JP2006011269A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of stabilizing the cleaning performance of a cleaning member for a charging member. <P>SOLUTION: The image forming apparatus includes: the charging member 52 for charging an image carrier 50 while rotating in contact with the rotating image carrier 50; the cleaning member 100 having a brush 104 for cleaning the surface of the charging member 52, and a shaft 102 to which the brush 104 is attached; a frame 108 having long holes 110 in which the ends of the shaft 102 of the cleaning member 100 are inserted, and supporting the charging member 52 so that the charging member 52 is rotatable; and a contact/separation mechanism 112 for bringing the cleaning member 100 into contact with the charging member 52 and separating the cleaning member 100 from the charging member 52. The edge 110A of each long hole 110, which is on the side of the charging member 52, is formed flat. In addition, the face 102B of each end 102A of the shaft 102, which is opposite to the charging member 52, is formed flat as well. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus provided with a charging member that contacts a rotating image carrier while rotating and charges the image carrier, and a cleaning member that cleans the surface of the charging member.

  In an image forming apparatus such as an electrophotographic apparatus or an electrostatic recording apparatus, a surface of an image carrier such as a photosensitive member or a dielectric is charged before exposure for forming an electrostatic latent image. As a method for performing this charging process, there is a contact charging method in which a charging member is brought into contact with the surface of an image carrier to perform the charging process. This contact charging method has been widely adopted in recent years because it requires only a low voltage to be applied to the charging member and generates very little ozone.

  However, this contact charging method has a drawback that the reliability of charging uniformity is low. One of the causes is a problem that dirt adheres to the charging member. The contamination of the charging member is caused by adhesion of toner, discharge products, dust, paper powder, and the like when the charging member is brought into contact with the image carrier. When the charging member becomes dirty, abnormal discharge and unstable discharge are generated, and image quality defects such as fogging are caused. Further, non-uniform charging due to the contamination of the charging member becomes particularly noticeable when a DC voltage is applied, and image quality defects due to this can be a fatal problem for an image forming apparatus for high image quality.

  For this reason, many proposals have been made to remove dirt directly by bringing the cleaning member into contact with the charging member. However, many of them are inferior in maintainability as a cleaning member because clogging occurs in the cleaning member and dirt is accumulated. In addition, when the cleaning member comes into contact with or separates from the charging member, there is a problem that dirt is reattached to the charging member.

Further, in order to solve such problems, there has been proposed one in which a brush as a cleaning member is swung while being in contact with a charging member (see, for example, Patent Document 1). However, in this method, since the contact distance of the brush with the charging member becomes unstable, there is a possibility that the cleaning performance varies.
JP 2003-263010 A

  Accordingly, an object of the present invention is to provide an image forming apparatus that can stabilize the cleaning performance of the cleaning member relative to the charging member in view of such problems.

  In order to achieve the above object, an image forming apparatus according to claim 1 of the present invention includes a charging member that contacts a rotating image carrier while rotating and charges the image carrier, and the charging member. A cleaning member comprising a brush for cleaning the surface of the member and a shaft to which the brush is attached, a long hole through which an end of the shaft of the cleaning member is inserted, and a frame that rotatably supports the charging member And a contact / separation mechanism for contacting and separating the cleaning member with respect to the charging member, and a peripheral edge portion of the elongated hole on the charging member side is formed in a planar shape, and an end portion of the shaft A surface facing the charging member is formed in a flat shape.

  According to the first aspect of the present invention, in the elongated hole of the frame, the edge portion on the charging member side is formed in a flat shape, and the surface facing the charging member is formed in a flat shape in the end portion of the shaft. Therefore, when the cleaning member comes into contact with the charging member, the flat portion of the shaft comes into contact with the flat portion of the long hole. For this reason, the position and angle of the brush with respect to the charging member are positioned with high accuracy, and even if the charging member rotates, rotation (rotation) of the brush is suppressed. Therefore, the cleaning performance of the cleaning member with respect to the charging member can be stabilized.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, at least an end portion of the shaft inserted through the elongated hole is formed of metal.

  In the invention according to claim 2, since at least the end portion of the shaft that is inserted into the long hole is formed of metal, even if the number of times that the flat portion of the shaft abuts the flat portion of the long hole increases, the shaft The shape is maintained with high accuracy. Further, even if the shaft is downsized, the strength can be sufficiently secured, so that the deflection of the central portion of the shaft can be suppressed. Therefore, the contact state of the brush with the charging member can be suitably maintained.

