JP2016061925A - Fixation device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixation device which suppresses the generation of image disturbance, and an image forming apparatus comprising the fixation device.SOLUTION: A fixation device comprises: a first pressing part (704) that includes a pressing member 70 disposed inside a pressure belt 520, the pressing member 70 pressing the pressure belt 520 against a heating roll 510 to form a nip part N for allowing a recording medium to pass through between the heating roll 510 and the pressure belt 520; second pressing parts (701 and 702) that press the pressure belt 520 against the heating roll 510 upstream of the nip part N in a conveyance direction A; a recess (703) that is provided with a space between the recess and the pressure belt 520 upstream of the first pressing part in the conveyance direction A but downstream of the second pressing part in the conveyance direction A: a through hole 740 that, when a lubricant supplied to an inner surface of the pressure belt 520 flows into the recess, discharges the lubricant from the recess to the outside of the pressing member 70 through the inside of the pressing member 70.SELECTED DRAWING: Figure 3

Description

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

  In an image forming apparatus such as a copying machine or a printer using an electrophotographic system, an unfixed toner image formed on a recording medium such as recording paper is fixed by a fixing device to form an image. As a fixing device used in such an image forming apparatus, for example, a first rotating body such as a heating roll, a second rotating body such as a pressure belt rotating in contact with the first rotating body, and the second A pressing member that is disposed on the inner peripheral surface of the rotating body, presses the second rotating body against the first rotating body, and forms a nip portion through which the recording medium passes between the first rotating body and the second rotating body; There is known a fixing device comprising:

  In the case of the fixing device configured to press the second rotating body against the surface of the first rotating body by the pressing member as described above, when the sliding resistance (friction coefficient) between the second rotating body and the pressing member increases. In some cases, the rotation of the second rotating body becomes difficult to correspond to the first rotating body, and paper wrinkles, image disturbance, and the like may occur. For this reason, there is a technique for suppressing an increase in sliding resistance between the second rotating body and the pressing member by supplying a lubricant between the second rotating body and the pressing member or arranging a sliding sheet. (For example, refer patent documents 1-4).

  By the way, as a pressing member used in the fixing device, for example, it is provided inside the inner peripheral surface of the endless belt (second rotating body), and at the facing portion between the endless belt and the heating rotating body (first rotating body). A first pressing portion that forms a nip portion for passing a recording medium holding an image between the endless belt and the heating rotator by pressing the outer peripheral surface of the endless belt against the heating rotator; and the nip portion By pushing the endless belt toward the heating rotator at the upstream side of the recording medium in the transport direction, the recording medium contacts the heating rotator at the upstream side of the nip portion in the transport direction of the recording medium. A second pressing unit that guides the recording medium, and an upstream side of the first pressing unit in the transport direction of the recording medium and a downstream side of the second pressing unit in the transport direction of the recording medium. Te, the pressing member having a recess provided at a said endless belt and space have been proposed (e.g., see Patent Document 5).

  In recent years, in order to reduce the number of parts of the fixing device and reduce the cost, a fixing device in which no sliding sheet is provided between the second rotating body and the pressing member has been studied.

JP 2003-195664 A JP 2004-109668 A JP 2006-91182 A JP 2006-91499 A JP 2013-250437 A

  An object of the present invention is a nip that contacts an inner surface of a second rotating body, presses the second rotating body against the first rotating body, and allows a recording medium to pass between the first rotating body and the second rotating body. A first pressing portion that forms a portion and a second pressing member that is in contact with the inner surface of the second rotator and pushes the second rotator toward the first rotator upstream of the nip portion in the conveyance direction of the recording medium. A pressing portion; and a recess provided on the upstream side of the first pressing portion in the recording medium conveyance direction and on the downstream side of the second pressing portion in the recording medium conveyance direction with a space of the second rotating body therebetween. A fixing member using a pressing member having a pressing member that accumulates in the recess without being discharged out of the recess when the lubricant supplied to the inner surface of the second rotating body flows into the recess. Fixing that suppresses the occurrence of image distortion compared to devices Location, and to provide an image forming apparatus having the fixing device.

  The invention according to claim 1 includes a first rotating body, a second rotating body disposed in contact with an outer surface of the first rotating body, and a pressing member disposed inside the second rotating body. The pressing member is in contact with the inner surface of the second rotating body, presses the second rotating body against the first rotating body, and a recording medium is interposed between the first rotating body and the second rotating body. A first pressing portion that forms a nip portion to be passed through and an inner surface of the second rotator, and the second rotator is directed toward the first rotator on the upstream side of the nip portion in the conveyance direction of the recording medium. A second pressing portion that is pressed and the upstream side of the first pressing portion in the transport direction of the recording medium and the downstream side of the second pressing portion in the transport direction of the recording medium, with a space from the second rotating body. And the lubricant supplied to the inner surface of the second rotating body flows into the recess. When the a fixing device having a through hole for discharging to the outside of the pressing member through the inside of the pressing member said lubricant from said recess.

  The invention according to claim 2 is the fixing device according to claim 1, comprising a foam filled in the through hole.

  According to a third aspect of the present invention, there is provided an image carrier, latent image forming means for forming a latent image on the surface of the image carrier, and developing the latent image using a developer for developing an electrostatic image to form a toner image. The fixing unit according to claim 1, further comprising: a developing unit that forms; a transfer unit that transfers the toner image to a recording medium; and a fixing unit that fixes the toner image to the recording medium. An image forming apparatus is an apparatus.

  According to the first aspect of the present invention, the recording medium is in contact with the inner surface of the second rotating body, presses the second rotating body against the first rotating body, and between the first rotating body and the second rotating body. A first pressing portion that forms a nip portion through which the toner passes, and an inner surface of the second rotating body, and the second rotating body is directed toward the first rotating body on the upstream side of the nip portion in the conveyance direction of the recording medium. A second pressing portion that is pressed and is provided upstream of the first pressing portion in the recording medium conveyance direction and downstream of the second pressing portion in the recording medium conveyance direction with a space of the second rotating body therebetween. A pressing member having a concave portion, and when the lubricant supplied to the inner surface of the second rotating body flows into the concave portion, the pressing member that accumulates in the concave portion without being discharged out of the concave portion. Compared to the fixing device used, image distortion is suppressed. That the fixing device is provided.

  According to the second aspect of the present invention, the recording medium is in contact with the inner surface of the second rotating body, presses the second rotating body against the first rotating body, and between the first rotating body and the second rotating body. A first pressing portion that forms a nip portion through which the toner passes, and an inner surface of the second rotating body, and the second rotating body is directed toward the first rotating body on the upstream side of the nip portion in the conveyance direction of the recording medium. A second pressing portion that is pressed and is provided upstream of the first pressing portion in the recording medium conveyance direction and downstream of the second pressing portion in the recording medium conveyance direction with a space of the second rotating body therebetween. A pressing member having a concave portion, and when the lubricant supplied to the inner surface of the second rotating body flows into the concave portion, the pressing member that accumulates in the concave portion without being discharged out of the concave portion. Compared to the fixing device used, the occurrence of image distortion is further suppressed. A fixing device is provided to be.

