Fixing member and heat fixing device

Abstract

To provide a fixing film including a mold release layer that can improve split (crack) resistance while maintaining wear resistance with a sheet, thereby stably exhibiting good fixing performance, and a heat fixing device.SOLUTION: A fixing film has a cylindrical substrate, an elastic layer provided on an outer peripheral surface of the cylindrical substrate, and a mold release layer provided on an outer peripheral surface of the elastic layer. The degree of orientation of the mold release layer measured by the X-ray diffraction method is 40% or more and 59% or less, and the thermal diffusivity in a film thickness direction at 170°C of the mold release layer is 5.9×10-8 m2 / s or more.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a fixing member used in a heat fixing device of an electrophotographic image forming apparatus. [Background technology]

[0002] An electrophotographic image forming apparatus is equipped with a fixing device that fixes a toner image formed on a recording material (hereinafter referred to as paper) to the paper by applying heat and pressure to the toner image. This fixing device is equipped with fixing members such as a heating roller (heating film) and a pressure roller (pressure film), and the fixing process is performed at a position where these are pressed against each other (fixing nip portion).

[0003] One example of a fixing device is a film heating type device. This device has a heater as a heating element (heat source) having a resistance heating element on a ceramic substrate. It has an endless fixing film as a heating element that rotates while containing and contacting the heater. It also has a pressure roller (pressure rotating body) as a nip portion forming member that presses against the fixing film to form a nip portion and rotates the fixing film. This film heating type allows for the fixing film to have a low thermal capacity and be made smaller, which makes it possible to save energy in the fixing device and shortens the time (warm-up time) required for the temperature of the fixing film to reach a predetermined temperature sufficient to heat and fix a toner image.

[0004] The film substrate is made of a heat-resistant resin material such as polyimide, or a metal material such as nickel electroplating or stainless steel. An elastic layer made of heat-resistant rubber such as silicone rubber is then applied to the film substrate. The elastic layer allows the surface of the fixing member to deform in line with the toner image on the paper as the paper passes through the nip, increasing the contact area and reducing contact thermal resistance. This allows the toner to be uniformly melted and fixed onto the paper, resulting in a high-quality image with a high gloss and no uneven fixation.

[0005] Such fixing members have a release layer on their surface to provide release properties for toner. Fluorocarbon resins such as polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), and tetrafluoroethylene-hexafluoropropylene copolymer (FEP) are commonly used as materials for the release layer. The release layer in fixing films with the release layer on the surface of the elastic layer described above can be formed by coating the surface of the elastic layer with a dispersion (water-based dispersion paint) or powder paint primarily composed of the fluorocarbon resin described above and heating it above its melting point to form a film, or by covering the surface of the elastic layer with a fluorocarbon resin (mainly PFA) tube manufactured by extrusion molding separately.

[0006] However, the fluororesin essential for ensuring release properties has low thermal conductivity, resulting in reduced heating efficiency and reduced energy savings. Furthermore, the fluororesin is harder than the elastic layer, impairing flexibility—a necessary characteristic for reducing thermal contact resistance with the paper—leading to poor image quality, such as uneven fusing. Therefore, to minimize energy savings and image quality, it is desirable to form the release layer as thin as possible. However, making it too thin reduces the durability of the release layer, which is the time it takes for the layer to break down due to wear caused by friction with the paper. Furthermore, extruded tubes are prone to cracking in the direction of orientation (extrusion direction) due to molecular orientation during extrusion. This is caused by differences in the expansion coefficient between the elastic layer and the rubber at the fusing temperature range and repeated bending stress near the nip as the film is rotated. Cracks in the release layer are transferred to the toner image after fusing, resulting in poor image quality.

[0007] Patent Document 1 discloses a method for reducing orientation by reheating the fixing film after covering it with a PFA tube to above its melting point and then rapidly cooling it. In this method, molecular motion occurs as the PFA is remelted, and the orientation history during tube extrusion can be eliminated. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-197507 Summary of the Invention [Problem to be solved by the invention]

[0009] However, if the orientation of the PFA is significantly reduced by remelting, the abrasion resistance to paper that was maintained by the orientation is also significantly reduced. As a result, although the resistance to cracking is improved, there is the problem that it is not possible to achieve both the abrasion resistance (durability) against friction with paper mentioned above.