  Furthermore, the image forming apparatus according to claim 3 is the image forming apparatus according to claim 1 or 2, wherein the end portion of the shaft in the rotation direction of the charging member and the elongated hole are A predetermined clearance is provided.

  In the third aspect of the present invention, since the predetermined clearance is provided between the end of the shaft and the long hole in the rotation direction of the charging member, the brush is rotated by the charging member by the clearance. Go around. That is, the brush can move slightly in the rotation direction of the charging member. For this reason, the area | region of the brush front-end | tip which contacts a charging member can be expanded, and the replacement time by the cleaning performance of a cleaning member falling can be extended (life extension of a cleaning member can be achieved).

  The image forming apparatus according to claim 4 is the image forming apparatus according to any one of claims 1 to 3, wherein the contact / separation mechanism pushes up both end portions of the shaft to form the charging member. When the brush is brought into contact with the charging member, the brush is separated from the charging member by the weight of the cleaning member.

  In the invention according to the fourth aspect, the contact / separation mechanism only needs to be configured so as to perform only the operation of pushing up both end portions of the shaft, so that the mechanism can be simplified.

  As described above, according to the present invention, it is possible to provide an image forming apparatus that can stabilize the cleaning performance of the cleaning member with respect to the charging member.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS The best mode for carrying out the present invention will be described below in detail based on the embodiments shown in the drawings. As shown in FIG. 1, the image forming apparatus 10 has an image forming apparatus main body 12, and an opening / closing cover 16 that is rotatable around a rotation fulcrum 14 is provided on the upper part of the image forming apparatus main body 12. ing. For example, a one-stage sheet feeding unit 18 is disposed below the image forming apparatus main body 12.

  The paper feed unit 18 includes a paper feed unit main body 20 and a paper feed cassette 22 in which recording paper is stored. A feed roll 24 that feeds recording paper from the paper feed cassette 22 and a retard roll 26 that sprinkles the supplied recording paper one by one are arranged in the upper part near the rear end of the paper feed cassette 22.

  The conveyance path 28 is a path for recording paper from the feed roll 24 to the discharge port 30 through the guide member 29, and this conveyance path 28 is near the back side (right side surface in FIG. 1) of the image forming apparatus main body 12. Thus, the sheet feeding unit 18 and the fixing device 90 described later are formed substantially vertically. A secondary transfer roll 80 and a secondary transfer backup roll 72, which will be described later, are disposed on the upstream side of the fixing device 90 in the conveyance path 28, and a resist is provided on the upstream side of the secondary transfer roll 80 and the secondary transfer backup roll 72. A roll 32 is arranged. In addition, a discharge roll 34 is disposed in the vicinity of the discharge port 30 of the conveyance path 28.

  Accordingly, the recording paper fed from the paper feed cassette 22 of the paper feeding unit 18 by the feed roll 24 is turned by the retard roll 26 and only the uppermost recording paper is guided to the transport path 28. Then, the toner image is temporarily stopped by the registration roll 32, and the toner image is transferred by passing between the secondary transfer roll 80 and the secondary transfer backup roll 72 at a timing. The transferred toner image is fixed by the fixing device 90, and is discharged from the discharge port 30 to the discharge portion 36 provided at the upper part of the opening / closing cover 16 by the discharge roll 34. The discharge portion 36 has a low discharge port portion and is inclined so as to gradually become higher in the front direction (left direction in FIG. 1).

  In the image forming apparatus main body 12, for example, a rotary developing device 38 is disposed at a substantially central portion, and on the front side (left side in FIG. 1) of the rotary developing device 38, control for controlling each part constituting the image forming apparatus 10 is performed. Part 39 is arranged. The rotary developing device 38 includes developing units 42A to 42D that respectively form toner images of four colors of yellow, magenta, cyan, and black in the rotating body 40, and rotate counterclockwise (in FIG. It is designed to rotate counterclockwise. Each of the developing units 42A to 42D has developing rolls 46A to 46D, and is pressed in the normal direction of the rotating body 40 by elastic bodies 48A to 48D such as coil springs.

