JP2012103339A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of maintaining image quality by securely cleaning a transfer member.SOLUTION: An image forming device comprises: moving means (retracting mechanism 130) for moving to a state in which a removal member (cleaning blade 106) is contacted with a transfer member (transfer belt 100) during removal of a developer or a state in which the removal member is separated from the transfer member during non-removal of a developer; a rotary shaft (camshaft 132) which is connected to the moving means to transmit driving force and is rotatably supported by a pair of bearings disposed at both end sides; and first braking means for braking the rotation of the rotary shaft. The first braking means has a plurality of braking members (braking members 501a and 502b) between a pair of bearings (frame 300).

Description

  The present invention relates to an image forming apparatus.

  In image forming apparatuses such as copiers and printers that form images by electrophotography, the toner image formed on the photoconductor is transferred (primary transfer) onto the intermediate transfer body and then retransferred to a recording medium such as printing paper. A configuration in which an image is formed on a recording medium by (secondary transfer) has been conventionally known.

  As a method of forming a full-color image in a configuration provided with an intermediate transfer member, a toner image of each color component such as Y (yellow), M (magenta), C (cyan), K (black) corresponding to the same full-color image. There is a so-called four-cycle method in which the toner images of the respective color components are sequentially primary-transferred onto the intermediate transfer body so that the toner images of the respective color components overlap each other on the transfer belt.

  By the way, a four-cycle image forming apparatus includes a cleaning device that removes residual toner on the transfer belt, and a blade-like cleaning member provided in the cleaning device is configured to be separated from the transfer belt during image formation. ing.

  The cam shaft that separates the cleaning member is provided with a brake member (braking member) that brakes the rotation of the cam shaft.

  Various techniques for cleaning the transfer belt as described above have been proposed, for example, in Japanese Patent Laid-Open No. 8-114995.

Japanese Patent Laid-Open No. 8-114995

  An object of the present invention is to provide an image forming apparatus that can reliably clean a transfer member and maintain image quality.

  In order to solve the above-described problems, an image forming apparatus according to a first aspect of the present invention includes a transfer member that is configured to be freely circulated around a rotating body and to which an image using a developer is transferred. A removing member for removing the developer remaining on the surface of the member, and a state in which the removing member is in contact with the transfer member when the developer is removed, and a state in which the removing member is separated from the transfer member when not removed. A plurality of moving means, a rotating shaft connected to the moving means for transmitting a driving force and rotatably supported by a pair of bearing portions provided on both end sides; And a first braking unit that has a braking member and brakes the rotation of the rotation shaft.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect of the present invention, each of the braking members is composed of an annular member that is fitted to the rotary shaft through a predetermined gap, and each of the annular members. A pressing member is provided for each, and presses the inner peripheral surface of each annular member against the surface of the rotating shaft.

  According to a third aspect of the present invention, in the image forming apparatus according to the second aspect, the pressing member is an elastic member that pulls each annular member so as to press the inner peripheral surface of each annular member against the surface of the rotating shaft. It is composed of a body.

  An image forming apparatus according to a fourth aspect of the present invention provides the image forming apparatus according to any one of the first to third aspects, wherein at least one of the end portions of the rotating shaft exposed to the outside of the pair of bearing portions is provided. A second braking means for braking the rotation of the rotating shaft is provided.

  According to a fifth aspect of the present invention, in the image forming apparatus according to the third or fourth aspect of the present invention, the second braking means is fitted to the rotary shaft through a predetermined gap. An annular member and an elastic body that pulls each annular member so as to press the inner peripheral surface of the annular member against the surface of the rotating shaft, and the elastic force of the elastic body included in the second braking means is the first force The braking means is configured to balance the total elastic force of each elastic body.

  According to the present invention, the following effects can be obtained.

  That is, according to the first aspect of the present invention, the braking force of the rotating shaft is improved and the transfer member is reliably cleaned without increasing the size of the apparatus as compared with the case where the present structure is not provided. Thus, an image forming apparatus that maintains image quality can be provided.

  According to the second aspect of the present invention, it is possible to provide an image forming apparatus that reliably cleans the transfer member with a simple configuration and maintains the image quality as compared with the case where the present configuration is not provided. .

  According to the invention described in claim 3, it is possible to provide an image forming apparatus that reliably cleans a transfer member with a simple and inexpensive configuration and maintains image quality as compared with the case where the present configuration is not provided. Can do.

