JP2017009881A - Fixation device and image formation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixation device and an image formation apparatus which can maintain the action of efficiently heating a fixation belt with the reflection shape of a reflection member even if a deflection occurs in a nip formation member.SOLUTION: A fixation device 12 comprises: an endless rotor 38 which is provided in a rotatable manner; a contact member 30 which contacts the outer peripheral surface of the rotor; a nip formation member 60 which contacts the contact member via the rotor and forms a nip part SN; a heating element 50 which is arranged on the inner side of the rotor; and a reflection member 40 which reflects the radiation heat emitted from the heating element toward the nip formation member with the reflection surface. The fixation device has: arranged therein the heating element so as to face the side surface of a reinforcement part standing from a sliding and rubbing part sliding in a rubbing manner on the inner peripheral surface of the rotor in the nip formation member; and the reflection shape of reflecting the radiation heat in the direction not heading toward the heating element at a position facing the heating element on the reflection surface of the reflection member. The fixation device also comprises reflection member attachment means 44, 51 which attach the reflection member to the heating element independently of the reinforcement part.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fixing device and an image forming apparatus.

  Conventionally, as a fixing device with a short warm-up time, a rotating cylindrical fixing belt and a contact member that contacts the outer peripheral surface of the fixing belt are provided, and the fixing belt is heated by a heating element disposed inside the fixing belt. An image forming apparatus including a belt fixing device is known.

  Japanese Patent Application Laid-Open No. 2004-151561 describes a belt fixing device that includes a nip forming member that forms a fixing nip by pressing the fixing belt against a contact member from the inside of the fixing belt. The nip forming member provided in the fixing device includes a rubbing portion where the inner periphery of the fixing belt is slidably contacted, and a plate-shaped reinforcing portion standing from the rubbing portion toward the inside of the fixing belt. In addition, heating elements are arranged on both sides of the reinforcing portion. Further, a reflecting member that reflects the radiant heat from the heating element is disposed at a position facing the heating element on both side surfaces of the portion where the reinforcing portion stands. The reflecting member has a mountain shape that protrudes toward the heating element with the position facing the heating element as a vertex.

  In the fixing device described in Patent Document 1, the radiant heat radiated from the heating element is incident on the angled slope of the reflecting member and reflected. At this time, the incident angle of the radiant heat incident on the inclined surface of the reflecting member is not perpendicular to the inclined surface. For this reason, the reflecting member reflects the radiant heat in a direction different from the direction in which the radiant heat is incident. Therefore, it is considered that the fixing belt can be efficiently heated by preventing the reflected radiant heat from going to the heating element and preventing the radiant heat from heating the heating element itself.

  However, the reflecting member described in Patent Document 1 is formed integrally with the reinforcing portion of the nip forming member that contacts the contact member with the fixing belt interposed therebetween. The nip forming member disposed inside the fixing belt is fixed to the apparatus main body at both axial ends parallel to the rotation axis of the fixing belt. Therefore, the nip forming member is bent toward the inside of the fixing belt by the contact pressure with the contact member. As a result, the reflecting member formed integrally with the reinforcing portion of the nip forming member is deformed following the bending of the reinforcing portion, and the apex of the mountain shape of the reflecting member and the heating element in the direction in which the reinforcing portion rises. Deviation occurs in the position. Due to this positional shift, there is a possibility that the effect of efficiently heating the fixing belt cannot be obtained by providing the above-described mountain shape.

  In addition, the shape that reflects the radiant heat toward the direction different from the direction in which the radiant heat enters is not limited to the above-described mountain shape. Similar problems may occur if the reflective shape can reflect radiant heat in a direction different from the heating element, such as a convex portion having a curved surface or a concave portion having a slope inclined with respect to the incident direction of radiant heat. In addition, the configuration in which the heating element is provided on both sides with the reinforcing portion standing toward the inside of the fixing belt has been described, but the same problem may occur in the configuration in which the heating element is provided only on one side of the reinforcing portion.

  In order to solve the above-described problems, the present invention provides an endless rotating body that is rotatably provided, a contact member that is in contact with an outer peripheral surface of the rotating body, and the rotating body that is disposed inside the rotating body. A nip forming member that contacts the contact member to form a nip portion, a heating element disposed inside the rotating body, and disposed inside the rotating body, from the heating element toward the nip forming member A reflecting member that reflects the radiant heat radiated by the reflecting surface, and the nip forming member includes a rubbing portion that rubs against an inner peripheral surface of the rotating body, and an inner side of the rotating body from the rubbing portion. And the heating element is disposed so as to face the side surface of the standing part of the reinforcing part, and the reflecting member is located at a position facing the heating element on the reflecting surface. Radiant heat radiated from the heating element is converted into the heating element. In the fixing device having a reflection geometry for reflecting in the direction not directed, and having a reflecting member mounting means for mounting the reflecting member to the heat generating element independently from the reinforcing portion.

