Cleaning device and image forming apparatus

Abstract

To provide a cleaning device which can reduce the variation in the force of pressing a web against an ink jet head.SOLUTION: A cleaning device 3 comprises: a long sheet-like web 32 which wipes an ink jet head; a back-up roller 31 which holds the web 32 with the ink jet head to bring the web 32 into contact with the ink jet head; a side plate 34 which rotatably supports the back-up roller 31; and a support shaft 331 which supports the side plate 34. The side plate 34 is configured to be able to rotate relative to the support shaft 331 around the support shaft 331. The cleaning device 3 further comprises a weight 341 which is supported by the side plate 34 and generates a moment in the reverse direction to a moment with the support shaft 331 as a center by the dead weight of the back-up roller 31.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a cleaning device and an image forming apparatus. [Background technology]

[0002] Japanese Patent Laid-Open Publication No. 2015-54496 (Patent Document 1) discloses a head wiping device that wipes the nozzle surface of a liquid ejection head. In this device, both ends of the shaft of a pressure roller that presses a strip-shaped wiping web against the nozzle surface are biased by springs in a direction toward the nozzle surface. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-54496 Summary of the Invention [Problem to be solved by the invention]

[0004] When wiping off residual ink from the nozzle surface of an inkjet head using a wiping web, it is necessary to wipe with a gentle pressure so as not to damage the nozzle surface.

[0005] The above document discloses that the pressure roller is a rubber roller. If the rubber roller deforms while wiping the nozzle surface, the amount of deformation of the spring fluctuates, and the force acting on the nozzle surface fluctuates. The effect of this force fluctuation becomes significant when the nozzle surface is set to be wiped with weak pressure.

[0006] The present disclosure proposes a cleaning device that can reduce fluctuations in the force pressing the web against the inkjet head, and an image forming apparatus that includes the cleaning device. [Means for solving the problem]

[0007] The cleaning device according to the present disclosure includes a long sheet-like web for wiping the inkjet head, a backup roller for sandwiching the web between the backup roller and the inkjet head to bring the web into contact with the inkjet head, a frame member for rotatably supporting the backup roller, and a support shaft for supporting the frame member. The frame member is configured to be rotatable relative to the support shaft around the support shaft. The cleaning device further includes a weight. The weight is supported by the frame member. The weight generates a moment in the opposite direction to the moment about the support shaft due to the weight of the backup roller.

[0008] The cleaning device may further include a biasing member that biases the frame member in the direction of the moment generated by the weight.

[0009] The cleaning device may further include a drive source that transports the web in the longitudinal direction of the web, and the drive source may be supported by the frame member.

[0010] In the cleaning device, the drive source may be disposed closer to the support shaft than the backup roller.

[0011] The cleaning device may transport the web in the longitudinal direction while the web is separated from the inkjet head before wiping the inkjet head.

[0012] The cleaning device may transport the web in the longitudinal direction after wiping the inkjet head while the web is separated from the inkjet head.

[0013] The cleaning device may further include a plurality of transport rollers supported by a frame member and around which the web is wound, the plurality of transport rollers having a first roller located at the most upstream position in the transport direction of the web, the first roller being positioned directly below the support shaft so that the web contacts the inkjet head.

[0014] In the cleaning device, the plurality of transport rollers may have a final roller located at the most downstream position in the transport direction of the web, and the final roller may be arranged directly below the support shaft so that the web contacts the inkjet head.

[0015] In the above cleaning device, the pressure with which the backup roller presses the inkjet head may be set to 20 kPa or less, and the fluctuation in the load that the backup roller acts on the inkjet head due to fluctuation in the distance between the backup roller and the inkjet head may be set to 0.13 N / mm or less.

[0016] In the above cleaning device, the natural frequency of the structure supported by the frame member may be 2 Hz or more and 5 Hz or less.

[0017] The image forming apparatus according to the present disclosure includes an inkjet head that ejects ink onto an image forming body to form an image on the image forming body, and a cleaning device that cleans the inkjet head. The cleaning device includes a sheet-like web that wipes the inkjet head, a backup roller that sandwiches the web between the inkjet head and the backup roller to bring the web into contact with the inkjet head, a frame member that rotatably supports the backup roller, and a support shaft that supports the frame member. The frame member is configured to be rotatable relative to the support shaft. The cleaning device is supported by the frame member and further includes a weight that generates a moment in the opposite direction to the moment about the support shaft due to the weight of the backup roller. [Effects of the Invention]

[0018] The cleaning device of the present disclosure can reduce fluctuations in the force pressing the web against the inkjet head. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a diagram illustrating an overall configuration of an image forming apparatus. [Figure 2] 2 is a side view showing the image forming apparatus of FIG. 1 as viewed from the direction of arrow II. [Figure 3] 3 is a top view showing the image forming apparatus of FIG. 1 as viewed from the direction of arrow III. [Figure 4] FIG. 2 is a schematic diagram illustrating a configuration of a cleaning device. [Figure 5] 5A and 5B are diagrams illustrating rotation of the cleaning device around a support shaft. [Figure 6] FIG. 10 is a schematic diagram showing a partial configuration of a cleaning device according to a first modified example. [Figure 7] 10A and 10B are diagrams illustrating an operation of storing unused webs in the housing. [Figure 8] 10A and 10B are diagrams illustrating the wiping operation using the web drawn into the housing. [Figure 9] FIG. 10 is a schematic diagram showing the configuration of a cleaning device according to a second modified example. [Figure 10] FIG. 1 is a diagram showing wiping performance in Examples and Comparative Examples. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, an embodiment of an image forming apparatus according to the present disclosure will be described with reference to the drawings. In the following description, the same parts and components are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

[0021] [Configuration of image forming apparatus 1] Fig. 1 is a diagram illustrating the overall configuration of an image forming apparatus 1 equipped with a cleaning device 3 according to an embodiment. Fig. 2 is a side view of the image forming apparatus 1 shown in Fig. 1, viewed from the direction of arrow II. Fig. 3 is a top view of the image forming apparatus 1 shown in Fig. 1, viewed from the direction of arrow III.

[0022] This image forming apparatus 1 is, for example, an inkjet recording apparatus that forms an ink image on a recording medium 900 as an image forming body. Typically, the image forming apparatus 1 is a production printing machine used in fields such as commercial printing and in-house printing. Plain paper can be used as the recording medium. The plain paper may be roll paper in which a long piece of paper is wound into a roll, or may be sheets cut to a predetermined size. The recording medium may also be a resin film. The resin film may be, for example, a PET film, a PP film, or a PE film. The recording medium may also be metal, a wooden board, cloth, or the like.