  According to the fourth aspect of the present invention, it is possible to provide an image forming apparatus that suppresses the deflection of the rotating shaft and maintains the image quality as compared with the case where the present configuration is not provided.

  According to the fifth aspect of the present invention, it is possible to provide an image forming apparatus that maintains the image quality by more effectively suppressing the deflection of the rotating shaft as compared with the case where the present configuration is not provided.

1 is a configuration diagram illustrating a schematic configuration of an image forming apparatus according to an embodiment. 1 is a configuration diagram illustrating a schematic configuration of a main part of an image forming apparatus according to an embodiment. 1 is a perspective view illustrating a schematic configuration of a main part of an image forming apparatus according to an embodiment. FIG. 3 is a perspective view showing a configuration including a first brake and a second brake in the image forming apparatus according to the embodiment. FIG. 3 is a perspective view showing a configuration including a first brake and a second brake in the image forming apparatus according to the embodiment. 1 is a perspective view illustrating a configuration example of a driving device in an image forming apparatus according to an embodiment. It is a perspective view which shows the structure containing the brake in comparative symmetry.

  Hereinafter, an embodiment as an example of the present invention will be described in detail with reference to the drawings. Here, in the accompanying drawings, the same reference numerals are given to the same members, and duplicate descriptions are omitted. In addition, since description here is the best form by which this invention is implemented, this invention is not limited to the said form.

  Before describing an image forming apparatus according to an embodiment of the present invention, an example to be compared will be described with reference to FIG.

  FIG. 7 shows a state in which the transfer belt is removed in the secondary transfer device of the four-cycle image forming apparatus as a comparison target.

  Formed on the frame 300 are a driving roll 61 that is driven to rotate, a tension applying roll 63 for applying tension to the transfer belt, a transport roll 65 that rotates following contact with the inner peripheral surface of the transfer belt, and a surface of the photoreceptor. A primary transfer roll 67 for primarily transferring the toner image to the outer peripheral surface of the transfer belt, a cam shaft 132 provided with an eccentric cam 134 for bringing a cleaning member (not shown) into contact with and separating from the transfer belt, and the like are provided. .

  The cam shaft 132 is provided with an annular brake member (braking member) 200 that brakes the rotation of the cam shaft 132 at a portion exposed to the outside of the frame 300.

  The brake member 200 is pulled by a spring 201, the inner peripheral surface of the brake member 200 is pressed against the surface of the cam shaft 132, and the rotation of the cam shaft 132 is braked by the generated frictional force. .

  However, since there is only one brake member 200 as a comparison target, there is a possibility that an image defect may occur when the braking force is insufficient.

  That is, the eccentric cam 134 that separates the cleaning member uses a clutch or the like to stop the driving of the eccentric cam 134, but the inertia of the eccentric cam 134 and the cam shaft 132 when the power from the clutch is cut off. Due to the force or the like, the eccentric cam 134 is rotated more than a preset angle, the residual toner is not completely removed, and the quality of the formed image may be deteriorated.

  In order to increase the braking force, it is conceivable to replace the spring 201 with a stronger elastic force. In this case, the cam shaft 132 may bend due to the elastic force of the spring 201.

  Furthermore, when the elastic force of the spring 201 is strong, it is difficult to extend the spring 201 against the elastic force when the apparatus is assembled, and there is a problem that the assembling property is inferior.

  Accordingly, the present inventor has devised an image forming apparatus according to the present invention as a result of intensive studies to solve the above problems.

  An image forming apparatus PR1 according to an embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 1, the overall configuration of the image forming apparatus PR1 according to the present embodiment includes a paper storage unit 12 that stores recording paper P from the lower side to the upper side in the vertical direction, and the paper storage unit 12. The image forming unit 14 for forming an image on the recording paper P supplied from the paper storage unit 12, the document reading unit 16 for reading the document G provided on the upper side of the image forming unit 14, and image formation And a control unit 20 that is provided in the unit 14 and controls the operation of each unit of the image forming apparatus PR1.

  The paper storage unit 12 is provided with a first storage unit 22, a second storage unit 24, and a third storage unit 26 that store recording papers P of different sizes.

  Each of the first storage unit 22, the second storage unit 24, and the third storage unit 26 is provided with a delivery roll 32 that sends the stored recording paper P to the conveyance path 28 in the image forming apparatus PR1.

