JP2010217772A - Fixing structure of support shaft and fixing device using the same, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing structure of a support shaft compactly configured by collectively arrange each positioning part for positioning and fixing the support shaft rotatably supporting a rotary member. <P>SOLUTION: The fixing structure includes: the support shaft 330 for rotatably supporting the rotary member G2 and fixed on a housing 300H; and shaft support parts 300Hf, 300He having through-holes 300Hf<SB>0</SB>, 300He<SB>0</SB>and supporting the support shaft 330 on both axial ends of the support shaft 330. The structure forms a substantially cylindrical radial direction positioning part 330Pr on one axial end of the support shaft 330, and on the radial direction positioning part 330pr, the structure coaxially arranges and forms a circumferential positioning part 330pc projecting in a radial direction and an axial positioning part 330Ps along a circumferentially direction. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fixing structure of a support shaft, a fixing device using the same, and an image forming apparatus.

  In general, in an image forming apparatus such as a copying machine or a printer using an electrophotographic system, a large number of rotating members such as a photosensitive drum, a charging roll, a transfer roll, a transfer belt, and a transport roll and a large number of such rotating members are rotatably supported. Components such as a support shaft are provided. For example, a fixing device that forms a permanent image by heating and pressurizing an unfixed toner image transferred onto a recording medium is provided with components such as a conveyance guide roll that guides conveyance of the recording medium after fixing. Various attachment structures for positioning and fixing these constituent members and attaching them to the apparatus housing are employed (for example, see Patent Document 1).

  Here, in Patent Document 1, a metal fixture formed so as to be detachable with respect to a resin support member is provided, and a thermostat is attached to the metal fixture so as to face the heating roll. A fixing device is disclosed.

JP 2000-356920 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide a support shaft fixing structure in which positioning portions for positioning and fixing a support shaft for rotatably supporting a rotating member can be arranged in a compact manner, and a fixing device using the same. Another object is to provide an image forming apparatus.

  In order to achieve the above object, the support shaft fixing structure according to claim 1 includes a support shaft that is rotatably supported by the rotating member, a support shaft that is fixed to a housing, and a through hole. A shaft support portion that supports the support shaft at both axial end portions of the shaft, and a substantially cylindrical radial positioning portion is formed at one axial end portion of the support shaft. In the direction positioning portion, a circumferential positioning portion and an axial positioning portion protruding in the radial direction are coaxially arranged along the circumferential direction.

  The structure for fixing the support shaft according to claim 2 is the structure according to claim 1, wherein a handle portion is formed on the outer side in the axial direction of the radial positioning portion, and a corresponding shaft support portion has A plate-like elastic piece that is elastically displaceable in the axial direction is formed, and the elastic piece is placed on the circumferential positioning portion when the support shaft is rotated in a predetermined fixing direction. A drive surface that is displaced in the axial direction and an anti-rotation surface that prevents rotation of the support shaft are formed.

  The support shaft fixing structure according to claim 3 is the structure according to claim 2, wherein the shaft support portion has a through-hole having an inner diameter substantially equal to an outer diameter of the radial positioning portion of the support shaft. It is formed and extends in the radial direction along the rotational operation direction of the support shaft so that the circumferential positioning portion and the axial positioning portion can be inserted in the axial direction on both sides of the elastic piece. The notch part to be formed is formed.

  The support shaft fixing structure according to claim 4 is the structure according to claim 3, wherein the axial positioning portion is formed downstream of the circumferential positioning portion in the rotational operation direction. Is.

  The support shaft fixing structure according to claim 5 is the structure according to any one of claims 2 to 4, wherein the drive surface is directed from the front end portion in the rotational operation direction of the circumferential positioning portion toward the rear end portion. The rotation prevention surface is formed as a facing surface facing the side surface of the circumferential positioning portion in parallel with the side surface of the elastic piece. It is characterized by this.

  A support shaft fixing structure according to a sixth aspect is the structure according to any one of the third to fifth aspects, wherein the support shaft fixing structure is formed on the upstream side in the rotational operation direction among the notches formed on both sides of the elastic piece. While the width of the notch is formed to be greater than the width of the circumferential positioning portion, the width of the notch formed downstream of the support shaft in the rotational operation direction is the width of the circumferential positioning portion. It is characterized by being formed substantially the same.

  The support shaft fixing structure according to claim 7 is the structure according to any one of claims 2 to 6, wherein the support shaft is formed with an axial stopper portion integrated with the handle portion. The stopper portion and the axial positioning portion are arranged and formed with an interval in the axial direction by the thickness in the axial direction of the elastic piece.

  The fixing device according to claim 8, wherein a heating member having a heating source therein, a heating member formed to be rotatable, a pressure member in pressure contact with the heating member, and the heating member and the pressure member are provided. A support shaft according to any one of claims 1 to 7, wherein any one of the rotating members constituting the transport guide member includes a transport guide member disposed on the downstream side of the fixing pressure contact portion formed to face the support shaft. It is characterized by being attached to the housing by the fixed structure.

  According to a ninth aspect of the present invention, there is provided an image forming apparatus comprising: an image forming unit that forms an image on a recording medium; and the fixing device according to the eighth aspect.

  According to the first aspect of the present invention, the positioning parts such as the radial positioning part, the circumferential positioning part, and the axial positioning part for positioning and fixing the support shaft are compactly integrated and arranged on a single support shaft. Can be formed.

