JP2020196613A - Cleaning device and image formation apparatus having the same - Google Patents

Abstract

To prevent a web for cleaning a conveyance roller of a sheet from being reversely fed or unnecessarily forward-fed.SOLUTION: A cleaning unit 70A is brought into contact with the surface of a register lower roller 32 to clean the surface. The cleaning unit 70A comprises: a belt-like web W which forms a contact surface WA contacting the register lower roller 32; a press roller 72 which presses the web W against the register lower roller 32; and a web driven roller 71 and a web driving roller 73 which perform delivery and take-up of the web W. A press roller shaft 72S of the press roller 72 is provided with a torque limiter 72T which permits the rotation of the press roller 72 when the first torque is generated in the press roller 72 at the delivery and take-up of the web W and restricts the rotation of the press roller 72 when the second torque larger than the first torque is generated in the press roller 72.SELECTED DRAWING: Figure 4

Description

The present invention relates to a cleaning device for cleaning a sheet transport roller and an image forming device including the cleaning device.

In an image forming apparatus such as a printer, a sheet is conveyed to a predetermined image forming position, and an image is formed on the sheet at the image forming position. Generally, a pair of resist rollers feeds the sheet to the image forming position. The resist roller pair has a roller length corresponding to the width of the sheet and forms a nip portion through which the sheet passes. When the tip of the sheet comes into contact with the nip while the rotation of the resist roller pair is stopped, the skew of the sheet is corrected. After that, when the resist roller pair rotates, the sheet is carried into the nip portion, and then the sheet is sent out at an appropriate image formation timing at the image formation position.

Patent Documents 1 and 2 disclose a cleaning device that removes paper dust adhering to the surface of a resist roller. The cleaning device includes a rolled web and a pressing roller that presses the web against the surface of a resist roller. As the webs are sequentially fed, the new web surface comes into contact with the surface of the resist roller to remove paper dust.

Japanese Unexamined Patent Publication No. 2004-345805 Japanese Unexamined Patent Publication No. 2006-117420

In the cleaning device as described above, foreign matter such as paper dust wiped off from the resist roller may be blocked on the web near the nip portion between the pressing roller and the resist roller. If the web is properly wound, the dammed paper dust is also wound by the web winding roller together with the web. However, a large torque may act on the resist roller due to factors such as sheet jam being generated in the resist roller and the sheet being pulled out. In this case, the pressing roller also rotates in a driven manner, and if the rotation direction of the resist roller is the direction in which the web is fed backward, the blocked paper dust may be caught in the nip portion and adhere to the resist roller again. is there. Further, if the rotation direction is the direction in which the web is progressively fed, the web is unnecessarily sent out and consumed, and the web is slackened, so that the progressive feed of the web by the web winding roller is caused by the slack. It will be hindered only during the resolution period.

An object of the present invention is to provide a cleaning device in which a web for cleaning a sheet transport roller is not forward-fed or unnecessarily forward-fed, and an image forming apparatus to which the web is applied.

The cleaning device according to one aspect of the present invention is a cleaning device capable of cleaning the surface of a transport roller that transports a sheet in an image forming apparatus, and is a contact surface extending along the axial direction of the transport roller. The contact surface is in contact with the surface of the transport roller to clean the surface, and the cleaning portion includes a strip-shaped web forming the contact surface that abuts the transport roller. Includes a pressing roller that presses the web against the transport roller, a feeding roller that unwinds the web and a take-up roller that winds the web so that a portion of the web that abuts on the transport roller changes. On the rotation shaft of the pressing roller, the first torque generated in the pressing roller during feeding and winding of the web allows the pressing roller to rotate around the rotation axis, but is larger than the first torque. When a second torque is generated on the pressing roller, a torque limiter that limits the rotation of the pressing roller around the rotation axis is arranged.

According to this cleaning device, the web is sequentially wound from the feeding roller to the winding roller through the pressing points on the transport roller by the pressing roller. Since the torque limiter is arranged on the rotation axis of the pressing roller, the pressing roller is driven to rotate in response to the movement of the web when the web is unwound and wound to generate the first torque. Achieve smooth feeding and winding. On the other hand, when the second torque is generated, the rotation of the pressing roller is restricted. For example, even when a large torque acts on the pressing roller via the conveying roller due to sheet pulling out during jam processing or the like, the pressing roller does not rotate in a driven manner. Therefore, it is possible to prevent the web from being fed backward or unnecessarily forward, and it is possible to solve the problem of the once wiped foreign matter reattaching to the transport roller and the web being loosened.

In the above-mentioned cleaning device, the take-up roller winds the web so that the take-up direction of the web is opposite to the normal rotation direction of the convey roller that conveys the sheet. It is desirable that the rotation shaft of the take-up roller is provided with a one-way clutch that allows only rotation in the take-up direction.

According to this cleaning device, the back-feeding of the web is basically suppressed by the arrangement of the one-way clutch. However, a general one-way clutch has a play that allows a slight reverse rotation. Therefore, when a torque in the direction of back-feeding the web acts on the pressing roller via the transport roller, the web is slightly back-feeded. In this case, foreign matter such as paper dust dammed on the web near the nip portion between the pressing roller and the transport roller may be caught in the nip portion and then reattached to the transport roller. However, since the torque limiter is arranged on the rotation shaft of the pressing roller, it is possible to suppress even a slight reverse feed of the web due to the play of the one-way clutch.

In the above-mentioned cleaning device, it is desirable that a brake member for limiting the rotation of the feeding roller in the feeding direction is arranged on the rotating shaft of the feeding roller.

According to this cleaning device, the brake member basically suppresses excessive feeding from the feeding roller. However, when a large torque in the direction of progressively feeding the web acts on the pressing roller via the transport roller during jam processing or the like, the brake member alone may not be able to suppress the feeding of the web. In this case, the web will be loosened. However, since the torque limiter is arranged on the rotating shaft of the pressing roller, it is possible to suppress the progressive feed of the web, which cannot be suppressed only by the brake member.

The image forming apparatus according to another aspect of the present invention includes an apparatus main body, a conveying roller for conveying a sheet, an image forming portion for forming an image on the sheet, and the above-mentioned cleaning capable of cleaning the conveying roller. It is equipped with a device.

According to this image forming apparatus, since the conveying roller is cleaned by the cleaning apparatus, it is possible to prevent paper dust, toner, ink and the like from being transferred from the conveying roller to the image forming sheet.

The image forming apparatus further includes an upper resist roller that conveys the sheet toward the image forming portion in accordance with the image forming timing in the image forming portion, and the conveying roller is arranged below the upper resist roller. A lower resist roller that forms a nip portion through which the sheet passes with the upper resist roller and conveys the sheet toward the image forming portion in accordance with the image forming timing. It is desirable to clean the surface of the lower resist roller.

