JPH04189234A - Belt driving device - Google Patents

Abstract

PURPOSE:To correct snaking of a belt automatically and securely by making a belt contact surface of a roller member with taper parts of elastic body, in which short fiber is included and the short fiber is exposed in the surface. CONSTITUTION:A belt contact surface of a snaking adjusting roller member 3 is made of an elastic body 36, in which short fiber is included. A coefficient of friction with a flat belt 4 is therefore small, and the movement of the flat belt 4 in the thrust direction is facilitated. Furthermore, a coefficient of friction with the flat belt 4 is small, and when the end of the flat belt 4 rides on taper parts 34 of the roller member 3, the tensile force of this end side is increased, and the flat belt 4 is moved to the direction opposite to the snaking direction, and snaking of the flat belt 4 is corrected automatically.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a drive device for a flat belt, particularly 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 photoconductor belt or a transfer conveyance belt instead of a photoconductor drum.

However, flat belts used for such purposes are often made of a material with low elongation and high strength, such as a plastic film or metal foil, as a base material. Therefore,
Since this type of flat belt is difficult to deform elastically, it is possible to absorb 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, high precision and high resolution are required in order to perform accurate image formation, so it is necessary to prevent the flat belt from meandering.

As a conventional technique for preventing such belt meandering, a guide for preventing meandering is provided on the belt as shown in Japanese Patent Laid-Open No. 127501/1982 and Japanese Patent Laid-open No. 205052/1983. , Japanese Patent Publication No. 57-6034
As shown in Japanese Patent No. 7, it has been proposed to forcibly prevent meandering of the flat belt by providing a regulating member. Also,
Utility Model Application Publication No. 58-110609 and Utility Model Application No. 64-484
As shown in Japanese Patent No. 57, 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 by an external member, it may not be possible to establish the mechanism depending on the conditions of the combination of the flat belt and the roller member. . That is, as the shifting force associated with meandering of the flat belt 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 of 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 Japanese Patent No. 48457 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 device as a whole, but also requires a complicated mechanism to correct the meandering. As the number of points is large, the number of failure-causing factors increases accordingly, and it is difficult to say that the reliability of the device is sufficiently ensured.

On the other hand, in belt drive devices with two axes and three or more axes, if there is an error in the installation of the belt and roller members, the direction and magnitude of the acting force on the belt will differ for each roller member, and the belt will The parts were slipping.

As a result, if the coefficient of friction between the belt and the roller member causing this slippage is large, the belt or roller member may
There was a problem with i.

Also, if the coefficient of friction between each roller member and the belt is small,
In order to run the belt accurately, it is necessary to increase the belt tension, and there is a problem in that the durability of the belt is poor.

Furthermore, in a belt drive device that combines a film-like belt and a roller member with a smooth surface, since the belt surface and the roller member surface are in close contact, the frictional force between the two is determined by the interfacial state. Become.

Since this interface state is greatly affected by temperature and humidity, the frictional force changes greatly depending on temperature and humidity. Therefore, it has been considered to form irregularities on the belt contacting surface of the roller member, but this has the problem that increasing the transmission capacity also increases the thrust force, causing damage to the belt.

The present invention has been made in view of these points, and prevents damage etc. without performing complicated processing on roller members and flat belts, and has a simple mechanism and a small space.
It is an object of the present invention to provide a heddle drive device that can inexpensively prevent meandering of a belt.

(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 an elastic body containing short fibers to facilitate movement of the flat belt in the thrust direction and to correct meandering of the flat belt.

Specifically, the measures taken by the invention according to claim (1) are: first, a belt drive comprising a flat belt and a plurality of roller members around which the flat belt runs, and on which the flat belt runs; equipment is assumed.

At least one roller member among the plurality of roller members has both ends pulled in a predetermined action direction in which tension is applied to the flat belt by the roller support member, and both ends are moved in the action direction. The meandering adjustment roller member is configured to be freely supported. Further, at least one of the plurality of roller members is formed with a tapered portion that becomes larger in diameter toward the outside. In addition,
The belt contacting surface of the tapered roller member is made of an elastic body that contains short fibers and exposes the short fibers on the surface.

Further, in the belt drive device according to claim (1), the means taken by the invention according to claim (2) is such that the short fibers are oriented at a predetermined angle with respect to the radial direction of the roller member, The means taken by the invention according to 3) is such that the short fibers are aramid fibers.

Further, in the belt drive device according to any one of the above claims (1) to (3), the means taken by the invention according to claim (4) is that the flat belt is a photoreceptor belt or a transfer conveyance belt. It is structured as follows.

(Function) With the above configuration, in the inventions according to claims (1) to (3), the flat belt runs between the plurality of roller members due to the rotation of the drive-side roller member. In particular, in the invention according to claim (4), the photoreceptor belt or the transfer conveyance belt runs. When the flat belt meanderes, at least one roller member is formed as a meandering adjustment roller member with a chi, so it rides on the side end or tapered part of the flat belt.

