JP4992988B2 - Fixing device - Google Patents

Description

  The present invention relates to a fixing device that thermally fixes a developer image transferred to a recording sheet.

  As a fixing device used in an electrophotographic image forming apparatus, a nip plate that forms a nip portion between a cylindrical fixing film, a heater disposed in the fixing film, and a pressure roller via the fixing film (For example, refer to Patent Document 1). In this fixing device, the developer image on the paper is thermally fixed while conveying the paper (recording sheet) between the fixing film supported by the nip plate and the pressure roller (nip portion).

JP 2008-233886 A

  By the way, in the fixing device described above, the curl amount (the degree to which the paper is rounded about the axis along the paper width direction due to fixing) differs depending on the type of paper such as plain paper or thick paper. Since the discharge direction of the paper discharged from the apparatus changes, it is necessary to adjust the discharge direction of the paper. In addition, normal discharge that is sent from the fixing device to a discharge tray on the upper surface of the image forming apparatus, straight discharge that discharges paper onto the rear cover from the opening formed in the rear wall of the image forming apparatus by opening the rear cover, Even when executing the above, it has been desired to adjust the paper discharge direction.

  SUMMARY An advantage of some aspects of the invention is that it provides a fixing device capable of adjusting the discharge direction of a sheet (recording sheet).

The present invention that solves the above-described problems is provided with a cylindrical fixing film, a heating element disposed inside the fixing film, and a sliding contact with an inner surface of the fixing film, and receives radiant heat from the heating element. A backup member that is elastically deformable and that is elastically deformed and sandwiches the fixing film between the nip member and forms a nip portion with the fixing film, and supports the backup member to the first support member, the second support member supporting the nip member, a fixing device provided with a rotating around a rotation axis along the axial direction of the second supporting member and the fixing film And a third support member supported by the first support member so that the backup member and the nip member are movable in a facing direction. , The nip member, with the rotation of the second support member pivots on the first posture and the second posture about the pivot axis, the discharge direction of the recording sheet from the nip It is configured to be switchable .

  According to the present invention, since the discharge direction of the recording sheet discharged along the nip member is changed by rotating the nip member and changing the posture of the nip member, the discharge direction of the recording sheet can be adjusted. .

  According to the present invention, the recording sheet discharge direction can be adjusted.

1 is a diagram illustrating a schematic configuration of a laser printer including a fixing device according to an embodiment of the present invention. 1 is a diagram illustrating a schematic configuration of a fixing device according to an embodiment of the present invention. It is a perspective view of a halogen lamp, a nip plate, a reflecting plate, and a stay. It is the figure which looked at the nip plate, the reflecting plate, and the stay from the conveyance direction. They are the perspective view (a) which looked at the guide member from the upper side, the perspective view (b) which looked at the guide member which attached the stay from the lower side, and the bottom view (c). FIG. 6 is a side view of the fixing device viewed from the left side when the nip plate is in a first posture. It is a side view which shows the state which cancelled | released nip pressure, when the nip plate is a 1st attitude | position. It is a side view which shows the state which rotated the nip board to the 2nd attitude | position. It is a side view which shows the state which returned nip pressure when a nip board is a 2nd attitude | position. 4A and 4B are explanatory diagrams illustrating a relationship between a nip plate and a pressure roller when changing a paper discharge direction. It is explanatory drawing (a), (b) which shows the form which comprised the lower surface of the nip board pressed by a pressure roller so that it might become a different curvature in each attitude | position.

  Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. In the following description, the schematic configuration of the laser printer 1 (image forming apparatus) including the fixing device 100 according to the embodiment of the present invention will be described first, and then the detailed configuration of the fixing device 100 will be described.

<Schematic configuration of laser printer>
As shown in FIG. 1, the laser printer 1 includes a main body housing 2 in which a paper sheet 3 as an example of a recording sheet is fed, an exposure device 4, and a toner image (developer) on the paper P. And the fixing device 100 for thermally fixing the toner image on the paper P.

  In the following description, the direction will be described with reference to the user who uses the laser printer. That is, the right side in FIG. 1 is “front”, the left side is “rear”, the front side is “left”, and the back side is “right”. Also, the vertical direction in FIG.

