JP2016102827A - Fixation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixation device capable of suppressing damage to an endless belt.SOLUTION: A fixation device comprises: an endless belt 51; a nip plate 52; a pressure roller PR that sandwiches the endless belt 51 between the nip plate 52 and the pressure roller PR; a heater HTR that generates heat inside the endless belt 51; and a reflection plate 56 that reflects the heat from the heater HTR. The reflection plate 56 includes a reflection part 56C and a downstream extension part 52B that extends from a downstream end of the reflection part 56C toward the pressure roller PR and has a tip. The nip plate 52 includes a center part 52C that sandwiches the endless belt 51 between the pressure roller PR and the center part 52C and a downstream extension part 52B that extends from a downstream end of the center part 52c and extends in a direction away from the pressure roller PR. The downstream extension part 52B of the nip plate 52 is disposed downstream of the tip of the downstream extension part 56B of the reflection plate 56 and includes a downstream cover that covers the tip of the downstream extension part 56B of the reflection plate 56.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a fixing device for fixing a developer on a recording sheet.

  Conventionally, as a fixing device, an endless belt is sandwiched between a pressure roller and a nip member that is in contact with the inner peripheral surface of the endless belt, and a recording sheet is placed in a nip formed between the endless belt and the pressure roller. There is known one in which a developer image is thermally fixed on a recording sheet by being conveyed in a predetermined conveyance direction.

  For example, as disclosed in Patent Document 1, such a fixing device is disposed between a heater that generates heat inside the endless belt and a nip member and the heater, and heat from the heater is transferred to the inner periphery of the endless belt. And a reflecting member that reflects toward the surface.

  The reflecting member includes a reflecting portion having a reflecting surface that reflects heat from the heater, an upstream extending portion extending from the upstream end of the reflecting portion in the transport direction toward the pressure roller, and the reflecting portion in the transport direction. A downstream extension extending from the downstream end toward the pressure roller.

  On the other hand, the nip plate includes a central portion that sandwiches the endless belt between the pressure rollers, an upstream extending portion that extends from the upstream end of the central portion in the conveying direction and extends away from the pressure roller, and a central portion. A downstream extending portion extending from the downstream end in the conveying direction and extending away from the pressure roller.

  And the upstream extension part and downstream extension part of a reflection member are arrange | positioned so that the upstream extension part and downstream extension part of a nip board may be pinched | interposed in the said conveyance direction.

US Patent Publication 2012/0008971 (FIG. 23)

  With the above conventional configuration, the tip of the downstream extending portion of the reflecting plate faces in the direction substantially opposite to the rotation direction of the endless belt and faces the inner peripheral surface of the endless belt.

  For this reason, for example, when the endless belt rotates and the paper behavior after passing through the nip becomes unstable and a paper jam occurs, the inner peripheral surface of the endless belt and the tip of the downstream extension of the reflector come into contact with each other. In addition, the endless belt may be damaged.

  SUMMARY An advantage of some aspects of the invention is that it provides a fixing device capable of suppressing breakage of an endless belt.

  In order to solve the above-described problems, a fixing device according to the present invention includes an endless belt, a nip member that contacts an inner peripheral surface of the endless belt, and the endless belt sandwiched between the endless belt. And a backup member for forming a nip.

  Furthermore, the fixing device may include a heater that generates heat inside the endless belt, and a reflector that reflects heat from the heater.

  Further, the reflection plate has a reflection portion that has a reflection surface that reflects heat from the heater, and a downstream extension portion that extends from the downstream end of the reflection portion in the transport direction toward the backup member and has a tip. , May be included.

  Further, the nip member includes a central portion that sandwiches the endless belt with the backup member, and a downstream extending portion that extends from the downstream end of the central portion in the transport direction and extends away from the backup member. , May be included.

  The downstream extension part of the nip member is arranged downstream in the transport direction with respect to the tip of the downstream extension part of the reflector, and covers a tip of the downstream extension part of the reflector. May have a part.

  According to the present invention, since the tip of the downstream extension portion of the reflector is covered with the downstream cover portion of the nip member, the inner peripheral surface of the endless belt and the tip of the downstream extension portion come into strong contact, and the endless belt is It is possible to suppress damage.

Schematic diagram of printer 1 Center sectional view of the fixing device 5 Exploded perspective view of the fixing device 5 The perspective view which looked at the structure ASSY from the downstream of the conveyance direction (FD) The perspective view which looked at the structure ASSY from the upstream of the conveyance direction (FD) The exploded perspective view which looked at structure ASSY from the downstream of the conveyance direction (FD) Central cross-sectional view of insulation 55 The perspective view which looked at the heat insulating material 55 from the upstream in a conveyance direction (FD) The downstream extension part 52B or the upstream extension part 52A of the nip plate 52 as viewed from the downstream in the transport direction (FD) A view of the downstream extending portion 56B or the upstream extending portion 56A of the reflecting plate 56 as viewed from the downstream in the transport direction (FD).

  An embodiment of the present invention will be described in detail with reference to the drawings as appropriate. In the following description, the outline of the electrophotographic printer 1 provided with the fixing device 5 will be described first, and then the details of the fixing device 5 will be described.

<Schematic Configuration of Printer 1>
First, a schematic configuration of the printer 1 will be described. The printer 1 includes a housing 10 as shown in FIG. The printer 1 further includes a paper feeding device 2, a transfer device 3, an exposure device 4, and a fixing device 5 disposed inside the housing 10. The printer 1 further includes a paper discharge device 9.

  The sheet feeding device 2 includes a tray 21, a pickup roller 23, a sheet feeding roller 241, a driven roller 243 adjacent to the sheet feeding roller 241, a registration roller 251, and a driven roller 253 adjacent to the registration roller 251. I have. The transfer device 3 includes a photosensitive drum 31 and a transfer roller 33 that can form a transfer nip with the photosensitive drum 31. The exposure apparatus 4 includes a semiconductor laser and a lens. The fixing device 5 includes an endless belt 51 and a pressure roller PR capable of forming a fixing nip between the endless belt 51. The paper discharge device 9 includes a paper discharge roller 91, a driven roller 93 adjacent to the paper discharge roller 91, and a paper discharge tray 94. The paper discharge tray 94 is a part of the housing 10.

<Print operation>
Next, the printing operation of the printer 1 will be described. The printer 1 executes this printing operation when power is supplied to the printer 1 and the printer 1 receives a print command.

  When the printer 1 receives the print command, the pickup roller 23 picks up and sends the paper P placed on the tray 21. The paper feed roller 241 and the driven roller 243 further feed the paper P sent from the pickup roller 23 further downstream. The registration roller 251 and the driven roller 253 send the paper P further downstream after adjusting the inclination of the leading edge of the paper P sent from the paper feeding roller 241 and the driven roller 243.

  The exposure device 4 irradiates the photosensitive drum 31 with light to form an electrostatic latent image on the surface of the photosensitive drum 31. This electrostatic latent image is developed by supplying a developer from the developing roller (not shown) to the surface of the photosensitive drum 31 to be a developer image. The transfer roller 33 transfers the developer image formed on the surface of the photosensitive drum 31 onto the paper P conveyed from the registration roller 251 to the transfer nip.