[0023] 1, the image forming apparatus 1 includes a recording medium transport device 2, a cleaning device 3, a head standby unit 4, a controller 9, an inkjet head station 10, and a head moving device 11. The image forming apparatus 1 has multiple head stations 10, which will be described in detail later.

[0024] The cleaning device 3 has a backup roller 31. The head standby section 4 has a cap 41 and a waste liquid tank 42. The head standby section 4 has a plurality of caps 41, the details of which will be described later.

[0025] The recording medium conveying device 2 includes a conveying belt 20, a driving roller 21, and a driven roller 22 (FIG. 2). The recording medium 900 is conveyed by the conveying belt 20.

[0026] The head station 10 is fixed to a head moving device 11. By moving the head moving device 11, the head station 10 can move in the direction of arrow 990 (positive and negative directions of the X axis) and in the direction of arrow 991 (positive and negative directions of the Z axis).

[0027] Below the head station 10 are arranged the recording medium transport device 2, the cleaning device 3, and the head standby unit 4. When the head station 10 moves in the direction of the arrow 990, the cleaning device 3 and the head standby unit 4 are located below the head station 10.

[0028] 2, when the head moving device 11 is located directly above the recording medium transport device 2, the transport belt 20 rotates due to the rotation of the drive roller 21 and the driven roller 22 in the direction of arrow 992. As a result, the recording medium 900 in close contact with the surface of the transport belt 20 is transported in the direction of arrow 993. As the recording medium 900 passes the head station 10, ink is ejected from the head station 10 to form an image on the recording medium 900.

[0029] The head station 10 is positioned on the conveyor belt 20 during a series of print jobs. When the print job is completed, the head station 10 moves to a position where the cleaning device 3 is waiting and further to a position where the cap 41 is waiting, in response to a command from the controller 9 (FIG. 1).

[0030] 3, the image forming apparatus 1 has a plurality of head stations 10. More specifically, the head moving device 11 has a plurality of head stations 10 for each ink type or color. The head stations 10 are aligned in a row in the Y-axis direction.

[0031] Each head station 10 has a plurality of inkjet heads 101. More specifically, in this example, each head station 10 has inkjet heads 101 arranged in two rows so that the inkjet heads 101 can print across the width of the paper.

[0032] A nozzle plate (not shown) is provided on the bottom surface of the inkjet head 101. The nozzle plate has a large number of nozzles formed therein that eject ink in multiple rows. The inkjet head 101 is provided with piping (not shown) for supplying and recovering ink.

[0033] The inkjet head 101 can supply and circulate ink through the piping. Furthermore, the inkjet head 101 is provided with a device (not shown) that controls the pressure applied to the ink. This device allows the inkjet head 101 to form an ink meniscus at the nozzle outlet. During purging, the pressure is controlled to expel ink from the nozzle.

[0034] A cleaning device 3 and a cap 41 are installed at a position (position in the X-axis direction) corresponding to each head station 10. In this way, the image forming apparatus 1 has cleaning devices 3 and caps 41 equal to the number of head stations 10. In the image forming apparatus 1, maintenance of each head station 10 is performed by the cleaning device 3 and cap 41 corresponding to the head station 10.

[0035] 1, after the head station 10 executes a series of print jobs, the head moving device 11 moves the head station 10 to a position directly above the cleaning device 3. The head moving device 11 then moves downward (in the negative direction of the Z axis). This causes a cleaning member (contact wiping member) called a web in the cleaning device 3 to come into contact with a nozzle plate (not shown) on the surface of the inkjet head 101.

[0036] More specifically, relative movement occurs between the web and the head station 10 due to at least one of the movement of the head moving device 11 in the X-axis direction (in this example, the positive direction of the X-axis) and the movement of the web of the cleaning device 3. This causes the nozzle plate to be rubbed by the web. As a result, stains such as ink adhering to the surface of the nozzle plate are removed.

[0037] When the head station 10 is on standby without executing a job, the head moving device 11 moves the head station 10 to a position facing the cap 41. The cap 41 is shaped (container-like) to cover the head station 10. The cap 41 seals the nozzle plate. The reason for sealing it is to prevent bending (warping) and damage in the vicinity of the nozzles due to drying of ink near the nozzles.

[0038] There is a space between the nozzle plate covered by the cap 41 and the bottom of the cap. This space is filled with a storage liquid or the like to maintain a moist state. The storage liquid may be of any composition that prevents the ink solvent from evaporating. A waste liquid tank 42 is also provided below the cap 41 so that a purge process (ink ejection) can be performed when the nozzle plate is covered with the cap 41. A pipe (not shown) is provided on the bottom of the cap 41. The image forming apparatus 1 is also provided with a mechanism for discharging purged ink into the waste liquid tank 42.

[0039] After the purging process is completed, the head moving device 11 can move to the cleaning device 3 to clean the nozzle plate that has become soiled with the purged ink.

[0040] 1 to 3 is configured to directly form an ink image on a recording medium as an image forming body. The image forming apparatus is not limited to this configuration, and may be configured to eject ink from an inkjet head 101 onto an intermediate transfer body, form an ink image on the intermediate transfer body as an image forming body, and transfer the image from the intermediate transfer body to the recording medium.

[0041] [Configuration of cleaning device 3] Fig. 4 is a schematic diagram showing the configuration of the cleaning device 3. Fig. 4 shows a schematic cross section of the cleaning device 3 taken along line IV-IV shown in Fig. 3. As described above, the cleaning device 3 cleans the nozzle plate of the inkjet head 101 by bringing the web 32 into contact with the nozzle plate and wiping the nozzle plate.

[0042] The backup roller 31 applies pressure to the web 32 to press the web 32 against the nozzle plate. The backup roller 31 sandwiches the web 32 between itself and the inkjet head 101, bringing the web 32 into contact with the inkjet head 101. Most of the backup roller 31 is housed in a housing 33.

[0043] The backup roller 31 is made of a porous material. The material of the backup roller 31 is, for example, polypropylene. The diameter of the backup roller 31 may be 40 mm. The hardness of the outer circumferential surface of the backup roller 31 may be C7 (Asker).

