JP2016177193A - Belt member, fixation device, and image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a belt member for suppressing leak of a lubricant from an end of the belt member, and provide a fixation device and image formation device including the belt member.SOLUTION: A belt member 62 includes a cylindrical substrate 621, and a coating layer disposed on the outer peripheral surface of the substrate 621. The coating layer includes a fluororesin tube 622 serving as an outermost layer of the coating layer. The end of the fluororesin tube 622 is folded to the inner peripheral surface side of the substrate 621. The terminal of the folded portion 623 is located on the axial outside of a pressure pad 64 disposed on the inner peripheral surface side of the substrate 621.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a belt member, 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, for example, a photosensitive member (photosensitive drum) formed in a drum shape is charged, and the photosensitive drum is controlled by light controlled based on image information. An electrostatic latent image is formed on the photosensitive drum by exposure, and the electrostatic latent image is converted into a visible image (toner image) with toner, and the toner image is transferred from the photosensitive drum to a recording medium such as paper. Thereafter, the toner image is fixed on the recording medium by a fixing device.

  As the fixing device, for example, a rotatable rotating member, a belt member that contacts the rotating member and rotates according to the rotating member, and is arranged to face the rotating member via the belt member. A pressing member that presses from the inner peripheral surface of the member toward the rotating member and forms a nip portion through which a recording medium such as paper passes between the fixing member and the rotating member, and the recording medium is placed in the nip portion. A fixing device (referred to as “free belt nip method”) that fixes a toner image on a recording medium by passing the recording medium is known.

  As such a fixing device, there is known a fixing device configured such that a lubricant exists between the belt member and the pressing member for the purpose of reducing the frictional resistance between the belt member and the pressing member. Yes.

  Patent Document 1 discloses a heating member and a pressure member, at least one of which is a belt member, a belt guide member that rotatably supports both end portions of the belt member, a pressing member, and oil ( And a fixing device provided with oil leakage prevention means for preventing oil leakage on at least one of the outer peripheral surface of the belt guide member and the inner peripheral surface of the belt member. Yes.

  Patent Document 2 includes a rotating member, a belt member, a pressing member, and a low friction member that reduces friction between the belt member and the pressure member. A fixing device is disclosed in which a step that increases toward the belt member side is formed in a region including the portion.

  Patent Document 3 includes a belt member, a pressing member, and a belt guide member, and protrudes outward in the diametrical direction of the belt member at a position that is axially outer than the pressing member at the nip portion of the outer peripheral surface of the belt member. Thus, a fixing device having a ring-shaped lubricant regulating member that is fixed is disclosed.

JP 2002-357968 A JP 2006-72218 A JP 2012-118225 A

  An object of the present invention is to provide a belt member that suppresses leakage of lubricant from an end portion of the belt member, a fixing device including the belt member, and an image forming apparatus.

  The invention according to claim 1 includes a cylindrical base material and a coating layer disposed on an outer peripheral surface of the base material, and the coating layer includes a fluororesin tube serving as an outermost layer of the coating layer. And an end portion of the fluororesin tube is folded back to the inner peripheral surface side of the base material, and an end of the folded portion is axially outer than a pressing member disposed on the inner peripheral surface side of the base material. It is the belt member which is located.

  The invention according to claim 2 is the belt member according to claim 1, wherein a gap is formed between a terminal end of the folded portion and an inner peripheral surface of the base material.

  The invention according to claim 3 is the belt member according to claim 1, wherein the end of the folded portion protrudes radially inward of the base material.

  The invention according to claim 4 is a rotatable rotating member, the belt member according to any one of claims 1 to 3 that is movable while contacting the rotating member, and the rotation via the belt member. A pressing member that is arranged to face the member and presses the belt member toward the rotating member to form a nip portion through which a recording medium passes between the rotating member and the belt member; The fixing device is provided.

  According to a fifth aspect of the present invention, there is provided an image holding member, a charging unit that charges the surface of the image holding member, a latent image forming unit that forms an electrostatic latent image on the charged surface of the image holding member, The fixing device according to claim 4, wherein a developing unit that develops the electrostatic latent image with a developer to form a toner image, a transfer unit that transfers the toner image to a recording medium, and the toner image is fixed to the recording medium. And an image forming apparatus.

  According to the first aspect of the present invention, the fluororesin tube includes a cylindrical base material and a coating layer disposed on the outer peripheral surface of the base material, and the coating layer is the outermost layer of the coating layer. A belt member that suppresses leakage of lubricant from the end of the belt member as compared to a belt member in which the end of the fluororesin tube is not folded back to the inner peripheral surface side of the base material. Provided.

  According to the invention which concerns on Claim 2, compared with the belt member which the termination | terminus of the said folding | turning part is contacting the internal peripheral surface of the said base material, it suppresses that a lubricant leaks from the edge part of a belt member. A belt member is provided.

  According to the invention of claim 3, the belt that suppresses leakage of the lubricant from the end portion of the belt member as compared with a belt member in which the terminal end of the folded portion does not protrude radially inward of the base material. A member is provided.

  According to the invention which concerns on Claim 4, it is comprised from the cylindrical base material and the coating layer arrange | positioned at the outer peripheral surface of the said base material, and the said coating layer becomes the outermost layer of the said coating layer. And the leakage of lubricant from the end of the belt member is suppressed compared to the case where a belt member is used in which the end of the fluororesin tube is not folded back to the inner peripheral surface side of the base material. A fixing device is provided.

  According to the invention which concerns on Claim 5, it is comprised from the cylindrical base material and the coating layer arrange | positioned at the outer peripheral surface of the said base material, and the said coating layer becomes the outermost layer of the said coating layer. And the leakage of lubricant from the end of the belt member is suppressed compared to the case where a belt member is used in which the end of the fluororesin tube is not folded back to the inner peripheral surface side of the base material. An image forming apparatus is provided.

1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a side sectional view illustrating an example of a configuration of a fixing device used in the image forming apparatus according to the present exemplary embodiment. It is a side sectional view showing an example of a pressure belt used in the fixing device of the present embodiment. (A) is a schematic cross-sectional view showing an example of the configuration of the pressure belt as viewed from the direction in which the recording medium is conveyed, and (B) is a partially enlarged schematic cross-sectional view of the pressure belt shown in FIG. It is. FIGS. 4A to 4C are partially enlarged schematic cross-sectional views illustrating another example of the configuration of the pressure belt as viewed from the direction in which the recording medium is conveyed. FIG. 6 is a schematic cross-sectional view illustrating another example of the configuration of the pressure belt as viewed from the direction in which the recording medium is conveyed.