According to this image forming apparatus, by cleaning the surface of the lower resist roller by the cleaning apparatus, it is possible to prevent stains on the lower resist roller from being transferred to the sheet during, for example, double-sided printing.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a cleaning device in which a web for cleaning a sheet transport roller is not forward-fed or unnecessarily forward-fed, and an image forming apparatus to which the web is applied.

FIG. 1 is a schematic cross-sectional view showing an internal structure of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the periphery of the resist roller portion and the cleaning unit included in the image forming apparatus, and is a cross-sectional view of a state in which the cleaning unit is arranged at the cleaning position. FIG. 3 is a perspective view of the cleaning unit. FIG. 4 is a perspective view of the cleaning unit having a different perspective direction from that of FIG. FIG. 5 is a perspective view of the cleaning unit whose perspective direction is different from that of FIGS. 3 and 4. FIG. 6 is a sectional view taken along line VI-VI of FIG. FIG. 7 is a front view in which some members of the cleaning unit are omitted. FIG. 8 is a perspective view showing the internal structure of the cleaning unit. FIG. 9 is a perspective view of the cleaning unit and the web feeding mechanism. FIG. 10 is an enlarged perspective view of a part of the cleaning unit. FIG. 11 is an enlarged perspective view of a part of the cleaning unit. FIG. 12 is a cross-sectional view of the same location as in FIG. 2, and is a cross-sectional view of a state in which the cleaning unit is arranged at the attachment / detachment position. FIG. 13 is a perspective view showing the positional relationship between the resist roller portion and the cleaning unit in a state where the cleaning unit is arranged at the attachment / detachment position. FIG. 14 is a perspective view showing the positional relationship between the resist roller portion and the cleaning unit in a state where the cleaning unit is arranged at the cleaning position. FIG. 15 is a schematic view for explaining the basic operation of the resist roller pair and the cleaning unit. FIG. 16 is a cross-sectional view showing a situation in which a strong torque in the reverse rotation direction acts on the pressing roller. FIG. 17 is a schematic diagram for explaining a defect when the situation of FIG. 16 occurs. FIG. 18 is a cross-sectional view showing a situation in which a strong torque in the forward rotation direction acts on the pressing roller. FIG. 19 is a schematic diagram for explaining a defect when the situation of FIG. 18 occurs.

[Overall structure of image forming apparatus]
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing the internal structure of the image forming apparatus 1 according to the embodiment of the present invention. The image forming apparatus 1 is an inkjet printer that ejects ink droplets to form an image on the sheet S. The image forming apparatus 1 includes an apparatus main body 10, a paper feeding unit 20, a resist roller unit 30, a belt transport unit 40, an image forming unit 50, and a curl correction unit 60.

The device main body 10 is a box-shaped housing that houses various devices for forming an image on the sheet S. Inside the main body 10 of the apparatus, a first transport passage 11, a second transport passage 12, and a third transport passage 13, which serve as transport passages for the sheet S, are formed.

The paper feeding unit 20 feeds the sheet S to the first transport path 11. The paper feed unit 20 includes a paper feed cassette 21 and a paper feed roller 22. The paper feed cassette 21 is removable from the device main body 10 and houses the sheet S inside. The paper feed roller 22 is arranged on the right side of the upper end portion of the paper feed cassette 21. The paper feed roller 22 transports the sheet S housed in the paper feed cassette 21 to the downstream side of the first transport path 11.

The sheet S fed into the first transport path 11 reaches the resist roller portion 30 arranged at the downstream end of the first transport path 11 by the first transport roller pair 111 provided in the first transport path 11. Be transported. A paper feed tray 24 is arranged on the right side surface of the apparatus main body 10. The sheet S can be manually placed on the upper surface of the paper feed tray 24. The sheet S placed on the paper feed tray 24 is sent out toward the resist roller unit 30 by the paper feed roller 23.

The resist roller unit 30 is a device that conveys the sheet S carried in through the first transfer path 11 or the paper feed roller 23 toward the transfer belt 41 in the belt transfer unit 40 in the sheet transfer direction A1. The resist roller unit 30 and the belt transport unit 40 transport the sheet S at different positions from each other. Details of the resist roller unit 30 will be described later.

The sheet S conveyed by the resist roller unit 30 is conveyed in the sheet transfer direction A2 by the belt transfer unit 40. The sheet transport directions A1 and A2 are in the left direction in FIG. The belt transport unit 40 is arranged below the image forming unit 50. The belt transport unit 40 transports the sheet S transported by the resist roller unit 30 so that the sheet S passes below the image forming unit 50 in the sheet transfer direction A2 toward the curl correction unit 60. The belt transport unit 40 includes a transport belt 41, a first support roller 421, a second support roller 422, a third support roller 423, a pair of fourth support rollers 424, and a suction unit 43.

The transport belt 41 is an endless belt having a predetermined width in the front-rear direction and extending in the left-right direction. The transport belt 41 is arranged so as to face the image forming portion 50, and transports the sheet S in the sheet transport direction A2 on the outer peripheral surface 411. An image forming position at which image formation is formed on the sheet S is set by the image forming portion 50 on the orbital movement path of the transport belt 41.

The transport belt 41 is stretched on a first support roller 421, a second support roller 422, a third support roller 423, and a pair of fourth support rollers 424. Inside the stretched transport belt 41, a suction portion 43 is arranged so as to face the inner peripheral surface 412 of the transport belt 41. The first support roller 421 is rotationally driven by a drive motor (not shown) to orbit the transport belt 41 in a predetermined circumferential direction. The transport belt 41 has a plurality of suction holes penetrating in the thickness direction from the outer peripheral surface 411 to the inner peripheral surface 412.

The suction unit 43 is arranged so as to face the image forming unit 50 via the transport belt 41. The suction unit 43 causes the sheet S to be brought into close contact with the outer peripheral surface 411 of the transfer belt 41 by generating a negative pressure between the sheet S held on the outer peripheral surface 411 of the transfer belt 41 and the transfer belt 41. The suction unit 43 includes a belt guide member 431, a suction housing 432, a suction device 433, and an exhaust duct 434.

The belt guide member 431 guides the orbital movement of the transport belt 41 linked to the rotation of the first support roller 421 between the first support roller 421 and the second support roller 422. The belt guide member 431 is formed with a groove and a through hole. The suction unit 43 sucks air from the space above the conveyor belt 41 through the groove and the through hole of the belt guide member 431 and the suction hole of the conveyor belt 41. Due to the suction force generated by this suction, an air flow (suction wind) toward the suction portion 43 is generated in the space above the transport belt 41. When the sheet S is conveyed onto the transfer belt 41 by the resist roller portion 30 and covers a part of the outer peripheral surface 411 of the transfer belt 41, a suction force (negative pressure) acts on the sheet S, and the sheet S is transferred to the transfer belt 41. It is in close contact with the outer peripheral surface 411 of the.

