JP2000185838A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To mount an endless-shaped belt to an adequate position of a plurality of rolls including a driving roll, by evacuating a positioning member to a position in non-contact with the endless-shaped belt during image forming. SOLUTION: A rear side frame 32 and a front side frame that support a roll linked with an intermediate transfer body belt are pressed down to a prescribed position around a fulcrum. Thus, a first link 51 mounted to the rear side frame 32 is returned to the front side, and a second link 53 rotatably connected with the other portion of the first link 51 oscillated around a fulcrum 52. As a result, a positioning plate 57 integrally mounted to the other portion of the second link 53 via a support member 56 evacuates to a position that does not disturbs an image forming operation. In this structure, an endless- shaped belt can be mounted to an adequate position, and failure or damage can be prevented from occurring on the endless-shaped belt.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electrophotographic copying machine or a printer, and more particularly to a photosensitive member or an intermediate transfer member for carrying a visualized image and an endless transfer member for transferring a transfer material. The present invention relates to an image forming apparatus using a belt.

[0002]

2. Description of the Related Art Conventionally, an image forming apparatus such as an electrophotographic copying machine or a printer uses a photosensitive member or an intermediate transfer member for carrying a visualized image and an endless belt as a transfer material conveying member. There is something. In this type of image forming apparatus, as a photosensitive member that carries a visualized image,
An endless photoreceptor belt, an intermediate transfer belt for temporarily transferring toner images of different colors sequentially formed on a photoreceptor drum, a plurality of photoreceptors for forming toner images of different colors Drums are arranged in parallel with each other, and a transfer material transport belt is used as a member for transporting a transfer material for sequentially transferring toner images of different colors formed on the plurality of photosensitive drums, respectively. . In these image forming apparatuses, an endless belt such as a photoreceptor belt, an intermediate transfer belt, or a transfer material conveying belt is stretched by a plurality of rolls including a drive roll, and the drive roll is driven to rotate. In this way, the degree of freedom in setting the image writing position, the developing position, and the primary and secondary transfer positions of the toner image is increased, and the color image forming apparatus is particularly compact. It has a great feature that enables

On the other hand, in the case of an image forming apparatus using an endless belt such as the photoreceptor belt, the intermediate transfer member belt, or a transfer material conveying belt, the driving is performed when the endless belt is driven. Angular velocity fluctuations due to errors in accuracy when manufacturing rolls that support belts such as rolls, and velocity fluctuations due to geometrical eccentricity of drive rolls appear on the belt, and transport between the drive rolls and the belt An error may occur in the amount, or deviation or meandering may occur in an axial direction orthogonal to the process direction. As described above, when the endless belt such as the photoreceptor belt, the intermediate transfer belt, or the transfer material conveying belt is shifted or meandered in the axial direction, the endless belt such as the photoreceptor belt or the intermediate transfer belt is generated. The gradation, graininess, and color of the toner image exposed, developed, and transferred onto the belt are reduced, and the image quality is reduced.

[0004] Therefore, in order to improve the gradation, graininess and hue in the halftone image quality required for an office or the like, an endless belt such as a photoreceptor belt or an intermediate transfer belt is usually used. Is required to be driven with high precision.

As a technique for preventing the endless belt from shifting or meandering in the axial direction, a technique for preventing the endless belt from shifting toward the axial end of a roll supporting an endless belt such as a driving roll. It has already been proposed to provide an abutting member for preventing the meandering and meandering.

However, in the case of this technique, when the endless belt frequently comes into contact with an abutting member provided at an axial end of a driving roll or the like, the end of the endless belt is damaged. In addition to shortening the life of the endless belt, it is not possible to completely prevent the endless belt from moving in the axial direction, so it is not possible to sufficiently prevent the endless belt from shifting or meandering in the axial direction. Had.

Therefore, rather than mechanically preventing the endless belt from shifting or meandering in the axial direction by using an abutting member or the like, a method for detecting the endless belt's shifting or meandering and controlling the same is used as a method. There is a steering system in which a belt supporting roll is steered in accordance with the shift or meandering of the belt.