  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.

  FIG. 1 is a schematic configuration diagram illustrating an example of a configuration of an image forming apparatus according to the present embodiment. The image forming apparatus 100 shown in FIG. 1 includes a plurality of image forming units 1Y, 1M, 1C, and 1K on which toner images of respective color components are formed by electrophotography, and the image forming units 1Y, 1M, 1C, and 1K. The primary transfer unit 10 that sequentially transfers (primary transfer) each color component toner image formed by the above process to the intermediate transfer belt 15 and the superimposed toner image transferred onto the intermediate transfer belt 15 are collectively transferred to a recording medium (recording paper) P. A secondary transfer unit 20 for (secondary transfer) and a fixing device 60 for fixing the secondary transferred image on the recording medium P are provided. Moreover, it has the control part 40 which controls operation | movement of each apparatus (each part).

  In this embodiment, each of the image forming units 1Y, 1M, 1C, and 1K includes a charger 12 that charges the photosensitive drum 11 around the photosensitive drum 11 that rotates in the direction of arrow A, and a photosensitive drum. A laser exposure unit 13 for writing an electrostatic latent image on the image 11 (in FIG. 1, the exposure beam is indicated by a symbol Bm), and each color component toner is accommodated so that the electrostatic latent image on the photosensitive drum 11 can be transferred with the toner. A developing device 14 for visualizing, a primary transfer roll 16 for transferring each color component toner image formed on the photosensitive drum 11 to the intermediate transfer belt 15 in the primary transfer unit 10, and residual toner on the photosensitive drum 11. An electrophotographic device such as a drum cleaner 17 is removed in order. These image forming units 1Y, 1M, 1C, and 1K are arranged substantially linearly in the order of yellow (Y), magenta (M), cyan (C), and black (K) from the upstream side of the intermediate transfer belt 15. Has been.

The intermediate transfer belt 15 which is an intermediate transfer member is constituted by a film endless belt (endless belt) in which an appropriate amount of an antistatic agent such as carbon black is contained in a resin such as polyimide or polyamide. The volume resistivity of the intermediate transfer belt 15 is formed to be, for example, 10 ⁶ Ωcm or more and 10 ¹⁴ Ωcm or less, and the thickness thereof is, for example, about 0.1 mm. The intermediate transfer belt 15 is circulated (rotated) by various rolls at a predetermined speed in the direction B shown in FIG. In the present embodiment, as various rolls, a drive roll 31 that is driven by a motor (not shown) having excellent constant speed and rotates the intermediate transfer belt 15 and extends along the arrangement direction of the photosensitive drums 11. Provided in the secondary transfer unit 20 are a support roll 32 that supports the intermediate transfer belt 15, a tension roll 33 that functions as a correction roll that applies tension to the intermediate transfer belt 15 and prevents meandering of the intermediate transfer belt 15, and the like. And a cleaning backup roll 34 provided in a cleaning unit that scrapes off residual toner on the intermediate transfer belt 15.

In the present embodiment, the primary transfer unit 10 includes a primary transfer roll 16 that is disposed to face the photosensitive drum 11 with the intermediate transfer belt 15 interposed therebetween. The primary transfer roll 16 includes, for example, a shaft (not shown) and a sponge layer (not shown) as an elastic layer fixed around the shaft. The shaft is, for example, a cylindrical bar made of a metal such as iron or SUS. The sponge layer is made of, for example, a blend rubber of acrylonitrile-butadiene rubber (NBR), styrene-butadiene rubber (SBR), and ethylene-propylene-diene rubber (EPDM) containing a conductive agent such as carbon black, and has a volume resistivity. Is a sponge-like cylindrical roll of 10 ⁷ Ωcm or more and 10 ⁹ Ωcm or less, for example. The primary transfer roll 16 is disposed in pressure contact with the photosensitive drum 11 with the intermediate transfer belt 15 interposed therebetween. Further, the primary transfer roll 16 is opposite to the toner charging polarity (negative polarity; the same applies hereinafter). A polarity voltage (primary transfer bias) is applied. As a result, the toner images on the respective photosensitive drums 11 are sequentially electrostatically attracted to the intermediate transfer belt 15 so as to form superimposed toner images on the intermediate transfer belt 15.

In the present embodiment, the secondary transfer unit 20 includes a secondary transfer roll 22 disposed on the toner image holding surface side of the intermediate transfer belt 15 and a backup roll 25. The backup roll 25 is composed of a tube of EPDM rubber and NBR blend rubber in which, for example, carbon is dispersed, and the inside is made of, for example, EPDM rubber. The surface resistivity is formed to be, for example, 10 ⁷ Ω / □ or more and 10 ¹⁰ Ω / □ or less, and the hardness is set to, for example, 70 ° (Asker C: manufactured by Kobunshi Keiki Co., Ltd.). Has been. The backup roll 25 is disposed on the back surface side of the intermediate transfer belt 15 to constitute a counter electrode of the secondary transfer roll 22, and a metal-made power supply roll 26 for applying a secondary transfer bias is disposed in contact therewith.

In the present embodiment, the secondary transfer roll 22 includes, for example, a shaft (not shown) and a sponge layer (not shown) as an elastic layer fixed around the shaft. The shaft is, for example, a cylindrical rod made of metal such as iron or SUS. The sponge layer is made of, for example, a blended rubber of NBR, SBR, and EPDM containing a conductive agent such as carbon black, and has a volume resistivity of 10 ⁷ Ωcm or more and 10 ⁹ Ωcm or less, such as a cylindrical shape such as a sponge. It is a roll. The secondary transfer roll 22 is disposed in pressure contact with the backup roll 25 with the intermediate transfer belt 15 interposed therebetween. Further, the secondary transfer roll 22 is grounded and a secondary transfer bias is formed between the secondary transfer roll 22 and the backup roll 25. Then, the toner image is secondarily transferred onto the recording medium P conveyed to the secondary transfer unit 20.

  Further, in the present embodiment, residual toner, paper dust, and the like on the intermediate transfer belt 15 after the secondary transfer are removed on the downstream side of the secondary transfer unit 20 of the intermediate transfer belt 15, and the surface of the intermediate transfer belt 15 is removed. An intermediate transfer belt cleaner 35 for cleaning the toner is detachably provided. Further, in the present embodiment, a reference sensor (home position sensor) 42 that generates a reference signal for taking an image forming timing in each of the image forming units 1Y, 1M, 1C, and 1K on the upstream side of the yellow image forming unit 1Y. Is arranged. Further, an image density sensor 43 for adjusting image quality is disposed on the downstream side of the black image forming unit 1K. The reference sensor 42 recognizes a mark provided on the back side of the intermediate transfer belt 15 and generates a reference signal. In response to an instruction from the control unit 40 based on the recognition of the reference signal, each image forming unit 1Y, 1M, 1C, and 1K are configured to start image formation.