  The fixing device 5 heat-fixes the developer image on the paper P when the transfer device 3 conveys the paper P to the fixing nip formed between the endless belt 51 and the pressure roller PR. The paper discharge roller 91 and the driven roller 93 discharge the paper P conveyed by the fixing device 5 onto the paper discharge tray 94.

<Detailed configuration of fixing device>
Next, the detailed configuration of the fixing device 5 will be described. FIG. 2 is a central sectional view of the fixing device 5, and FIG. 3 is an exploded perspective view of the fixing device 5.

  2 and 3, the fixing device 5 includes an endless belt 51, a heater HTR extending inside the endless belt 51, a stay 53 extending inside the endless belt 51, and an inner circumference of the endless belt 51. A nip plate 52 that can come into contact with the surface, a heat insulating material 55 as an example of a support member that extends inside the endless belt 51, a reflector 56 that extends inside the endless belt 51, and an outer side of the endless belt 51. And a pressure roller PR as an example of a backup member that can rotate around the rotation axis AXIS. The fixing device 5 further includes a spring (not shown) for pressing the stay 53. The fixing device 5 further includes a side guide SG1 and a side guide SG2 for guiding both ends in the longitudinal direction of the inner peripheral surface 51IN of the endless belt 51 (see FIG. 4). P is transported in a predetermined transport direction (FD).

  The endless belt 51 has a base layer and a release layer that covers the surface of the base layer. The base layer may be a metal layer containing SUS (stainless steel) or nickel alloy, or may be a resin layer containing polyimide resin or the like. The base layer may contain various additives. For example, when the base layer is a resin layer, the resin layer may contain a metal, ceramic, carbon, resin, or the like as an additive.

  The release layer is a resin layer containing a fluororesin such as PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer) or PTFE (polytetrafluoroethylene). This release layer may contain carbon or the like as an additive. The endless belt 51 may further include an elastic layer disposed between the base layer and the release layer. The elastic layer may be, for example, a heat resistant silicon rubber layer. The elastic layer may contain carbon, ceramic, or metal as an additive.

  The endless belt 51 has a cylindrical shape, has an inner peripheral surface 51IN and an outer peripheral surface 51OT, and extends along the rotation axis AXIS of the pressure roller PR. The thickness of the endless belt 51 is, for example, in the range of several tens μm to several hundreds μm. The thickness of the endless belt 51 may be, for example, in the range of 5 to 800 μm, in the range of 10 to 500 μm, in the range of 10 to 300 μm, or in the range of 10 to 200 μm. It may be.

  The heater HTR is longer than the endless belt 51 in the longitudinal direction of the endless belt 51 and extends inside the endless belt 51. That is, the longitudinal direction of the heater HTR is substantially parallel to the longitudinal direction of the heat insulating material 55. The heater HTR may be a halogen lamp or a carbon heater. The heater HTR may be an infrared heater. The heater HTR has, for example, a glass tube and a heating element disposed inside the glass tube. Here, the longitudinal direction of the heat insulating material 55 is substantially parallel to the direction (axial direction) in which the rotation axis AXIS of the pressure roller PR extends.

  The nip plate 52 can be in contact with the inner peripheral surface of the endless belt 51 longer than the endless belt 51 in the longitudinal direction of the endless belt 51. The longitudinal direction of the nip plate 52 is substantially parallel to the longitudinal direction of the heat insulating material 55. It is an elastically deformable metal plate such as a SUS (stainless steel) plate or an aluminum plate, and may have an oxide film or a fluororesin film as a surface layer. The plate thickness of the nip plate 52 may be, for example, in the range of 0.05 to 5 mm, in the range of 0.1 to 3 mm, or in the range of 0.5 to 2 mm. However, it may be in the range of 0.9 to 1.5 mm.

  As shown in FIG. 2, the nip plate 52 includes an upstream extension portion 52A, a downstream extension portion 52B arranged downstream of the upstream extension portion 52A in the transport direction (FD), an upstream extension portion 52A, and a downstream portion. A central portion 52C connecting the extending portion 52B.

  As shown in FIG. 2, the center portion 52C of the nip plate 52 extends from the upstream side to the downstream side of the heater HTR in the transport direction (FD). The upstream extension portion 52A extends from the upstream end of the central portion 52C in the transport direction (FD) and extends away from the pressure roller PR. The downstream extension part 52B extends from the downstream end of the central part 52C in the transport direction (FD) and extends in a direction away from the pressure roller PR. With the above-described configuration, the nip plate 52 forms a recess that is recessed in the direction toward the fixing nip NIP, and has a substantially U shape.

  The reflector 56 is longer than the endless belt 51 in the longitudinal direction of the endless belt 51, and is disposed between the heater HTR and the nip plate 52, as shown in FIG. 2, and includes an upstream extension 56A and an upstream extension. The downstream extension part 56B arrange | positioned downstream in the conveyance direction (FD) of 56A, and the reflection part 56C which connects the upstream extension part 56A and the downstream extension part 56B are provided. That is, the longitudinal direction of the reflecting plate 56 is substantially parallel to the longitudinal direction of the endless belt 51. The reflection plate 56 is a metal plate such as an aluminum plate or a SUS (stainless steel) plate, and at least a surface facing the heater HTR is mirror-finished. The thickness of the reflection plate 56 may be, for example, in the range of 0.05 to 5 mm, in the range of 0.1 to 3 mm, or in the range of 0.5 to 2 mm. However, it may be in the range of 0.9 to 1.5 mm.

  As shown in FIG. 2, the reflection portion 56 </ b> C of the reflection plate 56 extends from the upstream side to the downstream side of the heater HTR in the transport direction (FD). Reflecting portion 56 </ b> C has a reflecting surface that is opposed to heater HTR and reflects radiant heat from heater HTR toward inner peripheral surface 51 </ b> IN of endless belt 51. The upstream extending portion 56A extends in the direction from the upstream end in the transport direction (FD) of the reflecting portion 56C toward the pressure roller PR. The downstream extension part 56B extends in the direction from the downstream end in the transport direction (FD) of the reflection part 56C toward the pressure roller PR.

  With the above-described configuration, the reflection plate 56 forms a recess that is recessed in a direction away from the fixing nip NIP, and has a substantially U shape. Further, the reflection plate 56 is disposed so as to cover most of the stay 53. The most part of the stay 53 and the most part of the heat insulating material 55 are disposed between the nip plate 52 and the reflection plate 56 and are surrounded by the nip plate 52 and the reflection plate 56.

  As shown in FIG. 2, the stay 53 is disposed between the reflection plate 56 and the nip plate 52, and includes an upstream wall 53A and a downstream wall 53B disposed downstream in the transport direction (FD) of the upstream wall 53A. And a central wall 53C that connects the upstream wall 53A and the downstream wall 53B.

