JPH04159938A - Flat velt and driving device therefor - Google Patents

Abstract

PURPOSE:To maintain rigidity and reduce friction coefficient by composing the back layer of a flat belt composed of multiple laminated layers, of a resilient body in which short fibers are mixed in, disposing the short fibers in the circumferential direction of the belt such that they are inclined to the thickness direction thereof and exposed partially from the contact face with a roller. CONSTITUTION:A photosensitive belt 4 is formed of a tension layer 4a, a back layer 4b where short fibers F composed of a plurality of organic fibers are mixed in a resilient body made of rubber. The back layer 4b is formed to protrude in the belt width direction at the both edges. The short fibers F in the back layer 4b are arranged to be inclined little to the circumferential direction of the belt 4 to the belt thickness direction from the direction parallel to the surface of the belt 4, and formed such that a part thereof is exposed from the contact face of the back layer 4b to a roller 2. It is thus possible to reduce the frictional coefficient with respect to the roller 2 under the conditions that the rigidity of the back layer 34b is maintained.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a photoreceptor belt in the field of electrophotography.

The present invention relates to flat belts that require precision driving, such as transfer conveyance belts, and their driving devices.

(Prior Art) Conventionally, for example, in an electrophotographic device, a photoreceptor layer or a dielectric layer is formed on the surface of a plurality of roller members arranged approximately parallel to each other in order to make the device lighter and more compact. It is known to pass a flat belt over a belt and use the flat belt as a photosensitive belt or a transfer conveyance belt in place of a photosensitive 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, such electrophotographic devices require high precision and high resolution in order to form accurate images.
It is necessary to prevent this flat belt from meandering.

As a conventional technique for preventing such meandering of the belt, a protrusion for preventing meandering is provided on the back side of the belt as shown in Japanese Patent Laid-Open No. 56-127501 and Japanese Patent Laid-Open No. 59-205052. On the other hand, a guide groove that engages with the protrusion is provided on the roll side, and
As shown in Japanese Patent No. 47, it has been proposed to forcibly prevent meandering of the flat belt by providing regulating members that come into contact with both ends of the belt and regulate the movement of the belt in the width direction. Also, Utility Model Application Publication No. 58-110609 and Utility Model Application No. 64-4
Some devices use a complicated mechanical structure to correct meandering, as shown in Japanese Patent No. 8457.

(Problems to be Solved by the Invention) However, each of the above conventional methods has the following problems.

That is, in the configurations shown in JP-A-56-127501 and JP-A-59-205052, the protrusions are provided on the belt, which increases the cost, and the protrusions make it difficult to manufacture the joint at the belt. It becomes necessary,
It is difficult to make a seamless belt. Furthermore, since the protrusions are easily damaged, there is a risk that reliability may be reduced.

Furthermore, Utility Model Application No. 58-110609, Utility Model Application No. 64
The method disclosed in Japanese Patent No. 48457 uses a complicated mechanism to correct meandering, which is expensive and requires extra space, which not only leads to an increase in the size of the entire device, but also requires a complicated mechanism. As the number of parts 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.

On the other hand, the configuration shown in Japanese Patent Application Laid-Open No. 57-60347 can suppress meandering of the belt with a simple configuration.
Problems like the ones mentioned above rarely occur. However, when a flat belt is forcibly restricted from the outside, a thin belt as described above is likely to be damaged in the circumferential direction of the belt or wrinkled. In particular, when the belt is made of a highly rigid material such as metal or plastic and is thin, there is a problem in that the regulating member is also susceptible to damage due to wear and the like. The same applies when a flange is provided on the roller instead of the member as in the above-mentioned publication as the regulating member.

Furthermore, as mentioned above, it was necessary to use a material with low elongation and high strength as the base material, but it was particularly difficult to seamlessly process such a material, leading to an increase in the cost of the apparatus.

