Fixing member, fixing device, and image forming apparatus

Abstract

To provide a fixing member that has fixability and separability without including a fluorine compound and a silane compound.SOLUTION: A fixing member has a surface layer including resin and not including a fluorine compound and a silane compound, and the surface layer has a hexadecane contact angle of 25° or more at 150°C.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a fixing member, a fixing device, and an image forming apparatus. [Background technology]

[0002] Conventionally, electrophotographic image forming apparatuses, including copiers and laser beam printers, have a fixing device that brings a heated fixing member into contact with an unfixed toner image carried on a recording medium to fix the toner image to the recording medium (see, for example, Patent Document 1). Such fixing devices are configured to thermocompress the toner image onto the conveyed recording medium and to allow the recording medium to peel off from the fixing member. In addition, the fixing member is required to have a surface that is not soiled by toner or wax, and to be made of a material with a high melting point so that the toner can be melted on the surface of the fixing member.

[0003] Patent Document 1 describes a fixing device having a pressure member, a pressure roller, a fixing belt, and a conveying roll. The fixing belt in the fixing device described in Patent Document 1 has a heat-resistant sheet, an elastic layer disposed on the heat-resistant sheet, and an outermost layer containing fluororesin disposed on the elastic layer. In the fixing device described in Patent Document 1, the fixing belt exhibits the above-mentioned functions by having the outermost layer containing fluororesin. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-321908 Summary of the Invention [Problem to be solved by the invention]

[0005] Here, fluororesins are very chemically stable, so they remain semi-permanently even after the end of the product life of the product in which they are used. Furthermore, some fluororesins are feared to have adverse effects on the human body due to their bioaccumulation and toxicity. In Europe and other countries, restrictions on PFAS (Per and Polyfluoroalkyl Substances), a general term for organic fluororesins, are being implemented, and it is expected that restrictions on the use of organic fluororesins will become even stricter in the future. Therefore, it is desirable to use fixing members made of resins other than fluororesins, even in image forming apparatuses that have the fixing device described in Patent Document 1.

[0006] Therefore, an object of the present invention is to provide a fixing member that has fixability and separability without containing a fluorine compound or a silane compound, and another object of the present invention is to provide a fixing device and an image forming apparatus that include the fixing member. [Means for solving the problem]

[0007] A fixing member according to one embodiment of the present invention has a surface layer that contains a resin but does not contain a fluorine compound or a silane compound, and the surface layer has a hexadecane contact angle of 25° or more at 150°C.

[0008] A fixing device according to one embodiment of the present invention includes the fixing member of the present invention, a plurality of rollers that axially support the fixing member, and a heating section that heats the fixing member.

[0009] An image forming apparatus according to one embodiment of the present invention has the fixing device of the present invention, which fixes an unfixed toner image formed on a recording medium by an electrophotographic method to the recording medium by applying heat and pressure. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a fixing belt having high separability and fixing ability, and a fixing device and an image forming apparatus that include this fixing belt. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram showing a configuration of an image forming apparatus according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing a configuration of the fixing device according to the first exemplary embodiment of the present invention. [Figure 3] 3A and 3B are diagrams showing the configuration of a fixing belt according to the first embodiment of the present invention. [Figure 4] FIG. 4 is a diagram showing a configuration of a fixing device according to the second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0013] [Embodiment 1] (Configuration of image forming apparatus and fixing device) Fig. 1 is a diagram showing the configuration of an image forming apparatus 10 according to the first embodiment of the present invention, and Fig. 2 is a diagram showing the configuration of a fixing device 60 according to the first embodiment of the present invention.

[0014] As shown in FIG. 1, the image forming apparatus 10 includes an image reading unit 20, an image forming unit 30, an intermediate transfer unit 40, a fixing device 60, and a recording medium conveying unit 80.

