JP3837246B2 - Endless belt, belt driving device, and image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an endless belt used in a belt driving device that is stretched by a plurality of rollers and driven so that the surface moves along a predetermined path, and a belt driving device, a copying machine, a facsimile machine, a printer, etc. The present invention relates to an image forming apparatus using the belt driving device as a carrying and conveying device such as a photosensitive belt and an intermediate transfer belt of the image forming device.
[0002]
[Prior art]
Conventionally, as a belt driving device that stretches an endless belt on a plurality of rollers and drives the endless belt to move along a predetermined path, one of the rollers rotates as a driving source, and the rotation of the roller Some drive the endless belt by force. In this case, if there is a mechanical error in the roundness or straightness of each roller, the parallelism between the rollers, or the belt circumference at each point in the width direction of the endless belt, the belt is driven. The belt does not drive well, meanders, or approaches one side in the belt width direction.
[0003]
In addition, in a carrier such as a photosensitive belt or an intermediate transfer belt in an image forming apparatus such as a copying machine, a facsimile, or a printer, if the meandering or deviation occurs as described above, the image carried on the belt surface is affected. However, for example, problems such as image shift and unevenness occur.
[0004]
As a measure to solve the above-mentioned problems of the image forming apparatus, a guide that hits the edge of the roller over which the belt is stretched or the flange at the end of the roller is provided on the endless belt so that the surface movement direction of the endless belt What regulates an unexpected shift in an orthogonal direction is known.
[0005]
For example, in Japanese Patent Application Laid-Open No. 10-063140, in the belt-like photoconductor provided with the meandering-preventing beat on the inner peripheral surface on both side edges, the end face of each beat on the side in contact with the corner of the roll, Formed on inclined surfaces that are spaced apart from each other toward the inner periphery of the beat, so that the beat does not run on the roll, the side edge of the belt-like photoreceptor is temporarily bent, or cracks (cracks in the photosensitive layer on the surface) ) Has been proposed.
[0006]
[Problems to be solved by the invention]
However, in the belt driving device using the endless belt provided with the guide, it is possible to drive without causing meandering or shifting, but it has been found that the endless belt is cracked.
The following may be considered as the cause of the occurrence of cracks. The material of an endless belt used for an intermediate transfer belt of an image forming apparatus is generally a hard belt formed by dispersing carbon black in polyimide, polyarylate, fluorine resin, etc. and forming a desired resistance value. The guide for preventing meandering is provided over the entire circumference of the belt, but there is a guide seam at one place on the circumference of the belt.
In the case where the guide is provided on the hard endless belt as described above, the tension is stretched between the rollers while being driven to move along a predetermined path by being stretched by a plurality of rollers. The bending and extension are repeated between the flat surface portion and the curved surface portion wound around the roller. For this reason, stress is applied to the belt portion in the vicinity of the joint of the guide and cracks are generated. Furthermore, there is a risk that the belt may be torn from the cracked portion.
[0007]
The present invention has been made in view of the above problems, and an object of the present invention is to provide an endless belt capable of preventing the occurrence of cracks due to belt driving of an endless belt provided with a guide for preventing the occurrence of meandering and shifting. An endless belt driving device and an image forming apparatus using the belt driving device are provided.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the endless belt according to claim 1 is an endless belt used in a belt driving device that is stretched around a plurality of rollers and is driven so that the surface moves along a predetermined path. In order to prevent meandering of the endless belt when driven by a device, it has a meandering prevention guide at the belt end in a direction orthogonal to the belt surface movement direction, and the meandering on the inner peripheral surface of the endless belt A reinforcing member that reinforces the joint portion is provided between the endless belt and the meandering prevention guide at the joint portion in the belt surface movement direction of the prevention guide. .