The present invention has been made in view of these points, and its purpose is to improve the sliding characteristics of the flat belt by providing the flat belt with a back layer that has good cushioning properties and appropriate rigidity in the circumferential direction. The object of the present invention is to improve the running characteristics of the flat belt by maintaining appropriate rigidity and flexibility of the flat belt.

(Means for Solving the Problem) In order to achieve the above object, the solution of the present invention is to provide a flat belt with a back layer made of an elastic material mixed with short fibers, and to orient the short fibers in the circumferential direction of the belt. be.

Specifically, the means taken by the invention of claim (1) is to make the flat belt a laminate consisting of at least two layers, and to make the back layer of the two layers an elastic material mixed with a large number of short fibers. The short fibers are formed and the short fibers are oriented in the circumferential direction of the belt.

The means taken by the invention of claim (2) are the same as those of claim (1) above.
The short fibers in the described invention are oriented so as to be slightly inclined from a direction parallel to the belt surface toward the belt thickness direction, and a portion of the short fibers are exposed from the roller contact surface of the back layer.

The means taken by the invention of claim (3) are the same as those of claim (1) above.
Or the short fiber length in the invention described in (2) is 0.5 to
It is set to 10 mm.

The means taken by the invention of claim (4) are the same as those of claim (3) above.
The short fibers in the described invention have a length of 0.5 to 10111
11 aramid fibers.

The means taken by the invention of claim (5) are the same as those of claim (1) above.
.

(21, f31 or the invention described in (4), in which the thickness of the back layer is 100 μm or more.

The means taken by the invention of claim (6) is to provide a plurality of roller members, and claim +11. f2), (31, (4)
Alternatively, a flat belt drive device configured to drive the flat belt described in (5) by winding it around the plurality of roller members.

(Function) With the above configuration, in the invention of claim (1), since the flat belt is provided with the back layer made of an elastic material, the mounting tension required to drive the flat belt is reduced, and running becomes smooth. Damage to the flat belt is suppressed even when foreign matter such as toner or paper dust gets caught in the flat belt, and the belt thickness can be increased while maintaining appropriate belt rigidity and flexibility.

In particular, since the short fibers are oriented in the circumferential direction of the belt, the rigidity of the belt as a whole is improved, and when a tension body layer is formed on the surface layer, the thickness of the tension body layer can be reduced. The height difference at the joint becomes lower, improving drive performance. It is also advantageous for seamless processing. Furthermore, it becomes possible to provide functional layers such as a dielectric layer and a photoreceptor layer directly on the back layer without particularly providing a tension layer.

In the invention of claim (2), since some of the short fibers are exposed from the roller contact surface of the back layer, they come into contact between the belt and the roller or through the short fibers, and close contact is avoided, thereby reducing friction. The coefficient is reduced and temperature and humidity dependence are reduced, improving the sliding characteristics of the roller contact surface of the flat belt, and reducing the thrust force when the flat belt shifts to one side, making it easier to correct the meandering of the flat belt. becomes.

In the invention of claim (3), the short fibers have a length of 0.5 to 10
Since it is set to o+m, the rigidity and flexibility in the circumferential direction of the belt can be appropriately adjusted.

In the invention of claim (4), the short fibers have a length of 0. 5-10
Since it is made of aramid fibers with a thickness of 1.5 mm, the aramid resin's high elastic modulus, good sliding properties, and stability against temperature changes ensure smooth running of the flat belt, as well as the high heat resistance of the aramid resin. Due to its nature, the short fibers do not break even when subjected to grinding to expose a portion of the short fibers, making production easier.

In the invention of claim (5), since the thickness of the back layer is set to 100 μm or more depending on the size of the foreign object, the elasticity of the elastic material, etc., effects such as prevention of belt damage can be obtained. .

In the invention of claim (6), the flat belt according to each of the above inventions is wound around a plurality of roller members and driven, thereby achieving characteristics such as excellent sliding characteristics and low thrust force when the flat belt shifts to one side. The invention will be put to good use and the effectiveness of each invention will be obtained.

