JP2015184301A - Belt conveyance device and image forming apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a belt conveyance device configured to ensure high-response control with respect to variability of skew of an endless belt.SOLUTION: When an intermediate transfer belt 13 skews toward a cam 86 in a belt width direction of the intermediate transfer belt 13, a stretch roller 16 is inclined by the cam 86. When the intermediate transfer belt 13 skews apart from the cam 86, the stretch roller 16 is inclined in a direction opposite the above inclination direction by an action of frictional force between a cleaning blade 96 and the intermediate transfer belt 13.

Description

  The present invention relates to a belt conveyance device that stretches an endless belt, and an image forming apparatus such as a copying machine or a laser beam printer (LBP) equipped with the belt conveyance device.

  Many image forming apparatuses are equipped with a belt conveyance device using an endless belt represented by an intermediate transfer belt or a sheet conveyance belt. Conventionally, the endless belt is stretched by a plurality of rollers including a driving roller. And it is conveyed according to rotation of this drive roller by the friction of the outer peripheral surface of a drive roller, and the inner peripheral surface of an endless belt. At that time, meandering occurs in the width direction of the endless belt due to an error in the left and right circumferential length in a direction orthogonal to the conveying direction of the endless belt (hereinafter referred to as “width direction”), unevenness in the left and right tension, and the like.

  For example, when meandering occurs in an intermediate transfer belt of a color image forming apparatus that forms a color image by superimposing a plurality of toners, the plurality of toners do not overlap at the same position on the intermediate transfer belt, and color misregistration occurs.

  In particular, along with the recent increase in image quality of image forming apparatuses, interest in color misregistration in the market is high, and scenes where accepted images have not been accepted have increased. Therefore, a belt conveying device that minimizes color misregistration is desired.

  For example, Patent Document 1 describes that a tension roller that stretches an intermediate transfer belt is configured to be swingable in a direction different from the stretching direction, and the meandering of the intermediate transfer belt is corrected. In Patent Document 1, the meandering amount of the intermediate transfer belt is detected, and the control mechanism inclines the stretching roller based on the detection result. The inclination amount of the stretching roller is controlled by re-detecting at a predetermined timing.

JP 2011-118326 A

  However, the left and right circumferential length of the endless belt and the error in tension are inherent. For this reason, the meandering speed of the endless belt and the appropriate inclination amount of the stretching roller cannot be determined uniquely, and feedback is always required. Therefore, even if the meandering of the endless belt is detected as in Patent Document 1, there is a problem that it takes time to stop the meandering.

  The present invention solves the above-mentioned problems, and an object of the present invention is to provide a belt conveyance device capable of highly responsive control with respect to meandering fluctuations of an endless belt.

  In order to achieve the above object, a typical configuration of a belt conveying device according to the present invention includes: an endless belt that rotates, a driving rotating body that stretches the endless belt and rotates the endless belt, and the endless belt A tension rotator that stretches the belt, a rubbing member that contacts and rubs against an outer peripheral surface of the endless belt, and the endless belt when the endless belt approaches a belt width direction perpendicular to the moving direction of the endless belt. A cam member for inclining the tension rotating body using the force of a belt, and when the endless belt approaches the cam member side in the belt width direction, the tension rotation is performed by the cam member. When the body is tilted and the endless belt approaches the side away from the cam member, the tension rotating body is tilted in the direction opposite to the tilting direction by the action of the frictional force between the rubbing member and the endless belt. Let The features.

  According to the above configuration, when meandering occurs in the endless belt, it is possible to stop the meandering of the endless belt by inclining the tension rotating body by the cam member.

1 is an explanatory cross-sectional view illustrating a configuration of an image forming apparatus including a belt conveyance device according to the present invention. It is a schematic explanatory drawing which shows the structure of the belt conveying apparatus which concerns on this invention. It is a perspective explanatory view showing the composition which looked at the belt conveyance device concerning the present invention from the fixed side of a tension rotating body. It is a perspective explanatory view showing the structure of the cleaning means as seen from the fixed side of the tension rotator. It is a perspective explanatory view showing the composition which looked at the belt conveyance device concerning the present invention from the control side of a tension rotating body. It is a disassembled perspective view which shows the structure of a belt meandering control apparatus. It is side surface explanatory drawing which shows the structure which looked at the belt meandering control apparatus from the control side of the stretching rotary body. (A) is partial explanatory drawing which shows the attitude | position of the tension | tensile_strength rotary body before controlling the meandering of an endless belt. (B) is a partial cross-sectional explanatory view showing a posture in which the tension rotator is inclined when the meandering of the endless belt is controlled. (A) is side explanatory drawing seen from the control side of the tension | tensile_strength rotary body which shows the attitude | position of the cleaning means before controlling the meandering of an endless belt. (B) is side explanatory drawing seen from the control side of the tension | tensile_strength rotary body which shows the attitude | position which the cleaning means inclined when controlling meandering of an endless belt. It is side surface explanatory drawing seen from the control side of the tension | tensile_strength rotary body which shows a mode that a cleaning means contact | abuts to the outer peripheral surface of an endless belt. FIG. 4 is a cross-sectional explanatory view showing a configuration of the tension rotator, the endless belt, and the cleaning unit viewed from the control side of the tension rotator when the endless belt is stopped. FIG. 6 is a cross-sectional explanatory view showing a configuration of the tension rotator, the endless belt, and the cleaning unit viewed from the control side of the tension rotator when the endless belt is rotating.

