JP2017010004A - Fixation device and image formation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixation device 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 and an image formation apparatus having the same.SOLUTION: A fixation device 9 comprises: a fixation belt 38; a pressure roller 30; a pressure pad 60 which contacts the pressure roller 30 via the fixation belt 38 and forms a fixation nip SN; a stay member 61 which stands from the pressure pad 60 toward the inner side of the fixation belt 38; a halogen heater 50 which is arranged so as to face the side surface of a standing portion of the stay member 61; and a reflector 40 which has a mountain shape 43 being the reflection shape in which the angle at the position facing the halogen heater 50 on a reflection surface 40f reflecting the radiation heat changes. The reflector 40 is supported by a support side plate 70 being a different body from the pressure pad 60 and stay member 61.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. 2004-228561 describes a fixing device that includes a nip forming member (pressure pad) 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 (guide portion) that is in sliding contact with the inner periphery of the fixing belt (heating belt), and a plate-shaped reinforcing portion that stands from the rubbing portion toward the inside of the fixing belt. And having. In addition, heating elements (heat sources) are disposed 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 disclosed 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, as a shape which reflects a radiant heat toward the direction different from the direction from which the radiant heat came, it is not restricted to the mountain shape mentioned above. 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 problem, the invention of claim 1 is arranged inside an endless rotating body that is rotatably provided, a contact member that contacts an outer peripheral surface of the rotating body, and an inner side of the rotating body. A nip forming member that forms a nip portion by contacting the contact member via the rotating body, a heating element disposed inside the rotating body, and disposed inside the rotating body, from the heating element to the nip A reflecting member that reflects the radiant heat radiated toward the forming member at a reflecting surface, and the nip forming member rubs against an inner peripheral surface of the rotating body, and the rotation from the rubbing portion. A reinforcing portion that rises toward the inside of the body, the heating element is disposed so as to face a side surface of the rising portion of the reinforcing portion, and the reflective member includes the heating element on the reflective surface. Reflective type with the angle of the surface at the opposite position changing In the fixing device having, the reflecting member, wherein the nip forming member and the reinforcing member is characterized in that supported in the reflective support member separately.

  According to the present invention, in the belt fixing device, even if the nip forming member is bent, there is an excellent effect that the operation of efficiently heating the fixing belt can be maintained by the reflection shape of the reflecting member.

1 is a schematic configuration diagram of a fixing device according to an embodiment. 1 is a schematic configuration diagram of a copier according to an embodiment. FIG. FIG. 4 is a schematic top view of the fixing device according to the embodiment, where (a) is a non-pressure contact and (b) is a pressure contact. FIG. The side view of the fixing device of a modification. The expansion perspective view of the fixing device of a modification. The schematic block diagram of the fixing device which has a circular arc shape in a reflector. FIG. 3 is a schematic configuration diagram of a fixing device having a valley shape on a reflector. FIG. 3 is a schematic configuration diagram of a fixing device having an inclined flat surface portion on a reflector. FIG. Schematic top view of a fixing device of a comparative example, (a) when not pressed, (b) when pressed.

  Hereinafter, an embodiment of an electrophotographic image forming apparatus including a fixing device to which the present invention is applied will be described.

FIG. 2 is a schematic configuration diagram of a copier 500 that is an image forming apparatus according to the present embodiment.
The copier 500 includes an image forming unit 200, a paper feeding unit 400 disposed below the image forming unit 200, and a scanner unit 300 disposed above the image forming unit 200.

  The image forming unit 200 includes four image forming apparatuses 1 (Y, M, C, K) corresponding to the respective colors of yellow (Y), magenta (M), cyan (C), and black (K). Y, M, C, and K attached to the numbers of the respective symbols indicate members for yellow, magenta, cyan, and black (the same applies hereinafter). The four image forming apparatuses 1 (Y, M, C, and K) have substantially the same configuration except that the colors of the toners to be handled are different from each other. Therefore, “Y” indicating the color of the toner to be used will be described below. , “M”, “C”, and “K” are omitted as appropriate.

  The image forming apparatus 1 includes a photosensitive member 3 as an image carrier, a charging device 2 that charges the surface of the photosensitive member 3, a developing device 5 as a developing unit, and a cleaning device 7 that cleans the photosensitive member 3.

  The image forming unit 200 includes a writing unit 100 that writes an electrostatic latent image on the photoconductor 3, an intermediate transfer belt 16 to which a toner image formed on the photoconductor 3 is transferred, and four photoconductors 3. Four primary transfer rollers 6 that primarily transfer the toner images to the intermediate transfer belt 16 are provided. Further, a secondary transfer nip is formed so as to face the intermediate transfer belt 16 and a toner image on the intermediate transfer belt 16 is transferred to a transfer sheet S as a recording material. A registration roller pair 12 for temporarily waiting for the transfer sheet S is provided upstream of the secondary transfer nip in the transport direction of the transfer sheet S.