The suction housing 432 is a box-shaped housing having an opening on the upper side, and is arranged below the transport belt 41 so that the opening on the upper side is covered by the belt guide member 431. The suction housing 432 defines the suction space 432A in cooperation with the belt guide member 431. An opening 432B is formed in the bottom wall portion of the suction housing 432, and a suction device 433 is arranged corresponding to the opening 432B. An exhaust duct 434 is connected to the suction device 433. The exhaust duct 434 is connected to an exhaust port (not shown) provided in the apparatus main body 10.

An image forming unit 50 is arranged on the upper side of the belt transport unit 40. The image forming unit 50 performs an image forming process on the sheet S which is conveyed in the sheet conveying direction A2 while being held on the outer peripheral surface 411 of the conveying belt 41 to form an image. In the present embodiment, the image forming method of the image forming unit 50 is an inkjet method, and ink droplets are ejected to form an image on the sheet S.

The image forming unit 50 includes a line head 51 (51Bk, 51C, 51M, 51Y). The line head 51Bk ejects black ink droplets, the line head 51C ejects cyan ink droplets, the line head 51M ejects magenta ink droplets, and the line head 51Y ejects yellow ink droplets. The line heads 51Bk, 51C, 51M, and 51Y are arranged side by side from the upstream side to the downstream side in the sheet transport direction A1. Each of the line heads 51Bk, 51C, 51M, and 51Y ejects ink droplets onto the sheet S transported in the sheet transport direction A2 while being held on the outer peripheral surface 411 of the transport belt 41, and displays an image on the sheet S. Form. As a result, an image is formed on the sheet S.

The sheet S on which the image is formed is conveyed by the transport belt 41, and is carried into the curl correction section 60 while being guided by the sheet discharge guide section 44. The curl correction unit 60 is arranged on the downstream side of the sheet transport direction A2 of the transport belt 41 with the sheet discharge guide portion 44 interposed therebetween. The curl correction unit 60 corrects the curl of the sheet S while transporting the sheet S on which the image is formed to the downstream side.

The sheet S whose curl has been corrected by the curl correction unit 60 is sent to the second transport path 12. The second transport path 12 extends along the left side surface of the apparatus main body 10. The sheet S delivered to the second transport path 12 is transported toward the paper ejection port 12A formed on the left side of the apparatus main body 10 by the second transport roller pair 121 provided in the second transport path 12. It is discharged onto the paper ejection unit 14 from the paper ejection port 12A.

On the other hand, when double-sided printing is applied to the sheet S, the sheet S for which the image forming process on the front surface side has been completed is sent out from the second transport path 12 to the sheet reversing portion 15. The sheet reversing portion 15 is a transport path branched in the middle of the second transport path 12, and is a portion where the sheet S is switched back. The sheet S whose front and back sides are reversed by the sheet reversing portion 15 is sent to the third transport path 13, and is back-fed by the third transport roller pair 131 provided in the third transport path 13. After that, the sheet S is resupplied onto the outer peripheral surface 411 of the transport belt 41 again in a state where the front and back sides are reversed via the resist roller portion 30. The resupplied sheet S is subjected to image forming processing on the back surface side by the image forming portion 50 while being conveyed by the conveying belt 41. The sheet S for which double-sided printing has been completed passes through the second transport path 12 and is discharged from the paper ejection port 12A onto the paper ejection unit 14.

FIG. 2 is a cross-sectional view of the periphery of the resist roller portion 30 and the cleaning unit 70. The resist roller unit 30 conveys the sheet S toward the image forming unit 50 at the timing of image formation in the image forming unit 50. The resist roller unit 30 has a resist housing 30H and a resist roller pair including a resist upper roller 31 (upper resist roller) and a resist lower roller 32 (transfer roller, lower resist roller) for conveying a sheet. The resist housing 30H is mounted on the apparatus main body 10 and rotatably supports the resist upper roller 31 and the resist lower roller 32. The sheet S is carried into the resist housing 30H into the nip portion of the resist roller pair as shown by the arrow in FIG. The resist roller unit 30 has a roller drive unit (not shown) that rotationally drives the resist upper roller 31 and the resist lower roller 32.

The resist upper roller 31 is a roller arranged on the upper side of the resist roller pair. The resist roller 31 is made of a metal roller. The resist lower roller 32 is a roller arranged on the lower side of the resist roller pair. The under-resist roller 32 is made of a rubber roller made of EPDM (ethylene propylene diene rubber) or the like, and a PFA (tetrafluoroethylene / perfluoroalkoxyethylene copolymer resin) tube is fitted on the outer peripheral surface thereof. The resist lower roller 32 forms a nip portion through which the sheet S passes with the resist upper roller 31, and conveys the sheet S toward the image forming portion 50 in accordance with the image forming timing.

As shown in FIG. 2, the straight line L connecting the center of the upper resist roller 31 and the center of the lower resist roller 32 is inclined at an acute angle (for example, 10 degrees) with respect to the vertical direction. In other words, the lower resist roller 32 is located at a position shifted upstream of the resist upper roller 31 in the transport direction of the sheet S. The inclination of the straight line L is also due to the fact that the resist housing 30H itself is installed so as to be inclined upward to the right.

When the above-mentioned double-sided printing is performed, the single-sided printed sheet S is turned upside down and carried into the nip portion of the resist roller pair. Therefore, the under-resist roller 32 comes into contact with the printed surface of the sheet S, and undried ink may adhere to the surface of the under-resist roller 32. In this case, when the subsequent sheet S passes through the resist roller pair, there is a problem that the ink adhering to the resist lower roller 32 is transferred. Further, the resist lower roller 32 located on the lower side of the resist roller pair is a roller to which foreign matter including paper dust easily adheres.

[Cleaning device]
In view of the above circumstances, the image forming apparatus 1 of the present embodiment includes a cleaning apparatus 7. The cleaning device 7 is capable of cleaning the surface of the roller 32 under the resist. The cleaning device 7 has a cleaning unit 70 and a moving mechanism 75. The moving mechanism 75 can move the cleaning unit 70 between at least the cleaning position (FIG. 2) and the attachment / detachment position (FIG. 12).

3 to 5 are perspective views of the cleaning unit 70 of the image forming apparatus 1 according to the present embodiment. FIG. 6 is a sectional view taken along line VI-VI of FIG. FIG. 7 is a front view showing the cleaning unit 70 with some members omitted. FIG. 8 is a perspective view showing the internal structure (cleaning unit 70A) of the cleaning unit 70.

The cleaning unit 70 includes a cleaning unit 70A and a cleaning housing 70H. The cleaning unit 70A has a contact surface WA extending along the axial direction of the roller 32 under the resist. The cleaning unit 70A is arranged so that the contact surface WA is in contact with the surface of the roller 32 under the resist from below, and the contact surface WA is cleaned so as to wipe the surface.