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

FIG. 2 shows the entire flat belt drive device housed in the electrophotographic apparatus according to the present invention, which is a three-axis photoreceptor belt drive device. In FIG. 2, 1 is a 10th roller member that functions as a driving roller rotationally driven by a motor 5, 2 is a 20th roller member that functions as a driven roller, and 3
is a 30th roller member which functions as a tension roller, and each roller member 1.2.3 has a photoreceptor layer laminated on the surface of a base material, which is a flat belt in the present invention. The belt 4 is provided with a hook so that it can run, and this photoreceptor belt 4 functions as a photoreceptor of an electrophotographic apparatus.

Further, each of the roller members 1, 2.3 is fitted into a stepped roll-shaped metal shaft member 1a, 2a, 3a, and a portion of the shaft member 1a, 2a, 3a excluding both ends of the large diameter portion. The outer diameter of each cylindrical member 1b, 2b, and 3b is set to be equal.

The cylindrical member 1b forming the belt contact surface of the 10th roller member 1, which is the driving roller, is made of EPDM crosslinked rubber, and the cylindrical member 1b, which is the non-driving roller, forms the belt contact surface of the 10th roller member 1. The cylindrical members 2b and 3b of the 30th-ra members 2 and 3 are made of hard plastic.

Furthermore, flanges IC1IC-3c, 3c are provided at both ends of the belt contact surfaces of each of the roller members 1-3 as belt guide members for regulating the lateral movement of the photoreceptor belt 4. 10- To explain the mounting structure using one end of the flange member 1 as an example, as shown in FIG. 3, the flange I
C is attached to the 10th-R member 1 by fitting a flat ring made of metal or sliding plastic such as fluororesin to the shaft member 1a so as to abut the end of the cylindrical member 1b. installed. The other end of the 10th-ra member 1 and the 2nd. A similar mounting structure is also provided at both ends of the 30th ring member 2°3.

On the other hand, as shown in FIG. 1, the photoreceptor belt 4 includes a tension layer 4a made of a tension material such as polyester,
A back layer 4b made of an elastic body made of M-based crosslinked rubber mixed with a large number of short organic fibers F, F, etc., and a surface layer made of a photoreceptor formed on the upper side of the tension body layer 4a. It has three layers with 4c.

However, in the structure of the photoreceptor belt 4, it is not necessarily necessary to separately provide the tension layer 4c made of a dielectric or a photoreceptor on the tension layer 4a as in the above embodiment, and the dielectric material is directly used as the back layer 4b. It is also possible to simplify the structure by providing it above.

As shown in FIG. 3, the photoreceptor belt 4 is
At both ends, the back layer 4b is a tension body layer 4a and a tension body layer 4a.
It is formed so as to protrude further in the belt width direction.

Further, the short fibers F in the back layer 4b of the photoreceptor belt 4,
F, . . . are in the belt circumferential direction of the photoreceptor belt 4,
Further, it is oriented so as to be slightly inclined toward the belt thickness direction from a direction parallel to the belt surface, and a portion thereof is formed to be exposed from the roller contact surface of the back layer 4b.

Note that the short fibers F, F, . . . may be oriented in a direction parallel to the belt surface.

Materials for the short fibers F include organic fibers such as PET, nylon, aramid, cotton, and cellulose, as well as inorganic fibers such as carbon fibers, inorganic fibrous fillers such as silicon carbide, iron oxide, and titanic acid, and liquid polyester fibers. , ultra-high molecular weight polyethylene fibers, etc. can be used.

Furthermore, the elastic material that is the matrix of the back layer 4b is not limited to general rubber materials, and for example, urethane, thermoplastic elastomer, etc. can be used.

The photoreceptor belt 4 is formed into an endless belt that is continuous in the circumferential direction, ie, has no seams.

Short fibers F of the back layer 4b of the photoreceptor belt 4.

F, . . . are generally kneaded into an elastic body such as rubber, and are sometimes subjected to adhesive treatment.

Furthermore, in order to expose the short fibers F, F, .

