JP4210941B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus provided with a paper discharge roller for discharging a recording paper on which a toner image is fixed to the outside.

An image forming apparatus such as a copier, a facsimile machine, or a printer has a photosensitive drum that transfers a toner image onto a recording sheet, a fixing roller that fixes a toner image transferred from the photosensitive drum onto a recording sheet, and the toner image is fixed. A paper discharge roller that discharges the recording paper to a paper discharge tray, and a paper discharge press roller disposed at a position facing the paper discharge roller. According to this image forming apparatus, the recording paper on which the toner image is transferred onto the recording paper by the photosensitive drum and the toner image is fixed by the fixing roller is disposed on the downstream side of the fixing paper in the recording paper conveyance direction. The paper passes through a transport path (recording paper transport guide) and is discharged to a paper discharge tray by a paper discharge roller and a paper discharge press roller.
JP 2002-87676 A

  By the way, in the conventional image forming apparatus, the recording paper is nipped (niped) by the paper discharge roller and the paper discharge press roller and discharged to the outside. If it does not act, there is a problem that the discharge effect of the recording paper is reduced.

  In view of the above circumstances, an object of the present invention is to provide an image forming apparatus capable of greatly improving the recording paper discharge effect.

The invention of claim 1 includes a rotatably provided a discharge roller rotatably in a position facing the conveying guide member and the sheet discharging a position on the rollers constituting the conveyance path of the recording sheet An image forming apparatus that sandwiches a recording sheet on which a toner image has been fixed between the discharge roller and the press roller, and discharges the recording sheet to the outside. A press roller body member, a rubber member having a diameter larger than the diameter of the press roller body member and applying a frictional force greater than a predetermined value to the recording paper, and provided between the rubber member and the transport guide member A contact preventing member that prevents the rubber member from contacting the transport guide member, and the rubber member is an inner part of the press roller body member when assembled to the press roller body member. An insertion portion that is inserted on the side, and a diameter-enlarged portion that is larger in diameter than the diameter of the press roller main body member, and the contact prevention member is attached to the press roller main body member when the press roller is assembled. A positioning portion that is inserted inside the insertion portion in the radial direction of the main body member, and a pressing portion that presses the enlarged diameter portion against the end surface of the press roller main body member when assembled to the press roller main body member. It is characterized by having.

According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the transport guide member and the contact prevention member are made of resin .

The invention of claim 3 is the image forming apparatus according to claim 2, wherein the contact prevention member is characterized by being composed of polyacetal.

According to a fourth aspect of the present invention, in the image forming apparatus according to any one of the first to third aspects, the press roller body member, the rubber member, and the contact prevention member rotate integrally. It is characterized by.

According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, the recording paper is nipped and conveyed by the paper discharge roller and the press roller, and the paper discharge A cross section of the recording paper in a direction orthogonal to the conveyance direction of the recording paper in the recording paper holding portion held between the roller and the press roller is a wave shape .

According to the present invention, the recording paper on which the toner image is fixed is sandwiched between the paper discharge roller and the press roller and discharged to the outside. Here, since the press roller is provided with a rubber member, when the recording paper is sandwiched between the paper discharge roller and the press roller, a friction force of a predetermined level or more can be applied to the recording paper. Thereby, the discharge effect of the recording paper can be greatly improved.

According to the present invention, the press roller has a cylindrical press roller main body member and a rubber member having a diameter larger than the diameter of the press roller main body member. And the rubber member causes a predetermined or higher frictional force to act on the recording paper. As a result, it is possible to easily apply a friction force of a predetermined level or more to the recording paper with a simple configuration.

According to the present invention, since the contact preventing member is provided between the rubber member and the conveyance guide member, it is possible to prevent the rubber member from contacting the conveyance guide member when the press roller rotates. it can. Thereby, when a press roller rotates, it can prevent that a rubber member rubs against a conveyance guide member and noise is generated.

According to the present invention, since the conveyance guide member and the contact prevention member are made of resin, no loud noise is generated even if they are in contact with each other.

According to this invention, since the contact prevention member is comprised with the polyacetal, a contact prevention member can be shape | molded cheaply and easily with a shaping | molding die.

