JP2015087640A - Fixing apparatus and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device and an image forming apparatus that can suppress water droplets on a separation member from being adhered to a recording medium, while ensuring the strength of the separation member.SOLUTION: There is provided a fixing device including: two surface moving bodies that form a fixing nip part; heating means for heating at least one of the two surface rotating bodies; and a tabular separation member that is located on the downstream side in a recording medium conveyance direction with respect to the fixing nip part, provided relative to at least one of the two surface moving bodies, and has the tip in contact with or in the proximity of the surface of the surface moving body to separate a recording medium having passed through the fixing nip part from the surface moving body, where the separation member includes a recording medium opposing surface that is arranged opposite to a recording medium to be conveyed, and an opening that penetrates a surface moving body opposing surface arranged opposite to the surface moving body, and further has a first bending wall part that is bent to rise from a side of the opening on the tip side relative to the surface moving body opposing surface.

Description

  The present invention relates to a fixing device used in an image forming apparatus such as a printer, a facsimile machine, and a copying machine, and an image forming apparatus including the fixing device.

  Conventionally, in an image forming apparatus, a latent image on an image carrier is developed with toner supplied from a developing device, and a toner image as a visible image is formed on the image carrier. The toner image on the image carrier is transferred to a sheet as a recording medium by a transfer device and fixed on the sheet by a fixing device.

  As this fixing device, for example, a heater as a heat source is provided inside, and the fixing belt as one surface moving body configured to be rotatable, and the surface of the fixing belt can be rotated by contacting with a predetermined pressure. And a pressure roller as the other surface moving body.

  Then, the toner image on the paper is fixed on the paper by heat and pressure at the fixing nip formed by the fixing belt and the pressure roller. The paper on which the toner image is fixed at the fixing nip is discharged through a paper discharge path.

  On the other hand, in the fixing device, when the toner carried on the paper passes through the fixing nip portion, the toner melts in the fixing nip portion, so that the toner acts as an adhesive, and the paper exiting the fixing nip portion is transferred to the fixing belt. It may wrap around the surface without being separated from the surface. In addition, the paper may be wound around the surface of the fixing belt or the pressure roller without being separated from the surface of the fixing belt or the pressure roller after passing through the fixing nip due to the stiffness of the paper or the curvature of the fixing belt or the pressure roller.

  For this reason, the fixing belt and pressure are separated by a separation plate, which is a plate-shaped separation member provided in the vicinity of the downstream side of the fixing nip portion in the sheet conveyance direction with the leading end in contact with or close to the surface of the fixing belt or pressure roller. Separate the paper from the roller.

  When the separation plate is provided in the vicinity of the fixing belt heated by a heater, a metal plate that is less likely to be deformed or melted even at a high temperature compared to resin, has a low thermal expansion, and can easily provide a distance from the fixing belt with high accuracy. It is known to use what was done.

  However, when the fixing belt is heated from the cold state to the fixing-possible temperature with the power turned off, the separation member that rises slower than the fixing belt and has a relatively low temperature is heated during the fixing process. Condensation may occur due to adhesion of water vapor generated from the printed paper. For this reason, when the sheet conveyed through the fixing nip contacts the separating member on which the condensation has occurred, water droplets adhere to the sheet, causing wrinkles on the sheet or distorting the image.

  The separation plate provided in the fixing device described in Patent Document 1 has a region in which the heat capacity is reduced by forming a recess in a part of the wall surface of the separation plate by cutting and reducing the thickness of a part of the separation plate. A heat capacity reduction region is provided. As a result, the temperature of the sheet passing surface facing the paper transported by the separation plate can be rapidly increased to quickly evaporate water droplets adhering to the separation plate, thereby preventing water droplets from adhering to the paper from the separation plate. ing.

  However, since the heat capacity is not reduced in a portion other than the heat capacity reduction region of the separation plate, it takes time for the temperature to rise, and the evaporation of water droplets is slow, and there is a possibility that the water droplets adhere to the paper.

  Therefore, if the plate thickness of the entire separation plate is made too thin in order to reduce the heat capacity of the entire separation plate, sufficient strength cannot be secured and the separation plate is easily deformed, and the leading edge of the separation plate with respect to the fixing belt The position shifts and the separability decreases.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a fixing device that can prevent water droplets from adhering to the recording medium from the separating member while securing the strength of the separating member, and the fixing device. Is provided.

  In order to achieve the above object, the invention of claim 1 forms a fixing nip portion for fixing an unfixed toner image on the recording medium onto the recording medium while conveying the recording medium, and moves endlessly. Two surface moving bodies configured; heating means for heating at least one of the two surface moving bodies; and a position downstream of the fixing nip portion in the recording medium conveyance direction; A plate-shaped separation member that is provided for at least one and separates the recording medium that has passed through the fixing nip portion from the surface moving body by bringing the tip portion into contact with or close to the surface of the surface moving body. In the fixing device, the separation member passes through a recording medium facing surface facing the recording medium to be conveyed and a surface moving body facing surface facing the surface moving body on the side opposite to the recording medium facing surface. Open Parts are provided, it is characterized in that it has a first bending wall portion which is bent from the front end portion of the sides of the opening to rise to the surface moving body facing surface.

  As described above, according to the present invention, there is an excellent effect that water droplets can be prevented from adhering to the recording medium from the separation member while ensuring the strength of the separation member.

FIG. 6 is an explanatory diagram of a separation operation of a sheet from a fixing belt by a separation plate. 1 is a schematic configuration diagram of an image forming apparatus according to an embodiment. 1 is a schematic configuration diagram of a fixing device. FIG. 3 is a schematic diagram when the fixing device is viewed from above. The perspective view of the separating plate which concerns on embodiment. FIG. 6 is a six-side view of the separation plate of the present embodiment. (A) AA sectional view of Drawing 6 (c), (b) An enlarged drawing of field B of Drawing 7 (a). The 6th page figure of the separation plate of a comparative example. (A) AA sectional drawing of FIG.8 (c), (b) The enlarged view of the area | region B of Fig.9 (a). FIG. 3 is an explanatory diagram of a state where a separation plate receives radiant heat generated from a fixing belt. (A) Explanatory drawing when the tip (separation part) of the separation plate is not made thinner than the other part, (b) Explanatory drawing when the tip (separation part) of the separation plate is made thinner than the other part. (A) The figure which showed the case where there is no rake face which scoops up a sheet | seat in the edge | side facing the bending wall part of an opening part, (b) The case where the rake face which scoops up a sheet | seat is provided in the edge | side facing the bending wall part of an opening part FIG. The perspective view of the separating plate which divided and provided the opening part in the some direction in the separating plate longitudinal direction. The 6th page figure of the separation plate which divided and provided the opening part in the some direction in the separation plate longitudinal direction. (A) AA sectional view of Drawing 14 (c), (b) Enlarged view of field B of Drawing 15 (a). The perspective view of the separation board to which the rib was attached. Explanatory drawing about the separating plate which provided the hole shape for attaching a rib. (A) AA sectional view of Drawing 17 (c), (b) An enlarged drawing of field B of Drawing 18 (a).