  The image forming unit 200 includes four toner bottles 20 (Y, M, C, and K) that store supply toner to be supplied to the developing devices 5 (Y, M, C, and K) that consume toner. A fixing device 9 as a fixing unit is provided above the secondary transfer roller 26, and a discharge roller 18 is provided on the downstream side of the fixing device 9 in the transport direction of the transfer paper S.

  The paper feed unit 400 includes a paper feed cassette 10 that is a recording material storage unit and a paper feed roller 11, and the paper feed cassette 10 stacks transfer sheets S on a stacking surface. The paper feed roller 11 is for separating and feeding the transfer paper S stacked on the paper feed cassette 10 one by one.

  The scanner unit 300 includes a contact glass 31 on which a document is placed. Further, in order to read and scan a document placed on the contact glass 31, a first traveling body 32 including a document illumination light source 32a and a first mirror 32b, a second mirror 35a, and a third mirror 35b are provided. A second traveling body 35 provided. Furthermore, a lens 33 and a CCD (CCD image sensor) 34 installed behind the lens 33 are provided.

Next, an image forming operation of the copying machine 500 will be described.
When an original is placed on the contact glass 31 and an image forming operation is started, the original illumination light source 32a emits light, and the reflected light reflected by the original is reflected by the first mirror 32b, the second mirror 35a, and the third mirror. The light is reflected by the mirror 35 b, imaged by the lens 33, and enters the CCD 34. The scanner unit 300 generates image information to be formed on the transfer paper S based on the light incident on the CCD 34.

  In the image forming unit 200, the rotating photosensitive member 3 is uniformly charged by the charging device 2, and the writing unit 100 is driven based on the image information described above. The writing unit 100 emits irradiation light based on image information from a light source, and scans the surface of the uniformly charged photoreceptor 3 to form an electrostatic latent image on the photoreceptor 3. The electrostatic latent image is developed by supplying a developer (toner) from the developing roller 15 of the developing device 5, and becomes a toner image as a visible image.

  On the other hand, while the toner image is being formed on the photosensitive member 3, the transfer paper S is pulled out from the selected one of the plurality of paper feed cassettes 10 by the paper feed roller 11, and the leading end of the transfer paper S is registered. It waits in the state contact | abutted to the nip part of the roller pair 12. FIG. Then, the registration roller pair 12 starts to rotate at the timing when the transfer paper S is superimposed on the toner image on the intermediate transfer belt 16 onto which the toner images of the respective colors are transferred in the four primary transfer nips. The paper S is sent out to the secondary transfer nip. The transfer sheet S on which the toner image is transferred at the secondary transfer nip is neutralized by contact with the neutralizing brush, mechanically separated from the intermediate transfer belt 16, and then sent to the fixing device 9.

In the fixing device 9, the transfer paper S is heated and pressurized to fix the toner image on the transfer paper S. The transfer sheet S on which the toner image is fixed by passing through the fixing device 9 is discharged onto the discharge tray 8 by the discharge roller 18.
Transfer residual toner remaining on the surface of the photoreceptor 3 after passing through the primary transfer nip is removed from the photoreceptor 3 by the cleaning device 7 and collected. The surface of the photoreceptor 3 from which the transfer residual toner has been collected is neutralized by a neutralization device, and prepared for the next image forming process.

  In the above description, the image forming operation for reading the image information of the document by the scanner unit 300 and forming an image based on the image information has been described. The copying machine 500 can also create an image based on image information input from an external electronic device such as a personal computer.

  In the copying machine 500 that is the image forming apparatus of the embodiment, the toner image on the photosensitive member 3 is an intermediate transfer method in which the toner image is transferred onto the transfer sheet S via the intermediate transfer belt 16 that is an intermediate transfer member. The method for transferring the toner image to the transfer paper S is not limited to the intermediate transfer method, and may be a direct method for transferring the toner image directly from the photosensitive member to the transfer paper S.

FIG. 1 is a schematic configuration diagram of a fixing device 9 according to the present embodiment.
The fixing device 9 includes a pressure roller 30 that is a contact member that is rotationally driven, and a fixing belt 38 that is a substantially cylindrical fixing member. Inside the cylindrical fixing belt 38, a pressure pad 60 and a stay member 61 constituting a nip forming member, and a first halogen heater 50a and a second halogen heater 50b as a plurality of heating elements are provided. Yes.