  According to the second aspect of the present invention, the operability and workability at the time of positioning and fixing the support shaft are improved, the rotation of the circumferential positioning portion is prevented by the rotation operation of the single member, and the elastic piece drive guide. Can be realized easily.

  According to the third aspect of the present invention, it is possible to easily mount the through shaft, the circumferential positioning portion, and the axial positioning portion to the housing that enables the radial positioning and fixing of the support shaft with high accuracy without rattling. The cutout portion and the elastic piece displaced in a predetermined direction can be integrally formed on the same shaft support portion.

  According to invention of Claim 4, the number of installation of a notch part can be set to required minimum.

  According to the fifth aspect of the present invention, different functional surfaces such as a drive surface that smoothly elastically displaces the elastic piece in a predetermined direction and a rotation prevention surface that reliably prevents rotation of the circumferential positioning portion by surface contact are the same. It can be easily formed on the member.

  According to the sixth aspect of the present invention, it is possible to easily insert the support shaft into the cut-out portion, and to perform positioning and fixing in the circumferential direction with high accuracy without rattling.

  According to the seventh aspect of the present invention, the axial positioning and fixing can be realized with high accuracy without rattling.

  According to the eighth aspect of the present invention, the support shaft fixing structure according to the present invention can be suitably applied to a fixing device.

  According to the ninth aspect of the present invention, the support shaft fixing structure according to the present invention can be suitably applied to an image forming apparatus.

1 is a schematic configuration diagram showing an embodiment of an image forming apparatus according to the present invention. FIG. 2 is a schematic perspective view for explaining a configuration of a fixing device according to the present invention. FIG. 2 is a schematic cross-sectional view for explaining an internal configuration of a fixing device according to the present invention. 4A and 4B are schematic views illustrating a configuration of a conveyance guide member of the fixing device according to the present invention, where FIG. 5A is a perspective view, and FIG. It is a figure for demonstrating the fixing structure of the support shaft which concerns on this invention, (a) is a typical enlarged view of a support shaft, (b) is a schematic diagram which shows a shaft support part (housing part). It is a schematic diagram for demonstrating the fixing structure of the support shaft which concerns on this invention, (a) is a side view which penetrated the support shaft in the housing part, (b) is positioning fixed by rotating a support shaft. It is a side view which shows the state which carried out. It is a schematic diagram for demonstrating the fixing operation of the support shaft which concerns on this invention, and is a perspective view which shows the state before inserting a support shaft in a housing part. It is a schematic diagram for demonstrating the fixing operation of the support shaft which concerns on this invention, (a) is a perspective view which shows the state which penetrated the support shaft in the housing part, (b) is positioning by rotating a support shaft. It is a perspective view which shows the state fixed. It is a schematic diagram for demonstrating the fixing operation of the support shaft which concerns on this invention, and is a top view which shows the state which penetrated the support shaft to the housing part.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, a schematic configuration of an image forming apparatus to which the present invention can be applied will be described with reference to FIG. Here, FIG. 1 is a configuration diagram showing a tandem type digital color copying machine as an example of an image forming apparatus to which the present invention is applicable.

  In FIG. 1, reference numeral 1 denotes a main body of a tandem type digital color copying machine as an example of an image forming apparatus to which the present invention can be applied. In a state where originals 2 are separated one by one at the upper part of the main body 1. An automatic document conveying device 3 that automatically conveys and a document reading device 4 that reads an image of the document 2 conveyed by the automatic document conveying device 3 are provided. The document reader 4 illuminates a document 2 placed on a platen glass 5 with a light source 6, and reflects a reflected light image from the document 2 from a full-rate mirror 7, half-rate mirrors 8 and 9, and an imaging lens 10. The image reading element 11 made of a CCD or the like is scanned and exposed through a reduction optical system, and the image material 11 reflects the color material reflected light image of the original 2 by a predetermined dot density (for example, 16 dots / mm). ).

  The color material reflected light image of the document 2 read by the document reading device 4 is subjected to image processing, for example, as document reflectance data of three colors of red (R), green (G), and blue (B) (8 bits each). The image processing apparatus 12 sends images such as shading correction, position shift correction, brightness / color space conversion, gamma correction, frame deletion, color / moving editing, etc. to the reflectance data of the document 2. Processing is performed. In addition, the image processing device 12 performs predetermined image processing on image data sent from a personal computer or the like.

  The image data that has been subjected to the predetermined image processing by the image processing device 12 as described above is processed by the image processing device 12 in the same manner as yellow (Y), magenta (M), cyan (C), and black (K). (8 bits each) is converted into four-color original reproduction color material gradation data, and as described below, image formation of each color of yellow (Y), magenta (M), cyan (C), and black (K) The images are sent to the exposure devices 14 of the units 13Y, 13M, 13C, and 13K, and the exposure device 14 performs image exposure with the laser beam LB in accordance with the original reproduction color material gradation data of each color.

  Inside the tandem digital color copying machine main body 1, four image forming units 13Y, 13M, 13C, and 13K of yellow (Y), magenta (M), cyan (C), and black (K) are horizontally arranged. They are arranged in parallel at regular intervals in the direction.

