JP6071481B2 - Belt conveying apparatus and image forming apparatus - Google Patents

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a belt conveyance device that rotates and moves an endless belt while being stretched by a plurality of stretching members, and an image forming apparatus such as a printer or a copier that uses an electrophotographic system including the belt conveyance device. It is.

  2. Description of the Related Art Conventionally, some image forming apparatuses such as printers and copiers using an electrophotographic system use a belt conveyance device that rotates and moves an endless belt while being stretched by a plurality of stretching members. In such a belt conveyance device, there is a problem that when the belt is rotationally moved, the belt approaches one end side in the belt width direction (axial direction of the stretching roller) that is a direction orthogonal to the belt movement direction. Are known.

  In order to solve this problem, for example, Patent Document 1 discloses a configuration that regulates the deviation of the belt using a force (rotational torque) in the moving direction of the belt. Specifically, in Patent Document 1, the initial position (initial phase) is determined by the biasing spring, and the contact member that rotates in the moving direction of the belt by contacting the moving belt and the contact member rotate integrally. It has a cam to play. And in patent document 1, when a belt approaches the belt width direction one end side, a belt and a contact member will contact and a rotational torque will be transmitted from a belt to a contact member. When the contact member rotates by a certain angle or more, the cam displaces the position of the driven roller shaft end portion in a direction perpendicular to the axial direction. Accordingly, in Patent Document 1, the driven roller is tilted with respect to the driving roller as a shift adjusting tension member, and the shift of the belt is adjusted.

Japanese Patent Laid-Open No. 11-116089

  However, as in Patent Document 1, when the driven roller is used as a shift adjustment tension member, when the belt is moved to one end side, the driven roller is moved to the other end side of the belt by the reaction force of the shift force. The phenomenon may occur.

  When the driven roller moves to the other end side of the belt by a reaction force, the moving force may hinder the operation for adjusting the deviation of the driven roller.

  Accordingly, an object of the present invention is to regulate the belt deviation while adjusting the deviation of the driven roller itself in the belt width direction when the driven roller as the deviation adjusting tension member is inclined with respect to the other tension members. It is an object of the present invention to provide a belt conveyance device that can be used, and an image forming apparatus including the belt conveyance device.

  In order to solve the above-described problems, the present invention includes an endless belt that rotates and a plurality of stretching members that stretch the belt, and the belt is orthogonal to the moving direction of the belt. In the belt conveyance device that regulates the deviation of the belt by tilting one of the plurality of stretching members with respect to the other stretching member when approaching one end side in the belt width direction. The offset adjusting tension member is an offset adjusting tension roller that is movable in contact with the belt, and is provided on the rotation shaft of the offset adjusting tension roller and is movable and receives a force from the belt. A member, and a bearing portion that includes a restricting portion that restricts the movement of the roller in the width direction, and supports the shaft of the roller, and the adjustment member and the offset adjusting tension roller are in contact with each other by the restricting portion Not to feature That.

  According to the present invention, when the driven roller as the shift adjustment tension member is tilted with respect to the other tension members, the shift of the belt can be adjusted while restricting the shift of the driven roller itself in the belt width direction. It becomes possible.

Schematic of an image forming apparatus provided with a belt conveying device of the present invention 1 is a perspective view of an intermediate transfer belt unit according to Embodiment 1. FIG. FIG. 3 is a perspective view of an end portion side of a tension roller 7 that applies tension to the intermediate transfer belt 5 according to the first exemplary embodiment. FIG. 3 is an exploded perspective view for explaining components of the belt deviation adjusting mechanism of the first embodiment. Sectional view of the belt offset adjusting mechanism as seen from the direction of arrow B in FIG. The partial side view of the belt shift adjustment mechanism of Embodiment 1 The figure explaining operation | movement of the adjustment member of the belt deviation adjustment mechanism of Embodiment 1. The figure explaining the rotation angle of the adjustment member of Embodiment 1, and the displacement amount of a bearing The figure explaining operation | movement of the belt deviation adjustment mechanism of Embodiment 1. The figure explaining the force which acts on the adjustment member which is not connected to the link member The figure explaining the relationship between the rocking | fluctuation shaft of a connection member, and an adjustment member The figure explaining the comparison composition of a belt shift adjustment mechanism The figure explaining the control part of Embodiment 1. The figure explaining the other belt shift adjustment mechanism of Embodiment 1. Sectional drawing of the intermediate transfer belt unit of Embodiment 2 Schematic explaining the shape of the adjustment member of Embodiment 2. Schematic explaining the relationship between the adjustment member of Embodiment 2, a bearing guide part, and a friction surface.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described in the following embodiments should be appropriately changed according to the configuration of the apparatus to which the present invention is applied and various conditions. Therefore, unless specifically stated otherwise, the scope of the present invention is not intended to be limited thereto.