As shown in FIG. 1, the first halogen heater 50 a and the second halogen heater 50 b are arranged on both sides in the vertical direction with the stay member 61 interposed therebetween.
Further, between the two halogen heaters 50 and the stay member 61, a reflector 40 that reflects the radiant heat radiated from the halogen heaters 50 toward the inner peripheral surface of the fixing belt 38 is disposed.
Further, both ends of the fixing device 9 in the longitudinal direction (the direction orthogonal to the paper surface in FIG. 1) are parts of the structure of the copying machine 500 and support the above-described components of the fixing device 9. A side plate 70 is provided.

The fixing belt 38 is a flexible heating-deformable cylindrical heating rotator, a nickel (Ni) base having a cylindrical outer shape of 30 [mm] and a thickness of 10 to 70 [μm], and the base And an elastic layer coated on the surface. The elastic layer is made of silicone rubber and has a thickness of 50 to 150 [μm].
A release layer having a thickness of 5 to 50 [μm] made of a fluororesin is formed on the outermost layer of the fixing belt 38 in order to enhance durability and secure release properties. Examples of the fluororesin include, but are not limited to, PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymerization) and PTFE (polytetrafluoroethylene).
The fixing belt substrate is not limited to nickel, and may be a metal substrate such as SUS (stainless steel) or a heat resistant resin such as PI (polyimide).

The pressure roller 30 has an outer diameter of 30 [mm], and is formed of a hollow iron core 30a, and an elastic layer 30b and a release layer 30c formed on the surface of the iron core 30a.
The elastic layer 30b is formed 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 toward the fixing belt 38 by the urging means, and the pressure roller 30 and the fixing belt 38 are pressed against each other.

The pressure pad 60 is covered with a resin part 60a made of a resin material having high heat resistance such as LCP (liquid crystal polymer) and the resin part 60a so as to be in sliding contact with the inner surface of the fixing belt 38, and the temperature in the longitudinal direction of the fixing belt 38. And a soaking part 60b made of copper for uniforming the distribution. The pressure pad 60 is pressed against the pressure roller 30 with the fixing belt 38 interposed therebetween to form a fixing nip SN.
The pressure pad 60 is supported by a stay member 61. Both end portions of the stay member 61 in the longitudinal direction are supported by the support side plates 70, and the stay member 61, which is a reinforcing member that reinforces the pressure pad 60 from the inside, receives the pressing force of the pressure roller 30 against the pressure pad 60. A fixing nip SN is formed.

The two halogen heaters 50 (a, b) are arranged on both sides in the vertical direction with the stay member 61 interposed therebetween, and both ends in the longitudinal direction are supported by heater folders located on the outer side in the longitudinal direction than the support side plate 70.
In the first halogen heater 50a, the first light emitting portion filament 51a is arranged in the longitudinal direction in a narrow region corresponding to the width of the small size transfer paper S. In the second halogen heater 50b, the second light emitting unit filament 51b is arranged in the longitudinal direction in a region outside the width of the small transfer sheet S in the wide region corresponding to the width of the large transfer sheet S.

  The reflector 40 is disposed at a position where the halogen heater 50 and the stay member 61 face each other, and both longitudinal ends thereof are supported by the support side plates 70. The reflector 40 is formed of an aluminum substrate and a silver paste applied to the surface of the substrate, and reflects the radiant heat of the halogen heater 50 toward the fixing belt 38 by the reflection surface 40f. The reflector 40 has a shape in which a plate-like member is bent a plurality of times so as to block between the stay member 61 and the pressure pad 60 and the halogen heater 50. By adopting such a bent shape, the reflector 40 has a configuration in which the angle of the surface of the reflecting surface 40f at the position facing the halogen heater 50 is changed.

  Further, at the position where the perpendicular line dropped from the center of the halogen heater 50 to the reflecting surface 40 f of the reflector 40 and the reflecting surface 40 f intersect, a mountain shape 43 having the apex 41 as this position is formed. By providing such a mountain shape 43, of the radiant heat irradiated from the halogen heater 50, the radiant heat incident on the reflecting surface 40 f along the perpendicular line enters the slope of the mountain shape 43. At this time, since the incident direction of the radiant heat and the slope of the mountain shape 43 are not perpendicular, the radiant heat is reflected in a direction different from the incident direction. Therefore, the radiant heat incident on the reflecting surface 40f can be reflected toward the fixing belt 38 while avoiding the passage of the halogen heater 50, and the radiant heat can be prevented from heating the halogen heater 50 itself.

Here, a conventional fixing device will be described.
In an image forming apparatus such as a copying machine, a printer, or a facsimile, a toner image is formed on an image carrier based on image information, and the toner image is transferred onto a recording material such as paper or an OHP sheet to carry the toner image. The recorded material is passed through a fixing device, and the toner image is fixed on the recording material by heat and pressure.
The fixing device is expected to shorten the waiting time (warm-up time) by instantaneously heating the heating member from the viewpoint of saving energy and preventing the user from waiting when using the image forming apparatus. It is rare. As a fixing device for realizing energy saving and shortening of waiting time, a technique for directly heating a thin belt and a film or a thin roller with a halogen heater has been proposed.