Japanese Patent Application Laid-Open No. 3-28816 discloses a technique related to a steering system in which a belt supporting roll of this type is steered in accordance with the deviation and meandering of the belt.
No. 7, JP-A-8-123120, JP-A-8-123120
-217302 or JP-A-9-169449
Publications have already been proposed.

In the technique disclosed in Japanese Patent Application Laid-Open No. 3-288167, the belt is supported by a drive roll for driving the endless belt, a support roll for supporting the belt, and a correction roll for adjusting the belt tension. Detecting deviation or meandering by detecting a sign provided on the endless belt with a detecting means such as a CCD (Charge Coupled Device), and moving the rotation center axis of the correction roll based on an output signal of the detecting means; By adjusting the belt tension by the movement of the rotation center axis, the belt is shifted or meandering is corrected.

A color image forming apparatus according to the above-mentioned Japanese Patent Application Laid-Open No. 8-123120 discloses a color image forming a color image by superimposing a plurality of color toner images on an image carrying belt supported by a plurality of rolls. A belt guide member that contacts an edge of the image carrying belt to restrict the lateral movement of the image carrying belt toward the edge, and a movement that detects an amount of lateral movement of the image carrying belt in the forming apparatus. An amount detecting unit, a calculating unit that calculates a pressing force received by the image guide belt from the belt guide member according to the moving amount, and calculates a difference between the pressing force and a reference pressing force. And control means for controlling the amount of movement of the image carrying belt to set the pressing force in a predetermined range.

Further, the belt drive control device disclosed in Japanese Patent Application Laid-Open No. Hei 8-217302 is an endless belt drive control device provided in an image forming apparatus or the like. A belt support device including a belt meandering correction device that controls the traveling direction of the belt by swinging the belt, a belt position detection unit that detects the belt position, and a belt meandering direction based on data of the belt position detection unit. A calculation / control means for calculating and controlling the meandering speed; and a control signal output means for outputting a control signal to a belt meandering control device based on data of the calculation / control means, to detect and control the meandering of the belt. At a time interval T.

Further, the belt drive control device according to the above-mentioned Japanese Patent Application Laid-Open No. 9-169449 discloses a meandering belt in a belt width direction perpendicular to a conveying direction of a belt member that is stretched and driven to rotate by a plurality of rolls. In a belt drive control device that controls the meandering amount of the meandering of the belt member, meandering change amount, and detecting means for detecting at least two of meandering speed, correcting means for correcting the meandering of the belt member, Control means for supplying a control signal corresponding to the detection result of the detection means to the correction means to correct the meandering of the belt member, wherein the control means is configured to control the at least two detection values respectively. The control parameter is changed when the value falls below a predetermined value set correspondingly.

[0013]

However, the above-mentioned prior art has the following problems. That is, JP-A-3-288167 and JP-A-8-188167 described above.
In the case of the technology disclosed in JP-A-123120, JP-A-8-217302 or JP-A-9-169449, the mark provided on the endless belt is indicated by CC.
D (charge-coupled device), the amount of movement of the endless belt in the lateral direction is detected by the movement amount detection means, and the position of the belt is detected by the belt position detection means. The meandering direction and meandering speed of the belt are calculated and controlled by the calculating and controlling means based on the data of the detecting means, and at least two of the meandering amount, meandering change amount and meandering speed of the meandering of the belt member are detected by the detecting means. By detecting, the rotation center axis of the correction roll is moved based on an output signal from the detection means, the movement amount detection means, or the calculation / control means, and the belt tension is adjusted by the movement of the rotation center axis. Thus, the belt is configured to correct the deviation and meandering of the belt.