  Furthermore, in the image forming apparatus 100 of the present embodiment, as a paper transport system, for example, a paper tray 50 that accommodates the recording medium P, and a pickup roll 51 that takes out and transports the recording medium P accumulated in the paper tray 50, The transport roll 52 that transports the recording medium P fed by the pickup roll 51, the transport chute 53 that feeds the recording medium P transported by the transport roll 52 to the secondary transfer unit 20, and the secondary transfer roll 22 A transport belt 55 that transports the recording medium P transported after the next transfer to the fixing device 60 and a fixing inlet guide 56 that guides the recording medium P to the fixing device 60 are provided.

  Next, a basic image forming process of the image forming apparatus 100 according to the present embodiment will be described.

  In the image forming apparatus 100 as shown in FIG. 1, image data output from an image reading apparatus (IIT) (not shown), a personal computer (PC) (not shown) or the like is received by an image processing apparatus (IPS) ( After the image processing is performed by the image forming unit 1Y, 1M, 1C, and 1K, an image forming operation is performed. Specifically, in the IPS, input reflectance data is subjected to predetermined image editing such as shading correction, position shift correction, brightness / color space conversion, gamma correction, frame deletion, color editing, moving editing, and the like. Image processing is performed. The image data that has been subjected to image processing is converted into color material gradation data of four colors Y, M, C, and K, and is output to the laser exposure unit 13.

  The laser exposure unit 13 irradiates, for example, an exposure beam Bm emitted from a semiconductor laser to the photosensitive drums 11 of the image forming units 1Y, 1M, 1C, and 1K according to the input color material gradation data. . In each of the photosensitive drums 11 of the image forming units 1Y, 1M, 1C, and 1K, the surface is charged by the charger 12, and then the surface is scanned and exposed by the laser exposure unit 13 to form an electrostatic latent image. The formed electrostatic latent images are developed as toner images of respective colors Y, M, C, and K by the respective image forming units 1Y, 1M, 1C, and 1K. The toner images formed on the photosensitive drums 11 of the image forming units 1Y, 1M, 1C, and 1K are transferred onto the intermediate transfer belt 15 in the primary transfer unit 10 where the photosensitive drums 11 and the intermediate transfer belt 15 are in contact with each other. Transcribed. More specifically, in the primary transfer unit 10, a voltage (primary transfer bias) having a polarity opposite to the charging polarity (negative polarity) of the toner is applied to the base material of the intermediate transfer belt 15 by the primary transfer roll 16. Primary transfer is performed by sequentially superposing the toner images on the surface of the intermediate transfer belt 15.

  After the toner images are sequentially primary transferred onto the surface of the intermediate transfer belt 15, the intermediate transfer belt 15 moves and the toner image is conveyed to the secondary transfer unit 20. When the toner image is conveyed to the secondary transfer unit 20, in the paper conveyance system, the pickup roll 51 rotates in accordance with the timing at which the toner image is conveyed to the secondary transfer unit 20, so Recording medium P, which is a sheet of paper, is supplied. The recording medium P supplied by the pickup roll 51 is transported by the transport roll 52 and reaches the secondary transfer unit 20 via the transport chute 53. Before reaching the secondary transfer unit 20, the recording medium P is temporarily stopped, and a registration roll (not shown) rotates in accordance with the movement timing of the intermediate transfer belt 15 on which the toner image is held. The position of the medium P and the position of the toner image are aligned.

  In the secondary transfer unit 20, the secondary transfer roll 22 is pressed against the backup roll 25 via the intermediate transfer belt 15. At this time, the recording medium P conveyed at the same timing is sandwiched between the intermediate transfer belt 15 and the secondary transfer roll 22. At this time, when a voltage (secondary transfer bias) having the same polarity as the toner charging polarity (negative polarity) is applied from the power supply roll 26, a transfer electric field is formed between the secondary transfer roll 22 and the backup roll 25. Is done. The unfixed toner image held on the intermediate transfer belt 15 is collectively electrostatically transferred onto the recording medium P by the secondary transfer unit 20 pressed by the secondary transfer roll 22 and the backup roll 25. The

  Thereafter, the recording medium P on which the toner image has been electrostatically transferred is transported as it is while being peeled off from the intermediate transfer belt 15 by the secondary transfer roll 22, and is provided downstream of the secondary transfer roll 22 in the paper transport direction. It is conveyed to the conveyor belt 55. On the conveyance belt 55, the recording medium P is conveyed to the fixing device 60 in accordance with the optimum conveyance speed in the fixing device 60. The unfixed toner image on the recording medium P conveyed to the fixing device 60 is fixed on the recording medium P by being subjected to a fixing process with heat and pressure by the fixing device 60, as will be described later. Then, the recording medium P on which the fixed image is formed is conveyed to a paper discharge placement unit provided in a discharge unit of the image forming apparatus.

  On the other hand, after the transfer to the recording medium P is completed, residual toner or the like remaining on the intermediate transfer belt 15 is conveyed to the cleaning unit as the intermediate transfer belt 15 rotates, and the cleaning backup roll 34 and the intermediate transfer belt cleaner. It is removed from the intermediate transfer belt 15 by 35.

  Next, the fixing device 60 used in the image forming apparatus 100 according to the present embodiment will be described with reference to the drawings. However, the present invention is not limited to the following embodiment.

  FIG. 2 is a side sectional view showing an example of the configuration of the fixing device used in the image forming apparatus according to the present embodiment. A fixing device 60 shown in FIG. 2 includes a fixing roll 61 as an example of a rotatable rotating member, a pressure belt 62 as an example of a belt member that moves while being in contact with the fixing roll 61, and a pressure belt 62. The pressure belt 62 is pressed toward the fixing roll 61 and a nip portion N through which the recording medium P passes is formed between the fixing roll 61 and the pressure belt 62. The main part is comprised by the pressure pad 64 as an example of the press member to perform.