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the part which is the same or it corresponds, The duplication description is simplified or abbreviate | omitted suitably.

  FIG. 2 is a schematic configuration diagram of a tandem color printer (hereinafter simply referred to as a printer) which is an image forming apparatus according to the present embodiment. The configuration and operation of the printer will be described.

  In the bottle housing portion 101 at the top of the printer main body 1, four toner bottles 102Y, 102M, 102C, and 102K corresponding to the respective colors (yellow, magenta, cyan, and black) are detachably (replaceable). .

  An intermediate transfer unit 85 having an intermediate transfer belt 78 that is rotatably stretched by a plurality of rollers is disposed below the bottle housing portion 101. Further, image forming portions 4Y, 4M, 4C, and 4K corresponding to the respective colors (yellow, magenta, cyan, and black) are arranged in parallel so as to face the intermediate transfer belt 78 below the intermediate transfer unit 85.

  Photosensitive drums 5Y, 5M, 5C, and 5K are disposed in the image forming units 4Y, 4M, 4C, and 4K, respectively. Further, around each of the photosensitive drums 5Y, 5M, 5C, and 5K, a charging device 75, a developing device 76, a cleaning device 77, a charge removal unit (not shown), and the like are disposed.

  Then, an image forming process (charging process, exposure process, development process, transfer process, cleaning process) is performed on each photoconductor drum 5Y, 5M, 5C, 5K, and each photoconductor drum 5Y, 5M, 5C, An image of each color is formed on 5K.

  The photosensitive drums 5Y, 5M, 5C, and 5K are rotationally driven in a clockwise direction in FIG. 2 by a drive motor (not shown), and the surfaces of the photosensitive drums 5Y, 5M, 5C, and 5K are uniform at the position of the charging device 75. Are charged (charging process).

  Then, the surfaces of the photosensitive drums 5Y, 5M, 5C, and 5K reach the irradiation position of the laser light L emitted from the exposure unit 3, and electrostatic latent images corresponding to the respective colors are formed by exposure scanning at this position. (Exposure process).

  Thereafter, the surfaces of the photosensitive drums 5Y, 5M, 5C, and 5K reach a position facing the developing device 76, and the electrostatic latent image is developed at this position to form toner images of each color (developing process). ).

  The surfaces of the photosensitive drums 5Y, 5M, 5C, and 5K on which the toner images are formed are moved along with the intermediate transfer belt 78 and the primary transfer bias rollers 79Y, 79M, and 79C as the photosensitive drums 5Y, 5M, 5C, and 5K rotate. , 79K. At this position, the toner images on the photosensitive drums 5Y, 5M, 5C, and 5K are transferred onto the intermediate transfer belt 78 (primary transfer process). In this way, a color image is formed on the intermediate transfer belt 78.

  At this time, a small amount of untransferred toner remains on the photosensitive drums 5Y, 5M, 5C, and 5K.

  The surfaces of the photosensitive drums 5Y, 5M, 5C, and 5K that have passed through the primary transfer nip reach positions facing the cleaning device 77 as the photosensitive drums 5Y, 5M, 5C, and 5K rotate. The untransferred toner remaining on the photosensitive drums 5Y, 5M, 5C, and 5K at this position is mechanically collected by the cleaning blade of the cleaning device 77 (cleaning process).

  Finally, the surfaces of the photosensitive drums 5Y, 5M, 5C, and 5K reach a position facing a neutralization unit (not shown), and the residual potential on the photosensitive drums 5Y, 5M, 5C, and 5K is removed at this position. The Thus, a series of image forming processes performed on the photosensitive drums 5Y, 5M, 5C, and 5K is completed.

  Here, the intermediate transfer unit 85 includes an intermediate transfer belt 78, a primary transfer bias roller 79, a secondary transfer backup roller 82, a cleaning backup roller 83, a tension roller 84, an intermediate transfer cleaning device 80, and the like.

  The intermediate transfer belt 78 is rotatably supported by a secondary transfer backup roller 82, a cleaning backup roller 83, and a tension roller 84, and is endless in the direction of the arrow in FIG. Moved.

  The four primary transfer bias rollers 79Y, 79M, 79C, and 79K respectively sandwich the intermediate transfer belt 78 with the photosensitive drums 5Y, 5M, 5C, and 5K to form primary transfer nips. A transfer bias having a polarity opposite to the charging polarity of the toner is applied to the primary transfer bias rollers 79Y, 79M, 79C, and 79K.

  When the intermediate transfer belt 78 rotates in the direction of the arrow in the drawing and sequentially passes through the primary transfer nips of the primary transfer bias rollers 79Y, 79M, 79C, and 79K, the photosensitive drums 5Y, 5M, 5C, and 5K are moved over. The toner images of the respective colors are primarily transferred while being superimposed on the intermediate transfer belt 78.

  Thereafter, the intermediate transfer belt 78 onto which the toner images of the respective colors are transferred in an overlapping manner reaches a position facing the secondary transfer roller 89. At this position, the secondary transfer backup roller 82 sandwiches the intermediate transfer belt 78 between the secondary transfer roller 89 and forms a secondary transfer nip.

  Then, the four color toner images formed on the intermediate transfer belt 78 are transferred onto a sheet P as a recording medium conveyed to the position of the secondary transfer nip. At this time, untransferred toner that has not been transferred to the paper P remains on the intermediate transfer belt 78.

  When the surface of the intermediate transfer belt 78 after passing through the secondary transfer nip reaches the position of the intermediate transfer cleaning device 80, untransferred toner on the intermediate transfer belt 78 is collected at this position. Thus, a series of transfer processes performed on the intermediate transfer belt 78 is completed.

  Here, the sheet P conveyed to the position of the secondary transfer nip is conveyed from the sheet feeding unit 12 disposed in the lower portion of the printer body 1 via the sheet feeding roller 97, the registration roller pair 98, and the like. Is.

  Specifically, a plurality of sheets P, which are recording media such as transfer sheets, are stacked and stored in the sheet feeding unit 12. When the paper feed roller 97 is driven to rotate counterclockwise in FIG. 2, the uppermost paper P is fed toward the gap between the registration roller pair 98.

  The paper P conveyed to the registration roller pair 98 is temporarily stopped at the position of the roller nip of the registration roller pair 98 that has stopped rotating. Then, the registration roller pair 98 is rotationally driven in synchronization with the color image (four-color toner image) on the intermediate transfer belt 78, and the sheet P is conveyed toward the secondary transfer nip.