However, in the case of the above prior art,
When assembling an image forming apparatus using an endless belt or replacing the endless belt, when attaching the endless belt to a plurality of rolls including a driving roll, a belt unit that supports the endless belt is used. After tilting,
It is necessary to attach the endless belt to the belt unit after moving any of the plurality of rolls that stretch the endless belt so that no tension acts on the endless belt. At that time, when the endless belt is mounted on the belt unit, as shown in FIG. 13, the position of the endless belt in the width direction orthogonal to the process direction is at a position deviating from a predetermined control position. However, since the marking provided on the endless belt and the end of the endless belt cannot be detected by the detecting means or the belt position detecting means, the endless belt can be properly positioned even if the correction roll or the like is steered. The end of the endless belt may come into contact with the housing of the cleaning device, etc., causing the end edge of the endless belt to bend or be damaged, shortening its life, or causing damage to the endless belt. There was a problem of causing.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and has as its object to assemble an image forming apparatus using an endless belt or to provide an endless belt. An image forming apparatus capable of always attaching an endless belt to a proper position of a plurality of rolls including a drive roll at the time of belt replacement or the like and preventing the endless belt from being damaged or damaged. Is to provide.

[0016]

According to a first aspect of the present invention, in an image forming apparatus using an endless belt stretched by a plurality of rolls, an endless belt is mounted on the plurality of rolls. A positioning member for positioning the endless belt, and the positioning member is configured to retreat to a position where the endless belt is not in contact with the endless belt during image formation.

In the invention described in claim 2, the positioning member moves to the positioning position of the endless belt in conjunction with the operation of moving the plurality of rolls to the mounting position of the endless belt. In addition, in conjunction with the operation of moving the plurality of rolls to the image forming position, the plurality of rolls are retracted to a position where they are not in contact with the endless belt.

[0018]

In the image forming apparatus according to the present invention, when the endless belt is mounted, for example, the belt tension roll is inclined obliquely, the tension of the roll is released, and the endless belt is detached. Further, the meandering prevention control of the belt is controlled by detecting a sign provided on the belt by a detecting means such as a CCD. When the belt is mounted, if an operation such as inclining the belt tension roll is performed so that the belt can be mounted in an area where the belt meandering prevention control sign can be detected, the positioning member on the back side in the belt axial direction is used. This allows the belt to be easily attached.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1 FIG. 3 shows a color electrophotographic copying machine as an image forming apparatus according to Embodiment 1 of the present invention.

In FIG. 3, reference numeral 1 denotes a photosensitive drum as a latent image carrier.
The photosensitive drum 1 is rotationally driven at a predetermined speed along a direction indicated by an arrow A by a driving unit (not shown).
An electrostatic latent image corresponding to the image information is formed by a known electrophotographic process such as a charging unit. The photosensitive drum 1
Is uniformly charged to a predetermined potential by a scorotron 2 for primary charging, and an image is scanned and exposed by an image exposing means such as a ROS (not shown). An electrostatic latent image corresponding to the image is formed. Around the photosensitive drum 1, four developing units 3, 4, 5, and 6 corresponding to each color of black (Bk), yellow (Y), magenta (M), and cyan (C) are arranged. The electrostatic latent image formed on the surface of the photosensitive drum 1 is developed by any one of the four developing units 3, 4, 5, and 6, and becomes a toner image T of a predetermined color. . Therefore, if the electrostatic latent image formed on the photosensitive drum 1 corresponds to a yellow image, yellow (Y)
Is developed by the yellow developing device 4 containing the toner of the type described above, and a yellow toner image is formed on the photosensitive drum 1.

The toner images formed on the photosensitive drum 1 are sequentially and multiplexly transferred onto an intermediate transfer belt 8 of an intermediate transfer belt unit 7 disposed below the photosensitive drum 1. The intermediate transfer body belt unit 7 includes an intermediate transfer body belt 8 as an endless belt. The intermediate transfer body belt 8 includes a driving roll 9 for driving the intermediate transfer body belt 8 and an intermediate transfer body. A tension roll 10 for controlling the tension of the belt 8 to be constant, an opposing roll (back-up roll) 11 for secondary transfer, and a driven roll 12 are stretched around in the direction of the arrow B at the same speed as the photosensitive drum 1. It is wrapped around so as to circulate along it.

