JP2000281232A - Sheet material-transporting equipment and image-forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid a disturbed image caused by a fluctuated belt surface due to vibration by controlling the slippage (deviation in the belt width direction) of an endless transporting belt. SOLUTION: An endless transporting belt 9 moved in the arrow direction supports (electrostatic attraction) a sheet material to transport the sheet material to each image forming part Pa, Pb, Pc, Pd. The transporting belt 9 is wrapped around a driving roller 10 and driven rollers 11a, 11b. A horizontal region between the rollers 10, 11a transports the sheet material. The roller 11b located at an area separated from the horizontal region provides tensile force to the transporting belt 9 and regulates the slippage of the transporting belt 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile, etc., and more particularly to a sheet conveying apparatus used as means for conveying a sheet material (recording material) to an image forming section.

[0002]

2. Description of the Related Art Some image forming apparatuses transport a sheet material fed one by one to an image forming section using an endless transport belt wound around a plurality of rollers. is there. FIG. 4 shows a typical example of such an image forming apparatus. The image forming apparatus shown here is an electrophotographic full-color copying machine.

The first, second, third and fourth four image forming units Pa, Pb, Pc and Pd are provided in an image forming apparatus main body CP.
Are arranged in order in the sheet conveying direction.

Under the first, second, third and fourth image forming units Pa, Pb, Pc and Pd, sheet materials (shown in FIG. 1) fed one by one from a cassette 7a or 7b are shown. Z)
Is transported to each of the image forming units Pa, Pb, Pc, and Pd. An endless transport belt (transfer belt) 9 is used in the apparatus 100A.

[0005] The transport belt 9 is wound around a driving roller 10 and a driven roller 11. The drive roller 10 is driven by a motor 13.

The transport belt 9 is a thin dielectric belt that is driven to rotate in the direction of arrow A by a driving roller 10.
The sheet material fed out of the cassette 7a or 7b and synchronized by the registration roller pair 8 is electrostatically attracted and carried, and is sequentially conveyed to the image forming units Pa, Pb, Pc, and Pd.

The image forming units Pa, Pb, Pc, and Pd have substantially the same structure, and are formed around photosensitive drums 1a, 1b, 1c, and 1d driven to rotate in the direction of arrow B. Primary chargers 2a, 2b, 2c, and 2d for uniformly charging the photosensitive drums 1a, 1b, 1c, and 1d are provided around the photosensitive drums 1a, 1b, 1c, and 1d. Developing devices 3a, 3b, 3c and 3d for developing the electrostatic latent images formed on 1c and 1d, and transfer charging devices 4a and 4 for transferring the developed toner images of each color to a sheet material
b, 4c, 4d and the photosensitive drums 1a, 1b, 1c, 1
Cleaning device 5 for removing toner remaining on d
a, 5b, 5c, 5d are the drum rotation directions (arrow B direction)
Are sequentially arranged. Also, the photosensitive drums 1a, 1b,
Exposure optical systems 6a, 6b, 6c, 6
d is provided.

The developing device 3a contains yellow toner, the developing device 3b contains magenta toner, the developing device 3c contains cyan toner, and the developing device 3d contains black toner. .

In the present image forming apparatus, when a sheet material is placed on the transport belt 9 (electrostatic attraction), the corresponding photosensitive drum 1a, The image forming processes for 1b, 1c, and 1d are sequentially started. That is, the document transport device 200 transports a document (not shown) one sheet at a time to a document reading unit (on a platen glass). Then, this original image is transferred to the optical system 300.
Reads. The image information of each color read by the optical system 300 is projected by the exposure optical systems 6a, 6b, 6c, and 6d onto the photosensitive drums 1a, 1b, 1c, and 1d rotating in the direction of arrow B to form an electrostatic latent image. , And the latent image is
a, 3b, 3c, and 3d develop. As a result, a yellow image is formed on the photosensitive drum 1a of the first image forming unit Pa.
The photosensitive drum 1b of the second image forming unit Pb has a magenta image, the photosensitive drum 1c of the third image forming unit Pc has a cyan image, and the photosensitive drum 1 of the fourth image forming unit Pd.
A black image is formed to be shared by d.

