JP2014002306A - Fixing device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device in which durability of a fixing belt can be ensured, and an image forming apparatus.SOLUTION: A fixing device includes an endless fixing belt 21, a cylindrical heating member 22 that extends in an axial direction of the fixing belt 21 and is arranged in the radial-direction inside of the fixing belt 21, and flange members 40A that are arranged on both ends of the fixing belt 21. The fixing belt 21 is formed to have the total length longer than the total length of the heating member 22. The flange members 40A are configured to include support parts 41 that are inserted into the inside of both ends of the fixing belt 21 from the outside of the fixing belt 21, and holding parts 42 that protrude from the support parts 41 and inserted into the inside of both ends of the heating member 22. A rotating body 44 is attached to each of the support parts 41 in such a way that the rotating body 44 faces an end surface of the fixing belt 21 and can rotate in a circumferential direction of the fixing belt 21.

Description

  The present invention relates to a fixing device having an endless fixing belt and an image forming apparatus such as a facsimile, a printer, a copying machine, or a complex machine using the electrophotographic method or electrostatic recording method including the fixing device. is there.

  Conventionally, various image forming apparatuses using an electrophotographic system have been developed as image forming apparatuses such as copying machines and printers, and are well-known techniques. In the image forming process, an electrostatic latent image is formed on the surface of a photosensitive drum as an image carrier, and the electrostatic latent image on the photosensitive drum is developed with a toner as a developer to be visualized and developed. This process is established by a process in which a transferred image is transferred onto a recording medium such as transfer paper by a transfer device to carry the image, and a toner image is fixed on the recording medium by a fixing device using pressure or heat.

  In the fixing device, a fixing belt and a pressure roller are arranged so that they contact each other to form a fixing nip. In this fixing device, the above-described toner image is fixed on the recording medium by sandwiching the recording medium in the fixing nip portion and applying heat and pressure to the recording medium.

  As an example of the fixing device, an endless fixing belt, and three roller members (a supporting roller, a fixing auxiliary roller, and a supporting roller, which extend in the axial direction of the fixing belt and support the fixing belt in contact with the inner peripheral surface of the fixing belt) A tension roller), an induction heating unit for heating the fixing belt, and a pressure roller that extends in the axial direction of the fixing roller and presses the fixing belt from the radially outer side toward the fixing auxiliary roller. (For example, refer to Patent Document 1).

  Here, the axial direction of the fixing belt is a direction parallel to the image fixing surface of the recording medium and orthogonal to the moving path of the recording medium.

  In the above-described fixing device, when the pressure roller is pushed toward the auxiliary fixing roller, a fixing nip portion is formed between the outer peripheral surface of the pressure roller and the outer peripheral surface of the fixing belt. Then, when the pressure roller is rotated by the driving device in a state where the fixing nip is formed, the fixing belt is rotated in the circumferential direction by the rotation of the pressure roller, and further, when the induction heating unit is operated, the fixing is performed. The belt will be heated.

  Therefore, when a recording medium on which an unfixed toner image is formed and supported with the fixing belt heated and the pressure roller and the fixing belt rotating is introduced into the fixing nip portion described above, The toner image is fixed on the recording medium by receiving heat and pressure.

  Each of both edge portions on the inner peripheral surface of the fixing belt is provided with a guide member that extends over the entire circumference in the circumferential direction of the fixing belt and protrudes inward in the radial direction of the fixing belt. This guide member is for preventing the position of the rotating fixing belt from being greatly displaced in the axial direction.

  That is, when the position of the rotating fixing belt is displaced in the axial direction, one of the guide members comes into contact with the peripheral edge of the end surface of the roller member described above to suppress the movement of the fixing belt in the axial direction. Yes.

  In addition to this, when the fixing belt is wound around the support roller, regulating members that face each other at a predetermined interval are arranged on both edges of the outer peripheral surface of the fixing belt. This restricting member is for preventing the guide member from riding on the outer peripheral surface of the support roller.

  In other words, when the fixing belt rotates, when one of the guide members comes into contact with the peripheral edge of the end surface of the support roller and shifts outward in the radial direction of the support roller, one of the outer peripheral surface edges of the fixing belt becomes the regulating member. The guide member is prevented from riding on the outer peripheral surface of the support roller.

  However, in the fixing device described above, since the fixing member for position fixing is in contact with the outer peripheral surface of the rotating fixing belt, there is a concern that the durability of the fixing belt may be reduced.

  SUMMARY An advantage of some aspects of the invention is that it provides a fixing device and an image forming apparatus that can ensure the durability of a fixing belt.

  In order to achieve the above object, the fixing device according to the present invention includes an endless fixing belt having flexibility, an axial direction of the fixing belt, and an outer side in the radial direction of the fixing belt. A pressure roller that presses the fixing belt inward in the radial direction; and an axial roller that extends in the axial direction of the fixing belt and that is disposed radially inward of the fixing belt, and is pressed through the fixing belt by the pressing roller. A fixing member that is in contact with the pressure roller and forms a fixing nip portion for fixing a developer on a recording medium; and extends in the axial direction of the fixing belt, and is disposed radially inward of the fixing belt; A fixing device comprising a cylindrical heating member capable of heating the fixing belt, flange members disposed at both ends of the fixing belt, and an annular rotating body attached to the flange member The fixing belt has a total length longer than a total length of the heating member, and the flange member includes a support portion and a holding portion, and the support portion is fixed to the fixing belt from the outside of the fixing belt. It is configured to enter the inside of the end portion of the belt, and has a regulating surface facing the end surface of the heating member, and the holding portion is configured to protrude from the support portion and enter the inside of the end portion of the heating member, The rotating body is attached to the support portion so as to be rotated in the circumferential direction, and is configured to face the end surface of the fixing belt.