The toner image formed on the photosensitive drum 1 is transferred to the photosensitive drum 1 at a primary transfer position where the photosensitive drum 1 contacts the intermediate transfer belt 8.
Is transferred onto the surface of the intermediate transfer belt 8. At this primary transfer position, on the back side of the intermediate transfer body belt 8,
A transfer roll 13 for primary transfer is provided, and the toner image on the photosensitive drum 1 is electrostatically attracted onto the intermediate transfer belt 8 by the primary transfer roll 13 to which a bias voltage is applied. Transcribed.

When a single color image is formed, the toner image primarily transferred on the intermediate transfer belt 8 is secondarily transferred to the recording medium 14 immediately. In the case of forming an image, the steps of forming a toner image on the surface of the photosensitive drum 1 and primary transferring the toner image onto the intermediate transfer belt 8 are repeated for a predetermined number of colors. For example, when a full-color image is formed by superimposing four color toner images, four color toner images of black, yellow, magenta, and Sian are sequentially formed on the photoreceptor drum 1 for each rotation. The toner images are sequentially primary-transferred onto the intermediate transfer body belt 8. On the other hand, the intermediate transfer belt 8 rotates at the same cycle as the photosensitive drum 1 while holding the first primary-transferred black toner image. The yellow, magenta, and cyan toner images are sequentially and multiplexly transferred for each rotation.

The toner image T primary-transferred onto the intermediate transfer belt 8 in this manner moves to a secondary transfer position facing the conveyance path of the recording medium 14 with the rotation of the intermediate transfer belt 8. Is conveyed. At the secondary transfer position, a semiconductive secondary transfer transfer roller 15 is provided with an intermediate transfer belt 8.
And the toner image T transferred onto the intermediate transfer belt 8 is secondarily transferred onto the recording medium 14. The recording medium 14 is housed in a paper feed tray 16 and is fed by a feed roll 17 at a predetermined timing.
Paper is fed from the paper feed tray 16. This paper feed tray 1
The recording medium 14 fed from the recording medium 6
Is temporarily stopped, and is conveyed to the secondary transfer position in synchronization with the toner image T transferred on the intermediate transfer belt 8 by the registration roll 18 which is rotated and driven at a predetermined timing. . At the secondary transfer position, on the back side of the intermediate transfer belt 8 facing the secondary transfer roll 15, a backup roll 11 serving as a counter electrode of the secondary transfer roll 15 is provided. The toner image transferred onto the intermediate transfer belt 8 is collectively electrostatically transferred onto the recording medium 14 at the secondary transfer position by applying a voltage having a polarity opposite to the charge polarity of the toner by the metal roll 19 to the toner image. Is done.

The dirt adhering to the surface of the secondary transfer roll 15 is removed by the cleaning blade 20 over the entire circumference thereof, thereby preventing the dirt on the back surface of the recording medium 14.

The recording medium 1 onto which the toner image has been transferred
4 is separated from the intermediate transfer body belt 8 by its own rigidity and the charge removing action of the guide plate 21,
The toner image is fixed on the recording medium 14 by heat and pressure by the fixing device 23 and discharged onto a discharge tray (not shown) outside the apparatus. On the other hand, residual toner is removed from the intermediate transfer belt 8 after the secondary transfer process of the toner image is completed by the belt cleaner 24.

The secondary transfer roll 15 and the belt cleaner 24 are disposed so as to be able to contact and separate from the intermediate transfer belt 8, and when a color image is formed, the toner image before the final color is formed. Transfer roll 15 and belt cleaner 2
These members are separated from the intermediate transfer belt 8 until they pass through the belt 4.

The intermediate transfer belt 8 is made of a synthetic resin such as polyimide, polycarbonate, polyester, polypropylene or polyethylene terephthalate or various synthetic rubbers containing an appropriate amount of carbon black or the like, and has a volume resistivity of 10 ⁶ to 10 ⁶ . Formed to be 10 ¹⁵ Ω · cm,
The thickness is set to, for example, 0.1 mm.