  An embodiment of an image forming apparatus provided with a belt conveyance device according to the present invention will be specifically described with reference to the drawings.

<Image forming apparatus>
FIG. 1 is a cross-sectional explanatory view showing a configuration of an image forming apparatus 1 provided with a belt conveying device 80 according to the present invention. In FIG. 1, photosensitive drums 10y, 10m, 10c, and 10k serving as image carriers are rotatably provided at the center of the image forming apparatus 1. For convenience of explanation, the photosensitive drums 10y, 10m, 10c, and 10k may be simply referred to as the photosensitive drums 10 in some cases. The same applies to other image forming process means.

  Around the photosensitive drum 10, developing rollers 11y, 11m, 11c, and 11k serving as developer carrying members that are rotatable while holding toners of yellow, magenta, cyan, and black k are disposed. .

  The image forming apparatus 1 receives a print signal. Then, the light emitting units 2y, 2m, 2c, and 2k provided on the optical unit 5 serving as the image exposure unit on the surface of the photosensitive drum 10 uniformly charged by the charging roller serving as the charging unit (not shown) correspond to the image information. Laser light 2a is irradiated. As a result, an electrostatic latent image is formed on the surface of the photosensitive drum 10 by charges corresponding to the image information.

  The toner held while the developing roller 11 rotates is supplied to the electrostatic latent image formed on the surface of the rotating photosensitive drum 10. As a result, a toner image is formed on the surface of the photosensitive drum 10.

  An intermediate transfer belt 13 that is an endless belt is stretched opposite to each photosensitive drum 10, and a driving roller 14 that is a driving rotating body that rotates the intermediate transfer belt 13 is provided. Further, an intermediate transfer belt 13 is provided that is an endless belt that is stretched so as to be rotatable and movable by a tension roller 16 that is a tension rotating body that stretches the intermediate transfer belt 13.

  An example of the endless belt according to this embodiment is an example of an intermediate transfer belt 13 that is a transfer belt for transferring a toner image from a photosensitive drum 10 serving as an image carrier to a sheet P serving as a recording material.

  The drive roller 14 is rotationally driven by a motor serving as a drive source via a drive transmission means (not shown). The intermediate transfer belt 13 is driven to rotate in the direction of arrow A in FIG. The tension roller 16 stretches the intermediate transfer belt 13 together with the driving roller 14 with a predetermined tension.

  Primary transfer rollers 12y, 12m, 12c, and 12k serving as primary transfer means are disposed at positions facing the photosensitive drum 10 with the intermediate transfer belt 13 interposed therebetween. The toner image formed on the surface of the photosensitive drum 10 is primarily transferred onto the outer peripheral surface of the intermediate transfer belt 13 by the primary transfer bias voltage applied to the primary transfer roller 12.

  A secondary transfer roller 15 serving as a secondary transfer unit is disposed at a position facing the driving roller 14 with the intermediate transfer belt 13 interposed therebetween. The toner image primarily transferred from the surface of the photosensitive drum 10 onto the outer peripheral surface of the intermediate transfer belt 13 is conveyed to the secondary transfer nip portion 3 opposed to the secondary transfer roller 15 by the rotation of the driving roller 14.

  On the other hand, sheets P serving as recording materials stored in the sheet storage unit 30 are separated and fed one by one in cooperation with a pickup roller 31 serving as a feeding unit and a separation pad 32 serving as a separating unit. Is conveyed in the direction of arrow B. Thereafter, after the skew of the sheet P is corrected by the registration roller 40, the registration roller 40 is synchronized with the timing at which the toner image formed on the outer peripheral surface of the intermediate transfer belt 13 is conveyed to the secondary transfer nip portion 3. Thus, the sheet P is conveyed to the secondary transfer nip portion 3.

  The registration roller 40 conveys the sheet P to the secondary transfer nip portion 3 so that the position of the toner image on the outer peripheral surface of the intermediate transfer belt 13 and the leading edge of the sheet P are aligned. The toner image on the outer peripheral surface of the intermediate transfer belt 13 conveyed to the secondary transfer nip portion 3 has a secondary transfer bias voltage applied to the secondary transfer roller 15 and the secondary transfer roller 15 on the drive roller 14 side. Secondary transfer is performed on the sheet P by the pressure contacted.

