JPH06255826A - Image forming device - Google Patents

Abstract

(57) [Abstract] [Purpose] The frictional force between the transfer material conveyance belt and the meandering detection member is always kept constant without being affected by scattered toner or paper dust, and reliable deviation control of the conveyance belt is performed. (EN) Provided is an image forming apparatus capable of maintaining a state and performing good image formation without color misregistration. A belt deviation prevention mechanism 100 for preventing the transfer material conveying belt 12 from meandering includes a belt cleaning device 110 for cleaning an area including a contact area of the transfer material conveying belt 12 with a meandering detection member 40. The contact state between the meandering detection member 40 and the transfer material conveying belt 12 can be always kept constant without being affected by the scattered toner or paper dust, and malfunction of the meandering regulation roller 32 can be prevented. This allows
It is possible to maintain a reliable offset control state of the transfer material transport belt 12 and form an excellent image without color misregistration.

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 a color copying machine or a business color copying machine, which forms an image on a transfer material such as paper using a plurality of photoconductors,
More specifically, the present invention relates to an image forming apparatus in which a belt deviation preventing means for preventing deviation of a transfer material conveying belt that conveys a transfer material is improved.

[0002]

2. Description of the Related Art In recent years, in response to the color orientation of offices,
Color copiers have appeared.

One of the systems of this color copying machine is a 4-tandem photosensitive drum tandem system. In this system, four photosensitive drums are arranged in parallel, and each photosensitive drum is
In this method, yellow, magenta, cyan, and black toners are used to form a toner image, and the toner images are sequentially transferred onto one transfer material to obtain a color image. Well, this 4
In the continuous tandem system, the transfer material placed on the transfer material conveying belt comes into contact with the four photoconductors one after another to transfer the toner image.

However, the transfer material is carried by the transfer material carrying belt to the four photoconductor drums. When the transfer material carrying belt is meandered, the transfer material is also meandered in accordance with the meandering, resulting in color shift. There is such a problem.

Conventionally, various methods have been devised as a meandering prevention method for the conveyance of a belt member used in an image forming apparatus. Among them, Japanese Patent Laid-Open No. 4-12
The method disclosed in Japanese Patent No. 1337 is a method in which one end of the meandering regulating roller is moved by the frictional force between the conveyor belt and the meandering detection member to mechanically control the deviation of the conveyor belt.

However, this system is premised on that the frictional force between the conveyor belt and the meandering detection member is always constant, and in an actual image forming apparatus, scattered toner and paper dust adhere to the inside of the conveyor belt. However, there has been a problem that the frictional force between the transfer material conveying belt and the meandering detection member changes with time, and sufficient deviation control of the conveying belt cannot be performed.

Further, in the system disclosed in Japanese Patent Laid-Open No. 4-121337, the meandering regulation roller is arranged so as to be in contact with the inside of the conveying belt, and in an actual image forming apparatus, a large belt occupying volume is used. However, there is a problem that the entire device becomes large.

[0008]

Conventionally, in this type of image forming apparatus, scattered toner and paper powder adhere to the inside of the transfer material conveying belt to cause a frictional force between the transfer material conveying belt and the meandering detection member. Change, and the deviation of the transfer material conveying belt cannot be sufficiently controlled, resulting in color misregistration.

Further, the meandering regulation roller is arranged so as to be in contact with the inside of the transfer material conveying belt, and in an actual image forming apparatus, there is a problem that a large belt occupying volume is required and the entire apparatus becomes large. there were.

The present invention has been made in view of the above circumstances. A first object of the present invention is that the friction between the transfer material conveying belt and the meandering detection member is always maintained without being affected by scattered toner and paper dust. An object of the present invention is to provide an image forming apparatus capable of forming a good image without color misregistration by maintaining a constant force and maintaining a positive bias control state of the transfer material conveying belt.

A second object of the present invention is to provide an image forming apparatus in which the meandering of the transfer material conveying belt can be restricted without requiring a large belt occupying volume and the apparatus can be made compact. To do.

[0012]

The present invention is, as a first means for achieving the above first object, provided corresponding to a plurality of image carriers that are sequentially arranged, and the respective image carriers are provided. A plurality of image forming means for respectively forming images on the top, a conveying means having a transfer material conveying belt for sequentially conveying the transfer material to each of the image carriers, and a corresponding one of the image carriers. A plurality of transfer means for respectively transferring the image formed on each of the image carriers to the transfer material transported by the transport means, and a belt piece for preventing deviation of the transfer material transport belt of the transport means An image forming apparatus comprising a deviation prevention means, wherein the belt deviation prevention means comprises a meandering regulation roller around which a transfer material conveyance belt of the conveyance means is stretched, and one end side of the meandering regulation roller. And for meandering regulation The meandering detection member, which is rotatably supported independently of each other and has a taper portion in contact with the end edge portion of the transfer material conveying belt, and a shaft end portion provided with the meandering detection member are rotated. The transfer material is conveyed to the meandering detection member, which has roller supporting means for supporting the meandering regulation roller so as to be displaceable in a direction orthogonal to the axis and a string-like member connected to the meandering detection member. A roller end displacing means for displacing the shaft end of the meandering regulation roller provided with the meandering detection member in a predetermined direction by converting the rotational motion into a linear motion when a rotational torque acts due to contact with the belt. A belt cleaning device that is provided upstream of the position of the meandering detection member in the running direction of the transfer material conveying belt and cleans a region including a contact region of the transfer material conveying belt with the meandering detection member. It is obtained by a structure formed by and means.

As a second means for achieving the above-mentioned first object, a plurality of images are provided corresponding to a plurality of image carriers that are sequentially arranged, and images are formed on the respective image carriers. Forming means, and a conveying means having a transfer material conveying belt for sequentially conveying the transfer material to each of the image carriers,
A plurality of transfer means provided corresponding to each of the image carriers and configured to respectively transfer an image formed on each of the image carriers to a transfer material transported by the transport means; An image forming apparatus comprising: a belt deviation prevention unit that prevents deviation of the transfer material conveyance belt, wherein the belt deviation prevention unit is a meandering regulation over which the transfer material conveyance belt of the conveyance unit is stretched. Detection roller, and one side of the meandering regulation roller, which is rotatably supported independently of the meandering regulation roller, and a portion in contact with the end edge portion of the transfer material conveying belt serves as a taper portion. A member, roller supporting means for supporting the meandering regulation roller so that an end of the shaft provided with the meandering detection member can be displaced in a direction orthogonal to the rotation axis, and the member is connected to the meandering detection member. String It has a timber, by converting a linear motion the rotary motion when rotation torque is applied by contact with the transfer material conveyance belt to the meandering detecting member,
Roller end portion displacement means for displacing the shaft end portion of the meandering regulation roller provided with the meandering detection member in a predetermined direction, and detection member cleaning means for cleaning the contact area of the meandering detection member with the transfer material transport belt. It is configured to include.