  According to the invention of claim 3, the recording medium is in contact with the inner surface of the second rotating body, presses the second rotating body against the first rotating body, and between the first rotating body and the second rotating body. A first pressing portion that forms a nip portion through which the toner passes, and an inner surface of the second rotating body, and the second rotating body is directed toward the first rotating body on the upstream side of the nip portion in the conveyance direction of the recording medium. A second pressing portion that is pressed and is provided upstream of the first pressing portion in the recording medium conveyance direction and downstream of the second pressing portion in the recording medium conveyance direction with a space of the second rotating body therebetween. A pressing member having a concave portion, and when the lubricant supplied to the inner surface of the second rotating body flows into the concave portion, the pressing member that accumulates in the concave portion without being discharged out of the concave portion. Compared to the image forming apparatus equipped with the fixing device used, Image forming apparatus is provided which generates disturbance is suppressed.

1 is a schematic configuration diagram illustrating an example of a configuration of an image forming apparatus according to an exemplary embodiment. 2 is a schematic perspective view illustrating an example of a configuration of a fixing device according to the exemplary embodiment. FIG. FIG. 3 is a schematic cross-sectional view of the fixing device shown in FIG. 2. FIG. 3 is an exploded perspective view of the fixing device shown in FIG. 2. It is a disassembled perspective view of a pressurization module. It is a disassembled perspective view of the pressurization member installed in a pressurization module. It is a model perspective view of the pressing member provided in the pressurization member. It is a model side view of the pressing member seen from the IX direction in FIG. (A) is a schematic side view of the pressing member seen from the Xa direction in FIG. 7, (b) is a schematic side view of the pressing member seen from the Xb direction in FIG. FIG. 2 is an enlarged schematic side view of a fixing device according to an exemplary embodiment. It is a model top view when an opposing surface is seen from the upper part side in FIG.

  Embodiments of the present invention will be described below. This embodiment is an example for carrying out the present invention, and the present invention is not limited to this embodiment.

<Image forming apparatus>
FIG. 1 is a schematic configuration diagram illustrating an example of a configuration of an image forming apparatus according to the present embodiment.

  An image forming apparatus 1 shown in FIG. 1 includes an image forming unit 10 that forms an image, an intermediate transfer belt 20 to which an image formed by the image forming unit 10 is primarily transferred, and an image that is primarily transferred to the intermediate transfer belt 20. Is transferred to a recording medium (hereinafter referred to as paper P), a secondary transfer device 30, a paper supply unit 40 that supplies the paper P toward the secondary transfer device 30, and a paper P by the secondary transfer device 30. The image forming apparatus 1 includes a fixing device 50 that fixes the second-transferred image, and a control unit 60 that controls the operation of each unit constituting the image forming apparatus 1. In addition, the image forming apparatus 1 includes a main body casing 1a that accommodates these components therein, and a sheet on which an image is fixed by passing through the fixing device 50 is disposed above the main body casing 1a. A paper discharge stacking portion 1b for stacking P is provided.

  The image forming unit 10 includes a plurality of image forming units 10Y, 10M, 10C, and 10K that form toner images of respective color components by an electrophotographic method. Each of these image forming units 10Y, 10M, 10C, and 10K includes They are arranged side by side so as to face the intermediate transfer belt 20. Here, the plurality of image forming units 10Y, 10M, 10C, and 10K form yellow, magenta, cyan, and black images, respectively.

  Each of the plurality of image forming units 10Y, 10M, 10C, and 10K includes a photosensitive drum 11 (image holding member) that rotates in a direction indicated by an arrow in the drawing. Further, in each of the image forming units 10Y, 10M, 10C, and 10K, around the photosensitive drum 11, a charging device 12 (charging unit) that charges the photosensitive drum 11, and the photosensitive drum 11 is exposed to electrostatic. An exposure device 13 (latent image forming means) for forming a latent image, development for developing a toner image by developing the electrostatic latent image on the photosensitive drum 11 with a corresponding color toner (developer for developing an electrostatic image). An apparatus 14 (developing means) is provided. Further, in each of the image forming units 10Y, 10M, 10C, and 10K, a primary transfer device 15 that transfers each color component toner image formed on the photosensitive drum 11 to the intermediate transfer belt 20, and a residual on the photosensitive drum 11 A drum cleaning device 16 for removing toner is provided.

  Next, the intermediate transfer belt 20 is wound around two roll members 21 and 22 that are rotatably provided, and is provided to rotate in a direction indicated by an arrow in the drawing. In this embodiment, the roll member 21 is used to drive the intermediate transfer belt 20. In the present embodiment, the roll member 22 is disposed opposite to the secondary transfer roll 31 with the intermediate transfer belt 20 interposed therebetween, and the secondary transfer device 30 is configured by the secondary transfer roll 31 and the roll member 22. ing. A belt cleaning device (not shown) for removing residual toner on the intermediate transfer belt 20 is provided at a position facing the roll member 21 with the intermediate transfer belt 20 interposed therebetween.

  The paper supply unit 40 is disposed below the image forming unit 10, and includes a paper storage unit 41 that stores the paper P used in the image forming apparatus 1, and a supply roll that supplies the paper P stored in the paper storage unit 41. 42, a transport path 43 through which the paper P supplied by the supply roll 42 is transported, and a transport roll 44 that transports the paper P in the transport path 43. Here, the conveyance path 43 is provided so as to reach from the sheet storage unit 41 to the paper discharge stacking unit 1b through the secondary transfer device 30 and the fixing device 50 in the main body housing unit 1a.

  The fixing device 50 includes a heating module 51 and a pressure module 52 as will be described later. The heating module 51 is disposed so as to face the surface (one surface) of the paper P that faces the intermediate transfer belt 20 (roll member 22) when passing through the secondary transfer device 30. Further, the pressure module 52 is disposed so as to face the surface (the other surface) of the paper P that faces the secondary transfer roll 31 when passing through the secondary transfer device 30. In the following description, the direction of arrow A shown in FIG.

  Next, the operation of the image forming apparatus shown in FIG. 1 will be described.

  Along with receiving image information from an external device (not shown), the control unit 60 creates exposure data based on the image information and outputs it to each exposure device 13 in the image forming unit 10, and configures the image forming device 1. An operation start control signal is output to each unit.

  In the yellow (Y) image forming unit 10Y, for example, the photosensitive drum 11 that is rotationally driven in the direction of the arrow in the drawing is charged by the charging device 12 and emits light based on the exposure data supplied from the control unit 60. Exposure is performed by the exposure device 13. As a result, an electrostatic latent image related to the yellow image is formed on the photosensitive drum 11. The electrostatic latent image formed on the photosensitive drum 11 is developed by the developing device 14, and a yellow toner image is formed on the photosensitive drum 11. Similarly, in the other image forming units 10M, 10C, and 10K, magenta (M), cyan (C), and black (K) toner images are formed according to the above-described procedure.

  The toner images formed on the photoconductive drums 11 of the image forming units 10Y, 10M, 10C, and 10K are primarily transferred to the intermediate transfer belt 20 that is rotationally driven in the direction of the arrow in the drawing by the primary transfer device 15 provided in each. Transfer (electrostatic transfer) is performed, and the image is superimposed on the intermediate transfer belt 20. Then, the toner image superimposed on the intermediate transfer belt 20 moves to the secondary transfer position where the secondary transfer device 30 is provided as the intermediate transfer belt 20 rotates. The residual toner remaining on each photosensitive drum 11 after the primary transfer is removed by a drum cleaning device 16 provided in each image forming unit 10Y, 10M, 10C, 10K.