  These four image forming units 13Y, 13M, 13C, and 13K are all configured in the same manner, and are roughly divided into a photosensitive drum 15 as an image carrier that is rotationally driven at a predetermined speed, and the photosensitive drum. A charging roll 16 for primary charging that uniformly charges the surface of 15, and an exposure device 14 including a scanning optical system that exposes an image corresponding to each color on the surface of the photosensitive drum 15 to form an electrostatic latent image, and The developing unit 17 develops the electrostatic latent image formed on the photosensitive drum 15 with each color toner (developer), and the drum cleaning unit 18 cleans the surface of the photosensitive drum 15.

  The exposure device 14 is configured in common to the four image forming units 13Y, 13M, 13C, and 13K, and modulates four semiconductor lasers (not shown) in accordance with the original reproduction color material gradation data of each color, Laser light beams LB-Y, LB-M, LB-C, and LB-K are emitted from these semiconductor lasers according to gradation data. Of course, the exposure apparatus 14 may be individually configured for each of a plurality of image forming units. The laser beams LB-Y, LB-M, LB-C, and LB-K emitted from the semiconductor laser are applied to the rotary polygon mirror 19 through an unillustrated f-θ lens. A deflection scan is performed. Laser beams LB-Y, LB-M, LB-C, and LB-K deflected and scanned by the rotary polygon mirror 19 are scanned obliquely from below on the photosensitive drum 15 through a plurality of reflection mirrors (not shown). Exposed.

  The exposure apparatus 14 is hermetically sealed by a rectangular parallelepiped frame 20, and four laser beams LB-Y, LB-M, LB-C, and LB-K are applied to the upper portion of the frame 20. In order to expose the photosensitive drums 15Y, 15M, 15C, and 15K of the image forming units 13Y, 13M, 13C, and 13K, transparent glass windows 21Y, 21M, 21C, and 21K are provided as shield members. . These glass windows 21Y, 21M, 21C, and 21K are members located at the uppermost position on the optical path along the laser beam LB of the exposure apparatus 14.

  From the image processing apparatus 12, an exposure apparatus 14 provided in common for the image forming units 13Y, 13M, 13C, and 13K for each color of yellow (Y), magenta (M), cyan (C), and black (K). In addition, the image data of each color is sequentially output, and the laser beams LB-Y, LB-M, LB-C, and LB-K emitted according to the image data from the exposure device 14 correspond to the corresponding photosensitive drums 15Y and 15M. , 15C and 15K are scanned and exposed to form an electrostatic latent image. The electrostatic latent images formed on the photosensitive drums 15Y, 15M, 15C, and 15K are respectively yellow (Y), magenta (M), cyan (C), and black (by the developing devices 17Y, 17M, 17C, and 17K. K) is developed as a toner image (developer image) of each color.

  Each color of yellow (Y), magenta (M), cyan (C), and black (K) sequentially formed on the photosensitive drums 15Y, 15M, 15C, and 15K of the image forming units 13Y, 13M, 13C, and 13K. The toner images are transferred in multiple by the primary transfer rolls 26Y, 26M, 26C, and 26K onto the intermediate transfer belt 25 disposed over the image forming units 13Y, 13M, 13C, and 13K. The intermediate transfer belt 25 is wound around the drive roll 27 and the backup roll 28 with a constant tension, and is driven to rotate by a dedicated drive motor (not shown) having excellent constant speed. Thus, the circulation drive is performed at a predetermined speed in the direction of the arrow. As the intermediate transfer belt 25, for example, a flexible synthetic resin film such as PET is formed in a band shape, and both ends of the synthetic resin film formed in a band shape are connected by means such as welding, thereby endless A belt-shaped one is used.

  The yellow (Y), magenta (M), cyan (C), and black (K) toner images transferred onto the intermediate transfer belt 25 in a multiple manner are transferred to the backup roll 28 by a secondary transfer roll 29. The recording paper P, which is secondarily transferred onto the recording paper P by the pressure contact force and electrostatic force, and onto which the toner images of these colors are transferred, is conveyed to the fixing device 30 positioned above. The secondary transfer roll 29 is in pressure contact with the side of the backup roll 28, and secondary-transfers each color toner image onto the recording paper P conveyed from below to above. The recording paper P on which the toner images of the respective colors are transferred is subjected to a fixing process with heat and pressure by the fixing device 30 and then discharged onto a discharge tray 33 provided on the upper portion of the main body 1 by a discharge roll 32. The

  The recording paper P having a predetermined size from the paper feed cassette 34 is once transported to a registration roll 38 via a paper transport path 37 by a paper feed roller 35 and a pair of rollers 36 for paper separation and transport. Stopped. The recording paper P supplied from the paper feed cassette 34 is sent to the secondary transfer position of the intermediate transfer belt 25 by a registration roll 38 that rotates at a predetermined timing.

  In the digital color copying machine, when full-color double-sided copying is performed, the recording paper P having an image fixed on one side is not directly discharged onto the discharge tray 33 by the discharge roll 32 but is not shown. The conveyance direction is switched by the switching gate, and the sheet is conveyed to the duplex conveyance unit 40 via the sheet conveyance roller pair 39. In the double-sided conveyance unit 40, the recording paper P is conveyed to the registration roll 38 again with the pair of conveyance rollers (not shown) provided along the conveyance path 41 being reversed. This time, after the image is transferred and fixed on the back surface of the recording paper P, it is discharged onto the discharge tray 33.