  The rotary developing device 38 is arranged so that an image carrier 50 made of, for example, a photosensitive member comes into contact therewith, and the developing rolls 46 </ b> A to 46 </ b> D are not in contact with the image carrier 50 and have one outer periphery. The portion is exposed from the opening 98 so as to protrude, for example, 2 mm from the outer periphery of the rotating body 40 in the radial direction. Further, tracking rolls (not shown) having diameters slightly larger than the diameters of the developing rolls 46A to 46D are provided at both ends of the developing rolls 46A to 46D so as to rotate coaxially with the developing rolls 46A to 46D. Yes.

  That is, the developing rolls 46A to 46D of the developing units 42A to 42D are arranged on the outer periphery of the rotating body 40 at intervals of 90 ° around the rotating shaft 44, and the tracking rolls of the developing rolls 46A to 46D serve as the image carrier 50. Each of the latent images on the image carrier 50 is in contact with flanges (not shown) provided at both ends of the image bearing member 50, forming a predetermined gap between the developing rolls 46A to 46D and the image carrier 50. The toner is developed with the toner.

  Below the image carrier 50, a charging roll 52 is provided as a charging member that uniformly charges the surface of the image carrier 50. The image carrier 50 is in contact with an image carrier cleaner 54 on the upstream side of the charging roller 52 in the rotational direction of the image carrier 50. The image carrier cleaner 54 includes, for example, a cleaning blade 56 that scrapes waste toner remaining on the image carrier 50 after primary transfer, and a toner collection bottle 58 that collects waste toner scraped off by the cleaning blade 56. Yes. For example, a rib or the like is formed on the back side (right side in FIG. 1) of the toner collection bottle 58 so as to form a part of the conveyance path 28 together with the guide member 29.

  Below the rotary developing device 38, an exposure device 60 for writing a latent image on the image carrier 50 charged by the charging roll 52 with a light beam such as a laser beam is disposed. Above the rotary developing device 38, an intermediate transfer device 62 is provided that conveys a toner image visualized by the rotary developing device 38 from a primary transfer portion described later to a secondary transfer position A.

  The intermediate transfer device 62 includes an intermediate transfer belt 64 as an intermediate transfer member, a primary transfer roll 66, a wrap-in roll 68, a wrap-out roll 70, a secondary transfer backup roll 72, a scraper backup roll 74, and a brush backup roll 76. ing. The intermediate transfer belt 64 has elasticity and is stretched substantially flat so as to have a long side and a short side above the rotary developing device 38.

  The long side on the upper surface side of the intermediate transfer belt 64 is stretched so as to be substantially parallel to, for example, the discharge unit 36 provided on the upper portion of the image forming apparatus main body 12. The intermediate transfer belt 64 has an image carrier between a wrap-in roll 68 disposed upstream of the primary transfer roll 66 below the long side and a wrap-out roll 70 disposed downstream of the primary transfer roll 66. 50 has a primary transfer portion (image carrier wrap region) that abuts in a lap shape, is wound around the image carrier 50 by a predetermined range, and is driven by the rotation of the image carrier 50.

  With such a configuration, the intermediate transfer belt 64 is primarily transferred by the primary transfer roll 66 after the toner image on the image carrier 50 is primarily transferred, for example, in the order of yellow, magenta, cyan, and black. The toner image is conveyed toward a secondary transfer roll 80 described later. At this time, the wrap-in roll 68 and the wrap-out roll 70 are separated from the image carrier 50.

  Further, a flat surface portion (short side) is formed on the back side (right side surface in FIG. 1) of the intermediate transfer belt 64 by a wrap-out roll 70 and a secondary transfer backup roll 72, and this flat surface portion is subjected to secondary transfer. It is configured to face the conveyance path 28 as a part. In the secondary transfer unit, the wrap-out roll 70 is arranged so that the intermediate transfer belt 64 and the conveyance path 28 are at an angle of 12 °, for example.

  The scraper backup roll 74 assists the scraper 84 described later to scrape waste toner remaining on the intermediate transfer belt 64 after the secondary transfer, and the brush backup roll 76 on the intermediate transfer belt 64 after the secondary transfer. A brush roll 86 described later assists in scraping off the remaining waste toner.

  A secondary transfer roll 80 is opposed to the secondary transfer backup roll 72 of the intermediate transfer device 62 with the conveyance path 28 interposed therebetween. That is, a secondary transfer position A in the secondary transfer portion is between the secondary transfer roll 80 and the secondary transfer backup roll 72, and the secondary transfer roll 80 is assisted by the secondary transfer backup roll 72. The toner image primarily transferred onto the intermediate transfer belt 64 is secondarily transferred onto the recording paper at the secondary transfer position A.