  As described above, according to the present invention, there is an excellent effect that even when the nip forming member is bent, the operation of efficiently heating the fixing belt can be maintained by the reflection shape of the reflecting member.

FIG. 3 is a schematic diagram of the fixing device viewed from the left side of FIG. 2. 1 is a schematic configuration diagram of an image forming apparatus according to an embodiment. 1 is a schematic diagram of a fixing device according to an embodiment. The figure used for description of the problem in the conventional fixing device. (A) Schematic top view schematically showing the fixing device viewed from above when the pressure roller is not biased toward the fixing belt, and (b) the pressure roller is directed toward the fixing belt. FIG. 3 is a schematic top view schematically showing the fixing device as viewed from above at the time of press-contacting biased. The perspective view which shows the state which attached the reflector to the halogen heater. Explanatory drawing about attachment of a halogen heater and a reflector. The schematic diagram at the time of attaching a reflector to a halogen heater using a member different from a reflector. FIG. 3 is a schematic diagram of a fixing device in a lateral conveyance configuration. FIG. 3 is a schematic diagram of a fixing device in a vertical conveyance configuration. FIG. 4 is a schematic diagram of a fixing device provided with a rotation restricting protrusion that restricts rotation of the reflector. FIG. 3 is a schematic diagram of a fixing device in which a rotation restricting protrusion is provided by adding a flat portion to an inclined portion of a reflector. The schematic diagram of the fixing device which provided the space | gap between the stay and the reflector and installed the reflector. The schematic block diagram of a fixing device provided with an arc-shaped part in the reflective surface of a reflector.

  FIG. 2 is a schematic configuration diagram of the image forming apparatus according to the present embodiment. As shown in FIG. 2, a printer as an example of an image forming apparatus according to the present embodiment includes a paper feeding device 4, a registration roller pair 6, a photosensitive drum 8 as an image carrier, a transfer device 10, It has a fixing device 12 and the like.

  The paper feeding device 4 feeds the paper P as a recording material stored in a stacked state and the paper P stored in the paper feeding tray 14 one by one in order from the top. It has a roller 16 and the like. The paper P delivered by the paper supply roller 16 is temporarily stopped by the registration roller pair 6 to correct the posture deviation. Thereafter, at the timing synchronized with the rotation of the photosensitive drum 8, that is, at the timing at which the leading edge of the toner image formed on the photosensitive drum 8 coincides with the predetermined position at the leading edge of the sheet P in the transport direction. The pair 6 is sent to the transfer portion N.

  Around the photosensitive drum 8, the charging roller 18, the mirror 20 constituting a part of the exposure unit, the developing device 22 including the developing roller 22a, the transfer device 10, and the cleaning are arranged in order of the photosensitive drum rotation direction. A cleaning device 24 provided with a blade 24a is disposed. Between the charging roller 18 and the developing device 22, exposure light Lb is irradiated to the exposure unit 26 on the photosensitive drum 8 through the mirror 20 and scanned.

  The image forming operation in the printer is performed in the same manner as in the past. That is, when the photosensitive drum 8 starts to rotate, the surface of the photosensitive drum 8 is uniformly charged by the charging roller 18, and the exposure light Lb is irradiated and scanned on the exposure unit 26 based on the image data to create an image to be created. A latent image corresponding to is formed. The latent image is moved to a position facing the developing device 22 by the rotation of the photosensitive drum 8, where toner is supplied from the developing device 22 to the latent image to be visualized to form a toner image. The toner image formed on the photosensitive drum 8 is transferred onto the paper P that has entered the transfer portion N at a predetermined timing by applying a transfer bias by the transfer device 10. The paper P to which the toner image has been transferred is conveyed toward the fixing device 12, and after the toner image is fixed on the paper P by the fixing device 12, the paper P is discharged to the paper discharge tray and stacked.

  Residual toner remaining on the photosensitive drum 8 without being transferred from the photosensitive drum 8 to the paper P at the transfer portion N reaches the cleaning device 24 as the photosensitive drum 8 rotates, and is scraped off by the cleaning blade 24a. Thus, the surface of the photosensitive drum is cleaned. Thereafter, the residual potential on the photosensitive drum 8 is removed by the charge eliminating means, and is prepared for the next image forming step.

