JP2016186577A - Fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress an endless belt from being damaged by an apical surface at an end of a reflecting plate.SOLUTION: A reflecting plate 140 comprises: a center part (base 141) that extends from the upstream side to the downstream side in a direction of conveyance of a support member (stay 150); a first bent part 143 that is bent from an end 141A on one side of the center part on the upstream side or the downstream side in the direction of conveyance to a position of the support member, in a direction orthogonal to a direction where a straight ling PF passing through the end 141A on the upstream side and an end 141B on the downstream side extends; and an extension part (lateral wall part 142) that extends from the first bent part 143, is arranged on one side of the support member, and includes an apical surface F1. The extension part includes a bent second bent part 142B, and at least a part of the second bent part 142B is located on the one side with respect to the apical surface F1.SELECTED DRAWING: Figure 2

Description

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

  Conventionally, a fixing device including an endless belt, a heater disposed inside the endless belt, a reflecting plate that reflects radiant heat from the heater, and a stay that supports the reflecting plate is known (see Patent Document 1). ). Specifically, in this technique, the end portion of the reflecting plate is disposed so as to overlap the stay from the outside, so that the end surface of the end portion of the reflecting plate is exposed toward the endless belt.

JP 2013-164438 A

  However, in the prior art, since the tip surface of the end portion of the reflecting plate is exposed toward the endless belt, the endless belt may come into sliding contact with the edge of the tip surface and be damaged. Such a problem may also occur when the endless belt is in sliding contact with the edge of the front end surface of the nip plate in a structure in which the nip plate that contacts the inner peripheral surface of the endless belt overlaps from the outside of the reflecting plate. Is expected.

  Accordingly, an object of the present invention is to prevent the endless belt from being damaged by a member disposed inside the endless belt, for example, the front end surface of the end portion of the reflecting plate.

In order to solve the above problems, a fixing device according to the present invention includes an endless belt, a heater disposed inside the endless belt, a nip member that contacts an inner peripheral surface of the endless belt, and radiant heat from the heater. A nip portion is formed by sandwiching the endless belt between the nip member and a reflector plate that reflects the nip member, the nip member and the reflector plate, and a support member that supports the nip member. And a backup member, and configured to convey the sheet in a predetermined conveyance direction at the nip portion.
The reflection plate extends from the upstream side to the downstream side in the transport direction of the support member, and has a central portion having an upstream end portion and a downstream end portion in the transport direction, and the central portion, In a cross section perpendicular to the longitudinal direction of the heater from the upstream end or the downstream end to the straight line passing through the upstream end and the downstream end. A first bent portion bent toward the side where the support member is located in an orthogonal direction; and an extended portion extending from the first bent portion and disposed on one side of the support member and having a distal end surface.
The extending portion has a bent second bent portion, and at least a part of the second bent portion is located on the one side with respect to the tip surface.

  According to this configuration, when at least a part of the second bent portion of the reflector is located on one side of the tip surface, the endless belt positioned on one side tries to approach the tip surface. Therefore, the endless belt can be prevented from coming into contact with the tip surface and being damaged.

  ADVANTAGE OF THE INVENTION According to this invention, it can suppress that an endless belt is damaged with the end surface of the edge part of a reflecting plate.

1 is a cross-sectional view illustrating a color laser printer including a fixing device according to an embodiment of the present invention. FIG. 4 is a cross-sectional view (a) showing the fixing device and an enlarged view (b) of the curled end portion. It is a disassembled perspective view which decomposes | disassembles and shows a nip board etc. FIG. It is a perspective view which shows a side guide. FIG. 3 is a diagram of the fixing device viewed from a conveyance direction. It is sectional drawing (a) which shows the modification 1 of this invention, and the enlarged view (b) of the curled edge part. It is sectional drawing which shows the modification 2 of this invention. It is sectional drawing which shows the modification 3 of this invention. It is sectional drawing which shows the modification 4 of this invention. It is sectional drawing which shows the modification 5 of this invention. It is sectional drawing which shows the modification 6 of this invention. It is sectional drawing which shows the modification 7 of this invention.

  Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. In the following description, unless otherwise specified, the vertical direction shown in FIG. 1 is up and down, the right side in FIG. 1 is front, the left side is rear, the front side of the paper is left, and the back side of the paper is right. Indicates.

  As shown in FIG. 1, the color laser printer 1 includes a paper feeding unit 5 that supplies paper 51, an image forming unit 6 that forms an image on the fed paper 51, and an image in the main body housing 2. A paper discharge unit 7 for discharging the formed paper 51.

  In the lower part of the main body housing 2, the paper feeding unit 5 supplies the image forming unit 6 with a paper feeding tray 50 that is attached to and detached from the main body housing 2 by a slide operation from the front side and the paper 51 in the paper feeding tray 50. And a sheet feeding mechanism M1 that feeds out.

  The paper feed mechanism M1 includes a pickup roller 52, a separation roller 53, a separation pad 54, and the like provided in the vicinity of the front end of the paper feed tray 50, so that one sheet of paper 51 in the paper feed tray 50 can be obtained. They are separated one by one and sent upward. The paper 51 transported upward passes through between the paper dust removing roller 55 and the pinch roller 56, and then is redirected backward through a transport path 57 formed by a wall member (not shown), which will be described later. Supplied on the conveyor belt 73.

  The image forming unit 6 includes a scanner unit 61, a process unit 62, a transfer unit 63, and a fixing device 100.

