions, as shown in FIG.
0 is provided with a step portion 21 that fits in a non-contact state. The diameter of the step portion 21 is set to be smaller than that of the other portions of the roller 14, and the surface of the step portion 21 of the roller 14 is prevented from coming into contact with the surfaces of the reinforcing members 20, 20 ,. ing. Further, at both ends of the roller 14, a guide member 2 as a belt deviation preventing member is provided.
2 are integrated or separated.

The stepped portion 21 of the roller is also provided on the other rollers 13 and 15 in the same manner.

In the color image forming apparatus to which the belt device for the image forming apparatus according to the present embodiment having the above-mentioned structure is applied, buckling, meandering or speed fluctuation of the belt or the like is prevented as follows. can do. That is, in this color image forming apparatus, as shown in FIG.
The rollers 13 and 14 are movably supported in a circulating manner, and a transfer sheet (not shown) is horizontally moved between the rollers 13 and 14 while being held on the belt 12. Then, the four-color images of cyan, magenta, yellow, and black formed by the photosensitive drums 4a, 4b, 4c, and 4d are sequentially transferred onto the transfer paper held on the belt 12, and then these four images are transferred. The transfer paper on which the color image has been transferred is separated from the belt 12, and the four-color image is fixed on the transfer paper to form a color image.

By the way, the belt 1 for transporting the transfer paper.
2 is provided with reinforcing members 20, 20 ... At predetermined intervals on the rear surface side edge along the movement direction thereof, and the axial end portion of the roller 14 that stretches the belt 12 is also provided. Is provided with a step portion that fits in a non-contact state with the reinforcing members 20, 20 provided on the back surface side edge of the belt 12.

Therefore, the belt 1 for transferring the transfer paper is used.
2 is a reinforcing member 20, 2 along the moving direction at its edge.
Since 0 is provided and reinforced, the belt 12 has sufficient strength against expansion in the moving direction thereof, and the belt 12 is laterally displaced so that the end portion of the belt 12 contacts the guide member of the roller. Even in such a case, it is possible to prevent the end portion of the belt 12 from being deformed such as buckling.

Moreover, the reinforcing members 20, 2 of the belt 12 are provided at the axial ends of the rollers 14 for stretching the belt 12.
0 is provided with a step portion that fits in a non-contact state, and the reinforcing members 20, 20, ... Are arranged with a predetermined gap along the moving direction of the belt 12, so that the belt 12 Even if the belt bends when passing through the roller 14, the reinforcing members 20, 20, ... Or the reinforcing members 20, 20, ... Do not come into contact with the roller 14. Therefore, the moving speed of the belt 12 is between the center and the end. And the belt 12 does not have a contracting force or an extending force. Therefore, belt 1
It is possible to prevent buckling, meandering, speed fluctuations, and reduction in the adhesive strength between the belt and the reinforcing member.

FIGS. 5 and 6 show another embodiment of the present invention. The same parts as those of the above embodiment are designated by the same reference numerals. In this embodiment, the back surface of the belt member will be described. The reinforcing member provided on the side edge is formed integrally with the belt member.

That is, in this embodiment, as shown in FIGS. 5 and 6, at both ends of the belt 12, reinforcing members 20, 20 ... Are integrally formed at the edges on the back surface side, These reinforcing members 20, 20 ... Are separated from each other by a substantially V-shaped groove 25. Therefore, the reinforcing members 20, 20, ... Are provided at predetermined intervals along the moving direction of the belt 12.

The reinforcing members 20, 20, ... Are shown in FIG.
You may form in a shape as shown in (a) and (b).

As described above, when the reinforcing members 20, 20 ... Are integrally formed with the belt 12, the belt 12 can be easily manufactured.

The reinforcing members 20, 2 for the belt 12 are
The reinforcing material 2 is mixed in the portion of 0 ...
The strength of the material of the portions 0, 20 ... May be improved.

The other structure and operation are the same as those of the above-mentioned embodiment, and the description thereof will be omitted.

In the above embodiment, the metal shaft member 2 is used as the roller 15 positioned at the peeling position of the transfer paper 10.
0 is provided on the outer periphery of the shaft member 20. A sleeve member 21 for supporting the belt, which is made of a flexible material such as rubber or synthetic resin, is provided on the outer periphery of the shaft member 20 in a plate shape. Although the case of using a roller is not limited to this, the roller 15 positioned at the peeling position of the transfer sheet 10 may be a solid cylindrical roller having no ordinary sleeve member 21. Of course, it is also good.

[0042]

According to the present invention, which has the above-described structure and operation, the belt member has sufficient strength and
It is possible to prevent repeated load of bending and pulling on the belt member, buckling, meandering or speed fluctuation occur in the belt and the reinforcing member itself, or the adhesive strength between the belt and the reinforcing member decreases. It is possible to provide a belt device for an image forming apparatus capable of preventing the above.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a belt device for an image forming apparatus according to the present invention.

FIG. 2 is a block diagram showing a color image forming apparatus to which an embodiment of the belt device for an image forming apparatus according to the present invention is applied.

FIG. 3 is a perspective view showing a belt.

FIG. 4 is a cross-sectional view showing a roller.

FIG. 5 is a sectional view showing another embodiment of the present invention.

FIG. 6 is a side view showing another embodiment of the present invention.

7 (a) and 7 (b) are cross-sectional views showing modified examples of other embodiments of the present invention.

FIG. 8 is a configuration diagram showing a color image forming apparatus to which a conventional belt device for an image forming apparatus is applied.

9 (a) and 9 (b) are a sectional view and a side view showing a conventional belt.

[Explanation of symbols]

12 belts, 14 rollers, 20 reinforcing members, 21
Step.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location G03G 15/01 114 B 15/16 21/00 119

Claims (1)

[Claims] 1. A belt device for an image forming apparatus, wherein a belt member is stretched between at least two rollers composed of a driving roller and a driven roller, and the belt member runs endlessly as the driving roller rotates. Reinforcing members are provided at the back side edge of the belt member at predetermined intervals along the moving direction, and at the axial end portion of the roller that stretches the belt member, at the back side edge of the belt member. A belt device for an image forming apparatus, which is provided with a concave portion that fits in a non-contact state with a provided reinforcing member.