(Embodiment 1)
(Overall configuration of image forming apparatus)
An embodiment of an image forming apparatus provided with a belt conveyance device according to the present invention will be described. FIG. 1 is a sectional view of an intermediate transfer type electrophotographic color image forming apparatus. An intermediate transfer belt unit 16 is provided as a belt conveyance device provided with a belt deviation adjusting mechanism according to the present invention.

(Overall configuration of image forming apparatus)
FIG. 1 is a schematic diagram illustrating an example of a color image forming apparatus. The configuration of the image forming apparatus according to the present embodiment will be described with reference to FIG. The image forming apparatus 10 forms an image on a transfer material P such as a recording sheet or an OHP sheet by an electrophotographic method in accordance with a signal sent from an external device such as a personal computer that is communicably connected to the image forming apparatus 10. can do.

  In the image forming apparatus 10, a plurality of image forming units a, b, c, and d that form toner images of yellow, magenta, cyan, and black are arranged linearly in a substantially horizontal direction here. . Further, a belt conveyance device is disposed so as to face each of the image forming units a, b, c, and d. The belt conveyance device of the present embodiment is a transfer unit in which a belt and other members are unitized.

  The transfer unit of the present embodiment is stretched by stretch members (drive roller 6, tension roller 7, driven roller 8), and an endless belt (intermediate transfer belt) 5 as an intermediate transfer member is attached to each image forming unit a. , B, c, and d, an intermediate transfer belt unit 16 that rotates and moves. Each of the image forming units a, b, c, and d has the same configuration and operation except that the color of the toner image to be formed is different. Therefore, the configuration of the image forming unit a will be described as a representative.

  In the image forming unit a, a toner image is formed by a known electrophotographic image forming process. The image forming unit a is provided with a cylindrical electrophotographic photosensitive member, that is, a photosensitive drum 1a, as an image carrier so as to be rotatable in the direction of an arrow in the figure. In the image forming operation, first, the surface of the rotating photosensitive drum 1a is charged by the charging roller 2a serving as charging means. Next, the laser scanner 3 as an exposure unit emits light in accordance with a signal sent from the computer, and an electrostatic latent image is formed on the photosensitive drum 1a by performing scanning exposure on the charged photosensitive drum 1a. The electrostatic latent image formed on the photosensitive drum 1a is visualized as a toner image when the developing roller 4a as a developing unit supplies toner as a developer. The toner image visualized on the photosensitive drum 1a is statically transferred onto the belt 1 by the action of a primary transfer roller 9a which is a primary transfer unit disposed opposite to the photosensitive drum 1a via the belt 1 in the primary transfer portion T1. It is transferred electronically. The primary transfer residual toner remaining on the surface of the photosensitive drum 1 is cleaned and removed by the cleaning device 11a and then subjected to an image forming process below charging.

  Through the above process, the toner images formed on the photosensitive drums 1a of the image forming units a, b, c, and d with the movement and timing of the belt 1 are sequentially superimposed and transferred onto the belt 1. A color toner image is formed.

  On the other hand, the transfer material P sent out from the transfer material accommodating portion by the feeding means 9a or the like takes a timing to contact the secondary transfer roller 12 as the secondary transfer means and the belt 5 (secondary transfer portion). It is conveyed to T2. Thus, the toner image on the belt 1 is electrostatically transferred to the transfer material P by the action of the secondary transfer roller 12 in the secondary transfer portion T2.