In the endless belt according to claim 1, a joint portion in the belt surface moving direction of the meandering prevention guide provided on the endless belt is reinforced by a reinforcing member, and the endless belt is stretched between the rollers, Even if bending and stretching are repeated between the curved part wound around the roller, the bending and stretching of the seam part does not become larger than other parts, and stress is not concentrated on the belt part corresponding to the seam part. To do. Moreover, in the endless belt according to claim 1, a reinforcing member that reinforces the joint portion of the guide is provided on the inner peripheral surface of the belt, and a meander-preventing guide is provided on the inner peripheral surface, whereby the reinforcing member and the endless belt are provided. The foreign material is less likely to enter between and the reinforcing member is difficult to peel off.
The belt drive device according to claim 2 is a belt drive device that drives an endless belt so as to be stretched by a plurality of rollers so that the surface moves along a predetermined path. It is characterized by driving.
In the belt driving device according to claim 2, by performing belt driving, the endless belt repeatedly bends and stretches between a flat surface portion stretched between the rollers and a curved surface portion wound around the rollers. However, stress does not concentrate on the belt portion corresponding to the seam portion. In addition, a reinforcing member that reinforces the joint portion of the guide is provided on the inner peripheral surface of the belt, and further, a meandering prevention guide is provided on the inner peripheral surface thereof, so that foreign matter does not easily enter between the reinforcing member and the endless belt. The reinforcing member is difficult to peel off.
According to a third aspect of the present invention, there is provided the belt driving device according to the second aspect, further comprising position detecting means for detecting a position of the reinforcing member provided in the endless belt in the belt surface movement direction. .
In the belt driving device according to the third aspect, the position detecting means detects the position of the endless belt of the reinforcing member in the belt surface moving direction.
The belt drive device according to claim 4 is the belt drive device according to claim 3, wherein a protrusion protruding from a belt end in a direction orthogonal to the belt surface movement direction is formed on the reinforcing member provided on the endless belt, The protrusion is detected by a position detection means.
Here, as the position detection means, for example, there is a method of detecting a protrusion using a photo interrupter.
In particular, in the belt driving device according to the fourth aspect, the position in the belt surface moving direction is detected by detecting the protruding portion protruding from the belt end in the direction orthogonal to the belt surface moving direction by the position detecting means.
The image forming apparatus according to claim 5 is formed by a latent image forming unit that forms a latent image on the surface of the image carrier, a developing unit that visualizes the latent image on the surface of the image carrier, and the developing unit. A transfer means for transferring the visible image to the recording medium, and driving the endless belt carrying the latent image or the predetermined substance on the surface so as to move along the predetermined path by the belt driving device. 5. An image forming apparatus having at least one belt conveying means for conveying an image or a predetermined substance, wherein the belt driving apparatus according to claim 2, 3 or 4 is used as a belt driving apparatus used for the belt conveying means. It is what.
Here, examples of the predetermined substance include a visible image formed by the developing unit and a transfer material onto which the visible image is transferred.
According to a fifth aspect of the present invention, the latent image or the latent image is formed on the endless belt without cracks by using the belt driving device according to the second, third or fourth aspect of the present invention for the belt conveying means for conveying the latent image or the predetermined substance. Alternatively, a predetermined substance is supported and transported.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment in which the present invention is applied to an electrophotographic copying machine as an image forming apparatus will be described.
Hereinafter, an embodiment in which the present invention is applied to a wet electrophotographic copying machine (hereinafter simply referred to as “copying machine”) which is a wet image forming apparatus will be described.
First, an outline of the copying machine according to the present embodiment will be described. FIG. 1 is a schematic configuration diagram of a main part of a copying machine according to the present embodiment. Around the photosensitive drum 10 as a latent image carrier, a charging roller 20, an optical writing unit 30, a developing unit 40, an intermediate transfer belt 50, a photosensitive drum cleaning unit 60, and the like are disposed. A secondary transfer roller 70 and an intermediate transfer belt cleaning unit 51 are also provided as a transfer means for transferring the developed image onto a transfer sheet (not shown) as a final transfer material, facing the intermediate transfer belt 50. Yes. Further, the developing unit 40 is provided with a yellow developing unit 40Y, a black developing unit 40B, a magenta developing unit 40M, and a cyan developing unit 40C around the photosensitive drum 10, and the developing unit 40 is a driving means such as a solenoid (not shown). Thus, it is configured to be able to contact and separate from the photosensitive drum 10.