According to the present invention, the press roller body member, the rubber member, and the contact prevention member rotate together with the members adjacent to each other, so that the backlash between the members is reduced and the wear of each member is reduced. Can be reduced. In addition, since each member rotates integrally, variation in the force for nipping the recording paper during conveyance is reduced, and the conveyance accuracy of the recording paper can be improved.

According to the present invention, the recording sheet cross section in the direction orthogonal to the recording sheet conveyance direction in the recording sheet nipping portion sandwiched between the paper discharge roller and the press roller is corrugated. The recording paper stacked on the paper discharge tray can be prevented from being bent or sinking.

  Next, an image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings.

  As shown in FIGS. 1 and 2, the image forming apparatus 10 includes an image forming apparatus main body 12 serving as a casing. A paper feed cassette 14 is disposed below the image forming apparatus main body 12. A flapper 16 is provided inside the paper feed cassette 14. A predetermined size of recording paper is laminated on the upper portion of the flapper 16. A pickup roller 18 is disposed in the vicinity of the paper feed cassette 14. Further, the flapper 16 is urged upward by a spring member 20 so that the upper surface of the stacked recording paper contacts the pickup roller 18. In this state, when the pickup roller 18 is rotationally driven, the recording paper is fed to the recording paper conveyance path 22 one by one by the frictional force.

  A feed roller 24 and a press roller 26 are disposed downstream of the pickup roller 18 in the recording paper feeding direction. By the feed roller 24 and the press roller 26, the recording paper is conveyed downstream in the recording paper conveyance direction through the recording paper conveyance path 22. A photosensitive drum 28 and a transfer roller 30 are disposed on the downstream side of the feed roller 24 and the press roller 26 in the recording paper conveyance direction. A paper dust removing roller 32 and a corona charger 34 are disposed along the periphery of the photosensitive drum 28. A developing unit 36 is disposed in the vicinity of the photosensitive drum 28. Further, an exposure head 38 is disposed in the vicinity of the developing device 36.

  The paper dust removing roller 32 is composed of a conductive sponge or the like, and removes toner and paper dust adhering to the surface of the photosensitive drum 28 after transfer. The corona charger 34 uniformly charges the surface of the photosensitive drum 28 by discharge from the corotron. An electrostatic latent image is formed by exposing the photosensitive drum 28 uniformly charged by the corona charger 34 according to the image recording signal by the exposure head 38. Then, the toner in the developing device 36 is transferred to the electrostatic latent image formed on the photosensitive drum 28, and the electrostatic latent image is visualized. Further, the transfer roller 30 described above is disposed at a position facing the photosensitive drum 28 with the recording paper interposed therebetween, and the toner formed on the surface of the photosensitive drum 28 when a predetermined voltage is applied to the transfer roller 30. The image is transferred onto the recording paper by the transfer roller 30.

  A fixing roller 40 and a fixing press roller 42 are disposed on the downstream side of the photosensitive drum 28 and the transfer roller 30 in the recording paper conveyance direction. The toner image transferred to the recording paper is fixed by the recording paper being sandwiched between the fixing roller 40 and the fixing press roller 42 and heated and pressed.

  Further, two paper discharge rollers 58 and two paper discharge press rollers (press rollers) 50 are respectively arranged on the downstream side of the fixing roller 40 and the fixing press roller 42 in the recording paper conveyance direction. Specifically, the two paper discharge rollers 58 are disposed so as to be rotatable by the lower conveyance guide 48 positioned on the lower side, and the two paper discharge press rollers 50 are positioned on the upper side. A conveyance guide (conveyance guide member) 46 is disposed so as to be rotatable. Each paper discharge press roller 50 is provided at a position facing each paper discharge roller 58. A discharge tray 44 is formed in the image forming apparatus main body 12, and the recording sheet conveyed through the recording sheet conveyance path 22 is nipped and discharged by a discharge roller 58 and a discharge press roller 50. It is discharged to the paper tray 44.