  As shown in FIG. 2, the central wall 53C of the stay 53 extends from the upstream side to the downstream side of the heater HTR in the transport direction (FD). The dimension of the central wall 53C of the stay 53 in the transport direction (FD) is smaller than the dimension of the reflector 56C of the reflector 56 in the transport direction (FD). The upstream wall 53A of the stay 53 extends from the upstream end in the transport direction (FD) of the central wall 53C and extends away from the pressure roller PR. The downstream wall 53B of the stay 53 extends from the downstream end of the central wall 53C in the transport direction (FD) and extends away from the pressure roller PR. With the above-described configuration, the stay 53 forms a recess that is recessed in the direction toward the fixing nip NIP, and has a substantially U shape.

  The stay 53 is a metal frame such as a SUS (stainless steel) frame, an aluminum frame, or an iron frame, and has higher rigidity than the nip plate 52 and the heat insulating material 55. The thicknesses of the upstream wall 53A, the downstream wall 53B, and the central wall 53C of the stay 53 may be, for example, in the range of 2.0 to 25 mm, in the range of 5.0 to 15 mm, The range of 0.9-10 mm may be sufficient, and the range of 1.0-9.0 mm may be sufficient. 3, the stay 53 is longer than any of the endless belt 51, the nip plate 52, the reflection plate 56, the heater HTR, and the heat insulating material 55 in the longitudinal direction of the endless belt 51. That is, the longitudinal direction of the stay 53 is substantially parallel to the longitudinal direction of the endless belt 51.

  The pressure roller PR has a shaft SFT and an elastic layer EST that covers most of the shaft SFT, and can rotate around the rotation axis AXIS as shown in FIG. It is possible to form the fixing nip NIP with the endless belt 51 by sandwiching the endless belt 51 with the nip plate 52.

  As shown in FIG. 2, the heat insulating material 55 is sandwiched between the stay 53 and the nip plate 52, and the upstream wall 55A and the downstream wall 55B disposed downstream in the transport direction (FD) of the upstream wall 55A. And a central wall 55C that connects the upstream wall 55A and the downstream wall 55B.

  As shown in FIG. 2, the central wall 55C of the heat insulating material 55 extends from the upstream side to the downstream side of the heater HTR in the transport direction (FD). The dimension of the central wall 55C of the heat insulating material 55 in the transport direction (FD) is larger than the dimension of the central wall 53C of the stay 53 in the transport direction (FD). The upstream wall 55A of the heat insulating material 55 extends from the upstream end in the transport direction (FD) of the central wall 55C and extends away from the pressure roller PR. The downstream wall 55B extends from the downstream end of the central wall 53C in the transport direction (FD) and extends away from the pressure roller PR.

  As shown in FIG. 2, the heat insulating material 55 is disposed inside the recess formed by the reflecting plate 56. The stay 53 is disposed inside the recess formed by the heat insulating material 55, and the stay 53 is fitted in the recess formed by the heat insulating material 55. The heat insulating material 55 is supported.

  The central wall 55 </ b> C of the heat insulating material 55 is disposed in a recess formed by the nip plate 52. The central wall 55 </ b> C of the heat insulating material 55 has an upstream support surface 551 that supports the central portion 52 </ b> C of the nip plate 52 and a downstream support surface 553. The downstream support surface 553 is disposed away from the upstream support surface 551 downstream in the transport direction (FD). The central wall 55 </ b> C of the heat insulating material 55 has a recess 555 that is recessed in a direction away from the nip plate 52 between the upstream support surface 551 and the downstream support surface 553. The recess 555 is spaced from the central portion 52C of the nip plate 52, and forms a gap between the central portion 52C of the nip plate 52.

  The heat insulating material 55 is a member that is less rigid than the stay 53 and the nip plate 52 and has a low heat conductivity (low thermal conductivity), and is a heat-resistant resin frame such as a fluorine resin frame or an LCP (Liquid Crystal Plastic) frame. . The thicknesses of the upstream wall 55A, the downstream wall 55B, and the central wall 55C of the heat insulating material 55 may be, for example, in the range of 2.0 to 25 mm, or in the range of 5.0 to 15 mm. 0.9 to 10 mm or 1.0 to 9.0 mm.

<Detailed Configuration of Reflector 56, Nip Plate 52, and Heat Insulating Material 55>
FIG. 4 is a perspective view of the assembled reflection plate 56, nip plate 52, and heat insulating material 55 as viewed from the downstream in the transport direction (FD). FIG. 5 is a perspective view of the assembled reflection plate 56, nip plate 52, and heat insulating material 55 as viewed from the upstream in the transport direction (FD).

  As shown in FIGS. 4 and 5, the reflector 56, the nip plate 52 and the heat insulating material 55 are assembled into an integral structure ASSY. The stay 53 is also assembled to the structure ASSY together with the nip plate 52 and the heat insulating material 55, but the stay 53 is omitted in FIGS. 4 and 5 for convenience. The structure ASSY is assembled by fixing the nip plate 52 and the reflection plate 56 to the heat insulating material 55, respectively.

  Next, a detailed configuration of the reflector 56, the nip plate 52, and the heat insulating material 55 for assembling the structure ASSY will be described.

  First, the detailed structure of the heat insulating material 55 for assembling the structure ASSY will be described. FIG. 6 is an exploded perspective view of the structure ASSY as viewed from the downstream side in the transport direction (FD), and FIG. 7 is a central sectional view of the heat insulating material 55. In FIG. 6, the stay 53 is omitted for convenience.

  As shown in FIG. 6, the downstream wall 55 </ b> B of the heat insulating material 55 includes a protrusion 55 </ b> BB to which the downstream extension 56 </ b> B of the reflector 56 and the downstream extension 52 </ b> B of the nip plate 52 are fixed, and the downstream extension of the nip plate 52. And a guide 55BG as an example of a downstream protruding wall that guides the portion 52B.

  As shown in FIG. 6, the protrusion 55 </ b> BB of the heat insulating material 55 includes a first protrusion 55 </ b> BB <b> 1 disposed at the center of the heat insulating material 55 in the longitudinal direction of the heat insulating material 55 and the heat insulating material 55 in the longitudinal direction of the heat insulating material 55. 2nd protrusion 55BB2 arrange | positioned at the one end part. The protrusion 55BB of the heat insulating material 55 further includes a third protrusion 55BB3 disposed at the other end opposite to the one end of the heat insulating material 55 in the longitudinal direction of the heat insulating material 55.

  As shown in FIG. 6, the downstream wall 55 </ b> B of the heat insulating material 55 has a downstream surface 55 </ b> BDS that faces downstream in the transport direction (FD). And each of 1st protrusion 55BB1, 2nd protrusion 55BB2, and 3rd protrusion 55BB3 of the heat insulating material 55 protrudes toward the downstream in a conveyance direction (FD) from this downstream surface 55BDS.

  As shown in FIG. 7, the first protrusion 55BB1 of the downstream wall 55B of the heat insulating material 55 includes a base 55BBB extending downstream from the downstream surface 55BDS in the transport direction (FD) and a downstream in the transport direction (FD) of the base 55BBB. And a bulging portion 55BBE that bulges from the end in a direction orthogonal to the conveyance direction (FD).