  The fixing device described in Patent Document 1 uses an endless fixing belt having a heat capacity lower than that of the heating roller, and includes a pressure pad and its reinforcing member inside the fixing belt. This realizes a fixing device that shortens. Further, as the size of the image forming apparatus is reduced, the diameter of the fixing belt is reduced, and the distance between the reinforcing member or the reflecting member inside the fixing belt and the heating element is shortened. When the distance between the reflecting member and the heating element is short, the amount of radiant heat reflected by the reflecting member passes through the heating element increases, and the heating efficiency for the fixing belt decreases.

  If the thickness of the reflecting member is reduced in order to ensure the necessary distance between the heating element and the reflecting member, the rigidity is reduced as a result of the reduction, and the reflecting member may be bent by its own weight in the longitudinal direction. As a configuration for preventing the occurrence of such bending, a configuration in which the reflecting member is completely fixed or integrally formed with the reinforcing member is conceivable.

Further, by disposing a reinforcing member between a plurality of halogen heaters existing inside the fixing belt, heating of the halogen heaters can be prevented. Furthermore, the position facing the halogen heater on the reflecting surface of the reflecting member attached to the reinforcing member, that is, the position where the perpendicular line extending from the center of the halogen heater to the reflecting surface intersects the reflecting surface is a mountain shape. This eliminates substantially perpendicular incidence from the halogen heater to the reflecting member, prevents the radiant heat from being reflected by the reflecting member and heating the halogen heater itself, and heats the fixing belt with the reflected radiant heat.
In such a fixing device, the position where the perpendicular intersects the reflecting surface and the position of the apex of the mountain shape are accurately matched to eliminate the substantially perpendicular incidence to the reflecting member, and the radiant heat heats the halogen heater itself. It is important to prevent this from happening.

  In the configuration including the endless fixing belt having a low heat capacity and the pressure pad and the reinforcing member inside the fixing belt as described above, the pressure roller and the pressure pad existing outside the fixing belt are in pressure contact with each other. A fixing nip is formed. At this time, pressure in the press contact direction is applied to the entire longitudinal direction of the pressure pad and the reinforcing member, and bending occurs in the longitudinal direction. In the configuration in which the reflecting member is attached to the reinforcing member, the reflecting member follows the bending of the reinforcing member due to the applied pressure, the position of the apex of the reflecting member mountain shape and the center of the halogen heater is shifted, and the heating efficiency improvement effect of the fixing belt Can no longer be obtained.

  This bending can be prevented by increasing the rigidity of the reinforcing member in a large size. However, since the reinforcing member needs to be stored inside the fixing belt, it is difficult to increase the size. For this reason, it is common to allow some bending and determine the shape of the pressure pad and the reinforcing member in consideration of the bending.

FIG. 11 is a perspective explanatory view of a fixing device 9 of a comparative example different from the fixing device 9 of the embodiment described above in that the reflector 40 is fixed to the stay member 61 instead of the support side plate 70. FIG. 11 shows a state in which the fixing belt 38 is removed, and only the track of the fixing belt 38 is indicated by a broken line for convenience.
FIG. 12 is a top schematic view schematically showing the fixing device 9 of the comparative example as viewed from above. 12A shows a non-pressing state in which the pressure roller 30 is not urged toward the fixing belt 38, and FIG. 12B urges the pressure roller 30 toward the fixing belt 38. Indicates the time of pressure contact.

  The comparative example is a configuration in which the reflector 40 is supported by the stay member 61, and the reflector 40 is fixed to both ends in the longitudinal direction of the stay member 61 with fixing screws 42. Then, as shown in FIG. 12A, the position of the apex 41 of the mountain shape 43 of the reflector 40 and the first halogen heater in the lateral direction of the apparatus (direction parallel to the X axis in the figure) during non-pressure welding It coincides with the position of the center of 50a.

  At the time of press contact, the pressure roller 30 is urged toward the fixing belt 38, and pressure is applied to the stay member 61 via the fixing belt 38 and the pressure pad 60. When a pressing force is applied to the stay member 61, the stay member 61 is deformed such that the longitudinal center portion thereof is separated from the pressure roller 30 as shown in FIG.

At this time, the reflector 40 is deformed following the stay member 61, and the vertex 41 of the above-described mountain shape 43 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 41 of the mountain-shaped shape 43 of the reflector 40 and the position of the center of the first halogen heater 50a greatly deviate occurs in the lateral direction of the apparatus. As a result, the incident radiant heat cannot be reflected to the fixing belt 38 while avoiding the passage of the first halogen heater 50a, and the belt heating efficiency is lowered.
In the description of the comparative example described above, the first halogen heater 50a has been described. However, the same problem occurs with the second halogen heater 50b located on the opposite side with the stay member 61 interposed therebetween.