  The sheet P on which the toner image is secondarily transferred is sandwiched between the intermediate transfer belt 13 and the secondary transfer roller 15 and conveyed to a fixing unit 50 serving as a fixing unit. In the fixing unit 50, the toner image is fixed on the sheet P by heat from the heating roller 51 and pressure by the pressure roller 52 facing the heating roller 51. The sheet P on which the toner image is fixed is conveyed by a discharge roller 60 and discharged to a discharge unit 70 provided outside the image forming apparatus 1.

<Belt conveyor>
FIG. 2 is a schematic explanatory view showing the configuration of the belt conveying device 80. As shown in FIG. 2, a part of the toner image secondarily transferred onto the sheet P from the outer peripheral surface of the intermediate transfer belt 13 in the secondary transfer nip portion 3 becomes residual toner 6 as the outer peripheral surface of the intermediate transfer belt 13. Remains on top.

  A cleaning member 96 is disposed that is a rubbing member that contacts the outer peripheral surface of the intermediate transfer belt 13 and rubs against the tension roller 16 and collects the residual toner 6 on the outer peripheral surface of the intermediate transfer belt 13. ing. The residual toner 6 remaining on the outer peripheral surface of the intermediate transfer belt 13 is scraped and removed by the cleaning blade 96 and then collected by the cleaner 17 constituting the cleaning means.

  As shown in FIG. 4, a discharge port 98 a for discharging the residual toner 6 scraped and collected by the cleaning blade 96 is provided on the fixed side Q of the stretching roller 16 of the cleaner 17. A discharge port 98a provided on the fixed side Q of the cleaning box 98 is connected to a toner discharge path (not shown) provided in the main body of the image forming apparatus 1 (main body of the image forming apparatus).

  The residual toner 6 collected by the cleaner 17 is conveyed and stored in a collection toner container (not shown) provided in the main body of the image forming apparatus 1. In order to convey the residual toner 6 to the collected toner container, one end portion of the stretching roller 16 disposed on the fixed side Q shown in FIG. 3 is in the stretching direction of the intermediate transfer belt 13 (in the direction of arrow T in FIG. 3). ) Only movable.

  Further, the other end in the longitudinal direction of the stretching roller 16 disposed on the control side R shown in FIG. 5 crosses the stretching direction of the intermediate transfer belt 13 (in the direction of arrow T in FIG. 5) and the stretching direction. It is set as the structure which can move to the up-down direction of FIG.

  Hereinafter, for convenience of explanation, one end side of the stretching roller 16 that can move only in the stretching direction of the intermediate transfer belt 13 (the direction of arrow T in FIG. 3) is referred to as a fixed side Q. Further, the other end side of the stretching roller 16 that is movable in both the stretching direction of the intermediate transfer belt 13 (the direction of arrow T in FIG. 5) and the direction intersecting the stretching direction (the vertical direction in FIG. 5). Is the control side R.

  The discharge path of the residual toner 6 indicated by the arrow G direction in FIG. 4 is provided on the fixed side Q of the tension roller 16 that can move only in the tension direction of the intermediate transfer belt 13.

  FIG. 3 is a perspective explanatory view showing the configuration of the belt conveying device 80 as seen from the fixed side Q of the stretching roller 16. For convenience of explanation, the configuration on the side of the driving roller 14 that stretches the intermediate transfer belt 13 is omitted. The slide member 82 shown in FIG. 3 has an elongated hole 82a formed along the longitudinal direction of the slide member 82 (the direction of arrow T in FIG. 3). Then, bosses 80a and 80b provided in the elongated hole 82a so as to protrude from the main body frame 80e of the belt conveying device 80 in the direction of the rotating shaft 16a of the tension roller 16 are slidably fitted along the elongated hole 82a. Match. As a result, the slide member 82 can slide only in the direction in which the intermediate transfer belt 13 is stretched (the direction of arrow T in FIG. 3).

  Further, the slide member 82 fixedly supports a bearing 83 provided at the end of the rotating shaft 16a of the stretching roller 16. The other end of the tension spring 81 serving as an urging means whose one end is locked to the main body frame 80 e of the belt conveying device 80 is locked to one end of the slide member 82.

  The slide member 82 is always urged to the right in FIG. 3 with respect to the main body frame 80e of the belt conveying device 80 by the extension force of the tension spring 81. Accordingly, the tension roller 16 constantly urges the intermediate transfer belt 13 to the right side (stretching direction) in FIG. 3 via the rotation shaft 16a rotatably supported by the bearing 83 fixed to the slide member 82.

  As shown in FIG. 3, the gear 84 fixed to the rotating shaft 16 a of the stretching roller 16 is provided in the drive unit of the cleaner 17 that collects the residual toner 6 remaining on the outer peripheral surface of the intermediate transfer belt 13. The drive portion of the cleaner 17 is driven by meshing with the drive gear that does not. Accordingly, the residual toner 6 scraped and collected by the cleaning blade 96 can be discharged from the discharge port 98a shown in FIG.