[0010] Therefore, an object of the present invention is to provide a fixing film and a heat fixing device equipped with a release layer that maintains abrasion resistance with paper, improves crack resistance, and can stably exhibit good fixing performance. [Means for solving the problem]

[0011] In order to achieve the above object, the fixing film according to the present invention has a cylindrical substrate, an elastic layer provided on the outer peripheral surface of the cylindrical substrate, and a release layer provided on the outer peripheral surface of the elastic layer, wherein the release layer has a degree of orientation of 40% or more and 59% or less by X-ray diffraction method and a thermal diffusivity in the film thickness direction at 170°C of 5.9 × 10 -8 m 2 / s or more. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a fixing film and a heat fixing device that are provided with a release layer that has resistance to abrasion and cracking with paper and can stably exhibit good fixing performance. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic diagram illustrating an example of an electrophotographic image forming apparatus. [Figure 2] 1 is a schematic cross-sectional view illustrating a configuration of a fixing device according to an embodiment. [Figure 3] FIG. 2 is a diagram illustrating a configuration of a fixing film. [Figure 4] 10A and 10B are diagrams showing an example of the results of measuring the degree of orientation of a release layer in an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0015] [Image forming device] Figure 1 is a schematic diagram of an example of an image forming apparatus. This image forming apparatus is an electrophotographic image forming apparatus and has a rotating electrophotographic photosensitive member 101. It has a charging device 102 and an image exposure device 103 as electrostatic latent image forming devices for the photosensitive member 101, and a developing device 104 that develops the electrostatic latent image on the photosensitive member 101 into a toner image (developer image). It also has a transfer device 105 that transfers the toner image on the photosensitive member 101 to a sheet-like recording material (hereinafter referred to as paper or paper) P. It also has a cleaning device 106 that cleans the surface of the photosensitive member 101 after the toner image has been transferred, and a fixing device 10 (Figure 2) that serves as a fixing device that fixes the toner image T on the paper P.

[0016] [Fixing device] FIG. 2 is a cross-sectional view showing the general configuration of a fixing device 10 according to this embodiment. In the following description, with respect to the fixing device and the components constituting this fixing device, the axial direction refers to the direction perpendicular to the paper conveyance direction on the surface of the paper. The length refers to the dimension in the axial direction. This fixing device 10 is a belt (film) heating type fixing device. It includes a ceramic heater (hereinafter referred to as heater) 1 as a heating element and a film guide 2 that also serves as a heating element support member. It also includes an endless (cylindrical), flexible, and heat-resistant fixing film 20 as a heating member (fixing member). It also includes a pressure roller 30 as a nip portion forming member that presses against the fixing film 20 to form a nip portion (fixing nip portion) N.

[0017] The heater 1 is a long, thin plate-like member extending along the longitudinal direction of the fixing film 20 (perpendicular to the drawing), and has a heat source such as a resistance heating element that generates heat when energized by a power supply means (not shown), and its temperature rises sharply when power is supplied. The temperature of the heater 1 is detected by a temperature detection means (not shown), and the detected temperature information is input to a control means (not shown). The control means controls the power supplied from the power supply means to the heat source so that the detected temperature input from the temperature detection means is maintained at a predetermined fixing temperature, thereby regulating the temperature of the heater 1 to a predetermined temperature.

[0018] Heater 1 is supported by film guide 2, which is made of a rigid, heat-resistant material and has a trough-like shape with a roughly semicircular cross section. More specifically, a groove 2a is provided on the outer surface of film guide 2 along the guide length, and heater 1 is fitted into this groove 2a.

[0019] As will be described later, the fixing film 20 includes, from the inside to the outside, an annular (cylindrical) base material 21, an elastic layer 22, a release layer 24, etc. (FIG. 3). The fixing film 20 is an endless film whose inner circumferential surface is rubbed against the heater 1 and the film guide 2 when in use, and is fitted onto the outer periphery of the film guide 2 that supports the heater 1 with some leeway in its circumferential length.