  The paper P on which the color image has been transferred at the secondary transfer nip position is conveyed to the position of the fixing device 20. At this position, the color image transferred on the surface is fixed on the paper P by the heat and pressure of the fixing belt 21 and the pressure roller 31 which are two surface moving bodies.

  Thereafter, the paper P is discharged out of the apparatus through a pair of paper discharge rollers 99. The paper P discharged out of the apparatus by the paper discharge roller pair 99 is sequentially stacked on the stack unit 100 as an output image. Thus, a series of image forming processes in the printer is completed.

  Next, the configuration and operation of the fixing device 20 provided in the printer main body 1 will be described in detail.

FIG. 3 is a schematic configuration diagram of the fixing device 20.
As shown in FIG. 3, the fixing device 20 includes a fixing belt 21 as a belt-shaped fixing member, a nip forming member 26, a heat transfer member 22, a reinforcing member 23 that is a support member that supports the nip forming member 26, and a fixing device. A heater 25 which is a heating means for heating the belt 21 is provided. Further, a pressure roller 31 as a pressure rotator provided to face the fixing belt 21, a temperature sensor 40, a contact / separation mechanism 50 that contacts and separates the pressure roller 31 from the fixing belt 21, and a fixing belt A separation plate 60 for separating the paper P from the paper 21 is provided.

  The separation plate 60 is not only provided corresponding to the fixing belt 21 but also provided separately from the pressure roller 31 by a separation plate similar to the separation plate 60 provided corresponding to the pressure roller 31. You may comprise so that the paper P may be isolate | separated. That is,

  Here, the fixing belt 21 is a thin and flexible endless belt, and rotates in an arrow direction (counterclockwise direction) in FIG. The fixing belt 21 includes a base material layer, an elastic layer, and a release layer that are sequentially laminated from the inner peripheral surface 21a side that is a surface in sliding contact with the nip forming member 26, and the total thickness is 1 [mm]. The following are set.

  The base material layer of the fixing belt 21 has a layer thickness of 30 [μm] to 100 [μm], and is formed of a metal material such as nickel or stainless steel, or a resin material such as polyimide.

  The elastic layer of the fixing belt 21 has a layer thickness of 100 [μm] to 300 [μm], and is formed of a rubber material such as silicone rubber, foamable silicone rubber, and fluorine rubber. By providing the elastic layer, minute irregularities on the surface of the fixing belt 21 in the fixing nip portion N are not formed, and heat is uniformly transmitted to the toner image T on the paper P, thereby suppressing the generation of a scum skin image.

  The release layer of the fixing belt 21 has a layer thickness of 10 [μm] to 50 [μm]. The release layer is formed of a material such as PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), PTFE (polytetrafluoroethylene), polyimide, polyetherimide, PES (polyether sulfide), or the like. Yes. By providing the release layer, the releasability (peelability) for the toner is ensured.

  The diameter of the fixing belt 21 is set to be 15 [mm] to 120 [mm]. In the present embodiment, the diameter of the fixing belt 21 is set to about 30 [mm].

  A heat transfer member 22, a reinforcing member 23, a heater 25, a nip forming member 26, and the like are fixedly provided on the inner peripheral surface 21 a side (inside the loop) of the fixing belt 21.

  The nip forming member 26 is formed in a concave shape so that the surface on the pressure roller 31 side follows the curvature of the pressure roller 31. Thereby, since the paper P is sent out from the fixing nip portion N so as to follow the curvature of the pressure roller 31, it is possible to suppress a problem that the paper P after the fixing process is not attracted to and separated from the fixing belt 21. Can do.

  In this embodiment, the shape of the nip forming member 26 that forms the fixing nip portion N is formed in a concave shape so as to follow the curvature of the pressure roller 31, but the nip forming member 26 that forms the fixing nip portion N is formed. The shape may be flat.

  That is, the surface of the nip forming member 26 facing the pressure roller 31 can be formed in a planar shape. As a result, the shape of the fixing nip portion N becomes substantially parallel to the image surface of the paper P, and the adhesion between the fixing belt 21 and the paper P is increased, so that the fixing property is improved. Further, since the curvature of the fixing belt 21 at the exit side of the fixing nip portion N is increased, the paper P sent out from the fixing nip portion N can be easily separated from the fixing belt 21.

  FIG. 4 is a schematic view of the fixing device 20 as viewed from above. Both ends in the width direction (both ends in the longitudinal direction) of the nip forming member 26 are fixedly supported on the side plates 43 of the fixing device 20.

  The fixing support of the nip forming member 26 by the side plate 43 is positioned at least in the transport direction of the paper P, and the pressing direction of the pressure roller 31 is preferably positioned with the reinforcing member 23.

  The heat transfer member 22 is a tubular pipe-like member obtained by bending a sheet metal having a thickness of 0.1 [mm] into a substantially C shape so that one end and the other end face each other. The heat transfer member 22 is formed so as to directly face the inner peripheral surface of the fixing belt 21 at a position excluding the fixing nip portion N, and is formed in a concave shape inward at the position of the fixing nip portion N. A recess having an opening in which the nip forming member 26 is disposed is provided.

  Both ends in the width direction of the heat transfer member 22 are fixedly supported by the side plates 43 of the fixing device 20. Further, the heat transfer member 22 is heated by the radiant heat (radiant light) of the heater 25 to heat the fixing belt 21. That is, the heat transfer member 22 is directly heated by the heater 25, and the fixing belt 21 is indirectly heated by the heater 25 through the heat transfer member 22.

  As a material of the heat transfer member 22, a metal heat conductor (a metal having heat conductivity) such as aluminum, iron, stainless steel, or the like can be used. In addition, the heating efficiency of the heat transfer member 22 and the fixing belt 21 can be improved by setting the thickness of the heat transfer member 22 to 0.2 [mm] or less. In the present embodiment, the heat transfer member 22 is formed of a stainless steel plate having a thickness of 0.1 [mm].

  The heater 25 which is a heat source is a halogen heater or a carbon heater, and both ends thereof are fixed to the side plate 43 of the fixing device 20 (see FIG. 4). The heat transfer member 22 is heated by the radiant heat of the heater 25 whose output is controlled by the power supply unit of the printer body 1. Further, the fixing belt 21 is entirely heated by the heat transfer member 22 at a position excluding the fixing nip portion N, and heat is applied to the toner image T on the paper P from the surface of the heated fixing belt 21.

  The output control of the heater 25 is performed based on the detection result of the belt surface temperature by the temperature sensor 40 such as a thermistor facing the surface of the fixing belt 21. By such output control of the heater 25, the temperature of the fixing belt 21 (fixing temperature) can be set to a desired temperature.

  As described above, in the fixing device 20 in the present embodiment, not only a part of the fixing belt 21 is locally heated, but the fixing belt 21 is almost entirely heated in the circumferential direction by the heat transfer member 22. It will be. Therefore, even when the speed of the apparatus is increased, the fixing belt 21 can be sufficiently heated to prevent the occurrence of fixing failure.

