JPH04133933A - Belt driving device - Google Patents

Abstract

PURPOSE:To facilitate the amendment of meandering by providing tapered parts enlarging in a diameter toward their outsides on both the ends of a driven roller member engaged over with a flat belt, and forming the surface of a belt contact face between both the tapered members of the roller member of fiber compound elastomer. CONSTITUTION:Both the ends of a driven roller member 3 engaged over with a flat belt 4 are provided with tapered parts 34 enlarging in a diameter toward their outsides to prevent the meandering of the belt 4. A roller part 33 between tapered parts 34 is formed into the parallel part of a cylindrical body having uniform diameter, whose surface, namely a belt contacting face, is formed of elastomer made of composite organic short fiber, and the organic short fiber is exposed on the surface of the belt contact face, whose coefficient of friction against the belt 4 therefore becomes small. The belt 4 meanders to run-on to the tapered part 34, and the meandering is thereby amended, and in this case, the lateral movement of the belt 4 during the amending of its meandering is simplified because the coefficient of friction on the parallel part 33 is low, and the amendment of meandering therefore becomes easy.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a drive device for a flat belt, and particularly to a belt drive device for a photoreceptor belt, a transfer conveyance belt, etc. of a device using an electrophotographic method. .

(Prior Art) Conventionally, for example, in an electrophotographic apparatus, for the purpose of making the apparatus lighter and more compact, a plurality of roller members arranged substantially parallel to each other have a surface formed with a photosensitive layer or a dielectric layer. It is known to span a flat belt and use the flat belt as a photoreceptor belt or a transfer conveyance belt in place of a photoreceptor drum.

However, flat belts used for such purposes are often formed from a material with low elongation and high strength, such as a plastic film or metal foil, as a base material. Therefore,
This type of flat belt is difficult to elastically deform, so it absorbs dimensional errors in related parts, installation errors in roller members, unbalanced belt tension, uneven belt circumference, etc. by deforming the belt itself. As a result, there is a problem in that meandering tends to occur when the flat belt runs.

However, in such an electrophotographic apparatus, surface accuracy and high resolution are required in order to form accurate images, so it is necessary to prevent the flat belt from meandering.

As a conventional technique for preventing such meandering of the belt, the Bell I-
A guide was installed to prevent meandering, and
As shown in Japanese Patent No. 47, it has been proposed to forcibly prevent meandering of the flat belt by providing a regulating member. Also, Utility Model Application No. 58-110609 and Utility Model Application No. 64-4
As shown in Japanese Patent No. 8457, there are some devices that use a complicated mechanism structure to correct meandering.

(Problem to be solved by the invention) However, JP-A-56-127501, JP-A-59-205052 and JP-A-57-6034
In the configuration shown in Publication No. 7, since the flat belt is forcibly stopped from being supported by an external part, there are cases where the mechanism cannot be realized depending on the conditions of the combination of the flat belt and the roller member. be. That is, as the shifting force due to the flat belt's serpentine jF increases, it is necessary to increase the strength of the guide and the regulating member. Furthermore, it is necessary to increase the buckling strength in the width direction of the flat belt itself, and at the same time, it is necessary to increase the strength at the end portions of the flat belt so that the end portions are not damaged.

Therefore, the thinner the belt becomes, the more difficult it becomes to employ the above method. Further, when providing a guide on a flat belt, it is necessary to provide the guide with high precision, and particularly in the case of a seamless belt, it is extremely difficult to form the guide itself.

Also, Utility Model Application Publication No. 58-110609, Utility Model Application No. 64-
The method disclosed in Publication No. 484.57 uses a complicated mechanism to correct the meandering, which is expensive and requires extra space, which not only leads to an increase in the size of the entire device. As the number of parts in the mechanism is large, the number of failure-causing parts increases accordingly, and it is difficult to say that the reliability of the device is sufficiently ensured.

The present invention has been made in view of the above, and it is possible to prevent belt meandering at low cost using a simple mechanism and in a very small space without performing complicated processing on the roller member or flat belt. The purpose is to provide a belt drive device that can.

(Means for Solving the Problems) In order to achieve the above object, the means taken by the present invention are as follows:
The roller member is made of fiber composite elastomer to facilitate the movement of the belt in the thrust direction, and the meandering of the flat belt is corrected by tapered portions at both ends of the roller member.

Specifically, the measures taken by the invention according to claim (1) include firstly providing a flat belt and a plurality of roller members around which the flat belt is stretched and on which the belt runs. . Taper portions are formed at both ends of at least one driven roller member among the roller members and have a larger diameter toward the outside. In addition, the belt contact surface between both tapered parts in the tapered roller member is made of a fiber composite elastomer with organic fibers exposed on the surface.

