JP6524710B2 - Fixing device and image forming apparatus - Google Patents

Description

  The present invention relates to a fixing device and an image forming apparatus.

  As an invention of a fixing device, for example, in the following Patent Document 1, a rotatable endless fixing member, a heat source for heating the fixing member, and an outer peripheral side of the fixing member are disposed in a pressure contact with the fixing member. A pressing member, a nip forming member disposed on the inner peripheral side of the fixing member and in pressure contact with the pressing member via the fixing member to form a nip portion, and fixed to an inner diameter portion of the fixing member A fixing member including a reinforcing member supporting the nip forming member from the side opposite to the nip portion, and a sliding sheet is provided between the nip forming member and the inner circumferential surface of the fixing member, A fixing device is disclosed in which the sliding sheet is held in close contact with the surface on the nip portion side of the nip forming member by holding means provided on a member different from the nip forming member. There is.

  Further, a fixing device for fixing a toner image carried on a recording medium is disclosed in the following Patent Document 2, and the surface is elastically deformed and a rotating member which is rotationally driven and an endless member which is in contact with the rotating member. A fixing belt formed in a belt shape, and a soft pad member that is inside the fixing belt and applies a predetermined pressure to the rotating member by pressing the rotating member via the fixing belt; A pad member main body having a plurality of locking pieces protruding in a projecting shape respectively at a plurality of linear positions along the longitudinal direction and being inside the fixing belt and supporting the soft pad member; The plurality of engagement holes are respectively inserted and engaged in the engagement pieces, and are wound around the pad member main body so as to cover the soft pad member so as to face the fixing belt. A low friction sheet member to be placed, a lubricant application member that is in sliding contact with the inner circumferential surface of the fixing belt to replenish the lubricant, and a clearance groove for loosely inserting the locking piece are formed. A holder member for supporting the pad member main body and supporting the lubricant application member on the side opposite to the pad member main body, and the low friction sheet member is made of a woven fabric of weft yarn and warp yarn A fixing device for an electrophotographic system is disclosed.

JP, 2014-048487, A JP, 2010-282237, A

  An object of the present invention is to provide a fixing device and an image forming apparatus capable of preventing the sliding member from coming off.

  The fixing device according to claim 1 of the present invention includes a rotating body, an endless strip that contacts the rotating body to form a contact area, a heating source that heats the contact area, and the inside of the endless strip. A holder for rotatably holding the endless band, and a sliding member provided between the endless band and the holder for sliding movement of the endless band, and the holder A convex portion is formed on one of the sliding members, and a concave portion is formed on the other, and the convex portion and the concave portion are fitted to each other, and the sliding member is fixed to the holding body. And a fixing device having a preventing member for preventing disengaging with the fixing device.

  In the fixing device according to claim 2 of the present invention, the preventing member is impregnated with a lubricant, and the fixing according to claim 1, wherein the inner surface side of the endless strip is in contact with the preventing member. It is an apparatus.

  The fixing device according to a third aspect of the present invention is the fixing device according to the first or second aspect, wherein the preventing member is in contact with the tip end side of the convex portion.

  The fixing device according to a fourth aspect of the present invention is the fixing device according to the fourth aspect, wherein the first height of the preventing member and the convex portion of the holder adjacent to the preventing member are formed in the radial direction of the endless strip. The fixing device according to any one of claims 1 to 3, wherein the first height of the preventing member is higher when comparing a second height obtained by combining the thickness of the sliding member with the thickness of the sliding member. is there.

  In the fixing device according to a fifth aspect of the present invention, in the endless belt-like member, a portion where the convex portion of the holding body adjacent to the preventing member is formed and a thickness of the sliding member are matched. The fixing device according to any one of claims 1 to 4, which is apart from the image forming apparatus.

  A fixing device according to claim 6 of the present invention is an image forming apparatus provided with the fixing device according to any one of claims 1 to 5.

  According to the first aspect of the present invention, the sliding member can be prevented from coming off.

  According to the second aspect of the present invention, in addition to the effects of the first aspect of the present invention, a lubricant can be supplied to the endless belt.

  According to the third aspect of the present invention, in addition to the effect of the present invention according to the first or second aspect, it is possible to prevent the prevention member from being deformed by the rotation of the endless strip.

