JP2018055040A - Intermediate transfer unit and image forming apparatus including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an intermediate transfer unit capable of improving cleanability, while saving space and an image forming apparatus including the intermediate transfer unit.SOLUTION: An intermediate transfer unit 30 includes an intermediate transfer belt 8, a fur brush 41 which comes into contact with the outer peripheral surface of the intermediate transfer belt 8, while being rotated and to which a bias having a polarity reverse to that of toner is applied, to remove residual toner on the outer peripheral surface of the intermediate transfer belt 8, a recovery roller 43 which recovers waste toner adhered to the fur brush 41, a pre-brush 60 which is arranged on the upstream side of the fur brush 41 in the rotational direction of the intermediate transfer belt 8 and comes into contact with the outer peripheral surface of the intermediate transfer belt 8, to apply an electric charge having the same polarity as that of the residual toner, and a pressing member 70 which presses the pre-brush 60 to the intermediate transfer belt 8 and is made of a non-conductive resin. The rotation center O41 of the fur brush 41 is arranged above the rotation center O43 of the recovery roller 43.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an intermediate transfer unit and an image forming apparatus including the same, and more particularly, a cleaning member that removes residual toner on an outer peripheral surface of an intermediate transfer belt, a collection roller that collects waste toner attached to the cleaning member, and a cleaning device The present invention relates to an intermediate transfer unit including a pre-cleaning member disposed upstream of the member in the rotation direction of the intermediate transfer belt, and an image forming apparatus including the intermediate transfer unit.

  In an image forming apparatus using an electrophotographic system such as a copying machine, a printer, a facsimile, etc., a powder developer is mainly used, and a toner image is transferred from a photosensitive drum to an intermediate transfer belt, and the toner image is recorded on a recording medium. A process of performing a fixing process after the image is transferred to the top is common. The toner remaining on the outer peripheral surface of the intermediate transfer belt is removed by a cleaning device, and a new toner image is formed.

  As such a cleaning device, a fur brush (cleaning member) that removes toner from the outer peripheral surface of the intermediate transfer belt, a collection roller that collects toner from the fur brush, a cleaning blade that scrapes off the toner on the surface of the collection roller, A discharge screw that discharges the toner scraped off from the surface of the collection roller to the outside, and a pre-load that is disposed upstream of the fur brush in the rotation direction of the intermediate transfer belt, and applies charge to the toner on the outer peripheral surface of the intermediate transfer belt. A cleaning device including a cleaning member is known. In this cleaning device, a pre-cleaning member is held so as to be swingable in a direction in which the pre-cleaning member is brought into contact with and separated from the outer peripheral surface of the intermediate transfer belt (vertical direction), and the pre-cleaning member is pressed against the outer peripheral surface of the intermediate transfer belt And a biasing member that biases the pressing member toward the outer peripheral surface of the intermediate transfer belt.

  A cleaning member that removes toner from the outer peripheral surface of the intermediate transfer belt, a collection roller that collects waste toner adhering to the cleaning member, and a pre-cleaning that is disposed upstream of the cleaning member in the rotation direction of the intermediate transfer belt. An intermediate transfer unit having a member is disclosed in Patent Document 1, for example.

JP 2010-122610 A

  By the way, when the fur brush is arranged below the collection roller, if toner or paper dust falls from the fur brush or the collection roller and collects in the cleaning device, the accumulated toner is transferred to the intermediate by rotation of the fur brush. The image reattaches to the belt and an image defect occurs. In order to improve this, it is conceivable to dispose the fur brush above the collection roller.

  However, in the conventional cleaning device provided with a metal pressing member that holds the pre-cleaning member so as to be swingable, when the fur brush is disposed above the recovery roller, it is between the pressing member and the fur brush. The distance is reduced, and electric discharge occurs between the fur brush and the pressing member. For this reason, since it is necessary to arrange | position a pressing member away from a fur brush, there exists a problem that space saving is difficult.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an intermediate transfer unit capable of improving cleaning performance while saving space, and the intermediate transfer unit. An image forming apparatus is provided.

