JP2000072272A - Endless belt carrying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain the occurrence of meandering phenomenon by a carrying belt by means of simple constitution, and kept damage to the ribs of the carrying belt to the minimum. SOLUTION: An off-set correction roll 14 is formed out of an elastic member, a plurality of disc parts 6 and slit parts 8, which are formed in the radial direction in a round slice shape each, are provided in parallel in the axial direction over its surface side, and flanges 4a and 4b formed out of rigit bodies, are provided at both the ends of the roll. When the off-set of the carrying belt 11 is advanced to the direction A, loading is applied tot the flange 4b, return force in the direction B as a reaction acts on the carrying belt 11 so as to let the contacting pressure of a contacting surface 7 be thereby increased. However, since the disc parts 6 are displaced to the direction B, the carrying belt 11 is pushed back to the direction B so as to allow the contacting pressure of the contacting surface 7 to be decreased, so that damage to the end parts of the belt due to abrasion can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus such as a copying machine, a facsimile, a printer, and the like. Endless belt transport device.

[0002]

2. Description of the Related Art In an image forming apparatus, for example, a charge corotron, an exposure device, a developing device,
A transfer corotron, a cleaning device, a static elimination lamp, etc. are provided.The image carrier is uniformly charged by a charge corotron, and then an electrostatic latent image is formed on the image carrier by an exposure device. After the latent image is developed into a toner image by a developing device, the toner image is transferred to a transfer material by a transfer corotron, and a residual toner on the image carrier is removed by a cleaning device. Image formation is performed by a series of processes of removing charges on the body.

In the above-described image forming apparatus, there is a method in which an endless belt transport device is used for an image carrier, a transfer material transporter, an intermediate transfer member, a continuous paper transporter, and the like.

In this endless belt conveying device, the endless belt is stretched and driven by a plurality of rolls having at least a driving roll (driving rotating body) and a tension applying roll (tension applying rotating body). A phenomenon in which the belt moves in a direction perpendicular to the transport direction, that is, a meandering phenomenon occurs due to the parallelism between the rolls due to the arrangement, the cylindrical accuracy (shape accuracy) of the rolls, and the difference in the circumferential length between both ends of the belt. May be.

When this meandering phenomenon occurs, there is a problem that an image formed on the belt or an image transferred onto the belt is biased, so that a good image cannot be obtained.

A conventional system for solving this problem will be described with reference to FIG.

In FIG. 6, a roll shaft 107 is rotatably supported by bearings 108 and 109, and a belt 101 is stretched on a roll 104. Ribs 102 and 103 are formed at both ends of the belt 101 to be in contact with both ends 105 and 106 of the roll 104.
Thus, meandering of the belt 101 is restricted.

The belt 101 is driven by contact with a certain load F via the ribs 102 and 103. If there is a circumferential difference between both ends 105 and 106 of the belt 101, or if there is an axial alignment between the rolls. If not, rib 102,
As the load applied to the belt 103 increases and decreases, the belt 101
04 meanders in the axial direction J, and the belt 101
The load is applied until the vehicle slips. Since this load is extremely large, the ribs 102 and 103 wear out in a short period of time, which hinders belt control.

In order to reduce the load F and prevent the abrasion of the ribs, attempts have been made to improve the axial alignment between the rolls, the accuracy of the roll cylinders, and the accuracy of the circumference difference between both ends of the belt.

[0010]

However, when the degree of parallelism between the rolls, the accuracy of the roll cylinders, and the difference in the circumferential length between both ends of the belt change, the axial direction of the belt ribs must be minimized in order to minimize the durable damage to the belt ribs. Adjustment of the belt approaching force was necessary. For this purpose, it is necessary to adjust the tilt of the mounting alignment of the roll 104 at the time of assembling the apparatus or exchanging the belt and the roll, and the workability is not good.

Therefore, an object of the present invention is to provide a simple configuration,
It is an object of the present invention to provide an endless belt conveying device capable of suppressing meandering of the endless belt and minimizing damage to ribs of the endless belt.

[0012]

The above object is achieved by an endless belt conveying device according to the present invention. In summary, the present invention relates to an endless belt conveying device that stretches and drives an endless belt around a plurality of rotating bodies including at least a driving rotating body and a tension applying rotating body, wherein the endless belt is at least one end of the rotating body contact surface. At least one of the plurality of rotating bodies is formed of an elastic member, and a large number of slit portions and disk portions formed in a surface thereof in a radial direction, and at least an axial direction corresponding to the rib. An endless belt conveying device comprising: a rib guide member provided at an end.

