JP6477119B2 - Cleaning structure, charging device, assembly, and image forming apparatus - Google Patents

Description

  The present invention relates to a cleaning structure, a charging device, an assembly, and an image forming apparatus.

  In Patent Literature 1, a charging roll as a body to be cleaned is cleaned by a cleaning member in which a cleaning material is spirally disposed on the outer peripheral surface of the shaft portion from one end side to the other end side in the axial direction of the shaft portion. A configuration is disclosed.

JP 2011-145415 A

  In the configuration in which the object to be cleaned is cleaned with a cleaning material spirally disposed from one end side to the other end side in the axial direction of the shaft portion on the outer peripheral surface of the shaft portion, further improvement in cleaning performance of the cleaning material is required. ing.

  An object of this invention is to improve the cleaning performance of a cleaning material compared with the case where the helical angle of a cleaning material and the helical angle of the unevenness | corrugation of the surface layer in a to-be-cleaned body are the same.

  The invention of claim 1 includes a rotating body to be cleaned, a shaft portion disposed along the rotational axis direction of the body to be cleaned, and an outer peripheral surface of the shaft portion from one end side in the axial direction of the shaft portion. It is arranged from the one end side to the other end side in the direction of the rotation axis on the outer peripheral surface of the cleaning material, which is arranged in a spiral shape over the end side, and contacts the outer peripheral surface of the target object, And a surface layer having irregularities arranged in a spiral shape having a spiral angle different from the spiral angle of the cleaning material and contacting the cleaning material.

  According to a second aspect of the present invention, the unevenness of the surface layer is arranged in a spiral shape reverse to the spiral of the cleaning material.

  According to a third aspect of the present invention, there is provided a rotating body to be cleaned, a shaft portion disposed along a rotational axis direction of the body to be cleaned, and an outer peripheral surface of the shaft portion from one end side in the axial direction of the shaft portion. It is arranged from the one end side to the other end side in the direction of the rotation axis on the outer peripheral surface of the cleaning material, which is arranged in a spiral shape over the end side, and contacts the outer peripheral surface of the target object, A surface layer having a high and low friction coefficient portion arranged in a spiral shape having a spiral angle different from the spiral angle of the cleaning material, and contacting the cleaning material.

  According to a fourth aspect of the present invention, the object to be cleaned is a charged object that charges the object to be charged, and the difference between the minimum value and the maximum value of the friction coefficient in the surface layer is 0.03 or more and 0.2 or less. is there.

  A fifth aspect of the present invention is a charging device having the cleaning structure according to any one of the first to fourth aspects, wherein the body to be cleaned includes a charging body that charges the body to be charged.

  A sixth aspect of the present invention is the cleaning structure according to any one of the first to fourth aspects, further comprising: an image holding body capable of holding an image; and a charging body that charges the image holding body as the object to be cleaned. Is an assembly assembled to the apparatus main body so as to be detachable integrally.

  A seventh aspect of the present invention is the cleaning structure according to any one of the first to fourth aspects, further comprising: an image holding body capable of holding an image; and a charging body that charges the image holding body as the object to be cleaned. .

  According to the structure of Claim 1 of this invention, the cleaning performance of a cleaning material can be improved compared with the case where the helical angle of a cleaning material and the helical angle of the unevenness | corrugation of a surface layer are the same.

  According to the configuration of the second aspect of the present invention, the surface layer unevenness is different from the spiral angle of the cleaning material compared to the case where the surface layer unevenness is arranged in a spiral shape in the same winding direction as the cleaning material spiral. The degree of freedom of the set angle when setting the angle is increased.

  According to the structure of Claim 3 of this invention, the cleaning performance of a cleaning material can be improved compared with the case where the spiral angle of a cleaning material and the spiral angle of the high and low part of the friction coefficient in a surface layer are the same.

  According to the configuration of the fourth aspect of the present invention, the charging member has poor charging compared with the case where the difference between the minimum value and the maximum value of the friction coefficient in the surface layer is less than 0.03 or more than 0.2. Can be suppressed.

  According to the configuration of claim 5 of the present invention, charging of the charged body is performed as compared with the case where the spiral angle of the unevenness of the surface layer, or the high and low portions of the friction coefficient in the surface layer, and the spiral angle of the cleaning material are the same. Defects can be suppressed.

  According to the structure of Claim 6 and Claim 7 of this invention, compared with the case where the spiral angle of the unevenness | corrugation of a surface layer, or the high and low part of the friction coefficient in a surface layer, and the spiral angle of a cleaning material are the same, Image defects due to charging failure of the charging device can be suppressed.

1 is a schematic diagram illustrating a configuration of an image forming apparatus according to a first embodiment. It is the schematic which shows the structure of the charging device which concerns on 1st Embodiment. It is the schematic which shows the coating method used for formation of the surface layer of the charging roll which concerns on 1st Embodiment. It is a figure which shows the cross section along the axial direction of the axial part in the cleaning material which concerns on 1st Embodiment. It is explanatory drawing for demonstrating the behavior in the cleaning operation | movement of the cleaning material which concerns on 1st Embodiment. It is the schematic which shows the structure of the charging device which concerns on 2nd Embodiment. It is explanatory drawing for demonstrating the behavior in the cleaning operation of the cleaning material which concerns on 2nd Embodiment. It is the schematic which shows the structure of the charging device which concerns on a modification. It is a table | surface which shows the evaluation result of an Example and a comparative example.

  Below, an example of an embodiment concerning the present invention is described based on a drawing.

<First Embodiment>
(Configuration of image forming apparatus 10)
The configuration of the image forming apparatus 10 according to the present embodiment will be described. FIG. 1 is a schematic diagram illustrating a configuration of an image forming apparatus 10 according to the present embodiment. In addition, arrow UP shown in a figure shows the vertical direction upper direction.

  As shown in FIG. 1, the image forming apparatus 10 includes an image forming apparatus main body 11 in which each component is housed. Inside the image forming apparatus main body 11, a recording medium accommodating unit 12 that accommodates a recording medium P such as paper, an image forming unit 14 that forms an image on the recording medium P, and the recording medium accommodating unit 12 to the image forming unit. 14, a transport unit 16 that transports the recording medium P to 14, and a control unit 20 that controls the operation of each unit of the image forming apparatus 10. In addition, a recording medium discharge unit 18 for discharging the recording medium P on which an image is formed by the image forming unit 14 is provided on the upper portion of the image forming apparatus main body 11.