  The scanner unit 61 is provided in the upper part of the main body housing 2 and includes a laser light emitting unit, a polygon mirror, a plurality of lenses, and a reflecting mirror (not shown). In the scanner unit 61, a laser beam emitted from the laser beam emitting unit is scanned at high speed in the left-right direction by a polygon mirror in correspondence with each color of cyan, magenta, yellow, and black, and is passed or reflected by a plurality of lenses and reflecting mirrors. After that, each photosensitive drum 31 is irradiated.

  The process unit 62 is disposed below the scanner unit 61 and above the sheet feeding unit 5, and includes the photosensitive unit 3 that can move in the front-rear direction with respect to the main body housing 2. The photoreceptor unit 3 includes a drum subunit 30 and a developing cartridge 40 attached to the drum subunit 30.

The drum subunit 30 includes a known photosensitive drum 31 and a scorotron charger 32.
The developing cartridge 40 contains toner as an example of a developer, and includes a supply roller 41, a developing roller 42, a layer thickness regulating blade 43, and the like.

  Such a process unit 62 functions as follows. The toner in the developing cartridge 40 is supplied to the developing roller 42 by the supply roller 41, and at this time, the toner is frictionally charged between the supply roller 41 and the developing roller 42. The toner supplied to the developing roller 42 is rubbed by the layer thickness regulating blade 43 as the developing roller 42 rotates, and is carried on the surface of the developing roller 42 as a thin layer having a constant thickness.

  On the other hand, in the drum subunit 30, the scorotron charger 32 uniformly charges the photosensitive drum 31 by corona discharge. The charged photosensitive drum 31 is irradiated with laser from the scanner unit 61, and an electrostatic latent image is formed on the photosensitive drum 31.

  Thereafter, the toner carried on the developing roller 42 is supplied to the electrostatic latent image on the photosensitive drum 31. As a result, the electrostatic latent image on the photosensitive drum 31 is visualized, and a toner image by reversal development is carried on the surface of the photosensitive drum 31 corresponding to each color toner.

The transfer unit 63 includes a driving roller 71, a driven roller 72, a conveyance belt 73, a transfer roller 74, and a cleaning unit 75.
The driving roller 71 and the driven roller 72 are arranged in parallel apart from each other in the front-rear direction, and a conveyance belt 73 formed of an endless belt is wound around them. The outer surface of the conveyance belt 73 is in contact with each photosensitive drum 31. A transfer roller 74 is disposed inside the conveyor belt 73 so as to sandwich the conveyor belt 73 between the photosensitive drums 31. A transfer bias is applied to the transfer roller 74. At the time of image formation, the paper 51 transported by the transport belt 73 is sandwiched between the photosensitive drum 31 and the transfer roller 74, and the toner image on the photosensitive drum 31 is transferred to the paper 51.

  The cleaning unit 75 is disposed below the conveyance belt 73, removes toner adhering to the conveyance belt 73, and drops the removed toner in a toner storage unit 76 disposed below the cleaning belt 75.

  The fixing device 100 is provided behind the transfer unit 63 and thermally fixes the toner image transferred onto the paper 51 onto the paper 51. The fixing device 100 will be described in detail later.

  In the paper discharge unit 7, the paper discharge side conveyance path 91 of the paper 51 is configured by a wall member (not shown) and the like, and is formed to extend upward from the outlet of the fixing device 100 and to be reversed to the front side. A plurality of transport rollers 92 that transport the paper 51 are disposed in the middle of the paper discharge side transport path 91. A paper discharge tray 93 for accumulating the printed paper 51 is formed on the upper surface of the main body housing 2, and the paper 51 discharged from the paper discharge side transport path 91 by the transport roller 92 is placed on the paper discharge tray 93. Accumulated.

  2 and 3, the fixing device 100 includes a fixing belt 110 as an example of an endless belt, a halogen lamp 120 as an example of a heater, a nip plate 130 as an example of a nip member, and a reflective member. It mainly includes a reflecting plate 140 as an example, a stay 150 as an example of a support member, a heat insulating member 160, and a pressure roller 170 as an example of a backup member.

  In the following description, the transport direction (substantially front-rear direction) of the paper 51 is simply referred to as “transport direction”, and the width direction (substantially left-right direction) of the fixing belt 110 is simply referred to as “width direction”. The conveyance direction corresponds to the moving direction of the portion of the fixing belt 110 that contacts the nip plate 130, that is, the moving direction of the fixing belt 110 at a nip portion NP described later. The longitudinal direction of the halogen lamp 120 and the width direction of the fixing belt 110 are along the direction in which the rotation axis of the pressure roller 170 extends.

  The fixing belt 110 is an endless (cylindrical) belt having heat resistance and flexibility, and a force is applied to the rotation direction (hereinafter simply referred to as “rotation direction”) when the paper 51 is conveyed in the conveyance direction. Thus, both end portions in the axial direction are guided by side guides 180 (see FIGS. 4 and 5). The inner peripheral surface 111 of the fixing belt 110 is coated with grease for reducing frictional resistance with the nip plate 130 and the like.

  The fixing belt 110 may be configured as a metal belt having a metal base material and a resin coated on the outer periphery of the base material, or may be configured to have a rubber layer on the metal surface. The rubber layer may further have a non-metallic protective layer such as a fluorine coating on the surface. The base material of the fixing belt 110 may be a resin such as a polyimide resin.

  The halogen lamp 120 is a heating element that heats the toner on the paper 51 by heating the fixing belt 110, and is disposed inside the fixing belt 110 at a predetermined interval from the fixing belt 110.