As means for achieving the above-mentioned second object, a plurality of image forming means are provided corresponding to a plurality of image carriers that are sequentially arranged, respectively, and that form an image on each of the image carriers. A transfer means having a transfer material transfer belt for sequentially transferring the transfer material to each of the image carriers, and a transfer material that is provided corresponding to each of the image carriers and is transferred by the transfer means. An image forming apparatus comprising a plurality of transfer means for respectively transferring an image formed on each of the image carriers and a belt deviation preventing means for preventing deviation of the transfer material conveying belt of the conveying means. The belt deviation preventing means includes a rotatable meandering regulation roller that comes in contact with the transfer material conveying belt of the conveying means from outside, and one side of the meandering regulation roller and independently of the meandering regulation roller. rotation A meandering detection member having a taper portion that is supported at the same time and is in contact with the end edge portion of the transfer material transport belt, and a direction in which a shaft end portion provided with the meandering detection member is orthogonal to the rotation axis. Roller supporting means for supporting the meandering regulation roller so that the meandering regulating roller can be displaced, and a cord-like member connected to the meandering detecting member, and the meandering detecting member is rotated by contact with the transfer material conveying belt. And a roller end displacing means for displacing the shaft end of the meandering regulation roller provided with the meandering detection member in a predetermined direction by converting its rotational movement into linear movement when torque is applied. It is what

[0015]

According to the image forming apparatus of the first means, the belt deviation preventing means for preventing the transfer material conveying belt from meandering cleans the area including the contact area of the transfer material conveying belt with the meandering detection member. By providing the cleaning means, the contact state between the meandering detection member and the conveyor belt can be always kept constant without being affected by the scattered toner and paper dust, and the malfunction of the meandering regulation roller can be prevented. As a result, it is possible to maintain a reliable deviation control state of the conveyor belt and form an excellent image without color misregistration.

According to the image forming apparatus of the second means, the belt deviation prevention means for preventing the meandering of the transfer material conveying belt is a detecting member cleaning means for cleaning the contact area of the meandering detecting member with the transfer material conveying belt. By including the above, it is possible to always keep the contact state between the meandering detection member and the conveyor belt constant without being affected by the scattered toner and paper dust, and prevent malfunction of the meandering regulation roller. As a result, it is possible to maintain a reliable deviation control state of the conveyor belt and form an excellent image without color misregistration.

According to the image forming apparatus of the third means, the belt deviation preventing means for preventing the meandering of the transfer material conveying belt makes the meandering detection roller contact from the outside of the transfer material conveying belt. The cross-sectional shape of the material conveying belt can be made small and the volume occupied in the device can be reduced. As a result, the entire device can be made compact.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. First, the first embodiment will be described with reference to FIGS.

FIG. 2 schematically shows the construction of a four-drum tandem type color copying machine as an image forming apparatus.
This color copying machine has four photosensitive drums 2Y, 2M, 2C and 2B as image bearing members which are sequentially arranged in parallel.
K and each of these photosensitive drums 2Y, 2M, 2C, 2BK
2Y, 2M, 2
A plurality of image forming means 150Y, 150M, 150C and 150BK for respectively forming images on C and 2BK, and a conveying means for sequentially conveying the transfer material 8 made of paper to the photosensitive drums 2Y, 2M, 2C and 2BK. 200 and the photoconductor drums 2Y, 2M, 2C, and 2BK, respectively, and the photoconductor drums 2Y, 2M, 2C, and 2B with respect to the transfer material 8 that is transported by the transport unit 200.
Transfer rollers 5Y, 5M, 5C, 5BK as a plurality of transfer means for respectively transferring the toner images formed on K.
Have.

Further, four sets of image forming means 150Y, 15
0M, 150C, 150BK are solid-state scanning heads 1Y, 1
M, 1C, 1BK, a recording unit including an equal-magnification imaging optical system, charging devices 3Y, 3M, 3C, 3BK, and a developing device 4
Y, 4M, 4C, 4BK, cleaning devices 6Y, 6
M, 6C, 6BK, static eliminator 7Y, 7M, 7C, 7BK
The image forming unit is composed of

Explaining the yellow image forming means 150Y, the solid scanning head 1Y outputs exposure light to the photosensitive drum 2Y in accordance with yellow image data sent from a print control unit (not shown). The solid-state scanning head 1Y has a structure in which minute light emitting portions are arranged at equal intervals on a line in the main scanning direction, and responds to an on-off signal sent from a print control portion according to a pattern to be printed. Then, by controlling the lighting of the individual light emitting portions of the line in the main scanning direction, the light is imaged on the photoconductor drum 2Y by an equal-magnification imaging optical system that images the light of the light emitting portions in a one-to-one manner. Perform exposure. Specifically, an LED head array with a resolution of 444 DPI was used for the solid-state scanning head 1Y, and a SELFOC lens array was used for the unity-magnification imaging optical system.

Around the photosensitive drum 2Y, a charging device 3Y for charging the surface of the photosensitive drum 2Y, a developing device 4Y,
A transfer device 5Y, a cleaning device 6Y, and a charge eliminating device 7Y are provided.

The photosensitive drum 2Y is rotationally driven at a peripheral speed of V0 by a drive motor (not shown). The surface of the photoconductor drum 2Y is charged by a charging device 3Y including a conductive charging roller provided in contact with the surface of the photoconductor drum 2Y. The charging roller is rotated by coming into contact with the surface of the photosensitive drum 2Y.

The surface of the photosensitive drum 2Y is formed of an organic photoconductor. This photoconductor usually has a high resistance, but has a property that the specific resistance of the light irradiation portion changes when light is irradiated. Then, the charged yellow
By irradiating the surface of the photoconductor drum 2Y with light corresponding to the yellow-printing pattern from the solid-state scanning head 1Y through an equal-magnification imaging optical system, an electrostatic latent image of the yellow-printing pattern is formed on the photoconductor drum 2Y. Formed on the surface.