  A pair of transport rolls 34 and 36 that transport the recording paper P one by one are provided in the transport path 28 on the downstream side of each delivery roll 32.

  Further, a pair of transports are performed so that the recording paper P sent from a reverse transport path 29 (described later) joins the transport path 28 and is transported downstream of the transport roll 36 of the third storage unit 26. A roll 50 is provided.

  An alignment roll 38 that temporarily stops the recording paper P and feeds it to a secondary transfer position described later at a predetermined timing is provided downstream of the transport roll 50.

  The upstream conveyance path 28 including the conveyance roll 50 is formed in a straight line in the vertical direction. The downstream conveyance path 28 including the alignment roll 38 is formed in a substantially straight line from the left side of the image forming unit 14 to the right side, that is, the paper discharge unit 15 provided on the right side surface of the apparatus main body 10A. Furthermore, a reverse conveyance path 29 is provided below the conveyance path 28 on the downstream side including the alignment roll 38 and the recording paper P is reversed and conveyed.

  The reversal conveyance path 29 has a first guide member 31 that guides the recording paper P from the conveyance path 28 to the reversal conveyance path 29, and a straight line in the vertical direction from the lower right side of the image forming unit 14 to the lower right side of the paper storage unit 12. A reversing unit 30 provided on the reversing unit 30, a second guide member 35 for guiding the recording paper P conveyed to the reversing unit 30 from the reversing unit 30 to a conveying unit 37 described later, and a recording sheet guided by the second guiding member 35. And a transport unit 37 for transporting P.

  The downstream side of the transport unit 37 is joined to a transport path 28 between the transport roll 36 and the transport roll 50 of the third storage unit 26. The reversing unit 30 is provided with a pair of transport rolls 42 at a predetermined interval, and the transport unit 37 is provided with a pair of transport rolls 44 at a predetermined interval. It is provided at multiple locations.

  The first guide member 31 has a substantially triangular prism shape, and the leading end portion is moved to either the transport path 28 or the reverse transport path 29 by a driving unit (not shown), so that the recording paper P is transported to the transport path 28 or Guide to the reverse conveyance path 29 is provided.

  Similarly, the second guide member 35 has a substantially triangular prism shape, and the recording paper P is moved to the reversing section by moving the leading end to either the reversing section 30 or the transport section 37 by a driving means (not shown). 30 or the conveyance part 37 is guided.

  Further, a foldable manual sheet feeding unit 46 is provided on the left side surface of the apparatus main body 10A. The recording paper P supplied from the manual paper feed unit 46 is transported by the transport roll 48 and is joined to the transport path 28 downstream of the transport roll 50 and upstream of the alignment roll 38. It has become.

  The document reading unit 16 includes a document transport device 52 that automatically transports the document G one by one, a platen glass 54 that is disposed below the document transport device 52 and on which one document G is placed, and the document transport device 52. And a document reading device 56 that reads the document G conveyed on the platen glass 54 or the document G placed on the platen glass 54.

  The document conveyance device 52 has an automatic conveyance path 55 in which a plurality of pairs of conveyance rolls 58 are arranged. A part of the automatic conveyance path 55 is arranged so that the recording paper P passes over the platen glass 54. Yes. Further, the document reading device 56 reads the document G conveyed by the document conveying device 52 while being stationary at the left end portion of the platen glass 54, or reads the document G placed on the platen glass 54 while moving in the right direction. It is supposed to read.

  The image forming unit 14 includes a cylindrical photosensitive member 62 disposed in the approximate center of the apparatus main body 10A with the direction from the front side to the back side of the apparatus main body 10A being the axial direction.

  The photosensitive member 62 is driven to rotate in the direction of arrow R (clockwise in the figure) by a driving unit (not shown) and holds an electrostatic latent image formed by light irradiation. A corotron charging member 64 that charges the surface of the photoconductor 62 is provided above the photoconductor 62 and at a position facing the surface (outer peripheral surface) of the photoconductor 62.

  An exposure device 66 is provided at a position downstream of the charging member 64 in the rotation direction of the photoconductor 62 and facing the surface of the photoconductor 62. The exposure device 66 is composed of LEDs, and irradiates (exposes) light onto the surface of the photoreceptor 62 charged by the charging member 64 based on an image signal corresponding to each toner color to form an electrostatic latent image. It is supposed to be.