  The base 55BBB of the first protrusion 55BB1 has a cylindrical shape, and the bulging portion 55BBE has a truncated cone shape that tapers toward the downstream in the transport direction (FD). That is, the first protrusion 55BB1 has a mushroom shape. Since the second protrusion 55BB2 and the third protrusion 55BB3 also have the same structure as that of the first protrusion 55BB1, the detailed description of the second protrusion 55BB2 and the third protrusion 55BB3 is omitted.

  As shown in FIG. 7, the guide 55BG of the downstream wall 55B of the heat insulating material 55 protrudes downstream in the transport direction (FD) from the downstream surface 55BDS. Further, as shown in FIGS. 2 and 7, the guide 55BG is disposed between the central portion 52C of the nip plate 52 and the distal end of the downstream extension portion 56B of the reflection plate 56. It protrudes toward the upstream surface facing upstream in the transport direction (FD). The guide 55BG includes a first guide 55BG1 disposed at the center of the heat insulating material 55 in the longitudinal direction of the heat insulating material 55 and a second guide disposed at one end of the heat insulating material 55 in the longitudinal direction of the heat insulating material 55. And a guide 55BG2. Further, the protrusion 55BB of the heat insulating material 55 further includes a third guide 55BG3 disposed at the other end opposite to the one end of the heat insulating material 55 in the longitudinal direction of the heat insulating material 55.

  As shown in FIG. 7, the first guide 55BG1 on the downstream wall 55B of the heat insulating material 55 is closer to the pressure roller PR than the first protrusion 55BB1. The first guide 55BG1 is disposed so as to be closer to the pressure roller PR toward the upstream in the transport direction (FD), and is further away from the pressure roller PR than the inclined surface 55BGT. When viewed, it has a positioning surface 55BGV extending toward the base portion 55BBB of the first protrusion 55BB1. The first guide 55BG1 has a positioning surface 55BGV that extends toward the base 55BBB of the first protrusion 55BB1 when viewed from the longitudinal direction of the heat insulating material 55.

  The inclined surface 55BGT of the first guide 55BG1 extends from the downstream end in the transport direction (FD) of the downstream support surface 553 of the heat insulating material 55, and extends in a direction away from the pressure roller PR. The inclined surface 55BGT is inclined with respect to the transport direction (FD). Further, the inclined surface 55BGT is a first end separated from the pressure roller PR, and a second end located closer to the pressure roller PR than the first end and upstream in the transport direction (FD) from the first end. With ends.

  The positioning surface 55BGV extends from one end (downstream end) of the inclined surface 55BGT away from the pressure roller PR, extends substantially perpendicular to the transport direction (FD), and extends in the direction toward the base 55BBB of the first protrusion 55BB1. The positioning surface 55BGV extends to a position slightly closer to the pressure roller PR than the base portion 55BBB of the first protrusion 55BB1.

  Further, as shown in FIG. 7, the positioning surface 55BGV is disposed upstream of the bulging portion 55BBE of the first protrusion 55BB1 in the transport direction (FD). A distance D1 in the transport direction (FD) between the positioning surface 55BGV and the bulging portion 55BBE of the first protrusion 55BB is slightly larger than the thickness of the downstream extending portion 52B of the nip plate 52.

  Further, as shown in FIG. 7, the positioning 55BGV is disposed downstream of the downstream surface 55BDS of the downstream wall 55B in the transport direction (FD). A distance D2 in the transport direction (FD) between the positioning surface 55BGV and the downstream surface 55BDS is slightly larger than the thickness of the downstream extension portion 52B of the reflection plate 56.

  This is because the second guide 55BG2 and the third guide 55BG3 have the same structure as that of the first guide 55BG1 described above. Detailed descriptions of the second guide 55BG2 and the third guide 55BG3 are omitted.

FIG. 8 is a perspective view of the heat insulating material 55 as viewed from the upstream in the transport direction (FD). As shown in FIG. 8, the downstream wall 55 </ b> B of the heat insulating material 55 includes a protrusion 55 </ b> AB to which the upstream extension portion 56 </ b> A of the reflector 56 and the upstream extension portion 52 </ b> A of the nip plate 52 are fixed, and the upstream extension of the nip plate 52. And a guide 55AG as an example of an upstream projecting wall that guides the portion 52A.
As shown in FIG. 8, the protrusion 55 </ b> AB of the heat insulating material 55 includes a first protrusion 55 </ b> AB <b> 1 disposed at the center of the heat insulating material 55 in the longitudinal direction of the heat insulating material 55 and the heat insulating material 55 in the longitudinal direction of the heat insulating material 55. 2nd protrusion 55AB2 arrange | positioned at the one end part. The protrusion 55AB of the heat insulating material 55 further includes a third protrusion 55AB3 disposed at the other end opposite to the one end of the heat insulating material 55 in the longitudinal direction of the heat insulating material 55.

  As shown in FIG. 8, the upstream wall 55 </ b> A of the heat insulating material 55 has an upstream surface 55 </ b> AUS that faces upstream in the transport direction (FD). And each of 1st protrusion 55AB1, 2nd protrusion 55AB2, and 3rd protrusion 55AB3 of the heat insulating material 55 protrudes toward the upstream in a conveyance direction (FD) from this upstream surface 55AUS.

  As shown in FIG. 7, the first protrusion 55AB1 of the upstream wall 55A of the heat insulating material 55 includes a base 55ABB extending upstream from the upstream surface 55ADS in the transport direction (FD) and an upstream in the transport direction (FD) of the base 55ABB. And a bulging portion 55ABE that swells in a direction orthogonal to the transport direction (FD) from the end.

  The base 55ABB of the first protrusion 55AB1 has a cylindrical shape, and the bulging portion 55ABE has a truncated cone shape that tapers toward the upstream in the transport direction (FD). That is, the first protrusion 55AB1 has a mushroom shape. This is because the second protrusion 55AB2 and the third protrusion 55AB3 also have the same structure as that of the first protrusion 55AB1. A detailed description of the second protrusion 55AB2 and the third protrusion 55AB3 is omitted.

  As shown in FIG. 7, the guide 55AG on the upstream wall 55A of the heat insulating material 55 protrudes from the upstream surface 55AUS to the upstream in the transport direction (FD). 2 and 7, the guide 55AG is disposed between the reflecting portion 56C of the reflecting plate 56 and the downstream extending portion 52B of the nip plate 52 at the downstream extending portion 56B of the reflecting plate 56. It protrudes toward the downstream surface facing downstream in the transport direction (FD). The guide 55AG is arranged in the longitudinal direction of the heat insulating material 55, the first guide 55AG1 disposed in the central portion of the heat insulating material 55, and the second guide disposed in one end portion of the heat insulating material 55 in the longitudinal direction of the heat insulating material 55. And a guide 55AG2. Further, the protrusion 55AB of the heat insulating material 55 further includes a third guide 55AG3 disposed at the other end opposite to the one end of the heat insulating material 55 in the longitudinal direction of the heat insulating material 55.