  The image forming unit 14 includes image forming units 22Y, 22M, 22C, and 22K (hereinafter referred to as 22Y to 22K) that form toner images of colors of yellow (Y), magenta (M), cyan (C), and black (K). And an intermediate transfer belt 24 to which the toner images formed by the image forming units 22Y to 22K are transferred, and a transfer member for transferring the toner images formed by the image forming units 22Y to 22K to the intermediate transfer belt 24. A first transfer roll 26; a second transfer roll 28 as a transfer member for transferring the toner image transferred to the intermediate transfer belt 24 by the first transfer roll 26 from the intermediate transfer belt 24 to the recording medium P; and a second transfer roll A fixing device 30 for fixing the toner image transferred from the intermediate transfer belt 24 to the recording medium P by the recording medium P to the recording medium P. There.

  The image forming units 22 </ b> Y to 22 </ b> K are arranged side by side at the center in the vertical direction of the image forming apparatus 10 while being inclined with respect to the horizontal direction. Each of the image forming units 22Y to 22K has a photosensitive member 32 (an example of a charged member) that rotates in one direction (clockwise direction in FIG. 1) as an example of an image holding member that holds an image. . Since the image forming units 22Y to 22K are configured in the same manner, the reference numerals of the respective parts of the image forming units 22M, 22C, and 22K are omitted in FIG.

  Around each photoconductor 32, a charging device 34 having a charging roll 70 (an example of a charged body, an example of a member to be cleaned) for charging the photoconductor 32 in order from the upstream side in the rotation direction of the photoconductor 32, and a charging roll An exposure device 36 that exposes the photosensitive member 32 charged by 70 to form an electrostatic latent image on the photosensitive member 32, and a toner image is formed by developing the electrostatic latent image formed on the photosensitive member 32 by the exposure device 36. A developing device 38 for removing the toner remaining on the photosensitive member 32 by contacting the photosensitive member 32 and a removing member 40 for removing the toner remaining on the photosensitive member 32 are provided. The specific configuration of the charging device 34 will be described later.

  The exposure device 36 is configured to form an electrostatic latent image based on the image signal sent from the control unit 20. Examples of the image signal sent from the control unit 20 include an image signal acquired by the control unit 20 from an external device.

  The developing device 38 includes a developer supply body 38A that supplies the developer to the photoconductor 32, and a plurality of transport members 38B that transport the developer applied to the developer supply body 38A while stirring.

  Each of the image forming units 22 </ b> Y to 22 </ b> K is configured to be detachable from the image forming apparatus main body 11, and functions as an assembly (process cartridge) assembled to the image forming apparatus main body 11 so as to be detachable integrally. It should be noted that the assembly of this embodiment only needs to include at least the photoconductor 32 and the charging device 34.

  The image forming units 22 </ b> Y to 22 </ b> K may be configured to be supported by a common support frame and not attached to or detached from the image forming apparatus main body 11 without being unitized.

  As shown in FIG. 1, the intermediate transfer belt 24 is formed in an annular shape and is disposed above the image forming units 22 </ b> Y to 22 </ b> K. On the inner peripheral side of the intermediate transfer belt 24, winding rolls 42 and 44 around which the intermediate transfer belt 24 is wound are provided. The intermediate transfer belt 24 circulates (rotates) in one direction (counterclockwise direction in FIG. 1) while being in contact with the photosensitive member 32 when any of the winding rolls 42 and 44 is rotationally driven. ing. The winding roll 42 is an opposing roll that faces the second transfer roll 28.

  The first transfer roll 26 faces the photoconductor 32 with the intermediate transfer belt 24 interposed therebetween. A space between the first transfer roll 26 and the photoconductor 32 is a first transfer position where the toner image formed on the photoconductor 32 is transferred to the intermediate transfer belt 24. The first transfer roll 26 is in contact with the intermediate transfer belt 24 and is configured to rotate following the intermediate transfer belt 24 that circulates and moves.

  The second transfer roll 28 faces the winding roll 42 with the intermediate transfer belt 24 interposed therebetween. A space between the second transfer roll 28 and the winding roll 42 is a second transfer position where the toner image transferred to the intermediate transfer belt 24 is transferred to the recording medium P.

  The transport unit 16 is disposed along the transport path 48, a feed roll 46 that feeds the recording medium P accommodated in the recording medium container 12, a transport path 48 that transports the recording medium P sent to the transport roll 46, and the transport path 48. A plurality of transport rolls 50 are provided for transporting the recording medium P delivered by the delivery roll 46 to the second transfer position.

  The fixing device 30 is disposed downstream in the transport direction from the second transfer position, and fixes the toner image transferred at the second transfer position to the recording medium P. A discharge roll 52 that discharges the recording medium P on which the toner image is fixed to the recording medium discharge unit 18 is provided downstream of the fixing device 30 in the transport direction.

(Configuration of charging device 34)
A configuration of the charging device 34 according to the present embodiment will be described. FIG. 2 is a schematic diagram illustrating a configuration of the charging device 34 according to the present embodiment.

  As shown in FIG. 2, the charging device 34 cleans the charging roll 70 by removing the above-described charging roll 70 (an example of a charged body, an example of an object to be cleaned) and deposits attached to the charging roll 70. And a cleaning member 60. There is a developer as an adhering substance adhering to the charging roll 70. In the charging device 34, a cleaning structure is configured by the charging roll 70 and the cleaning member 60. Hereinafter, specific configurations of the charging roll 70 and the cleaning member 60 will be described.

(Charging roll 70)
The charging roll 70 is driven to rotate in contact with the outer peripheral surface of the rotating photosensitive member 32 (see FIG. 1), and charges the outer peripheral surface of the photosensitive member 32. Specifically, as shown in FIG. 2, the charging roll 70 includes a conductive support 72 as a shaft portion, and a conductive elastic layer 74 (see FIG. 3) formed on the outer peripheral surface of the conductive support 72. And a surface layer 76 formed from one end side to the other end side in the rotation axis direction (the axial direction of the conductive support 72) on the outer peripheral surface of the conductive elastic layer 74.