  Next, the transfer material S is separated from the belt 1 and conveyed to the fixing unit 14 where the toner image on the transfer material P is pressurized and heated to be firmly fixed on the transfer material P. Thereafter, the transfer material P is conveyed and discharged onto a discharge tray. Further, the secondary transfer residual toner remaining on the surface of the intermediate transfer belt 5 is cleaned and removed by the transfer belt cleaning means 15.

  The density of the toner image primarily transferred onto the intermediate transfer belt 5 can be detected by a sensor unit 24 provided at a position facing the tension roller 7 via the intermediate transfer belt 5.

  In the image forming apparatus 10 of the present embodiment, the intermediate transfer belt unit 16 that is a transfer unit is also detachable from the image forming apparatus 10. That is, the belt conveying device is configured to be detachable from the image forming apparatus. Further, the photosensitive drums 1a, b, c, and d and the developing rollers 4a, b, c, and d of each image forming unit 110 are integrated into a cartridge by a frame and can be attached to and detached from the image forming apparatus 10. A cartridge may be used.

(Description of schematic configuration of intermediate transfer belt unit)
Next, the configuration of the intermediate transfer belt unit 16 and the belt deviation adjusting mechanism will be described with reference to FIGS. The intermediate transfer belt unit 16 includes an intermediate transfer belt 5, a plurality of stretching members (a driving roller 6, a tension roller 7, and a driven roller 8) that stretch the intermediate transfer belt 5, and a frame member that supports the plurality of stretching members. 17R and L are units. Further, the intermediate transfer belt unit 16 includes primary transfer rollers 9a, b, c, and d. The intermediate transfer belt unit 16 is configured to be positioned with respect to the main body frame member 60 of the image forming apparatus 10.

  FIG. 2 is a perspective view of the intermediate transfer belt unit 16. For explanation of the internal mechanism, the intermediate transfer belt 5 and the sensor unit 24 are not shown.

  As shown in FIG. 2, the driving roller 6 and the driven roller 8 are positioned with respect to the frame members 17L and 17R via bearings. The rotation shafts of the driving roller 6 and the driven roller 8 are supported by a bearing so as to be rotatable. The tension roller 7 is supported by adjustment members 21L and 21R described later so as to be movable with respect to the frame members 17R and 17L. The driving roller 6 is rotationally driven by a driving unit (not shown) and conveys the intermediate transfer belt 5. The tension roller 7 and the driven roller 8 are driven in contact with the intermediate transfer belt 5.

  A configuration for applying tension to the intermediate transfer belt 5 will be described with reference to FIGS. FIG. 3 is a perspective view of the end side of the tension roller 7 that applies tension to the intermediate transfer belt 5. FIG. 4 is an exploded perspective view illustrating components of the belt deviation adjusting mechanism. Further, FIG. 5 is a cross-sectional view of the belt-side adjustment mechanism viewed from the direction of arrow B in FIG.

  As shown in FIG. 3, the tension roller bearing 18L (18R) is slidably engaged with the tension roller bearing holder 19L (19R) in the direction of arrow A. The tension roller bearing 18L (18R) has a tension roller rotating shaft 50 that applies tension to the intermediate transfer belt 5 by an urging means (tension spring 20) provided between the tension roller bearing holder 19L (19R). The tension roller 7 is urged through.

  As shown in FIGS. 4 and 5, the tension roller 7 includes a tension roller sleeve 7a, a tension roller flange 7b, and a tension roller rotating shaft 50, and is configured to rotate integrally. Both ends of the rotary shaft 50 of the tension roller are pivotally supported by tension roller bearings 18L and 18R that are bearing support members.

  Next, a belt shift adjustment mechanism that functions when the belt approaches one end side in the belt width direction orthogonal to the moving direction will be described. The belt shift adjustment mechanism of the present embodiment includes at least a tension roller 7 as a shift adjustment stretch member, a first adjustment member, and adjustment members 21L and 21R as second adjustment members. Here, since the configurations of the adjustment members 21L and 21R are the same, the adjustment member that comes into contact with the belt when the intermediate transfer belt 5 approaches is defined as the first adjustment member as the second adjustment member.