  According to the fourth aspect of the present invention, in addition to the effect of the present invention according to any one of the first to third aspects, the endless belt-like member is a part where the convex portion and the sliding member are attached to the convex portion. Damage to the endless belt and the sliding member can be prevented.

  According to the fifth aspect of the present invention, in addition to the effect of the fourth aspect of the present invention, it is possible to prevent the tensile force by the endless belt from being directly applied to the portion attached to the convex portion of the sliding member. it can.

  According to the sixth aspect of the present invention, it is possible to obtain an image forming apparatus provided with the fixing device having the effect of the present invention according to any one of the first to fifth aspects.

FIG. 1 is a side cross-sectional view showing an image forming apparatus according to an embodiment. FIG. 2 is a side cross-sectional view showing the fixing device according to the embodiment. FIG. 3 is a side cross-sectional view showing a pressure unit of the fixing device according to the embodiment. It is an expanded sectional view of the IV section of FIG. It is a perspective view of a pressurization part concerning an embodiment. FIG. 6A is a front view of the sliding member, and FIG. 6B is an enlarged front view of a part of the pressing portion.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiment shown below is an example of a fixing device and an image forming apparatus for embodying the technical concept of the present invention, and is not intended to specify the present invention thereto, and a patent It is equally applicable to the other embodiments included in the claims.

[Embodiment]
An image forming apparatus 10 according to the embodiment will be described with reference to FIGS. 1 to 6. As shown in FIG. 1, the image forming apparatus 10 according to the embodiment has an image forming apparatus main body 12, and at least one sheet feeding unit 18 and an image forming unit 14 inside the image forming apparatus main body 12. A transport path 32 is provided which has a fixing device 36 mounted thereon, an outlet 34 at the upper portion of the image forming apparatus main body 12, and a recording medium 130 such as a recording sheet as a material to be transferred so as to communicate them. It is done. Further, as described later, in the image forming apparatus 10 according to the embodiment, Free Belt Nip Fusing (FBNF) is pressed by two different pressing forces by the pressing unit 76 provided in the fixing device 36. ) Has the configuration of the method). Each component will be described below.

  The sheet feeding unit 18 includes a sheet feeding unit main body 20, a sheet feeding cassette 22 in which a recording medium 130 as a material to be transferred is stored, a pickup roll 24 for drawing out the recording medium 130 stacked on the sheet feeding cassette 22, A feed roll 28 and a retard roll 26 are disposed to feed the sheet while looking through the sheet. By rotation of the pickup roll 24, the feed roll 28 and the retard roll 26, the recording medium 130 stacked on the sheet feeding cassette 22 is conveyed along the conveyance path 32 to a resist roll 38 described later. The sheet feeding cassette 22 is detachably attached to the sheet feeding unit main body 20. Further, the number of sheet feeding units may be one or plural, but in the embodiment, two sheet feeding units 18 are provided as shown in FIG.

  The image forming unit 14 is an electrophotographic type, and the image carrier 44 made of a photosensitive member, the charging device 56 for uniformly charging the image carrier 44, for example, a charging roll, and the charging device 56 And a developing device 60 having a developing roll for visualizing the latent image of the image carrier 44 formed by the optical writing device 58 with toner on the image carrier 44 with light. A transfer device 42 comprising, for example, a transfer roll for transferring a toner image by the developing device 60 to the recording medium 130, a cleaning device 62 for cleaning toner remaining on the image carrier 44, and a recording medium transferred by the transfer device 42. A fixing device 36 fixes the upper toner image to a recording medium.

  The optical writing device 58 is, for example, a scanning type laser exposure device, traverses a process cartridge 64 described later, and forms a latent image on the image carrier 44. The optical writing device 58 may use an LED, a surface emitting laser, or the like as another embodiment.

  The process cartridge 64 is an integral unit of the image carrier 44, the charging device 56, the developing device 60, and the cleaning device 62, and these can be replaced as one piece. The process cartridge 64 can be removed from the image forming apparatus main body 12 by opening the discharge unit 16.