  The four image forming units 13Y, 13M, 13C, and 13K of yellow, magenta, cyan, and black are all configured in the same manner. In these four image forming units 13Y, 13M, 13C, and 13K, As described above, yellow, magenta, cyan, and black toner images are sequentially formed at predetermined timings. As described above, the image forming units 13Y, 13M, 13C, and 13K for the respective colors include the photosensitive drums 15, and the surfaces of these photosensitive drums 15 are uniformly charged by the charging roll 16 for primary charging. The Thereafter, the surface of the photosensitive drum 15 is scanned and exposed to an image forming laser beam LB emitted from the exposure device 14 according to the image data, and an electrostatic latent image corresponding to each color is formed. The laser beam LB scanned and exposed on the photosensitive drum 15 is set so as to be exposed at a predetermined inclination angle from an obliquely lower side slightly to the right side from directly below the photosensitive drum 15. The electrostatic latent image formed on the photosensitive drum 15 is made up of yellow, magenta, cyan, and black toners by the developing rolls of the developing devices 17 of the image forming units 13Y, 13M, 13C, and 13K. The toner images are developed into visible toner images, and these visible toner images are sequentially transferred in multiple onto the intermediate transfer belt 25 by the charging of the primary transfer roll 26.

  Residual toner, paper dust, and the like are removed from the surface of the photosensitive drum 15 after the toner image transfer process by the drum cleaning device 18 to prepare for the next image forming process. The drum cleaning device 18 includes a cleaning blade (not shown), and the cleaning blade removes residual toner, paper dust, and the like on the photosensitive drum 15. Further, residual toner, paper dust, and the like are removed from the surface of the intermediate transfer belt 25 after the toner image transfer process is completed by the belt cleaning device 43 to prepare for the next image forming process. The belt cleaning device 43 includes a cleaning brush 43a and a cleaning blade 43b. The cleaning brush 43a and the blade 42 remove residual toner, paper dust, and the like on the intermediate transfer belt 25.

  In the present embodiment, above the intermediate transfer belt 25, yellow (Y), magenta (M), cyan (C), and black (K) developing devices 17 having predetermined colors are provided. Toner cartridges 50Y, 50M, 50C, and 50K for supplying developer (mainly toner or toner containing carrier) are disposed.

  Next, the configuration of the fixing device 30 according to the present embodiment will be described with reference to FIGS. Here, FIG. 2 is a schematic perspective view showing an external configuration of the fixing device according to the present embodiment, and FIG. 3 is a schematic sectional view showing an internal configuration of the fixing device according to the present embodiment. .

  As shown in FIGS. 2 and 3, the fixing device 30 according to the present embodiment includes a hollow unit casing 300, and the unit casing 300 is rotated by being connected to a driving source (not shown). A heating roll 301 that is freely formed, and a fixing belt 303 that is rotatably contacted with the heating roll 301 at a predetermined pressure and is driven by the rotation of the heating roll 301 are disposed. Further, a toner image is fixed on the downstream side (in this example, the upper side in FIG. 2, for example) of the pressure contact part (fixing nip part) N of the pair of fixing rotators (in this example, the heating roll 301 and the fixing belt 303). A pair of conveyance guide members (conveyance guide members) 320 for guiding the conveyance of the recording sheet P is disposed so as to be exposed to the outside of the unit housing 300, and the recording after the fixing that has passed through the fixing nip portion N is performed. The paper P is guided by the pair of transport guide members 320 and is transported along a predetermined transport path. Further, a switching lever 310 for changing (switching) the pressure contact force of the fixing nip portion N is disposed on one end side of the unit casing 300 in the axial direction.

  A heating roll 301 as a heating member has an elastic layer such as silicone rubber formed on the surface of a cylindrical core made of metal such as aluminum having excellent mechanical strength and good thermal conductivity. A release layer made of a fluororesin layer such as a PFA tube provided to prevent an unfixed toner image on the recording paper P from being offset is formed on the surface. Further, for example, a halogen lamp 301H as a heating source is provided inside the core, and the recording paper P on which the unfixed toner image is formed is heated by heating the heating roll 301 so that the surface temperature becomes a predetermined temperature. It is supposed to be. In the present embodiment, a temperature sensor S (not shown) that detects the surface temperature of the heating roll 301 in the sheet passing area of the recording paper P is disposed on one side surface of the heating roll 301, and heating is performed by this temperature sensor. The temperature control of the heating source 301H is performed so that the surface temperature of the roll 301 becomes a predetermined temperature.

  On the other hand, the fixing belt 303 as the pressure member may have a single layer structure, but in the present embodiment, a belt having a laminated structure in which a release layer is provided on the surface of the substrate is used. As a base material of the fixing belt 303, if it has heat resistance, for example, a resin base material such as thermosetting polyimide, thermoplastic polyimide, polyamide, polyamideimide, or a metal base material such as stainless steel, nickel, copper alloy, or the like. Used. Further, the release layer preferably has good releasability of the toner adhering to the surface, and examples of the material include PTFE (polytetrafluoroethylene) and PFA (tetrafluoroethylene-perfluoroalkoxyethylene copolymer). ) And FEP (tetrafluoroethylene-hexafluoropropylene copolymer).

  In the present embodiment, a substantially rectangular parallelepiped-shaped pressing member 305 that presses the fixing belt 303 on the surface facing the heating roll 301 and forms a predetermined fixing nip portion N is formed in the fixing belt 303 in the axial direction. A belt traveling guide 307 having a substantially arc-shaped cross section made of, for example, a resin having low thermal conductivity and high rigidity is disposed so as to extend in the axial direction. Then, the pressure contact force (fixing nip load) of the fixing belt 303 to the heating roll 301 is switched via the pressing member 305 by rotating the switching lever 310.