  The nip plate 130 is disposed below the halogen lamp 120 and is in contact with the inner peripheral surface 111 of the fixing belt 110. The nip plate 130 includes a metal plate, and is formed by bending the metal plate into a substantially U shape in cross-sectional view. The metal plate may be an aluminum plate or a SUS plate.

  More specifically, the nip plate 130 is bent in a direction away from the pressure roller 170 from a base portion 131 extending along the transport direction and each end portion in the transport direction of the base portion 131 in a cross section orthogonal to the width direction. It mainly has a first bent portion 133 and a side wall portion 132 extending from the first bent portion 133 in a direction away from the pressure roller 170. Here, the direction away from the pressure roller 170 is a direction that intersects the recording sheet conveyance direction at the nip portion NP and is away from the pressure roller 170.

The base 131 is formed in a rectangular flat plate shape that is long in the width direction, and its lower surface is in contact with the inner peripheral surface 111 of the fixing belt 110.
The side wall portion 132 is formed in a rectangular flat plate shape that is long in the width direction, and has a plurality of insertion holes H1 through which claw portions 162A of a heat insulating member 160 described later are inserted at appropriate positions.

  The reflection plate 140 is a member that reflects radiant heat (light) from the halogen lamp 120 toward the inner peripheral surface 111 of the fixing belt 110 and directly hits the inner peripheral surface 111. It is arranged between the nip plate 130 (the base 131 described in detail later). In other words, the reflector 140 is disposed below the halogen lamp 120 and above the base 131 and reflects the radiant heat from the halogen lamp 120 upward, that is, in a direction away from the nip plate 130. That is, the radiant heat reflected by the reflecting surface of the reflecting plate 140 is irradiated in a direction away from the nip plate 130.

  The reflection plate 140 includes a metal plate, and is formed by bending the metal plate into a substantially U shape when viewed in cross section. The metal plate may be an aluminum plate or a SUS plate.

  More specifically, the reflecting plate 140 includes a base 141 as an example of a central portion extending along the transport direction and a pressure roller 170 from each end in the transport direction of the base 141 in a cross section orthogonal to the width direction. It mainly has a first bent portion 143 that is bent in the direction toward the upper side, and a side wall portion 142 as an example of an extending portion that extends in the direction from the first bent portion 143 toward the pressure roller 170. Here, the direction toward the pressure roller 170 is a direction that intersects the recording sheet conveyance direction at the nip portion NP and toward the pressure roller 170.

  The base 141 extends from the upstream side to the downstream side in the conveyance direction of the stay 150. In the cross section orthogonal to the width direction, the first bent portion 143 includes an upstream end portion 141A and a downstream end portion 141B of the base portion 141 from an upstream end portion 141A or a downstream end portion 141B of the base portion 141. It is bent toward the side where the stay 150 is located in the direction orthogonal to the direction in which the straight line PF passes.

  Each side wall 142 overlaps each side wall 132 of the nip plate 130 from the outside in the conveying direction, that is, from the fixing belt 110 side, and is disposed adjacent to each side wall 132. In other words, each side wall part 142 is arranged on the upstream side and the downstream side in the transport direction with respect to a nip part NP described later. In other words, the side wall portions 142 are disposed on the upstream side and the downstream side in the transport direction with respect to the stay 150.

  Each side wall part 142 has a main body part 142A extending downward from each first bent part 143 and a second bent part 142B formed continuously from the lower end of the main body part 142A. The main body portion 142A is formed in a flat plate shape orthogonal to the conveyance direction, and has a plurality of insertion holes H2 through which claw portions 162A of a heat insulating member 160 described later are inserted.

  Each second bent portion 142B is bent, specifically, curled so that the entire front end face F1 faces the main body portion 142A in a predetermined direction. Here, the bending includes not only curling but also bending. In addition, the predetermined direction refers to a direction orthogonal to the front end surface F1 when the front end surface F1 is a flat surface, and when the front end surface F1 is not flat, the second direction curled in the cross section orthogonal to the width direction. A direction along a straight line L1 that is in contact with the outer peripheral surface F5 of the bent portion 142B and passes through the edge E1 on the outer peripheral surface F5 side of the distal end surface F1 (see FIG. 2B). For example, the front end surface F1 is a cut surface generated by cutting a metal plate. In such a case, the front end surface F1 may be in a state where corners are generated. Moreover, the front end surface F1 is a bare surface, and is not fitted with a resin-like cap or the like, for example.

  A part of the second bent portion 142B arranged on the upstream side of the stay 150 in the conveying direction is located on the upstream side of the front end surface F1 and exposed on the inner peripheral surface 111 of the fixing belt 110 located on the upstream side. doing. Further, a part of the second bent portion 142B disposed on the downstream side in the conveyance direction of the stay 150 is located on the downstream side of the front end face F1 and the inner peripheral surface 111 of the fixing belt 110 located on the downstream side. Is exposed. Further, the front end surface F1 of the second bent portion 142B disposed on the upstream side in the transport direction of the stay 150 faces the downstream side in the transport direction, and the front end surface of the second bent portion 142B disposed on the downstream side in the transport direction of the stay 150. F1 faces the upstream side in the transport direction. Note that the second bent portion 142B is exposed at the inner peripheral surface 111 of the fixing belt 110 includes a line segment that connects the inner peripheral surface 111 and the second bent portion 142B without intersecting with other members. It means that.