  The conveyance path 32 is a passage of the recording medium 130 communicated from the pickup roll 24 of the sheet feeding unit 18 in the lower part of the image forming apparatus main body 12 to the discharge port 34 in the upper part of the image forming apparatus main body 12. The conveyance path 32 is inside the image forming apparatus main body 12 and has a portion formed substantially vertically from the pickup roll 24 of the lower paper feed unit 18 to the fixing device 36.

  A transfer device 42 and an image carrier 44 are disposed upstream of the fixing device 36 of the transport path 32, and a resist roll 38 is disposed upstream of the transfer device 42 and the image carrier 44. Further, a discharge roll 40 is disposed in the vicinity of the discharge port 34 of the conveyance path 32.

  Accordingly, the recording medium 130 delivered by the pickup roll 24 from the sheet feeding cassette 22 of the sheet feeding unit 18 is rolled by the retard roll 26 and the feed roll 28 and guided to the conveyance path 32 and temporarily stopped by the registration roll 38. At a timing, the developer image is transferred between the transfer device 42 and the image carrier 44, the transferred developer image is fixed by the fixing device 36, and the discharge roll 40 discharges the sheet by the discharge roller 40. It will be discharged to 16.

  Further, as shown in FIG. 2 to FIG. 6, the fixing device 36 can rotate the endless belt 72 as an endless belt 72 as an endless belt and a heating roller 66 as a rotating body having a heating source (heater). And a pressing unit 76 disposed inside the endless belt 72 and pressing the endless belt 72 toward the heating roller 66.

  The heating roll 66 has a cylindrical roll portion 84 and a heater 86 disposed in the roll portion 84. The roll portion 84 is rotatably supported by a heating roll bearing (not shown) so as to rotate in the arrow A direction (see FIG. 2). In addition, the roll portion 84 is a so-called hard roll which is composed of a core 88 made of a metal material such as iron, stainless steel or aluminum, and a release layer 90 coated or coated on the core 88 and does not have an elastic layer. It has become. The core 88 has an outer diameter of, for example, 25 mm and a wall thickness of, for example, 0.7 mm. The release layer 90 is made of an insulating material having excellent releasability, such as PFA, and has a film thickness of, for example, 20 μm.

  A plurality of (for example, five) peeling claws 92 are in contact with the roll portion 84. The heater 86 as a heating source is composed of, for example, two lamps. Further, on the opposite side of the heating roll 66 to the endless belt 72, a thermostat 94 is provided to face the heating roll 66.

  The heating roll may have a so-called flare shape. In the case of the flare shape, the recording medium is conveyed while being pulled to both ends, so the pressing width for pressing the both ends in the axial direction of the heating roll becomes wider than the central part, and the recording medium is picked up from both ends. Wrinkles and the like can be suppressed.

  The endless belt 72 is provided between the heating roller 66 and the pressing unit 76, and travels in the direction of arrow C following the rotation of the heating roller 66 (see FIG. 2). A contact area 102 is formed by pressure contact of the heating roller 66 and the endless belt 72 by the pressure unit 76, and the toner image is fixed on the recording medium 130 by the contact area 102. The endless belt 72 is formed of, for example, a synthetic resin such as polyimide in the form of an endless belt having a thickness of 75 μm, for example, and a release layer made of PFA or the like is provided on the surface.

  An inlet chute 96 is provided upstream of the contact area 102. The recording medium 130 conveyed in the arrow B direction is guided to the inlet chute 96, and the leading end of the recording medium 130 is guided to the contact area 102 (see FIG. 2). Also, an outlet chute 98 is provided downstream of the contact area 102.

  As shown in FIGS. 2 to 6, the pressure unit 76 supports the holding body 100 disposed inside the endless belt 72, the pressure member 122 attached to the holding body 100, and a frame for supporting the holding body 100. 78, 79, provided between the endless belt 72 and the holder 100, for preventing the sliding member 124 from coming off, and the sliding member 124 for reducing the friction between the endless belt 72 and the holder 100 A prevention member 128 is provided.

  Further, in the contact region 102 of the pressing unit 76 formed by being pressed by the heating roller 66, a pressing portion 104 formed on the holding body 100 described later and a pressing member 122 attached to the holding body 100 It is formed by being pressed by the heating roller 66. The pressing unit 76 is configured such that the holding body 100 and the frames 78 and 79 cooperate with each other to press the pressing portion 104 and the pressing member 122 together with the holding body 100 toward the heating roller 66.

