Patent Publication Number: US-11385574-B2

Title: Rotation device and image forming apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2020-167886 filed Oct. 2, 2020. 
     BACKGROUND 
     (i) Technical Field 
     The present disclosure relates to a rotation device and an image forming apparatus. 
     (ii) Related Art 
     JP-A-58-005769 discloses a transfer device for transferring an image on an image carrier. The transfer device includes a transferred material transporting unit, a gripper piece, and a switch member. The transferred material transporting unit moves a transferred material in an endless manner along a circulating movement path. The gripper piece is attached to the transporting unit. The gripper piece is pivotally supported by a rotating shaft. The gripper piece rotates relative to a base member. The gripper piece holds a leading end side of the transferred material. The switch member is attached to a base member side. In order to detect whether the transferred material is in the gripper, a part of a switch member position in the gripper piece is cut out. 
     SUMMARY 
     Consider a rotation device including a rotary body having a recess in an outer peripheral surface thereof, and a brush that comes into contact with the outer peripheral surface of the rotary body to remove foreign matter adhering to the outer peripheral surface. If this rotation device has a configuration that the brush is in contact with the outer peripheral surface of the rotary body in a state in which the rotation of the rotary body is stopped, settling of the brush may occur. 
     Aspects of non-limiting embodiments of the present disclosure relate to preventing settling of a brush in a state in which rotation of a rotary body is stopped, as compared to a configuration in which the brush is in contact with an outer peripheral surface of the rotary body. 
     Aspects of certain non-limiting embodiments of the present disclosure address the above advantages and/or other advantages not described above. However, aspects of the non-limiting embodiments are not required to address the advantages described above, and aspects of the non-limiting embodiments of the present disclosure may not address advantages described above. 
     According to an aspect of the present disclosure, there is provided a rotation device including: a rotary body having a recess in an outer peripheral surface thereof; and a brush configured to come into contact with the outer peripheral surface of the rotary body to remove a foreign matter adhering to the outer peripheral surface, in which the brush is separated from the outer peripheral surface of the rotary body in a state where rotation of the rotary body is stopped. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiment(s) of the present disclosure will be described in detail based on the following figures, wherein: 
         FIG. 1  is a schematic diagram showing a configuration of an image forming apparatus according to a first exemplary embodiment; 
         FIG. 2  is a perspective view showing a configuration around a transfer cylinder according to the first exemplary embodiment; 
         FIG. 3  is a perspective view showing grippers according to the first exemplary embodiment; 
         FIG. 4  is a schematic diagram showing a configuration of a cleaning device and the transfer cylinder according to the first exemplary embodiment; 
         FIG. 5  is a schematic diagram showing a brush and a flicker according to the first exemplary embodiment; 
         FIG. 6  is a schematic diagram showing a state in which a recess of the transfer cylinder opposes the brush in the cleaning device according to the first exemplary embodiment; 
         FIG. 7  is a schematic diagram showing a configuration of an image forming apparatus according to a second exemplary embodiment; 
         FIG. 8  is a schematic diagram showing a configuration of a cleaning device according to a modification; and 
         FIG. 9  is a schematic diagram showing a state where a body of the cleaning device according to the modification is located at a separated position. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, an example of an exemplary embodiment according to the present disclosure will be described with reference to the accompanying drawings. 
     First Exemplary Embodiment 
     Image Forming Apparatus  10   
     A configuration of an image forming apparatus  10  according to the first exemplary embodiment will be described.  FIG. 1  is a schematic view showing the configuration of the image forming apparatus  10  according to the present exemplary embodiment. In the drawings, an arrow H indicates an apparatus height direction which is a vertical direction, an arrow W indicates an apparatus width direction which is one of horizontal directions, and an arrow D indicates an apparatus depth direction which is another one of the horizontal directions (a front to rear direction of the apparatus). Dimensional ratios in the H direction, the W direction, and the D direction of respective elements shown in the respective drawings may be different from actual dimensional ratios. 
     The image forming apparatus  10  shown in  FIG. 1  is an inkjet image forming apparatus that forms an ink image (an example of an image) on a recording medium P. Specifically, the image forming apparatus  10  includes an image forming unit  14 , a transport mechanism  12 , and an opposing cylinder  250 . Hereinafter, each of elements (that is, the image forming unit  14 , the transport mechanism  12 , and the opposing cylinder  250 ) of the image forming apparatus  10  will be described. 
     Image Forming Unit  14   
     The image forming unit  14  has a function of forming an ink image on a transported recording medium P. Specifically, as shown in  FIG. 1 , the image forming unit  14  includes ejection units  14 Y,  14 M,  14 C, and  14 K (hereinafter, referred to as  14 Y to  14 K) that eject ink to predetermined ejection positions. 