[0044] The housing 33 has a side plate 34 and another side plate (not shown). The other side plate is arranged parallel to the side plate 34 and is arranged at a distance from the side plate 34 on the near side in the direction perpendicular to the plane of FIG. 4. The backup roller 31 is arranged between the side plate 34 and the other side plate. The rotation shaft of the backup roller 31 is supported by the side plate 34 and the other side plate of the housing 33. The side plate 34 corresponds to a frame member in the embodiment, which rotatably supports the backup roller 31. The side plate 34 may be formed from a flat aluminum plate. The side plate 34 may be formed by processing a 1.5 mm thick plate.

[0045] The web 32 has a long sheet shape. At the start of use, the web 32 is placed in the cleaning device 3 in a roll shape. An unused web 32 is supplied from a web supply roller 314 outside the housing 33. The web supply roller 314 around which the unused web 32 is wound is disposed below the bottom plate of the housing 33. An opening 39 that connects the inside and outside of the housing 33 is formed in the bottom plate of the housing 33. The web 32 unwound from the web supply roller 314 is introduced into the housing 33 through the opening 39.

[0046] The cleaning device 3 includes a plurality of transport rollers that support the web 32 in front of and behind the backup roller 31. The web 32 is transported while being wrapped around the plurality of transport rollers. The plurality of transport rollers includes a first roller 319, a second roller 318, a third roller 317, a fourth roller 313, a fifth roller 312, and a sixth roller 310. The rotation shaft of each transport roller is supported by a side plate 34 of the housing 33 and the other side plates described above. Each transport roller is rotatably supported by the side plate 34. Each transport roller is disposed within the housing 33.

[0047] The first roller 319, the second roller 318, the third roller 317, the fourth roller 313, the fifth roller 312, and the sixth roller 310 are arranged in this order from the upstream side to the downstream side in the conveyance direction of the web 32. The web 32 passes through the first roller 319, the second roller 318, the third roller 317, the fourth roller 313, the backup roller 31, the fifth roller 312, and the sixth roller 310 in this order. After passing through the sixth roller 310, the web 32 is discharged to the outside of the housing 33 via the opening 39. The opening 39 functions as a supply port for the web 32 into the housing 33 and also as a discharge port for the web 32 to the outside of the housing 33.

[0048] Of the multiple transport rollers supported by the housing 33, the first roller 319 is the transport roller located most upstream in the transport direction of the web 32. Of the multiple transport rollers, the first roller 319 is the transport roller around which the web 32 is first wound before wiping the inkjet head 101. The first roller 319 is the transport roller around which the web 32 is wound immediately after being introduced into the housing 33.

[0049] Of the multiple transport rollers supported by the housing 33, the sixth roller 310 is located at the most downstream position in the transport direction of the web 32 and corresponds to the final roller in the embodiment. Of the multiple transport rollers, the sixth roller 310 is the last transport roller around which the web 32 is wound after wiping the inkjet head 101. The sixth roller 310 is the transport roller around which the web 32 is wound just before being discharged outside the housing 33.

[0050] The web 32 discharged from the housing 33 moves downward by its own weight and is received by the tray 374. When an appropriate amount of the used web 32 accumulates in the tray 374, the web 32 is discarded.

[0051] When wiping the nozzle plate with the web 32, the web 32 is transported. The cleaning device 3 is equipped with a drive source 36 that pulls the web 32 while wiping the nozzle plate in order to transport the web 32. The drive source 36 is, for example, an electric motor. A driving force is transmitted from the output shaft of the drive source 36 to a drive roller 315. The drive roller 315 and an opposing roller 316 sandwich the web 32 therebetween. The outer peripheral surface of the drive roller 315 is knurled. The drive roller 315 is, for example, an aluminum roller with a diameter of 15 mm.

[0052] When the driving source 36 is driven, the driving roller 315 rotates in the counterclockwise direction in FIG. 4. At this time, the opposing roller 316 rotates in the clockwise direction in FIG. 4, following the driving roller 315. The web 32 sandwiched between the driving roller 315 and the opposing roller 316 is subjected to a circumferential force of the driving roller 315, and the web 32 is transported in the longitudinal direction.

[0053] The drive source 36 is disposed within the housing 33 and is supported by the housing 33. The rotation axes of the drive roller 315 and the opposing roller 316 are supported by the side plates 34 of the housing 33. The drive roller 315 and the opposing roller 316 are rotatably supported by the side plates 34. The drive roller 315 and the opposing roller 316 are disposed within the housing 33.

[0054] The cleaning device 3 includes a support shaft 331. The support shaft 331 supports the housing 33. The support shaft 331 rotatably supports a side plate 34 of the housing 33. The side plate 34 is configured to be rotatable relative to the support shaft 331, with the support shaft 331 as the center. A through-hole is formed in the side plate 34, penetrating the side plate 34 in the thickness direction (in FIG. 4, the direction perpendicular to the paper surface), and the support shaft 331 is disposed to pass through this through-hole. A bearing (not shown) is provided between the support shaft 331 and the side plate 34 to rotate the side plate 34 relative to the support shaft 331 without load.

[0055] The support shaft 331 is attached to a structural member (not shown) outside the housing 33. The structural member supports a structure including the housing 33, the drive source 36 arranged inside the housing 33, and each roller so that the structure is rotatable around the support shaft 331.

[0056] The driving source 36 is disposed closer to the support shaft 331 than the backup roller 31. The distance from the center of the support shaft 331 to the backup roller 31 is greater than the distance from the center of the support shaft 331 to the driving source 36. The driving source 36 is interposed between the backup roller 31 and the support shaft 331.

[0057] In an arrangement where the web 32 contacts the inkjet head 101, the first roller 319 is disposed directly below the support shaft 331. In an arrangement where the web 32 contacts the inkjet head 101, the sixth roller 310 is disposed directly below the support shaft 331. In an arrangement where the web 32 contacts the inkjet head 101, the opening 39 is disposed directly below the support shaft 331. The opening 39 is disposed directly below the first roller 319 and the sixth roller 310.

[0058] When the web 32 is disposed in contact with the inkjet head 101, in a plan view from above, at least a portion of the support shaft 331 overlaps with at least a portion of the first roller 319. At least a portion of the support shaft 331 overlaps with at least a portion of the sixth roller 310. At least a portion of the support shaft 331 overlaps with at least a portion of the opening 39. At least a portion of the first roller 319 overlaps with at least a portion of the opening 39. At least a portion of the sixth roller 310 overlaps with at least a portion of the opening 39.