The cleaning housing 70H supports the cleaning portion 70A. The cleaning housing 70H has a front wall 701, a rear wall 702, a connection wall 703, a pair of unit fulcrum pins 70P, a seat member 704, and a pair of guide rollers 705. The front wall 701, the rear wall 702, and the connecting wall 703 of the cleaning housing 70H are made of a metal material (magnetic material).

The front wall 701 and the rear wall 702 are arranged so as to face each other in the front-rear direction (axial direction of the roller under resist 32) and support the cleaning portion 70A. The connecting wall 703 connects the front wall 701 and the rear wall 702 along the front-rear direction. The connection wall 703 has a side wall 703A forming the upper right side surface of the cleaning housing 70H and a bottom wall 703B forming the bottom surface of the cleaning housing 70H (FIGS. 5 and 6).

The pair of unit fulcrum pins 70P project from the outer surfaces of the front wall 701 and the rear wall 702 in the front-rear direction, respectively. The unit fulcrum pin 70P is arranged in the lower left portion of the front wall 701 and the rear wall 702. Each unit fulcrum pin 70P has a two-stage cylindrical shape whose outer diameter decreases toward the tip.

The sheet member 704 is a film-like member forming the left side surface of the cleaning housing 70H, and is fixed to the bottom wall 703B (FIG. 6). The sheet member 704 prevents foreign substances such as paper dust and ink pigments collected in the cleaning unit 70 from being scattered in the apparatus main body 10.

The pair of guide rollers 705 are supported by the front wall 701 and the rear wall 702 above the unit fulcrum pin 70P, respectively, and include an outer peripheral surface that is rotatable around a central axis parallel to the front-rear direction. The guide roller 705 is arranged in the upper right portion of the front wall 701 and the rear wall 702. The pair of guide rollers 705 have a function of guiding the cleaning unit 70 when the cleaning unit 70 moves between the above-mentioned attachment / detachment position and the cleaning position.

The cleaning unit 70A includes a web W, a web driven roller 71 (feeding roller) rotatably supported by the front wall 701 and the rear wall 702, a pressing roller 72, and a web driving roller 73 (winding roller). Has. The web W is composed of a strip-shaped member that abuts on the surface of the roller 32 under resist and forms the above-mentioned contact surface WA that cleans the surface. As the web W, a cloth material such as a non-woven fabric can be used. In the present embodiment, as shown in FIGS. 6 and 8, the web W is in the form of a web roll WR previously wound in a roll shape, and is externally fitted to the web driven roller 71. The feeding tip of the web W is hung on the outer peripheral surface of the pressing roller 72 and then fixed to the outer peripheral surface of the web driving roller 73.

The pressing roller 72 abuts on the back surface of the web W and presses the front surface of the web W against the roller 32 under the resist. The pressing roller 72 is located between the web driven roller 71 and the web driving roller 73 on the moving path of the web W. The pressing roller 72 is an elastic roller in which an elastic body 72A is fitted on the peripheral surface of the pressing roller shaft 72S (rotating shaft). The pressing roller shaft 72S is a metal shaft, and for example, a shaft made of solid iron can be used. As the elastic body 72A, for example, a sponge member made of a foam of EPDM can be used. When the cleaning unit 70 is arranged at the above-mentioned cleaning position (FIG. 2), the pressing roller 72 abuts on the resist lower roller 32 with the web W in between. At this time, the center of the pressing roller 72 is located on the straight line L. The above-mentioned contact surface WA is a contact portion of the web W with respect to the under-resist roller 32 in the nip portion between the pressing roller 72 and the under-resist roller 32 formed on the straight line L, and extends in a strip shape in the front-rear direction. It is a part.

The web driven roller 71 is a roller capable of driven rotation around the axis of the driven roller shaft 71S (rotating shaft). The web driven roller 71 feeds out the web W so that the portion of the web W that abuts on the under-resist roller 32 changes. The web drive roller 73 winds up the unwound web W. The web drive roller 73 is a roller that rotates around the axis of the drive roller shaft 73S (rotational shaft), and a rotational driving force is applied to the drive roller shaft 73S from the drive system.

The pressing roller 72, the web driven roller 71, and the web driving roller 73 are provided with means for restricting rotation around their respective shafts. A torque limiter 72T that limits the rotation of the pressing roller 72 when a torque larger than a predetermined value acts on the pressing roller 72 is arranged on the pressing roller shaft 72S. A brake spring 71T (brake member; FIG. 10) that limits rotation of the web driven roller 71 in the feeding direction is arranged on the driven roller shaft 71S of the web driven roller 71. A one-way clutch 73T (FIG. 11) that allows only rotation of the web drive roller 73 in the winding direction is arranged on the drive roller shaft 73S of the web drive roller 73.

The cleaning unit 70 has a unit input gear 711 (FIG. 4), an interlocking gear 711T, a transmission gear 712, and a drive roller gear 713 as the drive system (FIG. 6). The unit input gear 711 is rotatably supported at the lower end and the right end of the front wall 701. The input gear shaft 711S of the unit input gear 711 penetrates the front wall 701 and extends to the inside (back side) of the front wall 701. The interlocking gear 711T is fixed to the input gear shaft 711S and rotates integrally with the unit input gear 711. The transmission gear 712 is rotatably supported inside the front wall 701 and is engaged with the interlocking gear 711T and the drive roller gear 713, respectively. The drive roller gear 713 is a gear fixed to the front end of the drive roller shaft 73S of the web drive roller 73.

FIG. 9 is a perspective view of the cleaning unit 70 and the web feeding mechanism 81. 10 and 11 are enlarged perspective views of a part of the cleaning unit 70. The cleaning device 7 further includes a web feeding mechanism 81 and a control unit 90. The web feeding mechanism 81 is attached to the apparatus main body 10 of the image forming apparatus 1. The web feeding mechanism 81 has a function of applying a rotational driving force to the driving roller shaft 73S to feed the web W of the cleaning unit 70. The web feeding mechanism 81 is connected to the cleaning unit 70 by arranging the cleaning unit 70 at the cleaning position (FIG. 2). The web feeding mechanism 81 includes a solenoid 811, a rotating arm 812, a third detection sensor 813, a first transmission gear 814, and a second transmission gear 815. The control unit 90 controls the operation of the solenoid 811.

The solenoid 811 receives a command signal from the control unit 90 to generate a driving force for moving the web W. The solenoid 811 includes a haunting shaft 811S. The haunting shaft 811S haunts the main body of the solenoid 811. The solenoid 811 is supported by a sheet metal drive frame (not shown) arranged in the apparatus main body 10.