  As shown in FIG. 7, the first guide 55AG1 on the upstream wall 55A of the heat insulating material 55 is farther from the pressure roller PR than the first protrusion 55AB1. The first guide 55AG1 is disposed closer to the pressure roller PR than the inclined surface 55AGT and the inclined surface 55AGT toward the upstream in the transport direction (FD) as it approaches the pressure roller PR, and from the longitudinal direction of the heat insulating material 55. When viewed, it has a positioning surface 55AGV extending toward the base portion 55ABB of the first protrusion 55AB1.

  The inclined surface 55AGT of the first guide 55AG1 extends from the end surface of the upstream wall 55A of the heat insulating material 55 that is farthest from the pressure roller PR, and extends in the direction toward the pressure roller PR. The inclined surface 55AGT is inclined with respect to the transport direction (FD). The inclined surface 55AGT has a first end that is separated from the pressure roller PR, and a second end that is located closer to the pressure roller PR than the first end and upstream in the transport direction (FD) from the first end. With ends.

  The positioning surface 55AGV extends from the other end (upstream end) of the inclined surface 55AGT near the pressure roller PR, extends substantially perpendicular to the transport direction (FD), and extends in the direction toward the base 55ABB of the first protrusion 55AB1. The positioning surface 55AGV extends to a position slightly further from the pressure roller PR than the base portion 55ABB of the first protrusion 55AB1.

  Further, as shown in FIG. 7, the positioning surface 55AGV is disposed downstream of the bulging portion 55ABE of the first protrusion 55AB in the transport direction (FD). A distance D3 in the transport direction (FD) between the positioning surface 55AGV and the bulging portion 55ABE of the first protrusion 55AB is slightly larger than the thickness of the upstream extending portion 56A of the reflecting plate 56.

  Furthermore, as shown in FIG. 7, the positioning 55AGV is disposed upstream in the transport direction (FD) from the upstream surface 55AUS of the upstream wall 55A. A distance D4 in the conveying direction (FD) between the positioning surface 55AGV and the upstream surface 55AUS is slightly larger than the thickness of the upstream extension portion 52A of the nip plate 52.

  Since the second guide 55AG2 and the third guide 55AG3 have the same structure as that of the first guide 55AG1, the detailed description of the second guide 55AG2 and the third guide 55AG3 is omitted.

  Next, a detailed configuration of the nip plate 52 for assembling the structure ASSY will be described.

  FIG. 9 is a view of the downstream extending portion 52B or the upstream extending portion 52A of the nip plate 52 as viewed from the downstream in the transport direction (FD). The downstream extending portion 52B and the upstream extending portion 52A of the nip plate 52 have substantially the same structure when viewed from the downstream in the transport direction (FD). Therefore, the downstream extension part 52B will be described, and the description of the upstream extension part 52A will be omitted.

  As shown in FIG. 9, the downstream extending portion 52B of the nip plate 52 has an edge 52BEG that faces away from the pressure roller PR. The edge 52BEG is a portion farthest from the pressure roller PR of the downstream extending portion 52B, and includes a first edge 52BEG1, a second edge 52BEG2, a third edge 52BEG3, and a third edge 52BEG4.

  The first edge 52BEG1 and the second edge 52BEG2 are arranged at the center in the longitudinal direction of the downstream extension portion 52B in the longitudinal direction of the nip plate 52. The third edge 52BEG3 is disposed at one end portion of the downstream extending portion 52B in the longitudinal direction of the nip plate 52, and the fourth edge 52BEG4 is defined as one end portion of the downstream extending portion 52B in the longitudinal direction of the nip plate 52. Arranged at the other end opposite.

  As shown in FIG. 9, the downstream extending portion 52B of the nip plate 52 has a first notch 52BCT1, a second notch 52BCT2, and a third notch 52BCT3. The first notch 52BCT1 is formed at the center in the longitudinal direction of the nip plate 52 and opens in a direction away from the pressure roller PR. The second notch 52BCT2 is formed at one end in the longitudinal direction of the nip plate 52 and opens in a direction away from the pressure roller. The third notch 52BCT3 is formed at the other end opposite to the one end in the longitudinal direction of the nip plate 52 and opens in a direction away from the pressure roller. The first notch 52BCT1 is disposed between the second notch 52BCT2 and the third notch 52BCT3.

  The first notch 52ECT1 opens between the first edge 52BEG1 and the second edge 52BEG2, and the second notch 52ECT2 opens between the second edge 52BEG2 and the third edge 52BEG3, and the third notch 52ECT3 is opened between the first edge 52BEG1 and the fourth edge 52BEG4.

  As shown in FIG. 9, the downstream extension portion 52 </ b> B of the nip plate 52 has an edge EDG that forms a first notch 52 </ b> BCT <b> 1. The edge EDG includes a first notch edge 52EDG1, a second notch edge 52EDG2, a third notch edge 52EDG3, a fourth notch edge 52EDG4, and a fifth notch edge 52EDG5.

  The first notch edge 52EDG1 and the second notch edge 52EDG2 form an opening that opens in a direction away from the pressure roller PR between the first notch edge 52EDG1 and the second notch edge 52EDG2. The distance between the first notch edge 52EDG1 and the second notch edge 52EDG2 becomes narrower as the pressure roller PR is approached.

  The third notch edge 52EDG3 extends from the end of the second notch edge 52EDG2 that is closest to the pressure roller PR, and extends so as to approach the pressure roller PR. The fourth notch edge 52EDG3 extends from the end of the first notch edge 52EDG1 that is closest to the pressure roller PR, and extends so as to approach the pressure roller PR. The distance between the third notch edge 52EDG3 and the fourth notch edge 52EDG4 increases as the pressure roller PR is approached.

  With the above configuration, the first notch edge 52EDG1, the second notch edge 52EDG2, the third notch edge 52EDG3, and the fourth notch edge 52EDG4 form a constricted shape as shown in FIG. The fifth notch edge EDG5 connects the third notch edge 52EDG3 and the fourth notch edge 52EDG4.

  As shown in FIG. 9, the downstream extension 52B of the nip plate 52 has the same configuration as the first notch 52BCT1 with respect to the second notch 52BCT2 and the third notch 52BCT3, and therefore the second notch 52BCT2 and the third notch 52BCT3. The detailed description about is omitted.

  Next, a detailed configuration of the reflector 56 for assembling the structure ASSY will be described.

  FIG. 10 is a view of the downstream extension 56B or the upstream extension 56A of the reflection plate 56 as viewed from the downstream in the transport direction (FD). The downstream extension 56B and the upstream extension 56A of the reflecting plate 56 have substantially the same structure when viewed from the downstream in the transport direction (FD). Therefore, the downstream extension portion 56B will be described, and the description of the upstream extension portion 56A will be omitted.

  As shown in FIG. 10, the downstream extending portion 56 </ b> B of the reflecting plate 56 has an edge 56 </ b> BEG that faces the pressure roller PR. The edge 56BEG is a portion closest to the pressure roller PR of the downstream extending portion 56B, and includes a first edge 56BEG1, a second edge 56BEG2, a third edge 56BEG3, and a third edge 56BEG4.