  According to the present invention, it is possible to provide a fixing device and an image forming apparatus that can ensure the durability of the fixing belt.

1 is a schematic configuration diagram showing an image forming apparatus equipped with a fixing device according to an embodiment of the present invention. 1 is a partial cross-sectional view of a fixing device according to an embodiment of the present invention. 2A and 2B are a perspective view and a side view of a fixing belt constituting a fixing device according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of a heating member, a fixing belt, a rotating body, and a flange member constituting a first example of a fixing device according to an embodiment of the present invention. It is a perspective view of the flange member which constitutes the 2nd example of the fixing device concerning the embodiment of the present invention. FIG. 6 is a cross-sectional view of a heating member, a fixing belt, a rotating body, and a flange member that constitute a third example of a fixing device according to an embodiment of the present invention. FIG. 6 is a cross-sectional view of a heating member, a fixing belt, a rotating body, a flange member, and a sliding member that constitute a fourth example of a fixing device according to an embodiment of the present invention. FIG. 6 is a cross-sectional view of a heating member, a fixing belt, a rotating body, a flange member, and a sliding member that constitute a fourth example of a fixing device according to an embodiment of the present invention. FIG. 9 is a view of a flange member and a sliding member constituting a fourth example of the fixing device according to the embodiment of the present invention when viewed in the fixing belt axial direction. FIG. 10 is a cross-sectional view of a heating member, a fixing belt, a rotating body, and a flange member that constitute a fifth example of a fixing device according to an embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  First, an image forming apparatus 1 according to an embodiment of the present invention will be described with reference to FIG.

  As shown in FIG. 1, the image forming apparatus 1 is a tandem type color printer. Four toner bottles 102Y, 102M, 102C, and 102K corresponding to the respective colors (yellow, magenta, cyan, and black) are detachably installed in the bottle housing portion 101 that is located in the upper upper portion of the image forming apparatus 1. These toner bottles 102Y, 102M, 102C, and 102K are exchangeable by a user or the like. The fixing device 20 according to the embodiment of the present invention can be applied to any of a facsimile, a copying machine, and a complex machine of these.

  An intermediate transfer unit 85 is disposed below the bottle housing portion 101. Image forming units 4Y, 4M, 4C, and 4K corresponding to the respective colors (yellow, magenta, cyan, and black) are arranged in parallel so as to face the intermediate transfer belt 78 of the intermediate transfer unit 85.

  Photosensitive drums 5Y, 5M, 5C, and 5K are disposed in the image forming units 4Y, 4M, 4C, and 4K, respectively. In addition, around each of the photosensitive drums 5Y, 5M, 5C, and 5K, a charging unit 75, a developing unit 76, a cleaning unit 77, a neutralizing unit (not shown), and the like are disposed. Then, an image forming process (charging process, exposure process, developing process, transfer process, cleaning process) is performed on each of the photoconductive drums 5Y, 5M, 5C, and 5K. An image of each color is formed on 5K.

  The photosensitive drums 5Y, 5M, 5C, and 5K are rotationally driven in a clockwise direction in FIG. 1 by a drive motor (not shown). Then, the surfaces of the photosensitive drums 5Y, 5M, 5C, and 5K are uniformly charged at the position of the charging unit 75 (a charging process). Thereafter, the surfaces of the photosensitive drums 5Y, 5M, 5C, and 5K reach the irradiation position of the laser beam emitted from the exposure unit 3, and electrostatic latent images corresponding to the respective colors are formed by exposure scanning at this position. (This is an exposure process.)

  Thereafter, the surfaces of the photosensitive drums 5Y, 5M, 5C, and 5K reach a position facing the developing unit 76, and the electrostatic latent image is developed at this position to form toner images of each color (development process). .) Thereafter, the surfaces of the photosensitive drums 5Y, 5M, 5C, and 5K reach positions facing the intermediate transfer belt 78 and the primary transfer bias rollers 79Y, 79M, 79C, and 79K, and the photosensitive drums 5Y, 5M are located at this position. The toner images on 5C and 5K are transferred onto the intermediate transfer belt 78 (this is the first transfer step). At this time, a small amount of untransferred toner remains on the photosensitive drums 5Y, 5M, 5C, and 5K.

  Thereafter, the surfaces of the photoconductive drums 5Y, 5M, 5C, and 5K reach a position facing the cleaning unit 77, and untransferred toner remaining on the photoconductive drums 5Y, 5M, 5C, and 5K is removed at this position. 77 is mechanically collected by a cleaning blade (cleaning process).

  Finally, the surfaces of the photosensitive drums 5Y, 5M, 5C, and 5K reach a position facing a neutralization unit (not shown), and the residual potential on the photosensitive drums 5Y, 5M, 5C, and 5K is removed at this position. Is done. Thus, a series of image forming processes performed on the photosensitive drums 5Y, 5M, 5C, and 5K is completed.