FIG. 3 is an explanatory perspective view of the fixing device 9 according to the embodiment. FIG. 3 shows a state in which the fixing belt 38 is removed.
FIG. 4 is a schematic top view schematically showing the fixing device 9 according to the embodiment as viewed from above. 4A shows a non-pressing state in which the pressure roller 30 is not urged toward the fixing belt 38, and FIG. 4B urges the pressure roller 30 toward the fixing belt 38. FIG. Indicates the time of pressure contact.

  The fixing device 9 according to the embodiment has a configuration in which the reflector 40 is supported by the support side plate 70. The reflector 40 is fixed to the support side plate 70 by inserting 5 to 8 [mm] at both longitudinal ends of the reflector 40 into the two support side plates 70 (the back side support side plate 70a and the front side support side plate 70b). . As shown in FIG. 4A, at the time of non-pressure welding, the position of the vertex 41 of the mountain shape 43 of the reflector 40 and the position of the center of the first halogen heater 50a coincide with each other in the lateral direction of the apparatus. .

  The stay member 61 is also fixed to the support side plate 70, and 5 to 8 [mm] at both ends in the longitudinal direction of the stay member 61 is inserted at a position 1 [mm] below the insertion portion of the reflector 40 in the support side plate 70. To be fixed.

  At the time of press contact, the pressure roller 30 is urged toward the fixing belt 38, and pressure is applied to the stay member 61 via the fixing belt 38 and the pressure pad 60. When a pressing force is applied to the stay member 61, the stay member 61 is deformed such that the central portion in the longitudinal direction is separated from the pressure roller 30, as shown in FIG.

  In the fixing device 9 of the embodiment, the reflector 40 is not fixed to the stay member 61 but is supported by the two support side plates 70 (a, b), and therefore follows the deformation of the pressure pad 60 and the stay member 61. do not do. For this reason, even at the time of non-pressure welding, a position shift between the position of the apex 41 of the mountain shape 43 of the reflector 40 and the position of the center of the first halogen heater 50a does not occur in the lateral direction of the apparatus. That is, the positional accuracy between the center position of the first halogen heater 50a and the position of the apex 41 of the mountain shape 43 can be maintained.

As a result, the incidence of substantially vertical radiant heat on the reflector 40 is eliminated, and it is possible to maintain the state in which the radiant heat incident on the reflector 40 can be reflected to the fixing belt 38 while avoiding the passage of the first halogen heater 50a. be able to.
Further, by maintaining the belt heating efficiency in the fixing device 9, the power consumption in the entire copying machine 500 can be reduced, and energy saving can be achieved.

Further, by fixing the stay member 61 to the support side plate 70, it is possible to prevent the reflector 40 from being deformed by bending of the stay member 61 while suppressing an increase in the number of parts.
As shown in FIG. 1, heating of the halogen heaters 50 can be prevented by arranging the stay member 61 and the reflector 40 between the plurality of halogen heaters 50.

[Modification]
Next, a modification of the fixing device 9 according to this embodiment will be described.
FIG. 5 is an explanatory perspective view of the fixing device 9 according to the modification, FIG. 6 is a side view of the fixing device 9 according to the modification, and FIG. 7 is an enlarged view of the fixing device 9 according to the modification from an angle different from FIG. FIG.
5 to 7 show a state in which the fixing belt 38, the second halogen heater 50b, and the reflector 40 facing the second halogen heater 50b are removed.

As shown in FIG. 5, the fixing device 9 according to the modification has a configuration in which the stay member 61, the reflector 40, and the halogen heater 50 are simultaneously supported by the support side plate 70.
As shown in FIG. 5, the support side plate 70 is formed with a pentagonal heater support opening 71 into which the halogen heater 50 is inserted. Then, as shown in FIG. 6, the halogen heater 50 placed on the two planes forming the mountain shape protruding downward in the pentagonal shape of the heater support opening 71 is held from above by the heater fixing member 73. Thus, the halogen heater 50 is fixed in contact with a total of three points, that is, the contact portion with the two planes and the contact portion with the heater fixing member 73.

  And the peak-shaped peak protruding below the heater support opening 71, and the portion corresponding to the peak 41 of the peak-shaped 43 of the reflector 40 in the opening provided in the support side plate 70 for inserting the reflector 40, The positions in the horizontal direction of the device are matched. Thereby, the positioning of the center of the halogen heater 50 and the apex 41 of the mountain shape 43 of the reflector 40 can be performed with high accuracy.