(Function) With the above configuration, in the invention according to claim (1), the flat belt travels between the plurality of roller members due to the rotation of the drive-side roller member. When the flat belt meanderes, the tapered portions are formed at both ends of at least one driven roller member, so the side ends of the flat belt ride on the tapered portions.

On the other hand, since the belt contact surface of the tapered roller member is made of fiber composite elastomer, the flat belt can easily move in the thrust direction. The belt moves in the opposite direction to the meandering direction, and the meandering of the flat belt is automatically corrected.

(Effect of the Invention) Therefore, according to the invention according to claim (1), the belt contacting surface of the roller member with a tapered portion is made of a fiber composite elastomer, and the tapered portion is formed at the end of the roller member. Furthermore, when the flat belt meanderes, the coefficient of friction on the meandering side with respect to the roller member decreases. As a result, the meandering is automatically and reliably corrected, so that the flat belt can run stably, and particularly when applied to an electrophotographic apparatus, reliable image formation can be performed.

Further, since a guide member and the like are not provided as in the conventional belt, the flat belt is not damaged and its life can be extended. Furthermore, since meandering can be corrected with a simple configuration, it can be applied to various devices.

In addition, since the driven roller member is made of fiber composite elastomer, the friction coefficient of the driving roller member is increased, making it easier for the flat belt to slip on the driven roller member, reducing the driving force and ensuring reliability. belt transmission.

In addition, in the roller member with the tapered portion, the coefficient of friction in the thrust direction is reduced, so meandering can be easily corrected, and the frictional force is less affected by the interface state between the flat belt and the roller member. Therefore, environmental stability can be improved.

Furthermore, since it is made of fiber composite elastomer, it is difficult for foreign matter to get mixed in between the flat belt and the roller member, and damage to the belt can be prevented.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

As shown in FIG. 1, reference numeral 1 denotes a belt drive device, which is provided in an electrophotographic apparatus. The belt drive device 1 is configured such that a photoreceptor belt 4 is stretched between a driving roller member 2 and a driven roller member 3.

The photoreceptor belt 4 is composed of a wide flat belt, and although not shown, a photoreceptor layer is laminated on the surface of a base material, and the photoreceptor belt 4 functions as a photoreceptor in an electrophotographic device. are doing.

Further, as the part shrine of the photoreceptor belt 4, for example, 2
Axially oriented polyester is used, and the bow tensile modulus is 2.
00 kg/n+m 2 or more.

The drive-side roller member 2 is composed of a large-diameter elastic roller 21 and a small-diameter drive shaft 22 fitted and fixed thereto. Although not shown, both ends are rotatably supported by a fixed member.

A drive motor 23 is linked to one end of the drive shaft 22.

On the other hand, the driven roller member 3 is a roller member that is a feature of the present invention, and is constructed by fitting and fixing a small-diameter driven shaft 32 into a large-diameter roller main body 31, as shown in FIG. ing. The roller main body 31 is made up of a parallel part 33 which is a perfect circle with an approximately uniform diameter, and tapered parts 34 and 34 are connected to both ends of the parallel part 33, and the belt contact surface which is the surface of the parallel part 33 is It is composed of a fiber composite elastomer 35 having the following characteristics. The fiber composite elastomer 35 is an elastomer made by combining organic short fibers such as polyester fibers and aramid fibers, and is formed with the organic short fibers exposed on the surface so that the coefficient of friction against the photoreceptor belt 4 is small. It is configured.

Further, the tapered portion 34 is formed in a tapered shape with a diameter increasing outward on both the left and right sides, and has a friction coefficient set to be larger than the friction coefficient of the belt contact surface made of the fiber composite elastomer 35. When the photoreceptor belt 47 meanders, the end portion of the belt rides on the tapered portion 34 to correct the meandering.

On the other hand, both ends of the driven shaft 32 are connected to roller support members 5.5 and 5.5.
The roller support member 5 includes a bearing 51, a spring 52 attached to the bearing 51, and, although not shown, a fixed support having a long hole or the like into which the driven shaft 32 is inserted. It is constructed with a shrine. The roller support member 5 is connected to the driven shaft 32 in the direction in which tension is applied to the photoreceptor belt 4, that is, in the direction in which the driven roller member 3 approaches and separates from the drive roller member 2.
The end of the frame is movably supported. Furthermore, the bearing 51
is rotatably fitted around the driven shaft 32, and the spring 52 has one end attached to a fixed member, and the driven shaft 32 is rotated in the direction of tension so as to apply tension to the photoreceptor belt 4. In other words, it is arched in the direction away from the drive-side roller member 2.