  Thereafter, the toner images of the respective colors formed on the respective photosensitive drums through the developing process are transferred onto the intermediate transfer belt 78 in an overlapping manner. In this way, a color image is formed on the intermediate transfer belt 78. Here, the intermediate transfer unit 85 includes an intermediate transfer belt 78, four primary transfer bias rollers 79Y, 79M, 79C, and 79K, a secondary transfer backup roller 82, a cleaning backup roller 83, a tension roller 84, and an intermediate transfer cleaning unit 80. , Etc. The intermediate transfer belt 78 is stretched and supported by three rollers 82 to 84 and is endlessly moved in the direction of the arrow in FIG.

  The four primary transfer bias rollers 79Y, 79M, 79C, and 79K respectively sandwich the intermediate transfer belt 78 between the photosensitive drums 5Y, 5M, 5C, and 5K to form a primary transfer nip. Then, a transfer bias reverse to the polarity of the toner is applied to the primary transfer bias rollers 79Y, 79M, 79C, and 79K. The intermediate transfer belt 78 travels in the direction of the arrow and sequentially passes through the primary transfer nips of the primary transfer bias rollers 79Y, 79M, 79C, and 79K. In this way, the toner images of the respective colors on the photosensitive drums 5Y, 5M, 5C, and 5K are primarily transferred while being superimposed on the intermediate transfer belt 78.

  Thereafter, the intermediate transfer belt 78 onto which the toner images of the respective colors are transferred in an overlapping manner reaches a position facing the secondary transfer roller 89. At this position, the secondary transfer backup roller 82 sandwiches the intermediate transfer belt 78 between the secondary transfer roller 89 and forms a secondary transfer nip. The four color toner images formed on the intermediate transfer belt 78 are transferred onto the recording medium P conveyed to the position of the secondary transfer nip. At this time, untransferred toner that has not been transferred to the recording medium P remains on the intermediate transfer belt 78. Thereafter, the intermediate transfer belt 78 reaches the position of the intermediate transfer cleaning unit 80. At this position, the untransferred toner on the intermediate transfer belt 78 is collected. Thus, a series of transfer processes performed on the intermediate transfer belt 78 is completed.

  Here, the recording medium P transported to the position of the secondary transfer nip is fed from the paper feeding unit 12 disposed below the inside of the image forming apparatus 1 via the paper feeding roller 97 and the registration roller pair 98. It has been transported. Specifically, the paper feed unit 12 stores a plurality of recording media P such as transfer papers. When the paper feed roller 97 is driven to rotate counterclockwise in FIG. 1, the uppermost recording medium P is fed between the rollers of the registration roller pair 98.

  The recording medium P conveyed to the registration roller pair 98 is temporarily stopped at the position of the roller nip of the registration roller pair 98 that has stopped rotating. Then, the registration roller pair 98 is rotationally driven in synchronization with the color image on the intermediate transfer belt 78, and the recording medium P is conveyed toward the secondary transfer nip. In this way, a desired color image is transferred onto the recording medium P.

  Thereafter, the recording medium P on which the color image is transferred at the position of the secondary transfer nip is conveyed to the position of the fixing device 20. At this position, the color image transferred to the surface is fixed on the recording medium P by heat and pressure generated by the fixing belt 21 and the pressure roller 31. Thereafter, the recording medium P is discharged to the outside of the image forming apparatus 1 through a pair of paper discharge rollers 99. The recording medium P discharged to the outside of the image forming apparatus 1 by the discharge roller pair 99 is sequentially stacked on the stack unit 100 as an output image. Thus, a series of image forming processes in the image forming apparatus 1 is completed.

  Next, the configuration of the fixing device 20 according to the present embodiment will be described.

  As shown in FIG. 2, the fixing device 20 includes a fixing belt 21, a heating member 22, a fixing member 23, a support member 24, a heater 25, a temperature sensor 26, and a pressure roller 31.

  As shown in FIG. 3, the fixing belt 21 is a thin and flexible endless belt, and rotates in the direction of arrow A in FIG. The fixing belt 21 is formed such that a base material layer, an elastic layer, and a release layer are sequentially laminated from an inner peripheral surface 21a facing a fixing member 23, which will be described later, to an outside, and the total thickness is 1 mm or less. Has been.

  The base material layer of the fixing belt 21 has a layer thickness of 30 to 100 μm, and is formed of a metal material such as nickel alloy or stainless steel, or a resin material such as polyimide.

  The elastic layer of the fixing belt 21 has a layer thickness of 100 to 300 μm and is formed of a rubber material such as silicone rubber, foamable silicone rubber, or fluorine rubber. By providing this elastic layer, minute irregularities on the surface of the fixing belt 21 in the fixing nip N, which will be described later, are not formed, and heat is uniformly transmitted to the toner (toner image) on the recording medium P, thereby generating a crushed skin image. Has been deterred.

  The release layer of the fixing belt 21 has a layer thickness of 10 to 50 μm, and includes PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), PTFE (polytetrafluoroethylene), polyimide, polyetherimide, PES ( (Polyether sulfide) and the like. By providing this release layer, the releasability (peelability) for the toner (toner image) is secured.

  The diameter of the fixing belt 21 is preferably set to 15 to 120 mm. In the present embodiment, the diameter of the fixing belt 21 is set to about 30 mm. The fixing belt 21 may be a film using a metal material such as nickel alloy or stainless steel, or a resin material such as polyimide.