  The fixing roll 61 shown in FIG. 2 is a cylindrical roll configured by laminating an elastic body layer 612 and a release layer 613 around a core (cylindrical cored bar) 611 made of metal or the like, and is rotatable. It is supported. Further, for example, a halogen heater 66 is provided inside the fixing roll 61 as a heating source. A temperature sensor 69 for controlling the temperature of the roll surface is provided around the fixing roll 61. For example, the controller 40 of the image forming apparatus 100 shown in FIG. 1 controls the lighting of the halogen heater 66 based on the temperature measurement value by the temperature sensor 69, and the surface temperature of the fixing roll 61 is set to a predetermined temperature (for example, 175 ° C.).

  The pressure belt 62 shown in FIG. 2 is rotated by a pressure pad 64 and a belt traveling guide 63 disposed inside the pressure belt 62, and meandering prevention members disposed at both ends of the pressure belt 62, which will be described later. It is supported freely. Then, it contacts the fixing roll 61 at the nip portion N, and rotates in the direction of the arrow in accordance with the fixing roll 61 (for example, a surface speed of 250 mm / second). The pressure belt 62 shown in FIG. 2 is preferably an endless belt without a seam formed in a cylindrical shape or the like so that a defect due to the seam does not occur in the output image. Details of the pressure belt 62 will be described later.

  The pressure pad 64 shown in FIG. 2 is attached to a holder 65 made of metal or the like inside the pressure belt 62. The pressure pad 64 has a function of pressurizing the fixing roll 61 via the pressure belt 62 and forming a nip portion N through which the recording medium P can pass between the pressure belt 62 and the fixing roll 61. As long as the shape, structure, etc. are not particularly limited. However, from the viewpoint of smoothing the toner image surface to give image gloss and improving the peelability of the recording medium P, the pressure of the nip portion N is higher on the recording medium discharge side than on the recording medium entry side. It is desirable to have a shape and structure. The pressure pad 64 is, for example, a pre-nip member for securing a wide nip portion N on the inlet side (upstream side) of the nip portion N, and on the fixing roll surface on the outlet side (downstream side) of the nip portion N. A peeling nip member for forming a down curl on the recording medium P by applying distortion (dent) may be arranged.

  The belt traveling guide 63 shown in FIG. 2 is attached to the holder 65 inside the pressure belt 62, and is configured so that the pressure belt 62 moves around along the outer peripheral surface of the belt traveling guide 63. Since the belt running guide 63 rubs against the inner peripheral surface of the pressure belt 62, the belt running guide 63 is preferably formed of a material having a small static friction coefficient. Further, it is desirable that the belt traveling guide 63 is formed of a material having low thermal conductivity so that it is difficult to remove heat from the pressure belt 62.

  A lubricant application member 67 is disposed on the holder 65. The lubricant application member 67 is disposed so as to contact the inner peripheral surface of the pressure belt 62, and a lubricant such as amino-modified silicone oil is supplied to the inner peripheral surface of the pressure belt 62.

  A sliding member (not shown) is provided between the inner peripheral surface of the pressure belt 62 and the pressure pad 64 for the purpose of reducing the frictional resistance between the inner peripheral surface of the pressure belt 62 and the pressure pad 64. It may be provided. The sliding member is disposed over the entire area of the nip portion N or at least partially along the rotation direction of the pressure belt 62.

  FIG. 3 is a side sectional view showing an example of a pressure belt used in the fixing device of the present embodiment. The pressure belt 62 shown in FIG. 3 has a cylindrical base material 621 and a coating layer coated on the outer peripheral surface of the base material 621. In the pressure belt 62 shown in FIG. 3, the coating layer coated on the outer peripheral surface of the base material 621 is a fluororesin tube 622.

  4A is a schematic cross-sectional view showing an example of the configuration of the pressure belt as viewed from the direction in which the recording medium is conveyed, and FIG. 4B is a diagram of the pressure belt shown in FIG. It is a partially expanded schematic sectional view. As shown in FIGS. 4A and 4B, both end portions of the fluororesin tube 622 are folded back to the inner peripheral surface side of the base material 621, and the end of the folded portion 623 is axially outside the pressure pad 64. Is located. The folded portion 623 of the fluororesin tube 622 covers a part of the end surface and the inner peripheral surface of the base material 621. Further, the pressure pad 64 is disposed between the terminal end of one folded portion 623 of the fluororesin tube 622 and the terminal end of the other folded portion 623. And the level | step difference which protruded with respect to the internal peripheral surface of the base material 621 pressed by the pressure pad 64 is formed by the folding | returning part 623 of the fluororesin tube 622. FIG. In the pressure belt 62 shown in FIG. 4, the thickness of the folded portion 623 of the fluororesin tube 622 becomes the height of the step protruding from the inner peripheral surface of the base material 621.

  As shown in FIGS. 4A and 4B, the fixing device 60 is provided with meandering prevention members 70 at both ends of the pressure belt 62. The meandering prevention member 70 has a flange portion 72 and an insertion portion 74 as shown in FIG. The insertion portion 74 is inserted from both ends of the pressure belt 62 and is fixedly installed at both ends of the holder 65. The flange portions 72 are arranged in a state of being spaced apart from each other at a constant distance so as to abut against the end face of the pressure belt 62 when meandering.

  As shown in FIG. 4A, the outer peripheral surface of the insertion portion 74 and the folded portion 623 of the fluororesin tube 622 are in contact with each other, and the meandering prevention member 70 connects both end portions of the pressure belt 62 to the inner peripheral surface. Support from the side. In FIG. 4B, there are gaps between the pressure belt 62 and the meandering prevention member 70, the pressure belt 62 and the pressure pad 64, and the pressure belt 62 and the belt running guide 63. The pressure belt 62 and the above members are actually in contact with each other, and no gap is formed. Although not shown, a holding portion is provided on the opposite side of the insertion portion 74 with respect to the flange portion 72, the holding portion is held by a fixing portion in the fixing device, and the meandering prevention member 70 is fixed. Has been. The meandering prevention member 70 is formed of, for example, a heat resistant resin such as PPS, PET, PBT, or LCP, or a material to which a filler for lowering durability or a friction coefficient is added.

  The operation of the fixing device 60 shown in FIG. 2 will be described.