[0059] The cleaning device 3 further includes a weight 341. The weight 341 is disposed outside the housing 33. The weight 341 is supported by the side plate 34. The weight 341 is supported by the housing 33 and is rotatable integrally with the housing 33 around a support shaft 331. The weight 341 is disposed on the opposite side of the support shaft 331 from the backup roller 31. The weight 341 may be configured so that its position can be changed. Specifically, the weight 341 may be configured so that it can move back and forth so that the distance between the housing 33 and the weight 341 can be changed.

[0060] The weight 341 generates a moment in the opposite direction to the moment about the support shaft 331 due to the weight of the backup roller 31. Specifically, the backup roller 31, the drive source 36, and each roller act on the moment in a direction that causes the housing 33 to rotate counterclockwise in FIG. 4. The weight 341 acts on the moment in a direction that causes the housing 33 to rotate clockwise in FIG. 4. The weight 341 acts on the backup roller 31 and the web 32 wound around the backup roller 31 to move closer to the inkjet head 101. In the arrangement shown in FIG. 4, the moment due to the weight 341 causes the backup roller 31 to receive an upward force.

[0061] The cleaning device 3 further includes a spring 342. The lower end of the spring 342 is fixed to a horizontal base plate 340 outside the housing 33, and the position remains unchanged even when the housing 33 rotates around the support shaft 331. The upper end of the spring 342 is attached to a weight 341. The spring 342 is stretched longer than its natural length. The restoring force of the spring 342 biases the housing 33 in the same direction as the moment generated by the weight 341. The spring 342 corresponds to the biasing member of the embodiment. In the arrangement shown in FIG. 4, the spring 342 biases the housing 33 including the backup roller 31 vertically upward.

[0062] Fig. 5 is a diagram illustrating the rotation of the cleaning device 3 around the support shaft 331. In Fig. 5, the broken line indicates the arrangement of the cleaning device 3 shown in Fig. 4. The solid line in Fig. 5 indicates the arrangement of the cleaning device 3 after it has rotated and moved around the support shaft 331, as indicated by the arrow in Fig. 5.

[0063] The driving source 36, the backup roller 31, and the plurality of transport rollers act as a counterclockwise moment around the support shaft 331 in Fig. 5. The weight 341 and the spring 342 act as a clockwise moment around the support shaft 331 in Fig. 5. By appropriately adjusting the weight and position of the weight 341 and the specifications and position of the spring 342, the moment from the weight 341 and the spring 342 can apply an upward force, i.e., a force toward the inkjet head 101, to the backup roller 31 and the web 32 wound around the backup roller 31.

[0064] The pressure that the backup roller 31 applies to the inkjet head 101 is generated by a weight 341 and a spring 342. The upward load (pressure when the area is taken into consideration) generated by the weight 341 has the characteristic of barely fluctuating depending on the amount of pressure applied to the backup roller 31. The load generated by the spring 342 fluctuates depending on the amount of pressure applied to the backup roller 31. Using both the weight 341 and the spring 342 makes it possible to use a spring 342 with a small spring constant.

[0065] [Transportation of the web 32 outside the wiping operation period] Fig. 6 is a schematic diagram showing a partial configuration of a cleaning device 3 according to a first modified example. The cleaning device 3 according to the first modified example shown in Fig. 6 differs from the configuration shown in Fig. 4 in that a long hole 38 is formed in the side plate 34, penetrating the side plate 34 in the thickness direction, and a rod-shaped pulling member 351 is provided which penetrates the long hole 38.

[0066] The tensioning material 351 is disposed midway between the two transport rollers in the transport direction of the web 32. The web 32 is wound around the tensioning material 351. The two transport rollers before and after the tensioning material 351 in the transport direction of the web 32 are disposed farther from the wall surface of the housing 33 than the web 32. The tensioning material 351 is disposed closer to the wall surface of the housing 33 than the web 32. The transport rollers are disposed inside the web 32 wound around the multiple transport rollers and backup roller 31, while the tensioning material 351 is disposed outside the web 32. In the arrangement shown in FIG. 6, the tensioning material 351 is disposed at one end of the elongated hole 38 (the left end in the figure). The tensioning material 351 is disposed above the second roller 318 and below the third roller 317.

[0067] In a structure in which the housing 33 rotates around the support shaft 331, it is necessary to supply unused web 32 to the backup roller 31 while the web 32 is being transported and wiping the inkjet head 101. However, when unused web 32 is introduced from outside the housing 33, the housing 33 pulls up the unused web 32. At this time, the tension of the web 32 causes a moment to act on the housing 33 in a counterclockwise rotation direction around the support shaft 331. The force that fluctuates the amount of extension of the spring 342 causes the load generated by the spring 342 to fluctuate, which may result in fluctuations in the pressure from the backup roller 31 to the inkjet head 101.

[0068] For this reason, in the example shown in FIG. 6 and the subsequent FIGS. 7 and 8, unused web 32 is stored in housing 33 during periods when the inkjet head 101 is not being wiped.

[0069] FIG. 7 is a diagram illustrating the operation of storing unused web 32 in housing 33. Housing 33 and pressing member 352 are configured to move relative to each other. As pressing member 352 moves to the right in FIG. 7, pressing member 352 moves pulling member 351 from left to right in the figure. As pulling member 351 presses web 32 to the right in FIG. 7, web 32 is pulled into housing 33 while wrapped around pulling member 351. As a result, unused web 32 is stored in housing 33.

[0070] The operation of drawing the web 32 into the housing 33 is performed while the inkjet head 101 is not being wiped. While the web 32 is being drawn into the housing 33, the drive source 36 is stopped and the drive roller 315 is stopped rotating. While the web 32 is being drawn into the housing 33, the web 32 does not move relative to the backup roller 31. While the web 32 is separated from the inkjet head 101, an operation of conveying the unused web 32, which has not yet wiped the inkjet head 101, in the longitudinal direction and drawing the web 32 into the housing 33 is performed.

[0071] When the pulling member 351 moves to the other end of the elongated hole 38 (the right end in the figure) and finishes pulling the web 32 into the housing 33, the pressing member 352 then moves in the opposite direction (to the left in FIG. 7) and separates from the pulling member 351. The pressing member 352 moves to the left side of the housing 33 (see also FIG. 8).