Further, as the backup roll 11, an EPDM-coated roll having a two-layer structure in which the outer periphery of a metal core is coated with an inner foamed elastic layer and an outer conductive layer is used. The outer conductive layer of the backup roll 11 is a semiconductive EPDM (ethylene propylene diene rubber) foamed rubber in which carbon black is dispersed at 15 to 35 wet%, and the thickness of the surface layer is, for example, 0.5 to
It is set to 1.5 mm. The surface resistivity of the backup roll 11 is controlled in a resistance range of 10 ⁷ to 10 ¹⁰ Ω / □. The metal roller 19 is brought into contact with the backup roller 11 configured as described above, and a predetermined voltage having a polarity opposite to that of the toner is applied to the metal roller 19 to generate a transfer electric field using the secondary transfer roll 15 as a counter electrode. It is configured to be.

The secondary transfer roll 15 has a thickness of 5 to 20 μm with a skin layer interposed between a core metal and a core layer made of a foamed EPDM material in which carbon black coated around the core metal is dispersed. And a volume resistivity between the core metal and the coating layer of 10 ⁴ Ω · cm to 10 ⁶ Ω · cm.
And the roll hardness is set to 20 ° to 45 ° in Asuka C hardness. The cleaning blade 20 attached to the secondary transfer roll 15 is, for example, a blade made of urethane rubber.

By the way, in this embodiment, the positioning member is used for positioning the endless belt when the endless belt is mounted on a plurality of rolls. When the image is formed, the positioning member is an endless belt. It is configured to retreat to a position not in contact with the belt. Further, the positioning member moves to the positioning position of the endless belt and moves the plurality of rolls to the image forming position in conjunction with the operation of moving the plurality of rolls to the endless belt mounting position. It is configured to retreat to a position not in contact with the endless belt in conjunction with the operation.

That is, as shown in FIG. 4, the intermediate transfer belt unit 7 of the color electrophotographic copying machine has a unit main body 30 which can be pulled out to the front side with respect to the copying machine main body. The intermediate transfer belt 8 stretched by a drive roll 9, a tension roll 10, a backup roll 11, and a driven roll 12 is housed inside the unit body 30. The drive roll 9 and the tension roll 10 for stretching the intermediate transfer belt 8
Rolls such as are rotatably supported by a front frame 31 and a rear frame 32, and the rear frame 32 is provided around a fulcrum 34 on a rear side wall 33 of the unit body 30. It is rotatably mounted.

The intermediate transfer belt unit 7
Pulls out the unit main body 30 of the intermediate transfer body belt unit 7 toward the near side with respect to the copier main body when assembling the color electrophotographic copying machine or replacing the intermediate transfer body belt 8, and the like. Holding a handle 35 provided on a front-side frame 31 that supports a roll such as a drive roll 9 or a tension roll 10 that stretches the body belt 8;
As shown in FIG. 1 and FIG. 5, the intermediate transfer belt 8 can be attached and detached by lifting it upward.

Further, the intermediate transfer body belt unit 7
Can manually release the tension applied to the tension roll 10 to release the tension applied to the intermediate transfer belt 8.
The attachment and detachment of the intermediate transfer belt 8 can be easily performed. The above tension roll 10
As shown in FIG. 6, both ends in the axial direction are rotatably supported by two arm members 36 and 37.
The arm members 36 and 37 are attached to the front frame 31 and the rear frame 32 so as to apply tension to the intermediate transfer belt 8 by compression springs 38 and 39. Then, the intermediate transfer body belt unit 7
Moves the adjusting plates 40, 41 to which one ends of the compression springs 38, 39 are attached by rotating the levers 44, 45 attached to the eccentric cams 42, 43, and the elastic force of the compression springs 38, 39 , The tension applied to the intermediate transfer belt 8 can be released. In FIG. 6, reference numeral 46 denotes a drive motor for performing steering control by inclining the rotation axis of the tension roll 10.