The rotating arm 812 is rotatably supported by the apparatus main body 10. The rotating arm 812 has a shaft 812S, a first arm portion 812A, and a second arm portion 812B. The shaft 812S serves as a fulcrum in the rotation of the rotating arm 812. The shaft 812S is supported by the apparatus main body 10 so as to be rotatable around a rotation center axis extending in the front-rear direction. The rotating arm 812 has a first arm portion 812A and a second arm portion 812B. The first arm portion 812A extends to the right from the rotation center axis of the rotation arm 812. The tip of the first arm portion 812A is connected to the haunting shaft 811S. The second arm portion 812B extends downward from the rotation center axis of the rotation arm 812 on the side opposite to the first arm portion 812A. A detection piece 812C is arranged at the tip end portion (lower end portion) of the second arm portion 812B. Further, the rear end portion of the shaft 812S is provided with a gear portion 812T capable of rotating integrally with the shaft 81S. Further, the web feeding mechanism 81 has a first one-way clutch and a second one-way clutch (both not shown). The first one-way clutch is fixed inside the rotating arm 812 and fitted to the shaft 812S. Further, the second one-way clutch is fixed to the drive frame so as to be adjacent to the first one-way clutch and is fitted to the shaft 812S.

The third detection sensor 813 is fixed to the left end of the main body of the solenoid 811. The third detection sensor 813 is a PI sensor that detects the movement (rotation) of the detection piece 812C. The control unit 90 can detect the amount of feeding of the web roll WR according to the number of detections of the detection piece 812C output from the third detection sensor 813. Further, when the number of detections reaches a preset threshold number, the control unit 90 displays a message prompting the replacement of the cleaning unit 70 on a display unit (not shown) of the image forming apparatus 1.

The first transmission gear 814 is rotatably supported by the apparatus main body 10 and is engaged with the gear portion 812T. The first transmission gear 814 is composed of a two-stage gear. Similarly, the second transmission gear 815 is rotatably supported by the apparatus main body 10, engages with the rear gear portion of the two-stage gear of the first transmission gear 814, and is the above-mentioned unit input gear. Engages in 711.

FIG. 9 shows a state in which the haunting shaft 811S is immersed (contracted) with respect to the main body of the solenoid 811. When the control unit 90 inputs a command signal to the solenoid 811 from the state of FIG. 9, the haunting shaft 811S protrudes (extends) from the main body of the solenoid 811. As a result, the rotating arm 812 rotates counterclockwise in FIG. 9 around the shaft 812S. As a result, the rotational driving force is input to the unit input gear 711 of the cleaning unit 70 from the gear portion 812T, the first transmission gear 814, and the second transmission gear 815.

The rotational driving force input to the unit input gear 711 is further transmitted to the interlocking gear 711T, the transmission gear 712, and the drive roller gear 713, and the web drive roller 73 rotates by a preset rotation angle. As a result, the web W moves so as to be wound around the web drive roller 73. As a result, the portion of the web W that comes into contact with the under-resist roller 32 changes. That is, when the web W is wound, the contact surface WA that has been in contact with the resist lower roller 32 moves to the downstream side in the winding direction, and the portion of the web W that newly contacts the resist lower roller 32. Formes the next contact surface WA. When the rotation arm 812 rotates, the third detection sensor 813 detects the detection piece 812C, so that the unit input gear 711 rotates and the web W moves.

When the web W moves, the control unit 90 inputs a command signal to the solenoid 811 to contract the haunting shaft 811S again with respect to the main body of the solenoid 811. At this time, as shown in FIG. 11, the one-way clutch 73T provided on the drive roller shaft 73S of the web drive roller 73 functions, and the web drive roller 73 is prevented from rotating in the reverse direction. Therefore, every time the control unit 90 performs the infestation operation of the infestation shaft 811S, the web W moves to the web drive roller 73 side by a predetermined amount. As described above, in the present embodiment, it is possible to send out the web W from the web roll WR by utilizing the slight infestation stroke of the infestation shaft 811S of the solenoid 811.

With reference to FIG. 9, the above-mentioned torque limiter 72T is assembled on the front end side of the pressing roller shaft 72S of the pressing roller 72. When the web driven roller 71 and the web drive roller 73 feed and wind the web W, the torque limiter 72T rotates around the pressing roller shaft 72S of the pressing roller 72 with the normal torque (first torque) generated in the pressing roller 72. Allow rotation. On the other hand, the torque limiter 72T prohibits (limits) the rotation of the pressing roller 72 around the pressing roller shaft 72S (rotational axis) when a torque (second torque) larger than the normal torque is generated in the pressing roller 72. To do. This point will be described in detail later.

Further, referring to FIG. 10, the brake spring 71T described above is assembled to the driven roller shaft 71S of the web driven roller 71. The brake spring 71T is interposed between the E-ring 71R1 and the flange 71R2 in a compressed and deformed state. In FIG. 10, the front wall 701 of FIG. 9 is not shown. The flange 71R2 is a ring-shaped flange fixed to the pressing roller shaft 72S of the pressing roller 72. The rear end of the brake spring 71T is in contact with the flange 71R2. Further, the front end portion of the brake spring 71T is in contact with the back surface of the front wall 701. As a result, the compressive force of the brake spring 71T is applied to the pressing roller 72 via the flange 71R2, and the pressing roller 72 is prevented from rotating unnecessarily. As a result, even though the control unit 90 does not control the solenoid 811, the web W is prevented from being fed out from the pressing roller 72.

[Cleaning unit position change mechanism]
The moving mechanism 75 (FIG. 2) is a mechanism that enables the cleaning unit 70 to be moved between the cleaning position (FIG. 2) and the attachment / detachment position (FIG. 12) below the cleaning position. The moving mechanism 75 allows the web W of the cleaning portion 70A to come into contact with the resist lower roller 32 at the cleaning position, and the cleaning portion 70A is arranged downward with respect to the resist lower roller 32 at the attachment / detachment position. Moreover, the cleaning unit 70 is allowed to be attached to and detached from the apparatus main body 10. Further, the moving mechanism 75 can position the cleaning unit 70 at an intermediate position between the cleaning position and the attachment / detachment position. At this separation position, the cleaning unit 70A is separated downward from the resist lower roller 32, and the connection between the cleaning unit 70 and the web feeding mechanism 81 is released.

The moving mechanism 75 includes a cleaning unit rotating unit 45 and a unit driving unit 80 that rotate the cleaning unit 70 so as to change its posture between the cleaning position and the attachment / detachment position. The cleaning unit rotating portion 45 includes a rotating shaft 451 supported by a transport unit frame 40H that holds the belt transport unit 40, and a pair of front and rear rotating levers 452 attached to the front and rear of the rotating shaft 451. ..

The unit drive unit 80 generates a driving force that rotates the rotation shaft 451 around its central axis. With reference to FIG. 2, the unit drive unit 80 includes a motor (not shown) including a drive motor output shaft 801, a pulse plate 802, a first detection sensor 803, a second detection sensor 804, and a unit drive output gear 805 (FIG. 12). including. The rotational drive of the motor is controlled by the control unit 90 described above.