  In addition, the pair of conveyance guide members 320 in the present embodiment has a unit structure and is disposed opposite to the downstream side of the fixing nip portion N. The fixing belt 303 side (in this example, for example, in FIG. The pressure-side conveyance guide member 320L disposed on the upper side of the belt 303 and the heating-side conveyance guide member 320R disposed on the heating roll 301 side (in this example, for example, on the upper side of the heating roll 301 in the figure). Has been. Furthermore, each conveyance guide member 320L, 320R has a plurality of conveyance rolls 320La, 320Ra that are opposed to each other and form a conveyance pressure contact portion (conveyance nip portion) N1 by the conveyance roll pair 320La, 320Ra. is doing.

  Then, the recording paper P on which the unfixed image is formed is heated and pressurized while being inserted into the fixing nip portion N to fix the image, and then the recording paper P that has passed through the nip portion N is conveyed by the conveyance guide member 320. It is conveyed toward the discharge tray 33 and the like.

  Next, a support shaft fixing structure according to the present embodiment will be described with reference to FIGS. In the following embodiments, the structure applied to the rotation shaft 320Ls of the pressure-side conveyance guide member 320L of the fixing device 30 will be described as an example of the support shaft fixing structure according to the present invention. Here, FIG. 4 is a schematic diagram showing a configuration of a conveyance guide member (in this example, a pressure-side conveyance guide member) 320L according to the present embodiment, and FIG. 5A is according to the present embodiment. FIG. 5B is a schematic enlarged view showing the configuration of the support shaft, and FIG. 5B is a schematic view showing the configuration of the shaft support portion (housing portion). FIG. 6A is a schematic side view showing a state where the support shaft is inserted into the housing portion, and FIG. 6B is a schematic side view showing a state where the support shaft is rotated and positioned and fixed. It is. For the sake of simplicity, hereinafter, the pressure-side conveyance guide member 320L will be referred to as a conveyance guide member 320.

  As schematically shown in FIGS. 4A and 4B, a rotation shaft 320s is attached to the conveyance guide member 320 according to the present embodiment, and is arranged at a symmetrical position around the center of the sheet width (this book). In the example, there are four locations), and a plurality of transport rolls 320a formed of an elastic member such as rubber, and the leading ends thereof protrude so as to be orthogonal to the rotating shaft 320s on the upstream side and the downstream side across the rotating shaft 320s, A plurality of guide ribs 320g are provided along the axial direction. In addition, bearing members 320b are disposed at both axial ends of the rotating shaft 320s. The rotation shaft 320s is rotatably attached to the conveyance guide member 320 by the bearing member 320b. One end portion in the axial direction of the rotation shaft 320s (in this example, the left end portion in FIG. 4) extends further in the axial direction beyond the bearing member 320b, and the gear G1 is connected to the rotation shaft 320s at the end portion. It is attached integrally. The gear G1 is arranged so as to mesh with the adjacent gear G2, and the adjacent gear G2 is rotatably supported by the support shaft 330 according to the present embodiment arranged in parallel with the rotation shaft 320s. Yes. The gears G1 and G2, the support shaft 330, and the like are housed in a housing portion 300H having a substantially U-shaped cross section that is provided in the axial direction as a part of the transport guide member 320.

  The transport guide member 320 is connected to a drive source (not shown) via a plurality of gears G1, G2 and the like by the support shaft fixing structure according to the present embodiment as described below, and the rotation shaft 320s is connected to the rotation shaft 320s. It is designed to rotate.

  In the support shaft fixing structure according to the present embodiment, the support shaft 330 has a plate-like handle portion 330a at one end in the axial direction, as shown in an enlarged view in FIG. 5A, and this handle portion 330a. A substantially cylindrical radial positioning portion 330Pr is formed on the inner side in the axial direction. Further, a shaft portion 330s having a smaller diameter is formed on the inner side in the axial direction of the radial direction positioning portion 330Pr. The shaft portion 330s rotatably supports a gear G2 as a rotating member, and a small diameter shaft. The movement of the gear G2 in the axial direction is restricted by a step formed between the portion 330s and the radial positioning portion 330Pr. Further, both end portions in the axial direction of the support shaft 330 are supported by plate-like shaft support portions 300Hf and 300He provided in the housing portion 300H as shown in FIG. 5B, and the support shaft 330 is described later. By rotating the handle portion 330a in a predetermined fixing operation direction (in this example, the counterclockwise direction in FIG. 6), the support shaft 330 can be moved in any of the radial direction, the axial direction, and the circumferential direction. The positioning is fixed.

  As best shown in FIGS. 6A and 6B, the radial positioning portion 330Pr further protrudes in the radial direction along the handle portion 330a (in parallel with the handle portion 330a) on the outer peripheral portion thereof. The substantially square circumferential positioning portion 330Pc provided is formed so as to extend in the axial direction, and downstream of the circumferential positioning portion 330Pc (in this example, the left side of the circumferential positioning portion 330Pc in FIG. 6). ) Is formed with a protruding axial positioning portion 330Ps protruding in the radial direction. The rotational center of the circumferential positioning portion 330Pc and the axial positioning portion 330Ps is coaxially arranged along the circumferential direction of the radial positioning portion 330Pr (support shaft 330).