  Here, the configuration of the paper discharge press roller 50 will be described in detail. Since each discharge press roller 50 has the same configuration, one discharge press roller 50 will be described below as an example.

  As shown in FIGS. 2 and 3, the paper discharge press roller 50 includes a cylindrical press roller body member 52. The press roller body member 52 is made of a resin such as polyacetal (POM). Further, rubber members 54 made of rubber are attached to both ends of the press roller body member 52. Each rubber member 54 includes an insertion portion 54A that is inserted into the end portion of the press roller body member 52, and a diameter-expanded portion 54B that is integrally formed with the insertion portion 54A and has a diameter larger than the diameter of the press roller body member 52. , Is composed of. Further, each sliding member (contact prevention member) 56 is mounted on the press roller main body member 52 from the diameter-expanded portion 54 </ b> B side of each rubber member 54. Each sliding member 56 is integrally formed with each positioning portion 56A and each positioning portion 56A inserted into the radial direction inside each insertion portion 54A of each rubber member 54 inserted into the press roller body member 52, and each rubber. Each of the enlarged diameter portions 54B of the member 54 is configured by a pressing portion 56B that presses each end surface of the press roller body member 52. Each sliding member 56 is made of a resin such as polyacetal (POM). Thus, the paper discharge press roller 50 includes a press roller body member 52, a pair of rubber members 54 provided so as to sandwich the press roller body member 52, and a pair of rubber members 54 provided so as to sandwich the rubber member 54. The press roller main body member 52, the rubber member 54, and the sliding member 56 are configured to be fitted to adjacent members and rotate integrally.

  Further, as shown in FIG. 2, each of the paper discharge press rollers 50 includes a bearing portion 64 formed on the upper conveyance guide 46 with a rotating shaft 60 formed of a coil spring passing through the paper discharge press roller 50. The rotary shaft 60 is rotatably attached to the upper conveyance guide 46.

  A plurality of (three in this embodiment) rollers 62 that rotate when the recording paper is transported are attached to the upper transport guide 46. Each paper discharge press roller 50 and the plurality of rollers 62 are disposed so as to be positioned substantially in a straight line.

  Further, when the recording paper is nipped and conveyed by the paper discharge roller 58 and the paper discharge press roller 50, the recording is performed in the nipping portion of the recording paper held by the paper discharge roller 58 and the paper discharge press roller 50. The cross section of the recording paper in the direction orthogonal to the paper transport direction is a wave shape.

  Next, the operation of the image forming apparatus 10 of this embodiment will be described.

  As shown in FIGS. 1 and 2, the recording paper on which the toner image is fixed by the fixing roller 40 and the press roller 42 is the recording paper conveyance path 22 positioned downstream of the fixing roller 40 and the press roller 42 in the recording paper conveyance direction. Will be transported. Then, the recording paper is conveyed through the recording paper conveyance path 22 constituted by the lower conveyance guide 48 and the upper conveyance guide 46, and eventually reaches the paper discharge roller 58 and the paper discharge press roller 50. The recording paper is sandwiched between the paper discharge roller 58 and the paper discharge press roller 50, and is discharged to the paper discharge tray 44 by the rotation of the paper discharge roller 58.

  Here, since each discharge press roller 50 is provided with a rubber member 54, when the recording sheet is sandwiched between the discharge roller 58 and the discharge press roller 50, the recording sheet has a predetermined amount or more. A frictional force can be applied. Thereby, the discharge effect of the recording paper can be greatly improved.

  In particular, each discharge press roller 50 includes a cylindrical press roller main body member 52 and a rubber member 54 having a diameter larger than the diameter of the press roller main body member 52, so that the recording paper is discharged. When nipped by the roller 58 and the paper discharge press roller 50, the nip pressure is increased by the rubber member 54, and a predetermined or higher frictional force is applied to the recording paper. As a result, it is possible to easily apply a friction force of a predetermined level or more to the recording paper with a simple configuration.

  In addition, since each sliding member 56 is provided between each rubber member 54 of each paper discharge press roller 50 and the upper conveyance guide 46, each paper discharge press roller 50 rotates each time. It is possible to prevent the rubber member 54 from coming into contact with the upper conveyance guide 46. Thus, it is possible to prevent the rubber members 54 from rubbing against the upper conveyance guide 46 and generating noise when the discharge rollers 50 are rotated.