By the movement of the conveyor belt 9, the sheet material is transferred to each of the photosensitive drums 1a of the first to fourth image forming units Pa to Pd.
１1d. In this process, the transfer chargers 4a, 4b, 4c, 4d of the respective image forming portions Pa to Pd
The photosensitive drums 1a, 1b, 1c,
The toner images of the respective colors formed on 1d are sequentially superimposed and transferred to form a full-color image.

[0011] The sheet material is the fourth most downstream image forming unit Pd.
Is separated from the conveyor belt 9 and the fixing device 14
After the toner images of the respective colors transferred in a superimposed manner in the fixing device 14 are fused and fixed,
Is discharged on top.

The image forming apparatus also includes a manual paper feed unit 16 that can externally feed sheet materials one by one.

Here, the sheet conveying apparatus 100A of the present image forming apparatus will be described in detail.

The transport belt 9 is connected to each of the image forming units Pa, Pb,
In order to convey the sheet material in a state stable to Pc and Pd, a predetermined tension must be applied to the conveyance belt 9. Here, the driven roller 11 is
To that tension. The driven roller 11 is installed so as to be movable in the direction of coming into contact with and separating from the driving roller 10, and is urged by an urging spring (coil spring) 12 in a direction away from the driving roller 10.

If the transport belt 9 is laterally displaced (deviation in the belt width direction), the image forming units Pa, Pb, P
In c and Pd, a shift occurs between the respective color images formed on the sheet material. For this reason, it is necessary to control the deviation of the transport belt 9. Here, the deviation of the conveyor belt 9 is controlled in the driven roller 11 portion. That is, the deviation regulating ribs formed over the entire periphery of both inner edges of the transport belt 9 are in contact with both end surfaces of the driven roller 11. Thereby, the shift of the transport belt 9 is regulated. The cause of the lateral displacement of the transport belt 9 is, for example, a difference in circumferential length of the transport belt 9 in the width direction, a geometrical shape deviation between the rollers 10 and 11, and the like.

[0016]

However, the conventional sheet conveying apparatus 100A has the following problems.

That is, when the deviation force of the conveyor belt 9 is large, the force (frictional force) of the deviation regulating rib abutting on the end face of the driven roller 11 is large, so that the driven roller 11 not fixed in position generates vibration. Then, this vibration is transmitted to the sheet material carrying portion of the transport belt 9. In such a case, there is a possibility that the belt surface fluctuates and the image at the time of transfer is disturbed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances, and has as its object to provide a sheet conveying apparatus which prevents an image from being disturbed due to a change in a belt surface.

[0019]

According to the present invention, there is provided a sheet conveying apparatus for conveying a sheet using an endless conveying belt wound around a plurality of rollers.

According to the present invention, in order to attain the above object, a sheet material transport area in which the transport belt carries and transports a sheet material is provided between a first roller and a second roller. It is characterized in that tension is applied to the conveyance belt at a location other than the sheet material conveyance area including the first and second rollers, thereby restricting the conveyance belt from shifting in the belt width direction.

Now, the present invention will be described in more detail.

The first roller and the second roller are rollers whose positions are fixed, and which are parallel to each other in the belt width direction.

There is provided a third roller for applying tension to the transport belt at a place other than the sheet transport area and for controlling the deviation of the transport belt in the belt width direction.

There is provided a fourth roller for adjusting the parallelism of the entire conveyance belt at a place other than the sheet material conveyance area.

The sheet conveying apparatus of the present invention conveys a sheet fed one by one to an image forming section to form an image, and more particularly, a plurality of image forming apparatuses for forming images of different colors. In an image forming apparatus in which units are sequentially arranged in a sheet material conveying direction, the image forming apparatus is used as a unit for conveying a sheet material to the image forming unit. For example, the image forming section is mainly configured with an image carrier for carrying a developer image.