Next, the configuration of the reflector 40 and the leaf spring 72 that applies tension to the reflector 40 will be described with reference to FIG.
One end of the leaf spring 72 is press-fitted and fixed to the support side plate 70, and the other end is inserted into the reflector 40 and bent into an approximately “L” shape. In the natural state, the leaf spring 72 has a shape that extends outward in the longitudinal direction rather than a right angle as indicated by “72a” in FIG. 7, and the other end is press-fitted into the reflector 40 in a state of being bent at a substantially right angle. To do. Thereby, a force that the leaf spring 72 tries to return to the natural state acts on the reflector 40. 5 to 7 show a state in which the leaf spring 72 is inserted into the front side support side plate 70b. Similarly, the leaf spring 72 is also inserted into the back side support side plate 70a in a state bent substantially at a right angle. Thereby, the force which the two leaf | plate springs 72 return to a natural state acts so that the reflector 40 may be pulled in a longitudinal direction, and it prevents that bending arises about a longitudinal direction by the dead weight of the reflector 40.

8 and 9 are schematic configurations of the fixing device 9 having a shape other than the mountain shape 43 as a shape for reflecting the radiant heat toward a direction different from the direction in which the radiant heat is incident on the reflecting surface 40f of the reflector 40. FIG. FIG.
Since the reflector 40 is common except that the shape of the portion facing the halogen heater 50 is different, only the difference will be described.

  The fixing device 9 shown in FIG. 8 includes an arc shape 44 that protrudes toward the halogen heater 50 at a portion of the reflector 40 that faces the halogen heater 50. On the outer peripheral surface of such an arc shape 44, the portion perpendicular to the incident direction of the radiant heat is in a very limited range, and the radiant heat incident on the other range is reflected in a direction different from the incident direction. . Therefore, similarly to the fixing device 9 of the above-described embodiment, the radiant heat incident on the reflecting surface 40 f can be reflected toward the fixing belt 38 while avoiding the passage of the halogen heater 50.

  The fixing device 9 shown in FIG. 9 includes a valley shape 45 that is recessed with respect to the halogen heater 50 at a portion facing the halogen heater 50 in the reflector 40. Since the inclined surface forming such a valley shape 45 is not perpendicular to the incident direction of the radiant heat, the radiant heat is reflected in a direction different from the incident direction. Therefore, similarly to the fixing device 9 of the above-described embodiment, the radiant heat incident on the reflecting surface 40 f can be reflected toward the fixing belt 38 while avoiding the passage of the halogen heater 50. In the case of the configuration including the valley shape 45 shown in FIG. 9, if the two slopes of the valley shape 45 are perpendicular to each other, the radiant heat may be reflected toward the incident direction. It is desirable that the arrangement is not perpendicular.

FIG. 10 shows that the reflection surface 40f of the reflector 40 connects two plane portions that are parallel and different in level to reflect the radiation heat in a direction different from the direction in which the radiant heat is incident. 3 is a schematic configuration diagram of a fixing device 9 having an inclined flat surface portion. FIG.
Since the configuration of the reflector 40 is the same as that of the fixing device 9 shown in FIG. 1 except that the shape of the reflector 40 is different, only the differences will be described.

  In the fixing device 9 shown in FIG. 10, the two reflectors 40 are arranged so as to cover the standing portion of the stay member 61 that stands and supports the pressure pad 60. As shown in FIG. 10, the reflector 40 includes two first and second reflection plane portions 46 </ b> A and 46 </ b> C, which are two parallel and different plane portions, and the first reflection plane portion 46 </ b> A and the third reflection plane. It is formed by a second reflection plane part 46B which is an inclined plane part connecting the part 46C.

  The two halogen heaters 50 (50a, 50b) are respectively positioned at positions facing the second reflection plane part 46B, and the incident angle of the radiant heat incident on the second reflection plane part 46B is not perpendicular to the inclined surface. . For this reason, in the 2nd reflective plane part 46B, a radiant heat is reflected toward the direction different from the direction from which the radiant heat came, and it can suppress that the radiant heat reflected in the 2nd reflective plane part 46B goes to the halogen heater 50. Therefore, as indicated by an arrow “H” in FIG. 10, the radiant heat from the halogen heater 50 that has entered the second reflection flat surface portion 46 </ b> B does not return to the halogen heater 50 and is fixed on the side opposite to the pressure pad 60. Reflected toward the belt 38. Therefore, the fixing belt 38 can be efficiently heated by preventing the radiant heat from heating the halogen heater 50 itself (a glass tube or the like constituting the halogen heater 50).