  That is, since the fixing belt 21 can be efficiently heated with a relatively simple configuration, the warm-up time and the first print time are shortened, and the size of the apparatus is reduced.

  Here, the gap A between the fixing belt 21 and the heat transfer member 22 at normal temperature (a gap at a position excluding the fixing nip portion N) is greater than 0 [mm] and equal to or less than 1 [mm] (0 [mm] <A ≦ 1 [mm]). As a result, the area where the heat transfer member 22 and the fixing belt 21 are in sliding contact with each other can be prevented, and the problem of accelerated wear of the fixing belt 21 can be suppressed, and the heat transfer member 22 and the fixing belt 21 are too far away from each other. It can suppress that the heating efficiency of this falls.

  Further, since the heat transfer member 22 is provided close to the fixing belt 21, the circular posture of the flexible fixing belt 21 is maintained by the heat transfer member 22 to some extent. Damage can be reduced.

  Further, fluorine grease is applied between the fixing belt 21 and the heat transfer member 22 as a lubricant so that the wear of the fixing belt 21 is reduced even if the heat transfer member 22 and the fixing belt 21 are in sliding contact. Yes.

  In addition, in order to reduce the sliding resistance between the heat transfer member 22 and the fixing belt 21, a material having a low friction coefficient with respect to the fixing belt 21 on the sliding surface of the heat transfer member 22 that is in sliding contact with the inner peripheral surface 21 a of the fixing belt 21. Thus, the heat transfer member 22 may be formed. Further, a surface layer made of a material containing fluorine may be formed on the inner peripheral surface 21 a of the fixing belt 21.

  The reinforcing member 23, which is a support member that supports the nip forming member 26, is for reinforcing and supporting the nip forming member 26 that forms the fixing nip portion N, and is fixed to the inner peripheral surface side of the fixing belt 21. ing.

  Referring to FIG. 4, the reinforcing member 23 is formed so that the length in the width direction (longitudinal direction) is equal to the length in the width direction (longitudinal direction) of the nip forming member 26, and both end portions in the width direction Is fixedly supported on the side plate 43 of the fixing device 20 (see FIG. 4).

  The reinforcing member 23 abuts the pressure roller 31 via the nip forming member 26, the fixing belt 21, and the sliding sheet 28, so that the nip forming member 26 applies the pressure force of the pressure roller 31 in the fixing nip portion N. It is restrained from being greatly deformed.

  In addition, in order to satisfy the function mentioned above, it is preferable to form the reinforcing member 23 with a metal material having high mechanical strength such as stainless steel or iron. In addition, a heat insulating member can be provided on a part or all of the surface of the reinforcing member 23 facing the heater 25, or a BA treatment or a mirror polishing treatment can be performed.

  As a result, heat from the heater 25 toward the reinforcing member 23 (heat for heating the reinforcing member 23) is used for heating the heat transfer member 22, so that the heating efficiency of the fixing belt 21 and the heat transfer member 22 is further improved. Will do.

  Referring to FIG. 3, the pressure roller 31 that contacts the outer peripheral surface of the fixing belt 21 at the position of the fixing nip N has a diameter of about 30 [mm], and has an elastic layer on the hollow cored bar 32. 33 is formed. A heat source such as a halogen heater can be provided inside the hollow cored bar 32.

  The elastic layer 33 of the pressure roller 31 is formed of a material such as foamable silicone rubber, silicone rubber, or fluorine rubber. A thin release layer made of PFA, PTFE, or the like can be provided on the surface layer of the elastic layer 33.

  The pressure roller 31 is pressed against the fixing belt 21 to form a desired fixing nip portion N between both members.

  As shown in FIG. 4, both ends in the width direction of the pressure roller 31 are supported rotatably on the side plates 43 of the fixing device 20 via bearings 42. The pressure roller 31 is provided with a gear 45 that meshes with a drive gear of a drive mechanism (not shown). The pressure roller 31 is driven by a rotational driving force transmitted from the drive gear of the drive mechanism via the gear 45. It is rotationally driven in the arrow direction (clockwise direction) in FIG.

  When the elastic layer 33 of the pressure roller 31 is formed of a sponge-like material such as foamable silicone rubber, the pressure applied to the fixing nip portion N can be reduced. Can be reduced.

  Furthermore, since the heat insulation of the pressure roller 31 is enhanced and the heat of the fixing belt 21 is difficult to move to the pressure roller 31 side, the heating efficiency of the fixing belt 21 is improved.

  In this embodiment, the fixing belt 21 is formed so that the diameter of the fixing belt 21 is equal to the diameter of the pressure roller 31, but the diameter of the fixing belt 21 is smaller than the diameter of the pressure roller 31. You can also In this case, since the curvature of the fixing belt 21 at the fixing nip N is smaller than the curvature of the pressure roller 31, the sheet P sent out from the fixing nip N is easily separated from the fixing belt 21.

  In addition, the diameter of the fixing belt 21 can be formed to be larger than the diameter of the pressure roller 31, but the pressure roller 31 is independent of the relationship between the diameter of the fixing belt 21 and the diameter of the pressure roller 31. The applied pressure is not applied to the heat transfer member 22.

  Here, as shown in FIG. 3, the fixing device 20 in the present embodiment is provided with a contact / separation mechanism 50 that contacts and separates the pressure roller 31 with respect to the fixing belt 21. The pressure lever 51, the eccentric cam 52, the pressure spring 53, and the like.

  The pressure lever 51 is rotatably supported by the side plate 43 of the fixing device 20 around a support shaft 51a provided on one end side of the pressure lever 51. The central portion of the pressure lever 51 is in contact with a bearing 42 that is movably held in a long hole formed in the side plate 43.

  A pressure spring 53 is connected to the other end of the pressure lever 51, and an eccentric cam 52 that can be rotated by a drive motor (not shown) is engaged with a holding plate of the pressure spring 53. . With such a configuration, the rotation of the eccentric cam 52 causes the pressure lever 51 to rotate toward the bearing 42 around the support shaft 51a, and the pressure roller 31 moves in the direction of arrow X in FIG. .

  That is, during the normal fixing process, the eccentric cam 52 is in the rotational direction shown in FIG. 3, and the pressure roller 31 presses the fixing belt 21 to form a desired fixing nip portion N.

  On the other hand, when it is not during the normal fixing process (during jam processing or standby), the eccentric cam 52 rotates 180 degrees from the state shown in FIG. Moves in a direction away from the fixing belt 21, and the force to press the fixing belt 21 is reduced.

  In this way, the fixing nip portion N is depressurized during jamming of the paper P or during standby, thereby facilitating the removal work of the jammed paper P, and the pressure roller 31 is applied for a long time during standby. Plastic deformation due to being pressed is suppressed.