In this embodiment, when the intermediate transfer belt 8 is attached to the intermediate transfer belt unit 7,
A belt mounting assist mechanism 50 for positioning the intermediate transfer belt 8 in the width direction is provided.

This belt mounting assist mechanism 50 is similar to that shown in FIG.
As shown in FIG. 2, a first link 51 having one end rotatably attached to the frame 32 on the rear side of the intermediate transfer belt unit 7 is provided. The other end of the first link 51 is supported by a support plate (not shown) on the rear side wall 33 of the intermediate transfer belt unit 7 so as to be swingable about a fulcrum 52.
3 are connected at one end. On both end sides of the second link 53, compression springs 54 and 55 are interposed between the compression springs 54 and 55 and the rear side wall 33 of the intermediate transfer body belt unit 7.
The second link 53 is configured to be reliably swung with the movement of the rear frame 32 of the intermediate transfer body belt unit 7. Further, the other end of the second link 53 is connected to the positioning plate 5 via a support member 56.
7 are integrally attached.

The belt mounting assist mechanism 50
As shown in FIG. 1, the rear frame 32 and the front frame 31 that support the roll on which the intermediate transfer body belt 8 is stretched are tilted about a fulcrum 34 so that the rear frame 32 is tilted. A first link 51 attached to the frame 32 is pushed rearward as shown in FIG. 2, and a second link 53 rotatably connected to the other end of the first link 51 is a fulcrum. Swing about 52. As a result, the positioning plate 57 integrally attached to the other end of the second link 53 via the support member 56 allows the intermediate transfer belt 8 attached to the drive roll 9, the tension roll 10, and the like to move. It protrudes so as to be positioned at a predetermined position.

The belt mounting assist mechanism 50
As shown in FIG. 4, the rear frame 32 and the front frame 31 supporting the roll on which the intermediate transfer member belt 8 is stretched are pushed down to predetermined positions around the fulcrum 34, thereby The first link 51 attached to the rear frame 32 is returned to the front side, and the second link 53 rotatably connected to the other end of the first link 51 is centered on the fulcrum 52. Rocks. As a result, as shown in FIG. 4, the positioning plate 57 integrally attached to the other end of the second link 53 via the support member 56 is retracted to a position where it does not interfere with the image forming operation. It has become. The drive roll 9 and the driven roll 12 are provided with a mark 60 as a mark for positioning when the intermediate transfer belt 8 is mounted over the entire circumference.

With the above configuration, the color electrophotographic copying machine according to the present embodiment can be used as follows when assembling an image forming apparatus using an endless belt or replacing an endless belt. In addition, the endless belt can be always mounted at an appropriate position of a plurality of rolls including the drive roll, so that the endless belt can be prevented from being damaged or broken.

That is, in the above-mentioned color electrophotographic copying machine, the intermediate transfer belt 8 is moved to a roll such as a driving roll 9 or a tension roll 10 when the copying machine is assembled or when the intermediate transfer belt 8 is replaced. When stretched to
With the intermediate transfer belt unit 7 pulled out to the front side of the copying machine main body, as shown in FIG. 1, the grip 35 provided on the front frame 31 of the intermediate transfer belt unit 7 is lifted by hand. As a result, the intermediate transfer belt 8 can be attached or detached. At that time, the tension is applied to the intermediate transfer member belt 8 in the state as it is, and as shown in FIG. 6, the levers 44 and 45 are manually rotated to rotate the compression springs 38 and 39. Only after the tension is released, the tension roll 10 can move inward, so that no tension is applied to the intermediate transfer belt 8.

In this state, as shown in FIG. 1, the intermediate transfer belt 8 is wrapped around a drive roll 9 or a tension roll 10 from the right side in the figure to thereby transfer the intermediate transfer belt 8 to the intermediate transfer belt. It can be attached to the body belt unit 7.