<Cleaning means>
FIG. 4 is a perspective explanatory view showing a configuration viewed from the fixed side Q of the stretching roller 16 of the cleaner 17 serving as a cleaning means. Both end portions of the rotary shaft 16a of the stretching roller 16 are inserted into through holes 98b provided in the cleaning box 98. As a result, the cleaning box 98 is rotatably supported with respect to the rotation shaft 16a of the stretching roller 16.

  The discharge port 98a for discharging the residual toner 6 in the cleaning box 98 is fitted with a positioning member (not shown) provided in the main body frame 80e, whereby the posture of the cleaning box 98 is maintained.

  As shown in FIG. 4, a cleaning blade 96 that collects residual toner 6 on the outer peripheral surface of the intermediate transfer belt 13 is integrally fixed to a pressure member 97 shown in FIG. Yes. As shown in FIG. 10, the pressure member 97 is rotatably supported with respect to the cleaning box 98 with the rotation shaft 100 as the rotation center. As a result, as shown in FIG. 4, the rotation shaft 16a of the tension roller 16 and the rotation shaft 100 of the pressure member 97 to which the cleaning blade 96 is fixed are configured to maintain a constant separation distance.

  As shown in FIG. 4, a box cover 99 is attached to the upper part of the cleaning box 98. As a result, leakage of the residual toner 6 collected in the cleaning box 98 can be prevented.

  The gear 84 shown in FIG. 3 conveys the residual toner 6 collected in the cleaning box 98 in the direction of arrow G in FIG. The conveyed residual toner 6 is accommodated in a collection toner container (not shown) provided in the main body of the image forming apparatus 1.

  FIG. 5 is a perspective explanatory view showing the configuration of the belt conveying device 80 as viewed from the control side R of the stretching roller 16. As shown in FIG. 5, the slide member 87 has a long hole 87 a formed along the longitudinal direction of the slide member 87 (the direction of arrow T in FIG. 5). The bosses 80c and 80d provided in the elongated hole 87a so as to protrude from the main body frame 80e of the belt conveying device 80 in the direction of the rotating shaft 16a are slidably fitted along the elongated hole 87a. doing. As a result, the slide member 87 on the control side R of the tension roller 16 shown in FIG. 5 can be slid only in the tension direction of the intermediate transfer belt 13 (the direction of arrow T in FIG. 5).

  Further, as shown in FIG. 6, a cam base 92, a flange 91, a cam 86, and a bearing 85 are sequentially inserted through the rotating shaft 16 a of the stretching roller 16. The flange 91 is rotatably provided on one end side of the tension roller 16 serving as a tension rotating body on the rotation shaft 16a, and rotates in contact with the rib 90 protruding from the inner peripheral surface of the intermediate transfer belt 13.

  The cam 86 is configured as a cam member that inclines the stretching roller 16 when meandering occurs in the intermediate transfer belt 13. A cam 86 serving as a cam member is a stretched rotating body that utilizes the force of the intermediate transfer belt 13 when the intermediate transfer belt 13 serving as an endless belt approaches a belt width direction orthogonal to the moving direction of the intermediate transfer belt 13. The tension roller 16 is tilted.

  As shown in FIG. 8, the flange 91 has a hat shape in cross section, and a rib 90 provided on the outer peripheral surface of the flange 91 b of the flange 91 so as to protrude from the inner peripheral surface of the intermediate transfer belt 13 contacts and slides. Are arranged to be. The flange 91 is rotatably provided at one end of the rotating shaft 16 a of the stretching roller 16, and comes into contact with a rib 90 provided protruding from the inner peripheral surface of the intermediate transfer belt 13 so as to be integrated with the intermediate transfer belt 13. The tension roller 16 rotates around the rotation shaft 16a.

  The cylindrical portion 86b of the cam 86 is slidably inserted into the through hole 91a of the flange 91, and a convex portion 92a protruding from the cam base 92 is inserted into a slit 86a provided at the end of the cylindrical portion 86b of the cam 86. Is engaged and locked. As shown in FIGS. 5 and 7, the bearing 85 and the cam 86 are supported by a cam control member 88 provided on the slide member 87.

  The cam control member 88 is provided with a through hole 88c having a dome shape formed by continuously forming a semicircle instead of one side of the square shape. A bearing 85 is inserted into the rectangular bearing support surface 88b of the through hole 88c, and a cam 86 is inserted into the semicircular cam support surface 88a.

  As shown in FIGS. 5 to 7, the cam 86 serving as a cam member is centered on the rotation shaft 16 a of the stretching roller 16 via a cam base 92 that slides on the flange 91 when the intermediate transfer belt 13 meanders. Rotate in the direction of arrow C in FIG. As a result, the cam surface of the cam 86 comes into contact with the contact portion 95 of the cam support surface 88a, and the bearing 85 is raised in the direction of arrow D in FIG. As a result, the cam 86 serving as a cam member raises and tilts one end of the tension roller 16 on the control side R via the cam base 92 that slides on the flange 91 when meandering occurs in the intermediate transfer belt 13.