[0021]
The photosensitive drum 10 as a latent image carrier is rotationally driven in the direction of the arrow at a constant speed during copying by driving means such as a motor (not shown). After the charging roller 20 is uniformly charged in the dark, the optical writing unit 30 forms an electrostatic latent image on the photosensitive drum 10 by irradiating and forming writing light based on the image information. The This image information is monochromatic image information obtained by separating a desired full-color image into color information of yellow, magenta, cyan, and black. Then, the development units 40Y, 40B, 40M, and 40C of predetermined colors are controlled so as to contact the photosensitive drum 10 according to the electrostatic latent image formed on the photosensitive drum 10, and predetermined yellow and magenta, respectively. , Cyan and black toners are used to form each color image on the photosensitive drum 10. The respective color images formed on the photosensitive drum 10 are sequentially superimposed on yellow, magenta, cyan, and black single colors on an intermediate transfer belt 50 as an intermediate transfer member that is driven at the same speed as the photosensitive drum 10. The primary transfer. The yellow, magenta, cyan, and black images superimposed on the intermediate transfer belt 50 are collectively transferred by the secondary transfer roller 70 onto transfer paper (not shown) conveyed from the paper feed cassette 80 to the transfer unit. Then, after the transfer is completed, the transfer sheet (not shown) is fixed by the fixing unit 90 and discharged onto the discharge tray 91.
[0022]
The developer on the photosensitive drum 10 that has not been transferred onto the intermediate transfer belt 50 is removed from the photosensitive drum 10 by the photosensitive drum cleaning unit 60. Further, the residual developer on the intermediate transfer belt 50 is removed by the blade 52 of the intermediate transfer belt cleaning unit 51. Thereafter, the residual potential is removed from the surface of the photosensitive drum 10 by a neutralizing lamp (not shown) to prepare for the next copy.
[0023]
FIG. 2 is a perspective view of the intermediate transfer belt 50. The intermediate transfer belt 50 of the present embodiment is an endless belt, and the material thereof has been adjusted to a predetermined resistance value by dispersing carbon black in a resin such as polyimide, polyarylate, or fluorine. Moreover, the thin thing about 0.05-0.15 mm in thickness is used.
In the intermediate transfer belt 50, meandering prevention guides 54 are bonded to the inner peripheral surfaces at both ends in the belt width direction. The guide 54 is made of a rubber material such as urethane, has a thickness of about 0.5 to 1.0 mm, and is not endless but is bonded to a single elongated belt along the inner peripheral surface of the intermediate transfer belt 50. The end portions face each other to form a seam 54a.
The intermediate transfer belt 50 is stretched around a roller of a belt driving device 45 having a plurality of rollers 53a, b, c, and d as shown in FIG. 1, and is driven in the direction of arrow A by driving of the driving roller. The The guide 54 abuts against the edges of the rollers 53 a, b, c, and d that stretch the intermediate transfer belt 50 and the flange at the end of the roller, thereby causing the guide 54 in a direction orthogonal to the surface movement direction of the intermediate transfer belt 50. Unexpected deviation is regulated to prevent the intermediate transfer belt 50 from meandering and shifting.
However, the intermediate transfer belt 50 repeatedly bends and extends between a flat portion stretched between the rollers and a curved portion wound around the rollers. At this time, the belt portion in the vicinity of the joint where the guide 54 is interrupted is repeatedly bent and stretched intensively, so that cracks are gradually broken in this portion. The copying machine of this embodiment has a configuration for preventing the intermediate transfer belt 50 from cracking. Next, the characteristic part of this embodiment is demonstrated.