  FIG. 3 is a schematic diagram of the fixing device 12 according to the present embodiment. The fixing belt 38 has a nickel (NI) base having an outer diameter of 30 [mm] and a thickness of 10 [μm] to 70 [μm], and an elastic layer coated on the surface of the base. . The elastic layer is made of silicone rubber and has a thickness of 50 [μm] to 150 [μm]. The outermost layer of the fixing belt 38 is formed with a release layer having a thickness of 5 [μm] to 50 [μm] using a fluorine-based resin such as PFA or PTFE in order to enhance durability and secure release properties. The The base of the fixing belt 38 is not limited to nickel, and may be a metal base such as stainless steel or a heat resistant resin such as polyimide (PI).

  The pressure roller 30 has an outer diameter of 30 [mm], and is formed of a hollow metal core 30a, and an elastic layer 30b and a release layer 30c formed on the surface of the core 30a. The elastic layer 30b is made of silicone rubber and has a thickness of 5 [mm]. It is desirable to form a release layer 30c made of a fluororesin having a thickness of about 40 [μm] on the surface of the elastic layer 30b in order to improve the release property. The pressure roller 30 is urged by urging means and is in pressure contact with the fixing belt 38.

  The pressure pad 60 is made of a resin having high heat resistance such as LCP, and is in sliding contact with the inner surface of the fixing belt 38 to press the pressure roller 30 to form a fixing nip SN. The pressure pad 60 is supported by a stay 61, which is a reinforcing portion that reinforces the pressure pad 60 from the inside, with respect to the pressing force of the pressure roller 30 against the pressure pad 60. The stay 61 is supported at both ends in the longitudinal direction by both side plates of the fixing device 12, and receives the pressing force received by the pressure pad 60 from the pressure roller 30.

  The two halogen heaters 50a and 50b are arranged opposite to each other across the stay 61, and both longitudinal ends of the halogen heaters 50a and 50b are supported by brackets 82a and 82b (see FIG. 1). In the halogen heater 50a, the light emitting filaments are arranged in the longitudinal direction in a narrow area corresponding to the width of the small size paper. In the halogen heater 50b, light emitting section filaments are arranged in the longitudinal direction in a region other than the small size paper width in the wide region corresponding to the large size paper width. In the following description, the halogen heater 50a and the halogen heater 50b may be simply referred to as the halogen heater 50 unless they are particularly distinguished.

  The reflectors 40a and 40b are arranged in contact with or adjacent to the side surfaces of the stay 61 facing the halogen heaters 50a and 50b, respectively. The reflectors 40a and 40b are attached to the halogen heaters 50a and 50b as will be described later. The reflectors 40a and 40b are formed of an aluminum base and a silver paste applied to the surface of the base, and the radiant heat of the halogen heaters 50a and 50b is regularly reflected on the fixing belt 38, respectively. The reflectors 40 a and 40 b are formed in a polygonal shape so as to block the halogen heaters 50 a and 50 b, the stay 61 and the pressure pad 60. In addition, at the positions where the centers of the halogen heaters 50a and 50b and the reflectors 40a and 40b intersect perpendicularly, mountain-shaped portions 42a and 42b having apexes 41a and 41b as the positions are formed in the reflectors 40a and 40b. By providing such mountain-shaped portions 42a and 42b in the reflectors 40a and 40b, among the radiant heat irradiated from the halogen heaters 50a and 50b, the radiant heat incident on the reflecting surfaces 43a and 43b along the vertical line is Incident on the slopes of the mold-shaped portions 42a and 42b. At this time, since the incident direction of the radiant heat is not perpendicular to the slopes of the mountain-shaped portions 42a and 42b, the radiant heat is reflected in a direction different from the incident direction. Therefore, the radiant heat incident on the reflecting surfaces 43a and 43b can be reflected toward the fixing belt 38 while avoiding the passage of the halogen heaters 50a and 50b, and the radiant heat can be prevented from heating the halogen heaters 50a and 50b themselves. In the following description, the reflector 40a and the reflector 40b may be simply referred to as the reflector 40 unless otherwise distinguished.

  Here, conventional problems will be described using the fixing device according to the comparative example. The basic configuration of the fixing device according to the comparative example is the same as the configuration of the fixing device 12 according to the embodiment, except that the reflectors 40 a and 40 b are fixed to the stay 61. FIG. 4 is a perspective explanatory view of a fixing device according to a comparative example. In FIG. 4, the fixing belt 38 is removed, and for convenience, only the trajectory of the fixing belt 38 is indicated by a broken line. Further, the halogen heater 50b and the reflector 40b are also removed. FIG. 5A is a schematic top view of the fixing device as viewed from above when the pressure roller 30 is not biased toward the fixing belt 38 and is not pressed. FIG. 5B is a schematic top view of the fixing device as viewed from above during pressure contact in which the pressure roller 30 is urged toward the fixing belt 38.