The electrostatic latent image is an image formed on the surface of the photosensitive drum 2Y by charging, and the solid scanning head 1Y.
By the light irradiation from, the specific resistance of the surface to be irradiated of the photoconductor decreases, and the charged charges on the surface of the photosensitive drum 2Y flow,
On the other hand, it is a so-called negative latent image which is formed by remaining electric charge in the portion not irradiated with light from the solid-state scanning head 1Y.

The photoconductor drum 2 thus charged.
The light from the solid-state scanning head 1Y is imaged at the exposure position on Y, and the photosensitive drum 2Y on which the latent image is formed is rotated at the speed V0 to the developing position. Then, at this developing position, the latent image on the photosensitive drum 2Y is converted into a visible toner image by the developing device 4Y.

In the developing device 4Y, a yellow toner made of resin containing a yellow dye is prepared.
The yellow toner is triboelectrically charged by being agitated inside the developing device 4Y and has a charge of the same polarity as the electrostatic charge charged on the photosensitive drum 2Y. As the surface of the photoconductor drum 2Y passes through the developing device 4Y, the yellow toner is electrostatically attached only to the latent image portion where the charge is removed, and the latent image is developed by the yellow toner. (Reverse development).

The photosensitive drum 2Y on which the yellow toner image has been formed continues to rotate at the outer periphery V0, and at the transfer position, the transfer device 5Y moves the sheet on the conveyor belt 12 at a timing. The toner image is transferred onto the transfer material (paper) 8 of.

The paper feeding system comprises a pickup roller 9, a feed roller 10, and a registration roller 11.
The transfer material 8 lifted from the paper feed cassette 39 by the pickup roller 9 is conveyed by the feed roller 10 to the registration roller 11 one by one. The registration rollers 11 feed the transfer material 8 onto the transfer material conveyance belt 12 after the transfer material 8 is repositioned. The peripheral speed of the registration roller 11 and the peripheral speed of the transfer material conveying belt 12 are the same as those of the photosensitive drum 2Y
The peripheral speed V0 is set to be constant. The transfer material 8 is sent to the transfer position of the photosensitive drum 2Y together with the transfer material conveying belt 12 at a speed V0 equal to that of the photosensitive drum 2Y while the transfer material 8 is partially held by the registration roller 11.

At the transfer position, the yellow-toner image on the photoconductor drum 2Y which is in contact with the transfer material 8 is separated from the photoconductor drum 2Y and transferred onto the transfer material 8 by the transfer device 5Y. A yellow toner image having a print pattern based on the print signal is formed on the transfer material 8.

The transfer device 5Y is composed of a transfer roller having semiconductivity. The transfer roller supplies an electric field having a polarity opposite to that of the potential of the yellow toner electrostatically attached to the photosensitive drum 2Y from the back side of the transfer material transport belt 12. This electric field is generated by the transfer material conveying belt 1.
2, and acts on the yellow-toner image on the photoconductor drum 2Y through the transfer material 8 and, as a result, the photoconductor drum 2Y.
The toner image is transferred to the transfer material 8.

The transfer material 8 on which the yellow toner image is transferred is sequentially supplied to the magenta image forming means 150M, the cyan image forming means 150C, and the black image forming means 150BK.

Incidentally, the magenta image forming means 150M, the cyan image forming means 150C, the black image forming means 15
The 0BK is composed of the same constituent members and functions in which the yellow (Y) in the yellow image forming unit 150Y described above is replaced with magenta (M), cyan (C), and black (BK). For simplification, description of these image forming means is omitted.

The transfer material 8 on which the color-superimposed image is formed is fed to the fixing device 13 by sequentially passing through the yellow transfer position, the magenta transfer position, the cyan transfer position, and the black transfer position.

The fixing device 13 is composed of a heat roller incorporating a heater, and heats only the toner image on the transfer material 8 due to the electric charge,
The color-superposed toner images are melted and permanently fixed to the transfer material 8. The transfer material 8 on which the fixing is completed is carried out to the paper discharge tray 15 by the sending roller 14.

On the other hand, the photoconductor drums 2Y, 2M, 2C and 2BK of the respective colors that have passed the transfer position are kept at the outer peripheral speed V.
The cleaning devices 6Y, 6M, 6 are driven to rotate at 0.
The residual toner and paper dust are cleaned by C and 6BK, and the surface potential is made constant by the static elimination lamps of the static eliminators 7Y, 7M, 7C and 7BK, and the charging devices 3Y, 3M, 3C and 3BK are again charged as necessary. Enter the series of processes from.

The transfer material carrying belt 12 carrying the transfer material 8 has an endless structure and has a fixing device 13.
Side driving roller 16 and driven roller 17 on the transfer material supply port side
Held by and. The driving roller 16 receives a driving force from a driving motor (not shown) and is driven so that the outer peripheral speed V0 of the photosensitive drum and the outer peripheral speed of the belt become constant.

On the other hand, the driven roller 17 has a mechanism capable of moving in a direction parallel to the transfer material conveying direction on shaft portions on both sides of the roller, and the transfer material conveying belt 12 is compressed by a compression spring 18 in the direction opposite to the transfer material conveying direction. Pressed to apply a tensile load to. A mechanism that allows the driven roller 17 to move in a direction parallel to the transfer material conveyance direction is a long hole 39 (see FIG. 1) provided in the frame 24, which slides on the elongated hole 39 and rotates the driven roller 17. The driven roller holding member 21 is made possible.

After the transfer material 8 is sent to the fixing device 13, the transfer material conveying belt 12 is cleaned by the belt cleaning device 22 to remove the residual toner and paper dust adhering to the surface of the belt. To transport.

In the case of monochromatic printing, the above-mentioned arbitrary monochromatic recording portion and image forming portion perform image formation. At this time, the recording unit and the image forming unit other than the selected color do not operate. Next, the conveying means 200 for conveying the transfer material 8 will be described with reference to FIG.

The conveying means 200 is stretched over the belt driving roller 16, the driven roller 17 and the meandering regulation roller 32 which are provided in parallel, and the intermediate portion is the photosensitive drum 2 described above.
The endless transfer material transport belt 12 is stretched to face the Y, 2M, 2C, and 2BK.

The drive roller 16 is disposed in a hole provided in the belt unit frame 24 via a drive roller bearing 19 in a rotatable state and in a state where the rotation center axis position is fixed.