  The first edge 56BEG1 and the second edge 56BEG2 are arranged at the center in the longitudinal direction of the downstream extension 56B in the longitudinal direction of the reflector 56. The third edge 56BEG3 is disposed at one end of the downstream extension 56B in the longitudinal direction of the reflector 56, and the fourth edge 56BEG4 is defined as one end of the downstream extension 56B in the longitudinal direction of the reflector 56. Arranged at the other end opposite.

  The first edge 56BEG1 is disposed between the second edge 56BEG2 and the third edge 56BEG3, and the second edge 56BEG2 is disposed between the first edge 56BEG1 and the fourth edge 56BEG4.

  As shown in FIG. 10, the downstream extension 56 </ b> B of the reflection plate 56 has a first notch 56 </ b> BCT <b> 1, a second notch 56 </ b> BCT <b> 2, and a third notch 56 </ b> BCT <b> 3. The first notch 56BCT1 is formed at the center in the longitudinal direction of the reflecting plate 56, and opens in the direction toward the pressure roller PR. The second notch 56BCT2 is formed at one end in the longitudinal direction of the reflection plate 56 and opens in the direction toward the pressure roller. The third notch 56BCT3 is formed at the other end opposite to the one end in the longitudinal direction of the reflecting plate 56, and opens in the direction toward the pressure roller PR. The first notch 56BCT1 is disposed between the second notch 56BCT2 and the third notch 56BCT3.

  As shown in FIG. 10, the downstream extension 56 </ b> B of the reflection plate 56 has an edge EDG that forms a first notch 56 </ b> BCT <b> 1. The edge EDG includes a first notch edge 56EDG1, a second notch edge 56EDG2, a third notch edge 56EDG3, a fourth notch edge 56EDG4, and a fifth notch edge 56EDG5.

  The first notch 56ECT1 opens between the first edge 56BEG1 and the second edge 56BEG2, the second notch edge 56EDG2 opens between the second edge 56BEG2 and the third edge 56BEG3, and the third The notch edge 56EDG3 is opened between the first edge 56BEG1 and the fourth edge 56BEG4.

  The first notch edge 56EDG1 and the second notch edge 56EDG2 form an opening that opens in the direction toward the pressure roller PR between the first notch edge 56EDG1 and the second notch edge 56EDG2. The distance between the first notch edge 56EDG1 and the second notch edge 56EDG2 increases as the pressure roller PR is approached.

  The third notch edge 56EDG3 extends from the end of the second notch edge 56EDG2 farthest from the pressure roller PR and extends away from the pressure roller PR. The fourth notch edge 56EDG3 extends from the end of the first notch edge 56EDG1 farthest from the pressure roller PR and extends away from the pressure roller PR. The distance between the third notch edge 56EDG3 and the fourth notch edge 56EDG4 increases as the distance from the pressure roller PR increases.

  With the above configuration, the first notch edge 56EDG1, the second notch edge 56EDG2, the third notch edge 56EDG3, and the fourth notch edge 56EDG4 form a constricted shape as shown in FIG. The fifth notch edge EDG5 connects the third notch edge 56EDG3 and the fourth notch edge 56EDG4.

  As shown in FIG. 10, the downstream extending portion 56B of the reflector 56 has the same configuration as the first notch 56BCT1 with respect to the second notch 56BCT2 and the third notch 56BCT3. Therefore, the second notch 56BCT2 and the third notch 56BCT3 The detailed description about is omitted.

<Assembly process of structure ASSY>
Next, the assembly process of the structure ASSY will be described.

  First, the stay 53 is assembled to the heat insulating material 55.

  Next, a process for assembling the nip plate 52 to the heat insulating material 55 will be described. The operator brings the nip plate 52 close to the heat insulating material 55 while keeping the posture of the nip plate 52 and the posture of the heat insulating material 55 as shown in FIG.

  When the nip plate 52 and the heat insulating material 55 approach each other, first, the edge 52BEG of the downstream extension portion 52B of the nip plate 52 comes into contact with the inclined surface 55BGT of the guide 55BG of the downstream wall 55B of the heat insulating material 55. Then, the edge 52BEG of the downstream extension portion 52B is guided in the direction away from the pressure roller PR while receiving the downstream force in the transport direction (FD) from the inclined surface 55BGT of the guide 55BG (guide process).

  When the nip plate 52 and the heat insulating material 55 come closer, the base 55BBB of the protrusion 55BB of the heat insulating material 55 (downstream wall 55B) fits into the notch 52BCT of the nip plate 52 (downstream extending portion 52B) (a fitting process).

  More specifically, at this time, the first protrusion 55BB1 included in the protrusion 55BB is press-fitted between the first notch edge 52EDG1 and the second notch edge 52EDG2. Then, the notch edge 52EDG is elastically deformed, but the distance between the first notch edge 52EDG1 and the second notch edge 52EDG2 is slightly increased. Further, when the first protrusion 55BB1 is pushed between the first notch edge 52EDG1 and the second notch edge 52EDG2, the protrusion 55BB becomes the third notch edge 52EDG3, the fourth notch edge 52EDG4, and the fifth notch edge 52EDG5. It enters the enclosed triangular space and is fixed. Similarly, each of the second protrusion 55BB2 and the third protrusion 55BB3 fits into the notch 52BCT2 and the notch 52BCT3.

  When the protrusion 55BB of the heat insulating material 55 fits into the notch 52BCT of the nip plate 52, it contacts the positioning surface 55BGV of the guide 55BG of the heat insulating material 55 (downstream wall 55B), and the position of the nip plate 52 in the transport direction (FD) is restricted. The

  When the protrusion 55BB of the downstream wall 55B of the heat insulating material 55 fits into the notch 52BCT of the nip plate 52, the protrusion 55AB of the upstream wall 55A of the heat insulating material 55 is similarly fitted and fixed to the notch 52ACT of the nip plate 52. As described above, the nip plate 52 is fixed to the heat insulating material 55.

  Next, a process for assembling the reflection plate 56 to the heat insulating material 55 will be described. The operator brings the reflecting plate 56 close to the heat insulating material 55 while keeping the posture of the reflecting plate 56 and the posture of the heat insulating material 55 as shown in FIG.

  When the reflecting plate 56 and the heat insulating material 55 come closer, first, the edge 56AEG of the upstream extending portion 56A of the reflecting plate 56 contacts the inclined surface 55AGT of the guide 55AG of the upstream wall 55A of the heat insulating material 55. Then, the edge 56AEG of the upstream extending portion 56A is guided in a direction approaching the pressure roller PR while receiving an upstream force in the transport direction (FD) from the inclined surface 55AGT of the guide 55AG (guide process).

  When the reflecting plate 56 and the heat insulating material 55 are further brought closer, the base 55ABB of the protrusion 55AB of the heat insulating material 55 (upstream wall 55A) is fitted into the notch 56ACT of the reflecting plate 56 (upstream extending portion 56A) (a fitting process).

