Intermediate transfer unit and image forming apparatus equipped with the same

Abstract

To provide an intermediate transfer unit that can accurately regulate the positional relationship of a cleaning member cleaning a roller surface and a receiving member with respect to a roller, and an image forming apparatus including the same.SOLUTION: An intermediate transfer unit comprises: an intermediate transfer belt; a driving roller; a tension roller; a primary transfer member; a belt cleaning device; and a roller cleaning mechanism. The driving roller is arranged on one end side in the direction of travel of the intermediate transfer belt and applies a rotational driving force to the intermediate transfer belt. The tension roller is arranged on the other end side in the direction of travel of the intermediate transfer belt and applies a predetermined tension to the intermediate transfer belt. The roller cleaning mechanism is arranged inside the intermediate transfer belt and opposite to the tension roller, and has a cleaning member that removes a foreign substance attached to the tension roller, a receiving member that receives the foreign substance removed by the cleaning member, and a support frame that supports the cleaning member and the receiving member. The support frame is supported by bearing parts of the tension roller.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an intermediate transfer unit that is installed in an electrophotographic image forming apparatus such as a copier, printer, or facsimile, and that performs primary transfer of a toner image on an image carrier onto an intermediate transfer belt, and to an image forming apparatus equipped with the same. [Background technology]

[0002] Conventionally, there has been known an intermediate transfer type image forming device that includes an endless intermediate transfer belt that rotates in a predetermined direction and a number of image forming units arranged along the intermediate transfer belt, in which each image forming unit sequentially superimposes a toner image of each color onto the intermediate transfer belt as a primary transfer, and then performs a secondary transfer onto a recording medium such as transfer paper.

[0003] In an intermediate transfer type image forming apparatus, the intermediate transfer belt arranged opposite to the photoreceptor is generally tensioned by a plurality of rollers. In such an image forming apparatus, scattered toner is likely to be generated during development and transfer, and paper dust and the like is likely to be generated during secondary transfer to transfer paper and during peeling of the transfer paper from the intermediate transfer belt. These scattered toners and paper dusts not only adhere to the surface of the intermediate transfer belt, but also move around to the back side of the intermediate transfer belt and adhere to the tension roller that stretches the intermediate transfer belt. When the scattered toners and paper dusts adhere to the tension roller, they are compressed and solidified by the tension force between the intermediate transfer belt and the tension roller. When the intermediate transfer belt comes into contact with the tension roller, concave scratches are generated on the back side of the intermediate transfer belt, and convex scratches and thickness unevenness are generated on the belt surface, which may cause transfer failure.

[0004] In particular, when a tension roller that is not provided with an elastic layer such as a urethane coat or a rubber layer is used, the tension roller is made of a metal material, etc., and therefore is less deformed in the radial direction. Therefore, if a foreign object is present between the surface of the tension roller and the back side of the intermediate transfer belt, the intermediate transfer belt is forced to deform, and the occurrence of scratches on the intermediate transfer belt as described above becomes prominent.

[0005] Therefore, a method for cleaning the surface of a tension roller that stretches the intermediate transfer belt has been proposed, and Patent Document 1 discloses an image forming device that includes a plurality of roller members that stretch a belt member so as to be drivable, a cleaning member that contacts at least one of the roller members to clean the roller members, and an elastic member that presses the cleaning member toward the roller members. Patent Document 2 discloses a transfer device that has a plate-shaped cleaning member that contacts the surface of a drive roller that drives the intermediate transfer belt and cleans the drive roller surface. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2007-304502 A [Patent Document 2] JP 2013-76935 A Summary of the Invention [Problem to be solved by the invention]

[0007] In the configuration of Patent Document 1, the attachment end of the cleaning member (felt and mylar) is supported by a bracket different from the rotation fulcrum of the roller. Therefore, the positional relationship between the cleaning member and the roller changes due to changes in the diameter of the roller member caused by environmental temperature or deterioration over time, and it may not be possible to sufficiently clean the surface of the roller.