The driven roller 17 is rotatably moved in the direction perpendicular to the center axis of rotation of the drive roller 16 via a driven roller bearing 21 fitted in an elongated hole 39 provided in the belt unit frame 24. It is arranged in a possible state. This is because the long hole 39 provided in the belt unit frame 24 is set so as to have the long axis in the direction perpendicular to the rotation center axis of the drive roller 16.

On the other hand, the driven roller bearing 2 of the driven roller 17
1, the compression spring 18 applies a force in the long axis direction of the long hole 39. As a result, the conveyor belt 1
2 is to be tensioned.

The transfer material conveying belt 12 is prevented from being biased by a belt biasing prevention mechanism 100 as a belt biasing prevention means including the meandering regulation roller 32.

As shown in FIG. 1, the belt deviation preventing mechanism 100 includes a meandering restricting roller 32 around which the transfer material conveying belt 12 is stretched, and one meandering restricting roller 32 at one end of the meandering restricting roller 32. A meandering detection member 40 that is independently rotatably supported and has a taper portion 40A at a portion in contact with the edge portion of the transfer material transport belt 12.
The roller support mechanism 105 is provided as a roller support means for supporting the meandering regulation roller 32 so that the shaft end portion provided with the meandering detection member 40 can be displaced in a direction orthogonal to the rotation axis.

Further, it has a string-like member 34 connected to the meandering detection member 40, and when a rotation torque acts on the meandering detection member 40 due to contact with the transfer material conveying belt 12, the rotation motion is converted into a linear motion. Thus, the roller end portion displacement mechanism 106 is provided as a roller end portion displacement means for displacing the shaft end portion of the meandering regulation roller 32 provided with the meandering detection member 40 in a predetermined direction.

Further, in this embodiment, the transfer material conveying belt 1 is located farther than the disposition position of the meandering detection member 40.
2 is located on the upstream side in the traveling direction of the transfer material conveying belt 12
The belt cleaning device 110 as a belt cleaning means for cleaning an area including a contact area with the meandering detection member 40 is attached. Further, the belt deviation prevention mechanism 1
00 will be described in detail.

One end portion of the meandering regulation roller 32 is rotatably fitted to a meandering regulation roller fixed bearing 37 fixed to the belt unit frame 24. Since the bearing portion of the meandering regulation roller fixed bearing 37 has a conical shape,
The meandering regulation roller 32 can be inclined in a conical shape around the roller bearing 37.

At the other end of the meandering regulation roller 32, a meandering detection member 40 is fitted in a freely rotatable state, and the tip end thereof is held by a meandering regulation roller sliding bearing 38. That is, the meandering detection member 40
Is free to rotate on the meandering regulation roller 32, and the meandering regulation roller 32 is composed of a meandering regulation roller fixed bearing 37 which is a bearing and a meandering regulation roller sliding bearing 38 which is a bearing. It is rotatably supported.

The meandering regulation roller slide bearing 38 is fitted in an elongated hole 33 provided in the belt unit frame 24, and the elongated hole 33 is formed in the driving roller 16 and the driven roller 17.
Has a major axis in a direction parallel to a plane including the rotation center axis of the. Therefore, the meandering restriction roller 32 is in a state in which the side of the meandering restriction roller sliding bearing 38 is movable in a direction parallel to the plane including the rotation center axes of the drive roller 16 and the conveyor belt driven roller 17.

A compression spring 35 is attached to the meandering regulation roller sliding bearing 38 in the major axis direction of the elongated hole 33, and a compression force is applied from the driven roller 17 side. Further, the meandering detection member 40 has a string-shaped member 34 wound from the upper side with the driven roller 17 side as a fixed end. Next, the operation of the belt deviation prevention mechanism 100 configured as described above will be described with reference to FIG. 1 and FIGS.

The transfer material conveying belt 12 is conveyed in the direction of arrow A in the figure, that is, from the driven roller 17 side to the drive roller 16 side. The transfer material transport belt 12 runs in a state where a part of the transfer material transport belt 12 is in contact with the conical tapered portion 40A of the meandering detection member 40 having a combination of a cylindrical shape and a conical shape.

Since the cord-like member 34 is wound around the columnar portion 40B from above, the meandering detection member 40 is in a sliding state when the transfer material transport belt 12 runs. In this state, the length of the cord-like member 34 and the compression spring 3 are previously set.
The force of No. 5 is adjusted so that the meandering regulation roller is in a constant state. At this time, when a force to rotate the meandering detection member 40 is generated by the frictional force between the meandering detection member 40 around which the string-shaped member 34 is wound and the transfer material transport belt 12, the string-shaped member 34 meanders by this force. A force to wind around the detection member 40 is generated, and the force causes the meandering detection member 40 side of the meandering regulation roller 32 to move the driven roller 1.
The force to move to the 7 side is generated.

When the transfer material conveying belt 12 has no deviation, as shown in FIGS. 3 and 4, the force of the meandering regulation roller 32 to move to the driven roller 17 side and the meandering regulation roller slide. The meandering regulation roller 32 is in a state in which the compression spring 35 attached to the dynamic bearing 38 in the long axis direction of the elongated hole 33 balances the forces for suppressing it.
Is spinning.

Now, assuming that the transfer material conveying belt 12 is offset on the left side (the lower side in FIG. 5) in the traveling direction in the drawing, the transfer material conveying belt 12 is displaced on the left side in the traveling direction.
A wider portion of the taper portion 40A of the meandering detection member 40 comes into contact with the transfer material transport belt 12.

Transfer material conveying belt 1 having a constant friction coefficient
By increasing the contact area between 2 and the meandering detection member 40,
A force that further rotates the meandering detection member 40 is generated,
Due to this force, a force is generated that causes the cord to further wind around the meandering detection member 40, and a force that causes the meandering detection member 40 to further move to the driven roller 17 side is generated by this force.

The force by which the meandering regulating roller 32 further moves toward the driven roller 17 and the compression spring 35 attached to the meandering regulating roller sliding bearing 38 in the longitudinal direction of the elongated hole 33 will suppress this. The meandering regulation roller 32 rotates in a state in which the forces to be set are balanced, but when the transfer material transport belt 12 approaches the left side in the traveling direction in this way,
The force by which the meandering restriction roller 32 further moves toward the driven roller 17 becomes larger than in the initial state, and as a result, the meandering detection member 40 side of the meandering restriction roller 32 moves toward the driven roller 1.
The force is in equilibrium with a slight movement to the 7 side.