  As shown in FIG. 3, the other end portion on the fixed side Q of the stretching roller 16 is fixed except in the stretching direction of the intermediate transfer belt 13 (in the direction of arrow T in FIG. 3) (other than the stretching direction). That is, the bearing 83 that rotatably supports the rotating shaft 16a of the stretching roller 16 so that the other end portion on the fixed side Q of the stretching roller 16 does not move in the up-and-down direction as shown by the arrow D direction in FIG. Is locked and fixed by a claw portion 82b provided on the slide member 82.

  As shown in FIG. 5, the other end of the tension spring 81 whose one end is locked to the main body frame 80 e of the belt conveying device 80 is locked to one end portion of the slide member 87. The tension roller 16 urges the intermediate transfer belt 13 in the tension direction (the direction of arrow T in FIG. 5) via the slide member 87, the cam control member 88, the bearing 85, and the like by the extension force of the tension spring 81. A tension force is generated on the slide member 87.

  A rib 90 is provided on the inner peripheral surface of the intermediate transfer belt 13 so as to start the belt meandering control device 4 shown in FIGS. 5 to 7 when meandering occurs in the intermediate transfer belt 13. A slide member 87 on the control side R of the tension roller 16 shown in FIG. 5 stretches the intermediate transfer belt 13 so as to be movable in the same direction as the slide member 82 on the fixed side Q of the tension roller 16 shown in FIG.

<Belt meandering control device 4>
FIG. 6 is an exploded perspective view showing the configuration of the belt meandering control device 4 that suppresses meandering when meandering occurs in the intermediate transfer belt 13. The cam base 92 fitted to the rotary shaft 16a of the tension roller 16 is provided with a convex portion 92a protruding in the direction of the rotary shaft 16a. The convex portion 92 a of the cam base 92 is fitted into a slit 86 a provided at the end of the cylindrical portion 86 b of the cam 86. As a result, the cam base 92 and the cam 86 are configured to be integrally rotatable about the rotation shaft 16a of the stretching roller 16.

  Between the cam base 92 and the cam 86, a flange 91 in which a through hole 91a is fitted into the cylindrical portion 86b of the cam 86 is disposed. When the rib 90 provided protruding from the inner peripheral surface of the intermediate transfer belt 13 comes into contact with the flange portion 91b of the flange 91, the flange 91 rotates integrally with the rib 90.

  The rotation of the flange 91 causes the cam base 92 that slides with the flange 91b of the flange 91 to rotate. The contact surface of the flange 91b of the flange 91 and the contact surface of the cam base 92 are configured to have a predetermined coefficient of friction.

  The convex portion 92a of the cam base 92 is fitted and locked in a slit 86a formed at the end of the cylindrical portion 86b of the cam 86. Then, the cam 86 rotates integrally with the cam base 92 in the direction of arrow C in FIG.

  FIG. 7 is an explanatory side view showing the configuration of the belt meandering control device 4 as viewed from the control side R of the stretching roller 16. The intermediate transfer belt 13 starts meandering, and a rib 90 provided so as to protrude from the inner peripheral surface of the intermediate transfer belt 13 comes into contact with the flange portion 91 b of the flange 91. Then, the cam 86 rotates in the direction of arrow C in FIG. 7 about the rotation shaft 16a of the stretching roller 16 via the cam base 92 shown in FIG. At this time, the cam 86 contacts the cam support surface 88a of the cam control member 88, and the cam 86 rotating in the direction of arrow C in FIG. 7 is supported by the cam support surface 88a.

  The rotational force of the cam 86 that rotates in the direction of the arrow C in FIG. 7 about the rotation shaft 16a of the tension roller 16 causes the bearing 85 to act on the contact portion 95 between the cam surface of the cam 86 and the cam support surface 88a. It acts as a force in the direction of raising in the direction of arrow D in FIG.

  The bearing 85 is supported by a bearing support surface 88b formed on the cam control member 88, and moves upward along the bearing support surface 88b in the direction of arrow D in FIG. As a result, the end on the control side R of the rotating shaft 16a of the tension roller 16 moves upward in the direction of arrow D in FIG.

  When the bearing 85 abuts against the top surface 88b1 of the bearing support surface 88b, the abutment surface of the flange 91b of the flange 91 and the abutment surface of the cam base 92 idle.