[0008] In addition, the configuration of Patent Document 2 includes a support member having a positioning portion that engages with the bearing member to position it, and a support portion that supports the cleaning member, but the cleaning member is fixed in a counter direction (diagonally upward) to the rotation direction of the drive roller (from top to bottom). Therefore, there is no need to provide a receiving member to receive the toner scraped off the roller surface by the cleaning member, and there is no description of the positioning of the receiving member.

[0009] In view of the above problems, the present invention aims to provide an intermediate transfer unit and an image forming apparatus equipped with the same, which can precisely define the positional relationship between a cleaning member that cleans the roller surface and a receiving member that receives toner removed by the cleaning member, relative to the roller. [Means for solving the problem]

[0010] In order to achieve the above object, the first configuration of the present invention is an intermediate transfer unit including an intermediate transfer belt, a drive roller, a tension roller, a primary transfer member, a belt cleaning device, and a roller cleaning mechanism. The intermediate transfer belt is endless and is disposed adjacent to an image carrier on which a toner image is formed. The drive roller is disposed at one end of the intermediate transfer belt in the traveling direction, and applies a rotational driving force to the intermediate transfer belt. The tension roller is disposed at the other end of the intermediate transfer belt in the traveling direction, and applies a predetermined tension to the intermediate transfer belt together with the drive roller. The primary transfer member is disposed opposite the image carrier across the intermediate transfer belt, and transfers the toner image formed on the image carrier onto the intermediate transfer belt. The belt cleaning device is disposed opposite the tension roller across the intermediate transfer belt, and removes residual toner on the intermediate transfer belt. The roller cleaning mechanism is disposed opposite the tension roller on the inside of the intermediate transfer belt, and cleans the surface of the tension roller. The roller cleaning mechanism includes a cleaning member that contacts the surface of the tension roller to remove foreign matter adhering to the tension roller, a receiving member disposed below the cleaning member to receive the foreign matter removed by the cleaning member, and a support frame that supports the cleaning member and the receiving member. The support frame is supported by a bearing portion that rotatably supports the rotation shaft of the tension roller. Effect of the Invention

[0011] According to the first aspect of the present invention, the support frame that supports the cleaning member and the receiving member is supported by the bearings of the tension roller, so that the positional relationship of the cleaning member and the receiving member with respect to the tension roller is always kept constant. Therefore, the contact state of the cleaning member and the receiving member with the surface of the tension roller is stable, and it is possible to effectively prevent poor cleaning due to poor contact of the cleaning member and the falling of foreign matter due to poor contact of the receiving member. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a cross-sectional view showing a schematic configuration of a color printer 100 equipped with an intermediate transfer unit 30 of the present invention. [Diagram 2] FIG. 1 is a side cross-sectional view showing a configuration of an intermediate transfer unit 30 according to an embodiment of the present invention that is installed in a color printer 100. [Diagram 3] FIG. 3 is an enlarged view of the area around the tension roller 11 in FIG. 2. [Figure 4] 3 is a perspective view of the tension roller 11 and its surroundings in FIG. 2; [Diagram 5] 1 is a perspective view of the roller cleaning mechanism 40 seen from above; [Figure 6] FIG. 1 is a perspective view of the roller cleaning mechanism 40 seen from below. [Figure 7] 1 is a plan view of the roller cleaning mechanism 40 and the tension roller 11 viewed from above. [Figure 8] FIG. 4 is a perspective view of a first frame 46 constituting the roller cleaning mechanism 40. [Figure 9] FIG. 4 is a perspective view of a second frame 47 constituting the roller cleaning mechanism 40. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a schematic cross-sectional view of a color printer 100 according to one embodiment of the present invention. Within the main body of the color printer 100, four image forming units Pa, Pb, Pc, and Pd are arranged in this order from the upstream side in the transport direction (the left side in Fig. 1). These image forming units Pa to Pd are provided corresponding to images of four different colors (cyan, magenta, yellow, and black), and sequentially form images of cyan, magenta, yellow, and black through the respective processes of charging, exposure, development, and transfer.

[0014] These image forming stations Pa to Pd are provided with photoconductor drums 1a, 1b, 1c, and 1d that carry visible images (toner images) of the respective colors, respectively. Furthermore, an intermediate transfer belt 8 that rotates counterclockwise in FIG. 1 is provided adjacent to each of the image forming stations Pa to Pd.