The normal operation of the fixing device 20 configured as described above will be briefly described below.
When the power switch of the printer main body 1 is turned on, power is supplied to the heater 25 from a power source (not shown) provided in the printer main body 1, and the pressure roller 31 starts to rotate in the direction of the arrow in FIG. Is done.

  As the pressure roller 31 rotates in this way, the fixing belt 21 is also driven to rotate in the direction of the arrow in FIG. 3 due to the frictional force generated between the pressure roller 31 and the fixing belt 21.

  Thereafter, the paper P is fed from the paper supply unit 12, and an unfixed color image is transferred onto the paper P at the position of the secondary transfer roller 89.

  The sheet P carrying the toner image T, which is an unfixed image, is conveyed in the direction of arrow A1 in FIG. 3 while being guided by a guide plate (not shown), and is fixed by the fixing belt 21 and the pressure roller 31 that are in a pressure contact state. It is fed into the nip N.

  The sheet P is heated by the fixing belt 21 heated by the heat transfer member 22 that receives heat from the heater 25 and the pressing force between the nip forming member 26 reinforced by the reinforcing member 23 and the pressure roller 31. The toner image T is fixed on the surface of the toner. Thereafter, the paper P sent out from the fixing nip N is conveyed in the direction of the arrow A2.

  At this time, the paper P may stick to the fixing belt due to factors such as the type and state of the paper P, the environmental conditions in which the machine is placed, and the amount of toner attached. In such a case, the sheet P is picked up by the separation plate 60 and separated from the fixing belt and conveyed in the A2 direction. Thus, a series of fixing processes in the fixing device 20 is completed.

  Next, features of the fixing device 20 provided in the printer according to the present embodiment will be described.

  FIG. 5 is a perspective view of the separation plate 60 provided in the fixing device 20 according to the present embodiment. FIG. 6 is a six-side view of the separation plate 60 shown in FIG.

  Specifically, FIG. 6A is a view of the separation plate 60 viewed from the direction of the arrow X2 shown in FIG. FIG. 6B is a view of the separation plate 60 viewed from the direction of the arrow Z1 shown in FIG. FIG. 6C is a view of the separation plate 60 viewed from the direction of the arrow X1 shown in FIG. FIG. 6D is a diagram of the separation plate 60 viewed from the direction of the arrow Z2 illustrated in FIG. FIG. 6E is a view of the separation plate 60 viewed from the direction of the arrow Y2 shown in FIG. FIG. 6F is a view of the separation plate 60 viewed from the direction of the arrow Y1 shown in FIG.

  Moreover, Fig.7 (a) is AA sectional drawing of FIG.6 (c), FIG.7 (b) is an enlarged view of the area | region B of Fig.7 (a).

  FIG. 1 is a diagram for explaining the separation operation of the paper P from the fixing belt 21 by the separation plate 60. In FIG. 1, the illustration of components such as the heater 25 and the pressure roller 31 positioned inside the fixing belt 21 is omitted.

  The separation plate 60 is rotatable by fitting a rotation shaft hole 60 a of the separation plate 60 into a rotation shaft (not shown) provided in the frame of the fixing device 20.

  The leading end 60c, which is the upstream end of the separating plate 60 in the sheet passing direction and has a function of separating the paper P from the fixing belt 21, has a clearance of less than 1 [mm] from the surface of the fixing belt 21. Hold and face each other.

  Positioning surfaces 60 b that are positioning portions for positioning the separating plate 60 with respect to the fixing belt 21 are provided at both ends in the longitudinal direction of the separating plate 60. The separation plate 60 is urged toward the fixing belt 21 by a torsion spring (not shown), and the positioning surface 60b comes into contact with the surface of the fixing belt 21, so that the separation plate 60 is finally positioned with respect to the fixing belt 21. .

  Further, since the separation plate 60 is positioned with respect to the fixing belt 21 in one part of the separation plate, a gap at the separation portion between the fixing belt 21 and the separation plate 60 is easily provided.

  The sheet P on which the toner image is placed is fixed by the fixing belt 21 and comes out of the fixing nip N. At this time, it is ideal that the paper P is naturally separated from the fixing belt 21 by the curvature of the fixing belt 21 and the rigidity of the paper P. However, the paper P may be wrapped around the fixing belt 21 due to various factors such as the paper P's strain, humidity, and toner loading.

  As shown in FIG. 1, the separating plate 60 picks up a slight lift of the leading end of the sheet from the surface of the fixing belt 21 by the leading end 60 c and separates the sheet P from the fixing belt 21.

  The separation plate 60 can be provided with the front end portion 60 c in contact with or close to the surface of the fixing belt 21. In FIG. 1, the front end portion 60 c of the separation plate 60 appears to be in contact with the fixing belt 21, but at least in the range of the sheet width, the distance between the fixing belt surface and the front end portion 60 c of the separation plate 60 is less than 1 mm. The gap is provided.

  This is to prevent the surface of the fixing belt 21 from being damaged by the separation plate 60 because the surface of the fixing belt 21 may be scratched when the toner is fixed.

  In the separation plate 60 of the present embodiment, the separation plate longitudinal direction (through the sheet passing surface 60d facing the sheet P to be conveyed and the back surface 60k facing the fixing belt 21 on the side opposite to the sheet passing surface 60d ( An opening 60e is provided over the sheet passing width direction).

  The opening 60e is a hole through which water vapor generated when the paper P is heated escapes upward. When there is no opening 60e, the water vapor that has lost its escape is condensed on the back surface 60k of the separation plate 60 and the like, and flows down to the fixing belt 21 and further adheres to the paper P. Or a toner image abnormality may occur.

  Further, as shown in FIG. 7A and the like, the separation plate 60 of the present embodiment includes a first bent wall portion that is bent so as to rise from the side on the tip end portion 60c side of the opening 60e with respect to the back surface 60k. 60f is provided.

  When the separation plate 60 is configured as described above, the heat capacity of the separation plate 60 can be reduced as compared with the case where the opening 60e is not provided. Further, since the first bending wall portion 60f receives force, the strength of at least the tip end portion 60c side of the separation plate 60 can be maintained over the longitudinal direction of the separation plate. Thereby, the plate | board thickness of the separation plate 60 can be made thinner than the case where the 1st bending wall part 60f is not provided, and the heat capacity of the separation plate 60 can further be reduced.

  Therefore, when the heater 25 is turned on and started to warm from a low temperature environment, the temperature of the separation plate 60 can be increased faster than when the opening 60e and the first bent wall portion 60f are not provided. Water droplets generated on 60 can be eliminated at an early stage.

  FIG. 8 is a six-side view of the separation plate 160 of the comparative example. 8A to 8F show the separation plate 160 viewed from the same direction as that of FIGS. 6A to 6F, respectively.