  FIGS. 8A and 8B are perspective explanatory views showing the configuration of the belt conveying device 80 in which the posture of the tension roller 16 before and after meandering control of the intermediate transfer belt 13 is shown in cross section. 8 (a) and 8 (b), the intermediate transfer belt 13 is rotated in the direction of arrow A in FIGS. 8 (a) and 8 (b). When the meandering of the intermediate transfer belt 13 occurs in the direction of arrow E in FIG. 8A, the rib 90 projecting from the inner peripheral surface of the intermediate transfer belt 13 and the flange 91b of the flange 91 come into contact with each other.

  Then, the cam 86 that comes into contact with the cam support surface 88a of the cam control member 88 serving as a fixed portion rotates about the rotation shaft 16a of the stretching roller 16 in the direction of arrow C in FIG. Is moved upward in FIG. 8B. FIG. 8B shows a state after the end of the tension roller 16 on the control side R has moved upward in FIG. 8B.

  As shown in FIG. 8B, when the end of the tension roller 16 on the control side R moves upward, the end of the tension roller 16 reaches the angle θ shown in FIG. 8B. Tilt upwards only. For this reason, the intermediate transfer belt 13 that rotates in the direction of arrow A in FIG. 8B generates a control force that moves in the direction of arrow F in FIG.

  FIGS. 9A and 9B are side explanatory views showing the posture of the cleaner 17 serving as a cleaning means before and after meandering control of the intermediate transfer belt 13. As shown in FIG. 10, the cleaning blade 96 provided in the cleaner 17 of the present embodiment is provided so as to be rotatable around a rotation shaft 100 provided through a side surface of a cleaning box 98 provided in the cleaner 17. The pressure member 97 is fixed integrally.

  At the end of the pressure member 97 opposite to the cleaning blade 96, the other end of the compression spring 104 with one end locked to a device frame (not shown) is locked. The cleaning blade 96 is slid on the outer peripheral surface of the intermediate transfer belt 13 wound around the tension roller 16 by being urged in the clockwise direction in FIG. Abuts in a movable manner.

  On the other hand, as shown in FIGS. 9 (a) and 9 (b), the rotating shaft 16 a of the stretching roller 16 is inserted into a through hole 98 b provided in the side surface of the cleaning box 98. The rotary shaft 16a is provided so as to be rotatable.

  As shown in FIG. 9A, the cleaner 17 before the meandering control of the intermediate transfer belt 13 is as follows. The frictional force between the outer peripheral surface of the intermediate transfer belt 13 and the cleaning blade 96 shown in FIG. 10 is urged and rotated counterclockwise in FIG. 9A around the rotation shaft 16a of the tension roller 16. At this time, the abutting portion 98c provided at the lower end portion of the cleaning box 98 abuts against the abutting portion 102 of the slide member 87, and the rotating shaft 16a of the tension roller 16 of the cleaner 17 is shown in FIG. Counterclockwise rotation stops.

  FIG. 9B shows the posture state of the cleaner 17 after the meandering control of the intermediate transfer belt 13. The belt meandering control device 4 of the intermediate transfer belt 13 moves the end of the tension roller 16 on the control side R upward in FIG. 9B. Then, the cleaner 17 moves upward in FIG. 9B integrally with the rotary shaft 16a of the tension roller 16.

  As a result, the contact portion 98 d provided at the upper end of the cleaning box 98 abuts against the contact portion 103 of the slide member 87. Accordingly, the cleaner 17 whose upward movement is restricted in FIG. 9B rotates in the direction of arrow H in FIG. 9B with the contact portion 103 of the slide member 87 as a fulcrum.

  At this time, the left end portion in FIG. 9 of the cleaner 17 on the control side R of the stretching roller 16 is compared with the state before meandering control of the intermediate transfer belt 13 shown in FIG. Lifts by the indicated angle φ.

  FIG. 10 is an explanatory side view showing the configuration of the belt conveyance device 80 and the cleaning blade 96 of the cleaner 17. A force acts between the outer peripheral surface of the intermediate transfer belt 13 and the cleaning blade 96 in the tangential direction of the intermediate transfer belt 13 wound around the tension roller 16 indicated by the arrow J in FIG. ing. The force in the direction of arrow J shown in FIG. 10 is a force that rotates the cleaner 17 in the counterclockwise direction of FIG. 9A around the rotating shaft 16a of the stretching roller 16 as shown in FIG. 9A. Works.

  In this embodiment, as shown in FIG. 8B, the belt meandering control device 4 causes the end of the tension roller 16 of the intermediate transfer belt 13 on the control side R to incline upward in FIG. 8B. . Further, as shown in FIG. 10, the cleaning blade 96 rotates around the rotation shaft 100 in the clockwise direction of FIG.

  Then, the downward frictional force of FIG. 10 by the cleaning blade 96 acting on the outer peripheral surface of the intermediate transfer belt 13 and the upward inclination of the end of the tension roller 16 on the control side R in FIG. The action works while balancing each other. For this reason, it is possible to suppress excessive control of the meandering of the intermediate transfer belt 13 due to excessive swinging of the end of the tension roller 16 on the control side R.