  The axially outer end of the circumferential positioning portion 330Pc (the end corresponding to the axial position of the snap portion 300Hsp described later) has an axial thickness from the front end to the rear end in the rotational operation direction. An increasing slope (a slope where the length in the width direction perpendicular to the axial direction and the radial direction decreases as it goes outward in the axial direction) is formed as the drive surface 330Pcd (see FIG. 5A). ). On the other hand, on the side surface of the circumferential positioning portion 330Pc (specifically, on the upstream side in the rotational direction parallel to the plane including the axial direction and the radial direction), a shaft support portion (positioning fixing plate) whose details will be described later. A facing surface that is parallel to the side surface (side surface orthogonal to the width direction) of the 300Hf slit 300Hs and the snap portion 300Hsp is formed as a rotation preventing surface 330Pcs. In the present embodiment, as described later, when the rotation prevention surface 330Pcs faces the side surface of the snap portion 300Hsp and is positioned in the circumferential direction (rotation prevention), the downstream side of the drive surface 330Pcd The end is set to face the side surface of the slit 300Hs. That is, the drive surface 330Pcd according to the present embodiment also functions as a circumferential rotation prevention surface.

In the present embodiment, one end of the handle 330a (in this example, the lower end opposite to the circumferential positioning portion 330Pc) extends radially beyond the outer peripheral portion of the cylindrical radial positioning portion 330Pr. projects, by the projecting portion, the stopper portion 330Ps ₀ in the axial direction is formed. Then, the axial distance between the stopper portion 330Ps ₀ and the axial positioning part 330Ps is set to be equivalent to the length and the axial thickness of the positioning and fixing plate 300Hf described below (length).

  On the other hand, as shown in FIG. 5B, shaft support portions 300Hf and 300He for supporting both axial ends of the support shaft 330 are formed in the housing portion 300H.

  Specifically, as shown in FIG. 4, the rotary shaft 320 s is attached to one axial end portion (in this example, the end portion to which the gear G <b> 1 is attached) of the rotary shaft 320 s to which the transport roll 320 a is attached. A substantially downward U-shaped housing portion 300H is formed so as to accommodate (cover) the end portion, the support shaft 330, and the like. And the side plate (side plate which protrudes so as to be orthogonal to the axial direction of the support shaft 330) of the housing part 300H is formed as the shaft support parts 300Hf and 300He.

  More specifically, as best shown in FIG. 5B and the like, a rear end side shaft support portion that supports the rear end portion of the support shaft 330 is provided at a position corresponding to the rear end portion of the support shaft 330. The shaft support plate 300He is formed so as to be orthogonal to the axial direction, and at the position corresponding to the tip portion of the support shaft 330, positioning as a tip side shaft support portion that enables positioning and fixing of the support shaft 330 is possible. The fixed plate 300Hf is formed so as to be orthogonal to the axial direction.

Here, the shaft support plate 300He is formed with a through hole 300He ₀ whose inner diameter is substantially equal to the outer diameter of the shaft portion 330s so that the shaft portion 330s of the support shaft 330 can be inserted.

On the other hand, a through hole 300Hf ₀ into which the substantially cylindrical radial positioning portion 330Pr of the support shaft 330 can be inserted is formed in the positioning fixing plate 300Hf that is the shaft support portion according to the present embodiment. The through hole 300Hf _0, the inner diameter is formed substantially equal to the outer diameter of the radial positioning unit 330Pr, the rear end side of the shaft support plate 300He through holes 300He ₀ and the radial positioning unit 330Pr I coupled with The backlash of the support shaft 330 when the is inserted is reduced, and positioning and fixing in the radial direction can be accurately performed.

Further, the through hole 300Hf ₀ of the positioning fixing plate 300Hf, FIG. 6 (a), the manner best shown (b), a coaxial circumferentially projecting from an outer peripheral portion in the radial direction positioning portion 330Pr radially to correspond to the arranged circumferential positioning portion 330Pc and axial positioning portion 330Ps (in the corresponding circumferential positions), the first slit extending in a radial direction of the through hole 300Hf ₀ (first notch portion) 300Hs ₁ and a second slit (second notch) 300Hs ₂ are formed. In addition, these first slits 300HS ₁ and second slits 300HS _2, the upper are bent so as to extend in the horizontal direction, is sandwiched by these first slits 300HS ₁ and second slits 300HS ₂ Thus, the tip protrudes in a triangular shape toward the center of the support shaft 330, and a snap portion 300Hsp is formed as a plate-like elastic piece that can be displaced in the axial direction.

That is, in this embodiment, the attachment to the housing portion 300H of the through hole 300Hf ₀ and circumferential positioning portion 330Pc and axial positioning part 330Ps to enable accurate positioning and fixing in the radial direction by the radial positioning unit 330Pr easily function unit for positioning and fixing such first slit 300HS ₁ and second slits 300HS ₂ and snap portion 300Hsp displaced in the predetermined axis direction to allow the positioning fixing plate of the same (single) (tip side shaft supporting Part) It is integrally formed in 300Hf, and it is possible to reduce the size and cost associated with the reduction in the number of parts.

  Further, by providing the axial positioning part 330Ps on the downstream side of the circumferential positioning part 330Pc along the rotational operation direction, the number of slits (notches) 300Hs to be installed is minimized as compared with the configuration provided on the upstream side. (In this example, two places) can be set, which can contribute to improvement in the rigidity and positioning stability of the positioning fixing plate 300Hf.