  In the fixing device 60 shown in FIG. 2, the fixing roll 61 is connected to a drive motor (not shown) and rotates in the direction of the arrow, and the pressure belt 62 also rotates in the direction of the arrow following this rotation. The recording medium P on which the toner image has been electrostatically transferred in the secondary transfer unit 20 of the image forming apparatus shown in FIG. 1 is formed by the fixing roll 61 and the pressure belt 62 being pressed against each other by a conveying means (not shown). It is conveyed to the nip portion N. Then, when the recording medium P passes through the nip portion N, the toner image on the recording medium P is subjected to pressure acting on the nip portion N, heat supplied from the fixing roll 61, etc. The toner image is fixed on the recording medium P. The recording medium P after fixing passes through the nip portion N, is peeled off from the fixing roll 61, and is discharged from the fixing device 60. In this way, the fixing process is performed. For example, when the frictional force from the fixing roll 61 becomes non-uniform in the width direction due to variations in component dimensions or the recording medium P passing through the nip portion N, the width of the pressure belt 62 is increased. There is a case in which a so-called belt walk is generated in which a force moving in the direction (axial direction) works and is shifted to either end. However, in this embodiment, even if the pressure belt 62 meanders in the axial direction, the end portions of the pressure belt 62 come into contact with the flange portions 74 of the meander prevention member 70 provided at both ends of the pressure belt 62. Therefore, the meandering of the pressure belt 62 is suppressed as compared with the case where the meandering prevention member 70 is not installed.

  By the way, in general, the fixing device is configured to press the pressure belt against the surface of the fixing roll with the pressure pad. Therefore, when the sliding resistance between the pressure belt and the pressure pad increases, the pressure belt In some cases, the driving torque increases, and the stress acting on the fixing roll, that is, the driving torque increases. As a result, there is a concern that the pressure belt may be worn or thinned, and the gear and core of the fixing roll may be damaged. In such a case, the load on the drive motor also increases, and more power may be required. Furthermore, if the frictional force between the pressure belt and the pressure pad becomes too large to be ignored compared to the driving force of the pressure belt by the fixing roll, slipping may occur between the fixing roll and the pressure belt, which is undecided. When the recording medium P holding the toner image is passed through the nip portion N, an image shift may be caused in the toner image to be fixed.

  In order to solve the above problem, there is a technique of reducing the sliding resistance between the pressure belt and the pressure pad by supplying a lubricant between the pressure belt and the pressure pad. However, since the pressure belt rotates while being pressed by the pressure pad, the lubricant supplied between the pressure belt and the pressure pad may leak from the axial end of the pressure belt. is there. As a result, for example, when the fixing device is used for a long time, the amount of lubricant between the pressure belt and the pressure pad is insufficient, the resistance between the pressure belt and the pressure pad increases, and the fixing roll The drive torque may increase early. Further, when the lubricant leaks from the end of the pressure belt, the lubricant turns to the outer peripheral surface side (the side through which the recording medium P passes) of the pressure belt, and is fixed to the pressure belt at the nip portion N. There are cases where slipping occurs between the roll and the lubricant adheres to the recording medium P passing through the nip portion N, and stains may occur.

  However, as described above, the pressure belt 62 of the present embodiment is formed with a step that protrudes from the inner peripheral surface of the base material 621 pressed by the pressure pad 64 by the folded portion 623 of the fluororesin tube 622. Therefore, it is considered that the lubricant that flows out from the end of the pressure belt 62 is blocked by the step. Therefore, the pressure belt 62 of the present embodiment has a lubricant from the end of the pressure belt as compared with the pressure belt in which the end of the fluororesin tube is not folded back to the inner peripheral surface side of the base material. Is prevented from leaking. In the fixing device 60 of the present embodiment, since leakage of the lubricant from the end of the pressure belt 62 is suppressed, an increase in sliding resistance between the pressure belt 62 and the pressure pad 64 is suppressed, and It is considered that the occurrence of slippage between the pressure belt 62 and the fixing roll 61 due to the leakage of the lubricant and the occurrence of a stain on the recording medium P due to the adhesion of the lubricant are suppressed. Furthermore, since leakage of the lubricant from the end of the pressure belt 62 is suppressed, a large amount of lubricant is supplied to the inner peripheral surface of the pressure belt 62, so that the pressure belt 62, the pressure pad 64, Since the lubricant layer is formed during this period, it is considered that the initial slip resistance is also reduced.

  In addition, the pressurizing belt 62 of the present embodiment has a fluororesin tube folded portion because the folded portion 623 of the fluororesin tube 622 is in contact with the insertion portion 74 inserted into the pressure belt 62. The amount of wear of the pressure belt 62 is reduced as compared with a pressure belt in which a base material 621 that is generally made of a material having a higher friction coefficient than fluororesin is in contact with the insertion portion 74. Conceivable. Further, when the pressure belt 62 rotates according to the rotation of the fixing roll 61, the pressure belt 62 usually deforms along the curvature of the fixing roll 61 in the nip portion N, but the folded portion 623 has a low elastic modulus fluororesin tube 622. Therefore, it is considered that the pressure belt 62 smoothly follows the shape change at the nip portion N of the pressure belt 62 and hardly affects the rotation of the pressure belt 62.

  5A to 5C are partially enlarged schematic cross-sectional views illustrating another example of the configuration of the pressure belt as viewed from the direction in which the recording medium is conveyed. 5A to 5C, there are gaps between the pressure belt 62 and the meandering prevention member 70, the pressure belt 62 and the pressure pad 64, and the pressure belt 62 and the belt travel guide 63. In order to clarify the configuration of each member, the pressure belt 62 and these members are actually in contact with each other, and no gap is formed. In the pressure belt 62 shown in FIG. 5A, the end of the folded portion 623 of the fluororesin tube 622 and the inner peripheral surface side of the substrate 621 are separated from each other, and the end of the folded portion 623 and the inside of the substrate 621 are separated. A gap 624 is formed between the peripheral surface and the peripheral surface. By forming such a gap portion 624, the lubricant that is about to leak from both ends of the pressure belt 62 is blocked by the gap portion 624, so that the pressure does not have a folded portion of the fluororesin tube. Compared with the belt, leakage of the lubricant from the end of the pressure belt 62 is further suppressed. 5B and 5C has a protruding portion 625 in which the end of the folded portion 623 of the fluororesin tube 622 protrudes inward in the radial direction of the base material 621. The protruding portion 625 shown in FIG. 5B is formed by raising the end of the folded portion 623 of the fluororesin tube 622 with respect to the base material 621. Further, the protruding portion 625 shown in FIG. 5C is formed by bending the end of the folded portion 623 of the fluororesin tube 622. By forming such a protruding portion 625, the lubricant that is about to leak from the end of the pressure belt 62 is blocked by the protruding portion 625, so that the end of the folded portion of the fluororesin tube is the diameter of the base material. Compared with the case where a pressure belt that does not protrude inward in the direction is used, leakage of the lubricant from the end portion of the pressure belt 62 is further suppressed.