  The paper feed unit 3 is provided in the lower part of the main body housing 2, and includes a paper feed tray 31 that accommodates the paper P, a paper pressing plate 32 that lifts the front side of the paper P, a paper feed roller 33, and a paper feed pad 34. And paper dust removing rollers 35 and 36 and a registration roller 37 are mainly provided. The paper P in the paper feed tray 31 is brought close to the paper feed roller 33 by the paper pressing plate 32 and separated one by one by the paper feed roller 33 and the paper feed pad 34, and the paper dust removing rollers 35, 36 and the registration roller 37. Then, it is conveyed toward the process cartridge 5.

  The exposure apparatus 4 is arranged at the upper part in the main body housing 2 and mainly includes a laser light emitting unit (not shown), a polygon mirror 41 that is rotationally driven, lenses 42 and 43, and reflecting mirrors 44, 45, and 46. In preparation. In the exposure apparatus 4, the laser light (see the chain line) based on the image data emitted from the laser light emitting part is reflected or passed through the polygon mirror 41, the lens 42, the reflecting mirrors 44 and 45, the lens 43 and the reflecting mirror 46 in this order. The surface of the photosensitive drum 61 is scanned at high speed.

  The process cartridge 5 is disposed below the exposure apparatus 4 and is detachably mounted on the main body housing 2 through an opening formed when the front cover 21 provided on the main body housing 2 is opened. Yes. The process cartridge 5 includes a drum unit 6 and a developing unit 7.

  The drum unit 6 mainly includes a photosensitive drum 61, a charger 62, and a transfer roller 63. The developing unit 7 is configured to be detachably attached to the drum unit 6, and includes a developing roller 71, a supply roller 72, a layer thickness regulating blade 73, and a toner that contains toner (developer). The housing part 74 is mainly provided.

  In the process cartridge 5, the surface of the photosensitive drum 61 is uniformly charged by the charger 62 and then exposed by high-speed scanning of the laser light from the exposure device 4, whereby image data is transferred onto the photosensitive drum 61. An electrostatic latent image based on is formed. Further, the toner in the toner container 74 is supplied to the developing roller 71 via the supply roller 72 and enters between the developing roller 71 and the layer thickness regulating blade 73 to form a thin layer of a certain thickness on the developing roller 71. It is carried on.

  The toner carried on the developing roller 71 is supplied from the developing roller 71 to the electrostatic latent image formed on the photosensitive drum 61. As a result, the electrostatic latent image is visualized and a toner image is formed on the photosensitive drum 61. Thereafter, the paper P is conveyed between the photosensitive drum 61 and the transfer roller 63, whereby the toner image on the photosensitive drum 61 is transferred onto the paper P.

  The fixing device 100 is provided behind the process cartridge 5. The toner image (toner) transferred onto the paper P is thermally fixed onto the paper P by passing through the fixing device 100. The paper P on which the toner image is thermally fixed is discharged onto the paper discharge tray 22 by the transport rollers 23 and 24.

<Detailed configuration of fixing device>
As shown in FIG. 2, the fixing device 100 includes a fixing film 110, a halogen lamp 120 as an example of a heating element, a nip plate 130 as an example of a nip member, a reflection plate 140, and an example of a backup member. A pressure roller 150 and a stay 160 are provided.

  The fixing film 110 is an endless (cylindrical) film having heat resistance and flexibility, and both ends thereof are guided to rotate by guide members 170 described later.

  The halogen lamp 120 is a known heating element that heats the toner on the paper P by heating the nip plate 130 and the fixing film 110. Inside the fixing film 110, a predetermined amount of heat is supplied from the inner surfaces of the fixing film 110 and the nip plate 130. They are arranged at intervals.

  The nip plate 130 is a plate-like member that receives radiant heat from the halogen lamp 120, and is disposed so as to be in sliding contact with the inner surface of the cylindrical fixing film 110. The nip plate 130 transmits the radiant heat received from the halogen lamp 120 to the toner on the paper P through the fixing film 110.