[0015] The image reading unit 20 reads an image from the document D and obtains image data for forming an electrostatic latent image. The image reading unit 20 includes a paper feeder 21, a scanner 22, a CCD sensor 23, and an image processing unit 24.

[0016] The image forming section 30 includes, for example, four image forming units 31 corresponding to the colors yellow, magenta, cyan, and black. Each image forming unit 31 has a photosensitive drum 32, a charging device 33, an exposure device 34, a developing device 35, and a cleaning device 36.

[0017] The photosensitive drum 32 is, for example, a negatively charged organic photosensitive material having photoconductivity. The charging device 33 charges the photosensitive drum 32. The charging device 33 is, for example, a corona charger. The charging device 33 may also be a contact charging device that charges the photosensitive drum 32 by contacting a contact charging member such as a charging roller, charging brush, or charging blade with the photosensitive drum 32. The exposure device 34 irradiates the charged photosensitive drum 32 with light to form an electrostatic latent image. The exposure device 34 is, for example, a semiconductor laser. The developing device 35 supplies toner to the photosensitive drum 32 on which the electrostatic latent image has been formed, forming a toner image corresponding to the electrostatic latent image. The developing device 35 is, for example, a known developing device used in electrophotographic image forming apparatuses. The cleaning device 36 removes residual toner from the photosensitive drum 32. Here, the term "toner image" refers to a state in which toner is collected in an image-like form.

[0018] Known toners can be used. The toner may be a one-component developer or a two-component developer. A one-component developer is composed of toner particles. A two-component developer is composed of toner particles and carrier particles. The toner particles are composed of toner base particles and an external additive such as silica attached to the surface thereof. The toner base particles are composed of, for example, a binder resin, a colorant, and a wax.

[0019] The intermediate transfer section 40 includes a primary transfer unit 41 and a secondary transfer unit 42 .

[0020] The primary transfer unit 41 includes an intermediate transfer belt 43, a primary transfer roller 44, a backup roller 45, a plurality of first support rollers 46, and a cleaning device 47. The intermediate transfer belt 43 is an endless belt. The intermediate transfer belt 43 is stretched by the backup roller 45 and the first support roller 46. The intermediate transfer belt 43 runs in one direction at a constant speed on an endless track as at least one of the backup roller 45 and the first support roller 46 is driven to rotate.

[0021] The secondary transfer unit 42 includes a secondary transfer belt 48, a secondary transfer roller 49, and a plurality of second support rollers 50. The secondary transfer belt 48 is an endless belt. The secondary transfer belt 48 is stretched between the secondary transfer roller 49 and the second support rollers 50.

[0022] 2, the fixing device 60 fixes an unfixed toner image formed on the recording medium S by electrophotography to the recording medium S by applying heat and pressure. The fixing device 60 has a fixing member 61, a heating roller 62, a first pressure roller 63, a second pressure roller 64, heaters (heating units) 65 and 66, a first temperature sensor 67, a second temperature sensor 68, an airflow separating device 69, a guide plate 70, and a guide roller 71.

[0023] The shape of the fixing member 61 is not particularly limited as long as the fixing device 60 can perform the above-described functions. The shape of the fixing member 61 includes an endless belt shape, a roller shape, and a plate shape. In this embodiment, the fixing member 61 is an endless belt shape. The fixing member 61 is composed of a base layer 61a, an elastic layer 61b, and a surface layer 61c laminated in this order (see FIG. 3). The fixing member 61 is axially supported by two or more rollers with the base layer 61a facing inward and the surface layer 61c facing outward. In this embodiment, the fixing member 61 is axially supported by the heating roller 62 and the first pressure roller 63. The tension of the fixing member 61 is preferably 45 N or less. If the tension of the fixing member 61 exceeds 45 N, the first pressure roller 63 may be damaged. The tension of the fixing member 61 is, for example, 43 N.