  The adjustment members 21L and 21R are configured to be movable by contacting the belt and receiving a force from the belt. The adjustment members 21L and 21R are provided on both ends of the rotary shaft of the tension roller 7 as shown in FIG. Yes. Specifically, the adjusting members 21L and 21R have a cam shape, and rotate in the same direction as the moving direction of the belt by coming into contact with the belt when the belt approaches the belt width direction. The cam curved surfaces 21b of the adjusting members 21L and 21R are in contact with the rubbing surface 22 formed on the main body frame member 60 (see FIG. 1). The adjustment members 21L and 21R are supported by the tension roller bearings 18L and 18R, and are rotatably engaged with the tension roller bearings 18L and 18R. Therefore, the rotation shafts of the adjustment members 21L and 21R are coaxial with the rotation shaft of the tension roller 7.

  As shown in FIG. 5, the positions of the tension roller bearings 18L and 18R, the tension roller rotating shaft 50, and the tension roller 7 in the Z direction (hereinafter, the Z direction is referred to as the height direction) are the rubbing surface 22 and the adjusting member. 21L and 21R.

  FIG. 6 is a partial side view of the belt side adjusting mechanism on the L side. The relationship between the members on the R side is the same as in FIG. As shown in FIG. 6, the tension roller bearing holder 19L is held so as to be swingable by a predetermined angle about the bearing holder fulcrum 19a with respect to the frame member 17L. That is, the tension roller bearing holder 19L is configured to be able to follow the height of the tension roller 7 defined by the adjustment member 21L while holding the tension spring 20.

  FIG. 7 is a view showing the relationship between the operation of the adjusting member 21L and the operation of the tension roller 7. As described above, the cam curved surface 21b formed on a part of the adjustment member 21L is in contact with the rubbing surface 22 that is a fixed surface. Further, the cam shape is such that the height of the tension roller bearing 18L is continuously changed by the rotational phase of the adjusting member 21L. Specifically, in FIG. 7B, when the adjustment member 21L rotates in the conveyance direction of the intermediate transfer belt 5 (C direction), the tension roller bearing 18L operates to be lowered (state of FIG. 7C). . In FIG. 7B, when the adjustment member 21L rotates in the direction opposite to the belt moving direction (−C direction), the tension roller bearing 18L operates to be lifted (state shown in FIG. 7A).

  FIG. 8 is a diagram for explaining the rotation angle of the adjusting member and the amount of displacement of the bearing. The relationship between the rotation angles of the adjusting members 21L and 21R and the displacement amounts of the tension roller bearings 18L and 18R is approximately as shown in FIG. The tension roller rotating shaft 50 and the tension roller 7 supported by the tension roller bearings 18L and 18R also follow the tension roller bearings 18L and 18R and are displaced.

  When one of the adjusting members 21L and 21R moves in the rotation direction of the intermediate transfer belt 5 when the intermediate transfer belt 5 is moved in the belt width direction, the other moves in conjunction with the opposite direction.

  In the present embodiment, the adjusting members 21L and 21R are connected by a connecting member (link member 23) provided as interlocking means, as shown in FIG. The link member fulcrum shaft 23a of the link member 23 is swingably supported by the frame member 17C in a substantially central region in the width direction of the intermediate transfer belt 5. The link member 23 includes adjustment member engagement portions 23b-L and 23b-R. The adjustment member engagement portions 23b-L and 23b-R are respectively connected to the link member engagement portions 21d of the adjustment members 21L and 21R. Is engaged. The link member engaging portions 21d of the adjustment members 21L and 21R are provided on the upstream side of the rotation shaft of the tension roller. When one of the adjusting members 21L and 21R is rotated in a certain direction (C direction) by the connecting member, the other is configured to rotate approximately the same angle in the reverse direction (−C direction) via the link member 23. .

(Outline explanation of belt-side adjustment operation)
FIG. 9 is a diagram for explaining the operation of the belt deviation adjusting mechanism. The misalignment adjustment operation of the belt conveyance device of the present embodiment will be described with reference to FIGS.