  Further, reference numeral 160a in FIG. 8 is a rotation shaft hole, reference numeral 160b is a positioning surface, reference numeral 160c is a tip portion, reference numeral 160d is a sheet passing surface, reference numeral 160k is a back surface, and these are FIG. Since it is the same as that of the separation plate 60 shown in FIG.

  9A is a cross-sectional view taken along the line AA in FIG. 8C, and FIG. 9B is an enlarged view of a region B in FIG. 9A.

  The separation plate 160 of the comparative example is provided with a plurality of openings 160e penetrating the paper passing surface 160d and the back surface 160k, divided into a plurality of sections in the longitudinal direction of the separation plate.

  Further, as shown in FIG. 9A and the like, the separation plate 160 is bent so that it rises from the side on the downstream side in the sheet passing direction rather than the front end portion 160c side of the opening portion 160e with respect to the back surface 160k. A wall portion 160f is provided.

  FIG. 10A is an explanatory diagram of a state in which the separation plate 160 receives radiant heat generated from the fixing belt 21 when the separation plate 160 of the comparative example is used. FIG. 10B is an explanatory diagram showing a state in which the separation plate 60 receives radiant heat generated from the fixing belt 21 when the separation plate 60 of the present embodiment is used.

  In the separation plate 160 of the comparative example, as shown in FIG. 10A, the radiant heat generated from the fixing belt 21 indicated by the solid line arrow in the drawing is bent wall portion 160f that is relatively far from the surface of the fixing belt 21. It will be received at. Therefore, when separating the paper P from the fixing belt 21, it is difficult to efficiently receive the radiant heat on the front end 160 c side of the separation plate 160 that easily contacts the paper P.

  Further, since the radiant heat generated from the fixing belt 21 is received at a distance, the radiant heat is removed from the opening 160e as indicated by the dotted arrow in the figure, and the leakage becomes large.

  On the other hand, in the separation plate 60 of the present embodiment, as shown in FIG. 10B, the first bent wall portion that is radiant heat generated from the fixing belt 21 is relatively close to the surface of the fixing belt 21. 60f can be received in the vicinity of the fixing belt 21. Therefore, heat can be efficiently transferred to the separation plate 60 in a high density state.

  Furthermore, heat is transmitted from the first bent wall portion 60f to the vicinity of the front end (separation portion) 60c of the separation plate 60 where the sheet P to be separated is in most contact. Therefore, the temperature in the vicinity of the tip (separation part) of the separation plate 60 can be raised earlier than the separation plate 160 of the comparative example.

  As a matter of course, the bending direction of the first bending wall portion 60f needs to bend toward the direction in which the bending surface is easily subjected to radiant heat from the fixing belt 21, that is, toward the back surface 60k opposite to the paper passing surface 60d. . Further, it is preferable that the bent surface be as parallel as possible to the cylinder centering on the fixing belt 21.

  In FIG. 10, illustrations of components positioned inside the fixing belt 21 and the pressure roller 31 are omitted.

  In addition, minute toner spilled at the time of fixing or the like may adhere to the separation plate 60 and adhere to the paper P and become dirty. Therefore, by applying a fluororesin coating on the paper passing surface 60d of the separation plate 60 and forming a fluororesin layer on the paper passing surface 60d, the toner becomes difficult to adhere to the separation plate 60, and the toner is transferred from the separation plate 60 to the paper P. It is possible to prevent the paper P from adhering and becoming dirty.

  Note that it is more effective to apply the fluororesin coating to the front end (separation part) 60 of the separation plate 60 and the vicinity thereof (cut surface and back surface of the sheet metal).

  Furthermore, a fluororesin coat may be applied to the positioning surface 60b of the separation plate 60. As a result, the frictional force generated between the positioning surface 60b of the separating plate 60 and the surface of the fixing belt 21 is reduced, the amount of wear of the positioning surface 60b of the separating plate 60 and the fixing belt 21 can be reduced, and the life is extended. Can be achieved.

  FIG. 11A is an explanatory diagram when the tip (separation part) 60c of the separation plate 60 is not made thinner than the other parts. FIG. 11B is an explanatory diagram when the tip (separation part) 60c of the separation plate 60 is made thinner than the other parts.

  The tip (separation part) 60c of the separation plate 60 may be made thinner than other portions of the separation plate 60. In this way, the overall plate thickness of the separation plate 60 can be maintained while reducing the gap between the sheet passing surface 60d of the separation plate 60 and the surface of the fixing belt 21, so that the strength against deformation is maintained. However, it is possible to improve the separability by reducing the gap.

  When the tip (separation part) 60c of the separation plate 60 is not made thinner than other portions, the gap between the sheet passing surface 60d of the separation plate 60 and the fixing belt 21 is g1, as shown in FIG.

  On the other hand, when the tip of the separation plate 60 is made thinner than the other portions, the gap between the sheet passing surface 60d of the separation plate 60 and the surface of the fixing belt 21 is g2, as shown in FIG. If it is the thickness of the plate 60, then g1> g2.

  For this reason, g2 having a smaller gap than g1 causes the paper P to collide with the front end surface 60g of the separation plate 60 due to the larger gap, thereby causing the paper P to be damaged or jammed. Can be avoided.

  Various methods for thinning the tip (separation part) 60c of the separation plate 60 are conceivable. For example, if it is performed by press working, it can be performed relatively inexpensively and efficiently.

  FIG. 12A shows a scoop surface 60h that scoops up the leading edge of the conveyed paper P that has entered the opening 60e on the side facing the first bent wall 60f of the opening 60e of the separation plate 60 in the paper passing direction. It is the figure which showed the case where the 2nd bending wall part 60j which has was provided. FIG. 12B is a diagram illustrating a case where the second bent wall portion 60j is not provided on the side facing the first bent wall portion 60f of the opening 60e of the separation plate 60 in the sheet passing direction.

  The opening 60e also functions as a path for releasing water vapor generated by applying heat to the paper P mainly containing moisture, and of course, the larger the area of the opening 60e, the more the air flow (= water vapor). Easy to escape.

  However, if the opening 60e is expanded with respect to the paper direction, the leading edge of the paper P that is transported enters the opening 60e and falls as shown in FIG. In this case, there is a risk of jamming.

  Therefore, as shown in FIG. 12 (a), the second bent wall portion 60j bent so as to rise from the side facing the first bent wall portion 60f of the opening 60e in the sheet passing direction with respect to the back surface 60k is separated. It is provided on the plate 60. Further, a rake face 60h is formed on the second bent wall part 60j at an angle so as to scoop up the paper P that has fallen into the opening 60e with respect to the paper passing face 60d.

  As a result, the leading edge of the paper P that has entered the opening 60e is guided by the rake face 60h and returns onto the paper passing surface 60d, so that damage and jamming of the paper P due to the paper falling into the opening 60e can be suppressed.