[0015] When image data is input from a host device such as a personal computer, first, the surfaces of the photoconductor drums 1a-1d are uniformly charged by the charging devices 2a-2d. Next, the exposure device 5 irradiates light according to the image data, and electrostatic latent images according to the image data are formed on the photoconductor drums 1a-1d. The developing devices 3a-3d are filled with a predetermined amount of two-component developer (hereinafter, simply referred to as developer) containing toner of each color (positively charged toner here) of cyan, magenta, yellow, and black by the toner containers 4a-4d, and the toner in the developer is supplied to the photoconductor drums 1a-1d by the developing devices 3a-3d and electrostatically adheres to them. As a result, a toner image according to the electrostatic latent image formed by exposure from the exposure device 5 is formed.

[0016] Then, an electric field is applied between the primary transfer rollers 6a-6d and the photoconductor drums 1a-1d by the primary transfer rollers 6a-6d at a predetermined transfer voltage, and the cyan, magenta, yellow and black toner images on the photoconductor drums 1a-1d are primarily transferred onto the intermediate transfer belt 8. Toner and the like remaining on the surfaces of the photoconductor drums 1a-1d after the primary transfer is removed by cleaning devices 7a-7d.

[0017] The transfer paper P onto which the toner image is transferred is stored in a paper cassette 16a located at the bottom of the color printer 100, or placed on a manual feed tray 16b located on the side of the color printer 100. The transfer paper P in the paper cassette 16a or on the manual feed tray 16b is transported at a predetermined timing through the paper transport path 17 via the paper feed roller 12a and the registration roller pair 12b to a nip portion (secondary transfer nip portion N, see FIG. 2) between the intermediate transfer belt 8 and a secondary transfer roller 9 provided adjacent to the intermediate transfer belt 8. The transfer paper P onto which the toner image has been secondarily transferred is transported to the fixing unit 13. Toner and the like remaining on the surface of the intermediate transfer belt 8 is removed by a belt cleaning device 19.

[0018] The transfer paper P transported to the fixing section 13 is heated and pressurized by the pair of fixing rollers 13a, so that the toner image is fixed onto the surface of the transfer paper P, and a predetermined full-color image is formed. The transfer paper P on which the full-color image has been formed is discharged directly from the paper transport path 17 via the pair of discharge rollers 15 to the discharge tray 20 (or after being diverted to the reversing transport path 18 by the branching section 14 and images are formed on both sides).

[0019] 2 is a side cross-sectional view showing the configuration around the intermediate transfer unit 30 mounted on the color printer 100 of this embodiment. As shown in FIG. 2, the intermediate transfer unit 30 has a side frame 30a, an upper frame 30b, an intermediate transfer belt 8, primary transfer rollers 6a to 6d, a drive roller 10, a tension roller (stretching roller) 11, a belt cleaning device 19, and a roller cleaning mechanism 40.

[0020] The side frames 30a are arranged in pair at both ends in the width direction of the intermediate transfer belt 8, and rotatably support the drive roller 10, the tension roller 11, and the primary transfer rollers 6a to 6d. The top frame 30b is fixed to the upper parts of the pair of side frames 30a in a bridging manner. The toner containers 4a to 4d (see FIG. 1) are placed on the top of the top frame 30b.

[0021] The intermediate transfer belt 8 is an endless belt stretched over a drive roller 10 and a tension roller 11, and the cyan, magenta, yellow and black toner images on the photosensitive drums 1a to 1d are primarily transferred onto the intermediate transfer belt 8. For example, the intermediate transfer belt 8 is made of polyimide resin or PVDF (polyvinylidene fluoride) mixed with a conductive material such as an ionic conductive material or conductive carbon to impart conductivity. In this embodiment, a conductive belt made of polyimide resin is used.