  A heating member 22, a fixing member 23, a support member 24, and a heater 25 are disposed inside the fixing belt 21. Further, flange members 40A, 40B, 40C, 40D, 40E, and 40F as shown in FIGS. 4 to 10 are disposed at both ends of the fixing belt 21.

  The heating member 22 is a cylindrical body that extends parallel to the axial direction of the fixing belt 21 and has a substantially circular cross-sectional shape, and is formed of a metal such as an aluminum alloy, steel, or stainless steel. Here, the axial direction of the fixing belt 21 is a direction parallel to the image fixing surface of the recording medium P and orthogonal to the moving path of the recording medium P (see FIG. 3).

  When the heating member 22 is viewed in the axial direction of the fixing belt 21, the heating member 22 is surrounded by the fixing belt 21 in the circumferential direction. The thickness of the heating member 22 is desirably set to 0.2 mm or less. This is to efficiently transmit heat energy generated by the heater 25 described later to the fixing belt 21. Moreover, the cross-sectional shape of the heating member 22 may be a polygon.

  Further, a lubricant such as fluorine grease or silicone oil is interposed between the outer peripheral surface 22a of the heating member 22 and the inner peripheral surface 21a of the fixing member 21, and when the fixing belt 21 rotates in the circumferential direction. The frictional resistance generated between the fixing belt 21 and the heating member 22 is reduced.

  The fixing member 23 extends parallel to the axial direction of the fixing belt 21 and is disposed between the heating member 22 and the fixing belt 21. In the fixing member 23, at least a portion facing the inner peripheral surface 21 a of the fixing belt 21 is formed of a heat-resistant material such as a liquid crystal polymer, polyamideimide, or polyimide resin.

  Further, in the fixing member 23, a portion facing the inner peripheral surface 21a of the fixing belt 21 becomes a concave curved surface 23a having a radius of 25 to 120 mm along the curvature of the outer peripheral surface of the outer peripheral surface 31a of the pressure roller 31 described later. ing.

  The support member 24 extends in parallel to the axial direction of the fixing belt 21 and is located inward of the heating member 22 when viewed in the axial direction of the fixing belt 21. The support member 24 is made of a metal such as stainless steel.

  Both ends of the support member 24 protrude outward from the heating member 22 and the fixing belt 21 and are supported by side plates (not shown). A fixing member 23 is attached to the support member 24, and a concave curved surface 23 a of the fixing member 23 is in contact with the inner peripheral surface 21 a of the fixing belt 21.

  The heater 25 is a halogen heater, a carbon heater, or the like, and is disposed inside the heating member 22. Electric power is supplied to the heater 25 from a power supply unit (not shown), and the fixing belt 21 is heated via the heating member 22.

  Both ends of the heater 25 protrude outward from the heating member 22 and the fixing belt 21 and are supported by side plates (not shown). Furthermore, in order to prevent the support member 24 from being heated by the radiant heat of the heater 25 or the like, the surface is heat-insulated or mirror-finished, and wasted energy due to the support member 24 being heated. Consume consumption.

  The temperature sensor 26 is installed so as to face the outer peripheral surface 21b of the fixing belt 21, and is constituted by a known thermistor or the like. The temperature sensor 26 is located in the central region of the fixing belt 21 in the axial direction. Based on the temperature of the fixing belt 21 detected by the temperature sensor 26, a control unit (not shown) sends the heater 25 to the heater 25. The power supplied is adjusted.

  The pressure roller 31 extends parallel to the axial direction of the fixing belt 21, and the outer peripheral surface 31 a is disposed so as to contact the outer peripheral surface 21 b where the fixing member 23 is in contact with the fixing belt 21. A fixing nip portion N is formed between the fixing belt 31 and the fixing belt 21.

  The pressure roller 31 is pressed toward the fixing belt 21 by a spring or the like (not shown), and is rotationally driven in the direction of arrow B in FIG. 2 by a drive mechanism (not shown). Further, both end portions in the axial direction of the pressure roller 31 are rotatably supported by side plates (not shown) via bearings.

  As a result, the fixing belt 21 is sandwiched between the outer peripheral surface 31a of the pressure roller 31 and the concave curved surface 23a of the fixing member 23, and when the pressure roller 31 is rotated in the direction of arrow B in FIG. The fixing belt 21 is rotated in the direction of arrow A in FIG.

  At this time, tension is applied to the fixing belt 21 on the inlet side of the fixing nip portion N, that is, below the fixing nip portion N in FIG. 2, and the recording medium P is guided to the fixing nip portion N. .

  Therefore, the recording medium P on which the unfixed toner (toner image) is formed and carried in the state where the fixing belt 21 is heated and the pressure roller 31 and the fixing belt 21 are rotated is fed to the fixing nip portion N. When introduced, the toner T on the recording medium P receives heat and pressure and is fixed on the recording medium P.

  Further, a separation plate (not shown) is provided on the exit side of the fixing nip portion N, and the recording medium P delivered from the fixing nip portion N is guided by the separation plate.