  FIG. 13 is a perspective view of a separation plate provided with the opening 60e divided into a plurality of sections in the longitudinal direction of the separation plate. FIG. 14 is a six-side view of the separation plate 60 shown in FIG.

  Specifically, FIG. 14A is a diagram of the separation plate 60 viewed from the direction of the arrow X2 illustrated in FIG. FIG. 14B is a view of the separation plate 60 viewed from the direction of the arrow Z1 shown in FIG. FIG. 14C is a view of the separation plate 60 viewed from the direction of the arrow X1 shown in FIG. FIG. 14D is a view of the separation plate 60 viewed from the direction of the arrow Z2 shown in FIG. FIG. 14E is a view of the separation plate 60 viewed from the direction of the arrow Y2 shown in FIG. FIG. 14F is a diagram of the separation plate 60 viewed from the direction of the arrow Y1 illustrated in FIG.

  15A is a cross-sectional view taken along the line AA in FIG. 14C, and FIG. 15B is an enlarged view of a region B in FIG. 15A.

  The larger the size of the opening 60e provided in the separation plate 60, the more advantageous for removing water vapor. However, when considering the strength of the separation plate 60, the downstream portion and the upstream portion sandwiching the opening 60e in the sheet passing direction of the separation plate 60 are bridged so that the opening 60e is connected to the separation plate longitudinally. It is better to divide into a plurality of sections according to the direction.

  As a result, the strength of the separation plate 60 can be increased as compared with the case where one opening 60e is provided in the longitudinal direction of the separation plate. For example, the removal of jammed paper generated near the fixing nip N is somewhat rough. Even if it is handled, the separating plate 60 can be made difficult to deform.

  FIG. 16 is a perspective view of the separation plate 60 to which the rib 61 is attached. FIG. 17 is a six-side view of the separation plate 60 with the ribs 61 removed from the separation plate 60 shown in FIG.

  Specifically, FIG. 17A is a diagram of the separation plate 60 viewed from the direction of the arrow X2 illustrated in FIG. FIG. 17B is a view of the separation plate 60 viewed from the direction of the arrow Z1 shown in FIG. FIG. 17C is a view of the separation plate 60 viewed from the direction of the arrow X1 shown in FIG. FIG. 17D is a view of the separation plate 60 viewed from the direction of the arrow Z2 shown in FIG. FIG. 17E is a view of the separation plate 60 viewed from the direction of the arrow Y2 shown in FIG. FIG. 17F is a diagram of the separation plate 60 viewed from the direction of the arrow Y1 illustrated in FIG.

  18A is a cross-sectional view taken along the line AA in FIG. 17C, and FIG. 18B is an enlarged view of a region B in FIG.

  As shown in FIG. 17, rib attachment holes 60 i for attaching the ribs 61 are provided in the portion of the sheet passing surface 60 d between the adjacent openings 60 e of the separation plate 60, and are separated from the separation plate 60 there. The rib 61 constituted by is attached as shown in FIG.

  As a result, the paper P separated from the fixing belt 21 at the front end (separation portion) of the separation plate 60 is conveyed while being guided by the rib 61, thereby moving the paper P away from the paper passing surface 60 d of the separation plate 60 by the rib 61. be able to. Therefore, it is possible to suppress image disturbance due to remelting of the toner image fixed on the paper P due to the heat of the separation plate 60 that has been heated to a high temperature due to continuous paper passing or the like.

  Further, it is desirable that the rib 61 is made of a fluororesin. Since the fluororesin is resistant to heat and excellent in slidability, the paper P can be passed through the separator plate 60 that is at a high temperature without being affected by the deformation of the ribs 61.

What has been described above is merely an example, and the present invention has a specific effect for each of the following modes.
(Aspect A)
A fixing belt 21 configured to endlessly move by forming a fixing nip portion such as a fixing nip portion N for fixing an unfixed toner image on the recording medium onto the recording medium while conveying the recording medium such as paper P; Two surface moving bodies such as a pressure roller 31, heating means such as a heater 25 for heating at least one of the two surface moving bodies, and a fixing nip portion positioned on the downstream side in the recording medium conveyance direction. A plate-like member such as a separation plate 60 that is provided for at least one of the surface moving bodies and separates the recording medium that has passed through the fixing nip portion from the surface moving body by bringing the tip portion into contact with or close to the surface of the surface moving body. In the fixing device such as the fixing device 20 provided with the separation member, the separation member has a recording medium facing surface facing the recording medium to be conveyed and a surface movement on the side opposite to the recording medium facing surface. An opening such as an opening 60e passing through the surface facing the surface moving body is provided, and the opening is bent so as to rise from the side on the tip end side of the opening to the surface moving body facing surface. A first bent wall portion such as one bent wall portion 60f is provided.
In (Aspect A), by providing the separation member with an opening that penetrates the recording medium facing surface and the surface moving body facing surface, the heat capacity of the separation member can be reduced as compared with the case where the opening is not provided. It becomes possible. In addition, by having the first bent wall portion on the tip side of the opening provided in the separating member, at least the strength of the leading end portion of the separating member is ensured as compared with the case where the first bent wall portion is not provided. However, the plate thickness of the entire separation member can be reduced. Thereby, since the plate | board thickness of the whole separation member can be made thinner than the case where a 1st bending wall part is not provided, the heat capacity of the whole separation member can be reduced more. Moreover, since the radiant heat from a surface moving body can be received in a 1st bending wall part, the area which receives the said radiant heat can be earned rather than the case where a 1st bending wall part is not provided. Accordingly, it is possible to shorten the temperature raising time of the separation member, and it is possible to evaporate water droplets attached to the separation member at an early stage and to prevent the water droplets from adhering to the recording medium from the separation member.
(Aspect B)
In (Aspect A), the separation member has a positioning portion such as a positioning surface 60b that contacts the surface of the surface moving body and positions the separation member with respect to the surface moving body. According to this, since the position of the separation member is directly determined with respect to the surface moving body as described in the above embodiment, the dimensional accuracy of the separation gap can be increased.
(Aspect C)
In (Aspect A) or (Aspect B), a fluororesin layer is formed on the recording medium facing surface of the separation member. According to this, as described in the above embodiment, it is difficult for the toner to adhere to the recording medium facing surface of the separation member, and the recording medium can be prevented from being contaminated.
(Aspect D)
In (Aspect B) or (Aspect C), a fluororesin layer is formed on at least a surface of the positioning portion that is in contact with the surface of the surface moving body. According to this, as described in the above embodiment, the frictional force between the separation member and the surface moving body is reduced, the amount of wear of the separation member and the surface moving body can be reduced, and the life can be extended. .
(Aspect E)
In (Aspect A), (Aspect B), (Aspect C) or (Aspect D), the tip of the separation member is made thinner than the other part of the separation member. According to this, as described in the above embodiment, the overall plate thickness of the separating member can be maintained while reducing the gap between the recording medium facing surface of the separating member and the surface moving body. Therefore, it is possible to improve the separability by reducing the gap while maintaining the strength against deformation of the separating member.
(Aspect F)
In (Aspect A), (Aspect B), (Aspect C), (Aspect D) or (Aspect E), the separation member is a side facing the side on the tip end side of the opening in the recording medium conveyance direction. To a second bending wall portion such as a rake face 60h bent so as to rise with respect to the surface facing the surface moving body. According to this, as described in the above embodiment, the recording medium can be prevented from being damaged or jammed due to the recording medium falling into the opening.
(Aspect G)
In (Aspect A), (Aspect B), (Aspect C), (Aspect D), (Aspect E) or (Aspect F), the opening is formed in the recording medium width direction perpendicular to the recording medium conveyance direction of the separation member. The part is divided into a plurality of sections. According to this, as described in the above embodiment, the strength of the separating member can be improved.
(Aspect H)
In (Aspect A), (Aspect B), (Aspect C), (Aspect D), (Aspect E), (Aspect F) or (Aspect G), a recording medium is disposed on the surface of the separation member facing the recording medium. A guide member such as a rib 61 capable of guiding conveyance is provided separately from the separation member. According to this, as described in the above embodiment, the recording medium separated from the surface moving body can be guided by the guide member and away from the recording medium facing surface of the separation member. Accordingly, it is possible to suppress image disturbance due to re-melting of the fixed toner image due to the heat of the separating member that has been heated to a high temperature due to continuous paper passing or the like.
(Aspect I)
In (Aspect H), the guide member is made of a fluororesin. According to this, as described in the above embodiment, the recording medium can be transported without being affected by the deformation of the guide member even on the separation member that is resistant to heat and excellent in slidability and becomes hot. .
(Aspect J)
An image carrier such as the photosensitive drum 5; a toner image forming unit such as a developing device 76 that forms a toner image on the image carrier; and the toner image is transferred from the image carrier onto a recording medium such as paper P. In the image forming apparatus such as a printer provided with a transfer unit such as the intermediate transfer unit 85 and a fixing unit such as the fixing device 20 for fixing the toner image transferred onto the recording medium to the recording medium, The fixing device of (Aspect A), (Aspect B), (Aspect C), (Aspect D), (Aspect E), (Aspect F), (Aspect G), (Aspect H) or (Aspect I) is used. According to this, as described in the above embodiment, it is possible to suppress the adhesion of water droplets from the separation member to the recording medium while ensuring the strength of the separation member such as the separation plate 60, and to perform good image formation. Can do.