  As shown in FIG. 9A, the intermediate transfer belt 5 is conveyed in the K direction by the drive roller 6. Here, the adjustment operation when the intermediate transfer belt 5 is moved in the F direction will be described.

  When the intermediate transfer belt 5 moves in the direction of arrow F, the belt end 5a comes into contact with the belt rubbing surface 21c of the adjusting member 21R, and the shift of the intermediate transfer belt 5 in the F direction is adjusted (FIG. 5B). )). By adjusting the deviation of the belt, a contact pressure is generated between the belt end 5a and the belt rubbing surface 21c. This contact pressure is called an offset force. If the belt deviation adjusting mechanism is not provided, if this deviation force increases, the load on the belt end increases, which may lead to damage to the intermediate transfer belt 5.

  When the belt end 5a comes into contact with the belt rubbing surface 21c of the adjustment member 21R, the belt end 5a causes the belt end 5a to move the adjustment member 21R as shown in FIG. The intermediate transfer belt 5 is rotated in the direction of rotation (arrow C direction). With the rotation of the adjusting member 21R in the C direction, the end of the tension roller 7 on the side (R side) where the intermediate transfer belt 5 is moved down. At the same time, the adjustment member 21R swings the linked link member 23 about the link member fulcrum 23a, and the link member 23 moves the adjustment member 21L on the other end side in the direction opposite to the belt moving direction (−C direction). ) To rotate. Along with the rotation of the adjusting member 21L, the end of the tension roller 7 on the opposite side (L side) to the side where the intermediate transfer belt 5 is offset moves upward.

  With the above operation, the tension roller 7 is inclined with respect to the drive roller 5. Both end portions of the tension roller 7 are displaced by approximately the same amount in the opposite directions by the link member 23, that is, the tension roller 7 is inclined symmetrically with respect to the link member fulcrum 23a in the belt width direction.

  The belt conveyance device of the present embodiment tries to move the intermediate transfer belt 7 in the direction opposite to the initial shift direction (F direction) by the inclination of the tension roller 7, so that the shift of the intermediate transfer belt 7 is adjusted, Reduce the shifting force. When the shifting force of the intermediate transfer belt 5 becomes sufficiently small, the belt end 5a loses the force for rotating the adjusting member 21R, and the adjusting member 21R stops rotating. At the same time as the adjusting member 21R stops rotating, the adjusting member 21L also stops rotating. The adjustment member 21R and the adjustment member 21L maintain their positions (phases) after stopping the rotation.

  As described above, the belt shift adjustment mechanism of the present embodiment is configured such that when the belt shift occurs, the adjustment members 21L and 21R move in the opposite directions to tilt the tension roller 7, This is a configuration that is easier to tilt than a configuration that tilts only with one adjusting member.

  FIG. 10 shows the force acting on the adjusting member 21 </ b> R that is not connected to the link member 23. A point I is a contact point between the adjusting member 21R and the rubbing surface 22, and Lw indicates a distance between the shafts 21a and I in the horizontal direction. Here, the shaft 21a is the rotation center of the adjustment member 21R.

  The adjusting member 21R is in contact with the rubbing surface 22 at the point I, and the weight W (R) of the tension roller 7 acts on the position of the shaft 21a shifted by Lw. Therefore, a force rotating in the J direction acts on the adjustment member 21R. The same applies to the adjustment member 21L on the opposite side. That is, the adjustment members 21R and 21L rotate in the J direction with each other in a freely rotatable state, and the tension roller bearings 18R and 18L rotate together as shown in FIG. Therefore, in order to rotate the position of the tension roller bearings 18R and 18L in the direction opposite to the J direction, a biasing force of a biasing member such as a spring that pulls the tension roller bearings 18R and 18L is required.

  However, in this embodiment, it is not necessary to provide a biasing means such as a tension spring. As shown in FIG. 11, adjustment members 21L and 21R are provided at substantially symmetrical positions around the swing shaft 23a. The weights of the tension roller 7 are applied to the adjusting members 21L and 21R substantially evenly, and the rotational moments thereof are also substantially uniform. This indicates that the rotational moment applied to the adjustment members 21L and 21R on both sides is balanced via the link member 23 in a state where no offset force is generated in the intermediate transfer belt 5, and the stationary state can be maintained. That is, in the present embodiment, the inclination of the tension roller 7 can be maintained independently without depending on the force received from the intermediate transfer belt 7 or the force of the urging means such as a tension spring.