[0020] The heater 1 and the pressure roller 30 are in pressure contact with each other, sandwiching the fixing film 20 therebetween, and a nip N is formed between the fixing film 20 and the pressure roller 30. The pressure roller 30 is driven to rotate at a predetermined peripheral speed in the counterclockwise direction of arrow R30 by a rotation drive device M such as a motor. Driven by the rotation of the pressure roller 30, the fixing film 20 rotates in the clockwise direction of arrow R20 around the outside of the film guide 2, with its inner surface sliding in close contact with the surface of the heater 1. Both longitudinal ends of the fixing film 20 are rotatably supported by flanges (not shown) that are regulating members fixed to the fixing device 10.

[0021] The film guide 2 functions as a support member for the heater 1 and also as a rotation guide member for the fixing film 20. A lubricant (grease) is applied to the inner surface of the fixing film 20 to ensure sliding between the heater 1 and the film guide 2.

[0022] The pressure roller 30 comprises, from the inside to the outside, a base body 31 in the shape of a solid round bar or a cylinder (pipe), an elastic layer 32, and a release layer 33. The pressure roller 30 is driven to rotate by a rotation drive device M such as a motor during use. Therefore, both axial ends of the base body 31 are rotatably supported via bearing members on fixed parts (not shown) such as the frame of the fixing device 10.

[0023] The pressure roller 30 is disposed opposite the heater 1 supported by the film guide 2, sandwiching the fixing film 20 therebetween. A pressure mechanism (not shown) applies a predetermined pressure to the pressure roller 30 and the fixing film 20, bringing them into pressure contact with each other and elastically deforming their respective elastic layers (22, 32). As a result, a nip N of a predetermined width in the paper transport direction is formed between the pressure roller 30 and the fixing film 20.

[0024] The pressure contact between the fixing film 20 as a heating member and the pressure roller 30 as a nip forming member may be a configuration in which the pressure roller 30 is pressed against the fixing film 20 at a predetermined pressure, or a configuration in which the fixing film 20 side is pressed against the pressure roller 30. Also, a configuration in which both the fixing film 20 side and the pressure roller 30 are pressed against each other at a predetermined pressure may be used.

[0025] When pressure roller 30 is driven to rotate by rotation drive device M, it conveys paper P while nipping it at nip N between it and fixing film 20, which is driven to rotate. Furthermore, heater 1 heats fixing film 20 until its surface reaches a predetermined temperature (e.g., 200°C). In this state, paper P carrying an unfixed toner image T is introduced into nip N and conveyed while being nipped, whereby unfixed toner T on paper P is heated and pressurized. As a result, unfixed toner T melts and mixes colors, and then cools, and the toner image is fixed to paper P as a fixed image.

[0026] [Fixing film] Next, the fixing film 20 in this embodiment will be described in detail.

[0027] 3A and 3B are cross-sectional schematic diagrams showing the layer structure of the fixing film 20, which is the fixing member in the conventional example (a) and the present example (b). 21 is the substrate (cylindrical substrate) of the fixing film 20, 25 is an inner sliding member disposed on the inner peripheral surface of the substrate 21, 26 is a primer layer covering the outer peripheral surface of the substrate 21, and 22 is an elastic layer disposed on the primer layer 26. 24 is a fluororesin tube serving as a release layer, and 23 is an adhesive layer for fixing the release layer 24 on the elastic layer 22.

[0028] Each of the constituent layers will be specifically described below.

[0029] (3-1) Base material 21 Considering the need for heat resistance and flexibility, the substrate 21 of the fixing film 20 is preferably made of a heat-resistant resin such as polyimide, polyamideimide, or polyetheretherketone (PEEK), or, taking thermal conductivity into consideration, a metal such as stainless steel (SUS), nickel, or a nickel alloy, which has a higher thermal conductivity than heat-resistant resin. Since the substrate 21 needs to have a low heat capacity while maintaining high mechanical strength, it is desirable for the thickness to be 5 to 100 μm, preferably 20 to 85 μm. In this embodiment, a SUS substrate with an inner diameter of 24 mm and a thickness of 30 μm is used.