  The diameter of the pressure roller 31 in this embodiment is set to 20 to 40 mm. The pressure roller 31 is provided with an elastic layer 33 on the outer peripheral surface of a cylindrical cored bar 32. The elastic layer 33 is made of a material such as foamable silicone rubber, silicone rubber, or fluororubber. Furthermore, a thin release layer formed of PFA, PTFE or the like similar to the fixing belt 21 described above may be provided on the surface of the elastic layer 33.

  When the elastic layer 33 of the pressure roller 31 is formed of foamable silicone, the pressure applied to the fixing nip portion N can be reduced, so that the fixing member 23 is less likely to bend. In addition to this, the heat insulating property of the pressure roller 31 is enhanced and heat is not easily transmitted from the fixing belt 21 to the pressure roller 31, so that the heating efficiency of the fixing belt 21 can be improved.

  Further, when the diameter of the fixing belt 21 is set smaller than the diameter of the pressure roller 31, the curvature of the outer peripheral surface 21 b of the fixing belt 21 in the fixing nip portion N is the curvature of the outer peripheral surface 31 a of the pressure roller 31. Therefore, the recording medium P sent out from the fixing nip N is easily separated from the fixing belt 21.

  As shown in FIG. 4, the flange member 40 </ b> A used in the first example of the fixing device 20 according to the present embodiment includes a support portion 41 and a holding portion 42 and is supported by a side plate (not shown). . Further, a disc-shaped rotating body 44 is attached to the flange member 40A.

  The flange member 40A is formed of a heat-resistant material such as PPS (polyphenylene sulfide), PET (polyethylene terephthalate), PBT (polybutylene terephthalate), PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), or liquid crystal polymer. Has been.

  The support portion 41 is formed in a cylindrical shape and plays a role of supporting the end portion of the fixing belt 21 so that the fixing belt 21 can rotate. The holding portion 42 is formed in a cylindrical shape, and the end of the heating member 22 is supported. The support part 41 and the holding part 42 are located coaxially. Further, the entire length (axial length) of the fixing belt 21 in the fixing device 20 is formed longer than the entire length (axial length) of the heating member 22.

  The support portion 41 is configured to enter the inside of the end portion of the fixing belt 21 from the outside of the fixing belt 21 so as to be in contact with the inner peripheral surface 21 a of the fixing belt 21, and has a regulating surface 41 a that faces the end surface of the heating member 22. Have.

  In the support portion 41, a disc-shaped stop portion 43 is integrally formed at an end portion on the side opposite to the regulating surface 41 a. The outer diameter of the stop portion 43 is formed larger than the diameter of the fixing belt 21.

  The holding portion 42 is configured to protrude from the support portion 41 and enter the inside of the end portion of the heating member 22, and is formed integrally with the support portion 41. The outer diameter of the holding portion 42 is formed smaller than the outer diameter of the support portion 41 by the amount of the regulation surface 41a. And the movement of the heating member 22 in the axial direction is restricted by the regulation surface 41a.

  The rotating body 44 is attached to the support portion 41 and can rotate in the circumferential direction along the outer peripheral surface of the support portion 41. The rotating body 44 is located between the end face of the fixing belt 21 and the restraining portion 43. Furthermore, it is formed of a heat resistant material similar to the flange member 40A described above. In addition, a coating layer made of a fluororesin may be formed on the outer peripheral surface of the support portion 41.

  Hereinafter, the operation of the first example of the fixing device 20 according to the embodiment using the flange member 40A shown in FIG. 4 will be described.

  As shown in FIG. 2, with the fixing nip portion N formed between the outer peripheral surface 31a of the pressure roller 31 and the outer peripheral surface 21b of the fixing belt 21, the pressure roller 31 is moved to the arrow in FIG. When rotated in the B direction, the fixing belt 21 is rotated in the direction of arrow A in FIG. At this time, the end portion of the fixing belt 21 rotates smoothly along the outer peripheral surface of the support portion 41.

  When the position of the rotating fixing belt 21 is shifted in the axial direction and one end surface of the fixing belt 21 is in contact with the surface of the rotating body 44 facing the end surface of the fixing belt 21, the rotating body 44 is fixed to the fixing belt 21. Is rotated in the same direction as the fixing belt 21. The rotating body 44 rotates smoothly along the outer peripheral surface of the support portion 41. Further, the restraining portion 43 prevents the rotating body 44 from being detached from the support portion 41.

  Thus, the rotating body 44 is rotated around the fixing belt 21 and the outer peripheral surface 21b of the fixing belt 21 does not rub against other members, so that the durability of the fixing belt 21 can be ensured.

  In particular, if a coating layer made of a fluororesin is formed on the outer peripheral surface of the support portion 41, the friction generated between the fixing belt 21 and the rotating body 44 and the support portion 41 compared to the case where no coating layer is formed. Since the resistance is reduced, the fixing belt 21 and the rotating body 44 can be rotated more smoothly.

  Further, since the entire length of the fixing belt 21 is formed longer than the entire length of the heating member 22, the lubricant interposed between the outer peripheral surface 22 a of the heating member 22 and the inner peripheral surface 21 a of the fixing member 21 is present. It is difficult for the fixing belt 21 to leak to the outer peripheral surface 21b.

  As shown in FIG. 5, the flange member 40B used in the second example of the fixing device 20 according to the present embodiment includes a support portion 41 and a holding portion 42, and is supported by a side plate (not shown). .