Furthermore, in the present embodiment, the width of the first slit 300Hs ₁ (the length in the direction perpendicular to the radial direction and the axial direction) may be slightly larger than the width of the corresponding circumferential positioning portion 330Pc, the second width of the slit 300HS _2, it is preferable to set to be equal to the width of the circumferential positioning part 330Pc. Thus, during stationary operation of the support shaft 330 to be described later, the second anti-rotation surfaces of the slit 300HS ₂ the circumferential direction positioning portion 330Pc 330pcs and drive surface 330Pcd (specifically, the downstream end portion of the drive surface 330Pcd) It is possible to realize the positioning in the circumferential direction with high accuracy without rattling.

  A method of fixing the support shaft 330 in the support shaft fixing structure according to the present embodiment configured as described above will be described below with reference to FIGS. Here, FIG. 7 is a schematic perspective view showing a state before the support shaft is inserted into the housing portion, and FIG. 8A is a schematic perspective view showing a state where the support shaft is inserted into the housing portion. FIG. 8B is a schematic perspective view showing a state in which the support shaft is rotated and positioned and fixed. FIG. 9 is a schematic plan view showing a state where the support shaft is inserted into the housing portion.

First, as shown schematically in Figure 7, the support shaft 330 in a state in which separated from the housing portion 300H, the through hole 300Hf ₀ of the positioning fixing plate 300Hf, through holes 300He ₀ of shaft support plates 300He via gears G2 Pass through toward. At this time, the support shaft 330 is placed in the through hole 300Hf ₀ so that the circumferential positioning portion 330Pc corresponds to the first slit 300Hs ₁ of the positioning fixing plate 300Hf and the axial positioning portion 330Ps corresponds to the second slit 300Hs _2. Insert.

Then, as schematically shown in FIG. 8 (a), the stopper portion 330Ps ₀ provided at handle 330a of the support shaft 330, pushes the support shaft 330 until it hits the surface of the positioning fixing plate 300Hf. At this time, the support shaft 330 is inserted into the through hole 300Hf ₀ and the radial positioning portion 330Pr formed in a cylindrical shape is fitted to the through hole 300Hf ₀ of the positioning fixing plate 300Hf so that the support shaft 330 is radially aligned. It will be positioned and fixed to.

Next, from this state, as schematically shown in FIG. 8B, the handle portion 330a of the support shaft 330 is rotated counterclockwise (see FIGS. 6A and 6B). At this time, as best shown in FIG. 9, the drive surface 330Pcd of the circumferential positioning portion 330Pc corresponds to the snap portion 300Hsp of the positioning fixing plate 300Hf along the slope formed on the drive surface 330Pcd by the dotted line A. To be displaced in the axial direction. That is, the circumferential positioning part 330Pc rotates in a predetermined operation direction while elastically displacing the snap part 300Hsp. Thereafter, the circumferential positioning part 330Pc is at the time of the move to the second slit 300Hs within ₂ rides over the snap portion 300Hsp, snap portion 300Hsp returns to the original state. Thereby, the side surface (specifically, the side surface parallel to the plane including the radial direction and the axial direction) of the snap portion 300Hsp (second slit 300Hs ₂ ), the rotation prevention surface 330Pcs, and the drive surface 330pcd face each other, and the circumferential direction positioning portion 330Pc is sandwiched in the second slit 300Hs in ₂ (fitted into it), the support shaft 330 is positioned and fixed in the circumferential direction.

  Further, since the snap portion 300Hsp is elastically displaced in a direction orthogonal to the rotational operation direction (in this example, the axial direction), compared to a configuration in which the snap portion is driven in the same direction as the operation direction (for example, the shaft insertion direction), It is possible to reduce the backlash in the axial direction at the time of positioning, and to set a small stroke (operation amount) for obtaining a necessary elastic displacement amount.

Incidentally, the circumferential positioning part 330Pc in a state fitted to the second slit 300Hs _2, the axial positioning part 330Ps, has moved to the rear surface of the positioning fixing plate 300Hf, and the axial positioning part 330Ps, axial By sandwiching the positioning fixing plate 300Hf with the stopper portion 330Ps ₀ whose installation interval is set equal to the thickness of the positioning fixing plate 300Hf, the positioning fixing in the axial direction is performed simultaneously with the positioning fixing in the circumferential direction of the support shaft 330. . That is, in this state, the support shaft 330 is positioned and fixed in any of the radial direction, the circumferential direction, and the axial direction.

  As described above, according to the support shaft fixing structure according to the present embodiment, the radial positioning portion 330pr, the circumferential positioning portion 330Pc and the shaft provided on the same member (the support shaft 330 in this example). The direction positioning part 330Ps can reduce the number of parts of the positioning member without using an E-ring and the like, thereby contributing to downsizing and cost reduction, and the diameter of the support shaft 330 by a simple fixing operation (rotating operation). Positioning and fixing in the direction, circumferential direction, and axial direction can be easily realized.

Further, the shaft structure can be simplified and the degree of freedom of selection of the material constituting the support shaft 330 can be increased as compared with the configuration in which the positioning shaft is provided on the support shaft 330. Specifically, the bending rigidity (flexural modulus) is high, and conventionally, it has been difficult to apply as a snap portion, for example, PPS (thermal deformation temperature: 1.82 N / mm ² 260 ° or more, flame retardancy: It is possible to form the support shaft 330 with a material having excellent heat resistance and flame retardancy (UL94V-0, bending elastic modulus: 13.3 GPa) and a high rigidity. It is possible to easily cope with the high temperature of the usage environment.