  As shown in FIG. 4, the fixing device according to the comparative example is configured to support the reflector 40 a by the stay 61, and the reflector 40 a is fixed to the both ends in the longitudinal direction of the stay 61 by screws 71 a and 72 a. As shown in FIG. 5A, at the time of non-pressure welding, the apex 41a of the chevron shaped portion 42a of the reflector 40a is the center of the halogen heater 50a in the lateral direction of the apparatus (direction parallel to the X axis in the figure). It matches the position.

  At the time of pressure contact, the pressure roller 30 is urged toward the fixing belt 38, and pressure is applied to the stay 61 via the fixing belt 38 and the pressure pad 60. When a pressure is applied to the stay 61, the stay 61 is deformed such that the central portion in the longitudinal direction is separated from the pressure roller 30 as shown in FIG. At this time, the reflector 40 a is deformed following the stay 61, and the vertex 41 a of the mountain-shaped portion 42 a described above is displaced so that the central portion in the longitudinal direction is separated from the pressure roller 30. For this reason, the position where the position of the vertex 41a of the mountain-shaped part 42a of the reflector 40a and the center position of the halogen heater 50a shift | deviate significantly arises about the apparatus horizontal direction. As a result, the incident radiant heat cannot be reflected to the fixing belt 38 while avoiding the passage of the halogen heater 50a, and the belt heating efficiency is lowered. In the above description of the fixing device of the comparative example, the halogen heater 50a has been described. However, the same problem arises with the halogen heater 50b positioned on the opposite side of the halogen heater 50a with the stay 61 interposed therebetween.

  FIG. 6 is a perspective view showing a state in which the reflector 40 is attached to the halogen heater 50. FIG. 7 is an explanatory diagram for the attachment of the halogen heater 50 and the reflector 40. FIG. 1 is a schematic view of the fixing device 12 as viewed from the side opposite to the pressure roller 30 side. In the fixing device 12 according to the present embodiment, as shown in FIG. 6, the fitting portion 44 provided at the longitudinal end portion of the reflector 40 and the fitted portion provided at the longitudinal end portion of the halogen heater 50. The reflector 40 is attached to the halogen heater 50 by fitting with a certain insulator 51. The fitting portion 44 of the reflector 40 and the lever portion 51 of the halogen heater 50 function as a reflector mounting means for attaching the reflector 40 to the halogen heater 50. As shown in FIG. 1, the insulator portions 51 a and 51 b of the halogen heaters 50 a and 50 b are held by brackets 82 a and 82 b attached to the side plates 81 A and 81 B at both ends in the longitudinal direction of the fixing device 12. Further, the inner portions of the insulators 51a and 51b of the halogen heaters 50a and 50b with respect to the side plates 81A and 81B are fitted to the fitting portions 44a and 44b, and the reflector 40 is attached to the halogen heaters 50a and 50b.

  In the present embodiment, as shown in FIG. 7, the plate-like fitting portion 44 having a notch shape in which the insulator portion 51 of the halogen heater 50 is fitted to the reflector 40 at a certain angle is provided on the reflector 40. It is made upright from the reflecting surface 43 at the end in the longitudinal direction. When the reflector 40 is attached to the halogen heater 50, the lever 51 of the halogen heater 50 is fitted into the fitting portion 44 of the reflector 40 only in the posture shown in FIG. It is possible. Then, after the lever part 51 of the halogen heater 50 is fitted into the fitting part 44 of the reflector 40, the lever part 51 of the halogen heater 50 is rotated to the posture shown in FIG. Thereby, it can suppress that fitting with the fitting part 44 of the reflector 40 and the insulator part 51 of the halogen heater 50 removes unintentionally.

  Further, since the reflector 40 can rotate with respect to the center O of the halogen heater 50 by such a structure, as shown in FIG. 7C, the apex 41 of the mountain-shaped portion 42 of the reflector 40 and the halogen heater It is possible to always keep the 50 center O in agreement. Further, the reflector 40 is attached to the halogen heater 50 independently of the stay 61, and the reflector 40 is not fixed to the stay 61. For this reason, the apex 41 of the chevron shaped portion 42 provided in the reflector 40 and the center O of the halogen heater 50 always coincide with each other regardless of the deflection of the stay 61 and the component tolerance.