  The both ends in the axial direction of the conductive support 72 are supported by support members 92 and 94 via bearing portions 82 and 84, respectively.

  The conductive support 72 functions as an electrode and a support member for the charging roll 70. Examples of the material of the conductive support 72 include metals such as iron (free-cutting steel), copper, brass, stainless steel, aluminum, nickel, and alloys containing these metals. In addition, examples of the material of the conductive support 72 include a member (for example, a resin or ceramic member) whose outer peripheral surface is plated, a member in which a conductive agent is dispersed (for example, a resin or ceramic member), and the like. Further, the conductive support 72 may be a cylindrical member or a columnar member.

  The conductive elastic layer 74 includes an elastic material and a conductive agent, and may further include other additives. Examples of the elastic material include isoprene rubber, chloroprene rubber, epichlorohydrin rubber, butyl rubber, urethane rubber, silicone rubber, fluorine rubber, styrene-butadiene rubber, butadiene rubber, nitrile rubber, ethylene propylene rubber, epichlorohydrin-ethylene. Examples thereof include oxide copolymer rubber, epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer rubber, ethylene-propylene-diene copolymer rubber, acrylonitrile-butadiene copolymer rubber, natural rubber, and rubber obtained by mixing these. These elastic materials may be foamed or non-foamed.

  As the conductive agent, an electronic conductive agent or an ionic conductive agent is used. Examples of the electronic conductive agent include carbon black such as ketjen black and acetylene black; pyrolytic carbon, graphite; various conductive metals or alloys such as aluminum, copper, nickel, stainless steel; tin oxide, indium oxide, titanium oxide And fine powders such as various conductive metal oxides such as tin oxide-antimony oxide solid solution, tin oxide-indium oxide solid solution, and the like. Examples of the ion conductive agent include known salts such as quaternary ammonium salts; alkali metal perchlorates; alkaline earth metal perchlorates; These conductive agents may be used alone or in combination of two or more.

  Other additives include foaming agents, foaming aids, softeners, plasticizers, curing agents, vulcanizing agents, vulcanization accelerators, antioxidants, surfactants, coupling agents, fillers (silica, carbonic acid) Usually, materials that can be added to the elastic layer, such as calcium, etc., can be mentioned.

  The surface layer 76 includes a resin and a conductive agent, and may further include other additives. Examples of the resin include acrylic resin, fluorine-modified acrylic resin, silicone-modified acrylic resin, cellulose resin, polyamide resin, copolymer nylon, polyurethane resin, polycarbonate resin, polyester resin, polyimide resin, epoxy resin, silicone resin, and polyvinyl alcohol resin. , Polyvinyl butyral resin, cellulose resin, polyvinyl acetal resin, ethylene tetrafluoroethylene resin, melamine resin, polyethylene resin, polyvinyl resin, polyarylate resin, polythiophene resin. Polyethylene terephthalate resin (PET), fluororesin (polyvinylidene fluoride resin, tetrafluoroethylene resin, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), etc. ). The resin may be one obtained by curing or crosslinking a curable resin using a curing agent or a catalyst. The resin may be used alone or in combination of two or more. Copolymer nylon is a copolymer containing one or more of 610 nylon, 11 nylon, and 12 nylon as polymerized units. The copolymer nylon may contain other polymer units such as 6 nylon and 66 nylon.

  Among these resins, polyvinylidene fluoride resin, tetrafluoroethylene resin, and polyamide resin are desirable for the purpose of suppressing contamination of the charging member surface, and polyamide resin is more desirable from the viewpoint of wear resistance of the charging member surface.

  As the polyamide resin, alkoxymethylated polyamide (alkoxymethylated nylon) is desirable from the viewpoint of wear resistance on the surface of the charging member, and from the viewpoint of holding the resin particles (resin filler) and suppressing detachment from the surface layer. Polyamide (N-methoxymethylated nylon) is more desirable.

  Examples of the conductive agent include those already described as being included in the conductive elastic layer 74. A conductive agent may be used individually by 1 type, and may use 2 or more types together.

  Further, the surface layer 76 may include resin particles (resin filler) for the purpose of adjusting the surface roughness (surface friction coefficient). As the resin particles used for this purpose, porous resin particles are suitable. Examples of the porous resin particles include porous particles made of polyamide resin, polyimide resin, polyacrylic acid resin, polymethacrylic resin, polystyrene resin, fluororesin, silicone resin, and the like.

  Here, the surface layer 76 has spirally arranged irregularities swirling around the rotation axis of the charging roll 70 from one axial end side to the other axial end side of the charging roll 70 (conductive support 72). Have. Specifically, the unevenness of the surface layer 76 is swung counterclockwise from the end portion on the bearing portion 82 side of the charging roll 70 toward the end portion (A direction) on the bearing portion 84 side as viewed in the direction A. Are arranged in a spiral.

  In the present embodiment, for example, the solid line portion in the figure is the convex portion 70A, and the portion other than the solid line portion is the concave portion 70B. Unevenness of the surface layer 76 is formed by the protrusions 70A and the recesses 70B. The height of the unevenness of the surface layer 76 (the difference in height between the convex portion 70A and the concave portion 70B) is set in a range in which the influence of image quality such as charging unevenness is allowed. Specifically, the height of the unevenness is, for example, 5 μm or more and 10 μm or less.

(Formation of surface layer 76)
The surface layer 76 is formed by dispersing each component of the surface layer 76 in a solvent to prepare a coating solution, applying the coating solution on the conductive elastic layer 74, and then heating.

  Examples of the solvent used in the coating solution include alcohols such as methanol, ethanol, propanol, and butanol; ketones such as acetone and methyl ethyl ketone; tetrahydrofuran; ethers such as diethyl ether and dioxane;

  As a coating method of the coating liquid, for example, a flow coating method is used. As shown in FIG. 3, the coating apparatus 100 used in the flow coating method includes, for example, a rotating unit 120, a discharge unit 130, a plate-like blade 140, and a moving mechanism 150.