That is, as shown in FIGS. 5 and 6, in the meandering regulation roller 32, the meandering detection member 40 side of the meandering regulation roller 32 is somewhat closer to the driven side roller 17 with respect to the traveling direction of the transfer material conveying belt 12. It will be tilted.

At this time, since the meandering regulation roller 32 is tilted, a traveling force F generated in a direction perpendicular to the rotation center axis of the roller is applied to the transfer material transport belt 12. During the actual movement, this traveling force F acts on the belt conveying direction FH and the force decomposed in the direction FV perpendicular to the belt conveying direction.

The direction FV of the force decomposed in the direction perpendicular to the belt conveying direction is a biased direction, that is, a force in the direction opposite to the force to move to the left side in the belt traveling direction. Offset to the left is corrected. When the deviation is corrected by this force FV, the contact area between the transfer material conveyance belt 12 and the meandering detection member 40 gradually decreases, and the initial state is restored. As a result, the meandering regulation roller 32 also returns to the initial state.

If the transfer material transport belt 12 is offset to the right in the traveling direction (upper side in FIG. 7) in the figure, the transfer material transport belt 12 is displaced to the right in the traveling direction.
The narrower portion of the tapered portion 40A of the meandering detection member 40 comes into contact with the transfer material transport belt 12.

Transfer material conveying belt 1 having a constant friction coefficient
Since the contact area between the meandering detection member 40 and the meandering detection member 40 becomes small, the force that the meandering detection member 40 tries to rotate weakens,
This force weakens the force with which the cord-like member 34 further winds around the meandering detection member 40, and loses the initial compression force of the compression spring 35. As a result, the meandering detection member 40 side of the meandering regulation roller 32 is driven side roller. The state of equilibrium of the force is obtained when it is moved to the 16 side somewhat.

That is, as shown in FIGS. 7 and 8, in the meandering regulation roller 32, the meandering detection member 40 side of the meandering regulation roller 32 is somewhat closer to the drive side roller 16 side with respect to the traveling direction of the transfer material conveying belt 12. It will be tilted.

At this time, since the meandering regulation roller 32 is tilted, a traveling force F generated in a direction perpendicular to the rotation center axis of the roller is applied to the transfer material transport belt 12. During the actual movement, this traveling force F acts on the belt conveying direction FH and the force decomposed in the direction FV perpendicular to the belt conveying direction. The direction FV of the force decomposed in the direction perpendicular to the belt conveying direction is a direction opposite to the biased direction, that is, the force to move to the right side in the belt traveling direction, and this force causes the force to move to the right side in the belt traveling direction. The deviation is corrected.

When the deviation is corrected by this force FV, the contact area between the transfer material conveying belt 12 and the meandering detection member 40 gradually increases and returns to the initial state. As a result, the meandering regulation roller 32 also returns to the initial state.

As described in detail above, the belt offset prevention mechanism 100 is a purely mechanical automatic control.
It is extremely superior to other belt offset control methods that use other sensors or motors in that the structure is simple and the cost is low.

However, since the position of the meandering regulation roller 32 is controlled by the dynamic friction between the transfer material conveying belt 12 and the meandering detection member 40, the scattered toner and paper dust generated inside the apparatus come into contact with the meandering detection member 40 and this. If it adheres to the belt area that changes and the rotation state of the meandering detection member 40 is changed or the friction value is changed, the meandering regulation roller 32 that changes the position accordingly does not function as in the initial state. .

Therefore, in this embodiment, the transfer material conveying belt 12 is positioned upstream of the position where the meandering detection member 40 is provided so that the scattered toner and paper dust are not adversely affected. Thus, a belt cleaning device 110 for cleaning an area including a contact area of the transfer material conveyance belt 12 with the meandering detection member 40 is additionally provided.

As the belt cleaning means 110, in this embodiment, as shown in FIGS. 1, 3 and 4, a PET film for cleaning a region including a region in contact with the meandering detection member 40 inside the transfer material transport belt 12 is used. And a cleaning hopper 42 for accommodating the toner and paper dust cleaned by the cleaning member 41A.

The cleaning member 41A is held in a state of being inclined from the inside of the transfer material conveying belt 12 toward the outside, and has a length up to the outside of the transfer material conveying belt 12. Then, the toner and the paper powder attached to the area including the contact area of the transfer material transport belt 12 with the meandering detection member 40 hits the cleaning member 41A and gradually moves on the transfer material transport belt 12 as the transfer material transport belt 12 travels. Transferring material transfer belt 12 automatically moved to the outside
It is designed to be discharged to the outside.

The cleaned and discharged toner and paper dust are collected by the cleaning hopper 42 disposed below the cleaning hopper 42 so that the inside of the apparatus is not contaminated. 9 to 14 show the belt cleaning device 11
0 shows different modified examples.

FIG. 9 shows a structure in which the transfer material conveying belt 12 is sandwiched between a blade-shaped cleaning member 41A made of PET film and a roller-shaped belt holding member 43B. The back side of the transport belt 12 firmly contacts the blade-shaped cleaning member 41A, and the cleaning efficiency is improved.

In this embodiment, since the blade-shaped belt holding member 43 is provided so as to bend in accordance with the belt traveling direction, the blade-shaped belt holding member 43 is firmly and without increasing the driving load of the transfer material conveying belt 12. Transfer material transport belt 1
2 can be held.

FIG. 10 shows a structure in which the transfer material conveying belt 12 is sandwiched by a blade-shaped cleaning member 41A made of a PET film and a roller-shaped belt holding member 43B. The back side of the transport belt 12 firmly contacts the cleaning member 41A, and the cleaning efficiency is improved.

FIG. 11 shows a structure in which the transfer material transport belt 12 is sandwiched between a brush-shaped cleaning member 41B and a blade-shaped belt holding member 43A made of PET film. The back side of 12 firmly contacts the brush-like cleaning member 41B, and the cleaning efficiency is improved.

FIG. 12 shows a brush-like cleaning member 41B and a roller-like belt holding member 43B.
The transfer material transport belt 12 is structured to be sandwiched between the transfer material transport belt 12 and the transfer material transport belt 12, and the back side of the transfer material transport belt 12 is firmly in contact with the cleaning member 41B to enhance the cleaning efficiency.