  The nip plate 130 has a thermal conductivity higher than that of a steel stay 160, which will be described later. For example, the nip plate 130 is formed by bending an aluminum plate or the like into a substantially U shape in sectional view. More specifically, the nip plate 130 is bent toward the base portion 131 extending in the front-rear direction (the conveyance direction of the paper P) and upward (the direction from the pressure roller 150 toward the nip plate 130) in a cross-sectional view. The bent portion 132 is mainly included.

A lower surface 131A (surface on the pressure roller 150 side) of the base portion 131 is formed in a flat shape (0 curvature).
Note that the upper surface of the base portion 131 may be painted black or provided with a heat absorbing member. According to this, the radiant heat from the halogen lamp 120 can be efficiently absorbed.

  As shown in FIG. 3, the nip plate 130 further includes an insertion portion 133 that extends in a flat plate shape from the right end portion of the base portion 131, and an engagement portion 134 that is formed at the left end portion of the base portion 131. The engaging portion 134 is formed in a U shape in a side view, and an engaging hole 134B is provided in a side wall portion 134A formed by bending upward.

  As shown in FIG. 2, the reflecting plate 140 reflects the radiant heat from the halogen lamp 120 (radiant heat radiated mainly in the front-rear direction and the upward direction) toward the nip plate 130 (the inner surface of the base portion 131). It is a member and is arranged at a predetermined interval from the halogen lamp 120 so as to surround the halogen lamp 120 inside the fixing film 110.

  By collecting the radiant heat from the halogen lamp 120 to the nip plate 130 with such a reflector 140, the radiant heat from the halogen lamp 120 can be used efficiently, and the nip plate 130 and the fixing film 110 can be heated quickly. Can do.

  The reflection plate 140 is formed by curving an aluminum plate or the like in a substantially U shape in cross section, for example, having a high infrared and far infrared reflectance. More specifically, the reflecting plate 140 mainly includes a reflecting portion 141 having a curved shape (substantially U-shaped in cross section) and a flange portion 142 extending from both ends of the reflecting portion 141 along the outer side in the front-rear direction. . In order to increase the thermal reflectance, the reflection plate 140 may be formed using a mirror-finished aluminum plate or the like.

  As shown in FIG. 3, a total of four flange-like locking portions 143 are formed at both ends of the reflection plate 140 in the left-right direction (the width direction of the paper P) (only three are shown). The locking portion 143 is located above the flange portion 142. As shown in FIG. 4, when the nip plate 130, the reflecting plate 140, and the stay 160 are assembled, a plurality of contact portions 163 of the stay 160 described later are provided. It arrange | positions so that it may pinch | interpose (adjacent to the outermost contact part 163A in the left-right direction).

  As a result, even if the reflection plate 140 tries to move left and right due to vibrations when the fixing device 100 is driven, the position of the reflection plate 140 in the left-right direction is restricted by the locking portion 143 coming into contact with the contact portion 163A. The As a result, it is possible to suppress the displacement of the reflecting plate 140 in the left-right direction.

  As shown in FIG. 2, the pressure roller 150 is an elastically deformable member and is disposed below the nip plate 130. The pressure roller 150 forms a nip portion with the fixing film 110 by sandwiching the fixing film 110 with the nip plate 130 in an elastically deformed state.

  The pressure roller 150 is configured to be driven to rotate by a driving force transmitted from a motor (not shown) provided in the main body housing 2, and to rotate with the fixing film 110 (or paper P). The fixing film 110 is driven and rotated by the frictional force.

  The sheet P on which the toner image is transferred is conveyed between the pressure roller 150 and the heated fixing film 110 (nip portion), whereby the toner image (toner) is thermally fixed.

  The stay 160 is a member that secures the rigidity of the nip plate 130 by supporting both end portions 131B of the nip plate 130 (base portion 131) in the front-rear direction via the flange portion 142 of the reflection plate 140. The stay 160 has a shape (substantially U shape in cross section) along the outer surface shape of the reflecting plate 140 (reflecting portion 141) and is disposed so as to cover the reflecting plate 140. Such a stay 160 has relatively high rigidity, for example, is formed by bending a steel plate or the like into a substantially U shape in cross-sectional view.

  At the lower ends of the front wall 161 and the rear wall 162 of the stay 160, as shown in FIG. 3, a plurality of contact portions 163 formed in a substantially comb shape are provided.