  On the other hand, in the paper supply unit 40, the paper P stored in the paper storage unit 41 is taken out one by one using the supply roll 42 and sent out to the transport path 43. After that, the transport roll 44 provided in the transport path 43 causes the paper P sent from the paper storage unit 41 to be fed in accordance with the timing at which the superimposed toner image on the intermediate transfer belt 20 reaches the secondary transfer position. Transport toward the next transfer position.

  Then, the toner image on the intermediate transfer belt 20 is secondarily transferred (electrostatic transfer) to the paper P passing the secondary transfer position by the secondary transfer device 30. At this time, the secondary transfer of the toner image is performed on the surface of the paper P facing the intermediate transfer belt 20.

  When the paper P on which the toner image is transferred passes through the fixing device 50, the transfer surface of the toner image on the paper P is heated by the heating module 51, and the paper P is heated by the heating module 51 and the pressure module 52. By being pressurized, the toner image is fixed on the paper P. Thereafter, the paper P on which the toner image is fixed by passing through the fixing device 50 is discharged to the paper discharge stacking unit 1b. Further, residual toner remaining on the intermediate transfer belt 20 after passing through the secondary transfer position is removed by a belt cleaning device (not shown).

  Next, the configuration of the fixing device 50 of this embodiment will be described.

  FIG. 2 is a schematic perspective view showing an example of the configuration of the fixing device according to the embodiment of the present invention. FIG. 3 is a schematic cross-sectional view of the fixing device shown in FIG. 2. Here, a cross-section taken along line IV-IV in FIG. 2 is shown. FIG. 4 is an exploded perspective view of the fixing device shown in FIG. FIG. 5 is an exploded perspective view of the pressure module. FIG. 6 is an exploded perspective view of a pressure member (details will be described later) installed in the pressure module.

  The fixing device 50 of this embodiment includes a heating module 51, a pressure module 52, and a support module 53. In the present embodiment, the heating roll 510 (first rotating body) provided in the heating module 51 and the pressure belt 520 (second rotating body) provided in the pressure module 52 are in contact with each other at the opposite portions. Thus, a nip portion N through which the paper P passes is formed. And the support module 53 which supports the heating module 51 and the pressurization module 52 is attached to the fixing housing | casing part not shown.

  The heating roll 510 of the present embodiment has, for example, a roll shape, and contacts the paper P that passes through the nip portion N to heat the paper P. The heating roll 510 according to the present embodiment includes a cylindrical member 511 formed in a cylindrical shape, a heating element 512 that is disposed inside the inner peripheral surface of the cylindrical member 511, and generates heat when power is supplied, and an outer peripheral surface of the cylindrical member 511. A covering member 513 that covers a portion excluding both ends in the axial direction, and a gear 514 that is fixedly attached to a portion that is not covered by the covering member 513 at the inner end of the outer peripheral surface of the cylindrical member 511. ing. Note that, in the heating roll 510, exposed portions 515 where the outer peripheral surface of the cylindrical member 511 is exposed by being not covered by the covering member 513 are provided on both ends in the axial direction of the cylindrical member 511.

  The cylindrical member 511 is made of, for example, a metal pipe such as aluminum or stainless steel. Further, the heating element 512 is composed of, for example, a halogen lamp. Further, the covering member 513 is made of a material such as rubber having heat resistance and elasticity, for example. However, as the covering member 513, a member in which an elastic layer (rubber or the like) laminated on the outer peripheral surface of the cylindrical member 511 and a release layer (fluorine resin or the like) laminated on the elastic layer is used. Also good. The gear 514 meshes with a gear (not shown) provided on the rear side of the main body casing 1a of the image forming apparatus when the fixing device 50 is attached to the image forming apparatus. The heating roll 510 is rotated by receiving a driving force from the part 1a side.

  The pressurizing module 52 of the present embodiment has, for example, an endless belt-like shape. The pressurizing belt 520 presses the paper P passing through the nip portion N between the heating rolls 510 and the pressurizing belt 520. The pressure member 521 is disposed inside the inner peripheral surface of the pressure belt and pressurizes the pressure belt 520 against the heating roll 510. The pressure member 521 is disposed inside the inner peripheral surface of the pressure belt 520. A belt holding member 522 that supports the belt in a fixed state and holds the pressure belt 520 in a rotatable state, and a pressure that is attached to the belt holding member 522 outside the both ends in the axial direction of the pressure belt 520 and rotates. And a regulating member 523 that regulates meandering of the belt 520. Here, the regulating member 523 is attached to each end of the belt holding member 522 in the axial direction. Further, the pressure module 52 is fixedly attached to the belt holding member 522 at a position facing the inner peripheral surface of the pressure belt 520, and comes into contact with the inner peripheral surface of the pressure belt 520 so that the pressure belt 520 A lubricant supply member 524 for supplying a lubricant to the inner peripheral surface is further provided.

  The pressure belt 520 of the present embodiment is configured, for example, by forming a release layer such as a fluororesin on the surface of a belt base material formed in a thin cylindrical shape with a synthetic resin such as polyimide. It is desirable.

  The pressure member 521 of the present embodiment is disposed in a portion of the inside of the pressure belt 520 that faces the heating roll 510 with the pressure belt 520 interposed therebetween, and the pressure belt 520 via the inner peripheral surface of the pressure belt 520. The pressing member 70 that forms the nip portion N by pressing the 520 against the heating roll 510 side is attached to the back side of the pressing member 70 as viewed from the nip portion N, and supports the pressing member 70 inside the pressure belt 520. And a pressing support member 80 attached to the belt holding member 522 via the regulating member 523.

  The pressing member 70 of the present embodiment has a facing surface (details will be described later) formed on the side facing the pressure belt 520, and a groove portion 71 for inserting the pressing support member 80 is axially provided behind the pressing surface. It is provided along. Further, the pressing member 70 includes two projecting portions 73 that project from the both axial end portions of the pressing member 70 along the axial direction and toward the outside. The pressing member 70 of the present embodiment is formed by integrally molding a synthetic resin having heat resistance, for example. Moreover, the hardness of the pressing member 70 is preferably lower than that of the cylindrical member 511 in the heating roll 510 and higher than that of the covering member 513 in the heating roll 510, for example.

  The pressing support member 80 of the present embodiment is formed in a plate shape, and one end of the pressing support member 80 is inserted into the groove portion 71 of the pressing member 70. The pressing support member 80 is configured integrally with the pressing portion 81 and is viewed from the pressing portion 81. And a bent portion 82 set to be bent at 90 °. Here, both end portions in the axial direction of the pressing portion 81 are positioned outside the both end portions in the axial direction of the bent portion 82, and these two protruding portions in the pressing portion 81 become the protruding portions 83, respectively. Yes. The pressing support member 80 is formed by performing various processes on a metal plate such as stainless steel.

  The belt holding member 522 of the present embodiment extends along an axial direction intersecting the rotation direction of the pressure belt 520 and opens toward the heating roll 510 so that the holding body 5221 has a U-shaped cross section. And a plurality of ribs 5222 provided in the axial direction on the outer peripheral surface of the holding main body 5221 and each formed along the belt rotation direction, and side walls 5223 provided at both axial ends of the holding main body 5221. ing. Of the plurality of ribs 5222 provided on the belt holding member 522, each of the plurality of ribs 5222 disposed in the central portion in the axial direction of the holding body 5221 has a notch for mounting the lubricant supply member 524. Is provided.