  More specifically, at this time, the first protrusion 55AB1 having the protrusion 55BA is press-fitted between the first notch edge 56EDG1 and the second notch edge 56EDG2. Then, the notch edge 56EDG is elastically deformed, but the distance between the first notch edge 56EDG1 and the second notch edge 56EDG2 is slightly increased. Further, when the first protrusion 55AB1 is pushed between the first notch edge 56EDG1 and the second notch edge 56EDG2, the protrusion 55AB is moved into the third notch edge 56EDG3, the fourth notch edge 56EDG4, and the fifth notch edge 56EDG5. It enters the enclosed triangular space and is fixed. Similarly, each of the second protrusion 55AB2 and the third protrusion 55AB3 fits into the notch 56ACT2 and the notch 56ACT3.

  When the protrusion 55AB of the heat insulating material 55 fits into the notch 56ACT of the reflecting plate 56, it contacts the positioning surface 55AGV of the guide 55AG of the heat insulating material 55 (upstream wall 55A), and the position of the reflecting plate 56 in the transport direction (FD) is restricted. The

  When the projection 55BB of the upstream wall 55A fits into the notch 56ACT of the reflector 56, the projection 55BB of the downstream wall 55B of the heat insulating material 55 is similarly fitted and fixed to the notch 56BCT of the reflector 56. By the above, the reflecting plate 56 is fixed to the heat insulating material 55, and the assembly of the structure ASSY is completed.

  As shown in FIG. 4, the edge 56BEG facing the pressure roller PR of the downstream extension portion 56B of the reflecting plate 56 is covered by a cover portion 52BCV (52BCV1, cover portion 52BCV2) indicated by a broken line of the downstream extension portion 52B of the nip plate 52. , Cover portions 52BCV3 and 52BCV4). A part of the cover part 52BCV1, the cover part 52BCV2, a part of the cover part 52BCV3, and a part of the cover part 52BCV4 are exposed on the inner peripheral surface 51IN of the endless belt 51. Further, the cover part 52BCV1, the cover part 52BCV2, a part of the cover part 52BCV3, and a part of the cover part 52BCV4 are directly opposed to the inner peripheral surface 51IN of the endless belt 51. However, the side guide SG1 is interposed between the other part different from the above part of the cover part 52BCV3 and the inner peripheral surface 51IN of the endless belt 51, and the other part different from the above part of the cover part 52BCV4 and the endless belt. A side guide SG2 is interposed between the inner peripheral surface 51IN of 51.

  As shown in FIG. 5, the edge 52AEG facing the direction away from the pressure roller PR of the upstream extension portion 52A of the nip plate 52 is a cover portion 52BCV (52ACV1, 52ACV1, shown by the broken line of the upstream extension portion 56A of the reflection plate 56. Cover portion 52ACV2, cover portion 52ACV3, and cover portion 52ACV4). A part of the cover part 52ACV1, the cover part 52ACV2, a part of the cover part 52ACV3, and a part of the cover part 52ACV4 are exposed on the inner peripheral surface 51IN of the endless belt 51. Further, the cover part 52ACV1, the cover part 52ACV2, a part of the cover part 52ACV3, and a part of the cover part 52ACV4 are directly opposed to the inner peripheral surface 51IN of the endless belt 51. However, the side guide SG1 is interposed between the other part different from the part of the cover part ACV3 and the inner peripheral surface 51IN of the endless belt 51, and the other part different from the part of the cover part ACV3 and the endless belt. A side guide SG2 is interposed between the inner peripheral surface 51IN of 51.

<Outline of operation of fixing device 5>
Next, an outline of the fixing operation of the fixing device 5 will be described. The fixing operation of the fixing device 5 occurs during the printing operation.

  The nip plate 52 is pressed against the pressure roller PR via the stay 53 and the heat insulating material 55 by a biasing force of a spring (not shown). When the nip plate 52 is pressed in this way, the nip plate 52 and the pressure roller PR sandwich the endless belt 51 between the nip plate 52 and the pressure roller PR, and the endless belt 51 and the pressure roller PR A fixing nip NIP is formed between the two. The operation for forming the fixing nip NIP may be executed during the printing operation as described above, but the fixing nip NIP may be always maintained when the printing operation is not performed.

  A motor (not shown) drives the pressure roller PR, and the pressure roller PR rotates around the rotation axis AXIS in the counterclockwise direction in FIG. 2 as shown in FIG. By rotating the pressure roller PR in this way, the endless belt 51 rotates clockwise in FIG. 2 as shown in FIG.

  The heater HTR generates radiant heat when electric power is supplied to the heater HTR. The reflector 56 reflects the radiant heat from the heater HTR toward the inner peripheral surface 51IN of the endless belt 51. The endless belt 51 is heated and stored by the radiant heat reflected from the reflecting plate 56. The endless belt 51 carries the stored heat to the fixing nip NIP by rotating.

The endless belt 51 and the pressure roller PR that have accumulated heat sandwich the paper P at the fixing nip NIP, thereby applying heat and pressure to the developer image on the paper P and thermally fixing the developer image on the paper P.

  Next, effects obtained by the above-described configuration will be described.

  Since the edge 56BEDG of the downstream extension portion 56B of the reflection plate 56 is covered with the cover portion 52BCV1, the cover portion 52BCV2, the cover portion, and the 52BCV3 of the downstream extension portion 52B of the nip plate 52, the inner peripheral surface of the endless belt 51 It is possible to prevent the endless belt 51 from being damaged due to strong contact between 51IN and the edge 56BEDG.

  Since the downstream extending portion 56B of the reflector 56 has a notch 56BCT that opens in the direction toward the pressure roller PR, and the downstream wall 55B of the heat insulating material 55 has a projection 56BB for fixing the notch 56BCT. It becomes easy to attach the reflecting plate 56 to the heat insulating material 55.

  Since the upstream extension portion 56A of the reflector 56 has a notch 56ACT that opens in the direction toward the pressure roller PR, and the upstream wall 55A of the heat insulating material 55 has a protrusion 56AA for fixing the notch 56ACT. It becomes easy to attach the reflecting plate 56 to the heat insulating material 55.

  The upstream extension 52A of the nip plate 52 has a notch 52ACT that opens in a direction away from the pressure roller PR, and the upstream wall 55A of the heat insulating material 55 has a protrusion 56AB for fixing the notch 56ACT. It becomes easy to assemble the nip plate 52 to the heat insulating material 55.

  The downstream extension 52B of the nip plate 52 has a notch 52BCT that opens in a direction away from the pressure roller PR, and the downstream wall 55B of the heat insulating material 55 has a protrusion 56BB for fixing the notch 56BCT. It becomes easy to assemble the nip plate 52 to the heat insulating material 55.

  Since the heat insulating material 55 has the guide 55AG, assembly and positioning of the nip plate 52 with respect to the heat insulating material 55 are facilitated.

  Since the heat insulating material 55 has the guide 55BG, assembly and positioning of the reflector 56 with respect to the heat insulating material 55 are facilitated.

<Modification>
In the above embodiment, the heat insulating material 55 is shown as an example of the support member. However, the support member may be a member having a higher thermal conductivity than the stay 53 or the like.

  In the above embodiment, the heat insulating material 55 is shown as an example of the support member, but the support member may be the stay 53.

  In the above embodiment, the guide 55AG has been disclosed as a configuration for assembling and positioning the reflector 56 to the heat insulating material 55, but the guide 55AG may not be provided.