     The ejection units  14 Y to  14 K are disposed in the above order toward a downstream side in a transport direction of the recording medium P. The ejection units  14 Y to  14 K are elongated along a width direction of the recording medium P. The width direction of the recording medium P is a direction that intersects the transport direction (specifically, a direction which is perpendicular to the transport direction), and is a direction extending along the front to rear direction of the apparatus. 
     In the image forming unit  14 , the ejection units  14 Y to  14 K eject ink droplets onto the recording medium P, which is transported by the transport mechanism  12 , using a known technique such as a thermal technique or a piezoelectric technique to form the ink image on the recording medium P. 
     Transport Mechanism  12   
     The transport mechanism  12  shown in  FIG. 1  is a mechanism that transports the recording medium P. As shown in  FIGS. 1 and 2 , the transport mechanism  12  includes a pair of chains  22 , and the grippers  24 . In  FIG. 1 , one of the chains  22  is shown, and the chain  22  and the grippers  24  are shown in a simplified manner. 
     As shown in  FIG. 1 , each of the chains  22  is formed in an annular shape. As shown in  FIG. 2 , the chains  22  are arranged at an interval in the apparatus depth direction (that is, a D direction in  FIG. 2 ). Each of the chains  22  is wound on a respective one of the sprockets  25  and a respective one of the sprockets  37  (see  FIG. 1 ). The sprockets  25  are provided at both ends, in the axial direction, of the opposing cylinder  250 . The opposing cylinder  250  and the pair of sprockets  25  are integrally rotationally driven in a rotation direction B (a direction of the arrow B), and thereby the chain  22  circulates in a circulating direction C (a direction of the arrow C). 
     As shown in  FIG. 2 , an attachment member  23  to which grippers  24  are attached bridges between the chains  22  along the apparatus depth direction. The plural attachment members  23  are fixed to the pair of chains  22  at predetermined intervals along the circulating direction C of the chains  22 . 
     As shown in  FIG. 2 , the plural grippers  24  are attached to the attachment member  23  at predetermined intervals along the apparatus depth direction. The gripper  24  functions as a holder that holds a leading end portion of the recording medium P. Specifically, as shown in  FIG. 3 , the gripper  24  includes a pawl  24 A and a pawl base  24 B. The gripper  24  holds the recording medium P by sandwiching the leading end portion of the recording medium P between the pawl  24 A and the pawl base  24 B. In the gripper  24 , for example, the pawl  24 A is pressed against the pawl base  24 B by a spring, and the pawl  24 A is opened from and closed to the pawl base  24 B by the action of a cam. 
     In the transport mechanism  12 , as shown in  FIG. 3 , the grippers  24  hold the leading end portion of the recording medium P sent from an accommodating unit (not illustrated) that accommodates recording media P. The chains  22  circulate in the circulating direction C, so that the grippers  24  holding the leading end portion of the recording medium P transports the recording medium P and causes the recording medium P to pass through the ejection positions of the ejection units  14 Y to  14 K. Then, the ejection units  14 Y to  14 K eject the ink droplets onto the recording medium P passing through the ejection positions at timings when the recording medium P is at the ejection positions, thereby forming ink images. 
     Rotation Device  16   
     The rotation device  16  includes the opposing cylinder  250 , a driving unit  17 , a brake  18 , and a cleaning device  15 . The opposing cylinder  250  is an example of a rotary body. The brake  18  is an example of a separation mechanism and is also an example of a stop unit. The configuration of the brake  18  will be described later. 
     As shown in  FIG. 1 , the opposing cylinder  250  is a cylinder member opposing the ejection units  14 Y to  14 K. The opposing cylinder  250  is formed in a circular shape in a side view and has a recess  254  in an outer peripheral surface thereof. Grippers  24  and an attachment member  23 , which will be described later, are accommodated in the recess  254 . A specific configuration of the recess  254  will be described later. 
     As shown in  FIG. 2 , the pair of sprockets  25  is provided at both end portions, in an axial direction, of the opposing cylinder  250 . The sprockets  25  are disposed coaxially with the opposing cylinder  250 , and rotate integrally with the opposing cylinder  250 . The opposing cylinder  250  and the pair of sprockets  25  are rotationally driven by the driving unit  17  (for example, a motor; see  FIG. 1 ). Hereinafter, the axial direction of the opposing cylinder  250  may be simply referred to as an ‘axial direction’. 
     More specifically, as shown in  FIG. 4 , the opposing cylinder  250  includes a cylinder body  252  and an elastic layer  256 . The cylinder body  252  is made of a metal material such as stainless steel or aluminum. The elastic layer  256  is wound around an outer periphery of the cylinder body  252 . As the elastic layer  256 , for example, a rubber layer made of a foamed rubber is used. 