  Here, each of the two side walls 5223 of the belt holding member 522 is provided with a first convex portion 5223a and a second convex portion 5223b that protrude along the axial direction and outward. Each of the two side walls 5223 is provided with a notch 5223c formed so as to face the same side as the opening provided on the outer peripheral surface of the holding body 5221. Note that the belt holding member 522 of the present embodiment is configured by integrally molding a synthetic resin having heat resistance, for example.

  Each of the two regulating members 523 includes a regulating body 5231 having a circular shape and one end cut out linearly, and each regulating body 5231 has a side facing the pressure member 521. 1st recessed part 5231a and 2nd recessed part 5231b provided in this, and the rectangular through-hole 5231c provided by penetrating each control main body 5231 are provided.

  The lubricant supply member 524 of the present embodiment has a rectangular parallelepiped shape, and the axial direction of the outer peripheral surface of the holding body 5221 in the belt holding member 522 is not provided with a plurality of ribs 5222. Attached along. The lubricant supply member 524 is made of, for example, sponge or felt, and the inside thereof is impregnated with a lubricant such as lubricating oil.

  The support module 53 of the present embodiment is attached to a roll support member 531 that supports the heating module 51 including the heating roll 510 and a roll support member 531 so as to be rotatable, and a pressurizing belt 520 is provided. A belt support member 532 that supports the module 52, two slide bearings 533 that are attached to the roll support member 531 and that rotatably support the heating roll 510 in the heating module 51 at both axial ends thereof, a heating roll 510, and Attached across the roll support member 531 and the belt support member 532 at both axial ends of the pressure belt 520, the heating roll 510 and the pressure in the heating module 51 are pressed through the roll support member 531 and the belt support member 532. Addition in module 52 And a two tension springs 534 for imparting a force to form a nip portion N between the belt 520.

  The roll support member 531 of this embodiment is provided along the axial direction of the two heating side plates 5311 and the two side plates 5311 provided on both ends in the axial direction of the heating roll 510, and connects these two side plates 5311. Two connecting plates 5312 are provided. Each of the two side plates 5311 has a shaft portion 5311a for attaching the belt support member 532, a spring attachment portion 5311b for attaching one end of the tension spring 534, and a bearing attachment portion for attaching the slide bearing 533. 5311c. In this embodiment, a part of the connecting plate 5312 is a guide (guide member) that guides the conveyed paper P toward the nip portion N side on the upstream side of the nip portion N in the transport direction A. ).

  The belt support member 532 of this embodiment includes two side plates 5321 provided corresponding to the two side plates 5311 of the roll support member 531. Each of these two side plates 5321 has a shaft mounting hole 5321a into which a shaft portion 5311a provided in the roll support member 531 is rotatably inserted, and a spring mounting hole for mounting the other end of the tension spring 534. 5321b and a fitting portion 5321c into which the protruding portion 83 provided on the pressing support member 80 of the pressure member 521 of the pressure module 52 is fitted are provided.

  The two plain bearings 533 are fitted into the two bearing mounting portions 5311 c of the roll support member 531, respectively, and are in contact with the two exposed portions 515 of the heating roll 510.

  One end of the tension spring 534 of this embodiment is attached to a spring mounting portion 5311b provided on the roll support member 531, and the other end is attached to a spring mounting hole 5321b provided on the belt support member 532. Yes.

  Next, an example of the assembly structure of the fixing device 50 of this embodiment will be described.

  The heating roll 510 constituting the heating module 51 of the present embodiment is fixed by inserting a heating element 512 into a cylindrical member 511 provided with a covering member 513 and an exposed portion 515 on the outer peripheral surface thereof. At the same time, a gear 514 is fixed to the outer peripheral surface of one end portion in the axial direction.

  In the pressurizing module 52 of the present embodiment, the pressurizing member 521 is configured by inserting one end side of the pressing portion 81 of the pressing support member 80 into the groove portion 71 provided in the pressing member 70. The pressure member 521 is inserted into the belt holding member 522 from an opening provided in the holding body 5221 of the belt holding member 522. Thereby, the facing surface of the pressing member 70 of the pressing member 521 is positioned in the opening of the holding body 5221. At this time, the protruding portions 83 provided on the pressing portion 81 of the pressing member 521 protrude from the side walls 5223 of the belt holding member 522, respectively. A lubricant supply member 524 is attached to the outer peripheral surface of the holding body 5221 along the axial direction.

  Further, in the pressurizing module 52 of the present embodiment, a belt holding member 522 that houses the pressurizing member 521 inside and has a lubricant supply member 524 mounted on the outside is inserted inside the pressurizing belt 520. At this time, the plurality of ribs 5222 provided on the outer peripheral surface of the belt holding member 522 and the lubricant supply member 524 attached to the outer peripheral surface of the belt holding member 522 respectively face the inner peripheral surface of the pressure belt 520. It is in a state.

  Furthermore, in the pressurizing module 52 of the present embodiment, the pressurizing member 521 is housed inside, the lubricant supply member 524 is mounted on the outside, and the shaft of the belt holding member 522 inserted into the pressurizing belt 520 is further provided. Restricting members 523 are attached to both ends in the direction. And the 1st convex part 5223a and the 2nd convex part 5223b which were provided in the axial direction both ends of the belt holding member 522 are each inserted in the 1st recessed part 5231a and the 2nd recessed part 5231b in each regulating member 523. . At both ends in the axial direction of the belt holding member 522, the edge side of the regulating member 523 protrudes beyond the outer peripheral surface of the belt holding member 522, and this portion is opposed to both ends in the axial direction of the pressure belt 520. By doing so, the meandering of the pressure belt 520 during rotation is regulated. In addition, in the through holes 5231 c provided in each regulation main body 5231, protrusions 83 provided at both ends in the axial direction of the pressing support member 80 of the pressing member 521 are provided on the side wall 5223 of the belt holding member 522. Through the notch 5223c, it is inserted and fitted.

  Thus, in the present embodiment, the pressure belt 520, the pressure member 521, and the belt holding member 522 to which the lubricant supply member 524 is attached are integrated via the two regulating members 523, and the pressure module 52 is constituted. And the protrusion part 83 provided in the pressing support member 80 of the pressurization member 521 protrudes toward the outer side from the axial direction both ends of the pressurization module 52, respectively.

  On the other hand, in the support module 53 of this embodiment, the shaft portions 5311 a provided on the two side plates 5311 of the roll support member 531 are mounted on the shafts provided on the two side plates 5321 constituting the belt support member 532, respectively. It fits into the hole 5321a. And the protrusion part 83 which protrudes from the axial direction both ends side of the pressurization module 52 is engage | inserted by the fitting part 5321c provided in each of the two side plates 5321 which comprise the belt support member 532. As a result, the pressure module 52 is supported by the two side plates 5321 constituting the belt support member 532 and is held in a rotatable state with respect to the roll support member 531 via these two side plates 5321. .