  The rotating unit 120 rotationally drives the conductive support 72 in a state where both ends in the axial direction of the conductive support 72 are rotatably supported by a support member (not shown). The discharging unit 130 discharges the coating liquid 114 onto the outer peripheral surface of the conductive elastic layer 74 rotated by the rotating unit 120 while moving along the axial direction of the conductive support 72 by the moving mechanism 150. As a result, the coating liquid 114 is spirally applied to the outer peripheral surface of the conductive elastic layer 74. Specifically, the coating liquid 114 is applied to the outer peripheral surface of the conductive elastic layer 74 so that a part of the coating liquid 114 overlaps in the axial direction of the conductive support 72. This overlapping portion becomes the convex portion 70A of the surface layer 76.

  The contact load of the blade 140 with respect to the conductive elastic layer 74 is set such that the overlapping portion of the coating liquid 114 remains as a convex portion. As a result, the blade 140 is moved along the axial direction of the conductive support 72 by the moving mechanism 150, and the coating liquid 114 applied to the outer peripheral surface of the conductive elastic layer 74 is left uneven. The liquid 114 is smoothed. Thereby, the coating film which has an unevenness | corrugation is formed. The surface layer 76 is formed by heating and drying the coating film.

(Cleaning member 60)
As shown in FIG. 2, the cleaning member 60 includes a shaft portion 64 disposed along the axial direction of the charging roll 70, and an outer peripheral surface of the shaft portion 64 from one end side to the other end side in the axial direction of the shaft portion 64. And a cleaning material 66 arranged in a spiral shape over the edge.

  The shaft portion 64 is formed in a columnar shape and has a length along the axial direction of the charging roll 70. Moreover, the axial part 64 is comprised with the metal material, for example. Both end portions in the axial direction of the shaft portion 64 are supported by support members 91 and 93 via bearing portions 81 and 83, respectively.

  The cleaning material 66 is made of, for example, a porous material such as a foam material (sponge) formed of urethane resin or the like, and is formed in a belt shape and elastically deformable. The cleaning material 66 is helically fixed to the outer peripheral surface of the shaft portion 64 from one end side to the other end side in the axial direction by an adhesive, a double-sided tape, or the like.

  As shown in FIG. 4, the cleaning material 66 has a quadrilateral shape surrounded by four sides (including a curve) in the cross section along the axial direction S of the shaft portion 64, and the axial direction of the shaft portion 64. At both ends in S, there is a protruding portion 66A that protrudes outward in the radial direction R from the central portion 66B. The protrusion 66A is formed along the length direction of the cleaning material 66.

  The protrusion 66A, for example, applies a tension to the cleaning material 66, thereby causing an outer diameter difference between the central portion 66B of the outer peripheral surface (upper surface in FIG. 4) of the cleaning material 66 and both end portions 66A. It is formed by letting. In addition, the cleaning material 66 has a quadrilateral shape surrounded by four sides (including a curve) in the cross section along the direction orthogonal to the length direction (P direction in FIG. 2). It has protrusions 66A that protrude outward in the radial direction R at both ends in the width direction.

  In the cleaning member 60, the protruding portion 66A and the outer peripheral surface (the upper surface in FIG. 4) of the cleaning material 66 are in contact with the charging roll 70, and the shaft portion 64 and the cleaning material 66 are integrally rotated. Thereby, the outer peripheral surface of the cleaning material 66 wipes the outer peripheral surface of the charging roll 70, and the protrusion 66 </ b> A of the cleaning material 66 scrapes off the foreign material so that the foreign material is removed.

  Here, the cleaning material 66 is arranged in a spiral shape wound in a reverse direction to the spiral of the irregularities of the surface layer 76. Specifically, as shown in FIG. 2, the cleaning material 66 is arranged in a spiral shape that turns clockwise from the bearing portion 81 side to the bearing portion 83 side (A direction) as viewed in the direction of the arrow A. Has been.

  Thus, the spiral angle θ1 of the cleaning material 66 and the spiral angle θ2 of the unevenness of the surface layer 76 are different. The spiral angle θ1 is an angle at which the axial direction Q1 of the shaft portion 64 and the length direction P1 of the cleaning material 66 intersect in the side view (the angle on the right side and the upper side in FIG. 2 when viewed from the intersection). Further, the spiral angle θ2 is an angle (intersection point) at which the axial direction Q2 of the conductive support 72 in the side view (rotational axis direction of the charging roll 70) and the formation direction (length direction) P2 of the surface layer 76 intersect. (The right and upper angles in FIG. 2). The spiral angle θ1 is an obtuse angle, and the spiral angle θ2 is an acute angle.

(Operation of this embodiment)
Next, the operation of this embodiment will be described.

  In the present embodiment, foreign substances such as developer remaining on the photoconductor 32 without being transferred to the intermediate transfer belt 24 are removed from the photoconductor 32 by the removing member 40. Part of the foreign matter such as a developer that has passed through the removal member 40 without being removed by the removal member 40 adheres to the surface of the charging roll 70 (see FIG. 1).

  As for the foreign matter adhering to the surface of the charging roll 70, the protrusion 66 </ b> A and the outer peripheral surface (upper surface in FIG. 4) of the cleaning material 66 come into contact with the charging roll 70, and the outer peripheral surface of the cleaning material 66 is the outer peripheral surface of the charging roll 70. The protrusion 66A of the cleaning material 66 is removed by scraping off the foreign matter.

  Specifically, as shown in FIGS. 5A and 5B, the foreign matter adhering to the outer circumferential surface of the charging roll 70 rotating in one direction (counterclockwise in FIG. 5) is driven and rotated by the cleaning member 60 that rotates. The protruding portion 66A of the cleaning material 66 is pushed by the outer peripheral surface of the charging roll 70, and the height direction of the cleaning material 66 (G direction shown in FIG. 5A) and the width direction (H shown in FIG. 5A). The elastic material is elastically deformed (elastically compressed) in the direction, and is pushed and aggregated by the cleaning material 66. Then, as shown in FIG. 5C, the aggregated foreign substances such as external additives are more dense than the restoring force by restoring the charging roll 70 in the cleaning material 66 of the cleaning member 60 that is driven to rotate. It is loosened from the state or repelled from the outer peripheral surface of the charging roll 70.