On the other hand, since the belt contact surface of the meandering adjustment roller member is made of an elastic body containing short fibers, the coefficient of friction with the flat belt is small, and the flat belt can easily move in the thrust direction. The coefficient of friction with the belt is small, and when the end of the flat belt rides on the tapered part, the tension on the end side increases, the flat belt moves in the opposite direction to the meandering direction, and the meandering direction of the flat belt automatically stops. will be corrected.

(Effects of the Invention) Therefore, according to the invention according to claims (1) to (4), the meandering adjustment roller member is configured, and the belt contacting surface of the roller member is configured of an elastic body containing short fibers. Since the tapered portion is formed in the roller member, when the flat belt meanderes, the tension at the end of the flat belt on the meandering side increases, and since the coefficient of friction against the roller member is small, the meandering can be automatically and reliably corrected. This makes it possible to run the flat belt stably, especially when applied to electrophotographic equipment.
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 friction coefficient in the thrust direction is reduced in the roller member with the tapered portion, meandering can be corrected by reducing the amount of displacement, that is, the amount of twist, of the roller member, and damage due to slipping can be prevented. As a result, the life of the belt can be extended.

Furthermore, since the frictional force is less affected by the interface state between the flat belt and the roller member, that is, by temperature and humidity, environmental stability can be improved. Furthermore, since the belt includes a needle-shaped body, a gripping force is applied, and high transmission capacity can be achieved with a small belt tension.

In addition, if the short fibers in the tapered part are oriented toward the small diameter side,
The flat belt is less likely to meander toward the larger diameter side and more easily moves toward the smaller diameter side, making it possible to reduce meandering and quickly correct the meandering.

On the other hand, since the short fibers are aramid fibers, the short fibers can be exposed reliably.

(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 M1 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 apparatus. are doing.

Further, as the base material of the photoreceptor belt 4, for example, 2
Axially oriented polyester is used, and the tensile modulus is 2.
00 kg/as 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 also 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, 34 are connected to both ends of the parallel part 33. It is formed in the shape of Further, as a feature of the present invention, the belt contact surfaces, which are the surfaces of the parallel portion 33 and the tapered portion 34, are composed of an elastic body 36 containing short fibers 35. In addition to the rubber composition, this elastic body 36 is made of
It is made of thermoplastic elastomer, etc. On the other hand, the short fibers 35 are PET.

Organic fibers such as nylon, aramid, cotton, and cellulose,
No carbon fiber! In addition to a-fibers, it is composed of inorganic acicular fillers such as silicon carbide, iron oxide, and titanate. Further, the short fibers 35 are formed to have a length of 1 to 10+an, are exposed on the surface of the elastic body 36, and are oriented in the radial direction of the roller member 30 (Z orientation).
has been done. Furthermore, for example, the short fibers 35 are oriented almost perpendicularly to the surface of the elastic body 36 in the parallel portion 33, and are oriented in a direction slightly inclined toward the small diameter side (inside) in the tapered portions 34, 34. There is. The elastic body 36 reduces the coefficient of friction with respect to the photoreceptor belt 4 to reduce the thrust force and provides a predetermined gripping force.

Further, the tapered portion 34 is configured such that when the photoreceptor belt 4 meanderes, the belt end 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 made up of materials. 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 driven roller member 3 is configured as a meandering adjustment roller member by movably supporting the end portion of the roller member. Further, the bearing 51 is rotatably fitted onto the driven shaft 32, and
The spring 52 has one end attached to a fixed member,
A driven shaft 32 is used to apply tension to the photoreceptor belt 4.
is pulled in the direction of tension, that is, 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 ω)j roller member 2 rotates and the photoreceptor belt 4 or both ends -
It runs between the rubber members 2 and 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 entry 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 moved toward the driven shaft by the spring force of the spring 52. 32 is stretched, 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 belt contact surface, which is the surface of the parallel portion 33 and the tapered portion 34, is composed of the short fiber-containing elastic body 36, which has a small coefficient of friction and a small thrust force, and furthermore, the short fibers 35 are oriented inward. , the photoreceptor belt 4 reliably moves in the opposite direction to the meandering direction, and the meandering is corrected.

Further, since the short fiber-containing elastic body 36 is used, the driven roller member 3 maintains a high transmission ability with a small belt tension.

Here, to describe in detail a specific example of the elastic body 36 in the driven roller member 3, the short fibers 35 are aramid fibers, the length is 1 to 61 DI11, the fiber diameter is lam or less,
Preferably it is 1 to 100 μm, and chloroprene rubber 8
Short fiber 35 is blended at 20% by volume compared to 0% by volume.