Therefore, in this embodiment, by providing the back layer 4b made of an elastic material under the tension body layer 4a of the photoreceptor belt 4, the mounting tension necessary for driving the belt is reduced, and as a result, the back layer 4b Coupled with the softness of the photoreceptor belt 4, damage to the photoreceptor belt 4 is minimized even when foreign matter such as toner or paper powder gets caught. Furthermore, since the belt rigidity hardly changes even if the thickness of such an elastic body is increased, the belt thickness can be increased without impairing the flexibility necessary to keep the belt running smoothly. and,
Since the thickness of the photoreceptor belt 4 can be increased, wrinkles can be prevented from occurring while the photoreceptor belt 4 is running.

Then, the short fibers F, F, .

Since F, . . . are oriented in the circumferential direction of the belt, the rigidity and flexibility in the circumferential direction of the belt can be appropriately adjusted.

In particular, the orientation of the short fibers F, F, . . .
Since the tension in the circumferential direction of the belt is shared, the thickness of the tension body layer 4a can be reduced, the level difference at the joint portion is lowered, and the driving performance is improved.

Moreover, seamlessness becomes easy. Furthermore, the back layer 4
Due to the improved rigidity of b, it is not necessary to provide the tension layer 4a, and it becomes possible to directly provide a functional layer such as a dielectric layer or a photoreceptor layer on the back layer 4b.

In particular, the short fibers F, F, .
If it is exposed from the roller contact surface in b, the stiffness improvement effect is inferior to when it is oriented parallel to the belt surface, but
Short fiber F between belt and roller.

Contact is made through F,..., and close contact between the two is avoided,
Since the gripping force of the short fibers F, F, ... will govern the sliding properties between them, the friction coefficient will be reduced, and the dependence of the friction coefficient on temperature and humidity will be almost eliminated, and the sliding properties will be improved. At the same time, the thrust force when the photoreceptor belt 4 is shifted to one side is reduced, making it easier to restrict the lateral movement of the photoreceptor belt 4.

The material of the short fibers F, F, ... is not limited to the above examples, but since they are required to have a certain degree of rigidity and a small coefficient of friction, organic fibers or carbon fibers may be used. One or more types of fibers selected from either one or both of them can be used.

Here, the length of the short fibers F, F, ... is 0.5 to 10 mm in order to have appropriate rigidity in the direction in which the flat belt or short fibers are oriented, and to facilitate manufacturing. Preferably within the range.

In particular, short fibers F, F,... or length 0.5 to 10 m
In the case of II aramid fibers, aramid resins have high rigidity, good sliding properties at high PV values, and a wide stability range against temperature changes, so they are used under conditions where concentrated loads are applied. Even at times, the sliding properties are maintained well under a wide range of environmental conditions.

The thickness of the back layer 4b of the photoreceptor belt 4 depends on the size of the foreign object,
The thickness is preferably 100 μm or more in view of the elasticity of the elastic material, and in this case, the above-mentioned effects such as preventing belt damage and wrinkles and improving rigidity become particularly noticeable.

By using the photoreceptor belt 4 having such a configuration in a belt drive device that drives the belt by winding it around a plurality of roller members 1 to 3, the various characteristics described above can be exhibited. This makes it possible to provide a flat belt drive device with good drive accuracy and less meandering, which is required in electrophotographic processes and the like.

In addition, in the above embodiment, flanges lc, lc-3c, 3c (belt guide members) were provided at both ends of each roller member 1 to 3, but it is not necessary to provide belt guide members to all roller members 1 to 3. . Further, it is not necessary to provide the belt guide member on each of the roller members 1 to 3, and it is sufficient to provide the belt guide member on any part of the area where the belt runs.

Further, as in the above embodiment, by forming the back layer 4b at the end of the photoreceptor belt 4 so as to protrude outward from the tension body layer 4a, the elastic body comes into contact with the belt guide member. The lateral movement of the photoreceptor belt 4 is restricted, and even if the end surfaces of the belt constantly come into contact with each other while the photoreceptor belt 4 is running, damage such as abrasion of the belt guide member can be effectively prevented.