  Further, the link member 23 allows the rotation amount of one adjustment member and the reverse rotation amount of the other adjustment member to be substantially equal, and the rotation moments of the adjustment members 21L and 21R can be kept balanced. It is.

  Further, in the present embodiment, since it is not necessary to rotate the adjustment members 21L and 21R against the urging force of the urging member, the adjustment members 21L and 21R can be rotated with a small load.

(Detailed explanation regarding the position restriction of the tension roller in the belt width direction)
Next, a tension roller position regulating method in the belt width direction will be described. When a shifting force in the belt width direction is generated on the intermediate transfer belt 7, the tension roller 7 receives a reaction force of the belt shifting force and may move in the opposite direction of the intermediate transfer belt 7. FIG. 12 is a diagram for explaining a belt shift adjustment mechanism in which the tension roller flange 7b of the tension roller 7 can directly contact the adjustment members 21L and 21R.

  As described above, the tension roller 7 includes the tension roller sleeve 7a, the tension roller flange 7b, and the tension roller rotating shaft 50, and is configured to rotate integrally. Both ends of the rotary shaft 50 of the tension roller are pivotally supported by tension roller bearings 18L and 18R that are bearing support members. In FIG. 12, when the intermediate transfer belt moves toward the F direction, the adjusting member 21R receives the moving force of the belt and tries to move in the same direction as the moving direction of the belt. At this time, when the tension roller 7 moves in the −F direction due to the reaction force of the belt shifting force, the adjustment member 21L on the opposite side of the tension roller flange 7b comes into contact. In the shift adjusting mechanism of the present embodiment, when the adjusting member 21R rotates in the belt moving direction, the adjusting member 21L tries to rotate in the direction opposite to the belt moving direction by the link member 23. At that time, the adjustment member 21L receives a force in the belt moving direction from the tension roller flange 7b in contact with the adjustment member 21L, which hinders the operation of the adjustment member 21L by the link member 23, and the shift adjustment mechanism may not operate correctly. . Even if the link member 23 is not provided, if the tension roller 7 moves in the belt width direction, the shift adjustment mechanism may not operate correctly. This is because, when the adjustment member 21R rotates in the belt moving direction and the shift adjustment is performed by lowering the R side of the tension roller 7 downward from the L side, the adjustment roller 21L also rotates in the belt moving direction. This is because the L side also falls downward, making it difficult to produce a desired inclination.

  Therefore, in this embodiment, the tension roller flange 7b of the tension roller 7 is configured not to contact the adjusting members 21L and 21R.

  FIG. 13A is an explanatory view showing a state in which the intermediate transfer belt 5 is shifted in the F direction, and FIG. 13B is an enlarged view of the L side in FIG. 13A.

  The tension roller bearing 18L includes a restriction portion 18L-z that comes into contact with the tension roller flange 7b. By this restricting portion 18L-z, the tension roller flange 7b cannot move further in the -F direction, and the contact between the adjustment member 21L and the tension roller flange 7b can be prevented. As a result, when the belt approaches the F direction, the adjusting member 21L rotates in the direction opposite to the belt moving direction by the link member 23 without receiving a rotating force in the belt moving direction.

  Further, as shown in FIG. 14, the tension roller 7 may be configured such that the tension roller 7 and the tension tension shaft 50 are integrally formed so as to be rotatable with respect to the tension roller bearings 18L and 18R. In this case as well, the position of the tension roller 7 in the width direction can be restricted by the tension roller bearings 18L and 18R. For example, as shown in FIG. 14, when the tension roller 7 tries to move in the −F direction when the belt moves in the F direction, the tension roller 7 is positioned in the belt width direction by the restricting portion 18 </ b> L-z of the tension roller bearing 18 </ b> L. Can be regulated.

  Therefore, it is possible to adjust the deviation of the belt while regulating the movement of the deviation adjusting tension roller in the belt width direction by the belt deviation adjusting mechanism of the present embodiment.