  Further, in the support module 53 of the present embodiment, the slide bearings 533 are respectively attached to the bearing mounting portions 5311 c provided on the two side plates 5311 of the roll support member 531. Of the two slide bearings 533, the slide bearing 533 provided on the front side is the formation part of the exposed portion 515 provided on the front side of the heating roll 510, and the slide bearing 533 provided on the rear side is The heating roller 510 is configured to support the formation portion of the exposed portion 515 provided on the rear side. The heating roll 510 is rotatably supported by the roll support member 531 via two sliding bearings 533.

  Furthermore, in the support module 53 of the present embodiment, one end of the tension spring 534 provided on the front side is attached to the spring mounting portion 5311b of the side plate 5311 provided on the front side of the roll support member 531, and the others. The end is attached to a spring mounting hole 5321 b of a side plate 5321 provided on the front side of the belt support member 532. On the other hand, in the support module 53, one end of the tension spring 534 provided on the rear side is attached to the spring mounting portion 5311b of the side plate 5311 provided on the rear side of the roll support member 531, and the other end is attached to the belt. The support member 532 is attached to a spring mounting hole 5321b of a side plate 5321 provided on the rear side.

  As a result, the heating module 51 supported by the roll support member 531 and the pressurizing module 52 supported by the belt support member 532 include two shaft portions 5311 a provided on the roll support member 531, and the belt support member 532. A heating roll 510 provided in the heating module 51 and a pressure belt 520 provided in the pressure module 52 by two tension springs 534 centering on a connecting portion with the two shaft mounting holes 5321a provided in the Is pushed in the direction of contact. At this time, the pressing member 70 provided in the pressurizing module 52 presses the heating roll 510 provided in the heating module 51 via the pressurizing belt 520 provided in the pressurizing module 52, and presses the heating roll 510. Between the pressure belt 520, a nip portion N is formed.

  Next, an example of the configuration of the pressing member 70 provided on the pressing member 521 will be described in detail.

  FIG. 7 is a schematic perspective view of the pressing member provided in the pressing member, and FIG. 8 is a schematic side view of the pressing member as viewed from the IX direction in FIG. FIG. 9A is a schematic side view of the pressing member as viewed from the Xa direction in FIG. 7, and FIG. 9B is a schematic side view of the pressing member as viewed from the Xb direction in FIG. In FIG. 7, a through hole 740 penetrating the inside of the pressing member 70 described later is omitted, and in FIG. 8, the through hole 740 penetrating the pressing member 70 is indicated by a broken line.

  In the pressing member 70 of the present embodiment, when the pressing module 52 is configured, a facing surface 700 placed at a position facing the inner peripheral surface of the pressing belt 520 and a through hole 740 penetrating the pressing member 70 are provided. Is provided.

  The opposing surface 700 provided on the pressing member 70 is a first opposing surface 701, a second opposing surface 702 following the first opposing surface 701, and a third opposing surface following the second opposing surface 702 in order from the upstream side in the transport direction A. 703 and a fourth facing surface 704 following the third facing surface 703. In the present embodiment, the fourth facing surface 704 is in contact with the inner surface of the pressure belt 520 and is pressed against the heating roll 510 to form a nip portion N between the heating roll 510 and the pressure belt 520. Part. In the present embodiment, the first facing surface 701 and the second facing surface 702 are in contact with the inner surface of the pressure belt 520, and the pressure belt 520 is connected to the heating roll 510 on the upstream side in the transport direction A from the nip portion N. It becomes the 2nd pressing part pushed toward. Further, in the present embodiment, the third facing surface 703 separates the pressure belt 520 from the space on the upstream side in the transport direction A from the first pressing unit and on the downstream side in the transport direction A from the second pressing unit. It becomes a recessed part provided.

  Of the facing surface 700 provided on the pressing member 70, the first facing surface 701 is configured by a plane formed from the upstream side in the transport direction A toward the downstream side. The second facing surface 702 is a flat surface formed from the first ridge 710 that is a boundary with the first facing surface 701 toward the downstream side in the transport direction A. Further, the third facing surface 703 is configured by a concave curved surface formed toward the downstream side in the transport direction A from the second ridge 720 that is a boundary with the second facing surface 702. Furthermore, the fourth facing surface 704 includes a plane formed from the third ridge 730, which is a boundary with the third facing surface 703, toward the downstream side in the transport direction A, and the downstream side in the transport direction A following this plane. And a convex curved surface formed toward the surface.

  In the present embodiment, the facing surface 700 including the first facing surface 701, the second facing surface 702, the third facing surface 703, and the fourth facing surface 704 is, for example, shown in FIG. As described above, the pressing member 70 has a convex and curved shape that gradually rises from both axial end portions toward the axial central portion. For example, as illustrated in FIG. 9B, the first ridge 710 and the second ridge among the first ridge 710, the second ridge 720, and the third ridge 730 formed on the facing surface 700. 720 is linearly formed along the axial direction of the pressing member 70, and among these, the third ridge portion 730 which is the most downstream side in the transport direction A is axial from the axial center of the pressing member 70. It is formed in a curved shape toward both ends. From another viewpoint, it can be said that the third ridge 730 is formed on the facing surface 700 of the pressing member 70 so as to be convex and curved when viewed from the downstream side in the transport direction A.

  Next, the through hole 740 of this embodiment will be described. In the following description, the case where the pressing member 70 is provided in the image forming apparatus 1 in the orientation shown in FIG. That is, in the pressing member 70 of the present embodiment, the lower side is from the fourth facing surface 704 shown in FIG. 8 toward the first facing surface 701, the side surface 750 of the pressing member 70 is the bottom surface, and the side surface 760 is the top surface. Become.

  The through hole 740 of the present embodiment has an opening 740b (see FIG. 9A) that opens from the opening 740a (see FIG. 9B) that opens at the third facing surface 703 to the side 750 of the pressing member 70. And extends through the pressing member 70 (see FIG. 8). That is, since the through-hole 740 is inclined downward with respect to the horizontal direction, as will be described later, the lubricant passes through the pressing member 70 from the opening 740a (flows down through the through-hole 740), and the opening 740a. It is discharged out of the pressing member 70 from the opening 740b at a lower position. In addition, the through-hole 740 of this embodiment is provided in the axial direction center of the pressing member 70, and two in the axial direction both ends.

  FIG. 10 is an enlarged schematic side view of the fixing device of the present embodiment. FIG. 11 is a schematic top view of the facing surface as viewed from the upper side in FIG. Here, FIG. 10 illustrates a state before the paper P passes through the nip portion N, and FIG. 11 illustrates a state when the paper P passes through the nip portion N. Further, in FIG. 10, the vertical direction of the figure is the vertical direction as in FIG. 8.

  First, in the periphery of the nip portion N, the relationship between the pressure belt 520 and the pressure member 521 (the pressing member 70, the pressing support member 80), the lubricant supplied to the inner surface of the pressure belt 520, and the pressing member 70 The relationship with the through hole 740 provided will be described.

  The pressure belt 520 that rotates along the belt rotation direction C continuously contacts the first facing surface 701 and the second facing surface 702 (is hardly in contact with the third facing surface 703), and then the fourth facing. Contact surface 704. Further, as the pressure belt 520 rotates, the lubricant is supplied from the lubricant supply member 524 to the inner surface of the pressure belt 520, and the pressure belt 520 is placed between the pressure belt 520 and each facing surface that contacts the pressure belt 520. A lubricant is interposed between the two. This suppresses an increase in sliding resistance (coefficient of friction) between the pressure belt 520 and each facing surface in contact with the pressure belt 520, compared to a case where no lubricant is supplied to the inner surface of the pressure belt 520. Is done.