  The holder 100 is formed of a resin material, for example, LCP (liquid crystal polymer) having high heat resistance. As shown in FIGS. 2 and 3, the holding body 100 includes a pressure portion 104 forming the contact area 102 on the side facing the heating roller 66, and a pressure member forming the contact area 102 together with the pressure portion 104. And a seating surface 106 to which 122 is attached.

  The pressing portion 104 is formed such that the side of the holding body 100 in contact with the heating roll 66 protrudes toward the heating roll 66 along the longitudinal direction, and is provided on the downstream side of the endless belt 72 in the rotation direction.

  The seating surface 106 is formed in a groove shape that is recessed along the longitudinal direction of the holding body 100, and is provided on the upstream side of the endless belt 72 in the rotation direction than the pressing portion 104. Then, the pressure member 122 is attached to the groove-like recess of the seating surface 106.

  Further, an extending portion 108 extending in the direction opposite to the rotation direction of the endless belt 72 is formed in the holding body 100 in the longitudinal direction of the holding body 100. On the opposite side to the side facing the roll 66, a plurality of convex portions 114 to which the sliding member 124 is attached, and a preventing member arranging portion 120 in which a preventing member 128 provided along the longitudinal direction of the holder 100 is disposed. Have.

  Furthermore, the extension portion 108 of the holding body 100 has a bottom surface portion 118 provided with the preventing member disposition portion 120, and a stepped step portion 110 formed to be higher than the bottom surface portion 118. have. The stepped portion 110 has a wall surface portion 112 formed in a wall shape from the bottom surface portion 118.

  The plurality of convex portions 114 are formed such that the rod-like body protrudes from the opposite side of the holding body 100 to the side facing the heating roller 66, that is, the back side of the contact region 102 of the holding body 100. The plurality of convex portions 114 are respectively formed on the wall surface portion 112 of the step portion 110 formed in the extension portion 108 so as to protrude in the direction opposite to the rotation direction of the endless belt 72. In the embodiment, the case where the number of convex portions is four is shown. However, the number is not limited to this and may be an arbitrary number.

  Further, the bottom surface portion 118 of the extension portion 108 is provided with a prevention member disposition portion 120 in which the prevention member 128 is disposed. The preventing member disposing portion 120 is positioned such that the preventing member 128 to be attached is in contact with the end portions 116 of the plurality of convex portions 114.

  The pressing member 122 is formed by bending a metal plate having a length substantially the same as the length of the holding body 100 in the longitudinal direction, and is formed in a spring shape having an elastic force. The pressure member 122 is attached to the seat 106 formed on the holder 100. At this time, the pressure member 122 is attached so that the bent side is disposed upstream of the endless belt 72 in the rotational direction. The pressing member 122 may have a plurality of slits formed in the direction orthogonal to the longitudinal direction. In addition, the pressing member may be a pressing pad formed of a resin material.

  The sliding member 124 is formed in a sheet shape as shown in FIGS. 5 and 6A, and is provided between the endless belt 72 and the holder 100, and the sliding surface is the inner circumferential surface of the endless belt 72 It is wound around the holder 100 so as to be in contact with it. The sliding member 124 is formed of, for example, a sheet-like member having a smooth surface such as polyimide, and is embossed by embossing on a portion of the sliding member 124 pressed against the pressure portion 104 and the heating roller 66. It may be formed.

  On one end side of the sliding member 124, a plurality of concave portions 126 which are opened so as to insert a plurality of convex portions 114 formed on the holding body 100 are formed. The concave portion 126 is oval in FIG. 6A, but may be another shape such as rectangular or circular so as to correspond to the shape of the convex portion formed on the holder.

  The other end of the sliding member 124 is a free end. Note that the length of the sliding member 124 is such that it extends at least beyond the contact area 102 toward the downstream side in the rotational direction when wound around the holding body 100.