  Here, in this embodiment, the spiral angle θ1 of the cleaning material 66 and the spiral angle θ2 of the unevenness of the surface layer 76 are different. Thereby, when the charging roll 70 and the cleaning member 60 rotate, the convex portion 70 </ b> A of the surface layer 76 crosses the protruding portion 66 </ b> A formed in the longitudinal direction of the cleaning material 66. That is, the convex portion 70A and the protruding portion 66A intersect. Therefore, as shown in FIG. 5B, the protrusion 66 </ b> A of the cleaning material 66 is caught or pushed by the convex portion 70 </ b> A of the surface layer 76, and the spiral angle θ <b> 1 of the cleaning material 66 and the surface layer 76. The amount of deformation of the protrusion 66A is locally increased as compared with the case where the concave and convex spiral angle θ2 is the same. For this reason, the scraping performance by which the protrusion 66A of the cleaning material 66 scrapes off the foreign matter is improved.

  That is, according to the configuration of the present embodiment, the cleaning performance of the cleaning material 66 is improved as compared with the case where the spiral angle θ1 of the cleaning material 66 and the spiral angle θ2 of the unevenness of the surface layer 76 are the same. Thereby, the charging failure resulting from the cleaning failure of the charging roll 70 and the image failure resulting from the charging failure are suppressed.

  In the present embodiment, the irregularities of the surface layer 76 are arranged in a spiral shape wound in a reverse direction to the spiral of the cleaning material 66. For this reason, compared with the case where the unevenness | corrugation of the surface layer 76 is arrange | positioned in the spiral of the same winding direction as the spiral of the cleaning material 66, the unevenness | corrugation of the surface layer 76 is set to a spiral angle different from the spiral angle of the cleaning material 66. The degree of freedom of the set angle becomes high. For example, by setting a large angle difference between the spiral angle θ1 of the cleaning material 66 and the spiral angle θ2 of the unevenness of the surface layer 76, the amount of deformation of the cleaning material 66 is increased, and the cleaning performance of the cleaning material 66 is improved.

(Modification)
In 1st Embodiment, although the unevenness | corrugation of the surface layer 76 was made into the spiral of reverse winding with the spiral of the cleaning material 66, it is not restricted to this. If the spiral angle θ <b> 1 of the cleaning material 66 is different from the spiral angle θ <b> 2 of the unevenness of the surface layer 76, the unevenness of the surface layer 76 may be spiral in the same winding direction as the spiral of the cleaning material 66. That is, both the spiral angle θ1 of the cleaning material 66 and the spiral angle θ2 of the unevenness of the surface layer 76 may be acute angles.

Second Embodiment
Next, an image forming apparatus according to the second embodiment will be described. In addition, about the same part as 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted suitably.

  As shown in FIG. 6, the image forming apparatus 200 according to the second embodiment includes a charging roll 270 instead of the charging roll 70 in the first embodiment. Note that the configuration of the image forming apparatus 200 other than the charging roll 70 is the same as that of the image forming apparatus 10 according to the first embodiment.

  The charging roll 270 has a surface layer 276 instead of the surface layer 76 in the charging roll 70. The configuration of the charging roll 270 other than the surface layer 276 is the same as that of the charging roll 70.

  The surface layer 276 is arranged in a spiral shape that is swirled in a direction opposite to the spiral of the cleaning material 66 from one end side to the other end side in the rotational axis direction of the charging roll 270 (axial direction of the conductive support 72). It has a high and low part of the coefficient. Specifically, the high and low portions of the coefficient of friction are counterclockwise from the end on the bearing portion 82 side of the charging roll 270 toward the end portion (A direction) on the bearing portion 84 side as viewed in the direction A. They are arranged in a spiral shape.

  Thereby, the spiral angle θ1 of the cleaning material 66 is different from the spiral angle θ2 of the portion of the surface layer 276 where the friction coefficient is high or low.

  The spiral angle θ <b> 1 is an angle at which the axial direction Q <b> 1 of the shaft portion 64 and the length direction P <b> 1 of the cleaning material 66 intersect in the side view (the angle on the right side and the upper side in FIG. 6 when viewed from the intersection). In addition, the helical angle θ2 intersects the axial direction Q2 of the conductive support 72 in the side view (rotational axis direction of the charging roll 270) and the formation direction (length direction) P2 of the high and low portions of the friction coefficient in the surface layer 276. (The angle on the right side and the upper side in FIG. 6 when viewed from the intersection). The spiral angle θ1 is an obtuse angle, and the spiral angle θ2 is an acute angle.

  In the present embodiment, for example, the solid line portion in the figure is the low friction portion 270A, and the portion other than the solid line portion is the high friction portion 270B. The low friction portion 270A and the high friction portion 270B form a high and low portion of the friction coefficient in the surface layer 276. The high and low portions of the friction coefficient are set within a range where the influence of image quality such as charging unevenness is allowed.

  Specifically, the difference between the minimum value and the maximum value of the friction coefficient in the surface layer 276 (the difference in the friction coefficient between the low friction portion 270A and the high friction portion 270B) is 0.03 or more and 0.2 or less. Yes. Here, the friction coefficient is a dynamic friction coefficient, and a value measured by a Haydon type friction coefficient measuring machine (manufactured by Haydon) in an environment of a temperature of 22 ° C. and a humidity of 55% is used. More specifically, the dynamic friction coefficient is measured when the probe is brought into contact with the surface layer of the charging roll 270 and the probe is moved in the axial direction of the charging roll 270 at least twice the interval between the convex portions. The value and the minimum value were taken as the minimum value and the maximum value of the friction coefficient.

  The surface layer 276 is made of the same material as the surface layer 76. In addition, in the surface layer 76, addition of resin particles (resin filler) for adjusting the surface roughness (surface friction coefficient) was optional, but in the surface layer 276, it is essential at least in the high friction portion 270B. Resin particles (resin filler) are included as a component.

(Formation of surface layer 276)
The surface layer 276 is formed by dispersing each component of the surface layer 276 in a solvent to prepare a coating solution, applying the coating solution on the conductive elastic layer 74, and then heating.