     Cleaning Device  15   
     The cleaning device  15  shown in  FIG. 4  is a device that cleans the outer peripheral surface of the opposing cylinder  250 . Specifically, the cleaning device  15  is a device that removes foreign matter adhering to the outer peripheral surface of the opposing cylinder  250 . As shown in  FIG. 4 , the cleaning device  15  includes a body  40 , a duct frame  60 , and a cleaning unit  70 . Examples of the foreign matter include ink droplets, and paper dust when the recording medium P is a sheet of paper. In the present exemplary embodiment, the outer peripheral surface of the opposing cylinder  250  is a surface of the elastic layer  256 . 
     Body  40  of Cleaning Device  15   
     As shown in  FIG. 4 , the body  40  includes a box-shaped housing  42 . The housing  42  is formed in a substantially rectangular parallelepiped shape and is elongated along the axial direction. The housing  42  has an opening  42 A that opens toward the opposing cylinder  250  (that is, opens rightward in  FIG. 4 ). 
     Duct Frame  60  and Cleaning Unit  70   
     As shown in  FIG. 4 , the duct frame  60  and the cleaning unit  70  are disposed inside the housing  42  of the body  40 . 
     The cleaning unit  70  includes a box-shaped housing  80 , a brush  72 , a flicker  74 , a transport auger  76 , and seal members  78  and  79 . The flicker  74  is an example of a contact member. 
     The housing  80  is formed in a substantially rectangular parallelepiped shape and is elongated along the axial direction. The housing  80  has an opening  82  that opens toward the opposing cylinder  250  (that is, opens rightward in  FIG. 4 ). 
     The brush  72  includes a shaft portion  72 A and a brush portion  72 B provided on an outer periphery of the shaft portion  72 A. The brush portion  72 B is disposed over the entire circumference of the shaft portion  72 A. The brush portion  72 B includes fibers that extend radially outward from the shaft portion  72 A. As the fibers, for example, resin fibers such as polyethylene terephthalate (PET) is used. A fiber diameter of the fiber is, for example, 2d (denier) or more and 15d (denier) or less. A fiber density is, for example, 10,000 fibers/inch 2  or more and 120,000 fibers/inch 2  or less. A part of the brush portion  72 B in the circumferential direction is a contact portion that comes into contact with the outer peripheral surface of the opposing cylinder  250 . 
     Specifically, the brush  72  is housed inside the housing  80 . The contact portion of the brush portion  72 B to the opposing cylinder  250  is exposed through the opening  82 . Then, the contact portion of the brush portion  72 B comes into contact with the outer peripheral surface of the opposing cylinder  250 . 
     The shaft portion  72 A of the brush  72  extends in the front to rear direction of the apparatus. Both end portions of the shaft portion  72 A in the axial direction are rotatably supported by the body  40  of the cleaning device  15 . The shaft portion  72 A of the brush  72  is driven by a driving unit (not illustrated), so that the brush  72  rotates in a forward direction with respect to a rotation direction of the opposing cylinder  250 . That is, while the opposing cylinder  250  rotates in a counterclockwise direction in  FIG. 4 , the brush  72  rotates in a clockwise direction in  FIG. 4 . A circumferential speed ratio of the brush  72  to the opposing cylinder  250  is more than 1. That is, the circumferential speed of the brush  72  is faster than the circumferential speed of the opposing cylinder  250 . In the present exemplary embodiment, the circumferential speed ratio of the brush  72  to the opposing cylinder  250  is in a range of, for example, 1 and 2.5 (inclusive). The circumferential speed of the brush  72  is a circumferential speed of a tip of a part that does not penetrate into the opposing cylinder  250 . 
     In the brush  72 , each part of the brush portion  72 B in the circumferential direction repeatedly comes into contact with and separates from the outer peripheral surface of the opposing cylinder  250  as the brush portion  72 B rotates. Then, the brush portion  72 B elastically deformed by coming into contact with the outer peripheral surface of the opposing cylinder  250  elastically restores, to thereby repel the foreign matter adhering to the outer peripheral surface of the opposing cylinder  250 , and physically remove the foreign matter from the outer peripheral surface. 
     The brush  72  may remove the foreign matter from the outer peripheral surface of the opposing cylinder  250  by electrostatic force in addition to or instead of the physical removal described above. 
     The flicker  74  is disposed below the brush  72  and is in contact with the brush portion  72 B. The flicker  74  is formed in a rod shape and has a circular cross section. The flicker  74  contacts with the rotating brush  72  to drop the foreign matter adhering to the brush  72 . The dropped foreign matter is accommodated inside the housing  80  and accumulates on a bottom surface inside the housing  80 . 