  As shown in FIGS. 3 to 6, the preventing member 128 has a length substantially the same as the length of the holding body 100 in the longitudinal direction, and is formed of a rod-like body having a rectangular cross section. Further, the preventing member 128 is impregnated with a lubricant, and the lubricant is supplied between the sliding member 124 and the endless belt 72. Therefore, the preventing member 128 is formed of a material that can be impregnated with a lubricant, for example, a fiber material such as felt.

  The slide member 124 and the prevention member 128 are attached to the holder 100 by first forming a plurality of concave portions 126 formed on one end side of the slide member 124 on the plurality of convex portions 114 formed on the holder 100. Fit and fix. (Here, “fixing” also includes a state in which movement is possible only in a certain area.) Thereafter, the prevention member disposition portion 120 of the holder 100 is held in contact with the tip portions 116 of the plurality of convex portions 114. Attach prevention member 128 along the longitudinal direction of body 100. Then, the other end side of the sliding member 124 is wound around the holder 100 (see FIGS. 5 and 6B).

  Further, in the radial direction of the endless belt, a first height of the prevention member 128 attached to the holder 100 and a portion adjacent to the prevention member 128 of the step portion 110 of the holder 100, that is, a convex portion 114 is formed. When a second height obtained by combining the upper portion 111 of the wall portion 112 and the thickness of the sliding member 124 wound around the upper portion 111 of the wall portion 112 is compared, as shown in FIG. The first height of 128 is intended to be higher.

  As shown in FIGS. 2 and 5, the guide members 74 are disposed at both ends of the endless belt 72 and the pressing unit 76, and the pressing unit 76 is supported by the guide members 74.

  As shown in FIGS. 2 and 5, the frames 78, 79 support the holder 100, and both ends thereof are supported by the guide member 74 so that the holder 100 is pressed to the heating roller 66 side. There is. At this time, the ends of the frames 78 and 79 pass through the guide member 74, and the ends of the frames 78 and 79 are biased toward the heating roller 66 by biasing means such as a spring. At this time, a pressing lever is connected to a member for supporting the pressing unit 76, and the pressing lever is biased such that the pressing unit 76 presses the heating roller 66 by biasing means. (Not shown).

  Here, fixing of the toner image on the recording medium by the fixing device 36 of the image forming apparatus 10 of the embodiment will be described mainly with reference to FIGS. 2 and 3. In fixing the toner image on the recording medium 130 by the fixing device 36, first, the recording medium 130 to which the toner image is transferred by the image forming unit 14 passes the conveyance path 32, and the heating roller 66 and the endless belt 72 are pressed. It is fed to the contact area 102 pressed by the pressing member 122 and the pressing portion 104 of the pressing portion 76. At this time, the heating roller 66 is rotationally driven, and the recording medium 130 is fed to the contact area by the endless belt 72 also rotating around the outer periphery of the pressing unit 76 following the rotation. The leading end of the fed recording medium 130 is sandwiched between the heating roll 66 and the endless belt 72, and is first pressed against the heating roll 66 and the pressing member 122, and then the heating roll 66 and the pressing portion The toner image is fixed to the recording medium 130 by being pressed by 104.

  At this time, the pressing force for pressing the heating roller 66 is pressed so that the pressing force of the pressing portion 104 becomes stronger than that of the pressing member 122. That is, the pressing of the recording medium 130 by the pressing member 122 and the pressing portion 104 is performed first after the pressing force provided on the inlet side 68 of the recording medium 130 is pressed by the weak pressing member 122 and then the pressing force is strong. It is pressed by the pressing portion 104. At this time, although the pressure member 122 on the inlet side 68 and the pressure portion 104 on the outlet side 70 are pressed by the biasing force of the biasing means of the pressure portion 76, the pressure member 122 can be elastically deformed. While the pressure portion 104 is formed integrally with the holder 100 while being formed of a plate, it is difficult to deform. Therefore, the pressing force of the pressing member 122 on the inlet side 68 is pressed by a weaker pressing force than the pressing portion 104 on the outlet side 70.

  In addition, when the endless belt 72 rotates following the rotation of the heating roll 66, the endless belt 72 is smoothly rotated by the sliding member 124 provided between the holding body 100 and the endless belt 72. At this time, the endless belt 72 rotates in contact with the preventing member 128 provided on the holder 100, and the preventing member 128 is impregnated with a lubricant, so the sliding member 124 and the endless belt 72 are in contact with each other. The lubricant is retained between the inner circumferential surface and the inner circumferential surface.