  The exposure device 66 is not limited to the LED system, and may be one that scans laser light with a polygon mirror, for example. Further, the electrostatic latent image formed on the surface of the photoconductor 62 is developed with toner of each predetermined color on the downstream side in the rotation direction of the photoconductor 62 from the portion irradiated with light by the exposure device 66. A rotation switching type developing device 70 is provided.

  The developing device 70 develops corresponding to each toner color of yellow (Y), magenta (M), cyan (C), black (K), first special color (E), and second special color (F). (Not shown). The developing devices are arranged side by side in the circumferential direction, and are switched by being rotated by a central angle of 60 ° by a motor (not shown) that is a rotational drive source so as to face the surface of the photoreceptor 62. ing.

  The first special color (E) and the second special color (F) are, for example, special colors (including transparency) other than yellow (Y), magenta (M), cyan (C), and black (K). When the first special color (E) and the second special color (F) are used, the image is formed with six colors of Y, M, C, K, E, and F. It has become.

  Further, an image may be formed with four colors of Y, M, C, and K and the first special color (E) or the second special color (F), or the first special color (E). The image may be formed with four colors excluding the second special color (F).

  An intermediate transfer unit as an example of a transfer device in which a toner image formed on the surface of the photoconductor 62 is primary-transferred downstream of the developing device 70 in the rotation direction of the photoconductor 62 and below the photoconductor 62. 60 is provided.

  The intermediate transfer unit 60 has an endless transfer belt 100 (intermediate transfer belt: an example of a transfer member) as an example of an image carrier that circulates and moves in the direction of arrow C (counterclockwise in the figure).

  The transfer belt 100 is driven by being in contact with a drive roll 61 that is rotationally driven by the control unit 20, a tension applying roll 63 for applying tension to the transfer belt 100, and the back surface (inner peripheral surface) of the transfer belt 100. It is wound around a plurality of rotating transport rolls 65 and an auxiliary roll 69 that rotates in contact with the back surface of the transfer belt 100 at a secondary transfer position described later.

  Further, on the opposite side of the photoconductor 62 with the transfer belt 100 interposed therebetween, a primary transfer roll 67 for primary transfer of the toner image formed on the surface of the photoconductor 62 to the surface (outer peripheral surface) of the transfer belt 100 is provided. It has been.

  The primary transfer roll 67 is in contact with the back surface of the transfer belt 100 at a position away from the position where the photoconductor 62 and the transfer belt 100 are in contact with each other on the downstream side in the moving direction of the transfer belt 100. When the primary transfer roll 67 is energized from a power source (not shown), the toner image on the photoconductor 62 is primarily transferred onto the surface of the transfer belt 100 by a potential difference from the grounded photoconductor 62. Yes.

  Further, a cleaning device 74 that removes residual toner and the like remaining on the surface of the photoconductor 62 without being primarily transferred to the surface of the transfer belt 100 on the downstream side in the rotation direction of the photoconductor 62 with respect to the primary transfer roll 67. Is provided.

  Further, on the upstream side in the rotation direction of the photoconductor 62 with respect to the cleaning device 74 (downstream side with respect to the primary transfer roll 67), a static elimination device 76 that performs static elimination by irradiating the surface of the photoconductor 62 with light. .

  Further, at the end of the transfer belt 100, a reference mark composed of a reflective seal or the like serving as a reference for image alignment is provided, and a photo sensor 83 is provided so as to face the passing position.

  Further, as shown in FIG. 1, a fixing device 80 for fixing the toner image on the recording paper P on which the toner image is transferred by the secondary transfer roll 72 is provided downstream of the secondary transfer position. Yes. The fixing device 80 includes a heat source that generates heat when energized, a heating roll 82 disposed on the toner image surface side (upper side) of the recording paper P, and a lower side of the heating roll 82. And a pressurizing roll 84 that pressurizes the outer peripheral surface 82.

  A transport roll 40 that transports the recording paper P toward the paper discharge unit 15 or the reversing unit 30 is provided on the downstream side of the fixing device 80. Also, yellow (Y), magenta (M), cyan (C), black (K), first special color (E), and second special are located below the document reader 56 and above the developing device 70. Toner cartridges 78Y, 78M, 78C, 78K, 78E, and 78F that store the respective color (F) toners are provided so as to be replaced side by side in the horizontal direction.

  A cleaning device 150 is provided as an example of a cleaning device that removes and collects residual toner remaining on the surface of the transfer belt 100 without being transferred to the recording paper P after the secondary transfer.