  By the way, with use of the fixing device 50, the pressure belt 520 and the like may be worn and wear powder may be generated. For example, when such wear powder accumulates on each facing surface that contacts the pressure belt 520, sliding resistance between the pressure belt 520 and each facing surface that contacts the pressure belt 520 increases. There is a case. However, in the present embodiment, when the above-described wear powder accumulates on the third facing surface 703 having a concave structure, it is suppressed that the wear powder accumulates on the facing surface that contacts the pressure belt 520. Conceivable. As a result, an increase in sliding resistance (friction coefficient) between the pressure belt 520 and each facing surface in contact with the pressure belt 520 is suppressed as compared with a pressing member that does not have a concave structure.

  In addition, excessive lubricant out of the lubricant supplied to the pressure belt 520 may flow into the third facing surface 703 that forms the recess. Then, the lubricant that has flowed to the third facing surface 703 may gelate due to the passage of time, heat from the outside, reaction with the above-mentioned wear powder, and the like. As the gelled lubricant accumulates on the third facing surface 703, it flows out to the first facing surface 701, the second facing surface 702, etc., and the pressure belt 520 and each facing surface that contacts the pressure belt 520 May increase the sliding resistance. However, in the present embodiment, the lubricant that has flowed to the third facing surface 703 by the through hole 740 that discharges the lubricant on the third facing surface 703 causes the lubricant to flow into the through hole 740 from the opening 740a on the third facing surface 703 side. And flows out of the pressing member 70 from the opening 740b at a position lower than the opening 740a. Therefore, although the fixing device 50 of the present embodiment includes the facing surface 700, the lubricant that has flowed to the third facing surface 703 is not discharged to the outside of the third facing surface 703 and enters the third facing surface 703. Compared to a fixing device using a pressing member that accumulates, gelation of the lubricant is suppressed, and an increase in sliding resistance between the pressure belt 520 and each facing surface that contacts the pressure belt 520 is suppressed. Conceivable. As a result, the fixing device 50 according to the present embodiment includes the facing surface 700, but the lubricant that has flowed to the third facing surface 703 is not discharged outside the third facing surface 703, but is inside the third facing surface 703. Compared to a fixing device using a pressing member that accumulates on the sheet P, it is considered that the occurrence of image disturbance of the image on the paper P can be suppressed.

  In the through hole 740 of the present embodiment, the position of the opening 740a (see FIG. 10B) that opens at the third facing surface 703 is not particularly limited, but the lubricant from the third facing surface 703 is not limited. It is preferable to set it to the lowest position among the third opposing surfaces 703 in terms of the discharge performance. In addition, in the through hole 740 of the present embodiment, the pressing member 70 is provided if the position of the opening 740b opposite to the opening 740a of the third facing surface 703 is lower than the opening 740a of the third facing surface 703. For example, in the case of the pressing member 70 installed in the orientation of FIG. 8, in addition to the side surface 750 serving as the bottom surface of the pressing member 70, the side surface opposite to the facing surface 700 is provided. (However, the surface located below the opening 740a), the first opposing surface 701, the second opposing surface 702, and the like may be used. In these, it is preferable to provide in the side surface 750 used as the bottom face of the pressing member 70 at the point of discharge of a lubricant.

  In the present embodiment, the side surface 750 of the pressing member 70 has been described as the bottom surface, and the side surface 760 of the pressing member 70 has been described as the upper surface, but for example, the opposing surface 700 of the pressing member 70 is the upper surface and the side surface opposite to the opposing surface 700 is the surface. When the bottom surface is used (the left to right direction in FIG. 8 is the vertical direction), the through-hole 740 is, for example, the side surface 750 of the pressing member 70 and the side surface 760 of the pressing member 70 from the opening that opens at the third facing surface 703. Or what is necessary is just to be comprised so that it may extend toward the opening part opened on the side surface on the opposite side to the opposing surface 700, and may penetrate the pressing member 70. FIG. Further, for example, when the side surface 750 of the pressing member 70 is the top surface and the side surface 760 of the pressing member 70 is the bottom surface (upward from the bottom in FIG. 8 is the vertical direction), the through hole 740 opens at the third facing surface 703. For example, it extends from the opening to a side opposite to the facing surface 700 (however, a surface located below the opening 740a) or an opening that opens at the side 760 of the pressing member 70 and penetrates the pressing member 70. What is necessary is just to be comprised. In any case, the through hole 740 of the present embodiment is configured to discharge the lubricant in the recess (third facing surface 703) from the recess through the pressing member 70 and out of the pressing member 70. That's fine.

  The hole shape (cross-sectional shape) of the through hole 740 of the present embodiment is not particularly limited, and examples thereof include a circular shape and a rectangular shape. In addition, the size of the through hole 740 according to the present embodiment may be set as appropriate in consideration of the dischargeability of the lubricant. However, the through hole 740 is preferable in terms of suppressing clogging due to the wear powder and the like. When the hole shape is circular, it preferably has a diameter of 2 mm or more and 4 mm or less, for example, and when it is rectangular, it preferably has a size of 2 mm × 5 mm, for example. Moreover, if the through-hole 740 of this embodiment inclines below with respect to a horizontal direction, the inclination-angle of the through-hole 740 will not be restrict | limited especially, However, in terms of the discharge property of a lubricant, it is horizontal. It is preferably in the range of 10 ° or more and 90 ° or less with respect to the direction. Further, the number of through holes 740 is not particularly limited and may be one or more, but three or more are preferable in terms of lubricant dischargeability.

  In the present embodiment, it is preferable to fill the through hole 740 with a foam. By filling the through hole 740 with the foam, the lubricant in the third facing surface 703 is absorbed by the foam, so that the through hole is less than the case where the through hole 740 is not filled with the foam. It is considered that the lubricant is easily discharged from the pressing member 70 from 740. Therefore, the fixing device having the foam filled in the through hole 740 includes the facing surface 700, but the lubricant that has flowed to the third facing surface 703 is discharged out of the third facing surface 703. Compared to a fixing device using a pressing member that accumulates in the third facing surface 703 instead, the gelation of the lubricant is further suppressed, and the sliding between the pressure belt 520 and each facing surface that contacts the pressure belt 520 is reduced. It is considered that the increase in dynamic resistance is suppressed. As a result, the fixing device having the foam filled in the through hole 740 is provided with the facing surface 700, but the lubricant that has flowed to the third facing surface 703 is discharged out of the third facing surface 703. It is considered that the occurrence of image disturbance on the image on the paper P can be further suppressed as compared with a fixing device using a pressing member that accumulates in the third facing surface 703 without any problems.

  Examples of the foam used in the present embodiment include foams such as urethane resin, silicone resin, and fluororesin. The foaming rate of the foam is, for example, preferably 20% or more and 70% or less, and more preferably 30% or more and 65% or less. When the foaming ratio of the foam is out of the above range, the absorbability of the lubricant may be reduced as compared with the case where the above range is satisfied.