  The belt meandering control device 4 shown in FIG. 8B tilts the end of the tension roller 16 of the intermediate transfer belt 13 on the control side R upward, and the outer peripheral surface of the intermediate transfer belt 13 shown in FIG. The downward frictional force of the working cleaning blade 96 is always acting. As a result, meandering control of the intermediate transfer belt 13 with high responsiveness can be performed.

  In this embodiment, when the meandering of the intermediate transfer belt 13 occurs in a direction in which the rib 90 protruding from the inner peripheral surface of the intermediate transfer belt 13 contacts the outer peripheral surface of the flange 91b of the flange 91, the cam 86 The tension roller 16 is inclined by the action.

  Further, when the meandering of the intermediate transfer belt 13 occurs in the direction in which the rib 90 projecting from the inner peripheral surface of the intermediate transfer belt 13 is separated from the outer peripheral surface of the flange 91b of the flange 91, the following occurs. The direction opposite to the inclination direction in which the tension roller 16 is inclined by the action of the cam 86 by the action of the friction force between the cleaning blade 96 of the cleaner 17 serving as a cleaning means and the outer peripheral surface of the intermediate transfer belt 13. The tension roller 16 is inclined to the side.

  Next, the relationship between the winding angle of the intermediate transfer belt 13 with respect to the outer peripheral surface of the stretching roller 16 and the contact position where the cleaning blade 96 contacts the outer peripheral surface of the intermediate transfer belt 13 will be described with reference to FIGS. To do.

  FIG. 11 is a cross-sectional explanatory view showing the configuration of the intermediate transfer belt 13 wound around the outer peripheral surface of the tension roller 16 and the cleaning blade 96 in a state where the intermediate transfer belt 13 is stopped. The tension roller 16 of this embodiment is in contact with the intermediate transfer belt 13 within the range of the winding angle Ψ around the rotation center 16b of the tension roller 16 to apply tension to the intermediate transfer belt 13. .

  As shown in FIG. 11, the cleaning blade 96 is fixed to a pressurizing member 97 provided so as to be rotatable about a rotation shaft 100. The pressurizing member 97 is urged in the clockwise direction in FIG. 11 around the rotation shaft 100 by a compression spring 104 that is locked at one end to an apparatus frame (not shown).

  The cleaning blade 96 rotates around the rotation shaft 100 in the clockwise direction in FIG. 11 by the extension force of the compression spring 104 and contacts the outer peripheral surface of the intermediate transfer belt 13. Accordingly, the residual toner 6 on the outer peripheral surface of the intermediate transfer belt 13 is scraped off and removed by the cleaning blade 96.

  FIG. 12 is a cross-sectional explanatory view showing the configuration of the intermediate transfer belt 13 wound around the outer peripheral surface of the stretching roller 16 and the cleaning blade 96 in a state where the intermediate transfer belt 13 is rotated. As shown in FIG. 12, the frictional force of the cleaning blade 96 acting on the outer peripheral surface of the intermediate transfer belt 13 is applied downward in FIG. For this purpose, as shown in FIG. 12, it is necessary to bring the cleaning blade 96 into contact with the outer peripheral surface of the intermediate transfer belt 13 in the range of the angle Ψ / 2 around the rotation center 16 b of the stretching roller 16.

  In the present embodiment, the cleaning blade 96 of the cleaner 17 serving as a cleaning unit is as follows. The region of the winding angle Ψ with respect to the intermediate transfer belt 13 around the rotation center 16b of the stretching roller 16 shown in FIGS. 11 and 12 in which the inner peripheral surface of the intermediate transfer belt 13 contacts the outer peripheral surface of the stretching roller 16 is shown. is there.

  The cleaning blade 96 is located on the upstream side of the intermediate transfer belt 13 in the conveyance direction indicated by the arrow A in FIGS. 11 and 12 from the substantially central portion 13b along the circumferential direction of the stretching roller 16 in the region of the winding angle Ψ. Abutting on the outer peripheral surface of the transfer belt 13.

  As in this embodiment, with respect to the winding angle Ψ of the intermediate transfer belt 13 with respect to the outer peripheral surface of the tension roller 16 shown in FIG. 12, the cleaning blade 96 is moved within the range of the winding start point 13a to Ψ / 2. Is pressed against the tension roller 16. As a result, meandering control of the intermediate transfer belt 13 can be performed without changing the cleaning performance of the cleaning blade 96.

  After the image formation, the residual toner 6 on the outer peripheral surface of the intermediate transfer belt 13 is removed. For this reason, the cleaning blade 96 is pressed against the stretching roller 16 with the intermediate transfer belt 13 interposed therebetween, and the residual toner 6 scraped and collected by the cleaning blade 96 is conveyed to a collected toner container disposed inside the main body of the image forming apparatus 1. . In this configuration, it is desirable to fix one end of the cleaning unit to the main body of the image forming apparatus 1.