Next, the operation of the belt drive device 1 will be explained together with the meandering correction operation.

First, in a state in which the photoreceptor belt 4 is stretched around both roller members 2 and 3, the driven roller member 3 is attached to the spring 5.
2.52 in the direction away from the drive-side roller member 2, a predetermined tension is applied to the photoreceptor belt 4.

In this state, when the drive motor 23 is driven, the drive-side roller member 2 rotates and the photoreceptor belt 4 runs between both roller members 2.3.

While the photoreceptor belt 4 is running, if the photoreceptor belt 4 meanders, for example, in the direction A in FIG.
The end of the photoreceptor belt 4 on the A direction side rides on the tapered portion 34 . The end of the driven roller member 3 on the A direction side is slightly displaced in the direction approaching the driving roller member 2, while the end of the photoreceptor belt 4 on the A direction side is driven by the spring force of the spring 52. axis 32
Since it is being stretched, a certain amount of tension is applied to the photoreceptor belt 4, and a force is generated in the photoreceptor belt 4 in the opposite direction to the meandering direction (opposite to the direction A), thereby correcting the meandering.

In particular, the coefficient of friction of the tapered part 34 is larger than the coefficient of friction of the fiber composite elastomer 35 of the parallel part 33, and moreover, the fiber composite elastomer 35 allows the displacement side part (A direction side part) of the parallel part 33 and the photoreceptor belt 4 to As a result, the friction coefficient between the photoreceptor belts 4 is reliably moved in the opposite direction to the meandering direction, and the meandering is corrected.

Therefore, since the parallel portion 33 of the driven roller member 3 is made of the fiber composite elastomer 35 and the tapered portion 34 is formed on the roller member 3, when the photoreceptor belt 4 meanders, the meandering relative to the driven roller member 3 occurs. The friction coefficient on the side will decrease. As a result, the meandering is automatically and reliably corrected, so that the photoreceptor belt 4 can run stably, and particularly when applied to an electrophotographic apparatus, reliable image formation can be performed.

In addition, since a guide member or the like is not provided as in the conventional case, the photoreceptor belt 4 is not damaged and its life can be extended. Furthermore, since meandering can be corrected with a simple configuration, it can be easily applied to electrophotographic apparatuses.

Further, since the driven roller member 3 is made of the fiber composite elastomer 35, the friction coefficient of the driving roller portion +42 becomes large, and the photoreceptor belt 4 easily slips on the driven roller portion I13. The driving force can be reduced and reliable belt transmission can be performed.

Further, in the driven roller member 3, the coefficient of friction in the direction of the thrust force is reduced, so the amount of displacement, that is, the amount of twist, of the roller member 3 can be reduced to correct the meandering, and the frictional force can be reduced. Since the state of the interface between the body belt 4 and the driven roller member 3 is less affected, environmental stability can be improved.

Further, since it is made of the fiber composite elastomer 35, it is difficult for foreign matter to get mixed in between the photoreceptor belt 4 and the driven roller member 3, and damage to the belt can be prevented.

Further, since the friction coefficient of the tapered portion 34 is large, the tension on the meandering side of the photoreceptor belt 4 is reliably increased, and the meandering can be reliably prevented.

Although this embodiment has been described with respect to an electrophotographic apparatus, the present invention may be applied to various scale devices such as a transfer conveyance device.

Further, in this embodiment, one driven roller member 3 is provided, but a plurality of driven roller members 3 may be provided. That's fine.

Furthermore, the drive-side roller member 2 is not limited to two elastic rollers.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is an overall perspective view of a belt drive device, and FIG. 2 is a front view of a driven roller member. 1... Belt drive device 2... Drive side roller member 3... Driven side roller member (roller member with a tapered part) 4... Photoreceptor belt (flat belt) 5... Roller support part shrine 33 ...S[1 row part 34...Tapered part 35...Fiber composite elastomer

Claims (1)

[Claims] (1) A flat belt, a plurality of roller members around which the flat belt is stretched and on which the flat belt runs, and a roller member formed at both ends of at least one driven roller member among the roller members and extending outwardly. and a tapered portion that becomes larger in diameter in the opposite direction, and the belt contact surface between both the tapered portions in the roller member with the tapered portion is made of a fiber composite elastomer with organic fibers exposed on the surface. Drive device.