  As shown in FIG. 2, the cleaning device 150 is provided on the housing 102 having a rectangular opening 104 disposed to face the transfer belt 100 and on the upper side of the opening 104, and contacts the transfer belt 100. A cleaning blade 106 as an example of a removing member that removes residual toner, and is provided in the opening 104 at a position opposite to the cleaning blade 106, and comes into contact with the transfer belt 100 between the housing 102 and the transfer belt 100. And a seal member 108 that seals the gap.

  As will be described later, the cleaning blade 106 and the seal member 108 are in contact with and separated from the transfer belt 100.

  Further, the cleaning device 150 includes a conveying member 128 that conveys residual toner stored in the housing 102 to one end in the longitudinal direction, and a suction unit (illustrated) that sucks residual toner and the like into the housing 102. (Not shown), a filter 112 provided in the housing 102 for capturing dust including residual toner, a position where the cleaning blade 106 and the seal member 108 are in contact with the surface of the transfer belt 100 and the surface of the transfer belt 100. And a part of a retract mechanism 130 (see FIG. 3: an example of moving means) that moves between the separated positions.

  As shown in FIG. 3, the retract mechanism 130 includes a first separation mechanism 130A provided in the cleaning device 150 on the front side of the apparatus main body 10A and a second separation mechanism 130A provided on the intermediate transfer unit 60 on the back side of the apparatus main body 10A. And a separation mechanism.

  Note that illustration and description of the second separation mechanism are omitted.

  Further, in the intermediate transfer unit 60, a side plate 124 is provided on the front side of the cleaning device 150, and a side plate 126 is provided on the opposite side (back side) of the cleaning device 150.

  In addition, one end portion of each coil spring 152 is attached to the end portion on the downstream side of the first movable member 110 and on the opposite side to the drawing side and the drawing side, and the other end portion of each coil spring 152 is Attached to the bottoms of the side plates 114 and 116, respectively.

  As a result, a force for rotating in the + J direction acts on the first movable member 110.

  The first separation mechanism 130A includes a first eccentric cam 134 provided at one end of a cam shaft 132 (an example of a rotating shaft) that protrudes outward (front side) from the side plate 124 of the intermediate transfer unit 60, and a cleaning device. 150 is provided on the outer surface side of the side plate 114 so as to be rotatable, and is moved (rotated) by being pressed by the rotating first eccentric cam 134, so that the first movable member 110 and further the second movable member 120 are intermediately disposed. A first link member 142 as an example of a first pressing member that moves in a direction away from the transfer belt 68 is included.

  A cam shaft 132 as an example of a rotation shaft is rotatably supported by a side plate 124 and a side plate 126 as a part of a frame 300 (an example of a bearing portion) of the intermediate transfer unit 60.

  As shown in FIGS. 4 and 5, a coupling member 88 is provided at the back end of the cleaning device 150.

  A coupling member 703 protruding from the drive device 700 as shown in FIG. 6 toward the pull-out side meshes with the coupling member 88 so that the rotational driving force is transmitted from the drive device 700 to the cam shaft 132. It has become.

  As shown in FIG. 6, the driving device 700 is connected to a motor 701 as a driving source, a motor 701 via a gear train 704a, and a clutch 702 that connects and disconnects a driving force, and a clutch 702 and a gear. And a coupling member 703 connected via a row 704b.

  Further, as shown in FIG. 3, in addition to a coil spring 138 (an example of an elastic body) having one end attached to the side plate 124, a predetermined portion of the first eccentric cam 134 that is eccentric about the cam shaft 132 is used. The end is attached.

  The coil spring 138 applies a braking force to the camshaft 132 by pulling a brake member 502 (an example of a braking member) of a second brake B2 (an example of a second braking unit) described later.

  As shown in FIG. 3, the first link member 142 has a configuration in which two plate members having the same shape, which is substantially “V” in a front view, are integrated with a space therebetween.

  An arc-shaped notch 142D fixed to the support shaft 140 is formed at the lower end of the main body 142A. The support shaft 140 can be rotated by a bearing (not shown) provided on the side plate 114. It is supported. Further, rolls 146 and 148 are supported on the upper end of the first arm 142B and the upper end of the second arm 142C, respectively, so as to be rotatable in the same axial direction as the support shaft 140.

  Here, the first link member 142 moves (rotates) around the support shaft 140 (with the support shaft 140 as a fulcrum) in the + J direction (clockwise in FIG. 6) or in the −J direction (counterclockwise in FIG. 6). The first arm 142B and the second arm 142C move in the + J direction or the −J direction.