  Hereinafter, members constituting the fixing device 60 will be described.

  The core 611 of the fixing roll 61 is formed of, for example, a metal or alloy having high thermal conductivity such as iron, aluminum (for example, A-5052 material), SUS, or copper, ceramics, or fiber reinforced metal (FRM).

  Examples of the material of the elastic layer 612 of the fixing roll 61 include elastic bodies such as rubber and elastomer whose rubber hardness is about 15 ° to 45 ° in terms of JIS-A hardness, and more specifically, silicone rubber, Examples thereof include fluororubber. Of these, silicone rubber is preferred from the viewpoints of low surface tension and excellent elasticity. Examples of such silicone rubber include RTV (room temperature vulcanization) silicone rubber, HTV (high temperature vulcanization) silicone rubber, and the like. Specifically, dimethyl silicone rubber (MQ) ), Methyl vinyl silicone rubber (VMQ), methyl phenyl silicone rubber (PMQ), fluorosilicone rubber (FVMQ), and the like. These may be used alone or in combination of two or more.

  The thickness of the elastic layer 612 is not particularly limited, but is, for example, 3 mm or less, and preferably in the range of 0.5 mm to 1.5 mm. There is no restriction | limiting in particular as a method of forming the elastic body layer 612 in the surface of the core 611, For example, a well-known coating method, a shaping | molding, etc. are employ | adopted.

  Examples of the material of the release layer 613 of the fixing roll 61 include fluoro rubber, silicone rubber, and fluoro resin. Of these materials, a fluororesin is preferable. The fluororesin is not particularly limited, and examples thereof include tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-perfluoromethyl vinyl ether copolymer (MFA), and tetrafluoroethylene-perfluoroethyl vinyl ether. Copolymer (EFA), polytetrafluoroethylene (PTFE), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), polyethylene / tetrafluoroethylene (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoride ethylene (PCTFE), vinyl fluoride (PVF) and the like. These may be used alone or in combination of two or more. For the purpose of imparting antistatic properties, the release layer 613 may contain, for example, conductive powder such as carbon black, graphite, and metal powder, and for the purpose of improving wear resistance. For example, powders of inorganic compounds such as titanium oxide, iron oxide, and aluminum oxide may be blended.

  The thickness of the release layer 613 is not particularly limited, but is, for example, in the range of 10 μm to 50 μm, and preferably in the range of 15 μm to 30 μm. There is no restriction | limiting in particular as a method of forming the mold release layer 613, For example, the method etc. which coat | cover the tube formed by the coating method mentioned above and extrusion molding, etc. are mentioned.

  The pressure belt 62 has a base material 621 and a coating layer coated on the outer peripheral surface or both the outer peripheral surface and the inner peripheral surface of the base material 621, and the outermost layer of the coating layer is a fluororesin tube 622. If it is.

  The material of the base material 621 of the pressure belt 62 is, for example, one or a mixture or stainless steel selected from thermosetting polyimide resin, thermoplastic polyimide resin, polyamide resin, polyamideimide resin, polybenzimidazole resin, and the like. And metals such as nickel and copper.

  The material of the fluororesin tube 622 is not particularly limited. For example, polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoromethyl vinyl ether copolymer (MFA), tetrafluoroethylene-perfluoroethyl vinyl ether copolymer (EFA), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) such as tetrafluoroethylene-perfluoropropyl vinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer (FEP), ethylene-tetrafluoro Examples include ethylene copolymer (ETFE), polyvinylidene fluoride (PVDF), polychloroethylene trifluoride (PCTFE), and polyvinyl fluoride (PVF). Among these, polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoromethyl vinyl ether copolymer (MFA), and tetrafluoroethylene-perfluoroethyl vinyl ether copolymer are particularly preferred from the standpoints of heat resistance and mechanical properties. A tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) such as a combination (EFA) is preferred. These may be used alone or in combination of two or more. The thickness of the fluororesin tube 622 is set, for example, in the range of about 10 μm to 50 μm, preferably about 15 μm to 30 μm.

  In the fluororesin tube 622, it is preferable that both end portions of the fluororesin tube 622 are folded back to the inner peripheral surface side of the base material 621 from the viewpoint of suppressing leakage of the lubricant from the end portion of the pressure belt 62. However, since the lubricant may leak from one end of the pressure belt 62 depending on the installation direction of the fixing device 60, at least one end of the both ends of the fluororesin tube 622 is the base material. What is necessary is just to be turned back to the inner peripheral surface side of 621. Further, the end of the folded portion 623 of the fluororesin tube 622 is not particularly limited as long as it is positioned on the outer side in the axial direction from the pressure pad 64. However, from the point of suppressing the leakage of the lubricant, the pressure pad It is preferable to be positioned on the outer side in the axial direction from 64 and on the inner side in the axial direction from the meandering prevention member 70.

  The coating layer coated on the base material 621 only needs to be configured such that the outermost layer is the fluororesin tube 622. For example, an elastic body disposed between the base material 621 and the fluororesin tube 622 An intermediate layer such as a layer may be included. An example is described below.

  FIG. 6 is a schematic cross-sectional view showing another example of the configuration of the pressure belt as viewed from the direction in which the recording medium is conveyed. In the pressure belt 62 shown in FIG. 6, the coating layer coated on the base material 621 includes an elastic body layer 627 and a fluororesin tube 622 disposed on the elastic body layer 627. As described above, both end portions of the fluororesin tube 622 are folded back to the inner peripheral surface side of the base material 621, and the end of the folded portion 623 is located on the outer side in the axial direction from the pressure pad 64. Examples of the material of the elastic body layer 627 include elastic bodies such as rubber and elastomer whose rubber hardness is about 15 ° to 45 ° in terms of JIS-A hardness, and more specifically, silicone rubber, fluorine rubber, and the like. Is mentioned. Of these, silicone rubber is preferred from the viewpoints of low surface tension and excellent elasticity. Examples of such silicone rubber include RTV (room temperature vulcanization) silicone rubber, HTV (high temperature vulcanization) silicone rubber, and the like. Specifically, dimethyl silicone rubber (MQ) ), Methyl vinyl silicone rubber (VMQ), methyl phenyl silicone rubber (PMQ), fluorosilicone rubber (FVMQ), and the like. These may be used alone or in combination of two or more. The thickness of the elastic body layer 627 is, for example, 3 mm or less, and preferably in the range of 0.5 mm or more and 1.5 mm or less. There is no restriction | limiting in particular as a method of forming the elastic body layer 627 in the surface of the base material 621, For example, a well-known coating method, a shaping | molding, etc. are employ | adopted.