[0026]

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

<First Embodiment> FIG. 1A shows an overall image forming apparatus (electrophotographic full-color copying machine) equipped with a sheet conveying apparatus 100B according to a first embodiment of the present invention. A simple schematic configuration is shown.

The basic structure of this image forming apparatus is the same as that of the above-described conventional image forming apparatus (FIG. 4) except for a part of the structure of the sheet conveying apparatus 100B of the present invention. Therefore, here, only different components of the sheet conveying apparatus 100B of the present invention will be described.

The conveying belt 9 in the sheet conveying apparatus 100B of the present invention comprises a driving roller 10 and a driven roller 11
a and 11b. The transport belt 9 electrostatically attracts and transports the sheet material in a horizontal area (sheet material transport area) wound around a driving roller (first roller) 10 and a driven roller (second roller) 11a. . In the sheet conveying apparatus 100B, the driving roller 10 and the driven roller 11a are fixed in position, and are in a relationship parallel to each other in the belt width direction.

In the sheet conveying apparatus 100B,
A driven roller (third roller) 11b located outside the horizontal area of the conveyor belt 9 applies a predetermined tension to the conveyor belt 9 and regulates the deviation of the conveyor belt 9.

The driven roller 11b is installed so as to be movable in the directions of arrows X1 and X2, and is urged in the direction of arrow X2 by an urging spring (coil spring) 12. As a result, a predetermined tension is applied to the transport belt 9.

FIG. 1 shows the deviation control for the transport belt 9.
The configuration shown in FIG. That is, the deviation regulating ribs 9a and 9b formed over the entire periphery of both inner edges of the conveyor belt 9 are in contact with both end surfaces of the driven roller 11b.

The deviation regulating ribs 9a, 9b are
The end faces 0 and 11a are not brought into contact with each other.

As described above, the sheet conveying apparatus 1 of the present invention
In 00B, a driven roller 11b installed at a place other than the sheet material transport area of the transport belt 9 causes
The tension is applied to the conveyor belt 9 and the deviation of the conveyor belt 9 is regulated. For this reason, even if the biasing force of the conveyor belt 9 is large and the driven roller 11b vibrates, the vibration is generated by the driving roller 10 and the driven roller 11a.
It is difficult to be transmitted to the sheet material transport area formed between
As a result, the transfer image is not disturbed by the fluctuation of the belt surface due to the vibration.

<Second Embodiment> FIG. 2 shows a second embodiment of the present invention.
1 shows an overall schematic configuration of an image forming apparatus (an electrophotographic full-color copying machine) including a sheet material conveying apparatus 100C according to the embodiment.

The basic configuration of the present image forming apparatus is the same as that of the above-described conventional image forming apparatus (FIG. 4), except for a part of the sheet conveying apparatus 100C of the present invention. Therefore, here, only the different components of the sheet conveying apparatus 100C of the present invention will be described.

The conveying belt 9 of the sheet conveying apparatus 100B according to the first embodiment is wound around a driving roller 10 and two driven rollers 11a and 11b. Conveyor belt 9 of device 100C
Are a driving roller 10 and three driven rollers 11a, 11
b, 11c. Driven roller (4th
This embodiment is characterized in that a roller 11c is added.

Here, the added driven roller 11
“c” is mainly used as an alignment adjusting roller for further stabilizing the movement of the conveyor belt 9. Here, the alignment adjustment refers to adjustment of the parallelism of the entire conveyor belt 9.

The driven roller 1 of this embodiment for applying tension to the conveyor belt 9 and restricting the shift of the conveyor belt 9 is described.
1b is installed so as to be movable in the directions of the arrows X3 and X4, and is urged by the urging spring 12 in the direction of the arrow X4.

<Third Embodiment> FIG. 3 shows a third embodiment of the present invention.
1 shows an overall schematic configuration of an image forming apparatus (an electrophotographic full-color copying machine) including a sheet material conveying apparatus 100D according to the embodiment.

The basic structure of this image forming apparatus is the same as that of the above-described conventional image forming apparatus (FIG. 4) except for a part of the sheet material conveying apparatus 100D of the present invention. Therefore, here, only different components of the sheet conveying apparatus 100D of the present invention will be described.