  In particular, since the upper conveyance guide 46 is made of polycarbonate (PC) and each sliding member 56 is made of a resin such as polyacetal (POM), no loud noise is generated even if they come into contact with each other. Further, when the upper conveyance guide 46 is made of polycarbonate (PC) and each sliding member 56 is made of a resin such as polyacetal (POM), it can be easily and inexpensively formed by a mold.

  Further, by setting the thickness of each sliding member 56 so as to fill the gap between each rubber member 54 of each paper discharge press roller 50 and the bearing portion 64 of the upper conveyance guide 46, each paper discharge press. The roller 50 can be prevented from moving in the axial direction (the direction of arrow A in FIG. 2). As a result, the recording paper discharge effect can be greatly improved.

  Further, since the press roller main body member 52, the rubber member 54, and the sliding member 56 are fitted and rotated integrally with members adjacent to each other, rattling between the members is reduced and wear of each member is reduced. Can be reduced. In addition, since each member rotates integrally, variation in the force for nipping the recording paper during conveyance is reduced, and the conveyance accuracy of the recording paper can be improved.

  Further, since the recording sheet cross section in the direction perpendicular to the recording sheet conveyance direction in the recording sheet nipping portion sandwiched between the sheet discharge roller 58 and the sheet discharge press roller 50 is corrugated, the recording to be conveyed The paper can be stiffened, and the recording paper stacked on the paper discharge tray 44 can be prevented from being bent or sunk.

  In the image forming apparatus 10 of the present embodiment, the configuration in which the sliding members 56 are attached to the paper discharge press rollers 50 disposed in the upper conveyance guide 46 has been described as an example. However, the configuration is limited to this configuration. However, the present invention can be applied to all roller members used in the image forming apparatus 10.

1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a plan view of a conveyance guide member constituting the image forming apparatus according to the embodiment of the present disclosure. 1 is an exploded view of a press roller constituting an image forming apparatus according to an embodiment of the present invention.

Explanation of symbols

10 Image forming apparatus 46 Upper conveyance guide (conveyance guide member)
50 Press roller for paper discharge (press roller)
52 Press roller body member 54 Rubber member 56 Sliding member (contact prevention member)
58 Paper discharge roller

Claims (5)

Yes and rotatably provided a discharge roller, a press roller which is rotatably arranged at a position facing the conveying guide member and the sheet discharging a position on the rollers constituting the conveyance path of the recording sheet, the And an image forming apparatus that sandwiches the recording paper with the toner image fixed between the paper discharge roller and the press roller and discharges the recording paper to the outside.
The press roller includes a cylindrical press roller main body member, a rubber member having a diameter larger than the diameter of the press roller main body member, and exerts a predetermined frictional force on the recording paper, the rubber member, and the conveyance guide A contact preventing member provided between the member and the rubber member for preventing the rubber member from contacting the transport guide member,
The rubber member is inserted into the inner peripheral side of the press roller body member when assembled to the press roller body member, and an enlarged diameter part having a diameter larger than the diameter of the press roller body member, Have
The contact preventing member is assembled to the press roller body member, and a positioning portion that is inserted radially inside the insertion portion that is located radially inside the press roller body member when assembled to the press roller body member. And a pressing portion that presses the enlarged diameter portion against an end surface of the press roller body member.   The image forming apparatus according to claim 1, wherein the conveyance guide member and the contact prevention member are made of resin.   The image forming apparatus according to claim 2, wherein the contact prevention member is made of polyacetal.   The image forming apparatus according to claim 1, wherein the press roller body member, the rubber member, and the contact prevention member rotate integrally. The recording paper is nipped and conveyed by the paper discharge roller and the press roller,
2. The recording paper section in a direction perpendicular to the recording paper conveyance direction in the recording paper clamping portion sandwiched between the paper discharge roller and the press roller is corrugated. 5. The image forming apparatus according to any one of 4 above.

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