  Here, the secondary transfer roll 80 is separated from the intermediate transfer belt 64 while the intermediate transfer belt 64 rotates three times, that is, while the three color toner images of yellow, magenta, and cyan are conveyed. When the image is transferred, it is configured to contact the intermediate transfer belt 64. A predetermined developing bias voltage is generated between the secondary transfer roll 80 and the secondary transfer backup roll 72. For example, when the secondary transfer roll 80 is set to a high voltage, The next transfer backup roll 72 is connected to a ground (GND) or the like.

  Between the secondary transfer roll 80 and the guide member 29, for example, a detection device 81 such as a reflective photosensor is disposed so as to face the secondary transfer portion of the intermediate transfer belt 64. The detection device 81 irradiates the intermediate transfer belt 64 with irradiation light, and receives reflected light that is formed on the intermediate transfer belt 64 and changes according to, for example, a reference toner image for toner concentration detection. The density of the reference toner image formed on the transfer belt 64 is detected.

  When the density of the reference toner image is detected by the detection device 81, the control unit 39 controls the charging voltage of the charging roll 52, the exposure light amount of the exposure device 60, the development bias voltage, and the like according to the detected toner density, The toner density on the intermediate transfer belt 64 is adjusted. Further, the detection device 81 is configured so that the recording paper conveyed by the guidance of the guide member 29 comes into sliding contact, and guides the recording paper toward the secondary transfer position A. As described above, the detection device 81 forms a part of the transport path 28.

  An intermediate transfer body cleaner 82 is provided in contact with the end of the intermediate transfer belt 64 opposite to the image carrier 50. The intermediate transfer member cleaner 82 includes, for example, a scraper 84 that scrapes and cleans waste toner remaining on the intermediate transfer belt 64 after secondary transfer, a brush roll 86 that scrapes off waste toner remaining after cleaning by the scraper 84, and a scraper. 84 and a toner collecting bottle 88 that collects the waste toner scraped off by the brush roll 86.

  The scraper 84 is made of, for example, a stainless steel thin plate, and is applied with a voltage having a polarity opposite to that of the toner. The brush roll 86 is made of, for example, an acrylic brush that has been subjected to a conductive treatment. Further, while the intermediate transfer belt 64 conveys the toner image, the scraper 84 and the brush roll 86 are separated from the intermediate transfer belt 64, and at a predetermined timing, they are integrated with the intermediate transfer belt 64. It is configured to touch.

  A fixing device 90 is disposed above the secondary transfer position A. The fixing device 90 includes a heating roll 92 and a pressure roll 94, and fixes the toner image secondarily transferred to the recording sheet by the secondary transfer roll 80 and the secondary transfer backup roll 72 on the recording sheet. It is conveyed toward the discharge roll 34.

  The image forming unit 96 is a unit in which an intermediate transfer device 62, an image carrier 50, a charging roll 52, an image carrier cleaner 54, and an intermediate transfer body cleaner 82 are integrated. That is, in the image forming unit 96, the intermediate transfer device 62 having the intermediate transfer belt 64 extends on the front side of the image carrier 50, and further, an intermediate transfer member cleaner 82 is disposed at the end. An image carrier cleaner 54 is disposed below the back side of the image carrier 50.

  As described above, in the image forming unit 96, the direction in which the intermediate transfer belt 64 extends and the direction in which the image carrier cleaner 54 is disposed exceed 90 ° and less than 180 ° with the secondary transfer position A as the apex. It is bent so as to surround the rotary developing device 38. The image forming unit 96 is disposed immediately below the discharge portion 36 of the opening / closing cover 16 and is detachable from the image forming apparatus main body 12. The image forming unit 96 is attached / detached by opening the opening / closing cover 16. It has become.

  Further, the above-described charging roll 52 is provided with a cleaning member 100. As shown in FIG. 2, the cleaning member 100 is provided with an elongated columnar metal shaft 102 having a rectangular shape (for example, substantially square shape) in a side view, and a holding member 106 on the upper surface of the shaft 102. And a brush 104. The brush 104 is configured by, for example, a raising member made of a blend of polyethylene terephthalate (PET) fibers and 6-6 nylon (trademark) fibers implanted in the holding member 106, and the holding member 106. Is attached to the upper surface of the shaft 102 with an adhesive or the like.