[0024]
FIG. 3 is a partially enlarged view of the vicinity of the joint portion of the guide 54. In this figure, a reinforcing member 55 that reinforces the seam is made of a resin that extends a predetermined length from the seam to both sides in the belt longitudinal direction at a position facing the seam on the outer peripheral surface side of the intermediate transfer belt 50. A reinforcing member 55 a made of the above film is affixed to the intermediate transfer belt 50. The reinforcing member 55a has a thickness of about 0.05 to 0.2 mm and can be made of, for example, PET, Teflon, polyimide, or the like.
[0025]
As described above, if the reinforcing member 55a is attached to the intermediate transfer belt 50 in the vicinity of the joint portion of the guide 54, even if the intermediate transfer belt 50 is repeatedly bent and stretched by driving, stress is applied to the intermediate transfer belt 50 portion corresponding to the joint portion. It is possible to prevent the occurrence of cracks in the intermediate transfer belt 50 without being concentrated. Thereby, the life of the intermediate transfer belt 50 can be extended.
[0026]
FIG. 4 is a plan view according to a first modification of the reinforcing member 55. In this example, the reinforcing member 55a is attached to the inner peripheral surface side of the intermediate transfer belt 50, and the end portion of the guide 54 runs on the inner peripheral side.
When the reinforcing member 55b is provided on the inner peripheral surface of the intermediate transfer belt 50 as described above, the reinforcing member 55b is attached to the side of the intermediate transfer belt 50 that does not carry an image. Since it is difficult for foreign matters such as toner to enter between them, the reinforcing member 55b is difficult to peel off. Thereby, the durability of the reinforcing member 55b can be improved.
[0027]
Further, the surface of the reinforcing member 55b has a reflectance satisfying the specification of the reflection type photo interrupter 56 as a position detecting means, and a position detecting marker in the belt surface moving direction when the intermediate transfer belt 50 is driven. It also has the role of. As a method for enabling the reinforcing member 55b to be detected by the reflective photointerrupter 56, for example, a white resin film is used as the material of the reinforcing member 55b, a paint having a high reflectance is applied to the surface of the reinforcing member 55b, or Ink with high reflectivity may be printed. The belt driving device 45 for the intermediate transfer belt is provided with a reflective photo interrupter 56 at a predetermined position facing the inner peripheral surface of the intermediate transfer belt 50.
When the intermediate transfer belt 50 is driven and reaches the reinforcing member 55 b at a position facing the reflective photo interrupter 56, the reflection of the reinforcing member 55 b is reflected by the intermediate transfer belt 50 and the guide 54 having a low reflectance in which carbon black is dispersed. Since the rate is high, the light of the reflective photointerrupter 56 is reflected and the position is detected. Thus, by increasing the reflectance of the reinforcing member 55b as compared with the guide 54 and the intermediate transfer belt 50, the reinforcing member 55b can function as a position detection marker.
[0028]
FIG. 5 is a plan view according to a second modification of the reinforcing member 55. This is because the reinforcing member 55 is not attached to the inner peripheral surface of the intermediate transfer belt 50 as shown in FIG. 4, but is also attached to the outer peripheral surface of the intermediate transfer belt 50 as shown in FIG. It is. Also in this example, the reflectance of the reinforcing member 55 c is set higher than that of the intermediate transfer belt 50. The belt driving device 45 of the intermediate transfer belt 50 is provided with a reflection type photo interrupter 56 (see FIG. 1) so as to face the position where the reinforcing member 55c in the width direction of the intermediate transfer belt 50 is provided.
As described above, when the reinforcing member 55 c is attached to the outer peripheral surface of the intermediate transfer belt 50, the position of the intermediate transfer belt 50 can be easily detected by providing the reflection type photo interrupter 56 outside the intermediate transfer belt 50. Can be done.
[0029]
Here, when the intermediate transfer belt 50 stretched around a plurality of rollers is driven, the intermediate transfer belt 50 may fluctuate in the vertical direction at a portion between the rollers. The fluttering of the intermediate transfer belt causes an unexpected change in the distance between the reinforcing member 55 provided on the intermediate transfer belt 50 and the reflection type photo interrupter 56, and decreases the accuracy of position detection of the intermediate transfer belt 50. There is a risk. Next, a configuration capable of preventing such a decrease in the accuracy in detecting the position of the intermediate transfer belt 50 will be described.