[0022] The drive roller 10 is disposed at one end in the belt travel direction (the travel direction of the surface of the intermediate transfer belt 8 facing the image forming units Pa to Pd). A belt drive motor (not shown) is connected to the drive roller 10 via a gear train (not shown). The drive roller 10 rotates (rotates counterclockwise in FIG. 2) while in contact with the inner circumferential surface of the intermediate transfer belt 8, thereby applying a rotational drive force in the counterclockwise direction to the intermediate transfer belt 8. The tension roller 11 is disposed at the other end in the belt travel direction. The tension roller 11 contacts the inner circumferential surface of the intermediate transfer belt 8, and applies a predetermined tension to the intermediate transfer belt 8 together with the drive roller 10.

[0023] In this embodiment, the driving roller 10 and tension roller 11 are rollers whose outer circumferential surfaces that come into contact with the intermediate transfer belt 8 are anodized. More specifically, the outer circumferential surfaces of the tension roller 11 and driving roller 10 have a two-layer structure of an aluminum layer (conductive layer) and an anodized layer (insulating layer), and the intermediate transfer belt 8 is supported from the inside with the anodized layer in contact with the inner circumferential surface of the intermediate transfer belt 8, whereby a rotational driving force is transmitted from the driving roller 10 to the intermediate transfer belt 8, and the rotational driving force is transmitted to the tension roller 11 via the intermediate transfer belt 8.

[0024] The primary transfer rollers 6a to 6d are in contact with the photosensitive drums 1a to 1d via the intermediate transfer belt 8. A transfer voltage power supply (not shown) is connected to the primary transfer rollers 6a to 6d. By applying a primary transfer voltage of the opposite polarity (negative polarity) to that of the toner to the primary transfer rollers 6a to 6d, the toner images on the photosensitive drums 1a to 1d are attracted to the primary transfer rollers 6a to 6 (the intermediate transfer belt 8 side) and primarily transferred onto the intermediate transfer belt 8.

[0025] The belt cleaning device 19 is disposed at a position facing the tension roller 11 with the intermediate transfer belt 8 interposed therebetween. The belt cleaning device 19 removes foreign matter such as toner and paper powder (hereinafter referred to as toner, etc.) remaining on the intermediate transfer belt 8.

[0026] The roller cleaning mechanism 40 is disposed at a position facing the tension roller 11 on the inner side of the intermediate transfer belt 8. The roller cleaning mechanism 40 removes toner and the like adhering to the surface of the tension roller 11. The detailed configurations of the belt cleaning device 19 and the roller cleaning mechanism 40 will be described later.

[0027] Figures 3 and 4 are an enlarged view and a perspective view, respectively, of the tension roller 11 and its periphery in Figure 2. For ease of explanation, the intermediate transfer belt 8 is omitted in Figure 4. As shown in Figures 3 and 4, the belt cleaning device 19 includes a belt cleaning blade 33 and a transport spiral 35 in a housing 31.

[0028] The belt cleaning blade 33 is fixed on the downstream side (lower side in FIG. 3) of the housing 31 with respect to the rotation direction of the tension roller 11 (counterclockwise direction in FIG. 3), with its tip facing upstream in the rotation direction of the tension roller 11 (counter direction, upward in FIG. 3). The tip of the belt cleaning blade 33 is pressed against the tension roller 11 via the intermediate transfer belt 8, and scrapes off foreign matter such as residual toner adhering to the intermediate transfer belt 8. For example, a blade made of polyurethane rubber is used as the belt cleaning blade 33. The material, hardness, dimensions, amount of bite into the intermediate transfer belt 8, pressure, etc. of the belt cleaning blade 33 are appropriately set according to the specifications of the intermediate transfer belt 8.

[0029] The transport spiral 35 transports the toner and other particles scraped off from the intermediate transfer belt 8 by the belt cleaning blade 33 to a waste toner collection container (not shown) outside the housing 31.

[0030] 5 and 6 are perspective views of the roller cleaning mechanism 40 as seen from above and below, respectively. FIG. 7 is a plan view of the roller cleaning mechanism 40 and the tension roller 11 as seen from above. The roller cleaning mechanism 40, which is a characteristic feature of the present invention, will be described in detail with reference to FIGS. 3 and 4. The roller cleaning mechanism 40 has a cleaning blade 41, a receiving member 43, and a support frame 45.