  As shown in FIGS. 2 to 4, in the cleaning member 100, both end portions 102 </ b> A of the shaft 102 to which the brush 104 (holding member 106) is not attached are formed in a frame 108 provided in the image forming apparatus main body 12. When the E-ring (not shown) is fitted into a groove portion (not shown) formed in one end portion 102A, the E-ring (not shown) is inserted into the slot 110. It is designed to prevent falling out of The frame 108 is also a frame that rotatably supports the charging roll 52.

  The long hole 110 is formed in a rectangular shape (for example, a substantially rectangular shape) in which the direction parallel to the arrow direction shown in FIGS. 3 and 4 is longer than the height (thickness) H (see FIG. 2) of the shaft 102. The edge portion 110A on the roll 52 side and the upper surface 102B of the end portion 102A of the shaft 102 facing the charging roll 52 are flat surfaces.

  In addition, a slight clearance is provided between the edge portions 110B and 110C of the long hole 110 and both side surfaces 102C of the end portion 102A of the shaft 102 in the rotation direction of the charging roll 52 (the direction of arrow D in FIG. 2). (See FIGS. 5 and 6). Accordingly, the cleaning member 100 is configured to be slightly movable in the rotation direction as the charging roll 52 rotates, and the hair tip (tip) region of the brush 104 that contacts the charging roll 52 (FIG. 2). (Region in the direction of arrow D) is widened.

  The cleaning member 100 is moved up and down by the contact / separation mechanism 112. That is, as shown in FIGS. 5 and 6, the arm 114 of the contact / separation mechanism 112 has the lower surface 102 </ b> D of the both ends 102 </ b> A of the shaft 102 projecting outward from the long hole 110 upward (on the charging roll 52 side). By pressing toward the brush 104, the brush 104 comes into contact with the charging roll 52 with a predetermined pressing force.

  When the brush 104 is separated from the charging roll 52, the driving force to the arm 114 may be cut off, so that the cleaning member 100 is separated from the charging roll 52 by its own weight. That is, the contact / separation mechanism 112 includes only a mechanism for raising the arm 114, and the structure thereof is simplified.

  Next, the operation of the image forming apparatus 10 configured as described above will be described. When an image forming signal is sent to the image forming apparatus 10, the image carrier 50 is uniformly charged by the charging roll 52, and the charged image carrier 50 receives light from the exposure device 60 based on the image signal. Emitted. The light beam from the exposure device 60 exposes the surface of the image carrier 50, whereby a latent image is formed.

  The latent image of the image carrier 50 formed by the exposure device 60 is developed with yellow, magenta, cyan, and black toner images by the rotary developing device 38 and is superimposed on the intermediate transfer belt 64 and is primarily transferred. In the primary transfer, waste toner remaining on the image carrier 50 is scraped off and collected by the image carrier cleaner 54.

  On the other hand, the recording paper stored in the paper feed cassette 22 by a paper feed signal or the like is sent out by the feed roll 24, is turned by the retard roll 26, is guided to the transport path 28, and is temporarily stopped by the registration roll 32. And is conveyed toward the guide member 29. The guide member 29 guides the recording sheet to the detection device 81 and guides it to the secondary transfer position A when an image is formed on the recording sheet under the control of the control unit 39.

  When the recording sheet is guided to the secondary transfer position A, the toner image primarily transferred to the intermediate transfer belt 64 is secondarily transferred to the recording sheet by the secondary transfer roll 80 and the secondary transfer backup roll 72. . After the secondary transfer, waste toner remaining on the intermediate transfer belt 64 is scraped off and collected by the intermediate transfer body cleaner 82.

  The recording paper to which the toner image has been transferred is guided to the fixing device 90, and the toner image is fixed by the thermal pressure of the heating roll 92 and the pressure roll 94. The recording sheet on which the toner image is fixed is discharged from the discharge port 30 to the discharge unit 36 by the discharge roll 34.

  On the other hand, the surface of the charging roll 52 is cleaned by the brush 104 of the cleaning member 100. That is, as shown in FIGS. 3 and 5, the arm 114 is lifted by the contact / separation mechanism 112, and the shaft 102 is lifted until the upper surface 102 </ b> B at the end 102 </ b> A contacts the edge 110 </ b> A of the long hole 110. .