The rib guide member elastically supports an end of the rib, and its deformation force is greater than the axial biasing force of the endless belt, and its spring constant is greater than that of the endless belt in the axial direction. Preferably, it is small. Preferably, the rib guide member is formed of an elastic body, and is fixed to an axial end of the rotating body. Preferably, the rib guide member is formed of a rigid body, and is elastically supported by an urging member at an axial end of the rotating body.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an endless belt conveying device according to the present invention will be described in more detail with reference to the drawings. In the following embodiment, the case where the present invention is applied to the transfer material conveying belt shown in FIG. 3 will be described. However, the present invention is not limited thereto.
Alternatively, the present invention can be applied to a monochrome image forming apparatus.

Embodiment 1 A first embodiment of the present invention will be described with reference to FIGS. First, the color image forming apparatus of this embodiment is shown in FIG.
This will be described below.

In FIG. 3, four image forming units M, C, Y, and Bk for magenta, yellow for cyan, and black are arranged opposite to the upper surface of the transfer belt 11 for transfer.

Each of the image forming units M, C, Y, and Bk is
An image carrier 16 composed of a photosensitive drum, a primary charger 17,
Latent image writing means 18, developing device 19, transfer charger 20,
The image carrier 16 is rotated in a direction indicated by an arrow in the figure.

A fixing unit 25 is provided downstream of the last image forming unit Bk.

The endless belt conveying device of the present embodiment mainly comprises
Transfer material transport belt (hereinafter simply referred to as "transport belt")
11 and a plurality of rolls (rotating bodies) 12, 13, 14, 1
And 5. More specifically, the transport belt 11 is an endless belt coated with a dielectric film, and includes at least a driving roll (driving rotating body) 1.
2, a plurality of rolls 1 including a tension applying roll (tension applying rotating body) 15 and a deviation correcting roll (deviation correcting rotating body) 14
It is stretched around 2, 13, 14, and 15 and is turned in the direction of arrow A in the figure.

A transport belt static eliminator 26 and a cleaning blade 27 are disposed downstream of the drive roll 12 in the moving direction of the transport belt 11.

The transfer material in the paper feed tray (not shown) is conveyed to the transfer material transport belt 11 by the feed roll 29 and then is attracted to the transfer material transport belt 11.

In the above-described color image forming apparatus, the image carrier 16 is uniformly charged by the primary charger 17, the image exposure corresponding to the original is performed by the latent image writing means 18, and the image carrier 16 is placed on the image carrier 16. An electrostatic latent image is formed. The electrostatic latent image is visualized as a toner image by attaching toner in the developing device 19.

The toner image is transferred to a transfer material on a transfer material transport belt 11 by a transfer charger 20. After the transfer, the toner remaining on the image carrier 16 is scraped off by a cleaner 21 to form a series of toner images. An image forming cycle is performed. This cycle is performed by four image forming units M, C,
The process is performed in Y and Bk, and a plurality of toner images are sequentially superimposed and transferred onto the transfer material sucked and transported by the transfer material transport belt 11.

Next, the endless belt conveying device of this embodiment will be described with reference to FIGS.

First, the deviation correction roll 14 of the present embodiment will be described. The deviation correction roll 14 is formed of an elastic member, and as shown in FIG. The portion 6 and the slit portion 8 are arranged in a ring shape and are juxtaposed in the axial direction, and rigid flanges 4a and 4b are provided at both ends.

The roll shafts 3a, 3b are mounted on the flanges 4a, 4b.
b is extended in the longitudinal direction of the deviation correction roll 14,
Each of the roll shafts 3a, 3b is supported by frames 1a, 1b via bearings 2a, 2b.

The conveyor belt 11 has belt ribs 5a and 5b on both sides of the roll contact surface. The belt ribs 5a and 5b are bonded to the conveyor belt 11 in advance with a parallelism of 0.2 mm or less using an adhesive jig. When the conveyor belt 11 moves in the direction of arrow A or B, the flange 4a , 4b to restrict the meandering of the conveyor belt 11.

FIG. 2 shows a state in which one of the belt ribs 5b is in contact with the flange 4b to restrict the deviation. When the conveyance belt 11 moves further in the direction of arrow A, a load F is applied to the flange 4b, and a return force G acts on the conveyance belt 11 in the direction of arrow B as a reaction, and the contact pressure of the contact surface 7 increases. However, since the outer portion 6a of the disk portion 6 is displaced in the axial direction as shown in the figure, the conveyor belt 11 is returned in the direction of the arrow B, and as a result, the contact pressure on the contact surface 7 decreases, and the flanges 4a, 4b Belt ribs 5a, 5
b can be prevented from being damaged by abrasion.

Therefore, once the state shown in FIG. 2 is reached, the conveyance belt 11 shifts in the axial direction (so-called D
The C walk does not proceed, and the meandering (so-called AC walk) does not proceed with the adhesion accuracy of the belt ribs 5a and 5b (parallelism of 0.2
mm or less). Also, the belt ribs 5a, 5b
By lowering the surface pressure, the durability also increases.