  In order to achieve the above object, an intermediate transfer unit having a first configuration according to the present invention is in contact with an intermediate transfer belt to which a toner image is transferred from an image forming unit, while rotating and contacting the outer peripheral surface of the intermediate transfer belt. A cleaning member that removes residual toner on the outer peripheral surface of the intermediate transfer belt by applying a bias having a polarity opposite to that of the intermediate transfer belt, and a collection roller that contacts the cleaning member while rotating and collects waste toner attached to the cleaning member The intermediate transfer belt is disposed upstream of the cleaning member in the rotational direction of the intermediate transfer belt, and is provided to be movable substantially perpendicular to the outer peripheral surface of the intermediate transfer belt. A pre-cleaning member that imparts a polar charge, and a pressing portion made of a non-conductive resin that presses the pre-cleaning member against the outer peripheral surface of the intermediate transfer belt And, equipped with a. The rotation center of the cleaning member is disposed above the rotation center of the collection roller.

  According to the first configuration of the present invention, by providing the pre-cleaning member on the upstream side in the rotation direction of the intermediate transfer belt with respect to the cleaning member, it is possible to improve the cleaning performance for the intermediate transfer belt. Also, by arranging the rotation center of the cleaning member above the rotation center of the collection roller, even if the toner or paper dust drops from the cleaning member or the collection roller and collects it, Is not reattached to the intermediate transfer belt by the rotation of the cleaning member, so that the cleaning property for the intermediate transfer belt can be further improved.

  Even if the distance between the cleaning member and the pressing member is reduced by forming the pressing member that presses the pre-cleaning member against the outer peripheral surface of the intermediate transfer belt with a non-conductive resin, the cleaning member It is possible to suppress the occurrence of discharge between the pressure member and the pressing member. For this reason, it is not necessary to dispose the pressing member away from the cleaning member, so that the space of the intermediate transfer unit can be saved.

1 is a schematic diagram illustrating a structure of an image forming apparatus including an intermediate transfer unit according to an embodiment of the present invention. FIG. 2 is an enlarged view of the vicinity of an image forming unit Pa in FIG. 1. FIG. 2 is a perspective view illustrating a structure of an intermediate transfer unit according to an embodiment of the present invention. FIG. 3 is a cross-sectional view illustrating a structure around a belt cleaning unit of an intermediate transfer unit according to an embodiment of the present invention. FIG. 3 is a perspective view showing a structure around a pre-brush of an intermediate transfer unit according to an embodiment of the present invention from the lower side. FIG. 4 is a perspective view showing a structure around a pressing member of an intermediate transfer unit according to an embodiment of the present invention from the lower side. FIG. 4 is a diagram illustrating a structure around a side surface portion of a pre-brush of an intermediate transfer unit according to an embodiment of the present invention. FIG. 3 is a perspective view showing a structure around a belt cleaning unit of an intermediate transfer unit according to an embodiment of the present invention, and showing a state where an upper cover member is removed. FIG. 3 is a perspective view showing a structure around a belt cleaning unit of an intermediate transfer unit according to an embodiment of the present invention. FIG. 4 is a perspective view illustrating the structure of an upper cover member and a pressing member of an intermediate transfer unit according to an embodiment of the present invention. It is the perspective view which showed from the lower side the structure of the press member periphery of the intermediate transfer unit of the 1st modification of this invention. FIG. 10 is a perspective view illustrating a structure of an upper cover member of an intermediate transfer unit according to a second modification of the present invention. FIG. 10 is a cross-sectional view illustrating a structure around a belt cleaning unit of an intermediate transfer unit according to a second modification of the present invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic diagram illustrating a configuration of an image forming apparatus 100 including an intermediate transfer unit 30 according to an embodiment of the present invention. FIG. 2 is an enlarged view of the vicinity of an image forming unit Pa in FIG.

  The image forming apparatus 100 of FIG. 1 has the following configuration. In the main body of the image forming apparatus 100, four image forming portions Pa, Pb, Pc, and Pd are sequentially arranged from the upstream side in the transport direction (the right side in FIG. 1). These image forming portions Pa to Pd are provided corresponding to images of four different colors (cyan, magenta, yellow, and black), and cyan, magenta, and yellow are respectively performed by charging, exposure, development, and transfer processes. And a black image are sequentially formed.