  The technical scope of the present invention is not limited to the above-described embodiments, and various modifications or improvements can be added without departing from the scope of the present invention described in the claims. is there. For example, in the above-described embodiment, the inclined surface as the driving surface 330Pcd is formed in the circumferential positioning portion 330Pc, but a similar inclined surface may be formed in the snap portion 300Hsp of the positioning fixing plate 300Hf. In the above-described embodiment, the structure in which the support shaft fixing structure according to the present invention is applied to a part of the support shaft of the conveyance guide member 320 is exemplified. However, naturally, the support guide shaft has a support shaft that supports the rotating member. The supporting shaft fixing structure according to the present invention may be applied to other components (for example, a charging device, a developing device, a transfer device, etc.).

1: Image forming apparatus, 13Y, 13M, 13C, 13K: Image forming unit, 14: Exposure apparatus, 15Y, 15M, 15C, 15K: Photosensitive drum, 16Y, 16M, 16C, 16K: Charging roll, 17Y, 17M, 17C , 17K: Development device, 18Y, 18M, 18C, 18K: Drum cleaning device, 25: Intermediate transfer belt, 26Y, 26M, 26C, 26K: Primary transfer roll, 28: Backup roll, 29: Secondary transfer roll, 30: Fixing device, 33: discharge tray, 34: paper feed cassette, 38: registration roll, 40: duplex transport unit, 43: belt cleaning device, 50Y, 50M, 50C, 50K: toner cartridge, 300H: housing portion, 300He: shaft support plate, 300He _0: through hole, 300Hf: positioning and fixing plate 300Hf _0: through hole, 300HS _1: first slit, 300HS _2: second slit, 300Hsp: snap unit, 301: heating roller, 303: fixing belt, 305: pressing member, 310: switching lever, 320: conveying guide member 320a: conveying roll, 320b: bearing member, 320g: guide rib, 320s: rotating shaft, 330: support shaft, 330Pc: circumferential positioning portion, 330Pcd: driving surface, 330Pcs: anti-rotation surface, 330Pr: radial positioning portion, 330Ps: axial positioning portion, 330Ps _0: stopper portion, 330a: handle portion, 330s: shank, G1, G2: gear, P: recording paper

Claims (9)

A support shaft that rotatably supports the rotating member and is fixed to the housing;
A shaft support portion having a through hole and supporting the support shaft at both axial ends of the support shaft;
A substantially cylindrical radial positioning portion is formed at one axial end portion of the support shaft. Further, the radial positioning portion includes a circumferential positioning portion and an axial positioning portion protruding in the radial direction. A support shaft fixing structure, wherein the support shaft is coaxially arranged along the circumferential direction.   A grip portion is formed on the outer side in the axial direction of the radial positioning portion, and a plate-like elastic piece that can be elastically displaced in the axial direction is formed on the corresponding shaft support portion, and The circumferential positioning portion includes a drive surface that displaces the elastic piece in the axial direction when the support shaft is rotated in a predetermined fixing direction, and an anti-rotation surface that prevents the support shaft from rotating. The support shaft fixing structure according to claim 1, wherein the support shaft fixing structure is formed.   A through hole having an inner diameter substantially equal to the outer diameter of the radial positioning portion of the support shaft is formed in the shaft support portion, and both sides of the elastic piece are arranged along the rotation operation direction of the support shaft. The support shaft according to claim 2, wherein a notch portion extending in a radial direction is formed so that the circumferential positioning portion and the axial positioning portion can be inserted in the axial direction. Fixed structure.   The support shaft fixing structure according to claim 3, wherein the axial positioning portion is formed downstream of the circumferential positioning portion in the rotational operation direction.   The drive surface is formed as a slope whose axial thickness increases from the front end portion to the rear end portion in the rotational operation direction of the circumferential positioning portion, and the rotation prevention surface is the circumferential direction. The support shaft fixing structure according to claim 2, wherein the support shaft fixing structure is formed on the side surface of the positioning portion as an opposing surface that faces the side surface of the elastic piece in parallel.   Of the cutout portions formed on both sides of the elastic piece, the width of the cutout portion formed on the upstream side in the rotational operation direction is greater than the width of the circumferential positioning portion. The support shaft according to any one of claims 3 to 5, wherein a width of the cutout portion formed on the downstream side in the rotational operation direction is formed substantially equal to a width of the circumferential positioning portion. Fixed structure.   The support shaft is formed with an axial stopper portion integrated with the handle portion, and the stopper portion and the axial positioning portion are axially formed by an axial thickness of the elastic piece. The support shaft fixing structure according to any one of claims 2 to 6, wherein the support shaft fixing structure is arranged with a space therebetween. A heating member having a heating source therein and formed rotatably;
A pressure member that presses against the heating member;
A conveyance guide member disposed on the downstream side of the fixing pressure contact portion formed by facing the heating member and the pressure member,
The fixing device according to claim 1, wherein any one of the rotating members constituting the conveyance guide member is attached to the housing by the support shaft fixing structure according to claim 1.   An image forming apparatus comprising: an image forming unit that forms an image on a recording medium; and the fixing device according to claim 8.

Images