  The first link member 142 has one end of a coil spring 155 attached to the edge of the main body 142A on the second arm 142C side, and the other end of the coil spring 155 is attached to the bottom of the side plate 114. Yes. As a result, a force that rotates in the + J direction acts on the first link member 142, and the roll 146 does not contact the first eccentric cam 134 in the non-retracting state.

  Next, referring to FIG. 4 and FIG. 5, the first brake B1 (an example of the first braking means) and the second brake B2 (an example of the second braking means) according to the main part of the present embodiment. ) Will be described.

  4 shows a state in which the transfer belt 100 and the cleaning device 150 configured as described above are provided, and FIG. 5 shows a state in which the transfer belt 100 and the cleaning device 150 are removed.

  As described above, the frame 300 includes a driving roll 61 that is rotationally driven, a tension applying roll 63 that applies tension to the transfer belt, a conveyance roll 65 that rotates in contact with the inner peripheral surface of the transfer belt, and a photosensitive member. A primary transfer roll 67 for primary transfer of a toner image formed on the surface of the body to the outer peripheral surface of the transfer belt, a cam shaft 132 provided with an eccentric cam 134 for bringing a cleaning member (not shown) into contact with and separating from the transfer belt, etc. Is provided.

  The cam shaft 132 is provided with a first brake B1 (an example of a first braking unit) and a second brake B2 (an example of a second braking unit).

  Specifically, the first brake B1 (B1a, B1b) is located between the pair of bearing portions 300a, 300b provided at both ends of the frame 300 and more than the intermediate position 132a in the axial direction of the camshaft 132. A plurality of braking members 501a and 501b are provided at symmetrical positions near both ends (three in the example shown in FIGS. 4 and 5).

  More specifically, each of the braking members 501a and 501b includes an annular member formed of a plastic such as polyethylene that is fitted to the cam shaft 132 through a predetermined gap (for example, several tens of μm). Pushing members 550a and 550b that are provided for each of the annular members 501a and 501b and press the inner peripheral surface of each of the annular members 501a and 501b against the surface of the cam shaft 132 are provided.

  In the present embodiment, the pressing members 550a and 550b are not particularly limited, and are configured by, for example, a coil spring having an elastic force of 16N.

  In this embodiment, three coil springs 550a and 550b are provided at the left and right symmetrical positions of the cam shaft 132. However, the present invention is not limited to this, and the same number of coil springs 550a and 550b at the left and right symmetrical positions (for example, 2 It is sufficient that the number is four by four.

  In addition, the method of attaching the coil springs 550a and 550b to the respective annular members 501a and 501b is not particularly limited. A portion 800 is provided (see FIG. 3 showing an annular member 502 having a similar configuration).

  Further, the method of attaching the other ends of the coil springs 550a and 550b is not particularly limited, but in this embodiment, as shown in FIGS. 4 and 5, the attachment member 801 that is screwed to the bottom surface 300c of the frame 300 is used. The other ends of the coil springs 550a and 550b are hooked and fixed.

  Further, as described above, one end of the cam shaft 132 exposed to the outside of the pair of bearing portions 300a and 300b has a second brake B2 (second braking means) for braking the rotation of the cam shaft 132. Example) is provided.

  In the present embodiment, the second brake B2 is provided only at one end of the cam shaft 132, but it is also conceivable to provide the second brake B2 at the other end of the cam shaft 132. .

  Further, the second brake B2 includes a braking member 502.

  Similar to the braking members 501a and 501b, the braking member 502 is an annular member formed of a plastic such as polyethylene that is fitted to the cam shaft 132 via a predetermined gap (for example, several tens of μm). As a pressing member that presses the inner peripheral surface of the annular member 502 against the surface of the cam shaft 132, for example, a coil spring 138 having an elastic force of 27N is connected.

  Here, the relationship between the elastic force of the coil springs 550a and 550b and the elastic force of the coil spring 138 is such that, for example, the elastic force of the coil spring 138 is balanced with the total of the coil springs 550a and 550b (that is, a total of six resultant forces). Composed.

  As a result, the braking force applied to the entire cam shaft 132 is improved as compared with comparative symmetry, and as a result, the transfer belt 100 is reliably cleaned and the image quality is maintained.