  The reflector 40 is attached to the halogen heater 50 as shown in FIGS. 1 and 6 and the like. The fitting portion 44 provided by machining the longitudinal end of the reflector 40 and the insulator portion of the halogen heater 50 are provided. It is not restricted to what fits 51. FIG. FIG. 8 is a schematic diagram of the fixing device 12 in which the reflector 40 is attached to the halogen heater 50 using a holder 90 that is a separate member from the reflector 40. In the fixing device 12 shown in FIG. 8, the reflector 40 is installed in a holder 90 that is a separate member from the reflector 40, and the reflector 40 is attached to the halogen heater 50 using the holder 90. Further, it is desirable to use a material having high rigidity such as stainless steel for the holder 90. Thereby, deformation of the reflector 40 at the time of assembly can be suppressed, and the positional relationship in which the apex 41 of the mountain-shaped portion 42 of the reflector 40 and the center O of the halogen heater 50 coincide with each other with high accuracy can be maintained. it can.

  FIG. 9 is a schematic diagram of the fixing device 12 adopting the configuration of the lateral conveyance method. FIG. 10 is a schematic diagram of the fixing device 12 adopting the configuration of the vertical conveyance method. FIG. 11 is a schematic diagram of the fixing device 12 provided with a rotation restricting plate 91 that restricts the rotation of the reflector 40 b located below the stay 61. When the reflector 40 is attached so as to be rotatable with respect to the halogen heater 50, as shown in FIG. Never do. On the other hand, as shown in FIG. 10, when the fixing device 12 has a configuration of the vertical conveyance system, the reflector 40b positioned below the stay 61 approaches the halogen heater 50b side by gravity, and the halogen heater 50b and the reflector 40b May come into contact. Therefore, as shown in FIG. 11, the rotation restricting plate 91 is provided on the lower end surface of the stay 61, and the projection 91a provided on the rotation restricting plate 91 and the reflecting surface 43b of the reflector 40b come into contact with each other, whereby the halogen of the reflector 40b. The rotation to the heater 50b side is restricted. Thereby, it can prevent that the reflector 40b rotates by gravity and contacts the halogen heater 50b.

  Note that the rotation restricting plate 91 is installed in a non-heat generation region located on the outer side in the longitudinal direction (end portion in the longitudinal direction of the halogen heater) than the heat generation region of the halogen heater 50b in order to suppress a decrease in the reflection efficiency of the reflector 40b. desirable. On the other hand, when the rotation restricting plate 91 is installed in the non-heat generation area located outside the heat generation area of the halogen heater 50b, the reflection surface 43b of the reflector 40b is formed in the longitudinal direction up to a position corresponding to the non-heat generation area. It must lead to an increase in cost. Accordingly, as shown in FIG. 12, pressure is applied from the inclined surface of the reflecting surface 43b of the reflector 40b so that the reflecting surface 43b of the reflector 40b does not have to be formed at a position unnecessary for the reflection of the radiant heat of the halogen heater 50b. An extending portion (planar portion) 45b extending to the pad 60 side is provided. Thereby, even if the rotation restricting plate 91 is provided in the heat generation region of the halogen heater 50b, the rotation restricting plate 91 is applied to the extending portion 45b instead of the reflecting surface 43b, thereby suppressing a reduction in reflection efficiency due to the reflecting plate 43b. It becomes possible to regulate the rotation of the reflector 40b.

  FIG. 13 is a schematic view of the fixing device 12 in which a gap is provided between the stay 61 and the reflector 40 and the reflector 40 is installed. In the present embodiment, as described above, by attaching the reflector 40 to the halogen heater 50, the apex 41 of the mountain-shaped portion 42 of the reflector 40 and the center of the halogen heater 50 without fixing the reflector 40 to the stay 61. The positional accuracy with O can be maintained. Therefore, as shown in FIG. 13, the reflectors 40a and 40b can be installed by providing a gap between the stay 61 and the reflectors 40a and 40b.

  At this time, the reflector 40a located on the upper side of the stay 61 may rotate toward the stay 61 due to gravity, and the stay 61 and the reflector 40a may come into contact with each other. Therefore, in the fixing device 12 shown in FIG. 13, the stay 61 is provided with a rotation restricting plate 92 for restricting the rotation of the reflector 40 a toward the stay 61 on the surface opposite to the pressure pad 60 side of the stay 61. ing. Further, the reflector 40a is also provided with an extending portion (planar portion) 45a extending from the inclined surface portion of the reflecting surface 43a to the pressure pad 60 side. The extension portion 45a of the reflector 40a and the rotation restricting plate 92 abut against each other, thereby restricting the rotation of the reflector 40a toward the stay 61 and preventing the reflector 40a and the stay 61 from contacting each other. Further, the end of the reflector 40b opposite to the pressure pad side is provided by restricting the rotation of the reflector 40b by applying the extension 45b of the reflector 40b and the rotation restricting plate 91 as shown in FIG. It is possible to prevent the portion from contacting the stay 61.