[0030] (3-2) Inner sliding layer 25 A resin with both high durability and high heat resistance, such as polyimide resin, is suitable for the inner sliding layer 25. In this embodiment, a polyimide precursor solution obtained by reacting an aromatic tetracarboxylic dianhydride or its derivative with an aromatic diamine in a substantially equimolar organic polar solvent is applied to the inner circumferential surface of the substrate 21. After the solvent is dried, the inner sliding layer 25 is formed by heating to induce a dehydration ring-closing reaction (imidization reaction). Because the inner sliding layer 25 gradually wears due to friction with the heater 1, it must have a thickness sufficient to function as a sliding layer throughout its lifespan. On the other hand, if the thickness is too large, it will function as a thermal resistance layer that impedes the heat supply from the heater 1. Therefore, the thickness is preferably 5 to 20 μm, and more preferably 10 to 15 μm. In this embodiment, the thickness of the inner sliding layer 25 was 12 μm.

[0031] (3-3) Elastic layer 22 An elastic layer 22 is provided on the outer peripheral surface of the substrate 21 via a primer layer 26. When the paper P passes through the nip N, the elastic layer 22 envelops the unfixed toner T on the paper P, uniformly applying heat to the unfixed toner T. This function of the elastic layer 22 results in a high-quality image with high gloss and no uneven fixing. Addition-crosslinked liquid silicone rubber is preferably used as the material for the elastic layer 22 because it is easy to process, can be processed with high dimensional accuracy, and does not produce reaction by-products during heat curing. The addition-crosslinked liquid silicone rubber contains, for example, organopolysiloxane and organohydrogenpolysiloxane, and may further contain catalysts and other additives. The organopolysiloxane is a base polymer made from silicone rubber, and it is recommended to use one with a number-average molecular weight of 5,000 to 100,000 and a weight-average molecular weight of 10,000 to 500,000.

[0032] Liquid silicone rubber is a polymer that is fluid at room temperature, but hardens when heated. After hardening, it has a moderately low hardness and sufficient heat resistance and deformation recovery. Therefore, liquid silicone rubber is suitable for use not only in the belt elastic layer 22, but also in the elastic layer 32 of the pressure roller 30, which will be described later. However, if the elastic layer 22 is formed solely from silicone rubber, the thermal conductivity of the elastic layer 22 will be low. If the thermal conductivity of the elastic layer 22 is low, it will be difficult for the heat generated by the heater 1 to be transferred to the paper P through the fixing film 20. This can result in insufficient heating when fixing toner to the paper P, resulting in image defects such as uneven fixing.

[0033] Therefore, in order to increase the thermal conductivity of the elastic layer 22, a highly thermally conductive filler, for example, granular, is mixed and dispersed in the elastic layer 22. Examples of granular highly thermally conductive fillers include silicon carbide (SiC), zinc oxide (ZnO), alumina (Al2O3), aluminum nitride (AlN), magnesium oxide (MgO), and carbon. These may be used alone or in combination of two or more. The average particle size of the highly thermally conductive filler is preferably 1 μm or more and 50 μm or less from the viewpoints of handling and dispersibility.

[0034] The shape may be spherical, pulverized, needle-like, plate-like, whisker-like, or the like, but spherical is preferred from the viewpoint of dispersibility. The thickness of the elastic layer 22 is desirably 30 to 500 μm, preferably 100 to 300 μm, to obtain high-quality images through sufficient elasticity and to prevent the time required to reach a predetermined temperature by heating from being delayed due to increased heat capacity. In this embodiment, alumina is used as the highly thermally conductive filler, and the elastic layer 22 has a thermal conductivity of 1.0 W / mK and a thickness of 250 μm.

[0035] (3-4) Adhesive layer 23 The adhesive layer 23, which fixes the fluororesin tube serving as the release layer 24 onto the cured silicone rubber serving as the elastic layer 22, is applied to the surface of the elastic layer 22 to a thickness of 1 to 10 μm (an adhesive application step in which an adhesive is applied to the outer peripheral surface of the cylindrical elastic layer). In this example, the adhesive layer 23 is made of a cured product of an addition-curing silicone rubber adhesive. The addition-curing silicone rubber adhesive 23 contains an addition-curing silicone rubber blended with a self-adhesive component. Specifically, it contains an organopolysiloxane having an unsaturated hydrocarbon group, typically a vinyl group, a hydrogenorganopolysiloxane, and a platinum compound as a crosslinking catalyst. It then hardens by addition reaction. Known adhesives can be used as such adhesives.