  Specifically, each second bent portion 142B is bent by 90 ° or more toward the side opposite to the nip plate 130, and has a substantially circular shape in a cross-sectional view. That is, each of the second bent portions 142B has an outer-circular substantially circular shape that curves toward the side opposite to the nip plate 130. In other words, the inner peripheral surface F2 of each curled second bent portion 142B is connected to the outer surface F3 of the main body portion 142A, that is, the surface on the fixing belt 110 side. In other words, the second bent portion 142B disposed on the upstream side in the conveyance direction of the stay 150 bends in the direction opposite to the rotation direction of the fixing belt 110, and the second bent portion disposed on the downstream side in the conveyance direction of the stay 150. 142B is bent in the rotation direction of the fixing belt 110.

  Each of the second bent portions 142B curled in this way is formed from one end to the other end in the width direction of the side wall portion 142 of the reflecting plate 140.

  The stay 150 is a metal frame for ensuring the rigidity of the nip plate 130, and is disposed on the side opposite to the halogen lamp 120 with respect to the reflection plate 140, and supports the nip plate 130 via a heat insulating member 160. ing. The stay 150 is formed by bending a relatively rigid metal, such as a steel plate, into a substantially U shape in cross section.

  More specifically, the stay 150 extends in a direction orthogonal to the width direction from a base portion 151 extending along the transport direction and from each end portion in the transport direction of the base portion 151 in a direction away from the pressure roller 170. It mainly has a side wall 152. The stay 150 is longer than the nip plate 130, the reflecting plate 140, and the heat insulating member 160 in the width direction, and both ends thereof are fixed to the side guide 180 (see FIGS. 4 and 5). The side wall 142 arranged on the upstream side of the reflector 140 in the conveyance direction is located upstream of the stay 150 in the conveyance direction, and the side wall 142 arranged on the downstream in the conveyance direction is in the conveyance direction of the stay 150. Located downstream.

  The heat insulating member 160 is a resin member for preventing heat from being transmitted from the nip plate 130 to the stay 150, and is disposed between the nip plate 130 and the stay 150. It is formed into a shape. More specifically, the heat insulating member 160 mainly includes a base portion 161 extending along the transport direction and a side wall portion 162 extending upward from each end portion in the transport direction of the base portion 161 in a cross section orthogonal to the width direction. Have. The heat insulating member 160 is made of, for example, LCP (Liquid Crystal Polymer) which is a heat resistant resin.

  Each end portion 161A of the base portion 161 in the conveying direction is in contact with the nip plate 130 as a convex portion protruding downward from the central portion 161B. As a result, an air layer is formed between the central portion 161B and the nip plate 130.

  A plurality of claw portions 162A are formed on the outer surface, which is the outer surface in the conveyance direction, of the side wall portion 162 and protrudes outward from the outer surface in the conveyance direction. The claw portion 162A is formed so as to protrude from the side wall portion 162 to the outside in the transport direction, and its tip portion protrudes downward. The claw portion 162 </ b> A penetrates the insertion hole H <b> 1 of the nip plate 130 and the insertion hole H <b> 2 of the reflection plate 140, and the tip portion engages with the side wall portion 142 of the reflection plate 140 from the outside. .

  The pressure roller 170 is a member that sandwiches the fixing belt 110 with the nip plate 130 and forms a nip portion NP with the fixing belt 110, and is disposed below the nip plate 130. The pressure roller 170 includes a cylindrical roller main body 171 and a shaft 172 that is inserted into the roller main body 171 and is rotatable together with the roller main body 171. The roller body 171 is configured to be elastically deformable.

  The pressure roller 170 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 belt 110 (or the paper 51). The fixing belt 110 is driven to rotate by the frictional force.

  As shown in FIGS. 4 and 5, the side guide 180 is a member that guides the fixing belt 110 and is disposed so as to sandwich the fixing belt 110 in the width direction. The side guide 180 includes a guide main body 181 for supporting the stay 150 and the like, and an inner peripheral guide 182 for guiding the inner peripheral surface 111 of the fixing belt 110.

  The guide main body 181 has a support recess 181A that opens inward in the width direction, and the end of the stay 150 is fixed in the support recess 181A. Further, a metal plate (not shown) is provided in the support recess 181A, and the halogen lamp 120 is supported by the metal plate.

  The inner peripheral guide portion 182 is a wall having a circular arc shape in cross section that protrudes inward in the width direction from the inner surface in the width direction of the guide main body portion 181, and the outer peripheral surface guides the inner peripheral surface 111 of the fixing belt 110. It is a surface 182A. As shown in FIG. 2, each end portion in the circumferential direction of the inner circumferential guide portion 182 is disposed so as to sandwich the nip plate 130 in the transport direction.

  The guide surface 182A is disposed outside the curled second bent portion 142B of the reflecting plate 140 in the radial direction of the inner peripheral guide portion 182. That is, the curled second bent portion 142B is disposed on the inner side of the guide surface 182A when viewed in the width direction. In other words, the second bent portion 142B is disposed at a position farther from the fixing belt 110 than the guide surface 182A when viewed in the width direction.

  As shown in FIG. 5, the inner peripheral guide portion 182 overlaps with the edge EG in the width direction of the side wall portion 142 of the reflecting plate 140 when viewed from the transport direction. As a result, the inner peripheral guide portion 182 is disposed between the edge EG and the fixing belt 110, so that the edge EG is covered by the inner peripheral guide portion 182 from the fixing belt 110.