     In the present exemplary embodiment, as shown in  FIG. 5 , KA&gt;KB, where KA is a penetration depth of the brush  72  into the flicker  74 , and KB is a penetration depth of the brush  72  into the opposing cylinder  250 . The penetration depth KA is a length by which the brush  72  and the flicker  74  overlap each other in a radial direction of the brush  72 . The penetration depth KB is a length by which the brush  72  and the opposing cylinder  250  overlap each other in a radial direction of the brush  72 . In the present exemplary embodiment, the penetration depth KA is, for example, 0.5 mm or more and 3.0 mm or less, and the penetration depth KB is, for example, 0.3 mm or more and 2.8 mm or less. 
     In the present exemplary embodiment, SL&gt;SA, where SA is a contact width between the brush  72  and the flicker  74  as viewed in the axial direction, and SL is a contact width between the brush  72  and the outer peripheral surface of the opposing cylinder  250  as viewed in the axial direction. Therefore, the number of contacting filaments of the brush  72  that are in contact with the outer peripheral surface of the opposing cylinder  250  is larger than the number of contacting filaments of the brush  72  that are in contact with the flicker  74 . The number of contacting filaments can also be said to be the number of deformed filaments of the brush  72 . The contact width SA is, for example, 3 mm or more and 15 mm or less, and the contact width SL is, for example, 5 mm or more and 20 mm or less. The length of the fibers of the brush portion  72 B (that is, the length in the radial direction) is, for example, 4 mm or more and 10 mm or less, and the distance between the shaft portion  72 A of the brush  72  and the opposing cylinder  250  is 1.2 mm or more and 9.7 mm or less. 
     As shown in  FIG. 4 , the transport auger  76  is disposed on the bottom surface inside the housing  80 . The transport auger  76  includes a shaft portion  76 A and a blade portion  76 B having a spiral shape. The blade portion  76 B is disposed on the outer periphery of the shaft portion  76 A. 
     The shaft portion  76 A of the transport auger  76  extends in the front to rear direction of the image forming apparatus  10 . Both end portions of the shaft portion  76 A in the axial direction are rotatably supported by the body  40 . In the transport auger  76 , as the shaft portion  76 A rotates, the blade portion  76 B rotates to transport the foreign matter dropped onto the bottom surface inside the housing  80  rearward along the axial direction of the brush  72 , and discharge the foreign matter from a rear end of the housing  80  through a discharge pipe (not illustrated). 
     The seal members  78  and  79  have a function of preventing the foreign matter accommodated inside the housing  80  from leaking to an outside of the housing  80  through the opening  82  of the housing  80 . Each of the seal members  78  and  79  is formed of, for example, a flexible and deformable film material. 
     As shown in  FIG. 4 , the seal member  78  is attached to the upper edge  83  provided on an upper side of the opening portion  82  in the housing  80 . Specifically, the seal member  78  extends obliquely downward from the upper edge  83  toward the opposing cylinder  250  (that is, the right side in  FIG. 4 ), and a tip portion of the seal member  78  is in contact with the outer peripheral surface of the opposing cylinder  250 . 
     The seal member  79  is attached to the lower edge  87  provided on a lower side of the opening portion  82  of the housing  80 . Specifically, the seal member  79  extends upward from the lower edge  87 , and a tip portion of the seal member  79  is in contact with the flicker  74 . 
     The duct frame  60  is a frame that is an element constituting ducts  91  and  92 . In the present exemplary embodiment, the ducts  91  and  92  are defined by the duct frame  60  and the housing  80  of the cleaning unit  70 . The duct  91  is disposed above the brush  72  and above the housing  80 . 
     The duct  91  has a suction port  91 A that opens toward the opposing cylinder  250 . As shown in  FIG. 6 , when the opposing cylinder  250  is at a rotation position where the recess  254  of the opposing cylinder  250  opposes the brush  72  (that is, a left side in  FIG. 6 ), the suction port  91 A opposes the recess  254 . That is, the suction port  91 A opens at a position above the brush  72 . The duct  91  extends in the front to rear direction. 
     As shown in  FIG. 4 , the duct  92  is disposed below the brush  72  and below the housing  80 . The duct  92  has a suction port  92 A that opens toward the opposing cylinder  250 . As shown in  FIG. 6 , when the opposing cylinder  250  is at the rotation position where the recess  254  of the opposing cylinder  250  opposes the brush  72  (that is, the left side in  FIG. 6 ), the suction port  92 A opposes the recess  254 . That is, the suction port  92 A opens at a position below the brush  72 . The duct  92  extends in the front to rear direction. 
     The duct  91  and the duct  92  are connected to each other on the rear side, and a tube (not illustrated) is connected to a coupling portion between the duct  91  and the duct  92 . A blower (not illustrated) is provided in the tube. When the blower is driven, air containing the foreign matter is taken into the duct  91  through the suction port  91 A and is taken into the duct  92  through the suction port  92 A. The air taken into the ducts  91  and  92  flows in the ducts  91  and  92  to the rear side. The air flowing through the ducts  91  and  92  merge with each other, and is discharged through the tube. 