  Further, a substantially L-shaped locking portion 165 extending downward and further toward the left is provided at the right end portions of the front wall 161 and the rear wall 162 of the stay 160. Further, a holding portion 167 is provided at the left end of the stay 160 and extends leftward from the upper wall 166 and is bent into a substantially U shape in a side view. Engagement bosses 167B (only one is shown) projecting inward are provided on the inner surfaces of the side wall portions 167A of the holding portion 167.

  As shown in FIGS. 2 and 3, a total of four abutting bosses 168 projecting inward are provided at both ends in the left-right direction of the inner surfaces of the front wall 161 and the rear wall 162 of the stay 160. The abutting boss 168 abuts on the reflecting plate 140 (reflecting portion 141) in the front-rear direction. As a result, even if the reflection plate 140 tries to move back and forth due to vibrations when the fixing device 100 is driven, the position of the reflection plate 140 in the front-rear direction is restricted by contacting the contact boss 168. As a result, it is possible to suppress the displacement of the reflector plate 140 in the front-rear direction.

  Further, supported portions 169 projecting outward in the left-right direction are formed at the upper portions of the left and right ends of the stay 160, and the supported portions 169 are supported by guide members 170 described later.

  When the reflecting plate 140 and the nip plate 130 are assembled to the stay 160 described above, the reflecting plate 140 is first attached to the stay 160 so as to be fitted. Since the abutting boss 168 is provided on the inner surfaces of the front wall 161 and the rear wall 162 of the stay 160, the reflecting plate 140 is temporarily held by the stay 160 when the abutting boss 168 contacts the reflecting plate 140. The

  Thereafter, as shown in FIG. 4, the insertion portion 133 of the nip plate 130 is inserted between the locking portions 165 of the stay 160 to engage the base portion 131 (both end portions 131B) with the locking portions 165, and then Then, the engaging portion 134 (engaging hole 134B) of the nip plate 130 and the holding portion 167 (engaging boss 167B) of the stay 160 are engaged.

  Thereby, the both ends 131 </ b> B of the base portion 131 are supported by the locking portion 165 and the engaging portion 134 is held by the holding portion 167, so that the nip plate 130 is held by the stay 160. In addition, the reflecting plate 140 is held by the stay 160 in a state where the flange portion 142 is sandwiched between the nip plate 130 and the stay 160.

  As a result, even if the reflection plate 140 tries to move up and down due to vibrations when the fixing device 100 is driven, the flange portion 142 is sandwiched between the nip plate 130 and the stay 160 so that the reflection plate 140 is moved in the vertical direction. The position of is regulated. As a result, it is possible to suppress the positional deviation of the reflecting plate 140 in the vertical direction, and to fix the position of the reflecting plate 140 with respect to the nip plate 130.

  The stay 160 that holds the nip plate 130 and the reflection plate 140 and the halogen lamp 120 are directly fixed to the guide member 170 shown in FIG. That is, the guide member 170 integrally supports the nip plate 130, the reflection plate 140, the stay 160, and the halogen lamp 120.

  The guide member 170 is formed in an approximately cylindrical shape with an insulating material such as a resin, and is disposed one by one on both ends of the fixing film 110 to mainly move the fixing film 110 in the left-right direction (axial direction). It is regulated. Specifically, the guide member 170 includes a restriction surface 171 for restricting the movement of the fixing film 110 in the left-right direction, a suppressing portion 172 for suppressing deformation of the fixing film 110 inward in the radial direction, and both end portions of the stay 160. Is mainly provided with a holding recess 173.

  The suppressing portion 172 is a rib that protrudes inward in the left-right direction from the restriction surface 171 and is formed in a C shape with the opening facing downward. The suppressing portion 172 suppresses deformation inward in the radial direction by entering the fixing film 110. Further, the opening facing the lower side of the suppressing portion 172 serves as an escape portion for inserting the stay 160 into the holding recess 173.

  The holding recess 173 is a groove that opens downward and penetrates inward in the left-right direction. Of the walls that form the holding recess 173, the pair of side walls 174 that face each other in the front-rear direction are shown in FIGS. ), A pair of engagement protrusions 174A are formed. Each engagement protrusion 174A is formed so as to protrude inward from a position away from the bottom surface 173A of the holding recess 173 (see FIG. 5A).