The pulse plate 802 is fixed to the drive motor output shaft 801 and rotates integrally with the drive motor output shaft 801. The first detection sensor 803 detects the amount of rotation of the pulse plate 802. Specifically, the first detection sensor 803 has a light emitting unit that emits detection light and a light receiving unit that receives the detection light. The pulse plate 802 has a plurality of slits opened at intervals along the direction of rotation thereof. As the pulse plate 802 rotates, the detection light is shielded by the slit, and the light receiving unit outputs a signal corresponding to the waveform to the control unit 90, whereby the drive motor output shaft 801 (pair of rotating levers 452). The amount of rotation is detected.

The second detection sensor 804 is composed of a known PI sensor and detects that the cleaning unit 70 is arranged at the cleaning position shown in FIG. In the present embodiment, the second detection sensor 804 detects the cleaning unit 70 when a part of the cleaning housing 70H enters between the light emitting portion and the light receiving portion of the second detection sensor 804.

The unit drive output gear 805 transmits the rotational driving force generated by the motor of the unit drive unit 80 to the rotation input gear of the cleaning unit rotation unit 45 (not shown). In the present embodiment, when the transport unit frame 40H is mounted on the apparatus main body 10, the rotation input gear and the unit drive output gear 805 are engaged with each other, and the rotation driving force can be transmitted to the rotation shaft 451. It becomes.

FIG. 12 is a cross-sectional view of the same portion as in FIG. 2, and is a cross-sectional view of a state in which the cleaning unit 70 is arranged at a detachable position. At this attachment / detachment position, the cleaning unit 70 is housed in the transport unit frame 40H, and can be pulled forward from the device main body 10 together with the belt transport unit 40. Therefore, when the cleaning unit 70A is consumed and needs to be replaced, the user changes the posture of the cleaning unit 70 to the detachable position and pulls out the transport unit frame 40H forward to replace the cleaning unit 70 with a new cleaning unit 70. Do the work to do.

FIG. 13 is a perspective view showing the positional relationship between the resist roller portion 30 and the cleaning unit 70 in a state where the cleaning unit 70 is arranged at the attachment / detachment position of FIG. A pin receiving portion 452P is formed on the rotating lever 452 of the cleaning unit rotating portion 45. The pin receiving portion 452P receives the unit fulcrum pin 70P (FIGS. 3 and 4) of the cleaning unit 70 along the direction orthogonal to the front-rear direction, and rotatably supports the unit fulcrum pin 70P.

With reference to FIGS. 12 and 13, the moving mechanism 75 has a guide portion 100G. The guide unit 100G allows the pair of guide rollers 705 to come into contact with each other as the rotation lever 452 rotates, and guides the cleaning unit 70 between the cleaning position and the attachment / detachment position. The guide portion 100G has a pair of front and rear first guide surfaces 101R and a pair of front and rear guide surfaces 102R. The front and rear pair of first guide surfaces 101R are each composed of the left side surfaces of the front and rear pair of guide frames 101 provided in the main body frame 100. The first guide surface 101R is inclined so as to guide the cleaning unit 70 (guide roller 705) to the right side as it advances upward. The pair of front and rear guide surfaces 102R are each composed of a resist housing 30H. The second guide surface 102R is slightly inclined so as to guide the cleaning unit 70 (guide roller 705) to the left side as it advances upward.

The moving mechanism 75 further has a pair of front and rear positioning portions 102S. The positioning unit 102S abuts on the guide roller 705 of the cleaning unit at the cleaning position, and positions the cleaning unit 70 so that the web W of the cleaning unit 70A can clean the roller 32 under the resist. The positioning portion 102S is continuously provided on the second guide surface 102R, and has an arc shape that follows the outer peripheral surface of the guide roller 705.

When the unit drive unit 80 rotates the rotation shaft 451 counterclockwise in FIG. 13, the rotation lever 452 also rotates counterclockwise. By this rotation, the cleaning unit 70 is lifted by the rotation lever 452. Then, due to the weight of the cleaning unit 70, the cleaning unit 70 tilts to the right with respect to the unit fulcrum pin 70P, and the pair of guide rollers 705 abut on the first guide surface 101R of the pair of guide portions 100G.

After that, when the pair of rotating levers 452 further rotate in response to the rotation of the rotating shaft 451, the cleaning unit 70 moves upward and to the right while the pair of guide rollers 705 are guided by the first guide surface 101R. To do. The unit fulcrum pin 70P is supported so as to be rotatable relative to the pin receiving portion 452P of the rotating lever 452. Therefore, the posture of the cleaning unit 70 changes with the upward movement, and the cleaning unit 70 rises smoothly according to the rotation of the rotation lever 452.

When the rotation of the rotation lever 452 further progresses, the pair of guide rollers 705 are handed over from the first guide surface 101R to the second guide surface 102R, and eventually the pair of guide rollers 705 come into contact with the pair of positioning portions 102S. It is fitted. The state in which the fitting is completed is the cleaning position shown in FIG. FIG. 14 is a perspective view showing a state after the cleaning unit 70 is arranged from the attachment / detachment position of FIG. 13 to the cleaning position. In this state, as shown in FIG. 2, the pressing roller 72 of the cleaning unit 70A abuts on the resist lower roller 32 from below along a straight line L connecting the center of the resist upper roller 31T and the center of the resist lower roller 32. ..

When the cleaning unit 70 reaches the cleaning position in this way, the pressing roller 72 presses the web W against the resist lower roller 32. As a result, the contact surface WA of the web W comes into contact with the surface of the resist lower roller 32, and paper dust, ink, and the like adhering to the surface of the resist lower roller 32 can be cleaned. In the posture of the cleaning unit 70 at the cleaning position shown in FIG. 2, the center of gravity (pressing roller 72) of the cleaning unit 70 is arranged directly above the unit fulcrum pin 70P, so that the posture of the cleaning unit 70 at the cleaning position is stable. And be maintained.

[Operation of cleaning unit]
FIG. 15 is a schematic view for explaining the cleaning operation of the under-resist roller 32 by the cleaning unit 70. The sheet S is passed through the resist nip portion NR formed by the resist upper roller 31 and the resist lower roller 32, and is conveyed in the direction of arrow r1. Since the transfer is in the direction of arrow r1, the upper roller 31 of the resist rotates in the direction of arrow r2 in the clockwise direction in FIG. 15, and the lower roller 32 of the resist rotates in the direction of arrow r3 in the counterclockwise direction.