  Heat transfer from the reflectors 40a and 40b to the stay 61 can be suppressed by providing the gaps between the stay 61 and the reflectors 40a and 40b and installing the reflectors 40a and 40b. Thereby, heat transfer from the stay 61 to the pressure pad 60 is suppressed, and for example, the pressure pad 60 can be more reliably suppressed from being melted by heat. Even when the extending portions 45a and 45b of the reflectors 40a and 40b are in contact with the stay 61 directly or via the rotation restricting plates 91 and 92, the contact amount is small. For this reason, heat transfer such that the pressure pad 60 is melted by heat is not performed from the reflectors 40 a and 40 b to the stay 61. Further, by positioning the extending portions 45a and 45b of the reflectors 40a and 40b in the non-heat generation regions of the halogen heaters 50a and 50b, it is possible to reduce the heat transmitted from the reflectors 40a and 40b to the stay 61.

  FIG. 14 is a schematic configuration diagram of the fixing device 12 including the arc-shaped portion 46 as a shape that reflects the radiant heat toward the direction different from the direction in which the radiant heat is incident on the reflecting surface 43 of the reflector 40. Since the reflector 40 is common to the above-described fixing device 12 provided with the mountain-shaped portion 42 except that the shape of the portion facing the halogen heater 50 is different, only the difference will be described.

  The fixing device 12 illustrated in FIG. 14 includes an arc-shaped portion 46 that protrudes toward the halogen heater 50 at a portion of the reflector 40 that faces the halogen heater 50. In such an outer peripheral surface of the arc-shaped portion 46, the portion perpendicular to the incident direction of the radiant heat is a very limited range, and the radiant heat incident on the other range is reflected in a direction different from the incident direction. The Therefore, the radiant heat incident on the reflecting surface 43 can be reflected toward the fixing belt 38 while avoiding the passage of the halogen heater 50.

  Further, as a shape for reflecting the radiant heat toward the direction different from the direction in which the radiant heat is incident on the reflecting surface 43 of the reflector 40, the reflector 40 is recessed with respect to the halogen heater 50 at a portion facing the halogen heater 50. A valley-shaped portion may be used.