[0036] (3-5) Release layer 24 For the surface layer (toner release layer) of the fixing member, an extrusion-molded fluororesin tube 24 is used from the viewpoint of moldability and toner releasability. Tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), which has excellent heat resistance, is preferably used as the fluororesin (PFA tube). The copolymerization method of the raw material PFA is not particularly limited, and examples include random copolymerization, block copolymerization, and graft copolymerization. Furthermore, the molar ratio of tetrafluoroethylene (TFE) to perfluoroalkyl vinyl ether (PAVE) in the raw material PFA is not particularly limited. For example, a TFE / PAVE molar ratio of 94 / 6 to 99 / 1 can be preferably used.

[0037] Other fluororesins include tetrafluoroethylene / hexafluoropropylene copolymer (FEP), polytetrafluoroethylene (PTFE), and ethylene / tetrafluoroethylene copolymer (ETFE). Other examples include polychlorotrifluoroethylene (PCTFE), ethylene / chlorotrifluoroethylene copolymer (ECTFE), and polyvinylidene fluoride (PVDF). These fluororesins can be used alone or in combination. The thickness of the release layer 24 is preferably 10 μm or greater to maintain its function as a release layer over a long period of time, taking into account wear due to friction with the paper. On the other hand, if the thickness is too large, increased thermal resistance reduces heating efficiency, and a lack of flexibility increases contact thermal resistance with the paper, resulting in reduced energy efficiency and reduced image quality. Therefore, the thickness is preferably 30 μm or less. In this example, a PFA tube with a thickness of 15 to 25 μm obtained by extrusion molding was used.

[0038] The evaluation of the fixing film 20 constructed by laminating the above and its release layer 24 will be described below with reference to Examples 1 to 4 and Comparative Examples 1 to 4 described later.

[0039] [Degree of orientation of release layer] The degree of orientation of the release layer 24 was determined by calculation from the β rotation angle distribution of the diffraction intensity using an X-ray diffractometer (MiniFlex manufactured by Rigaku Corporation). PFA as the release layer separated from the fixing film was set on a fiber sample stage, and with 2θ fixed at a peak around 18°, the intensity distribution along the Debye ring when rotated 360° (β rotation) using the transmission method was measured, and the degree of orientation was calculated using the following formula. H = [(360-ΣW / 360)] × 100 Here, H is the degree of orientation [%], and W is the half-width.

[0040] Figure 4 shows an example of the measurement results.

[0041] [Thermal diffusivity of release layer] The thermal diffusivity of the release layer 24 in the thickness direction was measured using a cyclic heating thermal diffusivity measuring device (FTC-1 manufactured by Advance Riko Co., Ltd.) The release layers used in the present examples and comparative examples were measured at a measurement temperature of 170°C and a measurement frequency of 60 to 100 Hz.

[0042] [Evaluation of durability of fixing film] 2, which incorporates the fixing films of the examples and comparative examples. The pressure roller was rotated so that the surface movement speed (circumferential speed) of the pressure roller was 246 mm / sec, with the pressure applied to one end being approximately 156.8 N and the total pressure applied being approximately 313.6 N (32 kgf). Paper of the same size (A4 landscape) was continuously passed through the pressure roller while the surface temperature of the paper passing portion of the fixing film was controlled to 170°C.

[0043] The paper passing life was evaluated as ◯ when the paper edge was not worn off and 500,000 sheets or more could be passed through, and x when the paper edge was worn off and disappeared during the durability test.

[0044] In addition, every 100,000 sheets, coated paper OK top coat 128 g / m 2 A blue solid image was printed on a sheet of paper (SRA3 or 13 x 19 inch paper) wider than A4 landscape (manufactured by Oji Paper Co., Ltd.). If scratches or sharp streaks caused by cracks in the release layer in the axial direction of the fixing film (the PFA tube extrusion direction) were visible on this image, it was marked with an "X", and if they were not visible, it was marked with an "O".

[0045] [Evaluation of uneven toner melting] By observing the melted state of the toner after fixing the toner image formed on the paper, it is possible to obtain an index of the ability of the fixing film to follow the unevenness of the paper.