[0072] 6 and 7, the pressing member 352 moves relative to the stationary housing 33, causing the housing 33 and the pressing member 352 to move relative to each other. However, the housing 33 may also move relative to the stationary pressing member 352, causing the pulling member 351 to move and pull the web 32 into the housing 33. In this case, the web supply roller 314 outside the housing 33 also moves together with the housing 33. Both the pressing member 352 and the housing 33 may move.

[0073] FIG. 8 is a diagram illustrating the wiping operation using the web 32 drawn into the housing 33. During the wiping operation of the inkjet head 101, the unused web 32 drawn into the housing 33 is pulled by the driving force generated by the driving source 36 and supplied to the backup roller 31 for use in wiping. The tensioning member 351 gradually moves to the left in the figure along the elongated hole 38 during wiping. The tensioning member 351 applies tension to the web 32, allowing for a stable supply of the web 32. During the wiping operation, the web 32 is not unwound from the web supply roller 314, and the web 32 does not move relative to the first roller 319 and the second roller 318.

[0074] This eliminates the need to draw unused web 32 into housing 33 during wiping operation. It is possible to prevent unnecessary moment from being generated in housing 33 due to the influence of tension of web 32. The amount of extension of spring 342 can be kept constant, and fluctuations in the load generated by spring 342 can be suppressed, so fluctuations in the pressure from backup roller 31 to inkjet head 101 can be prevented.

[0075] Fig. 9 is a schematic diagram showing the configuration of a cleaning device 3 according to a second modified example. In addition to the configuration shown in Fig. 4, the cleaning device 3 according to the second modified example shown in Fig. 9 includes a web take-up roller 371, a seventh roller 372 included in the transport rollers, a drive source 373, and a drive roller 376. The web take-up roller 371, the seventh roller 372, the drive source 373, and the drive roller 376 are disposed outside the housing 33, more specifically, below the housing 33. The seventh roller 372 is disposed immediately above the tray 374 also shown in Fig. 4.

[0076] After wiping the inkjet head 101, the web 32 passes through the opening 39 and is discharged from the housing 33, and then passes through the seventh roller 372 and is taken up by the web take-up roller 371. When the drive source 373 is driven, a driving force is transmitted to the drive roller 376, causing the drive roller 376 to rotate counterclockwise in the figure. When the web take-up roller 371 rotates clockwise in the figure, the web 32 is taken up by the web take-up roller 371.

[0077] During the wiping operation of the inkjet head 101, the web 32 is transported in the longitudinal direction from the backup roller 31 to the fifth roller 312 by the driving force generated by the driving source 36 being transmitted via the driving roller 315. The web 32 is wound around the sixth roller 310 and moves downward by gravity.

[0078] If the speed at which the web 32 is wound by the web winding roller 371 is faster than the speed at which the web 32 is transported by the drive source 36, a force is applied to the housing 33 through the web 32. At this time, a moment acts on the housing 33 in a direction that rotates it counterclockwise around the support shaft 331. The force that varies the amount of extension of the spring 342 causes the load generated by the spring 342 to vary, which may result in a fluctuation in the pressure from the backup roller 31 to the inkjet head 101.

[0079] To avoid this, the speed at which the web 32 is taken up by the web take-up roller 371 during the wiping operation is set to be slower than the speed at which the web 32 is conveyed by the drive source 36. Typically, the rotation speed of the web take-up roller 371 during the wiping operation is set to zero. During the wiping operation, the drive source 373 is stopped to stop the take-up of the web 32 onto the web take-up roller 371.

[0080] By doing so, only gravity acts on the web 32 after wiping during the wiping operation. Since the web 32 only moves downward under its own weight, it is possible to prevent the web take-up roller 371 from pulling on the housing 33 through the web 32 during the wiping operation. The amount of extension of the spring 342 can be kept constant, and fluctuations in the load generated by the spring 342 can be suppressed, so it is possible to prevent fluctuations in the pressure from the backup roller 31 to the inkjet head 101.

[0081] In this case, the web 32 will slacken and remain downstream of the drive roller 315 in the conveying direction. The slackened web 32 will accumulate in a slackening position 375 in the housing 33, on the tray 374, and the like. The operation of winding up the slackened web 32 onto the web take-up roller 371 is performed while the inkjet head 101 is not being wiped. While the inkjet head 101 is not being wiped, the web take-up roller 371 is rotated to discharge the web 32 from the housing 33 and wind it up onto the web take-up roller 371. While the web 32 is separated from the inkjet head 101, the used web 32 after wiping the inkjet head 101 is transported in the longitudinal direction and discharged out of the housing 33.

[0082] [Action and effect] Although some of the description overlaps with the above description, the characteristic configuration and effects of the cleaning device 3 of this embodiment can be summarized as follows.

[0083] As shown in Fig. 4, cleaning device 3 includes a side plate 34 of housing 33 that rotatably supports backup roller 31, and a support shaft 331 that supports housing 33. As shown in Fig. 5, side plate 34 is configured to be rotatable relative to support shaft 331. As shown in Fig. 4, cleaning device 3 further includes weight 341. Weight 341 is supported by housing 33. Weight 341 generates a moment in the opposite direction to the moment about support shaft 331 due to the weight of backup roller 31.

[0084] The weight of the backup roller 31 is offset by the weight 341, and a pressing force in the direction toward the inkjet head 101 is applied to the backup roller 31 and the web 32 wound around the backup roller 31. The load of this weight 341 hardly fluctuates even if the amount of pressure from the backup roller 31 to the inkjet head 101 fluctuates due to deformation of the backup roller 31 during the wiping operation. By using the weight 341 to generate the force that the backup roller 31 applies to the inkjet head 101, it is possible to reduce fluctuations in the force pressing the web 32 against the inkjet head 101.

[0085] As shown in FIG. 4, the cleaning device 3 may further include a spring 342 that biases the housing 33 in the direction of the moment generated by the weight 341. To apply the required load to the inkjet head 101, both the weight 341 and the spring 342 are used. To reduce load fluctuations due to variations in the amount of pressure from the backup roller 31 to the inkjet head 101, it is preferable to use a spring 342 with a small spring constant. Because the weight 341 offsets the weight including the backup roller 31, even if a spring 342 with a small spring constant is used, the amount of deformation of the spring 342 required to generate the required elastic force can be reduced, allowing a stable load to be applied to the inkjet head 101. This eliminates the need to use a long spring 342, simplifying the design.