  These image forming portions Pa to Pd are provided with photosensitive drums 1a, 1b, 1c and 1d which carry visible images (toner images) of the respective colors, and are further illustrated by a driving means (not shown). 1, an intermediate transfer belt 8 that rotates in the clockwise direction is provided adjacent to each of the image forming portions Pa to Pd.

  The transfer paper P onto which the toner image is transferred is accommodated in a paper cassette 16 at the lower part of the main body of the image forming apparatus 100, and is conveyed to the secondary transfer roller 9 via the paper feed roller 12a and the registration roller pair 12b. .

  Next, the image forming units Pa to Pd will be described. Around and below the photosensitive drums 1a to 1d arranged to be rotatable, chargers 2a, 2b, 2c and 2d for charging the photosensitive drums 1a to 1d, and image information to each of the photosensitive drums 1a to 1d. The exposure unit 4 for exposing the toner, the developing units 3a, 3b, 3c and 3d for forming toner images on the photosensitive drums 1a to 1d, and the developer (toner) remaining on the photosensitive drums 1a to 1d are removed. Cleaning devices 5a, 5b, 5c and 5d are provided.

  Hereinafter, the image forming unit Pa will be described in detail with reference to FIG. 2. However, the image forming units Pb to Pd have basically the same configuration, and thus description thereof is omitted. As shown in FIG. 2, a charger 2a, a developing unit 3a, and a cleaning device 5a are disposed around the photosensitive drum 1a along the drum rotation direction (counterclockwise direction in FIG. 1). A primary transfer roller 6 a is disposed with 8 interposed therebetween. Further, a belt cleaning unit 19 facing the tension roller 11 with the intermediate transfer belt 8 interposed therebetween is disposed on the upstream side in the rotation direction of the intermediate transfer belt 8 with respect to the photosensitive drum 1a. The belt transfer unit 19, the intermediate transfer belt 8, the tension roller 11, the primary transfer rollers 6 a to 6 d, the driving roller 10 described later, and the like constitute an intermediate transfer unit 30. A detailed configuration of the intermediate transfer unit 30 will be described later.

  Next, an image forming procedure in the image forming apparatus 100 will be described. When the start of image formation is input by the user, first, the surfaces of the photosensitive drums 1a to 1d are uniformly charged by the chargers 2a to 2d. Next, the exposure unit 4 irradiates the surfaces of the photosensitive drums 1a to 1d to form electrostatic latent images corresponding to the image signals on the photosensitive drums 1a to 1d. Each of the developing units 3a to 3d is filled with a predetermined amount of cyan, magenta, yellow, and black toner by a replenishing device (not shown). The toner is supplied onto the photosensitive drums 1a to 1d by the developing units 3a to 3d and electrostatically attached, whereby a toner image corresponding to the electrostatic latent image formed by exposure from the exposure unit 4 is formed. It is formed.

  The primary transfer rollers 6a to 6d apply an electric field at a predetermined transfer voltage between the primary transfer rollers 6a to 6d and the photosensitive drums 1a to 1d, and cyan, magenta, yellow, and yellow on the photosensitive drums 1a to 1d. A black toner image is primarily transferred onto the intermediate transfer belt 8. These four color images are formed with a predetermined positional relationship predetermined for forming a predetermined full-color image. Thereafter, the toner remaining on the surfaces of the photosensitive drums 1a to 1d is removed by the cleaning devices 5a to 5d in preparation for the subsequent formation of a new electrostatic latent image.

  When the intermediate transfer belt 8 starts to rotate in the clockwise direction as the driving roller 10 is rotated by a driving motor (not shown), the transfer paper P is adjacent to the intermediate transfer belt 8 from the registration roller pair 12b at a predetermined timing. The full color image is transferred to the secondary transfer roller 9 provided. The transfer paper P onto which the toner image is transferred is conveyed to the fixing unit 7. The toner remaining on the surface of the intermediate transfer belt 8 is removed by the belt cleaning unit 19.

  The transfer paper P conveyed to the fixing unit 7 is heated and pressed by a pair of fixing rollers, and the toner image is fixed on the surface of the transfer paper P, thereby forming a predetermined full-color image. The transfer paper P on which the full-color image is formed is distributed in the transport direction by the branching section 14 and is discharged to the discharge tray 17 as it is (or after being sent to the double-sided conveyance path 18 and printed on both sides). Is done.