  The flange member 40B is formed of the same heat resistant material as that of the flange member 40A described above. In FIG. 5, the parts denoted by the same reference numerals as those in FIG. 4 represent the same thing. The relative positions of the support portion 41, the holding portion 42, and the restraining portion 43 in the flange member 40B are configured similarly to the flange member 40A.

  The difference between the flange member 40A and the flange member 40B is that, in the flange member 40B, a plurality of concave portions 41b are formed on the outer peripheral surface of the support portion 41 at equal intervals in the circumferential direction. These recesses 41b are open toward the end face of the heating member 22 (see FIG. 4).

  That is, on the outer peripheral surface of the support portion 41, the concave portions 41b and the convex portions (the portions where the concave portions 41b are not formed) alternately face the circumferential direction and face the inner peripheral surface 21a of the fixing belt 21 (see FIG. 4). Will be formed. Further, in the flange member 40B, a coating layer made of a fluororesin may be formed on the outer peripheral surface of the support portion 41 as in the flange member 40A.

  The operation of the second example of the fixing device 20 according to the embodiment using the flange member 40B shown in FIG. 5 will be described below.

  In the fixing device 20, since the plurality of concave portions 41b are provided on the outer peripheral surface of the support portion 41, the area where the outer peripheral surface of the support portion 41 is in contact with the inner peripheral surface 21a of the fixing belt 21 is the flange member 40A shown in FIG. Less than For this reason, when the fixing belt 21 rotates in the circumferential direction, the frictional resistance generated between the fixing belt 21 and the support portion 41 of the flange member 40B can be reduced.

  As shown in FIG. 6, the flange member 40 </ b> C used in the third example of the fixing device 20 according to the present embodiment includes a support portion 41 and a holding portion 42 and is supported by a side plate (not shown). . Furthermore, a disc-shaped annular rotating body 44 is attached to the flange member 40C.

  The flange member 40C is formed of the same heat resistant material as that of the flange member 40A described above, and in FIG. 6, portions denoted by the same reference numerals as those in FIG. 4 represent the same thing. The relative positions of the support portion 41, the holding portion 42, and the restraining portion 43 in the flange member 40C are configured similarly to the flange member 40A. The rotating body 44 is configured in the same manner as that shown in FIG.

  The difference between the flange member 40A and the flange member 40C is that, in the flange member 40C, a groove-shaped inner annular recess 41c extending in the circumferential direction is formed on the outer peripheral surface of the support portion 41 so as to face the inner peripheral surface 21b of the fixing belt 21. It is in the point. Further, also in the flange member 40C, a coating layer made of a fluororesin may be formed on the outer peripheral surface of the support portion 41 as in the flange member 40A.

  The operation of the third example of the fixing device 20 according to the embodiment using the flange member 40C shown in FIG. 6 will be described below.

  In the fixing device 20, when the position of the rotating fixing belt 21 is shifted in the axial direction and one end surface of the fixing belt 21 comes into contact with the rotating body 44 attached to the flange 40 </ b> C, the rotating body 44 is fixed to the fixing belt 21. Is rotated in the same direction as the fixing belt 21.

  As described above, the rotating body 44 attached to the flange member 40C is rotated by the fixing belt 21 and the outer peripheral surface 21b of the fixing belt 21 does not rub against other members, so that the durability of the fixing belt 21 is ensured. In addition, the lubricant is difficult to leak to the outer peripheral surface 21 b of the fixing belt 21.

  Further, since the inner annular recess 41c extending in the circumferential direction is provided on the outer peripheral surface of the support portion 41, the area where the outer peripheral surface of the support portion 41 contacts the inner peripheral surface 21a of the fixing belt 21 is the flange member 40A shown in FIG. Less than For this reason, when the fixing belt 21 rotates in the circumferential direction, it is possible to reduce the frictional resistance generated between the fixing belt 21 and the support portion 41 of the flange member 40C.

  As shown in FIG. 7, the flange member 40D used in the fourth example of the fixing device 20 according to the present embodiment includes a support portion 41 and a holding portion 42, and is supported by a side plate (not shown). . Further, a disc-shaped rotating body 44 is attached to the flange member 40D.

  The flange member 40D is formed of the same heat resistant material as that of the flange member 40A described above, and in FIG. 7, portions denoted by the same reference numerals as those in FIGS. 4 to 6 represent the same thing. The relative positions of the support portion 41, the holding portion 42, and the restraining portion 43 in the flange member 40D are configured similarly to the flange member 40A. The rotating body 44 is configured in the same manner as that shown in FIG.

  The difference between the flange member 40A and the flange member 40D is that, in the flange member 40D, a groove-shaped inner annular recess 41c extending in the circumferential direction is formed on the outer peripheral surface of the support portion 41 so as to face the inner peripheral surface 21b of the fixing belt 21. The sliding member 45 formed in a string shape with a nonwoven fabric is attached to the inner annular recess 41c so that both ends thereof are in contact with each other, and the sliding member 45 can be in contact with the inner peripheral surface 21a of the fixing belt 21. It is in the point. Further, also in the flange member 40D, a coating layer made of a fluororesin may be formed on the outer peripheral surface of the support portion 41 in the same manner as the flange member 40A.

  The operation of the fourth example of the fixing device 20 according to the embodiment using the flange member 40D shown in FIG. 7 will be described below.