  The copier 500 according to the present embodiment is a vertical conveyance type image forming apparatus that conveys a sheet from below to above. For this reason, the fixing device 9 has a configuration in which the fixing belt 38 and the pressure roller 30 are arranged in the horizontal direction. The image forming apparatus may be of a lateral conveyance type that conveys paper in the horizontal direction. In this case, as the fixing apparatus, a fixing belt and a pressure roller are arranged in the vertical direction, and the fixing apparatus of the above-described embodiment. A structure in which 9 is rotated by 90 [°] can be used.

  What was demonstrated above is an example, and there exists an effect peculiar for every following aspect.

(Aspect A)
A rotating member such as an endless fixing belt 38 provided rotatably, a contact member such as a pressure roller 30 that contacts the outer peripheral surface of the rotating member, and a contact member disposed inside the rotating member via the rotating member. A nip forming member such as a pressure pad 60 and a stay member 61 that 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 an inner side of the rotating body. And a reflecting member such as a reflector 40 that reflects the radiant heat radiated from the heating element toward the nip forming member with a reflecting surface such as the reflecting surface 40f. The nip forming member slides on the inner peripheral surface of the rotating body. The heat generating body has a rubbing portion such as a pressure pad 60 to be rubbed, and a reinforcing portion such as a stay member 61 standing from the rubbing portion toward the inside of the rotating body. The reflective member is arranged so as to face the A fixing device 9 having a reflective shape in which the angle of the surface is changed, such as a mountain shape 43 that reflects radiant heat radiated from the heat generating member in a direction not facing the heat generating member, at a position facing the heat generating member on the projecting surface. In this fixing device, the reflective member is supported by a reflective support member such as a support side plate 70 that is separate from the nip forming member.
According to this, as described in the above embodiment, the reflecting member is supported by the reflecting support member separate from the nip forming member, thereby fixing the reflecting member independently of the reinforcing portion of the nip forming member. It becomes possible. Therefore, even if the nip forming member bends toward the inside of the rotating body due to the contact pressure with the contact member, it is possible to realize a configuration in which 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 bending of the nip forming member, and to maintain the positional relationship. Even if the nip forming member bends, 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.

(Aspect B)
In the aspect A, the reflection shape is a convex portion such as a mountain shape 43 or an arc shape 44 protruding from the reflection surface such as the reflection surface 40f toward the heating element such as the halogen heater 50, and the reflection support of the support side plate 70 or the like. The reflective member is fixed so that the reflective member is located between the heat generating element and the reinforcing portion such as the stay member 61, and the center point of the heat generating element is positioned on the extension line in the protruding direction of the convex portion of the reflecting surface. To do.
According to this, as described in the above embodiment, the radiant heat incident on the reflecting surface can be reflected toward the rotating body such as the fixing belt 38 while avoiding the passage of the heat generating body, and the radiant heat heats the heat generating body itself. Can be prevented.

(Aspect C)
In either aspect A or B, the reflection shape is a mountain shape such as a mountain shape 43 that protrudes from a reflection surface such as the reflection surface 40 f toward a heating element such as the halogen heater 50.
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 is incident on a rotating body such as the fixing belt 38 while avoiding passing through the heating element.

(Aspect D)
In either aspect A or B, the reflection shape is an arc shape such as an arc shape 44 projecting from a reflection surface such as the reflection surface 40f toward a heating element such as the halogen heater 50.
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 is incident on a rotating body such as the fixing belt 38 while avoiding passing through the heating element.

(Aspect E)
In any of the aspects A and B, the reflecting member such as the reflector 40 has two flat portions (the first reflecting flat surface portion 46A and the third reflecting portion 46A) that are parallel to and different from the portion where the reinforcing member such as the stay member 61 stands. The reflection shape is an inclined plane portion such as a second reflection plane portion 46B that connects the two plane portions.
According to this, as described in the above embodiment, the radiant heat that enters the vicinity of the position facing the heating element on the reflecting surface is incident on the surface of the inclined plane portion that is not a plane perpendicular to the incident direction, Reflects in a direction different from the incident direction. As a result, it is possible to realize a configuration in which the reflected radiant heat is incident on a rotating body such as the fixing belt 38 while avoiding passing through the heating element. Even if the positional relationship between the reflecting member and the heating element is deviated, the surface of the position where the radiant heat is incident on the reflecting surface is the surface of the inclined plane portion that is not a plane perpendicular to the incident direction of the radiant heat. For this reason, even if the positional relationship between the reflecting member and the heating element is deviated, the radiant heat reflected by the reflecting surface of the reflecting member is returned to the heating source, and the use of the radiant heat for heating the heating source itself can be suppressed. Rotating bodies such as 38 can be efficiently heated.