  Each side guide 180 is pressed downward by an elastic member such as a spring (not shown). As the side guides 180 are pressed by the elastic members in this way, a downward pressing force acts on the stay 150, and this pressing force is applied via the heat insulating member 160, the nip plate 130 and the fixing belt 110. It is transmitted to the pressure roller 170. Further, a reaction force against the pressing force is generated upward from the pressure roller 170, and this reaction force is received by the stay 150 via the fixing belt 110, the nip plate 130 and the heat insulating member 160. .

  On the contrary, by pressing the pressure roller 170 upward by the elastic member, the pressing force from the pressure roller 170 is applied to the stay 150 via the fixing belt 110, the nip plate 130, and the heat insulating member 160. You may comprise so that it may receive.

Next, operational effects during operation of the fixing device 100 will be described.
As shown in FIG. 2, when a driving force is applied to the pressure roller 170 to rotate the pressure roller 170, the fixing belt 110 rotates in the clockwise direction in the drawing so as to follow the rotation of the pressure roller 170. At this time, since both end portions of the fixing belt 110 are guided by the inner peripheral guide portion 182, movement toward the inside in the radial direction is restricted, so that each end portion of the fixing belt 110 is connected to each side wall portion of the reflecting plate 140. Interference with the edge EG in the width direction 142 can be suppressed.

  At this time, a portion of the fixing belt 110 that is not guided by the inner peripheral guide portion 182, for example, a central portion in the width direction, may move inward in the radial direction. In this case, the central portion in the width direction of the fixing belt 110 gradually approaches the front end surface F1 of the reflector plate 140, but before reaching the front end surface F1, the curled second bent portion 142B is easily contacted. Therefore, it is possible to prevent the fixing belt 110 from being damaged by contacting the front end face F1.

  As described above, according to the present embodiment, the following effects can be obtained in addition to the effects described above.

  Since the curled second bent portion 142B is disposed on the downstream side in the transport direction with respect to the nip portion NP, contact between the front end surface F1 of the side wall portion 142 on the downstream side in the transport direction and the fixing belt 110 can be suppressed. A portion of the fixing belt 110 on the downstream side in the conveyance direction from the nip portion NP is sent out from the nip portion NP, so that it is easily loosened on the downstream side in the conveyance direction, and the second bent portion 142B and the fixing belt 110 on the downstream side in the conveyance direction. , The second bent portion 142B on the downstream side in the transport direction does not have to be curled as in this embodiment. That is, the side wall portion on the downstream side in the transport direction of the reflecting plate may be formed in a flat plate shape orthogonal to the transport direction, and this side wall portion may be overlapped with the side wall portion on the downstream side in the transport direction of the nip plate from the outside.

  Since the curled second bent portion 142B is disposed on the upstream side in the transport direction with respect to the nip portion NP, contact between the front end surface F1 of the side wall portion 142 on the upstream side in the transport direction and the fixing belt 110 can be suppressed. In particular, a portion of the fixing belt 110 on the upstream side of the nip portion NP in the transport direction is easily drawn toward the tip surface F1 on the upstream side of the reflector plate 140 in the transport direction by being pulled into the nip portion NP. The effect of curling the second bent portion 142B on the side is easily exhibited.

  Since the second bent portion 142B is curved, the fixing belt 110 can be prevented from being damaged when the second bent portion 142B and the fixing belt 110 are in contact with each other, for example, compared to a configuration in which the end portion is bent at an acute angle.

  Since the inner peripheral surface F2 of the curled second bent portion 142B is connected to the outer surface F3 of the main body portion 142A, that is, the second bent portion 142B is bent outward with respect to the nip plate 130, the second bent portion The force applied to the nip plate 130 from 142B can be reduced. In other words, the second bent portion 142B disposed on the upstream side in the conveyance direction of the stay 150 bends in the direction opposite to the rotation direction of the fixing belt 110, and the second bent portion 142B disposed on the downstream side in the conveyance direction of the stay 150. However, since it is bent in the rotation direction of the fixing belt 110, the force applied to the nip plate 130 from the second bent portion 142B can be reduced.

  The front end face F1 of the second bent portion 142B arranged on the upstream side in the conveyance direction of the stay 150 faces the downstream side in the conveyance direction, and the front end surface F1 of the second bent portion 142B arranged on the downstream side in the conveyance direction of the stay 150 is conveyed. Since it faces toward the upstream side, it is possible to satisfactorily suppress the contact of the fixing belt 110 with the front end face F1.

  Since the curled second bent portion 142B is formed from one end to the other end of the reflecting plate 140 in the width direction, the second bent portion 142B curled with respect to the reflecting plate 140 can be easily formed. Specifically, for example, a plurality of locations in the width direction of the end portion of the reflector plate may be curled and other portions may not be curled. In this case, however, the end portions must be curled at each location. The step of curling the part needs to be performed a plurality of times for one end. On the other hand, in the present embodiment, since the end portion only needs to be curled over the entire width direction, the step of curling the end portion is only required once per end portion, and the manufacturing process can be simplified. it can.

  Since the edge EG in the width direction of the side wall 142 of the reflector 140 is covered from the fixing belt 110 by the side guide 180, the fixing belt 110 can be prevented from being damaged by the edge EG in the width direction of the second bent portion 142B.

  Since the curled second bent portion 142B is disposed inside the guide surface 182A when viewed from the width direction, the guide surface 182A can prevent the fixing belt 110 from approaching the second bent portion 142B. Therefore, it is possible to prevent the fixing belt 110 from being damaged by the sliding contact with the curled second bent portion 142B.