At this time, the intermediate transfer belt unit 7
Rear frame 32 and front frame 31
Is tilted about the fulcrum 34 as shown in FIG. 1, the belt mounting assist mechanism 50 is operated, and the first link 51 attached to the rear side frame 32 is operated.
The second link 5 is pushed rearward as shown in FIG. 2 and rotatably connected to the other end of the first link 51.
3 swings about the fulcrum 52. As a result, the positioning plate 57 integrally attached to the other end of the second link 53 via the support member 56 allows the intermediate transfer belt 8 attached to the drive roll 9, the tension roll 10, and the like to move. It protrudes so as to be positioned at a predetermined position.

Therefore, when the intermediate transfer belt 8 is wrapped around a drive roll 9 or a tension roll 10, the rear side of the intermediate transfer belt 8 contacts the positioning plate 57 of the belt mounting assist mechanism 50. It is positioned within a predetermined range without touching and moving further rearward.

Therefore, after the intermediate transfer belt 8 is mounted as described above, the intermediate transfer belt 8 is
Even when the intermediate transfer belt 8 is driven to rotate, the intermediate transfer belt 8 is positioned within a predetermined range. Therefore, an index provided on the intermediate transfer belt 8 and an end of the belt 8 are detected by a detection unit (not shown). By doing so, the deviation and meandering of the intermediate transfer belt 8 can be controlled, and it is possible to reliably prevent the intermediate transfer belt 8 from being damaged or damaged.

The belt mounting assist mechanism 50
If the length of the intermediate transfer belt 8 in the process direction is relatively short, one may be provided at the center of the intermediate transfer belt 8 in the process direction. When the length is long, it is of course also possible to provide them at both ends in the process direction.

Second Embodiment FIG. 7 shows a second embodiment of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals and described. The endless belt is not an intermediate transfer belt but a transfer material transport belt for transporting a transfer material.

The image forming apparatus according to the second embodiment
As shown in FIG. 7, four image forming units 101Bk, 101 for forming images of each color of black (Bk), yellow (Y), magenta (M), and cyan (C).
Y, 101M, and 101C. These four image forming units 101Bk, 101Y, 101M, 1
01C are arranged in parallel at a certain distance from each other. The above four image forming units 101Bk, 10
1Y, 101M, and 101C, a paper feed tray 10
Transfer materials 106 fed from 2, 103, 104 via a paper feeding system 105 are transported in a state of being electrostatically attracted, and these image forming units 101Bk, 101Y, 101
M and 101C are transferred to the transfer material 1
A transfer material transfer unit 107 for transferring the image onto the transfer material 06 is provided.

The transfer material transport unit 107 includes a transfer material transport belt 108 as an endless belt. The transfer material transport belt 108 includes a driving roll 109 for driving the transfer material transport belt 108 and a transfer roller 109. A tension roll 110 for controlling the tension of the material conveying belt 108 to be constant, an idler roll 111, and a driven roll 11
2 and is circulated so as to circulate along the direction of arrow B at the same speed as the photosensitive drum.

As shown in FIGS. 8 to 10, the transfer material transporting unit 107 of the color electrophotographic copying machine has a unit main body 113 which can be pulled out to the front side with respect to the copying machine main body. Inside the unit body 113, a driving roll 109 and a tension roll 110,
A transfer material transport belt 108 stretched by an idler roll 111 and a driven roll 112 is stored. Rolls such as a drive roll 109 and a tension roll 110 that stretch the transfer material transport belt 108 are rotatably supported by a front-side frame 114 and a rear-side frame 115. ,
A fulcrum 117 is attached to the rear side wall 116 of the unit body 113.
It is attached so as to be rotatable around.

Then, the transfer material transport unit 107
Pulls out the unit body 113 of the transfer material transport unit 107 toward the front side with respect to the copy machine body when assembling the color electrophotographic copying machine or replacing the transfer material transport belt 108, and transfers the transfer material. By holding a handle 118 provided on a front-side frame 114 that supports a roll such as a drive roll 109 or a tension roll 110 that stretches the belt 108, and lifts it upward as shown in FIGS. 11 and 12, The transfer material transport belt 108 can be attached and detached.