What was demonstrated above is an example, and there exists an effect peculiar for every following aspect.
(Aspect A)
A rotating body such as an endless fixing belt 38 that is rotatably provided, a contact member such as a pressure roller 30 that comes into contact with the outer peripheral surface of the rotating body, and an inner side of the rotating body via the rotating body. A nip forming member that contacts the contact member to form a nip portion such as a fixing nip SN, a heating element such as a halogen heater 50 disposed inside the rotating body, and a heating element disposed inside the rotating body, A reflecting member such as a reflector 40 that reflects radiant heat radiated from the heating element toward the nip forming member on a reflecting surface such as the reflecting surface 43, and the nip forming member slides on the inner peripheral surface of the rotating body. A rubbing portion such as a pressure pad 60 to be rubbed; and a reinforcing portion such as a stay 61 standing from the rubbing portion toward the inside of the rotating body, wherein the heating element is a portion where the reinforcing portion stands. Opposite the side of The reflecting member is arranged in a reflective shape such as a mountain-shaped portion 42 that reflects radiant heat radiated from the heating element in a direction not facing the heating element at a position facing the heating element on the reflection surface. The fixing device includes a reflection member attaching means such as a fitting portion 44 and a lever portion 51 for attaching the reflection member to the heating element independently of the reinforcing portion.
In (Aspect A), the reflecting member is attached to the heating element independently of the reinforcing portion of the nip forming member by the reflecting member attaching means. That is, the reflecting member is not supported by the nip forming member. Therefore, even if the reinforcing part of the nip forming member is bent toward the inside of the rotating body due to the contact pressure with the contact member, the reflecting member does not deform following the bending. For this reason, it is possible to prevent the positional relationship between the reflective shape of the reflective member and the heating element from deviating due to the reinforcement of the nip forming member being bent, and to maintain the positional relationship. Even if the reinforcing portion of the nip forming member is bent, by maintaining the positional relationship between the reflection shape of the reflection member and the heating element, it is possible to maintain the operation of efficiently heating the fixing belt by the reflection shape of the reflection member. it can.
(Aspect B)
In (Aspect A), the reflection shape is a convex portion protruding from the reflection surface toward the heating element, and the reflection member mounting means is configured such that the reflection member is between the heating element and the reinforcing portion. The reflective member is attached to the heating element so that the central point of the heating element is positioned on an extension line of the reflection surface in the protruding direction of the convex portion. According to this, as described in the above embodiment, the radiant heat incident on the reflecting surface can be reflected toward the rotating body while avoiding the passage of the heating element, and the radiant heat can be prevented from heating the heating element itself.
(Aspect C)
In (Aspect A) or (Aspect B), the reflection shape is a mountain shape protruding from the reflection surface toward the heating element. According to this, as described in the above embodiment, the radiant heat incident on the reflecting surface at a position facing the heating element is incident on the mountain-shaped slope and is reflected toward a direction different from the incident direction. As a result, it is possible to realize a configuration in which the reflected radiant heat enters the rotating body while avoiding passing through the heating element.
(Aspect D)
In (Aspect A) or (Aspect B), the reflection shape is an arc shape protruding from the reflection surface toward the heating element. According to this, as described in the above embodiment, the radiant heat incident on the reflecting surface in the vicinity of the position facing the heating element is incident on the arc-shaped surface and reflected in a direction different from the incident direction. . As a result, it is possible to realize a configuration in which the reflected radiant heat enters the rotating body while avoiding passing through the heating element.
(Aspect E)
In any one of (Aspect A) to (Aspect D), the reflection member attaching means includes a fitting portion such as a fitting portion 44 provided at each longitudinal end of the reflecting member, and each fitting portion. And fitted portions such as insulator portions 51 provided at both ends in the longitudinal direction of the heating element, and the fitting in a state in which the reflecting member is rotatable with respect to the heating element. Part and the said to-be-fitted part fit. According to this, as described in the above embodiment, the positional relationship between the reflecting shape of the reflecting member and the heating element can be always kept in a consistent state.
(Aspect F)
In (Aspect E), the fitting state and the fitting release state of the fitting portion and the fitted portion can be switched by changing the posture of the fitted portion with respect to the fitting portion. According to this, as explained about the above-mentioned embodiment, it can control that a fitting part and a to-be-fitted part remove unintentionally.
(Aspect G)
In any one of (Aspect A) to (Aspect D), the reflection member attachment means is made of a material having higher rigidity than the reflection plate, and is rotatably attached to the heating element to hold the reflection member. A holding member such as the holder 90 is included. According to this, as described in the above embodiment, the deformation of the reflecting member at the time of assembly can be suppressed, and the positional relationship between the reflecting shape of the reflecting member and the heating element can be maintained with high accuracy.
(Aspect H)
In any one of (Aspect E) to (Aspect G), a rotation restricting member such as a rotation restricting plate 91 that restricts the rotation of the reflecting member toward the side approaching the heating element is provided. According to this, as described in the above embodiment, it is possible to prevent the reflecting member from rotating and coming into contact with the heating element.
(Aspect I)
In (Aspect H), the rotation restricting member is located outside the heat generating region of the heat generating element. According to this, as described in the above embodiment, it is possible to suppress a decrease in the reflection efficiency of the reflecting member.
(Aspect J)
In (Aspect I), the reflecting member is provided with an extending portion such as an extending portion 45 that extends from the reflecting surface and contacts the rotation restricting member. According to this, as described in the above embodiment, it is possible to prevent rotation even if a rotation restricting member is provided in the heat generation region.
(Aspect K)
In (Aspect J), the extending portion and the rotation restricting member are located in a heat generating region of the heat generating element. According to this, as described in the above embodiment, an increase in cost can be suppressed.
(Aspect L)
In any one of (Aspect A) to (Aspect K), a gap is provided between the reinforcing portion and the reflective member, and the reflective member is installed. According to this, as described in the above embodiment, heat transfer from the reflecting member to the reinforcing portion is suppressed, heat transfer from the reinforcing portion to the nip forming member is suppressed, and the nip forming member is damaged by heat. Can be suppressed.
(Aspect M)
Toner image forming means for forming a toner image on a recording medium using toner;
In an image forming apparatus including at least a fixing unit such as a fixing device 12 that fixes a toner image on a recording medium to the recording medium by heat, the fixing unit is any one of (Aspect A) to (Aspect L). This fixing device is used. According to this, as described in the above embodiment, it is possible to save energy in the entire image forming apparatus by maintaining the belt heating efficiency in the fixing device.