[0030]
6 is a partially enlarged view of the vicinity of the joint portion of the guide 54 according to the third modified example of the reinforcing member 55, and FIG. 7 is a plan view according to the third modified example. In FIG. 6, the reinforcing member 55d is affixed on the outer peripheral surface side of the intermediate transfer belt 50 at a position facing the seam portion as in FIG. In the third modification, the reinforcing member 55d is provided with a protrusion t protruding from the end of the intermediate transfer belt 50 in the direction orthogonal to the surface movement direction of the intermediate transfer belt 50. Further, in this example, instead of providing the belt drive device 45 with the reflection type photo interrupter 56, the protrusion t that moves as the intermediate transfer belt 50 is driven has a predetermined distance from both the upper and lower directions at a certain position. A transmissive photo interrupter 57 is provided so as to be sandwiched between the two. The reinforcing member 55d has a transmittance that is low enough to satisfy the specifications of the transmissive photointerrupter 57. For example, a black resin film may be used.
In the above configuration, when the intermediate transfer belt 50 is driven and the protrusion t of the reinforcing member 55d reaches the position where the transmission photo interrupter 57 is located, the transmission photo interrupter 57 detects the protrusion t. As a result, the position of the intermediate transfer belt 50 in the surface movement direction can be detected.
[0031]
According to the third modified example, since the projection t is detected using the transmissive photo interrupter 57, even when the belt surface vibrates up and down when the intermediate transfer belt 50 is driven, the vertical displacement is slightly increased. The position of the intermediate transfer belt 50 in the surface movement direction can be detected accurately without being affected.
[0032]
FIG. 8 is a plan view according to a fourth modification. The reinforcing member 55d has a projection t as in FIG. 7, and is provided so that the transmissive photointerrupter 57 can detect the projection t. In FIG. 8, the reinforcing member 55e is attached to the inner peripheral surface side of the intermediate transfer belt 50, and the end portion of the guide 54 runs on the inner peripheral side.
With the above configuration, the position can be detected with high accuracy without being affected by the vertical displacement of the intermediate transfer belt 50, and the durability of the reinforcing member 55e can be improved by making the reinforcing member 55e difficult to peel off.
[0033]
As described above, when the present invention is applied to the intermediate transfer belt 50 of a copying machine, it is possible to prevent meandering and shifting of the intermediate transfer belt 50 and to prevent the occurrence of cracks. The primary transfer onto the intermediate transfer belt and the secondary transfer onto the transfer sheet of the superimposed image formed on the intermediate transfer belt 50 can be performed satisfactorily, and a good image free from deviations and unevenness can be formed. Further, since the crack of the intermediate transfer belt 50 can be prevented, the life of the intermediate transfer belt 50 can be extended.
[0034]
In the present embodiment, the present invention is applied to the intermediate transfer belt 50 of the copying machine, but in addition, a carrier that carries a predetermined substance on the surface thereof, such as a photosensitive belt in which the photosensitive drum 10 is belt-shaped. The present invention can be widely applied to a belt that uses an endless belt and conveys the endless belt along a predetermined path.
[0035]
【The invention's effect】
According to the endless belt of claim 1, since the stress due to the bending and stretching of the belt can be prevented from concentrating on the belt portion corresponding to the joint portion of the guide, the belt driving device provided with the guide for preventing the occurrence of meandering and deviation The endless belt used in the present invention has an excellent effect of preventing the occurrence of cracks due to belt driving.
This also has an excellent effect of extending the life of the endless belt.
Furthermore, since the intrusion of foreign matter between the reinforcing member and the endless belt can be prevented, the reinforcing member is hardly peeled off, and there is an excellent effect that the durability of the reinforcing member can be improved.
According to the belt driving device of the second aspect, there is an excellent effect that it is possible to prevent the occurrence of cracks due to the driving of the endless belt.