[0086] As shown in FIG. 4, the drive source 36 that transports the web 32 in the longitudinal direction of the web 32 may be supported by the housing 33. Both the drive source 36 and the backup roller 31 are fixed to the housing 33 and form an integrated structure. As a result, even if the drive source 36 pulls and transports the web 32 during the wiping operation, the tension of the web 32 does not affect the moment generated by the weight 341 and the spring 342. In other words, even if the tension of the web 32 fluctuates, the pressure with which the backup roller 31 presses the inkjet head 101 does not fluctuate. Therefore, fluctuations in the force pressing the web 32 against the inkjet head 101 can be effectively reduced.

[0087] As shown in FIG. 4, the driving source 36 may be disposed closer to the support shaft 331 than the backup roller 31.

[0088] The weight of the housing 33, the rollers and drive sources fixedly arranged within the housing 33, and the weight 341 create a moment of inertia with respect to the support shaft 331. A small moment of inertia is preferable. A large moment of inertia reduces the natural frequency of the structure centered on the support shaft 331. During the wiping operation, fluctuations in friction and unevenness on the surface of the inkjet head 101 may cause the backup roller 31 to bounce away from the inkjet head 101. If the natural frequency is small, it takes time for the backup roller 31 to return to its original position and contact the inkjet head 101 again after bouncing. This increases the time during which no pressure is applied to the inkjet head 101, which may result in residual ink being left on the nozzle surface.

[0089] The component that contributes most to the moment of inertia is the drive source 36. This is because the drive source 36 has the largest weight. Therefore, it is desirable to install the drive source 36 near the support shaft 331. By placing the drive source 36 closer to the support shaft 331 than the backup roller 31, the moment of inertia can be reliably reduced. In addition, the moment of inertia of each roller that is placed farther away from the support shaft 331 can also be further reduced by making the rotating shaft hollow or using resin to minimize weight.

[0090] The natural frequency of the structure supported by the housing 33, including the backup roller 31, the drive source 36, and the weight 341 shown in FIG. 4, may be 2 Hz or more and 5 Hz or less. By setting the natural frequency in this manner, even if splashing occurs during the wiping operation, the backup roller 31 will come into contact with the inkjet head 101 again within an allowable time. This makes it possible to prevent unwiped areas from remaining on the inkjet head 101, and allows the cleaning device 3 to reliably clean the inkjet head 101.

[0091] As shown in FIGS. 6 and 7, the cleaning device 3 may transport the web 32 in the longitudinal direction while the web 32 is spaced apart from the inkjet head 101 before wiping the inkjet head 101.

[0092] To transport the web 32 before wiping the inkjet head 101, the drive source 36 generates a driving force, and the drive roller 315 and the opposing roller 316 pull the web 32. At this time, tension is applied to the web 32. This tension acts on the backup roller 31. The tension of the web 32 acts on the backup roller 31 in a direction that moves the backup roller 31 away from the inkjet head 101. The pressing force of the spring 342 acting on the backup roller 31 in the direction toward the inkjet head 101 is offset by the tension of the web 32. If the tension of the web 32 fluctuates, the force pressing the web 32 against the inkjet head 101 also fluctuates. If the spring constant of the spring 342 is small, the effect of the tension of the web 32 becomes greater, which becomes a factor in load fluctuations.

[0093] By drawing unused web 32 into housing 33 while inkjet head 101 is not being wiped, and transporting the web 32 drawn into housing 33 during the wiping operation, it is no longer necessary to draw unused web 32 into housing 33 during the wiping operation. This makes it possible to prevent unnecessary moment from being generated in housing 33 due to the influence of the tension of web 32. Since it is possible to prevent the supply of web 32 into housing 33 from becoming a factor of fluctuation, it is possible to more reliably reduce fluctuations in the force pressing web 32 against inkjet head 101.

[0094] As shown in FIG. 9, the cleaning device 3 may transport the web 32 in the longitudinal direction after wiping the inkjet head 101 while the web 32 is separated from the inkjet head 101.

[0095] To wind up the web 32 onto the web take-up roller 371 after wiping the inkjet head 101, the drive source 373 generates a driving force to pull the web 32. At this time, tension is applied to the web 32. By retaining the used web 32 rather than transporting it during the wiping operation and transporting the used web 32 while the inkjet head 101 is not being wiped, it is possible to prevent unnecessary moment from being generated in the housing 33 due to the influence of the tension of the web 32 during the wiping operation. Since it is possible to prevent the discharge of the web 32 out of the housing 33 from becoming a fluctuation factor, it is possible to more reliably reduce fluctuations in the force pressing the web 32 against the inkjet head 101.

[0096] As shown in FIG. 4 , among the multiple transport rollers, the first roller 319, which is located at the most upstream position in the transport direction of the web 32, may be disposed immediately below the support shaft 331 so that the web 32 contacts the inkjet head 101. The web 32 between the web supply roller 314 and the first roller 319, which is located upstream of the first roller 319 in the transport direction of the web 32, has a certain amount of tension and weight. The tension and weight of the web 32 generate a moment in the housing 33, which acts as a disturbance to the pressure with which the backup roller 31 presses the inkjet head 101. The influence of tension is particularly significant. By disposing the first roller 319 immediately below the support shaft 331, the moment generated by the tension and weight of the web 32 can be minimized, thereby more reliably reducing fluctuations in the force pressing the web 32 against the inkjet head 101.

[0097] As shown in FIG. 4 , among the multiple transport rollers, the sixth roller 310, which is located furthest downstream in the transport direction of the web 32, may be disposed immediately below the support shaft 331 so that the web 32 contacts the inkjet head 101. The web 32 downstream of the sixth roller 310 in the transport direction of the web 32 has a certain amount of tension and weight. The tension and weight of the web 32 generate a moment in the housing 33, which acts as a disturbance to the pressure with which the backup roller 31 presses the inkjet head 101. The influence of tension is particularly large. By disposing the sixth roller 310 immediately below the support shaft 331, the moment generated by the tension and weight of the web 32 can be minimized, thereby more reliably reducing fluctuations in the force pressing the web 32 against the inkjet head 101.

[0098] In the embodiment described above, both weight 341 and spring 342 are disposed on the same side of support shaft 331. Specifically, both weight 341 and spring 342 are disposed on the right side of support shaft 331 in the drawing. Spring 342 applies a moment to backup roller 31 and housing 33 in a state where it is stretched beyond its natural length. However, this example is not limiting, and spring 342 may bias backup roller 31 and housing 33 in any direction in the direction of the moment generated by weight 341.