FIG. 13 shows a structure in which the transfer material conveying belt 12 is sandwiched between a roll brush-like cleaning member 41C and a brush-like holding member 43A made of PET film. The back side of the roller is a roll brush-like cleaning member 41C.
And the cleaning efficiency is improved.

FIG. 14 shows a roller brush-like cleaning member 41C and a roller brush-like holding member 43.
The transfer material transport belt 12 is sandwiched between B and B, and the back side of the transfer material transport belt 12 is firmly in contact with the roll brush-shaped cleaning member 41C, and the cleaning efficiency is improved.

As described above, in this embodiment,
The transfer material transport belt 1 is located farther than the arrangement position of the meandering detection member 40
2 is located on the upstream side in the traveling direction of the transfer material conveying belt 12
The belt cleaning device 110 for cleaning the area including the contact area with the meandering detection member 40 is additionally provided. As a result, the dynamic friction coefficient between the transfer material conveyance belt 12 and the meandering detection member 40 is always kept constant without being adversely affected by the scattered toner and paper dust, and stable meandering control that is the same as the initial state is realized. Can be done.

FIGS. 15 and 16 show a detecting member for cleaning the area of the tapered portion 40A of the meandering detecting member 40 by the belt deviation preventing mechanism 100 as a belt deviation preventing means for preventing the transfer material conveying belt from meandering. It has a configuration including a detection member cleaning device 120 as a cleaning unit.

In FIG. 14, the blade-shaped cleaning member 41A made of PET film is brought into contact with the tapered portion 40A of the meandering detection member 40. Then, when the meandering detection member 40 rotates along with the meandering of the transfer material transport belt 12, the attached toner and paper dust are cleaned by the blade-shaped cleaning member 41A, and the cleaned toner and paper dust are collected in the cleaning hopper. It is collected in 42 so that the inside of the device is not polluted.

In FIG. 15, the roll brush-like cleaning member 41C is in contact with the taper portion 40A of the meandering detection member 40. The meandering detection member 4 is moved along with the meandering of the transfer material conveying belt 12.
When 0 rotates, the adhered toner and paper dust are cleaned by the roll brush-like cleaning member 41C, and the cleaned toner and paper dust are collected in the cleaning hopper 42 so that the inside of the apparatus is not polluted. . As the cleaning member, a brush,
Of course, it may be something other than a roll brush.

As described in detail above, by providing a member for cleaning the region in contact with the meandering detection member 40 and the transfer material conveying belt 12, that is, the boundary region of the tapered portion,
The dynamic friction coefficient between the transfer material conveyance belt 12 and the meandering detection member 40 is always kept constant, and stable meandering control that is the same as in the initial state can be realized. Next,
A second belt deviation prevention mechanism 130 as a belt deviation prevention means will be described with reference to FIGS. 17 to 23.

The belt deviation prevention mechanism 130 is configured to bring the meandering regulation roller 32 into contact with the transfer material conveying belt 12 from the outside.
The cross-sectional shape of the device can be made small in area, the volume occupied in the device can be reduced, and the entire device can be made compact.

This belt deviation prevention mechanism 130 is shown in FIG.
As shown in FIG. 7, the contact between the meandering regulation roller 32 and the transfer material conveying belt 12 is made from the outside of the transfer material conveying belt 12, and the winding of the cord-like member 34 around the columnar portion 40B of the meandering detecting member 40 is performed. Figure 1 shows the point of winding from the side.
Is different from the belt deviation preventing mechanism 100 described above with reference to FIG.

Therefore, the transfer material conveying belt 12 is conveyed in the direction of arrow A in the figure, that is, from the driven roller 17 side to the drive roller 16 side. The transfer material transport belt 12 is
The vehicle runs in a state where a part of the meandering detection member 40 is in contact with the conical tapered portion 40A. The meandering detection member 40 includes
Since the string-shaped member 34 is wound from the upper side, the transfer material transport belt 12 is in a sliding state when traveling. In this state, the length of the cord-shaped member 34 and the force of the compression spring 35 are adjusted in advance so that the meandering regulation roller 32 is in a constant state.

At this time, a frictional force between the meandering detection member 40 around which the cord-like member 34 is wound and the transfer material transport belt 12 generates a force that causes the meandering detection member 40 to rotate,
Due to this force, a force that causes the cord-shaped member 34 to wind around the meandering detection member 40 is generated. Due to this force, a force that causes the meandering detection member 40 side of the meandering regulation roller 32 to move to the drive roller 16 side is generated.

When the transfer material conveying belt 12 has no deviation, as shown in FIGS. 18 and 19, the meandering regulation roller 32 is moved toward the driven roller 17 and the meandering regulation roller 32. The meandering regulation roller 32 rotates in a state in which the compression spring 35 attached to the regulation roller sliding bearing 38 in the longitudinal direction of the elongated hole 33 balances the forces for suppressing it.

Now, assuming that the transfer material conveying belt 12 is deviated to the left in the traveling direction in the drawing (lower side in FIG. 20), the transfer material conveying belt 12 is displaced to the left in the traveling direction.
A wider portion of the taper portion 40A of the meandering detection member 40 comes into contact with the transfer material transport belt 12.

Transfer material conveying belt 1 having a constant friction coefficient
By increasing the contact area between 2 and the meandering detection member 40,
A force that further rotates the meandering detection member 40 is generated,
Due to this force, a force is generated that causes the cord to further wind around the meandering detection member 40, and a force that causes the meandering detection member 40 to further move to the driven roller 17 side is generated by this force.

The force by which the meandering regulating roller 32 further moves to the driven roller 17 side and the compression spring 35 attached to the meandering regulating roller sliding bearing 38 in the longitudinal direction of the long hole 33 will suppress this. The meandering regulation roller 32 rotates in a state in which the forces to be set are balanced, but when the transfer material transport belt 12 approaches the left side in the traveling direction in this way,
The force by which the meandering restriction roller 32 further moves toward the driven roller 17 becomes larger than in the initial state, and as a result, the meandering detection member 40 side of the meandering restriction roller 32 moves toward the driven roller 17 side.
The force is in equilibrium with some movement to the side.

That is, as shown in FIGS. 20 and 21, the meandering regulation roller 32 is arranged in the meandering detection member 40 of the meandering regulation roller 32 in the traveling direction of the transfer material conveying belt 12.
The side is slightly inclined to the driven roller 17 side.