  In the above embodiment, the guide 55BG is disclosed for assembling and positioning the nip plate 52 to the heat insulating material 55, but the guide 55BG may be omitted.

  In the above embodiment, the reflection portion 56C of the reflection plate 56 has a substantially flat plate shape, but a part of the reflection portion 56C may be uneven. For example, a part of the reflection portion 56C may have a shape that is recessed in a direction away from the heater HTR when viewed from the longitudinal direction of the reflection plate 56. And the other part adjacent to the said part of 56 C of reflection parts may be a flange shape (cap shape of a hat), when it sees from the longitudinal direction of the reflecting plate 56. FIG.

  In the above embodiment, the nip plate 52 is shown as an example of the nip member. However, a block-like member or a pad-like member may be adopted as the nip member.

  In the above embodiment, the nip plate 52 is in contact with the inner peripheral surface 51IN of the endless belt 51. However, a sliding sheet or the like may be interposed between the nip plate 52 and the endless belt 51.

  In the above embodiment, the reflection plate 56 is disposed between the heater HTR and the nip plate 52, and the radiant heat from the heater HTR is reflected in the direction away from the nip plate 52. It is good also as a structure which is arrange | positioned between 52 and the reflecting plate 56, and the reflecting plate 56 reflects the radiant heat from heater HTR toward the nip plate 52. FIG.

1 Printer 5 Fixing Device 51 Endless Belt 52 Nip Plate 53 Stay 56 Reflecting Plate 55 Heat Insulating Material
HRT heater
PR Pressure roller 55AG guide 55BG guide

Claims (12)

Endless belt,
A nip plate that contacts the inner peripheral surface of the endless belt;
A backup member that forms a nip with the endless belt by sandwiching the endless belt with the nip plate;
A heater that generates heat inside the endless belt;
A fixing device that reflects the heat from the heater, and transports the recording sheet in a predetermined transport direction in the nip to fix the developer image on the recording sheet,
The reflecting plate includes a reflecting portion having a reflecting surface that reflects heat from the heater, an upstream extending portion that extends from the upstream end of the reflecting portion in the transport direction and extends toward the backup member, and the reflecting member. A downstream extension portion extending from the downstream end in the transport direction of the portion and extending toward the backup member, and having a tip.
The nip plate extends from the upstream end of the central portion in the transport direction and extends away from the backup member, and has an upstream extension having a tip. The central portion sandwiches the endless belt with the backup member. A downstream extension portion extending from the downstream end of the central portion in the transport direction and extending away from the backup member,
The upstream extension portion of the reflector is disposed upstream in the transport direction with respect to the tip of the upstream extension surface of the nip plate and covers at least a part of the tip of the upstream extension surface of the nip plate. Having an upstream cover,
The downstream extension part of the nip plate is arranged downstream in the transport direction with respect to the tip of the downstream extension part of the reflector and covers a tip of the downstream extension of the reflector. A fixing device. A support member that supports the reflector;
The support member is
An upstream wall having an upstream protrusion projecting upstream in the transport direction; and a downstream wall having a downstream protrusion disposed downstream of the upstream wall and projecting downstream in the transport direction;
The upstream extension of the reflector has an upstream notch that opens toward the backup member and engages the upstream projection of the upstream wall;
2. The fixing device according to claim 1, wherein the downstream extension portion of the reflection plate has a downstream cutout portion that opens toward the backup member and engages with the downstream protrusion of the downstream wall. . The upstream extension portion of the nip plate has an upstream notch that opens in a direction away from the backup member and engages with the upstream protrusion of the upstream wall;
The said downstream extension part of the said nip plate has a downstream notch part which opens in the direction away from the said backup member, and engages with the said downstream protrusion of the said downstream wall, It is characterized by the above-mentioned. Fixing device. A support member for supporting the nip plate;
The support member has an upstream wall having an upstream protrusion protruding upstream in the transport direction, and a downstream wall disposed downstream of the upstream wall and having a downstream protrusion protruding downstream in the transport direction,
The upstream extension of the nip plate has an upstream cutout that opens in a direction away from the backup member and engages with the upstream protrusion of the upstream wall;
The said downstream extension part of the said nip plate has a downstream notch part which opens in the direction away from the said backup member, and engages with the said downstream protrusion of the said downstream wall, It is characterized by the above-mentioned. Fixing device.   The upstream wall of the support member is disposed between the tip of the upstream extension portion of the nip plate and the reflection portion of the reflection plate, and downstream of the upstream extension portion of the reflection plate in the transport direction. 5. The fixing device according to claim 2, further comprising an upstream projecting wall projecting toward a facing downstream surface. 6.   The downstream wall of the support member extends to an upstream surface facing the upstream of the downstream extension portion of the nip plate between the tip of the downstream extension portion of the reflector and the central portion of the nip plate. The fixing device according to claim 2, further comprising a downstream projecting wall projecting toward the head. Endless belt,
A nip member that contacts the inner peripheral surface of the endless belt;
A backup member that forms a nip with the endless belt by sandwiching the endless belt with the nip member;
A heater that generates heat inside the endless belt;
A fixing device that reflects the heat from the heater, and transports the recording sheet in a predetermined transport direction in the nip to fix the developer image on the recording sheet,
The reflecting plate includes a reflecting portion having a reflecting surface that reflects heat from the heater, and a downstream extending portion having a tip extending from a downstream end in the transport direction of the reflecting portion toward the backup member. Have
The nip member includes a central portion that sandwiches the endless belt with the backup member, and a downstream extending portion that extends from the downstream end of the central portion in the transport direction and extends away from the backup member. Have
The downstream extension part of the nip member is arranged downstream in the transport direction with respect to the tip of the downstream extension part of the reflector, and covers a tip of the downstream extension part of the reflector. A fixing device. A support member that supports the reflector;
The support member has a downstream wall having a downstream protrusion protruding downstream in the transport direction,
The fixing device according to claim 7, wherein the downstream extension portion of the reflection plate has a downstream cutout portion that opens toward the backup member and engages with the downstream protrusion of the downstream wall. .   The said downstream extension part of the said nip member is opened in the direction away from the said backup member, and has a downstream notch part engaged with the said downstream protrusion of the said downstream wall, It is characterized by the above-mentioned. Fixing device. A support member for supporting the nip member;
The support member has a downstream wall having a downstream protrusion protruding downstream in the transport direction,
The said downstream extension part of the said nip member has a downstream notch part which opens in the direction away from the said backup member, and engages with the said downstream protrusion of the said downstream wall, It is characterized by the above-mentioned. Fixing device.   The downstream wall of the support member is between the tip of the downstream extension portion of the reflector and the central portion of the nip member, toward an upstream surface facing the upstream of the downstream extension portion of the nip member. The fixing device according to claim 8, further comprising a downstream projecting wall projecting toward the head.   The said reflecting plate is arrange | positioned between the said nip member and the said heater, and reflects the heat | fever from the said heater toward the internal peripheral surface of the said endless belt, Any one of the Claims 1-11 characterized by the above-mentioned. The fixing device according to claim 1.