[0046] As in the durability evaluation, ten sheets of paper for evaluating uneven melting were fixed in succession using a fixing device 10 incorporating a fixing film, in an environment of a temperature of 10°C and a relative humidity of 50%, at an input voltage of 100 V. The paper used was A4-sized recycled paper (product name: Recycled Paper GF-R100; manufactured by Canon Inc., thickness 92 μm, basis weight 66 g / m). 2 The paper used was 70% recycled paper, with a Beck smoothness of 23 seconds (measured using a method conforming to JIS P8119). The image used to evaluate uneven melting was a 10mm x 10mm patch image formed with cyan toner and magenta toner at 100% concentration, placed near the center of the paper.

[0047] As a guideline for uneven melting, sufficient heat and pressure must be applied to the image area where two colors are formed, causing the toner to melt and mix. In particular, if heat is applied but no pressure is applied to the concave areas of the paper, the toner grain boundaries remain after fixing, resulting in insufficient color mixing and uneven melting. If the fixing member cannot adequately conform to the concave and convex surfaces, pressure is applied to the convex areas, causing color mixing, but insufficient color mixing in the concave areas. Therefore, conformability to the concave and convex surfaces was confirmed by observing the melting state of the image-forming area.

[0048] After printing 10 consecutive sheets of images to evaluate uneven melting, the 10th sample was taken and the image-formed area was observed under an optical microscope to evaluate uneven melting. The evaluation criteria are as follows (see "Uneven Melting" in Table 1):

[0049] Evaluation rank A: Toner grain boundaries are barely visible even in the recesses of the paper fibers, and the colors are mixed in both the recesses and protrusions. B: Although some toner grain boundaries are observed in the recesses of the paper fibers, the colors are generally mixed in both the recesses and protrusions. C: Only the convex parts of the paper fibers are mixed, and many toner grain boundaries are observed in the concave parts.

[0050] The PFA tubes used as the release layers of the fixing films of the examples and comparative examples have different degrees of orientation and thermal diffusivities after molding, which are obtained by changing the extrusion molding conditions.

[0051] [Table 1]

[0052] As shown in the above examples, if the degree of orientation of the release layer is within the range of 40 to 59%, a fixing film can be obtained that has good fixing performance without uneven toner melting, sufficient paper passing life against paper abrasion, and does not cause image defects due to cracks throughout its life.

[0053] On the other hand, in Comparative Example 1, the degree of orientation of the release layer is less than 40 (38%), so the abrasion resistance with the paper is insufficient and the desired paper feed life cannot be achieved. Furthermore, in Comparative Examples 2 to 4, the degree of orientation of the release layer is 60% or more, so the release layer develops cracks during use, resulting in visible streaks in the image. In Comparative Examples 2 and 4, in addition to the high degree of orientation, the release layer is also relatively thick, at 20 μm or more, so the flexibility of the release layer is impaired, the ability to follow the unevenness of the paper is insufficient, and uneven toner melting becomes noticeable. [Explanation of symbols]

[0054] 1 Ceramic heater 2 Film Guide 10 Fixing device 20 Fixing film 21 Base material 22 Elastic layer 23 Adhesive layer 24 Release layer 25 Inner sliding layer 26 Primer layer 30 Pressure roller 31 Base 32 Elastic layer 33 Release layer

Claims

1. at least, a cylindrical substrate; an elastic layer formed on the outer peripheral surface of the cylindrical substrate; a release layer formed on the outer peripheral surface of the elastic layer; and The release layer Made of fluororesin, The degree of orientation according to an X-ray diffraction method is 40% or more and 59% or less, The thermal diffusivity in the film thickness direction at 170°C is 5.9 × 10 －８ m ２ / s or more A fixing film characterized by:

2. The fluororesin of the release layer is made of tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin (PFA).

2. The fixing film according to claim 1, wherein the fixing film is a fixing film having a thickness of 100 nm or less.

3. The release layer is a PFA tube having a thickness of 10 μm or more and 30 μm or less.

3. The fixing film according to claim 1, wherein the fixing film is a fixing film having a thickness of 100 nm or less.

4. the fixing film is a component of a fixing device that fixes a toner image transferred onto a recording material by heating, The release layer is in contact with the toner image forming surface of the recording material when an image is formed on one side of the recording material.

2. The fixing film according to claim 1, wherein the fixing film is a fixing film having a thickness of 100 nm or less.

5. A heat fixing device comprising the fixing film according to any one of claims 1 to 4.

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