  At this time, since the upper surface 102B of the shaft 102 and the edge portion 110A of the long hole 110 are both flat surfaces, they both come into contact with each other with high accuracy. Therefore, the position and angle of the brush 104 with respect to the surface of the charging roll 52 are accurately positioned, and thus the surface of the charging roll 52 can be suitably cleaned.

  In addition, since both the long hole 110 and the shaft 102 are formed in a rectangular shape, the brush 104 is prevented from rotating (rotating) even if the charging roll 52 rotates (the slight amount existing in the rotating direction of the charging roll 52). Only moves by the amount of clearance). Therefore, the cleaning performance of the cleaning member 100 with respect to the charging roll 52 can be stabilized. In addition, since the position of the rectangular shaft 102 may be regulated by the rectangular elongated hole 110 as described above, it is preferable in terms of structure and cost.

  Further, in the shaft 102 and the long hole 110, as described above, between the rotation direction of the charging roll 52, that is, between the both side surfaces 102C of the end portion 102A of the shaft 102 and the edge portions 110B and 110C of the long hole 110. However, since the clearance is provided slightly, the brush 104 can be rotated (moved) by this clearance. For this reason, the area | region of the hair | bristle tip (tip | tip) of the brush 104 contacted with the charging roll 52 can be expanded, and the replacement time by the cleaning performance of the cleaning member 100 falling can be extended. That is, the life of the cleaning member 100 can be extended.

  Further, since the shaft 102 is made of metal, the shape of the shaft 102 can be accurately maintained even when the number of times that the upper surface 102B abuts on the edge portion 112A of the elongated hole 110 increases. Moreover, since it is metal, even if it reduces the shaft 102, the intensity | strength can fully be ensured and the bending of the center part of the shaft 102 can be suppressed. Therefore, the contact state of the brush 104 with respect to the charging roll 52 can be always suitably maintained. The shaft 102 is preferably formed entirely of metal, but the present invention is not limited to this, and it is sufficient that at least both end portions 102A inserted into the long holes 112 are formed of metal.

  As described above, the cleaning member 100 according to the present invention can suitably clean the charging roll 52. That is, the cleaning performance of the cleaning member 100 with respect to the charging roll 52 can be stabilized. In addition, even if the both ends of the shaft are formed in a substantially circular shape when viewed from the side, when the shaft is inserted into the elongated hole 110 and brought into contact with the charging roll 52, the rotation preventing member (not shown) It goes without saying that the same effect as described above can be obtained as long as the (omitted) is attached to the end.

Schematic side view of image forming apparatus Schematic perspective view of cleaning member Schematic perspective view showing a state where the cleaning member is in contact with the charging roll Schematic perspective view showing a state in which the cleaning member is separated from the charging roll Schematic side view showing a state in which the cleaning member is brought into contact with the charging roll by the contact / separation mechanism Schematic side view showing a state in which the cleaning member is separated from the charging roll by the contact / separation mechanism

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 38 Rotary developing device 50 Image carrier 52 Charging roll (charging member)
100 Cleaning member 102 Shaft 104 Brush 106 Holding member 108 Frame 110 Long hole 112 Contact / separation mechanism 114 Arm

Claims (4)

A charging member that contacts the rotating image carrier while rotating and charges the image carrier;
A cleaning member comprising a brush for cleaning the surface of the charging member, and a shaft to which the brush is attached;
A frame that has an elongated hole through which an end of the shaft of the cleaning member is inserted, and that rotatably supports the charging member;
A contact / separation mechanism for contacting and separating the cleaning member with respect to the charging member;
With
An image forming apparatus, wherein a side edge of the elongated hole on the charging member side is formed in a flat shape, and a surface of the end portion of the shaft facing the charging member is formed in a flat shape.   The image forming apparatus according to claim 1, wherein at least an end portion of the shaft inserted through the elongated hole is formed of metal.   3. The image forming apparatus according to claim 1, wherein a predetermined clearance is provided between an end portion of the shaft and the elongated hole in a rotation direction of the charging member.   The contact / separation mechanism is configured to push up both end portions of the shaft to bring the brush into contact with the charging member, and to separate the brush from the charging member by the weight of the cleaning member. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus.

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