At this time, since the meandering regulation roller 32 is tilted, the meandering regulation roller 3 is attached to the transfer material conveying belt 12.
A traveling force F generated in a direction perpendicular to the rotation center axis of 2 is applied. At the time of actual movement, this traveling force F is decomposed into a belt conveying direction FH and a direction FV perpendicular to the belt conveying direction. The direction FV of the force decomposed in the direction perpendicular to the belt conveying direction is a force in the direction that is biased, that is, in the direction opposite to the force that attempts to move to the left side in the belt traveling direction, and this force causes the force to move to the left side in the belt traveling direction. The deviation is corrected. When the deviation is corrected by this force FV, the contact area between the transfer material conveyance belt 12 and the meandering detection member 40 gradually decreases, and the initial state is restored. As a result, the meandering regulation roller 32 also returns to the initial state.

If the transfer material transport belt 12 is offset to the right in the traveling direction (upper side in FIG. 22), the transfer material transport belt 12 is displaced to the right in the traveling direction.
The narrower portion of the tapered portion 40A of the meandering detection member 40 comes into contact with the transfer material transport belt 12.

Transfer material conveying belt 1 having a constant friction coefficient
Since the contact area between the meandering detection member 40 and the meandering detection member 40 becomes small, the force that the meandering detection member 40 tries to rotate weakens,
This force weakens the force with which the cord-shaped member 34 further wraps around the meandering detection member 40, and loses the initial compression force of the compression spring 35. As a result, the meandering detection member 40 side of the meandering regulation roller 32 drives the drive roller 16 The force is in equilibrium with some movement to the side.

That is, as shown in FIG. 22 and FIG. 23, the meandering regulating roller 32 is arranged so that the meandering detecting member 40 of the meandering regulating roller 32 with respect to the traveling direction of the transfer material conveying belt 12.
The side is slightly inclined to the drive roller 16 side.

At this time, since the meandering regulation roller 32 is tilted, a traveling force F generated in a direction perpendicular to the rotation center axis of the roller is applied to the transfer material conveying belt 12. During the actual movement, this traveling force F acts on the belt conveying direction FH and the force decomposed in the direction FV perpendicular to the belt conveying direction. The direction FV of the force decomposed in the direction perpendicular to the belt conveying direction is a direction opposite to the biased direction, that is, the force to move to the right side in the belt traveling direction, and this force causes the force to move to the right side in the belt traveling direction. The deviation is corrected.

When the deviation is corrected by this force FV, the contact area between the transfer material conveying belt 12 and the meandering detection member 40 gradually increases, and the initial state is restored. As a result, the meandering regulation roller 32 also returns to the initial state.

As described above in detail, the second belt deviation preventing mechanism 130 is arranged so that the meandering regulation roller 32 is pressed from the outside of the transfer material conveying belt 12 to transfer the transfer material conveying belt. It can be used without increasing the crossover occupied area of 12. Further, it is a pure mechanical automatic control, and is very excellent in that the structure is simple and the cost is low as compared with the belt offset control method using other sensors or motors. In the above description of the embodiments, the same parts as those described above are designated by the same reference numerals, and detailed description thereof will be omitted. It is needless to say that the present invention can be modified in various ways without departing from the spirit of the present invention.

[0101]

The present invention has the following effects.

According to the image forming apparatus of the first aspect, the belt deviation preventing means for preventing the transfer material conveying belt from meandering,
By providing a belt cleaning unit that cleans the area including the contact area of the transfer material conveyance belt with the meandering detection member, the contact state between the meandering detection member and the conveyance belt is always constant without being affected by scattered toner or paper dust. Therefore, malfunction of the meandering regulation roller can be prevented. As a result, it is possible to maintain a reliable deviation control state of the conveyor belt and form an excellent image without color misregistration.

According to the image forming apparatus of the second aspect, the belt deviation preventing means for preventing the transfer material conveying belt from meandering,
By providing the detection member cleaning means for cleaning the contact area of the meandering detection member with the transfer material conveyance belt, the contact state between the meandering detection member and the conveyance belt is always kept constant without being affected by scattered toner and paper dust. It is possible to prevent malfunction of the meandering regulation roller. As a result, it is possible to maintain a reliable deviation control state of the conveyor belt and form an excellent image without color misregistration.

According to the image forming apparatus of the third aspect, the belt deviation preventing means for preventing the transfer material conveying belt from meandering,
Since the meandering detection roller is brought into contact with the transfer material transport belt from the outside, the cross section of the transfer material transport belt can be made into a small area and the volume occupied in the apparatus can be reduced.
As a result, there is an effect that the entire device can be made compact.

[Brief description of drawings]

FIG. 1 is a perspective view schematically showing a main part of a first embodiment of the present invention.

FIG. 2 is a schematic diagram of a four-tandem tandem type full-color image forming apparatus according to the first embodiment of the present invention.

FIG. 3 is a schematic plan view of the same main portion.

FIG. 4 is a schematic side view of the same main part.

FIG. 5 is a plan view illustrating a state of a belt deviation prevention mechanism when the belt in the embodiment is offset to the left in the traveling direction.

FIG. 6 is an explanatory diagram similarly seen from the side.

FIG. 7 is a plan view showing a state of a belt deviation preventing mechanism when the belt in the embodiment is offset to the right in the traveling direction.

FIG. 8 is an explanatory diagram similarly seen from the side.

FIG. 9 is a diagram showing a first modification of the belt cleaning device in the embodiment.

FIG. 10 is a diagram showing a second modification of the belt cleaning device in the embodiment.

FIG. 11 is a diagram showing a third modification of the belt cleaning device in the embodiment.

FIG. 12 is a diagram showing a fourth modification of the belt cleaning device in the embodiment.

FIG. 13 is a view showing a fifth modification of the belt cleaning device in the embodiment.

FIG. 14 is a diagram showing a sixth modification of the belt cleaning device in the embodiment.

FIG. 15 is a schematic plan view showing the main parts of the second embodiment of the present invention.

FIG. 16 is a view showing a modified example of the same embodiment.

FIG. 17 is a perspective view schematically showing a main part of a third embodiment of the present invention.

FIG. 18 is an explanatory plan view showing a state of a belt deviation preventing mechanism when there is no deviation in the belt in the embodiment.

FIG. 19 is an explanatory diagram similarly seen from the side.

FIG. 20 is an explanatory plan view showing a state of a belt deviation preventing mechanism when the belt in the embodiment is offset leftward in the traveling direction.

FIG. 21 is an explanatory diagram similarly seen from the side.