     Relationship Between Respective Elements of Cleaning Device  15  and Recess  254  of Opposing Cylinder  250   
     As shown in  FIG. 6 , one recess  254  of the opposing cylinder  250  is provided in a part of the outer peripheral surface of the opposing cylinder  250  in the circumferential direction. The recess  254  is elongated along the axial direction of the opposing cylinder  250  and has a depth along the radial direction of the opposing cylinder  250 . 
     An opening width  254 L (see  FIG. 6 ) of the recess  254  as viewed in the axial direction is wider than a contact width SL (see  FIG. 5 ) between the brush  72  and the outer peripheral surface of the opposing cylinder  250  as viewed in the axial direction. A depth  254 D (see  FIG. 6 ) of the recess  254  is larger than the penetration depth KB (see  FIG. 5 ) of the brush  72  into the opposing cylinder  250 . Therefore, in a state in which the brush  72  opposes the recess  254 , the brush  72  is not in contact with the opposing cylinder  250 , and is separated from the outer peripheral surface of the opposing cylinder  250 . Further, the opening width  254 L of the recess  254  is larger than the outer diameter of the brush  72 , larger than an opening width  80 L of the opening  82  of the housing  80  as viewed in the axial direction, and larger than a width  60 L between a tip of an upper wall of the duct frame  60  and a tip of a lower wall of the duct frame  60  as viewed in the axial direction. The opening width  254 L, the contact width SL, the opening width  80 L, and the width  60 L are widths along the circumferential direction of the opposing cylinder  250 . 
     Brake  18   
     For example, the brake  18  illustrated in  FIG. 1  stops the rotation of the opposing cylinder  250  by holding a rotating shaft of the opposing cylinder  250 . Specifically, when the opposing cylinder  250  transitions from a mode in which the opposing cylinder  250  rotates (hereinafter, referred to as a “rotation mode”) to a mode in which the rotation of the opposing cylinder  250  stops (hereinafter, referred to as a “stop mode”), the brake  18  stops the rotation of the opposing cylinder  250  at a position (a position shown in  FIG. 6 ) at which the recess  254  opposes the brush  72 . 
     Examples of the rotation mode include a state in which an image formation process of forming an ink image on the recording medium P is executed. Examples of the stop mode include (i) a standby state in which the image formation process is not executed and (ii) a state in which an operation of the image forming apparatus  10  is stopped when a power of the image forming apparatus  10  is turned off. 
     In the present exemplary embodiment, the brake  18  stops the rotation of the opposing cylinder  250  at the position where the recess  254  opposes the brush  72 , to thereby separate the brush  72  from the outer peripheral surface of the opposing cylinder  250  in a state where the rotation of the opposing cylinder  250  is stopped. A detector such as an optical sensor detects if the recess  254  is at the position where the recess  254  opposes the brush  72 . 
     Effect of the Present Exemplary Embodiment 
     According to the present exemplary embodiment, as described above, when the opposing cylinder  250  transitions from the rotation mode to the stop mode, the brake  18  stops the rotation of the opposing cylinder  250  at the position where the recess  254  opposes the brush  72 . As a result, the brake  18  separates the brush  72  from the outer peripheral surface of the opposing cylinder  250  in a state where the rotation of the opposing cylinder  250  is stopped. 
     In the present exemplary embodiment, the flicker  74  comes into contact with the rotating brush  72  to drop the foreign matter adhering to the brush  72 . 
     In the present exemplary embodiment, as shown in  FIG. 5 , KA&gt;KB, where KA is the penetration depth of the brush  72  into the flicker  74 , and KB is the penetration depth of the brush  72  into the opposing cylinder  250 . 
     In the present exemplary embodiment, SL&gt;SA, where SA is the contact width between the brush  72  and the flicker  74  as viewed in the axial direction, and SL is the contact width between the brush  72  and the outer peripheral surface of the opposing cylinder  250  as viewed in the axial direction. Here, since the brush  72  can be separated from the outer peripheral surface of the opposing cylinder  250 , it is possible to prevent the settling of the brush  72  due to the brush  72  contacting with the opposing cylinder  250 . 
     Second Exemplary Embodiment 
     Image Forming Apparatus  200   
     In the first exemplary embodiment, the image forming apparatus  10  is the inkjet image forming apparatus that forms an image on the recording medium P using the ink. The present disclosure is not limited thereto. As an example of the image forming apparatus, for example, an electrophotographic image forming apparatus may be used, and any device that forms an image may be used. In the second exemplary embodiment, the electrophotographic image forming apparatus  200  will be described.  FIG. 7  is a schematic diagram showing a configuration of an image forming apparatus  200  according to the present exemplary embodiment. Parts having same functions as those in the first exemplary embodiment are denoted by the same reference numerals, and description thereof is omitted as appropriate. 