The present invention is not limited to the photoreceptor belt 4 used as a photoreceptor belt as in the above embodiment, but can also be applied to flat belts for general mechanical devices, but is particularly applicable to transfer belts for electrophotographic devices. When used as a conveyor belt, the electrophotographic process requires precise driving of the photoreceptor belt 4 in order to maintain good image forming characteristics.
Since changes in environmental conditions such as humidity are large, effective use of the functions of the flat belt of the present invention can be highly effective.

Further, the flat belt drive device is not limited to the three-axis system as in the above embodiment, and is not limited to the one provided with a belt guide member. Needless to say, the present invention can also be applied to a device equipped with a meandering correction mechanism for displacing the axis of the roller in a direction that eliminates meandering.

(Effects of the Invention) As explained above, according to the invention of claim (1), at least two layers are laminated on the flat belt, and the back layer of the two layers is short a! Since it is made of an elastic material containing fibers and the short fibers are oriented in the circumferential direction of the belt, the thickness of the tension layer can be reduced while maintaining appropriate belt rigidity.

According to the invention of claim (2), in the invention of claim (1), a part of the short fibers is exposed from the roller contact surface of the back layer, so that the friction coefficient can be reduced and the temperature and humidity of the friction coefficient can be reduced. It is possible to improve the sliding characteristics by stabilizing the flat belt, and to improve the belt lateral movement regulating function by reducing the thrust force when the flat belt shifts to one side.

According to the invention of claim (3), the above claim (1) or (
In the invention of 2, the length of the short fibers is 0.5 to 10 ma+
Since the belt is closed, the rigidity and flexibility of the belt can be adjusted appropriately.

According to the invention of claim (4), in the invention of claim (3), the short fibers are aramid fibers having a length of 0.5 to 10 mm, so that the aramid resin has high rigidity, good sliding properties, By utilizing characteristics such as stability against temperature changes, the effects of each of the above inventions can be more significantly obtained, and
Due to its high heat resistance, short fibers can be easily exposed through grinding.

According to the invention of claim (5), the above claims +1), +
In the invention of 21°(3) or (4), since the thickness of the back layer is 100 μm or more, it is possible to effectively prevent damage caused by biting of foreign objects and improve rigidity.

According to the invention of claim (6), a plurality of rollers are arranged, and the flat belt according to the invention of claim [1], (2+, [3+, (4) or (5)) is arranged on the plurality of rollers. Since the flat belt driving device is configured to be wound and driven, by exhibiting the functions of the flat belt of each of the above inventions, it is possible to provide a flat belt driving device with good driving accuracy that can be applied to electrophotographic processes, etc. can.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is similar to I-1 in FIG.
2 is a perspective view schematically showing a three-axis flat belt drive device, and FIG. 3 is a longitudinal sectional front view of the vicinity of the belt guide member. 1 10th La member 2 20th La member 3 30th La member 4 Photoreceptor belt (flat belt) 4a Tension body layer 4b Back layer F Short fiber 〆-

Claims (1)

[Claims] (1) A flat belt formed by laminating at least two layers, wherein the back layer of the two layers is made of an elastic material mixed with short fibers, and the short fibers extend in the belt circumferential direction. A flat belt characterized by being oriented. (2) A claim characterized in that the short fibers are oriented so as to be slightly inclined from a direction parallel to the belt surface toward the belt thickness direction, and a portion of the short fibers are exposed from the roller contact surface of the back layer. The flat belt described in item (1). (3) The length of the short fibers is 0.5 to 10 mm (
The flat belt described in 1) or (2). (4) Claim (3) wherein the short fibers are aramid fibers having a length of 0.5 to 10 mm.
Flat belt as described. (5) The flat belt according to claim (1), (2), (3) or (4), wherein the thickness of the back layer is 100 μm or more. (6) comprising a plurality of roller members;
A flat belt driving device characterized in that the flat belt according to (2), (3), (4) or (5) is wound around the plurality of roller members and driven.