  The solvent used for the coating solution is the same as that for the surface layer 27. Further, as a coating method of the coating solution, for example, a flow coating method using a coating apparatus 100 is used as in the case of the surface layer 27 (see FIG. 3).

  In the flow coating method, as in the case of the surface layer 27, the coating liquid 114 is applied to the outer peripheral surface of the conductive elastic layer 74 so as to overlap in the axial direction of the conductive support 72. This overlapping portion becomes the low friction portion 270A of the surface layer 276.

  The contact load of the blade 140 with respect to the conductive elastic layer 74 is set such that the overlapping portion of the coating liquid 114 remains as a convex portion. As a result, the blade 140 is moved along the axial direction of the conductive support 72 by the moving mechanism 150, and the coating liquid 114 applied to the outer peripheral surface of the conductive elastic layer 74 is left uneven. The liquid 114 is smoothed. Thereby, the coating film which has an unevenness | corrugation is formed. The surface layer 276 is formed by heating and drying the coating film.

  In the aforementioned overlapping portion, the coating film is relatively thick, and the time until the coating solution dries and hardens (the time that the coating solution continues to flow) is relatively long. On the other hand, except for the overlapping portion described above, the coating film is relatively thin, and the time until the coating liquid dries and hardens (the time during which the coating liquid continues to flow) is relatively short.

  For this reason, it is difficult for the resin particles to be exposed in the above-described overlapping portion, and the overlapping portion becomes the low friction portion 270 </ b> A of the surface layer 276. On the other hand, the resin particles can be easily exposed at portions other than the overlapping portions described above, and become the high and low friction portions 270B of the surface layer 276.

  Note that the method of forming the surface layer 276 having the high and low portions of the friction coefficient is not limited to the method described above. In the float coating method, for example, two discharge units 130 are arranged in the axial direction of the conductive support 72, and a coating liquid in which the dispersion amount of resin particles per unit liquid amount is changed spirally from each discharge unit 130. It may be applied to form a surface layer 276 having high and low portions of the coefficient of friction.

(Operation of this embodiment)
Next, the operation of this embodiment will be described.

  In the present embodiment, foreign substances such as developer remaining on the photoconductor 32 without being transferred to the intermediate transfer belt 24 are removed from the photoconductor 32 by the removing member 40. Part of the foreign matter such as a developer that has passed through the removing member 40 without being removed by the removing member 40 adheres to the surface of the charging roll 270 (see FIG. 1).

  The foreign matter adhering to the surface of the charging roll 270 contacts the charging roll 270 with the protrusion 66A and the outer peripheral surface of the cleaning material 66, and the outer peripheral surface of the cleaning material 66 wipes the outer peripheral surface of the charging roll 270 and cleans it. The protrusion 66A of the material 66 is removed by scraping off the foreign matter.

  Specifically, as shown in FIGS. 7A and 7B, the foreign matter adhering to the outer peripheral surface of the charging roll 270 rotating in one direction (counterclockwise in FIG. 7) is driven by the cleaning member 60 that rotates in a driven manner. The protrusion 66A of the cleaning material 66 is pushed by the outer peripheral surface of the charging roll 270, and the height direction of the cleaning material 66 (G direction shown in FIG. 7A) and the width direction (H shown in FIG. 7A). The elastic material is elastically deformed (elastically compressed) in the direction, and is pushed and aggregated by the cleaning material 66. Then, as shown in FIG. 7C, the aggregated foreign substances such as external additives are more dense than the restoring force by restoring the charging roll 270 in the cleaning material 66 of the cleaning member 60 that is driven to rotate. They are loosened from the state or repelled from the outer peripheral surface of the charging roll 270.

  Here, in this embodiment, the spiral angle θ1 of the cleaning material 66 is different from the spiral angle θ2 of the portion of the surface layer 276 where the friction coefficient is high or low. As a result, when the charging roll 270 and the cleaning member 60 rotate, the low friction portions 270A and the high friction portions 270B of the surface layer 276 alternately cross (intersect) the protrusions 66A along the longitudinal direction of the cleaning material 66. ). Accordingly, the protrusions 66A of the cleaning material 66 alternately contact the low friction portions 270A and the high friction portions 270B. As a result, the cleaning material 66 repeatedly slips (stops) and stops (stops) with respect to the surface of the charging roll 270 (stick-slip phenomenon), and the spiral angle θ1 of the cleaning material 66 and the friction coefficient at the surface layer 276 are increased or decreased. Compared with the case where the helical angle θ2 of the portion is the same, the deformation amount of the protrusion 66A increases. For this reason, the scraping performance by which the protrusion 66A of the cleaning material 66 scrapes off the foreign matter is improved.

  That is, according to the configuration of the present embodiment, the cleaning performance of the cleaning material 66 is improved as compared with the case where the spiral angle θ1 of the cleaning material 66 is the same as the height portion of the friction coefficient in the surface layer 276. As a result, the charging failure caused by the cleaning failure of the charging roll 270 and the image failure caused by the charging failure are suppressed.

  In the present embodiment, the difference between the minimum value and the maximum value of the friction coefficient in the surface layer 276 (difference in friction coefficient between the low friction portion 270A and the high friction portion 270B) is 0.03 or more and 0.2 or less. Has been. For this reason, compared with the case where the difference between the minimum value and the maximum value of the friction coefficient in the surface layer 276 is less than 0.03, the cleaning material 66 slips (slides) and stops (stops) with respect to the surface of the charging roll 270. Phenomenon is likely to occur, and as described above, the scraping performance of the protruding portion 66A of the cleaning material 66 to scrape foreign matter is improved. That is, the cleaning performance of the cleaning material 66 is improved as compared with the case where the difference between the minimum value and the maximum value of the friction coefficient in the surface layer 276 is less than 0.03. As a result, the charging failure caused by the cleaning failure of the charging roll 270 and the image failure caused by the charging failure are suppressed.

  Further, as compared with the case where the difference between the minimum value and the maximum value of the friction coefficient in the surface layer 276 exceeds 0.2, streaky charging unevenness due to the difference in the friction coefficient (surface roughness) in the surface layer 276 is suppressed. Is done. Thereby, the image defect resulting from the charging failure is suppressed.