  In addition, since the elastic force of the coil springs 550a and 550b is selected to be relatively weak, when the first brake B1 is assembled, the coil springs 550a and 550b are relatively easily extended, and the assemblability is improved.

  Further, since the elastic force of the coil spring 138 is balanced with the total elastic force of the coil springs 550a and 550b, the external force applied to the entire cam shaft 132 is canceled, and the bending of the cam shaft 132 is suppressed.

  Further, since the first brake B1 (B1a, B1b) fits inside the frame 300, the image forming apparatus PR1 does not increase in size.

  Although the invention made by the present inventor has been specifically described based on the embodiments, the embodiments disclosed herein are illustrative in all respects and are not limited to the disclosed technology. Should not be considered. That is, the technical scope of the present invention should not be construed restrictively based on the description in the above embodiment, but should be construed according to the description of the scope of claims. All modifications that fall within the scope of the claims and the equivalent technology are included.

  The image forming apparatus according to the present invention can be applied to a printer, a multifunction machine, and the like.

PR1 Image forming apparatus B1 (B1a, B1b) First brake B2 Second brake 100 Transfer belt 150 Cleaning device 12 Paper storage unit 14 Image forming unit 15 Paper discharge unit 16 Document reading unit 20 Control unit 22 Storage unit 24 Storage unit 26 container 28 transport path 29 reverse transport path 30 reverse section 31 guide member 32 delivery roll 34 transport roll 35 guide member 36 transport roll 37 transport section 38 roll 40 transport roll 42 transport roll 44 transport roll 46 manual paper feed section 48 transport Roll 50 Conveying roll 52 Document conveying device 54 Platen glass 55 Automatic conveying path 56 Document reading device 58 Conveying roll 60 Intermediate transfer unit 61 Drive roll 62 Photosensitive member 63 Tension applying roll 64 Charging member 65 Conveying roll 66 Exposure device 67 Primary transfer roll 69 Auxiliary roll 70 Developing device 72 Secondary Copy roll 74 Cleaning device 78 Toner cartridge 80 Fixing device 82 Heating roll 83 Photo sensor 84 Pressure roll 102 Housing 104 Opening portion 106 Cleaning blade 108 Sealing member 110 Movable member 112 Filter 114 Side plate 120 Movable member 124 Side plate 126 Side plate 128 Conveying member 130 Retraction mechanism 132 Cam shaft 132a Intermediate position 134 Eccentric cam 138 Coil spring 140 Support shaft 142 Link member 142A Body portion 142B Arm 142C Arm 142D Notch portion 146 Roll 152 Coil spring 200 Brake member 201 Spring 300 Frame 300a, 300b Bearing portion 300c Bottom surface 501a, 502b Braking member 502 Braking member 550a Coil spring 700 Drive device 701 Motor 702 Clutch 703 Coupling Grayed member 704a gear train 704b gear train 800 hook portion 801 mounting member

Claims (5)

A transfer member that is wound around a rotating body and configured to freely circulate and to which an image using a developer is transferred;
A removal member for removing the developer remaining on the surface of the transfer member;
Moving means for moving the removing member into contact with the transfer member when removing the developer and moving the removing member away from the transfer member when not removing;
A rotating shaft coupled to the moving means to transmit a driving force and rotatably supported by a pair of bearing portions provided at both ends;
A first braking means that has a plurality of braking members between the pair of bearing portions and brakes rotation of the rotating shaft;
An image forming apparatus comprising: Each of the braking members is composed of an annular member that is fitted to the rotating shaft via a predetermined gap,
The image forming apparatus according to claim 1, further comprising a pressing member that is provided for each annular member and presses an inner peripheral surface of each annular member against a surface of the rotation shaft. The pressing member is
The image forming apparatus according to claim 2, wherein the image forming apparatus includes an elastic body that pulls each annular member so as to press an inner peripheral surface of each annular member against a surface of the rotation shaft.   The second braking means for braking the rotation of the rotary shaft is provided on at least one of the end portions of the rotary shaft exposed to the outside of the pair of bearing portions. The image forming apparatus according to any one of the above. The second braking means includes
An annular member that is fitted to the rotary shaft through a predetermined gap;
An elastic body that pulls each annular member so as to press the inner peripheral surface of the annular member against the surface of the rotating shaft;
With
The elastic force of the elastic body provided in the second braking means is configured to balance the total elastic force of the elastic bodies provided in the first braking means. The image forming apparatus according to any one of the above.

Images