  In the fixing device 20, when the position of the rotating fixing belt 21 is shifted in the axial direction and one end surface of the fixing belt 21 comes into contact with the rotating body 44 attached to the flange 40 </ b> D, the rotating body 44 is fixed to the fixing belt 21. Is rotated in the same direction as the fixing belt 21.

  As described above, the rotating body 44 attached to the flange member 40D is rotated around the fixing belt 21 and the outer peripheral surface 21b of the fixing belt 21 does not rub against other members, so that the durability of the fixing belt 21 is ensured. be able to.

  Further, since the sliding member 45 attached to the inner annular recess 41c sucks out the excess lubricant present between the outer peripheral surface 22a of the heating member 22 and the inner peripheral surface 21a of the fixing member 21, the fixing belt Thus, it is possible to reliably prevent the lubricant from leaking to the outer peripheral surface 21 b of 21.

  As shown in FIGS. 8 and 9, the flange member 40 </ b> E used in the fifth example of the fixing device 20 according to the present embodiment includes a support portion 41 and a holding portion 42 and is supported by a side plate (not shown). Has been. Furthermore, a disc-shaped annular rotating body 44 is attached to the flange member 40E.

  The flange member 40E is formed of the same heat resistant material as that of the flange member 40A described above. In FIGS. 8 and 9, the parts denoted by the same reference numerals as those in FIGS. 4 to 7 represent the same thing. The relative positions of the support portion 41, the holding portion 42, and the restraining portion 43 in the flange member 40E are configured similarly to the flange member 40A. The rotating body 44 is configured in the same manner as that shown in FIG.

  The difference between the flange member 40A and the flange member 40E is that, in the flange member 40E, an inner annular recess 41d extending in the circumferential direction is formed on the outer peripheral surface of the support portion 41 so as to face the inner peripheral surface 21b of the fixing belt 21, and the non-woven fabric. The sliding member 45 formed in a string shape is attached to the inner annular recess 41d so that both ends thereof are in contact with each other, and the sliding member 45 can be in contact with the inner peripheral surface 21a of the fixing belt 21. is there.

  Since the inner annular recess 41 d in the support portion 41 is open toward the end face of the heating member 22, the sliding member 45 attached to the inner annular recess 41 d faces the end face of the heating member 22.

The sliding member 45 is (in the direction of the arrow A in FIG. 9) the rotation direction of the fixing belt 21 towards the thickness t ₁ of the end portion located on the downstream side, the thickness of the end located upstream in the rotational direction of the fixing belt 21 t It is configured to be thinner than ₂ .

  Further, also in the flange member 40E, a coating layer made of a fluororesin may be formed on the outer peripheral surface of the support portion 41 in the same manner as the flange member 40A.

  The operation of the fifth example of the fixing device 20 according to the embodiment using the flange member 40E shown in FIGS. 8 and 9 will be described below.

  In the fixing device 20, when the position of the rotating fixing belt 21 is shifted in the axial direction and one end surface of the fixing belt 21 is in contact with the rotating body 44 attached to the flange 40E, the rotating body 44 is fixed to the fixing belt 21. Is rotated in the same direction as the fixing belt 21.

  Thus, the rotating body 44 attached to the flange member 40E is rotated around the fixing belt 21, and the outer peripheral surface 21b of the fixing belt 21 does not rub against other members, so that the durability of the fixing belt 21 is ensured. be able to.

  Further, since the sliding member 45 attached to the inner annular recess 41d sucks out the excess amount of lubricant interposed between the outer peripheral surface 22a of the heating member 22 and the inner peripheral surface 21a of the fixing member 21, the fixing belt Thus, it is possible to reliably prevent the lubricant from leaking to the outer peripheral surface 21 b of 21.

Further, the thickness t _{1 of the} end portion of the sliding member 45 located on the downstream side in the rotation direction of the fixing belt 21 is larger than the thickness t _{2 of the} end portion of the sliding member 45 located on the upstream side of the fixing belt 21 in the rotation direction. Since the thickness is reduced, when the fixing belt 21 rotates in the direction of arrow A in FIG. 9, the end portion of the sliding member 45 located downstream in the rotation direction of the fixing belt 21 is the inner circumference of the fixing belt 21. It can be prevented from being pulled off the support portion 41 by being dragged by the surface 21a.

  As shown in FIG. 10, the flange member 40F used in the sixth example of the fixing device 20 according to the present embodiment includes a support portion 41 and a holding portion 42, and is supported by a side plate (not shown). . Furthermore, a disc-shaped rotating body 44 is attached to the flange member 40F.

  The flange member 40F is formed of the same heat resistant material as that of the flange member 40A described above, and in FIG. 10, portions denoted by the same reference numerals as those in FIGS. 4 to 9 represent the same thing. The relative positions of the support portion 41, the holding portion 42, and the restraining portion 43 in the flange member 40F are configured similarly to the flange member 40A. The rotating body 44 is configured in the same manner as that shown in FIG.

  The difference between the flange member 40A and the flange member 40F is that, in the flange member 40F, a groove-shaped inner annular recess 41c extending in the circumferential direction is formed on the outer peripheral surface of the support portion 41 so as to face the inner peripheral surface 21b of the fixing belt 21. The outer annular recess 41e is formed in a circumferentially extending groove shape on the outer peripheral surface of the support portion 41 so as to be located outside the fixing belt 21, and the rotating body 44 is rotated in the circumferential direction on the outer annular recess 41e. It is in the point fitted together.