Next, to explain the manufacturing process of the driven roller member 3, first, as shown in FIG. 3(a), short fibers 35
An unvulcanized rubber sheet 36a is formed in which the rubber is oriented in the thickness direction. On the other hand, as shown in FIG. 3(b), a roller base material 3a having a tapered portion is formed, and the rubber sheet 36a is wound around this roller base material 3a so as not to disturb the orientation of the short fibers 35. The driven roller member 3 is obtained by vulcanizing and polishing the surface by puffing or the like to expose the short fibers 35.

Further, as shown in FIG. 4, the short fibers 3 of the tapered member 34
If the direction of orientation of rubber sheet 5 is slightly inward, the rubber sheet 3
6a is formed separately into a parallel portion 33 and a tapered portion 34, and is wound around the roller base material 3a.

Therefore, the tapered portions 34 and 35 of the driven roller member 3 are
, and the belt contact surface is constituted by the short fiber-containing elastic body 36, so when the photoreceptor belt 4 meanders, the tension at the end of the belt on the meandering side increases, and the coefficient of friction against the driven roller member 3 increases. Since it is small, meandering can be corrected automatically and reliably, and the photoreceptor belt 4 can be run stably, and especially when applied to an electrophotographic device, 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.

Furthermore, since the friction coefficient in the thrust direction of the driven roller member 3 is reduced, it is possible to correct meandering by reducing the amount of displacement, that is, the amount of twist, of the roller member 3, and to prevent damage due to slipping. Since this can be prevented, the life of the belt can be extended. Furthermore, since the frictional force is less affected by the interface state between the photoreceptor belt 4 and the driven roller member 3, that is, by temperature and humidity, environmental stability can be improved.

Furthermore, since it is formed of the short fiber-containing elastic body 36, it has a gripping force for the photoreceptor belt 4, so that high transmission capacity can be achieved without increasing the belt tension.

Furthermore, when the short fibers 35 in the tapered portions 34, 34 are oriented toward the small diameter side (parallel portion 33 side), the photoreceptor belt 4 becomes difficult to meander outward, and at the same time, can easily move inward. The amount of meandering can be reduced and the meandering can be quickly corrected.

On the other hand, when the above-mentioned type 1a fiber 35 is made of aramid fiber, it has good heat resistance, so it is possible to prevent it from coming off during processing, and it is possible to reliably expose the photoreceptor belt 4 from the elastic body 36. can improve the slippage.

FIG. 5 shows another driven roller member 3b, which is formed from two gently curved tapered portions 34a, 34a, and is formed into an inverted crown shape. The elastic body 36 and the like are the same as in the previous embodiment.

Although this embodiment has been described with respect to an electrophotographic apparatus, the present invention may be applied to various apparatuses such as a transfer conveyance apparatus, in which case the flat belt constitutes a transfer conveyance belt.

Further, in this embodiment, one driven roller member 3 is provided, but a plurality of driven roller members 3 may be provided.
At least one roller member may be provided with a roller member having a tapered portion, and the roller member with a tapered portion and the meandering adjustment roller member may be separate.

In addition, the above-mentioned flat belt is made of metal thin plates such as nickel and stainless steel, as well as PET, PES, and PEEK.

It may be formed from a plastic film such as aramid or polyimide, or may be a seamless heald or jointed belt.

Furthermore, the drive-side roller member 2 is not limited to the elastic roller 21.

Further, the short fibers 35 may be oriented in a direction slightly inclined to the longitudinal direction of the roller member 3.

[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. 3(a) and (b) are perspective views of a rubber sheet and a driven roller member showing the manufacturing process of the driven roller member, and FIG. 4 is a perspective view of the driven roller member showing another manufacturing process. . FIG. 5 is a front view showing another driven roller member. 1... Belt drive device 2... Drive side roller member 3.3b... Driven side roller member (meandering adjustment roller member) 4... Photoreceptor belt (flat belt) 5... Roller support member 33 ...Parallel part 34.34a...Tapered part 35...Short fiber 36...Elastic body 52...Spring and 1 other person

Claims (4)

[Claims] (1) In a belt drive device comprising a flat belt and a plurality of roller members around which the flat belt runs and the flat belt runs, at least one roller member among the plurality of roller members. is constituted by a meandering adjustment roller member in which both ends are pulled in a predetermined action direction in which tension is applied to the flat belt by a roller support member, and both ends are supported movably in the action direction, and the plurality of At least one roller member of the roller members is formed with a tapered portion that becomes larger in diameter toward the outside, and the belt contacting surface of the roller member with the tapered portion contains short fibers and the short fibers. A belt drive device comprising an elastic body with fibers exposed on the surface. (2) The belt drive device according to claim (1), wherein the short fibers are oriented at a predetermined angle with respect to the radial direction of the roller member. (3) The belt drive device according to claim (1) or (2), wherein the short fibers are aramid fibers. (4) The belt drive device according to claim (1), (2) or (3), wherein the flat belt is a photoreceptor belt or a transfer conveyance belt.