  FIG. 3 is a perspective view showing the structure of the intermediate transfer unit 30 according to an embodiment of the present invention. FIG. 4 is a cross-sectional view showing the structure around the belt cleaning unit 19 of the intermediate transfer unit 30 according to the embodiment of the present invention. FIG. 3 and 4 show a state seen from the back side of the sheet of FIG.

  As shown in FIG. 3, the intermediate transfer unit 30 includes a unit main body 35 including two side frames 31, 32 and connection frames 33, 34 that connect the end portions of the side frames 31, 32, and a side frame. Primary transfer rollers 6a to 6d supported between 31 and 32, drive roller 10, tension roller 11 (both see FIG. 1), endless intermediate transfer belt 8 stretched between these rollers, unit main body The belt cleaning unit 19 is provided at the left end of FIG.

  As shown in FIG. 4, the belt cleaning unit 19 includes a fur brush (cleaning member) 41, a collection roller 43, a cleaning blade 45, and a discharge screw 47 in a housing 40. A drive input gear train (not shown) for inputting a drive force to 41, the collection roller 43, and the discharge screw 47 is disposed. The housing 40 may be configured integrally with the connection frame 33, or may be configured separately from the connection frame 33.

  The fur brush 41 is configured by winding a fiber made of an insulating resin such as acrylic or rayon and having conductivity with carbon or the like around a shaft made of SUS or the like. The fur brush 41 is disposed such that the rotation center O41 of the fur brush 41 is positioned above the rotation center O43 of the collection roller 43, and is disposed to face the tension roller 11 via the intermediate transfer belt 8. . The fur brush 41 rotates on the counter transfer direction (counterclockwise direction in FIG. 4) with respect to the moving direction of the intermediate transfer belt 8, and remains on the intermediate transfer belt 8 by applying a bias having a polarity opposite to that of the toner. To electrically adsorb foreign matter such as toner and paper dust (hereinafter referred to as toner). The adsorbed toner or the like adheres to the brush portion of the fur brush 41.

  The collection roller 43 is constituted by a shaft made of SUS or the like, or a shaft having a resistance layer such as anodized on the surface. The collection roller 43 rotates in the opposite direction (clockwise direction in FIG. 4) to the fur brush 41 while being in contact with the surface of the fur brush 41, and a bias having a polarity opposite to that of the toner is applied to the fur brush 41. Collect the adhered toner.

  The cleaning blade 45 is fixed to a holding member 48 made of sheet metal, and comes into contact with the collection roller 43 from the downstream side with respect to the rotation direction of the collection roller 43 (counter direction with respect to the moving direction of the surface of the collection roller 43). The collecting roller 43 is cleaned by scraping off the toner collected by the above.

  The discharge screw 47 is disposed in the waste toner container 40 a of the housing 40. The discharge screw 47 is constituted by a rotation shaft 47a extending in the longitudinal direction of the collection roller 43 (perpendicular to the paper surface of FIG. 4) and a spiral blade 47b provided on the peripheral surface of the rotation shaft 47a. The discharge screw 47 rotates in the clockwise direction of FIG. 4, thereby transporting the toner scraped off from the collection roller 43 by the cleaning blade 45 in the axial direction of the rotation shaft 47 a and discharging it to the outside of the housing 40.

  Inside the housing 40, a seal member 50 that is in contact with the entire length of the collection roller 43 is disposed so as to extend in the length direction of the collection roller 43. The seal member 50 is provided to prevent the toner scraped off by the cleaning blade 45 from flowing back from the waste toner container 40a to the fur brush 41 side, and contacts the collection roller 43 with a predetermined contact pressure. doing. Note that the seal member 50 is inclined downward as it moves away from the intermediate transfer belt 8, and the toner or the like that has dropped on the seal member 50 moves to the left in FIG. It falls into the accommodating part 40a.

  Further, the belt cleaning unit 19 is provided with a pre-brush (pre-cleaning member) 60 disposed on the upstream side in the rotation direction of the intermediate transfer belt 8 with respect to the fur brush 41. The pre-brush 60 is formed so as to extend in the width direction of the intermediate transfer belt 8 (perpendicular to the paper surface of FIG. 4), and is in contact with the outer peripheral surface of the intermediate transfer belt 8. Charge is applied to the toner remaining in the toner. The prebrush 60 includes a brush part 61 and a holding member 62 that holds the brush part 61.