  In the present embodiment, the high and low portions of the friction coefficient in the surface layer 276 are arranged in a spiral shape wound in a reverse direction to the spiral of the cleaning material 66. For this reason, compared with the case where the high and low portions of the friction coefficient in the surface layer 276 are arranged in a spiral shape in the same winding direction as the spiral of the cleaning material 66, the high and low portions of the friction coefficient in the surface layer 276 are compared with the spiral of the cleaning material 66. The degree of freedom of the set angle when setting a spiral angle different from the angle is increased. For example, by setting a large angle difference between the spiral angle θ1 of the cleaning material 66 and the spiral angle θ2 of the high and low friction coefficient in the surface layer 276, the deformation amount of the cleaning material 66 is increased, and the cleaning performance of the cleaning material 66 is increased. Will improve.

(Modification in the second embodiment)
In the second embodiment, the high and low portions of the friction coefficient in the surface layer 276 are formed in a spiral shape that is reverse to the spiral of the cleaning material 66, but is not limited thereto. If the spiral angle θ1 of the cleaning material 66 is different from the spiral angle θ2 of the high and low friction coefficient portion of the surface layer 276, the high and low portion of the friction coefficient of the surface layer 276 is in the same winding direction as the spiral of the cleaning material 66. It may be spiral. That is, both the spiral angle θ1 of the cleaning material 66 and the spiral angle θ2 of the high and low portion of the friction coefficient in the surface layer 276 may be acute angles.

<Modifications in the first and second embodiments>
In the first embodiment and the second embodiment described above, the charging rolls 70 and 270 are used as the objects to be cleaned. However, the present invention is not limited to this. The object to be cleaned may be a photoconductor (image carrier) or a transfer roll (for example, the first transfer roll 26 or the second transfer roll 28).

  In the first embodiment and the second embodiment described above, the cleaning material 66 is composed of a single spiral, but as shown in FIG. 8, it may be composed of a double spiral, or a plurality of spirals. It may be comprised.

  The present invention is not limited to the above-described embodiment, and various modifications, changes, and improvements can be made without departing from the spirit of the present invention. For example, the modification examples described above may be appropriately combined.

  Hereinafter, examples according to the second embodiment will be specifically described. However, the present invention is not limited to these examples.

<Example 1>
(Preparation of charging roll 270)
-Formation of conductive elastic layer 74-
・ Epichlorohydrin rubber (Gechron 3106, manufactured by Nippon Zeon Co., Ltd.) 100 parts by mass ・ Carbon black (Asahi # 60, manufactured by Asahi Carbon Co., Ltd.) 6 parts by mass ・ Calcium carbonate (Whiteon SB, manufactured by Shiraishi Calcium Co., Ltd.) 20 parts by mass Conductive agent (BTEAC, manufactured by Lion Corporation) 5 parts by mass, vulcanization accelerator: stearic acid (manufactured by NOF Corporation) 1 part by mass, vulcanizing agent: sulfur (Parnock R, manufactured by Ouchi Shinsei Chemical Co., Ltd.) 1 part by mass Vulcanization accelerator: 1.5 parts by mass of zinc oxide

  A mixture having the composition shown above is kneaded with an open roll, and a roll having a diameter of 15 mm is formed on the surface of a metal shaft (conductive support 72) having a diameter of 8 mm formed of SUS303 using a press molding machine through an adhesive layer. A shaped elastic layer was formed. The elastic layer was polished to obtain a conductive elastic layer 74.

-Formation of surface layer 276-
Binder resin: N-methoxymethylated nylon (trade name F30K, manufactured by Nagase ChemteX Corporation)
100 parts by mass / conductive agent: carbon black (trade name: MONAHRCH1000, manufactured by Cabot Corporation)
15 parts by mass / resin particles (resin filler): polyamide particles (polyamide 12, manufactured by Arkema)
20 parts by mass

  A dispersion obtained by diluting the mixture having the above composition with methanol and dispersing with a bead mill was applied to the outer peripheral surface of the conductive elastic layer 74 by the flow coating method using the above-described coating apparatus 100. At this time, the rotation speed of the rotating unit 120 of the coating apparatus 100 was set to 1000 rpm, and the moving speed of the discharge unit 130 was set to 43 mm / sec.

  And the obtained coating film was heat-dried at 130 degreeC for 30 minute (s), and the 9-micrometer-thick surface layer 276 which has the high and low part of a friction coefficient was formed. The difference between the minimum value and the maximum value of the friction coefficient in the surface layer 276 (difference in friction coefficient between the low friction portion 270A and the high friction portion 270B) is adjusted to 0.1.

(Preparation of cleaning member 60)
A 2.5 mm thick urethane foam (EP-70: manufactured by Inoac Corporation) sheet is attached to a 0.15 mm thick double-sided tape (4801-015; manufactured by Sumitomo 3M), and the sheet is 10 mm in width and length. It cut out so that it might become a 370-mm strip. Place the obtained strip on a horizontal table so that the release paper affixed to the double-sided tape faces downward, and use stainless steel heated from the top to make a strip (a strip composed of polyurethane foam excluding double-sided tape) The total thickness was 8%.

  Next, the strip after compression is wound around a metal shaft (outer diameter: 6 mm, total length: 331 mm) as the shaft portion 64 in a spiral shape reverse to the spiral of the surface layer 276 where the friction coefficient is high or low. Formed.

  In Example 1, as described above, the difference between the minimum value and the maximum value of the friction coefficient in the surface layer 276 (the difference in friction coefficient between the low friction portion 270A and the high friction portion 270B) is adjusted to 0.1. ing.

<Example 2>
In Example 2, the difference between the minimum value and the maximum value of the friction coefficient in the surface layer 276 (the difference in friction coefficient between the low friction portion 270A and the high friction portion 270B) is adjusted to 0.03. Other configurations are the same as those in the first embodiment.

<Example 3>
In Example 3, the difference between the minimum value and the maximum value of the friction coefficient in the surface layer 276 (the difference in friction coefficient between the low friction portion 270A and the high friction portion 270B) is adjusted to 0.2. Other configurations are the same as those in the first embodiment.