     Image Forming Unit  214   
     The image forming apparatus  200  includes an image forming unit  214  instead of the image forming unit  14 . The image forming unit  214  has a function of forming a toner image (an example of an image) on a recording medium P by an electrophotographic technique. Specifically, as shown in  FIG. 7 , the image forming unit  214  includes toner image forming units  222  that form toner images, and a transfer device  217  that transfers the toner images formed by the toner image forming units  222  to the recording medium P. 
     Toner Image Forming Unit  222   
     The toner image forming units  222  shown in  FIG. 7  are provided so as to form toner images of respective colors. In the present exemplary embodiment, the toner image forming unit  222  of four colors of yellow (Y), magenta (M), cyan (C), and black (K) are provided. (Y), (M), (C), and (K) shown in  FIG. 7  represent components corresponding to the respective colors described above. 
     Since the toner image forming units  222  of the respective colors have similar configuration except for a toner used therein, the reference numerals are given to the respective elements of the toner image forming unit  222 (K) in  FIG. 7  as a representative of the toner image forming units  222  of the respective colors. 
     Specifically, the toner image forming unit  222  of each color includes a photoconductor  224  that rotates in one direction (for example, a counterclockwise direction in  FIG. 7 ). The toner image forming unit  222  of each color includes a charging unit  223 , an exposure device  240 , and a developing device  238 . 
     In the toner image forming unit  222  of each color, the charging unit  223  charges the photoconductor  224 . Further, the exposure device  240  exposes the photoconductor  224  charged by the charging unit  223  to form an electrostatic latent image on the photoconductor  224 . The developing device  238  develops the electrostatic latent image formed on the photoconductor  224  by the exposure device  240 , to form a toner image. 
     Transfer Device  217   
     The transfer device  217  shown in  FIG. 7  is a device that transfers the toner image formed by the toner image forming unit  222  to the recording medium P. Specifically, the transfer device  217  primarily transfers the toner images of the photoconductors  224  of the respective colors onto a transfer belt  213  (as an intermediate transfer body) in a superimposed manner, and secondarily transfers the superimposed toner images onto the recording medium P. As shown in  FIG. 7 , the transfer device  217  includes the transfer belt  213 , primary transfer rollers  226 , and a transfer cylinder  251  instead of the opposing cylinder  250 . The transfer cylinder  251  is an example of the rotary body, and the transfer belt  213  is an example of a transfer unit. 
     Each primary transfer roller  226  is a roller that transfers the toner image of the photoconductor  224  of the corresponding color to the transfer belt  213  at a primary transfer position T 1  between the photoconductor  224  and the primary transfer roller  226 . In the present exemplary embodiment, a primary transfer electric field is applied between the primary transfer roller  226  and the photoconductor  224 , so that the toner image formed on the photoconductor  224  is transferred to the transfer belt  213  at the primary transfer position T 1 . 
     The toner images are transferred from the photoconductors  224  of the respective colors to the outer peripheral surface of the transfer belt  213 . As shown in  FIG. 7 , the transfer belt  213  has an endless shape. The transfer belt  213  is wound on plural rollers  232  and an opposing roller  234  so as to have an inverted triangle shape in a front view (as viewed in the apparatus depth direction). The transfer belt  213  circulates in a direction of an arrow A as at least one of the plural rollers  232  is rotationally driven. 
     The transfer cylinder  251  is a transfer body that transfers the toner image transferred to the transfer belt  213  to the recording medium P at a secondary transfer position T 2  between the opposing roller  234  and the transfer cylinder  251 . In the present exemplary embodiment, when a secondary transfer electric field is applied between the opposing roller  234  and the transfer cylinder  251 , the toner image transferred to the transfer belt  213  is transferred to the recording medium P at the secondary transfer position T 2 . The transfer belt  213  and the outer peripheral surface of the transfer cylinder  251  are in contact with each other at the secondary transfer position T 2 . The toner image is transferred while the transfer belt  213  and the transfer cylinder  251  transport the recording medium P in a state of nipping the recording medium P at the secondary transfer position T 2 . The transfer cylinder  251  is configured in a similar manner as the opposing cylinder  250  in the first exemplary embodiment. 
     Fixing Device  30   
     In the present exemplary embodiment, the fixing device  30  functions as a device that fixes the toner image transferred to the recording medium P by the transfer cylinder  251  to the recording medium P. Specifically, as shown in  FIG. 1 , the fixing device  30  includes a pressure roller  31  and a heating roller  32 . 