  The thickness of the pressure belt 62 is set to, for example, 45 μm to 130 μm, preferably 55 μm to 100 μm. When the thickness of the pressure belt 62 is less than 45 μm, the strength of the pressure belt 62 may be reduced as compared with the case where the thickness is 45 μm or more. When the thickness of the pressure belt 62 exceeds 130 μm, the heat capacity of the pressure belt 62 increases as compared with the case where the pressure belt 62 is 130 μm or less. As a result, the power consumption for securing the supply heat amount necessary for fixing increases. There is a case. The “thickness” of the pressure belt 62 means an average thickness in the width direction. The circumferential length and width of the pressure belt 62 are not particularly limited.

  Next, an example of a method for manufacturing the pressure belt 62 will be described. First, a cylindrical base material is inserted into the fluororesin tube. The length of the fluororesin tube in the axial direction (the width of the fluororesin tube) is such that both ends of the fluororesin tube protrude outward from the base material in the axial direction. Next, at both ends in the axial direction of the fluororesin tube, the portion protruding from the base material is folded back to the inner peripheral surface side of the base material to form a folded portion as shown in FIG. And the pressurizing belt 62 is obtained by heating a base material with a heater and fusing a fluororesin tube to a base material. Adhesion between the base material and the fluororesin tube is not limited to heat fusion, and the base material and the fluororesin tube may be adhered by an adhesive previously applied on the base material. In addition, the fluororesin tube and the base material are merely in contact with each other and may not be bonded. Further, for example, by removing the end of the folded portion of the fluororesin tube from the base material, a gap as shown in FIG. 5A is formed between the end of the folded portion and the inner peripheral surface of the base material. The Moreover, the protrusion part as shown to FIG.5 (b) or (c) is formed by peeling the terminal end of the folding | returning part of a fluororesin tube from a base material, and standing or bending.

  The pressure pad 64 is supported on the holder 65 by a spring, an elastic body, or the like so as to press the fixing roll 61 with a load of, for example, 30 kgf. Examples of the material of the pressure pad 64 include PPS, polyimide, polyamide, glass fiber-containing liquid crystal polymer, polyester and other resins, iron, aluminum, SUS and other metals, and metal oxides.

  For example, the pressure pad 64 may have a configuration in which an elastic body layer formed of a resin elastic body and a sheet-like member are stacked on a support. The sheet-like member may be composed of a single layer or may be composed of a plurality of layers. The sheet-like member includes a porous resin layer that holds a lubricant, which is disposed on the side in contact with the pressure belt 62, and a lubricant permeation prevention layer, which is disposed on the support side and suppresses depletion of the lubricant. It is preferable to have. Examples of the material of the porous resin layer that holds the lubricant include polyethylene resin and fluororesin. From the viewpoint of heat resistance, releasability, durability, friction resistance, etc., porous PTFE ( Polytetrafluoroethylene), PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), FEP (tetrafluoroethylene-hexafluoropropylene copolymer) and the like are preferable. These may be used alone or in combination of two or more. The material for the lubricant permeation preventive layer is selected from, for example, a heat resistant resin film or a metal film that has heat resistance and does not allow lubricant to permeate. Examples of the material of the elastic layer include elastic bodies such as rubber and elastomer whose rubber hardness is about 15 ° to 45 ° in terms of JIS-A hardness, and more specifically, silicone rubber and fluororubber. Etc. are used. The support is formed of, for example, a resin such as PPS, polyimide, polyamide, a glass fiber-containing liquid crystal polymer or polyester; a metal such as iron, aluminum, or SUS; a metal oxide.

  For example, the pressure belt 62 is preferably covered with the fixing roll 61 by a pressure pad 64 at a winding angle of about 10 °, and a nip portion N having a width of about 8 mm is formed.

  The lubricant is preferably one that maintains the lubricity with the inner peripheral surface of the pressure belt 62 even when used for a long time under a fixing temperature environment, and further, durability against long-term use under a fixing temperature environment, What is excellent in heat resistance and volatility is more preferable. An index of lubricity is kinematic viscosity. For example, a lubricant having a kinematic viscosity of 100 cSt or more and 300 cSt or less is preferable from the viewpoint of sliding resistance. The kinematic viscosity of the lubricant is measured by a capillary viscometer method (ISO 3104).

  As the lubricant, for example, liquid oil such as silicone oil and fluorine oil, synthetic lubricating oil grease in which a solid substance and a liquid are mixed, and combinations thereof are used. Examples of the silicone oil include dimethyl silicone oil, dimethyl silicone oil with an organic metal salt added, hindered amine added dimethyl silicone oil, an organic metal salt and a hindered amine added dimethyl silicone oil, methyl phenyl silicone oil, amino-modified silicone oil, and organic metal salt added amino. Examples include modified silicone oil, hindered amine-added amino-modified silicone oil, carboxy-modified silicone oil, silanol-modified silicone oil, and sulfonic acid-modified silicone oil. Examples of the fluorine oil include perfluoropolyether oil and modified perfluoropolyether oil.

  As the lubricant, silicone oil is preferable from the viewpoint of maintenance of lubricity, heat resistance, volatility, and the like. Furthermore, amino-modified silicone oil is more preferable from the viewpoint of wettability, and methylphenyl silicone oil is more preferable when heat resistance is required. From the viewpoint of improving heat resistance, an antioxidant may be added to the lubricant in the silicone oil.

  A sliding member is preferably disposed between the pressure belt 62 and the pressure pad 64. By arranging the sliding member, the sliding resistance between the pressure belt 62 and the pressure pad 64 is reduced as compared with the case where the sliding member is not arranged. The material of the sliding member is preferably, for example, a material having a small friction coefficient and excellent wear resistance and heat resistance. Specifically, sintered (sintered) PTFE resin sheets, glass fiber sheets impregnated with modified polytetrafluoroethylene, laminated sheets obtained by heat-sealing glass fibers made of fluororesin, and the like Can be mentioned.

  In the fixing device 60 illustrated in FIG. 2, the heating roller is illustrated as the rotating member, and the pressure belt disposed on the side not in contact with the toner image on the recording medium is illustrated as the belt member. The belt member is not limited to these, and the rotation member may be a pressure roll, and the belt member may be used as a fixing belt disposed on the side in contact with the toner image on the recording medium.

  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.