The web W of the cleaning unit 70 is in contact with the roller 32 under the resist from below. As described above, when double-sided printing is applied to the sheet S, the single-sided printed sheet S is turned upside down and carried into the resist nip portion NR. At this time, ink may adhere to the surface of the roller 32 under the resist by coming into contact with the printed surface of the sheet S. Further, when the sheet S is passed through the resist nip portion NR, paper dust may fly and adhere to the surface of the resist lower roller 32. The web W wipes the foreign matter T made of the above ink, paper dust, etc. from the surface of the roller 32 under the resist.

The web W is pressed against the surface of the resist lower roller 32 by the pressing roller 72 in a state of being bridged by the pressing roller 72 arranged between the web driven roller 71 and the web driving roller 73. In other words, the contact surface WA in which the web W comes into contact with the surface of the resist lower roller 32 by sandwiching the web W in the web nip portion N formed by pressing the pressing roller 72 against the resist lower roller 32. Is formed. Since the pressing roller 72 has lower elasticity than the resist lower roller 32, the surface of the pressing roller 72 is recessed downward in the web nip portion N. By adjusting the degree of depression of the pressing roller 72 (pressure contact force with the roller 32 under resist), the nip width of the web nip portion N, that is, the width of the contact surface WA can be adjusted.

The web W is intermittently fed by the web feeding mechanism 81 (solenoid 811) in the direction of arrow r4, that is, in the direction toward the web driving roller 73. When the web W is sent in the direction of the arrow r4, the pressing roller 72 in a pressure contact state with the back surface of the web W is driven to rotate in the counterclockwise direction of the arrow r5. In this way, in the web drive roller 73, the winding direction (arrow r4) of the web W is opposite to the normal rotation direction (arrow r3) of the under-resist roller 32 that conveys the sheet S in the arrow r1 direction. As such, wind up the web W.

When foreign matter T adheres to the surface of the resist lower roller 32 at or near the resist nip portion NR, the foreign matter T moves toward the web nip portion N as the resist lower roller 32 rotates in the arrow r3 direction. Normally, since the foreign matter T cannot pass through the web nip portion N, the foreign matter T stays in the web nip portion N in a manner of being blocked upstream of the roller 32 under the resist in the rotational direction. In FIG. 15, the stagnant foreign matter T is illustrated.

In the web W, when the web W is stationary for a certain period of time during the stop period in the intermittent feed, the contact surface WA formed in the web nip portion N comes into contact with the surface of the rotating resist lower roller 32 for cleaning. .. After that, when the web W is fed in the direction of arrow r4 during the moving period in the intermittent feed, the new contact surface WA comes into contact with the surface of the roller 32 under the resist, and the cleaning is performed. Along with the feeding of the web W in the arrow r4 direction, the foreign matter T staying in the vicinity of the web nip portion N moves to the downstream side in the winding direction of the web W in a manner of being supported on the surface of the web W. To do. Therefore, the foreign matter T is taken up by the web drive roller 73 together with the used web W. Even if the foreign matter T falls near the web nip portion N or from the surface of the web W, the foreign matter T will be collected in the cleaning housing 70H.

[Effect of torque limiter during jam processing]
The operation of the cleaning unit 70 described above may be hindered. The most likely to be hindered is when a strong torque in the reverse rotation direction or the forward rotation direction acts on the pressing roller 72, typically when the sheet S is jammed.

FIG. 16 is a cross-sectional view showing a situation in which a strong torque in the reverse rotation direction acts on the pressing roller 72. FIG. 16 shows a state in which a jam of the sheet S occurs while being sandwiched between the resist nip portions NR of the resist roller pair, and the jam sheet SJ is pulled out to the downstream side in the sheet transport direction (arrow r1). ing. In this case, as the jam sheet SJ is pulled out, the resist upper roller 31 is forcibly rotated in the direction of arrow r2, and the resist lower roller 32 is forcibly rotated in the direction of arrow r3, that is, in the forward rotation direction during sheet transportation. At this time, a strong torque in the direction of arrow r51, which is the direction opposite to the original rotation direction, acts on the pressing roller 72 that is in pressure contact with the resist lower roller 32. Due to this torque, a conveying force that is sent in the direction opposite to the original feeding direction (arrow r41) acts on the web W.

FIG. 17 is a schematic view for explaining a defect when the pressing roller 72 is driven to rotate in the direction of arrow r51 by the torque from the roller under resist 32. When the pressing roller shaft 72S is not equipped with the torque limiter 72T and the pressing roller 72 rotates in the direction of arrow r51, the web W is also pulled back in the direction of arrow r41 while being conveyed to the pressing roller 72. Then, the foreign matter T of the web nip portion N, which has been blocked upstream of the resist lower roller 32 in the rotational direction, may be bitten into the web nip portion N and adhere to the surface of the resist lower roller 32 again. Reference numeral Ta in FIG. 17 indicates a reattached foreign substance. The foreign matter Ta may pass through the web nip portion N by the subsequent rotation of the roller 32 under the resist, head toward the resist nip portion NR, and be transferred to the sheet S to be passed through later.

FIG. 18 is a cross-sectional view showing a situation in which a strong torque in the forward rotation direction acts on the pressing roller 72. FIG. 18 shows that a jam of the sheet S occurs while being sandwiched between the resist nip portions NR, and the jam sheet SJ is pulled out in a direction opposite to the sheet transport direction (arrow r11). As described above, depending on the stop position of the jam sheet SJ, the pulling direction may be opposite.

In this case, as the jam sheet SJ is pulled out in the direction of arrow r11, the upper roller 31 of the resist is forced in the direction of arrow r21, which is opposite in the forward rotation direction during sheet transportation, and the lower roller 32 of the resist is forced in the direction of arrow r31. Is rotated. At this time, a strong torque in the direction of arrow r5, which is the original rotation direction, acts on the pressing roller 72 that is in pressure contact with the resist lower roller 32. Due to this torque, a conveying force sent in the original feeding direction (arrow r4) acts on the web W.

FIG. 19 is a schematic view for explaining a defect when the pressing roller 72 is forcibly driven to rotate in the direction of arrow r5 by the torque from the roller under resist 32. When the pressing roller 72 rotates in the direction of arrow r5, the web W is also forcibly extended in the direction of arrow r4 while being conveyed to the pressing roller 72. This feeding is an excessive feeding that exceeds the original amount of web winding by the web-driven roller 73. Therefore, slack Wx is generated in the web W (shown by the dotted line in FIG. 19) which is originally stretched with a constant tension between the pressing roller 72 and the web driving roller 73. When such a slack Wx occurs, the progressive feed of the web W by the web drive roller 73 is hindered by the elimination period of the slack Wx. That is, the contact surface WA of the web W, which has come into contact with the surface of the roller 32 under the resist for a normal cleaning period and is polluted, continues to come into contact with the surface. Naturally, the cleaning ability is reduced.