  The brush portion 61 is formed of a fiber made of an insulating resin such as acrylic or rayon and made conductive with carbon or the like, and is held by a sheet metal holding member 62 made of SUS or the like. The holding member 62 is electrically connected to the bias applying unit 63, and a bias (for example, a positive potential bias) having the same polarity as the residual toner on the outer peripheral surface of the intermediate transfer belt 8 is applied by the bias applying unit 63. As a result, the toner and the like on the outer peripheral surface of the intermediate transfer belt 8 passing through the pre-brush 60 are charged to, for example, a positive potential, and thus are efficiently adsorbed by the fur brush 41 to which a reverse polarity (for example, negative potential) bias is applied. The

  The pre-brush 60 is configured to be movable substantially perpendicular to the outer peripheral surface of the intermediate transfer belt 8. Specifically, the holding member 62 is formed with a pair of side surfaces 62a (see FIG. 5) by bending downward both ends of the holding member 62 in the longitudinal direction (perpendicular to the paper surface of FIG. 4). Has been. The pair of side surface portions 62a is provided so as to be in sliding contact with the inner surfaces of the side surface frames 31 and 32 in the vertical direction. As shown in FIG. 5, a notch 62b that opens downward is formed at the center in the width direction of the side surface portion 62a (the left-right direction in FIG. 5). Guide notches 36 formed integrally with the side frames 31 and 32 are disposed in the notch 62b, and the notches 62b are guided on both end faces of the guide protrusion 36 (end faces in the left-right direction in FIG. 5). In this state, it can move up and down. 4, the upper surface of the holding member 62 is inclined downward in the left direction of FIG. 4 (or when the upper surface of the holding member 62 is pressed by a distal end portion 71a of the pressing member 70 described later, the upper surface of FIG. (Inclined downward toward the left).

  The belt cleaning unit 19 is provided with a plurality (three in this case) of pressing members 70 made of a non-conductive resin that presses the pre-brush 60 against the outer peripheral surface of the intermediate transfer belt 8. The three pressing members 70 are arranged at both ends and the center of the prebrush 60 so as to be equally spaced along the longitudinal direction of the prebrush 60 (perpendicular to the paper surface of FIG. 4).

  The pressing member 70 includes a plate-like portion 71 that extends in the horizontal direction and a biased portion 72 that extends downward from the rear end (left end in FIG. 4) of the plate-like portion 71. The biased portion 72 is biased in the horizontal direction (the right direction in FIG. 4) by a biasing member 80 made of a compression coil spring or the like. Further, an upper cover member 90 made of a non-conductive resin is provided so as to cover the upper portion of the fur brush 41 and the collection roller 43, a wall portion 91 protruding downward from the lower surface of the upper cover member 90, and an urging force An urging member 80 is disposed between the portion 72 and the portion 72. As shown in FIG. 6, mounting projections to which both ends of the biasing member 80 are respectively attached are formed on the wall portion 91 and the biased portion 72 so as to face each other.

  As shown in FIGS. 4 and 6, the plate-like portion 71 is slidable along the lower surface of the upper cover member 90. Moreover, while the front-end | tip part (right side edge part of FIG. 4) 71a of the plate-shaped part 71 is arrange | positioned between the upper cover member 90 and the prebrush 60, as for the plate-shaped part 71, the lower surface of the front-end | tip part 71a is upward. It is formed in the taper shape which inclines to. As a result, when the pressing member 70 is urged to the right in FIG. 4 by the urging member 80, the tip 71 a presses the pre-brush 60 against the outer peripheral surface of the intermediate transfer belt 8. Note that a gap is formed between the upper surface 36a of the guide protrusion 36 and the side surface portion 62a of the pre-brush 60 as shown in FIG. 7 in a state where the front end 71a presses the pre-brush 60 against the outer peripheral surface of the intermediate transfer belt 8. ing.