(Embodiment 2)
In the first embodiment, the configuration has been described in which the tension roller 7 that applies tension to the intermediate transfer belt 5 with the spring 20 is adjusted by tilting the tension roller 7 with the adjustment members 21L and 21R. On the other hand, in the present embodiment, a description will be given of a configuration in which the belt deviation is adjusted by inclining the driven roller 8 driven and rotated by the belt 5 by the adjusting members 21L and 21R. Since other configurations are the same as those of the image forming apparatus according to the first embodiment, the same portions are denoted by the same reference numerals and described.

  As shown in FIG. 15, the present invention can also be applied to a configuration in which adjustment members 21L and 21R are provided at both ends of the driven roller 8. First, the operation of the shift adjustment mechanism will be described. Similarly to the first embodiment, when the belt 5 approaches one end side and contacts the adjustment member 21L, the adjustment member 21L rotates by receiving a rotational force from the belt 5.

  The cam curved surface 21b is also rotated by the rotation of the adjusting member 21L, the contact state between the cam curved surface 21b and the rubbing surface 22 is changed, and the end of the driven roller 8 is displaced in the −X direction. When the adjusting member 21L rotates, the adjusting member 21R connected by the link member 23 rotates in the reverse direction, and the end of the driven roller 8 supported by the adjusting member 21R is displaced in the + X direction. In this way, the displacement of the belt 5 can be adjusted by displacing the driven roller 8 in the X direction so as to return the displacement of the belt 5.

  Next, a detailed configuration of the shift adjustment mechanism will be described. Since the configuration of each member is the same on the L side and the R side, L and R will be described below without distinction. FIG. 16 is a schematic diagram illustrating the shapes of the adjusting members 21L and 21R of the present embodiment. FIG. 17 is a schematic diagram illustrating the relationship among the adjustment member 21, the bearing guide portion 17, and the rubbing surface 22 according to the present embodiment.

  In the present embodiment, both ends of the driven roller 8 are supported by the adjustment member 21 and the driven roller bearing 41. By fitting the cam curved surface 21 b to the rubbing surface 22, the adjustment member 21 is configured to restrict the position of the end portion of the driven roller 8 in the X direction. That is, the adjustment member 21 uniquely determines the position of the end portion of the driven roller 8 in the X direction.

  Here, the adjustment member 21 does not regulate the position of the end portion of the driven roller 8 in the Z direction. The adjusting member 21 supports both ends of the driven roller 8, and each adjusting member 21 is coupled by a link member 23 as in the first embodiment.

  The driven roller bearing 41 is configured to come into contact with the bearing guide portion 17b by the tension of the belt 5 and regulate the position of the end portion of the driven roller 8 in the Z direction. The driven roller bearing 41 supports both ends of the driven roller 8, and the driven roller bearing 41 can move separately in the X direction. That is, the adjusting member 21 and the driven roller bearing 41 position each of the driven roller at both ends. Further, the driven roller bearing 41 is constituted by a rotatable cylindrical bearing, and the sliding resistance between the driven roller bearing 41 and the bearing guide portion 17b is reduced. Therefore, the driven roller bearing 41 can move smoothly in the X direction.

  In the present embodiment, the adjustment member 21 and the driven roller bearing 41 are configured as separate parts, and the tension of the belt 5 is supported by the driven roller bearing 41. That is, the tension of the belt 5 is configured not to act on the contact portion between the cam curved surface 21 b and the rubbing surface 22. Therefore, the tension of the belt 5 does not become the rotational load of the adjustment member 21, and the rotational load of the adjustment member 21 can be kept small.

  Here, in this embodiment, the cam curved surface 21b is made of polyacetal having high slidability, and the sliding resistance with the rubbing surface 22 is reduced. Therefore, the adjusting member 21 can rotate even if the rotational force received from the belt 5 is small. In the present embodiment, the cam rubbing surface 21b has a small radius. Therefore, the brake moment that suppresses the rotation of the adjusting member 21 can be reduced. That is, the rotational load on the adjustment member 21 can be reduced, and the adjustment member 21 can be rotated even if the rotational force received from the belt 5 is small.