FIG. 22 is a plan view showing a state of a belt deviation preventing mechanism when the belt in the embodiment is offset to the right in the traveling direction.

FIG. 23 is an explanatory diagram similarly seen from the side.

[Explanation of symbols]

1Y, 1M, 1C, 1BK ... Solid-state scanning head, 2Y, 2
M, 2C, 2BK ... Photosensitive drum (image bearing member), 3Y,
3M, 3C, 3BK ... Charging device, 4Y, 4M, 4C, 4
BK ... Developing device, 5Y, 5M, 5C, 5BK ... Transfer device (transfer means), 6Y, 6M, 6C, 6BK ... Cleaning device, 7Y, 7M, 7C, 7BK ... Eliminating device, 8 ... Transfer material, 9 ... Pickup Roller, 19 ... Feed roller, 11 ... Registration roller, 12 ... Transfer material conveying belt,
13 ... Fixing device, 14 ... Sending roller, 15 ... Paper discharge tray, 16 ... Driving roller, 17 ... Followed roller, 18 ... Followed roller compression spring, 21 ... Followed roller holding member 2
1, 22 ... Belt cleaning device, 23 ... Paper feeding cassette, 32 ... Meandering regulation roller, 33 ... Belt unit frame elongated hole, 34 ... String member, 35 ... Compression spring, 3
7 ... Meandering regulation roller fixed bearing (first bearing), 38 ... Meandering regulation roller sliding bearing (second bearing), 24 ... Belt unit frame, 40 ... Meandering detection member, 40A ... Taper section, 41A ... Blade-shaped cleaning member, 41B ... Brush-shaped cleaning member, 41C ... Roll brush-shaped cleaning member, 42 ... Cleaner hopper, 43A ... Blade-shaped belt holding member, 43B ... Roller-shaped belt holding member, 100 ... Belt deviation prevention mechanism (belt deviation prevention means), 105 ... Roller support mechanism (roller support means),
106 ... Roller end displacement mechanism (roller end displacement means)
110 ... Belt cleaning device (belt cleaning means), 120 ...
Detection member cleaning device (detection member cleaning means), 130 ... Second
Belt deviation prevention mechanism (belt deviation prevention means), 1
50 ... Image forming means, 200 ... Conveying means.

Claims (3)

[Claims] 1. A plurality of image forming means, which are respectively provided corresponding to a plurality of image carriers that are sequentially arranged and each form an image on each of the image carriers, and for each of the image carriers. Conveying means having a transfer material conveying belt for sequentially conveying the transfer material, and provided corresponding to each of the image carriers, and formed on each of the image carriers with respect to the transfer material conveyed by the conveying means. An image forming apparatus comprising: a plurality of transfer means for respectively transferring different images; and a belt deviation preventing means for preventing deviation of the transfer material conveying belt of the conveying means. The means is a meandering regulating roller around which the transfer material conveying belt of the conveying means is stretched, and one end side of the meandering regulating roller and rotatably supported independently of the meandering regulating roller and the transfer material conveying belt. A meandering detection member having a taper portion in contact with the end edge portion, and the meandering regulation roller so that the shaft end portion provided with the meandering detection member can be displaced in a direction orthogonal to the rotation axis. A roller supporting means for supporting the meandering detection member, and a cord-shaped member connected to the meandering detection member, and when the rotation torque acts on the meandering detection member due to the contact with the transfer material transport belt, the rotational movement is converted into a linear movement. A roller end displacing means for displacing the shaft end of the meandering regulation roller provided with the meandering detection member in a predetermined direction by conversion, and the transfer material transport belt running more than the position where the meandering detection member is disposed. An image forming apparatus, comprising: a belt cleaning unit that is located on the upstream side in the direction and that cleans a region including a contact region of the transfer material transport belt with the meandering detection member. 2. A plurality of image forming means, which are respectively provided corresponding to a plurality of image carriers that are sequentially arranged and each form an image on each of the image carriers, and for each of the image carriers. Conveying means having a transfer material conveying belt for sequentially conveying the transfer material, and provided corresponding to each of the image carriers, and formed on each of the image carriers with respect to the transfer material conveyed by the conveying means. An image forming apparatus comprising: a plurality of transfer means for respectively transferring different images; and a belt deviation preventing means for preventing deviation of the transfer material conveying belt of the conveying means. The means is a meandering regulation roller around which the transfer material conveyance belt of the conveying means is hung, and one end side of the meandering regulation roller and rotatably supported independently of the meandering regulation roller and the transfer material conveyance belt. A meandering detection member having a taper portion in contact with the end edge portion, and the above-mentioned meandering regulation member so that the shaft end portion provided with the meandering detection member can be displaced in a direction orthogonal to the rotation axis. A roller supporting unit that supports a roller and a string-shaped member connected to the meandering detection member are provided, and when the rotation torque acts on the meandering detection member due to contact with the transfer material transport belt, the rotational movement is linearly moved. To a roller end displacing means for displacing the shaft end of the meandering regulation roller provided with the meandering detection member in a predetermined direction, and a contact area of the meandering detection member with the transfer material transport belt is cleaned. An image forming apparatus, comprising: 3. A plurality of image forming means which are provided corresponding to a plurality of image carriers that are sequentially arranged and form images on the respective image carriers, and for each of the image carriers. Conveying means having a transfer material conveying belt for sequentially conveying the transfer material, and provided corresponding to each of the image carriers, and formed on each of the image carriers with respect to the transfer material conveyed by the conveying means. An image forming apparatus comprising: a plurality of transfer means for respectively transferring different images; and a belt deviation preventing means for preventing deviation of the transfer material conveying belt of the conveying means. The means includes a rotatable meandering-regulating roller that comes into contact with the transfer material conveying belt of the conveying means from the outside, and one side of the meandering-regulating roller and rotatably supported independently of the meandering-regulating roller. Turning A meandering detection member having a taper portion in contact with the edge portion of the copying material conveying belt, and a shaft end portion provided with the meandering detection member so as to be displaceable in a direction orthogonal to the rotation axis. A roller supporting unit that supports the meandering regulation roller, and a string-shaped member that is connected to the meandering detection member. When the rotation torque acts on the meandering detection member due to the contact with the transfer material transport belt, the rotation thereof is performed. An image forming apparatus comprising: a roller end displacing unit that displaces a shaft end of a meandering regulation roller provided with a meandering detection member in a predetermined direction by converting the movement into a linear movement. apparatus.