Embodiment 2 Next, a second embodiment according to the present invention will be described with reference to FIG. The endless belt conveying device of the present embodiment has a configuration substantially similar to that of the belt conveying device of the first embodiment.
While the flanges 4a and 4b of the shift correction roll 14 of the embodiment are formed of a rigid body, the flange 9 of the embodiment is
a and 9b are elastic flanges formed of elastic members.

As shown in FIG. 4, when the belt rib 5b of the conveyor belt 11 comes into contact with the elastic flange 9b, the elastic flange 9b is deformed in the direction of arrow H, and the belt rib 5a becomes Δx.
Move in the axial direction.

Here, the axial spring constant of the elastic flanges 9a and 9b is K2, the limit deformation amount in the axial direction is w, and the axial spring constant of the disk group of the deviation correcting roll 14 is K1.
(Theoretical value or actual measured value modeled on the deflection of the beam), and if the belt deviating force generated by the alignment difference or the belt circumferential length difference is F, this system can prevent the deviating under the following conditions.

F <K2 · w... Further, assuming that the meandering amount X of the belt rib with respect to the conveying belt and the moving amount Y of the conveying belt 11 caused by the limit of the adhesion accuracy of the belt rib are, the equilibrium condition at the contact point 7 is as follows. Is as follows:

Y = X · K2 / K1 ... Elastic flanges 9a, 9b if K2 / K1 is set to the minimum
Can absorb the meandering amount X, and can minimize Y.

However, in order to suppress belt wear,
In order to reduce the deviation force F itself, it is better to reduce K1 to some extent.

As described above, by setting K1 and K2 so as to satisfy the conditions (1) to (4), it is possible to further reduce the movement amount of the transport belt as compared with the first embodiment.

Embodiment 3 Next, a third embodiment of the present invention will be described with reference to FIG.

In this embodiment, in a configuration substantially similar to that of the second embodiment, a backup spring 31 as an urging member is provided between the flange 30 of the deviation correction roll 14 and the outermost disk portion 6m. The configuration is such that it is biased toward the belt rib 5b. At this time, the backup spring 31
Is K2, and the others are the same as in the second embodiment.

Also in the present embodiment, the amount of movement of the conveyor belt 11 is smaller than in the first embodiment, and more accurate belt control is possible. Therefore, it is also effective in preventing color shift between the image forming units M, C, Y, and Bk shown in FIG.

[0040]

As is apparent from the above description, according to the present invention, the endless belt has a rib on at least one end of the rotating body contact surface, the rotating body is formed from an elastic member, and the surface has a radius. With a large number of slits and discs formed in the direction and a rib guide member provided at least at an axial end corresponding to the rib, a meandering phenomenon of the endless belt can be suppressed with a simple configuration. In addition, damage to the ribs of the endless belt can be minimized, so that the transfer performance of the endless belt transfer device can be improved and the service life can be extended.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a main part of an endless belt conveying device according to a first embodiment of the present invention.

FIG. 2 is an explanatory view of a main part showing a state in which the endless belt is shifted in the endless belt transport device of FIG.

FIG. 3 is a schematic configuration diagram illustrating a color image forming apparatus according to a first embodiment.

FIG. 4 is a cross-sectional view illustrating a main part of an endless belt conveying device according to a second embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating a main part of an endless belt conveying device according to a third embodiment of the present invention.

FIG. 6 is an explanatory diagram showing an example of a conventional endless belt transport device.

[Explanation of symbols]

 4a, 4b Flange (rib guide member) 5a, 5b Rib 6 Disc 8 Slit 11 Endless belt 12 Driving roll (driving rotating body) 14 Deviation correcting roll (deviation correcting rotating body) 15 Tension applying roll (Tension applying rotating body)

Claims (4)

[Claims] 1. An endless belt transporting apparatus that stretches and drives an endless belt around a plurality of rotating bodies including at least a driving rotating body and a tension applying rotating body, wherein the endless belt has a rib on at least one end of the rotating body contact surface. At least one of the plurality of rotating bodies is formed of an elastic member, and has a large number of slits and discs formed in a surface thereof in a radial direction, and at least an axial end corresponding to the rib. An endless belt conveying device, comprising: a provided rib guide member. 2. The rib guide member elastically supports an end portion of the rib, a deformation force of the rib guide member is larger than an axial biasing force of the endless belt, and a spring constant of the rib guide member is an axial spring of the endless belt. 2. The method according to claim 1, wherein the value is smaller than a constant.
Endless belt conveyor. 3. The rib guide member is formed of an elastic body,
3. The endless belt conveying device according to claim 2, wherein the endless belt conveying device is fixed to an axial end of the rotating body. 4. The endless belt conveying device according to claim 2, wherein the rib guide member is formed of a rigid body, and is elastically supported by an urging member at an axial end of the rotating body.