  5B, when the supported portion 169 of the stay 160 is inserted between the bottom surface 173A of the holding recess 173 and the pair of engaging protrusions 174A, the supported portion 169 moves in the vertical direction. Is regulated by the bottom surface 173A of the holding recess 173 and the pair of engaging protrusions 174A. Thereby, it is possible to suppress the positional deviation of the stay 160 in the vertical direction with respect to the guide member 170.

  Further, the edge 160A on the outer side in the left-right direction of the stay 160 is in contact with the inner surface 174B in the left-right direction of the pair of engaging protrusions 174A. As a result, even if the stay 160 tries to move left and right due to vibration or the like when the fixing device 100 is driven, the position of the stay 160 in the left-right direction is restricted by the engagement protrusion 174A coming into contact with the stay 160. As a result, the displacement of the stay 160 in the left-right direction with respect to the guide member 170 can be suppressed.

  Further, the stay 160 is sandwiched between the pair of side walls 174 of the holding recess 173 in the front-rear direction, so that the positional deviation in the front-rear direction is suppressed. As described above, the stay 160 is supported by the guide member 170, whereby the nip plate 130 and the reflection plate 140 are integrally supported by the guide member 170 via the stay 160.

  Further, a fixing portion 175 for fixing the halogen lamp 120 is formed on the outer side of the guide member 170 in the left-right direction so as to protrude outward in the left-right direction. A mounting hole 175A for screwing a bolt B (see FIG. 6) is formed on the lower surface of the fixing portion 175. Then, as shown in FIG. 6, the plate-like terminal 121 at the end portion of the halogen lamp 120 is directly fixed to the lower surface of the fixing portion 175 with a bolt B. The terminal 121 is electrically connected to a power source (not shown) of the main body housing 2 of the laser printer 1 via a flexible wiring.

  A portion on the inner side in the left-right direction of the outer peripheral surface 170A of the guide member 170 is rotatably supported by a slide member 190 supported by the fixing frame 180 so as to be movable up and down. In other words, the nip plate 130 supported by the guide member 170 is rotatable about a rotation axis along the axial direction of the fixing film 110 (see FIG. 2).

  Further, an operation piece 176, a spring engagement portion 177, and an engagement piece 178 are provided on the outer side surface 170A of the guide member 170 on the outer side in the left-right direction so as to protrude radially outward.

  The operation piece 176 is a part that is gripped and rotated by the user, and extends rearward from the outer peripheral surface 170A of the guide member 170.

  The spring engaging portion 177 is provided on the front upper portion of the guide member 170, and can be engaged with each of the two recessed portions 191A formed in the leaf spring 191 provided on the slide member 190, and each recessed portion 191A. Is held in that position in the engaged state. Specifically, the two recesses 191 </ b> A are provided side by side in a substantially vertical direction (the circumferential direction of the guide member 170), and are formed to open toward the guide member 170.

  The engaging piece 178 is provided at the front lower portion of the guide member 170, and is disposed between the two restricting members 192 provided on the slide member 190 so as to be arranged substantially in the vertical direction (the circumferential direction of the guide member 170). The member 192 and the guide member 170 can be contacted in the circumferential direction. Specifically, the engaging piece 178 abuts on the upper regulating member 192 from the lower side when the spring engaging portion 177 is engaged with the upper concave portion 191A, and as shown in FIG. When engaged with the lower concave portion 191A, the lower regulating member 192 abuts from above.

  As a result, the nip plate 130 supported by the guide member 170 is appropriately rotated between the first posture shown in FIG. 6 and the second posture shown in FIG. 9 and is held in each posture. ing. That is, in this embodiment, the nip plate 130 is rotated between the first posture and the second posture by the guide member 170 and the slide member 190 that rotatably supports the guide member 170. An adjustment mechanism for adjusting the discharge direction of the paper P from the nip portion is configured.