[0031] The cleaning blade 41 is fixed at a predetermined angle with its tip facing upstream in the rotation direction of the tension roller 11 (counter direction, lower left direction in FIG. 3). The tip of the cleaning blade 41 contacts the surface of the tension roller 11 and scrapes off toner and the like adhering to the surface of the tension roller 11. The dimension w2 of the cleaning blade 41 in the longitudinal direction (width direction of the intermediate transfer belt 8) is greater than the axial length w1 of the tension roller 11.

[0032] The receiving member 43 is fixed at a predetermined angle below the cleaning blade 41, with its tip facing downstream in the rotation direction of the tension roller 11 (upper left direction in FIG. 3). The receiving member 43 receives toner and the like scraped off from the surface of the tension roller 11 by the cleaning blade 41. A dimension w3 in the longitudinal direction of the receiving member 43 (width direction of the intermediate transfer belt 8) is larger than a dimension w2 in the longitudinal direction of the cleaning blade 41.

[0033] For example, a synthetic resin flexible film is used as the material for the cleaning blade 41 and the receiving member 43. In this embodiment, the cleaning blade 41 is made of a polyethylene terephthalate (PET) film having a thickness of 0.25 mm, and the receiving member 43 is made of a polyethylene terephthalate (PET) film having a thickness of 0.05 mm.

[0034] The support frame 45 is formed by bending a metal plate into a predetermined shape, and holds the cleaning blade 41 and the receiving member 43. The support frame 45 is made up of a first frame 46 and a second frame 47.

[0035] 8 and 9 are perspective views of the first frame 46 and the second frame 47 that constitute the support frame 45, respectively. As shown in FIG. 8, the first frame 46 has a blade holding portion 46a and a pair of support portions 46b. The blade holding portion 46a extends along the axial direction of the tension roller 11, and the cleaning blade 41 is fixed to the blade holding portion 46a. The pair of support portions 46b are formed by bending both longitudinal ends of the blade holding portion 46a vertically. The support portions 46b have an engagement portion 50, a positioning boss 51, a first screw hole 53, and a second screw hole 55.

[0036] The engagement portion 50 engages with a bearing portion 70 (see FIG. 7) that rotatably supports the rotating shaft 11a of the tension roller 11. The positioning boss 51 fits into a positioning hole (not shown) formed in the side frame 30a to restrict rotation of the support portion 46b and position the support frame 45 relative to the side frame 30a. A first screw 60 for fixing the support frame 45 to the side frame 30a is fastened into the first screw hole 53. A second screw 61 for fixing the second frame 47 to the first frame 46 is fastened into the second screw hole 55.

[0037] 9, the second frame 47 has a receiving member holding portion 47a and a pair of connecting portions 47b. The receiving member holding portion 47a extends along the axial direction of the tension roller 11 and approximately parallel to the blade holding portion 46a of the first frame 46, and the receiving member 43 is fixed thereto. The pair of connecting portions 47b are formed at both longitudinal ends of the receiving member holding portion 47a and have third screw holes 57. Second screws 61 for fixing the second frame 47 to the first frame 46 are fastened into the third screw holes 57.

[0038] When assembling the roller cleaning mechanism 40, first, the cleaning blade 41 is fixed to the blade holding portion 46a of the first frame 46. Also, the receiving member 43 is fixed to the receiving member holding portion 47a of the second frame 47. The cleaning blade 41 and the receiving member 43 are fixed using double-sided adhesive tape or the like.

[0039] Next, the second frame 47 is attached to the first frame 46 to form the support frame 45. More specifically, the first frame 46 and the second frame 47 are combined so that the third screw hole 57 formed in the connecting portion 47b of the second frame 47 overlaps with the second screw hole 55 formed in the support portion 46b of the first frame 46. In this state, the second screw 61 is fastened into the second screw hole 55 and the third screw hole 57 to fix the first frame 46 and the second frame 47 together. In this manner, the assembly of the roller cleaning mechanism 40 is completed.