In the sheet conveying apparatuses 100B and 100C of the first and second embodiments, the driving roller 10
And a driven roller 11a constitute a sheet material transporting section of the transport belt 9, but the sheet material transporting device 1 of the present embodiment
00D, the driven roller (first roller) 11d
And the driven roller (second roller) 11a
Of the sheet material transport unit. This is a feature of the present embodiment.

In the present embodiment, the drive roller 10 for driving the transport belt 9 is disposed at a position other than the sheet transport area of the transport belt 9. Here, the driven roller 11b is disposed outside the conveyor belt 9.
In the present embodiment, tension is applied to the transport belt 9 by the driven roller 11b, and the deviation of the transport belt 9 is controlled by the driven roller 11c for alignment adjustment. The structure of the deviation control is the same as that of FIG.

In this specification, the case where the sheet conveying apparatus of the present invention is applied to an electrophotographic image forming apparatus has been described. It can be widely applied to devices and the like.

[0045]

As described above, according to the sheet conveying apparatus of the present invention, the tension is applied to the endless conveying belt that carries and conveys the sheet at a place other than the sheet conveying area. Is applied to limit the deviation of the conveyor belt, so that the vibration generated by the restriction of the conveyor belt is not transmitted to the sheet material conveyance area. As a result, the image is not disturbed due to the fluctuation of the belt surface,
High quality images can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view (FIG. 1A) showing an overall schematic configuration of an image forming apparatus including a sheet material conveying device according to a first embodiment of the present invention, and details of a main part of the sheet material conveying device. Sectional drawing which shows a structure (FIG.1 (b)).

FIG. 2 is a cross-sectional view illustrating an overall schematic configuration of an image forming apparatus including a sheet material conveying device according to a second embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating an overall schematic configuration of an image forming apparatus including a sheet material conveying device according to a third embodiment of the present invention.

FIG. 4 is a cross-sectional view illustrating an overall schematic configuration of an image forming apparatus including a conventional sheet material conveying device.

DESCRIPTION OF REFERENCE NUMERALS 1a, 1b, 1c, 1d Photoconductor drum (image carrier) 9 Conveying belt 9a, 9b Deviation regulating rib 10 Drive roller (first roller) 11a Follower roller (second roller) 11b Follower roller (Third roller) 11c driven roller (fourth roller) 11d driven roller (first roller) 100B, 100C, 100D sheet conveying device Pa, Pb, Pc, Pd image forming section

Claims (7)

[Claims] 1. A sheet material transport device for transporting a sheet material using an endless transport belt wound around a plurality of rollers, wherein the transport belt carries a sheet material and transports a sheet material. A belt is provided between a first roller and a second roller, and tension is applied to the transport belt at a location other than the sheet material transport area including the first and second rollers, and a belt width of the transport belt is provided. A sheet conveying device, wherein deviation in a direction is regulated. 2. The apparatus according to claim 1, wherein the first roller and the second roller are fixed-position rollers and rollers that are parallel to each other in a belt width direction. Sheet material transport device. 3. The image forming apparatus according to claim 2, further comprising a third roller that applies tension to the conveyance belt at a location other than the sheet material conveyance area, and controls a deviation of the conveyance belt in a belt width direction. 2. The sheet material conveying device according to 1. 4. The sheet conveying apparatus according to claim 1, further comprising a fourth roller for adjusting the parallelism of the entire conveying belt at a place other than the sheet conveying area. 5. An image forming apparatus for conveying a sheet material fed one by one to an image forming unit to form an image, wherein the sheet material is conveyed to the image forming unit. An image forming apparatus, comprising: the sheet material conveying device according to any one of the claims. 6. The image forming apparatus according to claim 5, wherein a plurality of image forming units for forming images of different colors are sequentially arranged in a sheet material conveying direction. 7. The image forming apparatus according to claim 5, wherein the image forming section is configured around an image carrier that carries a developer image.