DESCRIPTION OF SYMBOLS 1 Printer main body 3 Exposure part 4 Image forming part 5 Photosensitive drum 12 Paper feed part 20 Fixing device 21 Fixing belt 21a Inner peripheral surface 22 Heat transfer member 23 Reinforcement member 25 Heater 26 Nip forming member 28 Sliding sheet 31 Pressure roller 32 Metal core 33 Elastic layer 40 Temperature sensor 42 Bearing 43 Side plate 45 Gear 50 Contact / separation mechanism 51 Pressure lever 51a Support shaft 52 Eccentric cam 53 Pressure spring 60 Separating plate 60a Rotating shaft hole 60b Positioning surface 60c Tip 60d Paper passing surface 60e Opening 60f First bent wall portion 60g End side end surface 60h Rake surface 60i Rib mounting hole 60j Second bent wall portion 60k Rear surface 61 Rib 75 Charging device 76 Developing device 77 Cleaning device 78 Intermediate transfer belt 79 Primary transfer bias roller 80 Intermediate transfer cleaning device 82 Secondary transfer back Up roller 83 Cleaning backup roller 84 Tension roller 85 Intermediate transfer unit 89 Secondary transfer roller 97 Paper feed roller 98 Registration roller pair 99 Paper discharge roller pair 100 Stack part 101 Bottle storage part 102 Toner bottle 160 Separator plate 160a Rotating shaft hole 160b Positioning surface 160c Front end 160d Paper passing surface 160e Opening portion 160f Bending wall portion 160k Back surface

JP 2011-237642 A

Claims (10)

Two surface moving bodies configured to endlessly move by forming a fixing nip portion for fixing an unfixed toner image on the recording medium onto the recording medium while conveying the recording medium;
Heating means for heating at least one of the two surface moving bodies;
Located on the downstream side in the recording medium conveyance direction with respect to the fixing nip portion, provided on at least one of the two surface moving bodies, and by bringing the tip portion into contact with or close to the surface of the surface moving body, In a fixing device comprising a plate-shaped separation member that separates the recording medium that has passed through the fixing nip from the surface moving body,
The separation member is provided with an opening penetrating a recording medium facing surface facing the recording medium to be conveyed and a surface moving body facing surface facing the surface moving body on the side opposite to the recording medium facing surface. And
A fixing device comprising: a first bent wall portion bent so as to rise from a side of the opening portion on the tip end side with respect to the surface facing the surface moving body. The fixing device according to claim 1.
The fixing device according to claim 1, wherein the separation member includes a positioning unit that contacts a surface of the surface moving body and positions the separation member with respect to the surface moving body. The fixing device according to claim 1 or 2,
A fixing device, wherein a fluororesin layer is formed on the surface of the separating member facing the recording medium. The fixing device according to claim 2 or 3,
A fixing device, wherein a fluororesin layer is formed on at least a surface of the positioning portion in contact with the surface of the surface moving body. The fixing device according to claim 1, 2, 3 or 4.
The fixing device according to claim 1, wherein the tip end portion of the separating member is thinner than other portions of the separating member. The fixing device according to claim 1, 2, 3, 4 or 5.
The separating member has a second bent wall portion that is bent so as to rise from the side facing the tip side of the opening in the recording medium conveyance direction with respect to the surface facing the surface moving body. Fixing device to do. The fixing device according to claim 1, 2, 3, 4, 5 or 6.
The fixing device, wherein the opening is divided into a plurality of sections in a recording medium width direction perpendicular to the recording medium conveyance direction of the separating member. The fixing device according to claim 1, 2, 3, 4, 5, 6 or 7.
A fixing device, wherein a guide member capable of guiding conveyance of a recording medium is provided separately from the separation member on the recording medium facing surface of the separation member. The fixing device according to claim 8.
The fixing device, wherein the guide member is made of a fluororesin. An image carrier;
Toner image forming means for forming a toner image on the image carrier;
Transfer means for transferring the toner image from the image carrier onto a recording medium;
An image forming apparatus comprising: a fixing unit that fixes the toner image transferred onto the recording medium to the recording medium;
An image forming apparatus using the fixing device according to claim 1, 2, 3, 4, 5, 6, 7, 8, or 9 as the fixing unit.

Images