<Production of belt member>
Example 1
A cylindrical substrate made of polyimide having an inner diameter of 30 mm, a width of 246 mm, and a thickness of 70 μm is inserted into a fluororesin tube having an inner diameter of 30.1 mm, a width of 270 mm, and a thickness of 30 μm. Both ends of the protruding fluororesin tube were folded back to the inner peripheral surface side of the substrate to form a folded portion. Then, the base material was heated and the fluororesin tube was fused on the base material. The interval between one end and the other end of the folded portion is 220 mm, and the pressure pad is arranged at this interval.

(Example 2)
After producing the belt member in the same manner as in Example 1, the end of the folded portion of the fluororesin tube is peeled off from the substrate, and the gap between the end of the folded portion and the inner peripheral surface of the substrate is shown in FIG. A gap as shown was formed.

(Example 3)
After producing a belt member in the same manner as in Example 1, the end of the folded portion of the fluororesin tube was peeled off from the base material to stand up, and a protruding portion as shown in FIG. 5B was formed.

Example 4
After producing the belt member in the same manner as in Example 1, the end of the folded portion of the fluororesin tube was peeled off from the substrate and bent to form a protruding portion as shown in FIG.

(Comparative Example 1)
After inserting a cylindrical substrate made of polyimide having an inner diameter of 30 mm, a width of 246 mm, and a thickness of 70 μm into a fluororesin tube having an inner diameter of 30.1 mm, a width of 246 mm, and a thickness of 30 μm, the substrate is heated, A fluororesin tube was fused onto the substrate. In Comparative Example 1, the fluororesin tube and the base material have the same width (length in the axial direction), and both end portions of the fluororesin tube are not folded back to the inner peripheral surface side of the base material.

(Comparative Example 2)
After producing a belt member in the same manner as in Comparative Example 1, tubular bodies of PPS (material) were disposed at both ends on the inner peripheral surface side of the base material. This tubular body is disposed on the outer side in the axial direction of the belt member from the pressure pad, and is in contact with the outer peripheral surface of the insertion portion of the belt meandering prevention member.

<Test with fixing device>
The belt member obtained in Example 1 was attached as a pressure belt to the fixing device shown in FIG. In this fixing device, an idling test for 100 hours was performed at a surface speed of the fixing roll of 160 mm / sec while maintaining the surface temperature of the pressure belt at 180 ° C. The rotational torque of the fixing roll under test was measured using a rotational torque meter (TP-5KCE, manufactured by Kyowa Denki Co., Ltd.). Further, the presence or absence of leakage of the lubricant from both ends of the pressure belt and contact between the pressure belt and other members was visually observed. As a result, the rotational torque immediately after the start of the test was 0.165 N · m, and the rotational torque of the fixing roll after 100 hours was 0.171 N · m. That is, the rotational torque of the fixing roll after 100 hours had increased only by about 0.006 N · m with respect to immediately after the start of the test. In addition, even after 100 hours had elapsed, no lubricant leaked from both ends of the pressure belt, and further, no rotation failure of the pressure belt occurred.

  In Examples 2-4 and Comparative Examples 1-2, the same test as in Example 1 was performed. As a result, in all of Examples 2 to 4, the fixing roll rotational torque after 100 hours had increased only by about 0.004 N · m with respect to immediately after the start of the test. In all of Examples 2 to 4, leakage of the lubricant from both ends of the pressure belt did not occur, and rotation failure of the pressure belt did not occur.

  In Comparative Example 1, leakage of the lubricant occurred from both ends of the pressure belt within a few hours from the start of the test, and the rotational torque of the fixing roll increased by 0.21 N · m compared to immediately after the start of the test. In Comparative Example 2, the lubricant leaked from both ends of the pressure belt in 30 hours from the start of the test, and the rotational torque of the fixing roll increased by 0.19 N · m compared to immediately after the start of the test. The increase in the rotational torque of the fixing roll is considered to be due to the fact that the lubricant leaks from both ends of the pressure belt, and the frictional resistance between the pressing member and the inner peripheral surface of the pressure belt increases.

  1Y, 1M, 1C, 1K Image forming unit, 10 Primary transfer unit, 11 Photosensitive drum, 12 Charger, 13 Laser exposure unit, 14 Developer, 15 Intermediate transfer belt, 16 Primary transfer roll, 17 Drum cleaner, 20 2 Next transfer section, 22 Secondary transfer roll, 25 Backup roll, 26 Feed roll, 31 Drive roll, 32 Support roll, 33 Tension roll, 34 Cleaning backup roll, 35 Intermediate transfer belt cleaner, 40 Control section, 42 Reference sensor, 43 Image density sensor, 50 paper tray, 51 pickup roll, 52 transport roll, 53 transport chute, 55 transport belt, 56 fixing inlet guide, 60 fixing device, 61 fixing roll, 62 pressure belt, 63 belt travel guide, 64 pressure pad 65 holders, 66 Halogen heater, 67 Lubricant application member, 69 Temperature sensor, 70 Meandering prevention member, 72 Flange part, 74 Insertion part, 100 Image forming apparatus, 611 Core, 612 Elastic body layer, 613 Release layer, 621 Base material, 622 Fluororesin tube, 623 folded portion, 624 gap portion, 625 projecting portion, 627 elastic layer.

Claims (5)

A cylindrical base material, and a coating layer disposed on the outer peripheral surface of the base material,
The coating layer has a fluororesin tube that is the outermost layer of the coating layer,
The end portion of the fluororesin tube is folded back to the inner peripheral surface side of the base material, and the end of the folded portion is positioned on the outer side in the axial direction from the pressing member disposed on the inner peripheral surface side of the base material. A belt member.   The belt member according to claim 1, wherein a gap is formed between an end of the folded portion and an inner peripheral surface of the base material.   The belt member according to claim 1, wherein a terminal end of the folded portion protrudes radially inward of the base material.   A rotatable rotating member, a belt member according to any one of claims 1 to 3 that is movable while being in contact with the rotating member, and disposed so as to face the rotating member via the belt member. And a pressing member that presses the belt member toward the rotating member to form a nip portion through which a recording medium passes between the rotating member and the belt member. . An image carrier, a charging unit for charging the surface of the image carrier, a latent image forming unit for forming an electrostatic latent image on the charged surface of the image carrier, and the electrostatic latent image by a developer. A developing unit that develops a toner image, a transfer unit that transfers the toner image onto a recording medium, and a fixing device according to claim 4 that fixes the toner image onto the recording medium. Image forming apparatus.

Images