  Next, the relationship between the heating roll 510 constituting the heating module 51 and the pressure belt 520 constituting the pressure module 52 around the nip portion N will be described. In the present embodiment, as described above, a portion of the pressing belt 520 that faces the fourth facing surface 704 of the pressing member 70 is in contact with the outer peripheral surface of the heating roll 510. Then, a portion of the pressure belt 520 that faces the fourth facing surface 704 comes into contact with the heating roll 510, so that the nip portion N is formed. In the present embodiment, in the nip portion N, the pressure on the downstream side in the transport direction A (the exit side of the paper P) is larger than the pressure on the upstream side in the transport direction A (the entrance side of the paper P). It is desirable that the shape of the fourth facing surface 704 in the pressing member 70 and the positional relationship among the heating roll 510, the pressure belt 520, and the pressing member 70 are set.

  In the present embodiment, on the upstream side in the transport direction A from the nip portion N, the outer peripheral surface of the pressure belt 520 is a first facing surface 701, a second facing surface 702, and a third facing surface provided on the pressing member 70. By the surface 703 (further, the nip portion N located on the downstream side in the transport direction A from the third facing surface 703), the inclination of the surface is changed stepwise. More specifically, the second opposing surface is larger than the angle formed by the outer peripheral surface of the pressure belt 520 at the site facing the first opposing surface 701 and the tangent line of the outer peripheral surface of the heating roll 510 facing this site. The angle formed by the outer peripheral surface of the pressure belt 520 at the portion facing 702 and the tangent line of the outer peripheral surface of the heating roll 510 facing this portion is smaller. Further, it is opposed to the third opposing surface 703 than the angle formed by the outer peripheral surface of the pressure belt 520 at the site facing the second opposing surface 702 and the tangent line of the outer peripheral surface of the heating roll 510 at the site facing this site. The angle formed by the outer peripheral surface of the pressure belt 520 at the portion to be formed and the tangent line of the outer peripheral surface of the heating roll 510 at the portion facing this portion is smaller. Therefore, in the present embodiment, a space (gap) formed between the heating roll 510 and the pressure belt 520 upstream of the nip portion N in the transport direction A is stepwise along the transport direction A. It has come to decrease. The gap between the outer peripheral surface of the heating roll 510 and the outer peripheral surface of the pressure belt 520 has such a relationship on the upstream side in the transport direction A from the nip portion N. In addition, the first opposing surface 701 and the second opposing surface 702 are provided with the first ridge 710 interposed therebetween, and the second opposing surface 702 and the third opposing surface 703 are provided with the second ridge 720 interposed therebetween. Is.

  Next, the behavior of the paper P passing through the nip portion N will be described. Here, it is assumed that the heating roll 510 is already heated by the heating element 512 (see FIG. 3), and the heating roll 510 is rotated in the roll rotation direction B as it is driven. It is assumed that the pressure belt 520 that contacts the heating roll 510 rotates in the belt rotation direction C as the heating roll 510 rotates.

  First, the leading edge of the sheet P conveyed in the conveyance direction A hits a portion of the pressure belt 520 that rotates in the belt rotation direction C that faces the first facing surface 701. When the leading end of the sheet P hits the pressure belt 520, the leading end side of the sheet P moves toward the heating roll 510 while being guided by the pressing belt 520 moving along the first facing surface 701. To go. As a result, the leading edge of the paper P abuts on the outer peripheral surface (actually the covering member 513) of the heating roll 510 that rotates in the roll rotation direction B, upstream of the nip portion N in the transport direction A. Subsequently, the transfer surface of the paper P comes into contact with the outer peripheral surface of the heating roll 510.

  At this time, the heating roll 510 is heated by the heating element 512 (see FIG. 3), and the toner present in the region of the transfer surface of the paper P that is in contact with the outer peripheral surface of the heating roll 510 is heated by the heating roll 510. It gradually melts due to the heat received from it. As a result, the paper P is in a state of sticking to the outer peripheral surface of the heating roll 510 via the toner existing on the transfer surface (toner whose adhesiveness has increased with melting).

  Then, the front end of the paper P that is conveyed while sequentially sticking to the heating roll 510 from the front end side is a portion of the pressure belt 520 that rotates in the belt rotation direction C that faces the third facing surface 703. As it passes, it begins to be sandwiched between the heating roll 510 and the pressure belt 520. Then, the front end of the paper P maintains the state sandwiched between the heating roll 510 and the pressure belt 520, and passes through the portion facing the third ridge 730. It enters into a portion facing the fourth facing surface 704, that is, the nip portion N.

  In the nip portion N, the toner image formed on the transfer surface of the paper P is obtained by applying heat using the heating roll 510 and pressurizing using the pressing member 70 to the paper P entering. And fixed on the paper P. Here, the sheet P passing through the nip portion N is applied to the sheet P passing through the nip portion N by applying more pressure on the downstream side than the upstream side in the transport direction A in the nip portion N. On the other hand, a greater force is applied on the downstream side than on the upstream side in the transport direction A. Therefore, the paper P is strongly pressed toward the heating roll 510 (covering member 513) on the most downstream side in the nip portion N, and the front end of the paper P that has passed through the nip portion N is separated from the outer peripheral surface of the heating roll 510. It takes a force toward the direction. As a result, the paper P that has passed through the nip N is separated (separated) from the outer peripheral surface of the heating roll 510 and is discharged from the fixing device 50.

  Further, in the present embodiment, it is preferable that the third ridge portion 730 is formed so as to be convex and curved when viewed from the downstream side in the transport direction A as shown in FIG. As a result, the leading edge of the paper P that enters the nip portion N from the third ridge portion 730 sequentially passes through the third ridge portion 730 from the center portion in the width direction toward both end portions in the width direction. Accordingly, the sheet P passing through the third ridge 730 is subjected to a force for pushing the sheet P outward from the both ends in the width direction from the center in the width direction toward both ends in the width direction. Compared with the case where the three ridges 730 are linear along the axial direction, the generation of wrinkles when the paper P passes through the nip N is suppressed. Moreover, in this Embodiment, although the 3rd ridge part 730 provided in the pressing member 70 was made into curved shape, it is not restricted to this, For example, it is good also as what arrange | positioned two straight lines in V shape. However, it may be linear.

  In the above description, the front end of the paper P has been described as first hitting a portion of the pressure belt 520 that faces the first facing surface 701. 2 Even if it first hits the part facing the opposite surface 702, the leading edge of the paper P reaches the heating roll 510 upstream of the nip portion N in the transport direction A.

  As described above, in the present embodiment, the sheet P conveyed toward the nip portion N is pressed along the first opposing surface 701 (or the second opposing surface 702) provided on the pressing member 70. The belt 520 is used to guide the heating roll 510 side. As a result, the paper P conveyed toward the nip portion N comes into contact with the heating roll 510 on the upstream side in the conveyance direction A from the nip portion N. Then, by bringing the paper P into contact with the heating roll 510 on the upstream side in the transport direction A from the nip portion N, the paper P is contact-heated by using the heating roll 510 before reaching the nip portion N. By adopting this configuration, compared to the case where the sheet P is contact-heated only at the nip portion N, the heat supply efficiency to the sheet P is improved, and the fixing speed is increased and the heat generation amount of the heating element 512 is reduced. May be.

  Although the embodiments of the present invention have been described above, the present invention is not construed as being limited to the above-described embodiments, and various modifications, changes, and improvements can be made, and a range that satisfies the requirements of the present invention. Needless to say, this is feasible.