[0099] For example, weight 341 and spring 342 may be disposed on opposite sides of support shaft 331. Specifically, weight 341 may be disposed on the right side of support shaft 331 in the drawing, and spring 342 may be disposed on the left side of support shaft 331 in the drawing, with spring 342 biasing backup roller 31 and housing 33 in a state where it is compressed from its natural length. Spring 342 may have an upper end attached to the bottom plate of housing 33 and a lower end attached to a horizontal base plate below housing 33.

[0100] In the embodiment, the driving source 36 and the rollers including the backup roller 31 are disposed inside the housing 33, but the housing 33 does not necessarily have to be provided. Any frame member corresponding to the side plate 34 may be configured to support the driving source 36 and the rotation shafts of the rollers, and further support the weight 341. For example, the driving source 36 and the rollers may be supported on a flat frame member. [Example]

[0101] An example will be described below. The set value of the pressure with which backup roller 31 presses inkjet head 101 is defined as set pressure P. The load applied to inkjet head 101 at the position of backup roller 31 is defined as required load F. In order to obtain an arbitrary set pressure in the range of 0.25 to 20 kPa, the presence or absence of weight 341 and spring 342, the position of weight 341, the specifications of spring 342, and the fixed position of spring 342 to housing 33 were changed, and the change in load relative to the change in the distance between backup roller 31 and inkjet head 101 was calculated.

[0102] Fig. 10 is a diagram showing the wiping performance of the cleaning devices of the example and the comparative example. As explained with reference to Fig. 3, two rows of inkjet heads 101 are arranged parallel to each other in the head station 10, and the cleaning device 3 wipes the nozzle faces of the inkjet heads 101 over a width of 40 mm during wiping.

[0103] The contact length (nip length) between the web 32 biased by the backup roller 31 and the inkjet head 101 changes according to the set pressure P. Specifically, the nip length is 8 mm when the set pressure P is 10 to 25 kPa, 7 mm when the set pressure P is 5 kPa, 5 mm when the set pressure P is 2 kPa, 4 mm when the set pressure P is 1 kPa, 3 mm when the set pressure P is 0.5 kPa, and 2 mm when the set pressure P is 0.25 kPa. The contact area between the web 32 biased by the backup roller 31 and the inkjet head 101 is the product of the width (40 mm) and the nip length. The required load F is calculated from the product of the set pressure P and the contact area.

[0104] The fulcrum length L1 is the distance from the support shaft 331 to the center position of the backup roller 31. The fulcrum length L2 is the distance from the fixed position of the spring 342 to the housing 33 to the support shaft 331, and the fulcrum length L2 can be adjusted arbitrarily by adjusting the fixed position of the spring 342.

[0105] The spring length lo is the natural length of the spring 342 when it is not stretched or contracted. The set length ls indicates the spring length required to apply the set pressure P. The usage limit of the spring 342 indicates the maximum length to which the spring 342 can be stretched.

[0106] In Comparative Examples 1 to 11, the required set pressure P was generated only by the spring 342. In Comparative Example 12 and Examples 1 to 7, the spring 342 and the weight 341 were used together, and the rotation moment due to the weight of the cleaning device 3 was set to be canceled by the weight 341. In Example 8, the spring 342 was not used, and the backup roller 31 was set to be pressed against the inkjet head 101 only by the moment due to the weight 341.

[0107] The mass of the structure including the housing 33 and the components supported by the housing 33, including the backup roller 31 and the drive source 36, is set to 270 g, and the moment of inertia of the structure is set to 0.0022 kg m 2 By doing so, the natural frequency of the structure was set in the range of 2 Hz to 5 Hz.

[0108] <When pressure is set using only spring 342> As shown in FIG. 10, in Comparative Example 1, spring 342 was selected to set the set pressure P to 20 kPa, and it can be seen that with this setting, a load fluctuation of approximately 0.61 N occurs with a 1 mm variation in the distance between backup roller 31 and inkjet head 101. This load fluctuation corresponds to approximately 9.6% of the required load F. In other words, a 1 mm variation in the distance between backup roller 31 and inkjet head 101 results in a fluctuation of approximately 9.6% in the pressure applied to inkjet head 101.

[0109] In Comparative Example 4, where the set pressure P was made even smaller, the fluctuation was approximately 46% of the set pressure P. In Comparative Examples 5 to 7, where the set pressure was made even smaller, the pressure fluctuation was greater than the set pressure, resulting in a failure in the design and making the products unacceptable.

[0110] Comparative Examples 8 to 11 show the results when a spring 342 with a smaller spring constant was selected at the same set pressure P compared to Comparative Examples 1 to 4. In Comparative Examples 8 and 9, the load fluctuation was reduced due to the effect of reducing the spring constant, but in Comparative Examples 10 and 11, the set length ls of the spring 342 was longer than the use limit and was unusable. It can be seen that if the spring constant is reduced to suppress the load fluctuation, the amount of extension of the spring 342 that supports the weight of the cleaning device 3 becomes an issue. In particular, it can be seen that the lower the set pressure P, the more difficult the design becomes.

[0111] <Load fluctuation and wiping performance> The influence of load fluctuations on the ink wiping performance in the examples and comparative examples was examined by the following method.

[0112] A backup roller 31 with a central axis eccentric by 0.7 mm was prepared and attached to the cleaning device 3. The inkjet head 101 and cleaning device 3 were moved relative to each other while the web 32 wiped the inkjet head 101. Because the central axis is eccentric, the backup roller 31 moves slightly up and down by about 1 mm per rotation. The amount of extension of the spring 342 fluctuates as the backup roller 31 moves, causing load fluctuations.

[0113] The backup roller 31 was set to rotate once while the cleaning device 3 moved in the longitudinal direction of the inkjet head 101. The backup roller 31 was set to stop at the maximum eccentric position, i.e., the position where the distance from the central axis of the backup roller 31 to the outer periphery is greatest, directly above the central axis until it came into contact with the inkjet head 101, and then start rotating at the same time as it started wiping the inkjet head 101. With this setting, the central portion of the inkjet head 101 in the longitudinal direction is always wiped with the lowest pressure.

[0114] Ink droplets with a diameter of about 1 mm were formed on the nozzle surface of the inkjet head 101 at intervals of 5 mm in the longitudinal direction of the inkjet head 101 (the wiping direction by the cleaning device 3), and the ink was forcibly fixed by drying.