  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 following description, the same reference numerals are given to members having substantially the same structure as in the above embodiment, and the description thereof is omitted.

  In the above-described embodiment, the second bent portion 142B has a substantially circular shape with an outer winding. However, the present invention is not limited to this, and for example, as shown in FIG. 6, the second bent portion 242B has a substantially circular shape with an inner winding. It is good. Specifically, in this embodiment, the lower end portion of the main body portion 142A is bent obliquely outward, and the second bent portion 242B is formed in a substantially circular shape from the lower end portion of the main body portion 142A bent obliquely toward the inside. The entire front end face F1 is bent and faces the main body 142A in the predetermined direction. In other words, the second bent portion 242B disposed on the upstream side in the conveyance direction of the stay 150 is bent in the rotation direction of the fixing belt 110, and the second bent portion 242B disposed on the downstream side in the conveyance direction of the stay 150 is fixed. The belt 110 is bent in the direction opposite to the rotation direction.

  Further, in FIG. 6, the front end face F <b> 1 of the second bent part 242 </ b> B is covered with a main body part 142 </ b> A that is a part of the side wall part 142 of the reflecting plate 140 in the cross section orthogonal to the width direction. Specifically, the front end surface F1 disposed on the downstream side in the transport direction of the stay 150 is entirely opposed to the main body 142A in the direction of the straight line L1 described above, and is further covered on the downstream side by the main body 142A. Further, the front end surface F1 disposed on the upstream side in the transport direction of the stay 150 is entirely opposed to the main body 142A in the direction of the straight line L1 described above, and is further covered on the upstream side by the main body 142A. Thereby, the contact between the fixing belt 110 and the front end face F1 can be further suppressed.

  Further, in the cross section orthogonal to the width direction, the front end face F1 of the second bent portion 242B is surrounded by the reflecting plate 140 and the nip plate 130. Here, “being surrounded by the reflecting plate 140 and the nip plate 130” means that the entire front end face F1 faces the reflecting plate 140 in the direction of the straight line L1 described above in a cross section orthogonal to the width direction, and This means that the front end face F1 is sandwiched between the reflecting plate 140 and the nip plate 130 on the straight line L2 that is orthogonal to the straight line L1 and passes through the edge E1 on the outer peripheral surface F5 side. Therefore, for example, even when the second bent portion 242B is arranged slightly apart from the nip plate 130, the front end face F1 is surrounded by the reflecting plate 140 or the nip plate 130.

  The main body 142A may have a flat plate shape in which the lower end is not bent obliquely before the reflecting plate 140 is fitted into the nip plate 130. However, in this case, when the reflecting plate 140 is fitted into the nip plate 130, the lower end portion of the main body portion 142A is bent outward, so that the elastic return force of the main body portion 142A causes the second bent portion 242B to nip the nip plate. Power is applied to 130. Therefore, it is desirable that the main body portion 142A has a shape in which the lower end portion is bent obliquely as shown in FIG. 6 even before the reflecting plate 140 is fitted into the nip plate 130.

  The outer peripheral surface F5 of the curled second bent portion 242B is connected to the outer surface F3 of the main body portion 142A. The second bent portions 242B formed in this way are arranged on the upstream side and the downstream side in the transport direction with respect to the nip plate 130.

  As described above, the outer peripheral surface F5 of the second bent portion 242B on the upstream side in the transport direction is connected to the outer surface F3 of the main body portion 142A, so that the inner peripheral surface 111 of the fixing belt 110 is a boundary between the second bent portion 242B and the main body portion 142A. Even in the case of contact with the portion, the grease applied to the inner peripheral surface 111 of the fixing belt 110 is suppressed from entering the curled second bent portion 242B. In other words, the second bent portion 242B disposed on the upstream side in the conveyance direction of the stay 150 is bent in the rotation direction of the fixing belt 110, so that the inner peripheral surface 111 of the fixing belt 110 is connected to the second bent portion 242B and the main body portion. Even when it comes into contact with the boundary portion 142A, the grease applied to the inner peripheral surface 111 of the fixing belt 110 is prevented from entering the curled second bent portion 242B.

  Further, as shown in FIG. 7, the second bent portion 342B of the reflector 140 is formed in an arc shape that bends outward from the lower end of the main body portion 142A, and then curls inward, and has a tip end surface thereof. The whole of F1 may face obliquely downward so as to face the side wall portion 132 of the nip plate 130 in the predetermined direction. Even in this case, since the second bent portion 342B can prevent the fixing belt 110 from approaching the front end surface F1, the same effect as in the above-described embodiment can be obtained.

  Also, as shown in FIG. 8, the second bent portion 442B of the reflector 140 is formed in a substantially semicircular shape that bends outward from the lower end of the main body portion 142A and then curls inward, The entire front end face F <b> 1 may be in contact with the side wall part 132 of the nip plate 130. According to this, it is possible to suppress the fixing belt 110 from coming into contact with the front end face F1 as compared with the embodiment shown in FIG.

  Further, as shown in FIG. 9, the lower end portion of the main body portion 142A is bent obliquely outward, and the second bent portion 542B is folded inward from the obliquely bent lower end portion of the main body portion 142A. May be. That is, the entire front end surface F1 of the second bent portion 542B is a surface facing the lower end portion of the side wall portion 132 of the nip plate 130, which is bent obliquely, of the main body portion 142A in the predetermined direction. The second bent portion 542B may be bent so as to face. According to this, it is possible to suppress the fixing belt 110 from coming into contact with the front end face F1 as compared with the embodiment shown in FIG.