Further, since the life of the endless belt is extended, there is an excellent effect that the repair or replacement cycle of the belt is extended and the maintenance cost can be reduced.
According to the belt driving device of the third and fourth aspects, the position of the endless belt in the belt surface movement direction can be detected by detecting the position of the reinforcing member of the endless belt. As compared with the above, there is an excellent effect that the cost can be reduced.
According to the belt driving device of the fourth aspect, there is an excellent effect that the position in the belt surface moving direction can be easily detected by detecting the protruding portion protruding from the belt end.
In addition, if the projection is detected using a transmissive photo interrupter as the position detection means, even if the belt surface undulates or fluctuates when driving the endless belt, it is affected by some vertical displacement. There is an excellent effect that the position can be detected with high accuracy.
According to the image forming apparatus of the fifth aspect, since it is possible to prevent the occurrence of cracks while preventing meandering and shifting of the carrier, it is possible to reliably transport a latent image or a predetermined substance carried on the surface of the carrier. There is an effect.
In addition, since the latent image, the visible image as the predetermined substance, and the transfer material can be transported to the next process area, there is an excellent effect that a good image without deviation or unevenness can be formed.
[0041]
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a main part of a wet image forming apparatus according to an embodiment.
FIG. 2 is a perspective view of an intermediate transfer belt.
FIG. 3 is a partially enlarged view near the joint portion of the guide.
FIG. 4 is a plan view according to a first modification of the reinforcing member.
FIG. 5 is a plan view according to a second modification of the reinforcing member.
FIG. 6 is a partially enlarged view of the vicinity of a guide joint portion according to a third modification of the reinforcing member.
FIG. 7 is a plan view according to a third modification of the reinforcing member.
FIG. 8 is a plan view according to a fourth modification of the reinforcing member.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Photosensitive drum 20 Charging roller 30 Optical writing unit 40 Developing unit 40B Black developing unit 40C Cyan developing unit 40M Magenta developing unit 40Y Yellow developing unit 45 Belt driving device 50 Intermediate transfer belt 51 Intermediate transfer belt cleaning unit 54 Guides 55a, b , C, d, e Reinforcing member 56 Reflection type photo interrupter 57 Transmission type photo interrupter 60 Photosensitive drum cleaning unit 70 Secondary transfer roller 80 Paper feed cassette 90 Fixing unit 91 Paper discharge tray t Projection

Claims (5)

In an endless belt used in a belt driving device that is stretched by a plurality of rollers and driven so that the surface moves along a predetermined path,
In order to prevent meandering of the endless belt when driven by the belt driving device, it has a meandering prevention guide at a belt end in a direction perpendicular to the belt surface moving direction,
A reinforcing member that reinforces the joint portion is located between the endless belt and the meander prevention guide at the joint portion in the belt surface moving direction of the meander prevention guide on the inner peripheral surface of the endless belt. An endless belt characterized by the provision . The belt drive device surface is stretched in a roller made of multiple drives an endless belt to move along a predetermined path,
A belt driving device for driving the endless belt according to claim 1 by the belt driving device. In the belt drive device of Claim 2 ,
A belt driving device comprising position detecting means for detecting the position of the reinforcing member provided on the endless belt in the belt surface movement direction. In the belt drive device of Claim 3 ,
The reinforcing member provided on the endless belt is formed with a protruding portion protruding from a belt end in a direction orthogonal to the belt surface moving direction, and the protruding portion is detected by the position detecting means. Belt drive device. A latent image forming unit that forms a latent image on the surface of the image carrier, a developing unit that visualizes the latent image on the surface of the image carrier, and a visible image formed by the developing unit is transferred to a recording medium. A belt for transferring the latent image or the predetermined substance by driving an endless belt carrying the latent image or the predetermined substance on the surface so as to move along a predetermined path by a belt driving device. In an image forming apparatus having at least one conveying unit,
As a belt driving apparatus used in the belt conveying unit, according to claim 2, 3 or the image forming apparatus characterized by using four of the belt drive.

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