However, in the present embodiment, since the torque limiter 72T is arranged on the pressing roller shaft 72S, the above-mentioned problems can be prevented. The torque limiter 72T is a relatively small torque generated in the pressing roller 72 when the web W is sequentially wound from the web driven roller 71 to the web driving roller 73 through the pressing portion of the pressing roller 72 on the resist lower roller 32. 1 torque) allows the pressing roller 72 to rotate. Therefore, at the time of regular feeding and winding of the web W, the pressing roller 72 is driven to rotate in response to the movement of the web W to achieve smooth feeding and winding of the web W.

On the other hand, when a large torque (second torque) that is generated when the jam sheet SJ is forcibly pulled out and is not generated in the normal operation of the image forming apparatus 1 is generated in the pressing roller 72, the pressing roller 72 Rotation is restricted. For example, as shown in FIG. 16, when a strong torque in the reverse rotation direction acts on the pressing roller 72 via the resist lower roller 32 by pulling out the jam sheet SJ in the sheet transport direction (arrow r1), The torque limiter 72T prohibits the rotation of the pressing roller 72. Therefore, the driven reverse rotation of the pressing roller 72 in the direction of arrow r51 as shown in FIG. 17 does not occur, and the web W is not sent back in the direction of arrow r41. Therefore, the foreign matter T once wiped from the resist lower roller 32 by the web W is prevented from reattaching to the resist lower roller 32.

Further, as shown in FIG. 18, by pulling out the jam sheet SJ in the direction opposite to the sheet transport direction (arrow r11), a strong torque in the forward rotation direction acts on the pressing roller 72 via the under-resist roller 32. Also in this case, the torque limiter 72T prohibits the rotation of the pressing roller 72. Therefore, the driven forward rotation of the pressing roller 72 in the direction of arrow r5 as shown in FIG. 19 does not occur, and the web W is not excessively forwarded in the direction of arrow r4. Therefore, it is possible to prevent the slack Wx from being generated in the web W.

In the present embodiment, the drive roller shaft 73S of the web drive roller 73 is provided with a one-way clutch 73T that allows only the web W to rotate in the winding direction. By the arrangement of the one-way clutch 73T, even if the pressing roller 72 is in the driven rotation state, the disorderly reverse feed in the direction of the arrow r41 of the web W as shown in FIG. 17 is regulated. However, the general one-way clutch 73T has a play that allows a slight reverse rotation. Therefore, when a strong torque in the direction of back-feeding the web W acts on the pressing roller 72, the web W is slightly back-fed. In this case, the foreign matter T blocked in the vicinity of the web nip portion N may be bitten by the web nip portion N and then reattached to the surface of the roller 32 under the resist. However, since the driven reverse rotation of the pressing roller 72 in the arrow r51 direction is prohibited by the arrangement of the torque limiter 72T described above, even a slight reverse feed of the web W due to the play of the one-way clutch 73T can be suppressed.

Further, in the present embodiment, the driven roller shaft 71S of the web driven roller 71 is provided with a brake spring 71T that limits the rotation of the web driven roller 71 in the feeding direction. By the arrangement of the brake spring 71T, even if the pressing roller 72 is in a driven rotation state, excessive feeding of the web W in the arrow r4 direction as shown in FIG. 19 is restricted. However, when a large torque in the direction of progressively feeding the web W acts on the pressing roller 72 during jam processing or the like, the brake spring 71T alone may not be able to suppress the feeding of the web W. In this case, the web W is slackened and Wx is generated. However, due to the arrangement of the torque limiter 72T described above, the driven forward rotation of the pressing roller 72 in the arrow r5 direction is prohibited, so that the braking action is superimposed, so that the web W cannot be completely suppressed by the brake spring 71T alone. Progressive delivery can be suppressed.

[Modification example]
Although the embodiments of the present invention have been described above, the present invention is not limited to this, and for example, the following modified embodiments can be taken.

(1) In the above embodiment, an example is shown in which a brake spring 71T is attached to the web driven roller 71 and a one-way clutch 73T is attached to the web drive roller 73. Either or both of these may be omitted.

(2) In the above embodiment, an example is shown in which the transport roller cleaned by the cleaning unit 70 is the under-resist roller 32 of the resist roller unit 30. The transport roller to be cleaned may be another roller that transports the sheet S.

(3) In the above embodiment, an embodiment in which the image forming unit 50 is an inkjet method is illustrated. The image forming unit 50 may be one to which another image forming method such as a known electrophotographic method is applied.

1 Image forming device 31 Resist upper roller (upper resist roller)
32 Resist lower roller (conveyor roller, lower resist roller)
50 Image forming part 7 Cleaning device 70A Cleaning part 71 Web driven roller (feeding roller)
71S driven roller shaft (rotating shaft)
71T Brake spring (brake member)
72 Pressing roller 72S Pressing roller shaft (rotating shaft)
72T torque limiter 73 Web drive roller (winding roller)
73S drive roller shaft (rotating shaft)
73T One-way clutch W Web WA Contact surface N Web Nip part NR Resist Nip part (Nip part)

Claims (5)

A cleaning device capable of cleaning the surface of a transport roller that transports a sheet in an image forming apparatus.
The cleaning portion includes a contact surface extending along the axial direction of the transport roller, and the contact surface is in contact with the surface of the transport roller to clean the surface.
The cleaning part
A strip-shaped web forming the contact surface that contacts the transport roller, and
A pressing roller that presses the web against the transport roller,
The web includes a feeding roller for feeding the web and a winding roller for winding the web so that the portion of the web in contact with the transport roller changes.
On the rotation shaft of the pressing roller, the first torque generated in the pressing roller during feeding and winding of the web allows the pressing roller to rotate around the rotation axis, but is larger than the first torque. 2 A cleaning device provided with a torque limiter that limits the rotation of the pressing roller around the rotation axis when torque is generated on the pressing roller. In the cleaning device according to claim 1,
The take-up roller winds the web so that the take-up direction of the web is opposite to the normal rotation direction of the transport roller that conveys the sheet.
A cleaning device in which a one-way clutch that allows only rotation in the winding direction is arranged on the rotating shaft of the winding roller. In the cleaning device according to claim 2.
A cleaning device in which a brake member that limits rotation of the feeding roller in the feeding direction is arranged on the rotation shaft of the feeding roller. With the device body
A transport roller that transports the sheet and
An image forming unit that forms an image on the sheet,
The cleaning device according to any one of claims 1 to 3, which can clean the transport roller.
An image forming apparatus. In the image forming apparatus according to claim 4,
Further, an upper resist roller for transporting the sheet toward the image forming portion according to the image forming timing in the image forming portion is further provided.
The transport roller is arranged below the upper resist roller to form a nip portion through which the sheet passes with the upper resist roller, and transports the sheet toward the image forming portion in accordance with the image formation timing. Is the lower resist roller
The cleaning device is an image forming device that cleans the surface of the lower resist roller.

Images