  This is to prevent the toner collected at the connecting portion between the cleaning unit and the main body of the image forming apparatus 1 from leaking. When the technique of Patent Document 1 is applied to such an image forming apparatus 1, one end of the stretching roller 16 is fixed, and therefore control is performed only by the other end. That is, a recovery toner conveyance path and a recovery toner container are disposed at one end of the stretching roller 16, and a control device for the stretching roller 16 is disposed at the other end, so that the main body of the image forming apparatus 1 cannot be increased in size.

  In this embodiment, the meandering control of the intermediate transfer belt 13 is performed by the action of the rib 90 protruding from the inner peripheral surface of the intermediate transfer belt 13, the flange 91 inserted through the rotation shaft 16a of the stretching roller 16, the cam 86, and the like. This is performed by tilting the tension roller 16. In order to prevent an excessive tilting operation of the stretching roller 16, the frictional force between the outer peripheral surface of the intermediate transfer belt 13 and the cleaning blade 96 is used.

  In the present embodiment, when the intermediate transfer belt 13 approaches the cam 86 side (cam member side) in the belt width direction of the intermediate transfer belt 13, the stretching roller 16 is inclined by the cam 86. When the intermediate transfer belt 13 approaches the cam 86 side (cam member side) in the belt width direction, the cam 86 is in contact with the flange 91 that rotates on the inner peripheral surface of the intermediate transfer belt 13 and rotates. The tension roller 16 is inclined by moving.

  When the intermediate transfer belt 13 is moved away from the cam 86, the tension roller 16 is inclined in the direction opposite to the inclination direction by the action of the frictional force between the cleaning blade 96 and the intermediate transfer belt 13.

  In this embodiment, since the structure is simple, the belt meandering control device 4 that controls meandering of the intermediate transfer belt 13 can be mounted without increasing the size of the main body of the image forming apparatus 1. Further, the tilting operation of the tension roller 16 and the frictional force between the outer peripheral surface of the intermediate transfer belt 13 and the cleaning blade 96 are always generated when the intermediate transfer belt 13 meanders. Therefore, it is possible to perform meandering control with high responsiveness to fluctuations in meandering of the intermediate transfer belt 13.

  In the above-described embodiment, an example of the belt conveyance device 80 configured to suppress the meandering of the intermediate transfer belt 13 has been described. However, the belt conveyance device 80 configured to suppress the meandering of the sheet conveyance belt that conveys the sheet P as a recording material. It is also possible to configure as.

13 ... Intermediate transfer belt (endless belt)
14… Drive roller (drive rotating body)
16… Tension roller (Tension stretcher)
86… Cam (cam member)
90… ribs
91… Flange
96… Cleaning blade (rubbing member)

Claims (8)

An endless belt that rotates,
A driving rotating body that stretches the endless belt and rotates the endless belt;
A tension rotating body that stretches the endless belt;
A rubbing member that contacts and rubs against the outer peripheral surface of the endless belt;
A cam member for inclining the tension rotating body using the force of the endless belt when the endless belt is close to a belt width direction orthogonal to the moving direction of the endless belt;
Have
In the belt width direction, when the endless belt approaches the cam member side, the tension rotating body is inclined by the cam member,
When the endless belt approaches the side away from the cam member, the tension rotating body is inclined in a direction opposite to the inclination direction by the action of frictional force between the sliding member and the endless belt. Belt conveyor device. Ribs provided to project from the inner peripheral surface of the endless belt;
A flange that is rotatably provided at one end side of the tension rotator, and rotates in contact with the rib;
Have
When the endless belt approaches the cam member side in the belt width direction, the cam member is configured to incline the tension rotating body by sliding with the flange rotating in contact with the rib. The belt conveyance device according to claim 1, wherein   The belt conveying device according to claim 1, wherein the endless belt is a transfer belt for transferring a toner image from an image carrier to a recording material.   The belt conveyance device according to claim 3, wherein the rubbing member is a cleaning blade that collects toner on an outer peripheral surface of the transfer belt. The other end portion of the tension rotating body is disposed on a fixed side that is fixed except in the tension direction of the endless belt,
5. The belt conveyance device according to claim 1, further comprising a discharge port that discharges toner collected by the rubbing member on the fixed side of the rubbing member.   The rubbing member is upstream of the endless belt in the conveyance direction from a substantially central portion along the circumferential direction of the tension rotating body in a region where the inner circumferential surface of the endless belt is in contact with the outer circumferential surface of the tension rotating body. The belt conveying device according to claim 1, wherein the belt conveying device is in contact with an outer peripheral surface of the endless belt on the side.   An image forming apparatus comprising the belt conveyance device according to claim 1. An image forming apparatus comprising the belt conveyance device according to claim 5,
The image forming apparatus, wherein the discharge port is connected to a toner discharge path provided in a main body of the image forming apparatus.

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