In the second embodiment, as shown in FIG. 10, a transfer material transport belt 108 is mounted on the transfer material transport unit 107 at both ends in the process direction on the rear side of the transfer material transport unit 107. In this case, a belt mounting assist mechanism 50 for positioning the transfer material conveying belt 108 in the width direction is provided. As shown in FIG. 2, the belt mounting assist mechanism 50 has the same configuration as that of the first embodiment.

Other configurations and operations are the same as those of the first embodiment, and therefore, description thereof will be omitted.

[0054]

As described above, according to the present invention,
When assembling an image forming apparatus using an endless belt or replacing an endless belt, the endless belt can be always mounted at an appropriate position on a plurality of rolls including a driving roll, and the endless belt can be mounted. An image forming apparatus capable of preventing the belt from being damaged or damaged can be provided.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a main part of an image forming apparatus according to Embodiment 1 of the present invention;

FIG. 2 is a configuration diagram showing a belt mounting assist mechanism of the image forming apparatus according to Embodiment 1 of the present invention.

FIG. 3 is a configuration diagram showing a color electrophotographic copying machine as an image forming apparatus according to Embodiment 1 of the present invention.

FIG. 4 is a configuration diagram illustrating a main part of the image forming apparatus according to Embodiment 1 of the present invention;

FIG. 5 is an explanatory perspective view showing an attaching / detaching operation of the intermediate transfer member belt.

FIG. 6 is a perspective view showing a tension roll support mechanism.

FIG. 7 is a configuration diagram showing a color electrophotographic copying machine as an image forming apparatus according to Embodiment 2 of the present invention.

FIG. 8 is a perspective view showing an attaching / detaching operation of the transfer material conveying belt.

FIG. 9 is a front configuration diagram showing a support mechanism for a transfer material conveying belt.

FIG. 10 is a plan view showing a support mechanism of the transfer material conveying belt.

FIG. 11 is a cross-sectional configuration diagram illustrating an attaching / detaching operation of a transfer material conveying belt.

FIG. 12 is a cross-sectional configuration diagram illustrating an attaching / detaching operation of a transfer material conveying belt.

FIG. 13 is an explanatory perspective view showing an attaching / detaching operation of the intermediate transfer member belt.

[Description of Symbols] 7: Intermediate transfer belt unit, 8: Intermediate transfer belt, 9: Drive roll, 10: Tension roll, 50:
Belt mounting assist mechanism (belt positioning member).

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Keiji Yamamoto, Inventor Fuji Xerox Co., Ltd. 2274 Hongo, Ebina City, Kanagawa Prefecture (72) Inventor Naoto Yoshino 2274 Hongo, Hongo Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd. (72) Inventor Tatsuya Soga 2274 Hongo, Ebina-shi, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Naoto Nishi 2274 Hongo, Ebina-shi, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Shinka Komatsu 2274 Hongo, Ebina-shi, Kanagawa Prefecture Address Fuji Xerox Co., Ltd. (72) Inventor Takashi Kawabata 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd. (72) Inventor Norio Hokari 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd.F-term ( Reference) 2H032 BA01 BA09 BA18 BA23 2H035 CA05 CB06 CD03 CD05 CD11 CD15 3F049 AA03 DA03 DB02 LA04 LB03

Claims (2)

[Claims] 1. An image forming apparatus using an endless belt stretched by a plurality of rolls, a positioning member for positioning the endless belt when the endless belt is mounted on the plurality of rolls. An image forming apparatus, wherein the positioning member is retracted to a position not in contact with the endless belt during image formation. 2. The positioning member moves to a positioning position of the endless belt in conjunction with an operation of moving the plurality of rolls to a mounting position of the endless belt, and moves the plurality of rolls to an image forming position. The image forming apparatus according to claim 1, wherein the image forming apparatus is configured to retreat to a position where the endless belt is not in contact with the endless belt in conjunction with the operation of moving the endless belt.