[0040] Thereafter, the engaging portion 50 formed on the support portion 46b is engaged with the bearing portion 70 of the tension roller 11, and the positioning boss 51 is fitted into a positioning hole (not shown) formed in the side frame 30a. In this state, a first screw 60 is fastened into the first screw hole 53 and a screw hole (not shown) in the side frame 30a, and the support frame 45 is fixed to the side frame 30a. In this manner, the attachment of the roller cleaning mechanism 40 to the intermediate transfer unit 30 is completed.

[0041] According to the configuration of this embodiment, by providing a roller cleaning mechanism 40 that cleans the surface of the tension roller 11 that stretches the intermediate transfer belt 8, it is possible to suppress adhesion of scattered toner, paper powder, and the like to the tension roller 11. As a result, it is possible to reduce the occurrence of concave scratches on the back surface and convex scratches on the front surface of the intermediate transfer belt 8 caused by toner, etc. solidified by the tensioning force between the intermediate transfer belt 8 and the tension roller 11. Therefore, it is possible to effectively suppress the occurrence of transfer defects caused by unevenness on the surface of the intermediate transfer belt 8, and the service life (lifespan) of the intermediate transfer belt 8 can also be extended.

[0042] Furthermore, because the support frame 45 to which the cleaning blade 41 and the receiving member 43 are fixed is supported by the bearing portion 70 of the tension roller 11, the positional relationship of the cleaning blade 41 and the receiving member 43 with respect to the tension roller 11 is always maintained constant. This stabilizes the contact state of the cleaning blade 41 and the receiving member 43 with the surface of the tension roller 11, effectively preventing poor cleaning of the tension roller 11 due to poor contact of the cleaning blade 41 and preventing foreign matter from falling off the receiving member 43 due to poor contact of the receiving member 43.

[0043] Moreover, the support frame 45 is composed of a first frame 46 to which the cleaning blade 41 is fixed, and a second frame 47 to which the receiving member 43 is fixed. With this configuration, by combining the first frame 46 to which the cleaning blade 41 is fixed with the second frame 47 to which the receiving member 43 is fixed, when either the cleaning blade 41 or the receiving member 43 is fixed, the other does not get in the way, improving the ease of assembly.

[0044] Furthermore, if the layout is such that the second screws 61 are accessible while the roller cleaning mechanism 40 is attached to the intermediate transfer unit 30, it becomes possible to make only the second frame 47 detachable. With this configuration, it becomes possible to replace the receiving member 43 on which toner and the like have accumulated, thereby extending the service life (life) of the roller cleaning mechanism 40.

[0045] In this embodiment, a conductive resin belt having no elastic layer is used as the intermediate transfer belt 8, and a roller having an anodized outer circumferential surface is used as the tension roller 11. Therefore, toner and the like is easily compressed and solidified between the intermediate transfer belt 8 and the tension roller 11, and uneven scratches are easily caused on the intermediate transfer belt 8. Therefore, it is particularly effective to provide the roller cleaning mechanism 40 having the above configuration in the intermediate transfer unit 30 of this embodiment in which the intermediate transfer belt 8 is a resin belt and the outer circumferential surface of the tension roller 11 is made of metal.

[0046] The present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present invention. For example, in the above embodiment, the cleaning blade 41 made of polyethylene terephthalate film is used to remove toner and the like adhering to the tension roller 11, but a cleaning blade 41 made of, for example, urethane rubber may be used. Alternatively, instead of the cleaning blade 41, other cleaning members such as a cleaning brush or a cleaning roller may be used.

[0047] In addition, in the above embodiment, a configuration including a belt cleaning blade 33 and a conveying spiral 35 is used as the belt cleaning device 19 for removing residual toner on the intermediate transfer belt 8. However, it is also possible to use a belt cleaning device with a different configuration, such as a belt cleaning device including a fur brush that physically and electrostatically collects residual toner on the intermediate transfer belt 8, a collection roller that electrostatically collects toner, etc. adhering to the fur brush, and a scraper that physically removes toner, etc. adhering to the collection roller.