  In the embodiment, the side wall 142 of the reflector 140 is overlapped from the outside of the side wall 132 of the nip plate 130, but the present invention is not limited to this, and as shown in FIG. 10, the side wall 132 of the nip plate 130. May be superimposed on the side wall 142 of the reflector 140 from the outside. Specifically, in this embodiment, the nip plate 130 includes the base portion 131 as an example of a central portion, the first bent portion 133, and a side wall portion 132 as an example of an extension portion. The side wall portion 132 of the nip plate 130 has a flat plate-like main body portion 132A orthogonal to the transport direction, and second bent portions 132B and 132C that are curled from the upper end of the main body portion 132A.

  Specifically, the base 131 extends from the upstream side to the downstream side in the conveying direction of the stay 150. The first bent portion 133 is bent from the end portions 131A and 131B in the conveying direction of the base portion 131 to the side where the stay 150 is located in the direction orthogonal to the extending direction of the straight line PF passing through the end portions 131A and 131B. .

  A part of the second bent portion 132B disposed on the upstream side in the transport direction of the stay 150 is disposed on the upstream side in the transport direction with respect to the front end face F1, and the second bent portion is disposed on the downstream side in the transport direction of the stay 150. A part of 132C is arranged on the downstream side in the transport direction from the front end face F1. Accordingly, contact between the front end surface F1 of the side wall portion 132 on the upstream side in the transport direction and the fixing belt 110 can be suppressed, and contact between the front end surface F1 of the side wall portion 132 on the downstream side in the transport direction and the fixing belt 110 can be suppressed. be able to.

  The second bent portion 132B on the upstream side in the transport direction has an outer winding shape, and the second bent portion 132C on the downstream side in the transport direction has an inner winding shape. Specifically, the outer peripheral surface F5 of the second bent portion 132C on the downstream side in the transport direction is connected to the outer surface F3 of the main body portion 132A. In other words, the second bent portion 132B on the upstream side in the transport direction and the second bent portion 132C on the downstream side in the transport direction are bent in the rotation direction of the fixing belt 110.

  Thus, in the configuration in which the second bent portions 132B and 132C of the nip plate 130 are curled, the outer peripheral surface F5 of the second bent portion 132C on the downstream side in the transport direction is connected to the outer surface F3 of the main body portion 132A, thereby It is possible to prevent the grease applied to the inner peripheral surface 111 from entering the curled second bent portion 132C. In other words, by bending the second bent portion 132C on the downstream side in the conveying direction in the rotation direction of the fixing belt 110, the grease applied to the inner peripheral surface 111 of the fixing belt 110 is curled inside the second bent portion 132C. Intrusion can be suppressed.

  As shown in FIG. 11, the side wall 142 of the reflector 140 is overlapped from the outside of the side wall 132 of the nip plate 130 on one side, for example, on the downstream side in the transport direction, and on the other side, for example, on the upstream side. The side wall part 132 may overlap the side wall part 142 of the reflector 140 from the outside. In this case, if the curled second bent portion 142B is provided on the side wall portion 142 of the downstream reflecting plate 140, and the curled second bent portion 132B is provided on the side wall portion 132 of the upstream nip plate 130. Good.

  Further, as shown in FIG. 12, the side wall portion 142 may be configured such that the front end face F1 of the side wall portion 142 faces the fixing belt 110 in the predetermined direction. Specifically, in this embodiment, the side wall portion 142 on the upstream side in the transport direction includes a main body portion 142A, a third bent portion 142C that bends from the lower end portion of the main body portion 142A to the upstream side in the transport direction, and a third bent portion 142C. It has a second bent portion 142D bent in an arc shape in cross section and a fourth bent portion 142E bent downward from the second bent portion 142D, and the end surface of the fourth bent portion 142E is the tip surface F1. . The second bent portion 142D is formed in an arc shape in sectional view that opens to the downstream side in the transport direction.

  The side wall 142 on the downstream side in the transport direction is a main body 142A, a third bent portion 142C that bends from the lower end of the main body 142A to the downstream in the transport direction, and a third bent portion 142C that is bent in an arc shape in cross section from the third bent portion 142C. There are two bent portions 142D and a fourth bent portion 142E bent downward from the second bent portion 142D, and the end surface of the fourth bent portion 142E is the tip surface F1. The second bent portion 142D is formed in an arc shape in sectional view that opens to the upstream side in the transport direction.

  The second bent portion 142D on the upstream side in the transport direction is located on the upstream side in the transport direction with respect to the front end surface F1 on the upstream side in the transport direction, and the second bent portion 142D on the downstream side in the transport direction is the front end on the downstream side in the transport direction. It is located downstream of the surface F1 in the transport direction. Thereby, it is possible to suppress the fixing belt 110 from coming into contact with the respective front end surfaces F1 on the upstream side and the downstream side in the transport direction.

  In the embodiment, the halogen lamp 120 is exemplified as an example of the heater, but the present invention is not limited to this, and the heater may be a carbon heater or the like.

  In each of the above embodiments, the plate-shaped nip plate 130 and the reflection plate 140 are illustrated as an example of the nip member and the reflection member, but the present invention is not limited to this, and the nip member and the reflection member are not thick, for example. It may be a member.

  In the above embodiment, the present invention is applied to the color laser printer 1, but the present invention is not limited to this, and the present invention may be applied to other image forming apparatuses such as a copying machine and a multifunction machine.