  As shown in FIG. 6, first engagement pieces 92 that engage with engagement protrusions 37 (see FIG. 8) provided on the inner surfaces of the side frames 31 and 32 are provided at both ends in the longitudinal direction of the upper cover member 90. Is formed. Further, a plurality of snap-fit shapes (four in this example) that are engaged with a plurality of (in this case, four) openings 33a (see FIG. 8) provided on the upper surface of the connection frame 33 are provided at the left end of the upper cover member 90 in FIG. Here, four) second engaging pieces 93 are formed. Then, as the first engagement piece 92 is engaged with the engagement protrusion 37 and the second engagement piece 93 is engaged with the opening 33a, the upper cover member 90 is side-faced as shown in FIG. It is attached to the frames 31 and 32 and the connection frame 33.

  Further, as shown in FIGS. 9 and 10, the upper cover member 90 has a plurality of (here, six) engagement holes 94 with which the pressing member 70 is engaged, in the longitudinal direction of the upper cover member 90. They are arranged at intervals. The engagement hole 94 is formed so as to extend in the sliding direction of the pressing member 70. On the upper surface of the plate-like portion 71 of the pressing member 70, engaging portions 71 b and 71 c that engage with the engaging hole 94 and are slidable along the engaging hole 94 are formed. The engaging portion 71b is formed in an L-shaped cross section, and the engaging portion 71c is formed in a snap fit shape. The pressing member 70 can be easily attached to the upper cover member 90 by engaging the engaging portion 71 c with the engaging hole 94 after engaging the engaging portion 71 b with the engaging hole 94. When the upper cover member 90 is attached to the unit main body 35 (the side frames 31 and 32 and the connection frame 33), the upper cover member 90 is attached to the unit main body 35 with the pressing member 70 attached to the upper cover member 90. .

  In the present embodiment, as described above, by providing the pre-brush 60 on the upstream side in the rotation direction of the intermediate transfer belt 8 with respect to the fur brush 41, the cleaning performance for the intermediate transfer belt 8 can be improved. Further, by arranging the rotation center O41 of the fur brush 41 above the rotation center O43 of the collection roller 43, toner and paper dust fall from the fur brush 41 and the collection roller 43 and accumulate in the housing 40. Even in this case, the accumulated toner or the like does not reattach to the intermediate transfer belt 8 due to the rotation of the fur brush 41, so that the cleaning property for the intermediate transfer belt 8 can be further improved.

  Even if the distance between the fur brush 41 and the pressing member 70 is reduced by forming the pressing member 70 that presses the pre-brush 60 against the outer peripheral surface of the intermediate transfer belt 8 with a non-conductive resin. It is possible to suppress the occurrence of discharge between the fur brush 41 and the pressing member 70. For this reason, since it is not necessary to arrange the pressing member 70 away from the fur brush 41, the space of the intermediate transfer unit 30 can be saved.

  Further, as described above, the pressing member 70 is provided so as to be slidable along the lower surface of the upper cover member 90. Therefore, unlike the case where the pressing member swings in the vertical direction as in a conventional cleaning device, It is not necessary to secure a space above the fur brush 41 so that the pressing member 70 can swing in the vertical direction. For this reason, the space for the intermediate transfer unit 30 can be further reduced.

  Moreover, the pressing member 70 is formed in the taper shape in which the lower surface of the front-end | tip part 71a inclines upwards. As a result, when the pressing member 70 slides in the horizontal direction, the tip end portion 71 a can easily press the pre-brush 60 against the outer peripheral surface of the intermediate transfer belt 8.

  Further, as described above, the upper cover member 90 is formed with the engagement hole 94 extending in the sliding direction of the pressing member 70. The pressing member 70 engages with the engagement hole 94 and is engaged with the engagement hole 94. Engaging portions 71 b and 71 c that are slidable along 94 are provided. Thereby, the pressing member 70 can be easily slid along the lower surface of the upper cover member 90. Further, since the upper cover member 90 can be attached to the side frames 31, 32 and the connection frame 33 in a state where the pressing member 70 is attached to the upper cover member 90, the assemblability of the intermediate transfer unit 30 can be improved. .