<Example 4>
In Example 4, the difference between the minimum value and the maximum value of the friction coefficient in the surface layer 276 (the difference in friction coefficient between the low friction portion 270A and the high friction portion 270B) is adjusted to 0.02. Other configurations are the same as those in the first embodiment.

<Example 5>
In Example 5, the difference between the minimum value and the maximum value of the friction coefficient in the surface layer 276 (the difference in friction coefficient between the low friction portion 270A and the high friction portion 270B) is adjusted to 0.3. Other configurations are the same as those in the first embodiment.

<Example 6>
In Example 6, the difference between the minimum value and the maximum value of the friction coefficient in the surface layer 276 (the difference in friction coefficient between the low friction portion 270A and the high friction portion 270B) is adjusted to 0.1. Further, in Example 6, the spiral of the cleaning material 66 and the spiral of the high and low portions of the friction coefficient in the surface layer 276 are in the same winding direction, and the spiral angle θ1 of the cleaning material 66 and the high and low portion of the friction coefficient in the surface layer 276 are. There is an angle difference of 25 degrees from the spiral angle θ2. Other configurations are the same as those in the first embodiment.

<Comparative Example 1>
In Comparative Example 1, the difference between the minimum value and the maximum value of the friction coefficient in the surface layer 276 (the difference in friction coefficient between the low friction portion 270A and the high friction portion 270B) is adjusted to 0.1. The spiral of the cleaning material 66 and the spiral of the high and low portions of the friction coefficient in the surface layer 276 have the same winding direction, and the helical angle θ1 of the cleaning material 66 and the helical angle θ2 of the high and low portions of the friction coefficient of the surface layer 276 are the same. It is an angle. Other configurations are the same as those in the first embodiment.

<Comparative example 2>
In the comparative example, a cylindrical cleaning material is used instead of the spiral cleaning material 66. Specifically, a hole of Φ5mm is drilled in a square material of urethane foam (EPM-70; manufactured by Inoac Corporation), and a metal shaft (outer diameter 6 mm, total length 331 mm) coated with an adhesive is inserted. Thereafter, the urethane foam was polished into a cylindrical shape. Other configurations are the same as those in the first embodiment.

[Evaluation of cleaning performance]
The cleaning performance was evaluated based on whether or not density unevenness of the image due to charging failure caused by cleaning failure occurred. Specifically, the charging device manufactured as described above is incorporated into a modified DocuCentre505a machine, 150,000 image quality patterns with an average image density of 5% are printed on A4 paper, and then a halftone image with a density of 30% is 1 It was done by outputting a sheet. The obtained halftone image having a density of 30% was visually evaluated based on the following indices.
A: Density unevenness does not occur B: Density unevenness occurs slightly (a level that causes no problem in practical use)
C: Density unevenness occurs (level at which there is a practical problem)

[Evaluation of image quality]
The image quality was evaluated based on whether or not a streak-like image defect due to a difference in friction coefficient (surface roughness) of the surface layer 276 in the charging roll 270 occurred. Specifically, the charging device manufactured as described above is incorporated into a modified DocuCentre505a machine, 150,000 image quality patterns with an average image density of 5% are printed on A4 paper, and then a halftone image with a density of 30% is 1 It was done by outputting a sheet. The obtained halftone image having a density of 30% was visually evaluated based on the following indices.
A: No streak-like image defect occurs B: Slight-like image defect occurs slightly (a level that causes no problem in practical use)

  As a result, as shown in FIG. 9, in Examples 1 to 3, density unevenness did not occur, and no streak-like image defect occurred. In Examples 4 and 6, density unevenness occurred, but at a level where there was no practical problem, and no streak-like image defect occurred. In Example 5, density unevenness did not occur and a streak-like image defect occurred, but it was at a level with no practical problem. In Comparative Examples 1 and 2, density unevenness occurred and there was a practical problem. From the above, it can be seen that this example has better cleaning performance than the comparative example.

10 Image forming apparatus 32 Photosensitive member (an example of an image carrier, an example of an object to be charged)
64 Shaft 66 Cleaning material 70, 270 Charging roll (an example of an object to be cleaned, an example of a charged body)
76, 276 Surface layer

Claims (7)

A rotating object to be cleaned;
A shaft portion disposed along the rotational axis direction of the object to be cleaned;
A cleaning material that is spirally arranged from one end side to the other end side in the axial direction of the shaft portion on the outer peripheral surface of the shaft portion, and is in contact with the outer peripheral surface of the object to be cleaned,
The cleaning target has an unevenness formed on the outer peripheral surface of the object to be cleaned from one end side to the other end side in the rotation axis direction and arranged in a spiral shape with a spiral angle different from the spiral angle of the cleaning material, A surface layer in contact with the material;
Cleaning structure comprising.   The unevenness | corrugation of the said surface layer is a cleaning structure of Claim 1 arrange | positioned at the spiral shape reversely wound with the spiral of the said cleaning material. A rotating object to be cleaned;
A shaft portion disposed along the rotational axis direction of the object to be cleaned;
A cleaning material that is spirally arranged from one end side to the other end side in the axial direction of the shaft portion on the outer peripheral surface of the shaft portion, and is in contact with the outer peripheral surface of the object to be cleaned,
Formed on the outer peripheral surface of the object to be cleaned from one end side to the other end side in the rotational axis direction, and has a high and low portion of the coefficient of friction arranged in a spiral shape with a spiral angle different from the spiral angle of the cleaning material. And a surface layer in contact with the cleaning material;
Cleaning structure comprising. The object to be cleaned is a charged body that charges the object to be charged,
The cleaning structure according to claim 3, wherein a difference between a minimum value and a maximum value of the friction coefficient in the surface layer is 0.03 or more and 0.2 or less.   The charging device having the cleaning structure according to claim 1, further comprising a charging member that charges the member to be cleaned as the member to be cleaned. An image carrier capable of holding an image;
The cleaning structure according to claim 1, wherein the cleaning target includes a charging body that charges the image holding body.
Is an assembly that is assembled to the main body of the apparatus so as to be detachable. An image carrier capable of holding an image;
The cleaning structure according to claim 1, wherein the cleaning target includes a charging body that charges the image holding body.
An image forming apparatus comprising:

Images