  Also in Embodiment 2, it is possible to prevent the end portions of the driven roller 8 from coming into direct contact with the adjusting members 21L and 21R by providing the adjusting members 21L and 21R and the regulating portion on the driven roller bearing portion 41. .

  Therefore, it is possible to adjust the deviation of the belt while regulating the movement of the deviation adjusting tension roller in the belt width direction by the belt deviation adjusting mechanism of the present embodiment.

5 Intermediate Transfer Belt 7 Tension Roller 16 Intermediate Transfer Belt Unit 18 Tension Roller Bearing 18L-z Restricting Portion 19 Tension Roller Bearing Holder 21 Adjustment Member 22 Cam Slide Surface 23 Link Member

Claims (11)

An endless belt that rotates and a plurality of stretching members that stretch the belt, and when the belt approaches one end side in a belt width direction orthogonal to the moving direction of the belt, In the belt conveyance device that adjusts the deviation of the belt by tilting one of the tension members of the tension member to the other tension member,
The offset adjusting tension member is an offset adjusting tension roller that is movable in contact with the belt,
A bearing that is provided on a rotation shaft of the offset adjusting tension roller and is movable by receiving a force from the belt, and a bearing that supports the shaft of the roller, including a regulating portion that regulates the movement of the roller in the width direction. A belt conveying device, wherein the adjusting member and the offset adjusting tension roller are not in contact with each other by the restricting portion. As the adjustment member, a first adjustment member and a second adjustment member are provided at both ends of the shift adjustment tension roller in the belt width direction,
Interlocking means for interlocking movement of the first adjustment member and movement of the second adjustment member;
When the belt is close to the one end side, the first adjustment member is moved by receiving a force from the belt, and the second adjustment member is moved by the interlocking means, whereby the shift adjustment tension roller The belt conveying device according to claim 1, wherein the belt is inclined with respect to another tension member.   When the belt approaches the other end side in the belt width direction, the second adjusting member receives a force from the belt and moves, and the first adjusting member moves by the interlocking means, The belt conveying device according to claim 2, wherein the shift adjusting tension roller is inclined with respect to another tension member. When the belt approaches the one end side,
The first adjusting member can be rotated in the same direction as the moving direction of the belt by receiving a force from the belt, and the second adjusting member can be rotated in the direction opposite to the moving direction of the belt by the interlocking means. The belt conveying device according to claim 2 or 3, wherein the belt conveying device is possible. The interlocking means connects a part of the first adjustment member and a part of the second adjustment member, and swings about a swing shaft provided in a substantially central region in the belt width direction. The belt conveyance device according to any one of claims 2 to 4 , wherein the belt conveyance device is a possible connecting member.   The first and second adjusting members have a cam shape and are rotatable with respect to the offset adjusting tension roller about a rotation axis of the offset adjusting tension roller. The belt conveyance apparatus as described in any one of Claims 5.   7. The belt according to claim 2, wherein the belt can contact the first adjusting member at a belt end portion on the one end side in the belt width direction when approaching the one end side. The belt conveyance apparatus as described in any one.   Each of the first and second adjusting members includes an engaging portion that engages with the interlocking means on the inner peripheral side of the belt with respect to the rotation shaft of the shift adjusting tension roller in the moving direction of the belt. The belt conveying device according to claim 6. The offset adjusting tension member is a tension roller that applies tension to the belt to be biased by a biasing means;
A bearing support member that holds the shaft of the tension roller and the first or second adjustment member,
The belt conveying device according to any one of claims 2 to 8, wherein the bearing support member is rotatable about a fulcrum. In the belt width direction, the restricting portion provided on the other end side contacts the shift adjusting tension roller that receives a force from the belt so as to move to the other end side, and The belt conveying device according to any one of claims 1 to 9, wherein movement is restricted. A belt conveying device and a plurality of image carriers each carrying a toner image of a different color; transferring the toner images from the plurality of image carriers to the belt; and transferring the toner images from the belt to a transfer material An image forming apparatus that
An image forming apparatus comprising the belt conveyance device according to any one of claims 1 to 10 as a belt conveyance device including the belt.

Images