DESCRIPTION OF SYMBOLS 4 Paper feeder 6 Registration roller pair 8 Photosensitive drum 10 Transfer device 12 Fixing device 14 Paper feed tray 16 Paper feed roller 18 Charging roller 20 Mirror 22 Developing device 22a Developing roller 24 Cleaning device 24a Cleaning blade 26 Exposure unit 30 Pressure roller 38 fixing belt 30a metal core 30b elastic layer 30c release layer 40 reflector 40a reflector 40b reflector 41 apex 41a apex 41b apex 42 chevron shaped part 42a chevron shaped part 42b chevron shaped part 43 reflective surface 43a reflective surface 43b reflective surface 44 Fitting part 44a Fitting part 44b Fitting part 45a Extension part 45b Extension part 46 Arc-shaped part 50 Halogen heater 50a Halogen heater 50b Halogen heater 51 Insulator part 51a Insulator part 51b Insulator part 60 Pressure pad 61 Stay 7 a screw 72a screw 81A side plate 81B side plate 82a bracket 82b bracket 90 holder 91 rotation regulating plate 91a projecting portion 92 rotation regulating plate

Japanese Patent No. 4961047

Claims (13)

An endless rotating body provided rotatably,
A contact member in contact with the outer peripheral surface of the rotating body;
A nip forming member disposed inside the rotating body and forming a nip portion by contacting the contact member via the rotating body;
A heating element disposed inside the rotating body;
A reflective member that is disposed inside the rotating body and reflects radiant heat radiated from the heating element toward the nip forming member on a reflective surface;
The nip forming member has a rubbing portion that rubs against an inner peripheral surface of the rotating body, and a reinforcing portion that stands up from the rubbing portion toward the inside of the rotating body,
The heating element is disposed so as to face the side surface of the standing portion of the reinforcing portion,
In the fixing device, the reflecting member has a reflective shape that reflects radiant heat radiated from the heating element in a direction not facing the heating element at a position facing the heating element on the reflection surface.
A fixing device comprising: a reflecting member attaching means for attaching the reflecting member to the heating element independently of the reinforcing portion. The fixing device according to claim 1,
The reflective shape is a convex portion protruding from the reflective surface toward the heating element,
The reflecting member mounting means is configured so that the reflecting member is positioned between the heating element and the reinforcing portion, and a center point of the heating element is positioned on an extension line of the projecting direction of the convex portion of the reflecting surface. A fixing device, wherein the reflecting member is attached to the heating element. The fixing device according to claim 1 or 2,
The fixing device according to claim 1, wherein the reflection shape is a mountain shape protruding from the reflection surface toward the heating element. The fixing device according to claim 1 or 2,
The fixing device according to claim 1, wherein the reflection shape is an arc shape protruding from the reflection surface toward the heating element. In the fixing device according to any one of claims 1 to 4,
The reflection member attaching means includes a fitting portion provided at each longitudinal end portion of the reflecting member, and a fitted portion provided at each longitudinal end portion of the heating element and fitted into each fitting portion. The fixing device is characterized in that the fitting portion and the fitted portion are fitted in a state where the reflecting member is rotatable with respect to the heating element. The fixing device according to claim 5.
The fixing device is capable of switching between a fitting state and a fitting release state between the fitting portion and the fitting portion by changing a posture of the fitting portion with respect to the fitting portion. . In the fixing device according to any one of claims 1 to 4,
The fixing device is characterized in that the reflecting member attaching means is made of a material having rigidity higher than that of the reflecting plate, and has a holding member that is rotatably attached to the heating element and holds the reflecting member. The fixing device according to any one of claims 5 to 7,
A fixing device comprising a rotation restricting member for restricting rotation of the reflecting member toward the side approaching the heating element. The fixing device according to claim 8.
The fixing device according to claim 1, wherein the rotation restricting member is located outside a heat generating region of the heat generating element. The fixing device according to claim 8.
A fixing device, wherein the reflecting member is provided with an extending portion that extends from the reflecting surface and contacts the rotation restricting member. The fixing device according to claim 10.
The fixing device, wherein the extending portion and the rotation restricting member are located in a heat generating region of the heat generating element. The fixing device according to claim 1,
A fixing device, wherein a gap is provided between the reinforcing portion and the reflecting member, and the reflecting member is installed. Toner image forming means for forming a toner image on a recording medium using toner;
In an image forming apparatus comprising: a fixing unit that fixes a toner image on a recording medium to the recording medium by at least heat;
An image forming apparatus using the fixing device according to claim 1 as the fixing unit.

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