  Further, as described above, the first height of the preventing member 128 attached to the holder 100 and the portion of the holder 100 adjacent to the preventing member 128, that is, the wall surface on which the convex portion 114 of the holder 100 is formed. The height of the preventing member 128 is higher when the second height obtained by combining the upper portion 111 of the portion 112 and the thickness of the sliding member 124 wound around the upper portion 111 of the wall portion 112 is compared. (See Figure 4). Therefore, the endless belt 72 rotates in a floating state on the upper portion 111 of the wall surface portion 112 of the holder 100 and the concave portion 126 attached to the convex portion 114 of the sliding member 124. Therefore, deformation of the endless belt and the sliding member is prevented. Further, by increasing the first height of the preventing member 128, the sliding member 124 comes into contact with the endless belt 72 at a position separated from the position where the convex portion 114 of the holding body 100 is formed. The tensile force by the endless belt 72 is not directly applied to the concave portion 126 of the sliding member 124 attached to the convex portion 114.

  Further, the prevention member 128 is provided in contact with the end portions 116 of the plurality of convex portions 114 of the holding body 100, whereby the prevention member 128 is prevented from being deformed by the rotation of the endless belt 72.

  In the embodiment, the convex portion is formed on the holding body and the concave portion is formed on the sliding member. However, the present invention is not limited to this. The concave portion is formed on the holding body and the convex portion is formed on the sliding member You may

10: image forming apparatus 12: image forming apparatus main body 14: image forming means 16: discharge unit 18: paper feed unit 20: paper feed unit main body 22: paper feed cassette 24: pickup roll 26: retard roll 28: feed roll 32: feed roll 32: Conveying path 34: discharge port 36: fixing device 38: resist roll 40: discharge roller 42: transfer device 44: image carrier 56: charging device 58: light writing device 60: developing device 62: cleaning device 64: process cartridge 66: Heating roll 68: inlet side 70: outlet side 72: endless belt 74: guide member 76: pressure part 78, 79: frame 84: roll part 86: heater 88: core 90: release layer 92: peeling nail 94: thermostat 96: Inlet chute 98: Outlet chute 100: Holding body 10 : Contact area 104: Pressed part 106: Seat surface 108: Extension part 110: Step part 111: Upper part 112: Wall part 114: Convex part 116: Tip part 118: Bottom part 120: Preventive member arrangement part 122: Pressurized Member 124: Sliding member 126: Recess 128: Preventing member 130: Recording medium

Claims (6)

With a rotating body,
An endless band that contacts the rotating body and forms a contact area;
A heating source for heating the contact area;
A holder rotatably holding the endless strip inside the endless strip;
And a sliding member provided between the endless band and the holding body for sliding movement of the endless band.
A convex portion is formed on one of the holding body and the sliding member, and a concave portion is formed on the other,
The convex portion and the concave portion are fitted to each other, and the sliding member is fixed to the holder.
A prevention member disposed on the holder so as to contact the distal end side of the convex portion in the rotational direction of the endless strip, which prevents the convex portion from being disengaged from the concave portion A fixing device having a member. The preventing member is impregnated with a lubricant,
The fixing device according to claim 1, wherein an inner surface side of the endless belt-shaped body is in contact with the preventing member. The inside of the endless band is provided to be in contact with the preventing member, and the moving direction of the endless band at the position where the inside of the endless band is in contact with the preventing member is the convex portion The fixing device according to claim 1, wherein the fixing device is provided so as to have a component in a direction in contact with the surface.   A second height in which the first height of the prevention member in the radial direction of the endless band, the portion of the holding body adjacent to the prevention member where the convex portion is formed, and the thickness of the sliding member The fixing device according to any one of claims 1 to 3, wherein the first height of the preventing member is higher when the heights of the two are compared.   The endless belt according to any one of claims 1 to 4, wherein the endless strip is separated from a portion in which the convex portion of the holder adjacent to the preventing member is formed and a thickness of the sliding member. Fixing device as described. An image forming apparatus comprising the fixing device according to any one of claims 1 to 5.

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