  Further, as shown in FIG. 6, a support plate 210 is fixed to the upper surface of the slide member 190 so as to extend while being appropriately bent substantially rearward (cam portion 186 described later). Between the support plate 210 and the upper frame 181 fixed to the upper part of the fixing frame 180, there is a coil spring S that constantly urges the support plate 210 and the guide member 170 downward (on the pressure roller 150 side). Is provided. Thereby, a suitable nip pressure is applied between the nip plate 130 and the pressure roller 150 during printing control.

  A shaft support groove 182 that supports the pressure roller 150 via the bearing 200 and a support groove 183 that supports the slide member 190 movably up and down are formed on the left and right side walls of the fixing frame 180.

  Further, a release mechanism CM that releases the nip pressure by moving the nip plate 130 away from the pressure roller 150 is provided on the left and right side walls of the fixing frame 180. The release mechanism CM includes an operation lever 184, a rotation shaft 185, and a cam portion 186.

  One end of the operation lever 184 is integrally fixed to a rotating shaft 185 penetrating the left and right side walls of the fixing frame 180, and the rotating shaft 185 is rotatably supported by the fixing frame 180.

  The cam portion 186 is integrally fixed to the rotation shaft 185 so as to protrude radially outward from both left and right ends of the rotation shaft 185. Therefore, when the operating lever 184 is rotated and the left and right support plates 210 are pressed upward by the left and right cam portions 186, the left and right slide members 190 resist the urging force of the coil spring S as shown in FIG. Ascending, the nip plate 130 is separated from the pressure roller 150 and the nip pressure is released.

  In this state, when the user grasps the operation piece 176 and rotates the guide member 170 in the clockwise direction in the drawing, the nip plate 130 rotates from the first position to the second position as shown in FIG. To do. Thereafter, as shown in FIG. 9, when the operation lever 184 is returned to the original position, the cam portion 186 is detached from the left and right support plates 210, and the left and right slide members 190 are lowered by the urging force of the coil spring S. The nip plate 130 is pressed against the pressure roller 150 to generate a nip pressure.

  By the above operation, the nip plate 130 is rotated from the first posture shown in FIG. 10A to the second posture shown in FIG. Accordingly, the lower surface 131A of the nip plate 130 that is horizontal in the first posture is inclined with a predetermined inclination in the second posture. Therefore, the discharge direction of the paper P discharged in the direction along the lower surface 131A of the nip plate 130 is changed from the horizontal direction to the direction obliquely upward to the rear, and the discharge direction of the paper P is appropriately adjusted in these two directions. be able to. When the nip plate 130 is moved from the second posture to the first posture, the above-described operation may be performed in reverse.

According to the above, the following effects can be obtained in the present embodiment.
By rotating the nip plate 130 and changing the posture of the nip plate 130, the discharge direction of the paper P discharged along the lower surface 131A of the nip plate 130 changes, so the discharge direction of the paper P can be adjusted. .

  Since the release mechanism CM for releasing the nip pressure is provided, the nip plate 130 can be smoothly rotated.

In addition, this invention is not limited to the said embodiment, It can utilize with various forms so that it may illustrate below.
In the above-described embodiment, the form in which the curvature of the lower surface 131A of the nip plate 130 pressed by the pressure roller 150 does not change regardless of whether the posture is the first posture or the second posture is described. However, the present invention is not limited to this, and the curvature of the lower surface of the nip plate pressed by the pressure roller may be different in each posture.

  For example, as shown in FIGS. 11A and 11B, when the nip plate 230 is in the first posture (the posture of FIG. 11A) among the lower surfaces 231 of the nip plate 230, the pressure roller 150. The portion pressed by the pressure roller 150 (specifically, the portion PA1 on the downstream side in the transport direction) is pressed by the pressure roller 150 when the nip plate 230 assumes the second posture (the posture shown in FIG. 11B) (details). May be formed with a curvature different from the curvature of the part PA2) on the downstream side in the transport direction. According to this, the discharge direction of the paper P can be changed by the portions PA1 and PA2 having different curvatures, and the nip width can be changed to an appropriate width. Further, by changing the curvature of each part PA1, PA2 in each posture, it is possible to prevent the rotating nip plate 230 from biting into the pressure roller 150 more than necessary. Damage can be suppressed.