(Aspect F)
In any one of the aspects A to E, the reflective support member such as the support side plate 70 supports the reinforcing portion such as the stay member 61.
According to this, as described in the above embodiment, the reflective support member also serves as the support member of the reinforcing portion, thereby suppressing the increase in the number of parts, and the reflective portion such as the reflector 40 by bending the reinforcing portion. Can be prevented from being deformed.

(Aspect G)
In any one of the aspects A to F, the reflective support member such as the support side plate 70 supports a heating element such as the halogen heater 50.
According to this, as described in the above modification, the reflection support member also serves as the support member of the heating element, so that the center of the heating element and the reflection shape such as the mountain shape 43 of the reflection member such as the reflector 40 can be obtained. Can be accurately positioned.

(Aspect H)
In any one of the aspects A to G, the reflective support member such as the support side plate 70 is fixed at a position where the reflective member such as the reflector 40 is separated from the reinforcing portion such as the stay member 61 by a predetermined distance such as 1 [mm]. To do.
According to this, as described in the above embodiment, it is possible to prevent the reflecting member from being deformed by bending of the reinforcing portion.

(Aspect I)
In any of the aspects A to H, a leaf spring that applies a tension from the center in the rotation axis direction (longitudinal direction, etc.) of the rotating body such as the fixing belt 38 to the reflecting member such as the reflector 40. Reflecting member pulling means such as 72 is provided.
According to this, as described in the modification, the reflecting member is prevented from being bent due to its own weight.

(Aspect J)
A copier 500 including a toner image forming unit such as an image forming unit 200 that forms a toner image on a recording medium using toner, and a fixing unit that heats and fixes the toner image on a recording medium such as a transfer sheet S. In the image forming apparatus such as the fixing device, a fixing device such as the fixing device 9 according to any one of the aspects A to I is used as the fixing unit.
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 1 Image forming device 2 Charging device 3 Photoconductor 5 Developing device 6 Primary transfer roller 7 Cleaning device 8 Paper discharge tray 9 Fixing device 10 Paper feed cassette 11 Paper feed roller 12 Registration roller pair 15 Development roller 16 Intermediate transfer belt 18 Paper discharge roller 20 Toner bottle 26 Secondary transfer roller 30 Pressure roller 30a Iron core 30b Elastic layer 30c Release layer 32 First traveling body 31 Contact glass 32a Document illumination light source 32b First mirror 33 Lens 34 CCD
35 Second traveling body 35a Second mirror 35b Third mirror 38 Fixing belt 40 Reflector 40f Reflecting surface 41 Apex 42 Fixing screw 43 Mountain shape 44 Arc shape 45 Valley shape 46A First reflecting plane portion 46B Second reflecting plane portion 46C Third reflection flat surface portion 50 Halogen heater 50a First halogen heater 50b Second halogen heater 51a First light emitting portion filament 51b Second light emitting portion filament 60 Pressure pad 60a Resin portion 60b Heat equalizing portion 61 Stay member 70 Support side plate 70a Back side Support side plate 70b Front side support side plate 71 Heater support opening 72 Leaf spring 73 Heater fixing member 100 Writing unit 200 Image forming unit 300 Scanner unit 400 Paper feed unit 500 Copier S Transfer paper SN Fixing nip

Patent 4961047

Claims (10)

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 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 reflection member has a reflection shape in which the angle of the surface of the reflection surface at a position facing the heating element is changed.
The fixing device, wherein the reflection member is supported by a reflection support member separate from the nip forming member. The fixing device according to claim 1,
The reflective shape is a convex portion protruding from the reflective surface toward the heating element,
The reflection support member is positioned such that the reflection member is positioned between the heating element and the reinforcing portion, and the center point of the heating element is positioned on an extension line in the protruding direction of the convex portion of the reflection surface. A fixing device, wherein the reflecting member is fixed. The fixing device according to claim 1,
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,
The fixing device according to claim 1, wherein the reflection shape is an arc shape protruding from the reflection surface toward the heating element. The fixing device according to claim 1,
The reflecting member has two flat portions that are parallel to and uneven with the portion where the reinforcing member stands,
The fixing device according to claim 1, wherein the reflection shape is an inclined flat portion that connects the two flat portions. The fixing device according to claim 1,
The fixing device, wherein the reflection support member supports the reinforcing portion. The fixing device according to claim 1,
The fixing device, wherein the reflective support member supports the heating element. The fixing device according to any one of claims 1 to 7,
The fixing device, wherein the reflection support member fixes the reflection member at a position away from the reinforcing portion by a predetermined distance. The fixing device according to any one of claims 1 to 8,
A fixing device comprising: a reflecting member pulling unit that applies a tension from the center in the rotation axis direction of the rotating body toward the outside of the reflecting member. 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 heats and fixes a toner image on a recording medium,
An image forming apparatus using the fixing device according to claim 1 as the fixing unit.

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