  In the embodiment, the pressure roller 170 is exemplified as a backup member that sandwiches the endless belt with the nip member. However, the present invention is not limited to this, and may be a belt-like pressure member, for example. .

  In the above embodiment, the stay 150 is exemplified as the support member, but the present invention is not limited to this, and may be the heat insulating member 160, for example.

  In the said embodiment, although the base 131 and the base 141 extended along the conveyance direction, they should just extend from the upstream in the conveyance direction of a support member to the downstream, for example, may be curved on the way.

DESCRIPTION OF SYMBOLS 100 Fixing device 110 Fixing belt 120 Halogen lamp 130 Nip plate 140 Reflecting plate 141 Base portion 141A, 141B End portion 142 Side wall portion 143 First bent portion 142B Second bent portion 150 Stay F1 Tip surface PF Straight line

Claims (14)

Endless belt,
A heater disposed inside the endless belt;
A nip member that contacts an inner peripheral surface of the endless belt;
A reflector that reflects radiant heat from the heater;
A support member that is disposed between the nip member and the reflector and supports the nip member;
A backup member that forms a nip portion by sandwiching the endless belt with the nip member, and a fixing device that conveys a sheet in a predetermined conveyance direction at the nip portion,
The reflector is
A central portion extending from the upstream side in the transport direction of the support member to the downstream side, having an upstream end in the transport direction, and a downstream end,
A straight line passing through the upstream end and the downstream end from the upstream end or the downstream end of the central portion, and the length of the heater A first bent portion bent toward the side where the support member is located in a direction orthogonal to the cross section orthogonal to the direction;
Extending from the first bent portion, disposed on one side of the support member, and having a distal end surface,
The extending portion has a bent second bent portion,
At least a part of the second bent portion is located on the one side with respect to the front end surface.   The fixing device according to claim 1, wherein the one side is a downstream side in the transport direction. Rotating the endless belt in the rotation direction, and moving the endless belt in the conveyance direction at the nip portion;
The one side is an upstream side in the transport direction,
The fixing device according to claim 1, wherein the second bent portion is bent in the rotation direction of the endless belt. Endless belt,
A heater disposed inside the endless belt;
A nip plate in contact with the inner peripheral surface of the endless belt;
A reflective member that reflects radiant heat from the heater;
A support member that is disposed between the nip plate and the reflective member and supports the nip plate;
And a backup member that forms a nip portion by sandwiching the endless belt with the nip plate, and a fixing device that conveys a sheet in a predetermined conveyance direction at the nip portion,
The nip plate is
A central portion extending from the upstream side in the transport direction of the support member to the downstream side, having an upstream end in the transport direction, and a downstream end,
A straight line passing through the upstream end and the downstream end from the upstream end or the downstream end of the central portion, and the length of the heater A first bent portion bent toward the side where the support member is located in a direction orthogonal to the cross section orthogonal to the direction;
Extending from the first bent portion, disposed on one side of the support member, and having a distal end surface,
The extending portion has a bent second bent portion,
At least a part of the second bent portion is located on the one side with respect to the front end surface.   The fixing device according to claim 4, wherein the one side is an upstream side in the transport direction. Rotating the endless belt in the rotation direction, and moving the endless belt in the conveyance direction at the nip portion;
The one side is a downstream side in the transport direction,
The fixing device according to claim 4, wherein the second bent portion is bent in the rotation direction of the endless belt. Rotating the endless belt in the rotation direction, and moving the endless belt in the conveyance direction at the nip portion;
6. The fixing device according to claim 1, wherein the second bent portion is bent in a direction opposite to the rotational direction of the endless belt. 7. .   The fixing device according to any one of claims 1 to 7, wherein the leading end surface faces a side opposite to the one side in the transport direction.   The fixing device according to claim 1, wherein the leading end surface is covered with a part of the extending portion.   The fixing device according to claim 9, wherein the one end side is covered with a part of the extending portion.   The fixing device according to claim 1, wherein the second bent portion is formed from one end to the other end of the extending portion in a longitudinal direction of the heater. A side guide for guiding the endless belt;
The fixing device according to claim 1, wherein the side guide is located between an edge of the extension portion in a longitudinal direction of the heater and the endless belt. . A side guide for guiding the endless belt;
The side guide has a guide surface that guides an inner peripheral surface of the endless belt,
The said 2nd bending part is arrange | positioned in the position far from the said endless belt rather than the said guide surface seeing from the longitudinal direction of the said heater, The any one of Claims 1-12 characterized by the above-mentioned. The fixing device according to 1. Endless belt,
A heater disposed inside the endless belt;
A nip member that contacts an inner peripheral surface of the endless belt;
A reflective member that reflects radiant heat from the heater;
A support member disposed between the nip member and the reflective member and supporting the nip member;
A backup member that forms a nip portion by sandwiching the endless belt with the nip member, and a fixing device that conveys a sheet in a predetermined conveyance direction at the nip portion,
At least one of the nip member and the reflecting member is a plate-shaped member,
The one member is
A central portion extending from the upstream side in the transport direction of the support member to the downstream side, having an upstream end in the transport direction, and a downstream end,
A straight line passing through the upstream end and the downstream end from the upstream end or the downstream end of the central portion, and the length of the heater A first bent portion bent toward the side where the support member is located in a direction orthogonal to the cross section orthogonal to the direction;
Extending from the first bent portion, disposed on one side of the support member, and having a distal end surface,
The extending portion has a bent second bent portion,
At least a part of the second bent portion is located on the one side with respect to the front end surface.

Images