  Further, as described above, three pressing members 70 are provided in the longitudinal direction of the pre-brush 60 with a predetermined interval. Accordingly, it is possible to suppress the pressing force applied to the intermediate transfer belt 8 at the central portion in the longitudinal direction of the prebrush 60 from becoming smaller than the pressing force applied to the intermediate transfer belt 8 at both longitudinal ends of the prebrush 60. Can be uniformly pressed against the intermediate transfer belt 8.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, although an example in which the present invention is applied to a printer has been described, the present invention is not limited to this. Needless to say, a cleaning member such as a copying machine or a facsimile, a collection roller for collecting waste toner attached to the cleaning member, a pre-cleaning member disposed on the upstream side in the rotation direction of the intermediate transfer belt with respect to the cleaning member, The present invention can be applied to various image forming apparatuses including an intermediate transfer unit including

  Moreover, in the said embodiment, although shown about the example which provided the three pressing members 70, this invention is not limited to this. Two or four or more pressing members 70 may be provided. Further, for example, as in the first modified example of the present invention shown in FIG. 11, only one pressing member 70 is provided and extended in the longitudinal direction of the prebrush 60 so as to be in contact with substantially the entire longitudinal region of the prebrush 60. May be formed. In this case, the pre-brush 60 can be pressed more uniformly against the intermediate transfer belt 8.

  In the above embodiment, the pressing member 70 is formed separately from the upper cover member 90 and the pressing member 70 is slid with respect to the upper cover member 90. However, the present invention is not limited to this. Not limited to. For example, as in the second modification of the present invention shown in FIGS. 12 and 13, the pressing member 70 is formed integrally with the upper cover member 90, and the prebrush 60 is pressed against the intermediate transfer belt 8 by the restoring force of the pressing member 70. May be. In addition, it can suppress that the press position with respect to the prebrush 60 of the press member 70 changes by providing the press protrusion 70a contact | abutted with the prebrush 60 at the front-end | tip of the press member 70. FIG.

  Further, a configuration obtained by appropriately combining the configurations of the above-described embodiment and modification examples is also included in the technical scope of the present invention.

8 Intermediate transfer belt 30 Intermediate transfer unit 41 Fur brush (cleaning member)
43 Collection roller 60 Pre-brush (pre-cleaning member)
70 Pressing member 71a Tip portion 71b, 71c Engaging portion 80 Energizing member 90 Upper cover member 94 Engaging hole 100 Image forming apparatus O41, O43 Center of rotation Pa to Pd Image forming portion

Claims (6)

An intermediate transfer belt to which a toner image is transferred from an image forming unit;
A cleaning member that contacts the outer peripheral surface of the intermediate transfer belt while rotating and removes residual toner on the outer peripheral surface of the intermediate transfer belt by applying a bias having a polarity opposite to that of the toner;
A collection roller that contacts the cleaning member while rotating and collects the waste toner adhering to the cleaning member;
The intermediate transfer belt is disposed upstream of the cleaning member in the rotation direction of the intermediate transfer belt, and is provided to be movable substantially perpendicular to the outer peripheral surface of the intermediate transfer belt. A pre-cleaning member that imparts a charge of the same polarity as the residual toner;
A pressing member made of a non-conductive resin that presses the pre-cleaning member against the outer peripheral surface of the intermediate transfer belt;
With
The intermediate transfer unit, wherein the rotation center of the cleaning member is disposed above the rotation center of the recovery roller. An upper cover member made of a non-conductive resin that covers the cleaning member and the recovery roller;
A biasing member that biases the pressing member in a horizontal direction;
Further comprising
The pressing member is provided so as to be slidable along the lower surface of the upper cover member, and is formed in a tapered shape in which the lower surface of the tip portion is inclined upward,
The pressing member is urged by the urging member in a state where the distal end portion of the pressing member is disposed between the upper cover member and the pre-cleaning member, so that the distal end portion causes the pre-cleaning member to move. The intermediate transfer unit according to claim 1, wherein the intermediate transfer unit is pressed against the intermediate transfer belt. The upper cover member is formed with an engagement hole extending in the sliding direction of the pressing member,
The intermediate transfer unit according to claim 2, wherein the pressing member is provided with an engaging portion that engages with the engaging hole and is slidable along the engaging hole.   The intermediate transfer unit according to claim 1, wherein three or more pressing members are provided at a predetermined interval in the longitudinal direction of the pre-cleaning member.   The press member is formed so as to extend in the longitudinal direction of the pre-cleaning member, and contacts substantially the entire region in the longitudinal direction of the pre-cleaning member. The intermediate transfer unit described in 1.   An image forming apparatus comprising the intermediate transfer unit according to claim 1.

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