[0115] Following the procedure described above, the nozzle surface of the inkjet head 101 was wiped with the web 32 a maximum of 10 times. Then, the central portion of the inkjet head 101 in the longitudinal direction, which was wiped with a relatively low pressure, and the edges of the inkjet head 101 in the longitudinal direction, which was wiped with a relatively high pressure, were checked for unevenness in ink removal. The difference in ink droplet removal between the central portion and edges of the inkjet head 101 was visually evaluated. In Figure 10, if unevenness was observed, the result was judged as NG, and if no unevenness was observed, the result was judged as OK. Note that wiping was stopped when unevenness was observed during the 10 wipes.

[0116] 10, in Comparative Examples 1 to 4, the ink wiping performance was low and unevenness was observed in the center of the inkjet head 101. In Comparative Examples 8 and 9, a spring 342 with a small spring constant was selected, but unevenness was also observed. In Comparative Example 12, weight 341 and spring 342 were used in combination, and weight 341 was set to cancel out the moment due to the weight of cleaning device 3, but because the set pressure P was large and the load fluctuation was also large, unevenness was also observed.

[0117] It can be seen that in Examples 1 to 7, the use of weight 341 allowed the use of spring 342 with a smaller spring constant compared to Comparative Examples 1 to 7, at the same set pressure P. It can be seen that even with a small spring constant, the amount of extension of spring 342 can be kept small, making design easier. There were no problems with uneven ink removal in Examples 1 to 7, and ink was removed uniformly from the center and edges of inkjet head 101. Comparing Comparative Example 12 with Examples 1 to 7, it was shown that as long as the set pressure was set to 20 kPa or less and the load fluctuation was set to 0.13 N / mm or less, fluctuations in the distance between backup roller 31 and inkjet head 101 had little effect on wiping performance, and good wiping performance could be obtained.

[0118] In Example 8, the backup roller 31 was pressed against the inkjet head 101 only by the weight 341 without using the spring 342, but even in this case, no unevenness was observed and the ink was removed uniformly from the center and edges of the inkjet head 101. This demonstrates that even if the cleaning device 3 does not necessarily have to be equipped with the spring 342, sufficient wiping performance can be obtained by selecting a weight 341 with an appropriate weight and adjusting the position of the weight 341 appropriately.

[0119] In Example 8, a force is applied to press the web 32 against the inkjet head 101 without using the spring 342, which is desirable because it can reduce the load fluctuation to almost zero and reduce the load fluctuation relative to the amount of pressing, as shown in Figure 10. On the other hand, in Examples 1 to 7, which use both the weight 341 and the spring 342, if a bounce occurs during the wiping operation, the vibration can be damped in a short time and the backup roller 31 can be quickly brought into contact with the inkjet head 101 again, which is desirable in terms of improving followability.

[0120] Although the embodiments and examples have been described above, configurations described in the embodiments that can be combined with each other may be appropriately combined. Furthermore, the embodiments disclosed herein are illustrative in all respects and should not be considered limiting. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0121] 1 image forming apparatus, 3 cleaning device, 10 head station, 11 head moving device, 31 backup roller, 32 web, 33 housing, 34 side plate, 36, 373 drive source, 38 elongated hole, 39 opening, 101 inkjet head, 310 sixth roller, 312 fifth roller, 313 fourth roller, 314 web supply roller, 315, 376 drive roller, 316 opposing roller, 317 third roller, 318 second roller, 319 first roller, 331 support shaft, 340 horizontal base plate, 341 weight, 342 spring, 351 tension member, 352 pressing member, 371 web winding roller, 372 seventh roller, 374 tray, 375 retention point, 900 recording medium.

Claims

1. a long sheet-like web for wiping the inkjet head; a backup roller for sandwiching the web between the backup roller and the inkjet head to bring the web into contact with the inkjet head; a frame member that rotatably supports the backup roller; a support shaft for supporting the frame member, the frame member is configured to be rotatable relative to the support shaft around the support shaft, The cleaning device further comprises a weight supported by the frame member for generating a moment in a direction opposite to a moment about the support shaft due to the weight of the backup roller.

2. 2. The cleaning device according to claim 1, further comprising a biasing member that biases the frame member in the direction of the moment generated by the weight.

3. a drive source that transports the web in the longitudinal direction of the web; 3. The cleaning device according to claim 1, wherein the drive source is supported by the frame member.

4. The cleaning device according to claim 3 , wherein the drive source is disposed closer to the support shaft than the backup roller.

5. The cleaning device according to claim 1 , wherein the web is transported in the longitudinal direction of the web before wiping the inkjet head while the web is separated from the inkjet head.

6. The cleaning device according to claim 3 , wherein the web, after wiping the inkjet head, is transported in the longitudinal direction of the web while the web is spaced apart from the inkjet head.

7. The web further includes a plurality of transport rollers supported by the frame member and around which the web is wound, the plurality of transport rollers includes a first roller located at the most upstream position in a transport direction of the web, The cleaning device according to claim 1 , wherein the first roller is disposed immediately below the support shaft with the web in contact with the inkjet head.

8. The web further includes a plurality of transport rollers supported by the frame member and around which the web is wound, the plurality of transport rollers includes a final roller located at the most downstream side in the transport direction of the web, The cleaning device according to claim 1 , wherein the final roller is disposed immediately below the support shaft with the web in contact with the inkjet head.

9. a pressure with which the backup roller presses the inkjet head is set to 20 kPa or less; 9. The cleaning device according to claim 1, wherein a change in the load applied by the backup roller to the inkjet head due to a change in the distance between the backup roller and the inkjet head is set to 0.13 N / mm or less.

10. 10. The cleaning device according to claim 1, wherein a natural frequency of a structure supported by the frame member is 2 Hz or more and 5 Hz or less.

11. an inkjet head that ejects ink onto an image forming body to form an image on the image forming body; a cleaning device for cleaning the inkjet head, The cleaning device a sheet-like web for wiping the inkjet head; a backup roller for sandwiching the web between the backup roller and the inkjet head to bring the web into contact with the inkjet head; a frame member that rotatably supports the backup roller; a support shaft for supporting the frame member, the frame member is configured to be rotatable relative to the support shaft around the support shaft, a weight supported by the frame member for generating a moment in a direction opposite to a moment about the support shaft due to the weight of the backup roller, Image forming device.

Images