     In the fixing device  30 , the heating roller  32  is disposed above the pressure roller  31 . The heating roller  32  has a heating source  32 A such as a halogen lamp inside the heating roller  32 . 
     The pressure roller  31  has a recess  34  in an outer peripheral surface thereof. One recess  34  is provided in a part of the outer peripheral surface of the pressure roller  31  in a circumferential direction. Further, the recess  34  is elongated along the axial direction of the pressure roller  31  and has a depth along a radial direction of the pressure roller  31 . The grippers  24  and the attachment member  23 , which will be described later, are accommodated in the recess  34 . 
     The pair of sprockets  37  according to the first exemplary embodiment is provided at both axial end portions of the pressure roller  31 . The pair of sprockets  37  is disposed coaxially with the pressure roller  31 , and rotate integrally with the pressure roller  31 . 
     The fixing device  30  fixes the toner image transferred to the recording medium P to the recording medium P by heating and pressing the recording medium P while transporting the recording medium P in a state in which the recording medium P is sandwiched at the fixing position NP between the heating roller  32  and the pressure roller  31 . 
     In the image forming apparatus  200 , as the chain  22  circulates in the circulating direction C in a state in which the grippers  24  hold a leading end portion of the recording medium P, a transport mechanism  12  causes the recording medium P to pass through the secondary transfer position T 2  and a fixing position NP between the pressure roller  31  and the heating roller  32 . Then, the toner images primarily transferred onto the transfer belt  213  in the superimposed manner at the primary transfer positions T 1  of the respective colors are secondarily transferred onto the recording medium P at the secondary transfer position T 2 . The toner image secondarily transferred to the recording medium P is fixed to the recording medium P at the fixing position NP. 
     The cleaning device  15  according to the present exemplary embodiment is configured in a similar manner as the cleaning device  15  in the first exemplary embodiment, and the present exemplary embodiment has a similar effect as that of the first exemplary embodiment. 
     Modification of Separation Mechanism 
     In the first exemplary embodiment, the brake  18  stops the rotation of the opposing cylinder  250  at the position where the recess  254  opposes the brush  72 , to thereby separate the brush  72  from the outer peripheral surface of the opposing cylinder  250 . The present disclosure is not limited thereto. A moving mechanism  50  shown in  FIG. 8  may be used as the separation mechanism. The modification is also applicable to the second exemplary embodiment. In this case, it is assumed that the opposing cylinder  250  described below is replaced with the transfer cylinder  251 . 
     In the present modification, as shown in  FIG. 8 , the body  40  includes attachment portions  44  in addition to the housing  42 . In the present modification, the body  40  of the cleaning device  15  is provided in a body  11  of the image forming apparatus  10  such that the body  40  is movable along the apparatus width direction together with the duct frame  60  and the cleaning unit  70 . Specifically, the body  40  is movable along the apparatus width direction between an approach position shown in  FIG. 8  and a separated position shown in  FIG. 9 . 
     The approach position shown in  FIG. 8  is an approach position with respect to the outer peripheral surface of the opposing cylinder  250 . When the body  40  is located at the approach position and the outer peripheral surface of the opposing cylinder  250  opposes the brush  72 , the brush  72  comes into contact with the outer peripheral surface of the opposing cylinder  250 . When the outer peripheral surface of the opposing cylinder  250  opposes the seal member  78 , the seal member  78  is in contact with the outer peripheral surface of the opposing cylinder  250 . The separated position shown in  FIG. 9  is a separated position with respect to the outer peripheral surface of the opposing cylinder  250 . When the body  40  is located at the separated position, the brush  72  is separated from the outer peripheral surface of the opposing cylinder  250 . 
     As shown in  FIG. 8 , each attachment portion  44  is a part to which a tension spring  52 , which will be described later, of the moving mechanism  50  is attached. Two attachment portions  44  are provided on a side wall  42 B of the housing  42  on a side opposite to the opposing cylinder  250  (on a left side in  FIG. 8 ). 
     The moving mechanism  50  is a mechanism that moves the body  40  between the approach position shown in  FIG. 8  and the separated position shown in  FIG. 9 . Specifically, as shown in  FIG. 8 , the moving mechanism  50  includes the two tension springs  52  and a cam  54 . One end portion of each of the two tension springs  52  is attached to a respective one of the attachment portions  44 . The other end portion of each of the two tension springs  52  is attached to a respective one of attachment portions  13  provided in the body  11  of the image forming apparatus  10 . As a result, the two tension springs  52  pull the cleaning device body  40  toward the separated position (leftward in  FIG. 8 ) relative to the approach position. The cam  54  is provided in the body  11  so as to be swingable about a swing shaft  54 A. 