  The inner diameter of the rotating body 44 is formed to be smaller than the outer diameter of the support portion 41, and the outer diameter of the outer annular groove portion 41e is formed to be equal to the outer diameter of the inner annular groove portion 41c. Further, in order to fit the rotating body 44 to the outer annular recess 41e, the rotating body 44 is constituted by a pair of partial annular bodies that are split into two.

  Further, also in the flange member 40F, a coating layer made of a fluororesin may be formed on the outer peripheral surface of the support portion 41 in the same manner as the flange member 40A.

  The operation of the sixth example of the fixing device 20 according to the embodiment using the flange member 40F shown in FIG. 10 will be described below.

  In the fixing device 20, when the position of the rotating fixing belt 21 is shifted in the axial direction and one end surface of the fixing belt 21 comes into contact with the rotating body 44 attached to the flange 40 </ b> F, the rotating body 44 is fixed to the fixing belt 21. Is rotated in the same direction as the fixing belt 21.

  In this way, the rotating body 44 attached to the flange member 40F is rotated around the fixing belt 21 and the outer peripheral surface 21b of the fixing belt 21 does not rub against other members, so that the durability of the fixing belt 21 is ensured. In addition, the lubricant is difficult to leak to the outer peripheral surface 21 b of the fixing belt 21.

  In addition, since the inner diameter of the rotating body 44 is formed to be smaller than the outer diameter of the support portion 41, the end of the fixing belt 21 faces the rotating body 44. Thereby, the end portion of the fixing belt 21 is not caught in the inner peripheral portion of the rotating body 44.

  A sliding member 45 (see FIG. 7) is attached to the inner annular recess 41c so that the sliding member 45 can come into contact with the inner peripheral surface 21a of the fixing belt 21, and the outer peripheral surface 22a of the heating member 22 and the fixing member are fixed. If the sliding member 45 sucks up the excess lubricant interposed between the inner peripheral surface 21a of the member 21 and the lubricant 21 is reliably prevented from leaking to the outer peripheral surface 21b of the fixing belt 21. it can.

DESCRIPTION OF SYMBOLS 20 Fixing device 21 Fixing belt 22 Heating member 23 Fixing member 31 Pressure roller 40A, 40B, 40C, 40D, 40E, 40F Flange member 41 Support part 41a Restricting surface 41b Recessed part 41c, 41d Inner annular recessed part 41e Outer annular recessed part 42 Holding part 44 Rotating body 45 Sliding member

JP 2007-286080 A

Claims (10)

An endless fixing belt having flexibility;
A pressure roller that extends in the axial direction of the fixing belt and is arranged on the radially outer side of the fixing belt, and presses the fixing belt toward the radially inner side;
It extends in the axial direction of the fixing belt and is arranged radially inside the fixing belt, contacts the pressure roller through the fixing belt by pressing the pressure roller, and fixes the developer on the recording medium. A fixing member that forms a fixing nip portion for
A cylindrical heating member that extends in the axial direction of the fixing belt and that is disposed on the radially inner side of the fixing belt and can heat the fixing belt;
Flange members disposed at both ends of the fixing belt;
A fixing device including an annular rotating body attached to the flange member,
The total length of the fixing belt is formed longer than the total length of the heating member,
The flange member includes a support part and a holding part,
The support portion is configured to enter the inside of the end portion of the fixing belt from the outside of the fixing belt, and has a regulating surface facing the end surface of the heating member,
The holding part is configured to protrude from the support part and enter into the end of the heating member,
The fixing device, wherein the rotating body is attached to a support portion so as to be rotated in a circumferential direction, and is configured to face an end surface of the fixing belt.   The fixing device according to claim 1, wherein the flange member is formed of a heat resistant material.   3. The outer peripheral surface of the support portion of the flange member is formed such that concave portions and convex portions are alternately formed in the circumferential direction so as to face the inner peripheral surface of the fixing belt. Fixing device.   3. The inner circumferential recess extending in the circumferential direction is formed on the outer peripheral surface of the support portion of the flange member so as to face the inner peripheral surface of the fixing belt. Fixing device.   The fixing device according to claim 4, wherein a sliding member made of a nonwoven fabric is attached to the inner annular recess.   The sliding member is formed in a string shape, and is attached to the inner annular recess so that both ends thereof are in contact with each other, and the thickness at both ends of the sliding member is located downstream in the rotation direction of the fixing belt. The fixing device according to claim 5, wherein the end portion is configured to be thinner than an end portion located upstream in the rotation direction of the fixing belt.   An outer annular recess extending in the circumferential direction is formed on an outer peripheral surface of the support portion of the flange member so as to be located outside the fixing belt, and an inner diameter of the rotating body is an outer diameter of the support portion. The fixing device according to any one of claims 1 to 6, wherein the fixing device is formed so as to be smaller than the outer annular recess, and the rotating body is fitted in the outer annular recess so as to be rotatable in a circumferential direction.   The fixing device according to claim 1, wherein a coating layer made of a material having a low friction coefficient is formed on an outer peripheral surface of the support portion in the flange member.   The fixing device according to claim 8, wherein the coating layer is formed of a fluororesin layer.   An image forming apparatus comprising the fixing device according to claim 1.

Images