  Hereinafter, although an example and a comparative example are given and the present invention is explained more concretely in detail, the present invention is not limited to the following examples.

Example 1
The test was performed using an image forming apparatus DocuPrint CM200 manufactured by Fuji Xerox Co., Ltd. under the following conditions. The fixing device mounted on the image forming apparatus is the fixing device shown in FIG. 1, and the specific configuration is as follows.

  The heating roll is formed by coating the outer peripheral surface of a cylindrical aluminum core with a thickness of 0.5 mm of silicone rubber as an elastic layer, and coating the surface of the elastic layer with a fluororesin as a release layer. It is a roll having a diameter of 20 mm. The fixing belt is made of polyimide resin as a base material (thickness 70 μm, outer diameter 20 mm), and a fluororesin layer as a release layer is coated on the outer peripheral surface of the base material with a thickness of 25 μm. Inside the heating roll, a 850 w halogen lamp was disposed as a heating source.

  A pressing member was produced by molding a PET resin. Moreover, the through-hole of the hole size of 5 mm x 2 mm was formed in the axial direction center part and both ends of the pressing member. As shown in FIG. 8, the through hole has a side surface (FIG. 8) of the pressing member positioned lower than the opening from the opening of the third facing surface (provided at the lowest position among the third facing surfaces). Extending toward the opening of the side surface 750) shown in FIG. The inclination angle of the through hole was 30 ° with respect to the horizontal direction. The pressing member was installed in the direction shown in FIGS.

  In the fixing device of Example 1, the load between the pressure belt and the heating roll (that is, the load of the nip portion N) was set to 18 kg, and the fixing temperature was set to 160 ° C. (in the vicinity of the pressing portion on the plain paper entrance side). Measured with a temperature sensor), and after passing 100,000 sheets of A4 paper (P paper manufactured by Fuji Xerox Co., Ltd.) at a paper feeding speed of 175 mm / sec, it was transferred to A4 paper (C2 paper manufactured by Fuji Xerox Co., Ltd.). A halftone 50% density image was output. As a result of visually confirming the output image, no image disturbance occurred. Further, after passing 100,000 sheets of A4 paper (P paper manufactured by Fuji Xerox Co., Ltd.) at a load of nip N of 18 kg, a fixing temperature of 160 ° C. and a paper passing speed of 175 mm / sec, A4 paper (Fuji Xerox Co., Ltd., C2 A paper image was output with a 50% halftone density. As a result of visually confirming the output image, image disturbance occurred.

(Example 2)
Example 2 is the same as the fixing device of Example 1 except that a urethane resin (EP70, manufactured by Inoac Co., Ltd.) is filled as a foam in the through hole.

  In the fixing device of Example 2, after passing 100,000 sheets of A4 paper (P paper manufactured by Fuji Xerox Co., Ltd.) at a load of 18 kg at the nip N, a fixing temperature of 160 ° C., and a paper feeding speed of 175 mm / sec, A4 paper ( An image having a halftone density of 50% was output to Fuji Xerox Co., Ltd. (C2 paper). As a result of visually confirming the output image, no image disturbance occurred. Further, after passing 100,000 sheets of A4 paper (P paper manufactured by Fuji Xerox Co., Ltd.) at a load of nip N of 18 kg, a fixing temperature of 160 ° C. and a paper passing speed of 175 mm / sec, A4 paper (Fuji Xerox Co., Ltd., C2 The image quality of halftone 50% density was output on paper. As a result of visually confirming the output image, no image disturbance occurred.

(Comparative example)
The comparative example is the same as the fixing device of Example 1 except that no through hole is provided.

  In the fixing device of the comparative example, after passing 100,000 sheets of A4 paper (P paper manufactured by Fuji Xerox Co., Ltd.) at a load of 18 kg at the nip N, a fixing temperature of 160 ° C., and a paper feeding speed of 175 mm / sec, A4 paper (Fuji A halftone 50% density image was output to Xerox C2 paper. As a result of visually confirming the output image, image disturbance occurred.

  As described above, in the fixing device of Example 1, the occurrence of image distortion was suppressed as compared with the fixing device of the comparative example. This is because the fixing device according to the first embodiment in which the lubricant in the recess is discharged out of the pressing member through the through hole is not provided with the through hole and the fixing in the comparative example in which the lubricant is accumulated in the recess. This is considered to be because the gelation of the lubricant in the recess was suppressed by the apparatus, and the increase in sliding resistance between the pressure belt and the pressing member was suppressed. Further, in the fixing device of Example 2, the occurrence of image distortion was suppressed as compared with the fixing device of Example 1 and the fixing device of Comparative Example 1. This is because, in the fixing device of Example 2, since the lubricant in the recess is absorbed by the foam (urethane resin) provided in the through hole, the fixing of Example 1 in which the foam is not provided in the through hole. This is probably because the lubricant is more easily discharged out of the pressing member as compared with the device.

  DESCRIPTION OF SYMBOLS 1 Image forming apparatus, 10 Image forming part, 11 Photosensitive drum, 12 Charging apparatus, 13 Exposure apparatus, 14 Developing apparatus, 15 Primary transfer apparatus, 20 Intermediate transfer belt, 30 Secondary transfer apparatus, 40 Paper supply part, 50 Fixing Equipment 51 Heating module 52 Pressure module 53 Support module 60 Control part 70 Pressing member 71 Groove part 73 Projection part 80 Pressing support member 81 Pressing part 510 Heating roll 520 Pressure belt 521 Addition Pressure member, 522 Belt holding member, 523 Restriction member, 524 Lubricant supply member, 531 Roll support member, 532 Belt support member, 533 Slide bearing, 534 Tensile spring, 700 Opposing surface, 701 First opposing surface, 702 Second opposing Surface, 703 third facing surface, 704 fourth facing surface, 710 first ridge, 720 2nd ridge part, 730 3rd ridge part, 740 Through-hole, 740a, 740b Opening part, 750, 760 Side surface.

Claims (3)

A first rotating body;
A second rotating body disposed in contact with the outer surface of the first rotating body;
A pressing member disposed inside the second rotating body,
The pressing member is in contact with the inner surface of the second rotating body, presses the second rotating body against the first rotating body, and passes the recording medium between the first rotating body and the second rotating body. A first pressing portion that forms a nip portion and an inner surface of the second rotating body, and the second rotating body is pushed toward the first rotating body on the upstream side of the nip portion in the conveyance direction of the recording medium. Provided with a second pressing portion and a space away from the second rotating body on the upstream side in the transport direction of the recording medium from the first pressing portion and on the downstream side in the transport direction of the recording medium from the second pressing portion. And a through hole for discharging the lubricant from the recess through the inside of the pressing member to the outside of the pressing member when the lubricant supplied to the inner surface of the second rotating body flows into the recess. And a fixing device.   The fixing device according to claim 1, further comprising a foam filled in the through hole. An image carrier, a latent image forming unit for forming a latent image on the surface of the image carrier, a developing unit for developing the latent image using a developer for developing an electrostatic image to form a toner image, and the toner Transfer means for transferring an image to a recording medium, and fixing means for fixing the toner image to the recording medium,
The image forming apparatus according to claim 1, wherein the fixing unit is the fixing device according to claim 1.

Images