  In particular, as shown in FIGS. 11 (a) and 11 (b), when the nip plate 230 is rotated around the center of curvature C of one part PA2 of the parts PA1 and PA2 having different curvatures, the nip plate 230 Can be further prevented from entering the pressure roller 150 more than necessary.

  In the form shown in FIGS. 11A and 11B, the curvatures of the portions PA1 and PA2 on the downstream side in the transport direction in the portion pressed by the pressure roller 150 of the lower surface 231 of the nip plate 230 are different in each posture. However, the present invention is not limited to this. For example, the curvature of the entire portion pressed by the pressure roller on the lower surface of the nip plate may be configured to be different in each posture, or the curvature of the portion on the upstream side in the transport direction is configured to be different in each posture. It may be.

  In the above embodiment, the release mechanism CM for releasing the nip pressure is provided. However, the present invention is not limited to this, and the nip plate 130 is rotated without providing the release mechanism, that is, without releasing the nip pressure. Also good.

  In the above embodiment, the halogen lamp 120 and the nip plate 130 are integrally supported by the guide member 170. However, the present invention is not limited to this. For example, the halogen lamp is fixed to the main body housing, and the nip plate is used as the halogen lamp. May be relatively rotatable.

In the above-described embodiment, the reflecting plate 140 and the stay 160 are provided. However, the present invention is not limited to this, and the reflecting plate and the stay may be omitted.
In the embodiment, the halogen lamp 120 (halogen heater) is exemplified as the heating element. However, the present invention is not limited to this, and may be, for example, an infrared heater or a carbon heater.

In the embodiment, the plate-shaped nip plate 130 is exemplified as the nip member. However, the present invention is not limited to this, and a thick member that is not plate-shaped may be employed.
In the embodiment, the pressure roller 150 is exemplified as the backup member. However, the present invention is not limited to this, and may be, for example, a belt-like pressure member.

  In the above embodiment, the nip portion is formed by pressing the nip plate 130 against the pressure roller 150 (backup member). However, the present invention is not limited to this, and the backup member is pressed against the nip member. It is good also as a structure which forms a nip part. In this case, a mechanism for releasing the nip pressure by moving the backup member away from the nip member may be employed as the release mechanism.

  In the embodiment, the paper P such as plain paper or postcard is exemplified as the recording sheet, but the present invention is not limited to this, and may be, for example, an OHP sheet.

  In the above-described embodiment, the laser printer 1 is exemplified as the image forming apparatus including the fixing device of the present invention. However, the present invention is not limited to this. For example, an LED printer that performs exposure using LEDs may be used. It may be a copying machine or a multifunction machine. In the above-described embodiment, an image forming apparatus that forms a monochrome image is exemplified. However, the present invention is not limited to this, and an image forming apparatus that forms a color image may be used.

DESCRIPTION OF SYMBOLS 100 Fixing device 110 Fixing film 120 Halogen lamp 130 Nip plate 131A Lower surface 150 Pressure roller 170 Guide member CM release mechanism P Paper

Claims (4)

A cylindrical fixing film;
A heating element disposed inside the fixing film;
A nip member disposed so as to be in sliding contact with the inner surface of the fixing film and receiving radiant heat from the heating element;
A backup member that is elastically deformable and forms a nip portion with the fixing film by sandwiching the fixing film with the nip member in an elastically deformed state ;
A first support member for supporting the backup member;
A second support member that supports the nip member, and a fixing device comprising:
The second support member is supported so as to be rotatable around a rotation axis along the axial direction of the fixing film, and the backup member and the nip member are movable in a facing direction. A third support member supported by the one support member;
The nip member, with the rotation of the second support member pivots on the first posture and the second posture about the pivot axis, switch the discharge direction of the recording sheet from the nip A fixing device characterized by being configured .   Of the surface on the backup member side of the nip member, the portion pressed by the backup member when the nip member is in the first posture is the backup when the nip member is in the second posture. The fixing device according to claim 1, wherein the fixing device has a curvature different from a curvature of a portion pressed by the member.   The fixing device according to claim 1, further comprising: a release mechanism that releases the nip pressure by moving one of the nip member and the backup member away from the other. The fixing device according to claim 2, wherein the nip member is rotatable around the center of curvature of one of the portions having different curvatures.

Images