[0048] Furthermore, the present invention is not limited to the color printer 100 shown in FIG. 1, but can of course be applied to various intermediate transfer type image forming apparatuses such as color copiers, digital multifunction machines, and facsimiles. [Industrial Applicability]

[0049] The present invention can be used in an intermediate transfer unit that performs a primary transfer of a toner image on an image carrier onto an intermediate transfer belt. By utilizing the present invention, it is possible to provide an intermediate transfer unit and an image forming apparatus equipped with the same that can precisely regulate the positional relationship between a cleaning member that cleans the surface of a tension roller that tensions the intermediate transfer belt and a toner receiving portion that receives the toner removed by the cleaning member and the roller. [Explanation of symbols]

[0050] 1a to 1d Photoconductor drum (image carrier) 6a to 6d Primary transfer roller (primary transfer member) 8 Intermediate transfer belt 9 Secondary transfer roller 10 Drive roller 11 Tension roller 11a Rotation axis 19 Belt cleaning device 30 Intermediate transfer unit 33 Belt cleaning blade 35 Conveying Spiral 40 Roller cleaning mechanism 41 Cleaning blade (cleaning material) 43 Supporting member 45 Support Frame 46 1st Frame 46a Blade holder 46b Support part 47 2nd Frame 47a Receiving member holding portion 47b Connection part 50 Engagement part 51 Positioning boss 70 Bearing section 100 Color printers (image forming devices) Pa~Pd Image forming section

Claims

1. an endless intermediate transfer belt disposed adjacent to an image carrier on which a toner image is formed; a drive roller disposed at one end side of the intermediate transfer belt in a moving direction thereof and configured to apply a rotational drive force to the intermediate transfer belt; a tension roller that is disposed on the other end side of the intermediate transfer belt in the moving direction and that applies a predetermined tension to the intermediate transfer belt together with the drive roller; a primary transfer member disposed opposite the image carrier with the intermediate transfer belt interposed therebetween, the primary transfer member transferring the toner image formed on the image carrier onto the intermediate transfer belt; a belt cleaning device disposed opposite the tension roller with the intermediate transfer belt interposed therebetween, the belt cleaning device removing residual toner on the intermediate transfer belt; a roller cleaning mechanism disposed opposite the tension roller on the inner side of the intermediate transfer belt and configured to clean a surface of the tension roller; In an intermediate transfer unit comprising: The roller cleaning mechanism includes: a cleaning member that comes into contact with a surface of the tension roller to remove foreign matter adhering to the tension roller; a receiving member disposed below the cleaning member and receiving the foreign matter removed by the cleaning member; a support frame supporting the cleaning member and the receiving member; wherein the support frame is supported by a bearing portion that rotatably supports a rotation shaft of the tension roller.

2. 2. The intermediate transfer unit according to claim 1, wherein the support frame has a first frame that holds the cleaning member and a second frame that holds the receiving member, the second frame being detachable from the first frame.

3. 3. The intermediate transfer unit according to claim 2, wherein the second frame is detachable from the first frame in a state in which the roller cleaning mechanism is attached to the intermediate transfer unit.

4. the first frame extends along the axial direction of the tension roller and has a holding portion that holds the cleaning member, and a pair of support portions that are formed by bending both ends of the holding portion vertically, 4. The intermediate transfer unit according to claim 2, wherein the support portion has an engagement portion that engages with the bearing portion, and a positioning boss that positions the support frame relative to the side frame of the intermediate transfer unit.

5. 5. The intermediate transfer unit according to claim 1, wherein when the axial length of the tension roller is w1, and the dimensions of the cleaning member and the receiving member in the width direction of the intermediate transfer belt are w2 and w3, respectively, the relationship w1<w2<w3 holds.

6. 6. The intermediate transfer unit according to claim 1, wherein the tension roller has an outer circumferential surface that comes into contact with the intermediate transfer belt and is made of metal.

7. 7. The intermediate transfer unit according to claim 1, wherein the intermediate transfer belt is a conductive resin belt having no elastic layer.

8. An intermediate transfer unit according to any one of claims 1 to 7, a plurality of image forming units each including the image carrier and forming the toner image on the image carrier; An image forming apparatus comprising:

Images