     When the opposing cylinder  250  transitions from the stop mode to the rotation mode, the cam  54  of the moving mechanism  50  swings and a longer diameter portion of the cam  54  comes into contact with the side wall  42 B of the housing  42 , so that the body  40  is moved to the approaching position shown in  FIG. 8  against an elastic force of the tension springs  52 . 
     When the opposing cylinder  250  transitions from the rotation mode to the stop mode, the cam  54  of the moving mechanism  50  swings and a shorter diameter portion of the cam  54  opposes the side wall  42 B of the housing  42 , so that the body  40  is moved to the separated position shown in  FIG. 9  by the elastic force of the tension springs  52 . As a result, the moving mechanism  50  separates the brush  72  from the outer peripheral surface of the opposing cylinder  250  in a state where the rotation of the opposing cylinder  250  is stopped. 
     In the present modification, since the entire body  40  including the brush  72  and the flicker  74  moves, a positional relationship between the brush  72  and the flicker  74  does not change before and after the body  40  moves to the separated position illustrated in  FIG. 9 . That is, the moving mechanism  50  separates the brush  72  from the outer peripheral surface of the opposing cylinder  250  without changing the positional relationship between the brush  72  and the flicker  74 . 
     In the present modification, the brush  72  can be separated from the outer peripheral surface of the opposing cylinder  250  regardless of the position of the recess  254 , unlike the case where the brake  18  stops the rotation of the opposing cylinder  250  at the position where the recess  254  faces the brush  72  to thereby separate the brush  72  from the outer peripheral surface of the opposing cylinder  250 . 
     Further, in the present modification, the moving mechanism  50  separates the brush  72  from the outer peripheral surface of the opposing cylinder  250  when the removal of the foreign matter is not executed in a state in which the opposing body  250  rotates, that is, in the rotation mode. 
     The case where the removal of the foreign matter is not executed in the rotation mode refers to a case where the foreign matter is less likely to adhere to the opposing cylinder  250  during execution of the image forming process. Specifically, this corresponds to a case where an image area of an image to be formed on the recording medium P is narrower than a predetermined area. 
     Further, in the second exemplary embodiment, the case where the removal of the foreign matter is not executed in the rotation mode may be a case where a size of the recording medium P is equal to or larger than a predetermined size. 
     The rotation device  16  may include both the brake  18  and the moving mechanism  50 . In this configuration, the brake  18  and the moving mechanism  50  are selectively used. For example, when the opposing cylinder  250  transitions from the rotation mode to the stop mode, the brush  72  may be separated from the outer peripheral surface of the opposing cylinder  250  using the brake  18 , and when removal of foreign matter is not executed in the rotation mode, the brush  72  may be separated from the outer peripheral surface of the opposing cylinder  250  using the moving mechanism  50 . 
     Other Modifications 
     In the first and second exemplary embodiment, the brush  72  rotates in a forward direction relative to the rotational direction of the opposing cylinder  250 . The present disclosure is not limited thereto. For example, the brush  72  may rotate in the opposite direction relative to the rotational direction of the opposing cylinder  250 . Also, the brush  72  may not rotate. In this case, for example, the flicker  74  is unnecessary. 
     In the first and second exemplary embodiments, the circumferential speed ratio of the brush  72  to the opposing cylinder  250  is more than 1. The present disclosure is not limited thereto. The circumferential speed ratio of the brush  72  to the opposing cylinder  250  may be 1 or less. 
     In the first and second exemplary embodiments, the flicker  74  is provided. Alternatively, the flicker  74  may not be provided. 
     In the first and second exemplary embodiments, as shown in  FIG. 5 , KA&gt;KB, where KA is the penetration depth of the brush  72  into the flicker  74 , and KB is the penetration depth of the brush  72  into the opposing cylinder  250 . The present disclosure is not limited thereto. For example, a relationship of KA≤KB may be met. 
     In the first and second exemplary embodiments, the cleaning device  15  includes the ducts  91  and  92 . The present disclosure is not limited thereto. For example, the cleaning device  15  may include only one of the duct  91  and the duct  92 . 
     In the secondary exemplary embodiment, the transfer belt  213  as the intermediate transfer body is used as an example of the transfer unit. The present disclosure is not limited thereto. As an example of the transfer portion, a photoconductor may be used. Alternatively, a direct transfer type transfer portion may be used. 
     The present disclosure is not limited to the above exemplary embodiment. Various modifications, changes, and improvements may be made without departing from the scope of the present disclosure. For example, the modifications described above may be combined with each other as appropriate. 
     The foregoing description of the exemplary embodiments of the present disclosure has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in the art. The embodiments were chosen and described in order to best explain the principles of the disclosure and its practical applications, thereby enabling others skilled in the art to understand the disclosure for various embodiments and with the various modifications as are suited to the particular use contemplated. It is intended that the scope of the disclosure be defined by the following claims and their equivalents.