[0024] Heating roller 62 has a rotatable aluminum sleeve and heater 65 disposed therein. The type of heater 65 is not particularly limited. Examples of types of heater 65 include a halogen heater (halogen heater type) and an electromagnetic induction coil (IH type). In this embodiment, heater 65 is a halogen heater disposed inside heating roller 62. First pressure roller 63 has, for example, a rotatable core metal and an elastic layer disposed on the outer circumferential surface thereof.

[0025] The second pressure roller 64 is disposed opposite the first pressure roller 63 across the fixing belt 61. The second pressure roller 64 includes, for example, a rotatable aluminum sleeve and a heater 66 disposed within the sleeve. The second pressure roller 64 is disposed so as to be able to approach and move away from the first pressure roller 63. When the second pressure roller 64 approaches the first pressure roller 63, it presses the elastic layer of the first pressure roller 63 via the fixing belt 61, forming a fixing nip at the contact point with the fixing belt 61. The outer diameter of the second pressure roller 64 is preferably 50 mm or greater. If the outer diameter of the second pressure roller 64 is less than 50 mm, the roller's heat capacity cannot be ensured, and the printing speed of the image forming apparatus 10 cannot be increased. The type of heater 66 is not particularly limited. Examples of types of heater 66 include a halogen heater and an electromagnetic induction coil. In this embodiment, the heater 66 is a halogen heater disposed inside the heating roller 62.

[0026] The first temperature sensor 67 is a device for detecting the temperature of the fixing member 61 heated by the heating roller 62. The second temperature sensor 68 is a device for detecting the temperature of the outer peripheral surface of the second pressure roller 64.

[0027] The airflow separating device 69 is a device that generates an airflow from the downstream side in the moving direction of the fixing member 61 toward the fixing nip portion, thereby promoting separation of the recording medium S from the fixing member 61.

[0028] The guide plate 70 is a member for guiding the recording medium S having an unfixed toner image to the fixing nip portion. The guide roller 71 is a member for guiding the recording medium S having the fixed toner image from the fixing nip portion to the outside of the image forming apparatus 10.

[0029] The recording medium transport section 80 has three paper feed tray units 81 and multiple registration roller pairs 82. The paper feed tray units 81 accommodate recording media S (standard paper, special paper, etc. in this embodiment) identified based on basis weight, size, etc., by preset type. The registration roller pairs 82 are arranged to form a desired transport path.

[0030] In this image forming apparatus 10, a toner image is formed on the recording medium S sent by the recording medium conveying unit 80 at the intermediate transfer unit 40 based on image data acquired by the image reading unit 20. The recording medium S on which the toner image has been formed at the intermediate transfer unit 40 is sent to the fixing device 60.

[0031] Fixing member 61 in fixing device 60 is driven to rotate at a predetermined speed and is heated to a desired temperature (e.g., 190°C) by heater 65 under feedback control by first temperature sensor 67. Second pressure roller 64 is heated to a desired temperature (e.g., 180°C) by heater 66 under feedback control by second temperature sensor 68. Then, in synchronization with the arrival of recording medium S, second pressure roller 64 presses the outer peripheral surface of first pressure roller 63 via fixing member 61 to form a fixing nip portion.

[0032] Meanwhile, the recording medium S bearing an unfixed toner image is guided by guide plate 70 to the fixing nip portion. Then, as fixing member 61 comes into close contact with recording medium S, the unfixed toner image is quickly fixed to recording medium S. Furthermore, recording medium S receives an airflow from airflow separating device 69 at the downstream end of the fixing nip portion. This promotes separation of recording medium S from fixing member 61. The recording medium separated from fixing member 61 is guided by guide roller 71 toward the outside of image forming apparatus 10.

[0033] (Configuration of fixing belt) Next, a detailed description will be given of the fixing member 61. Figure 3A is a perspective view of the fixing member 61, and Figure 3B is an enlarged view of an area A shown in Figure 3A.

[0034] 3A and 3B, the fixing member 61 has a base layer 61a, an elastic layer 61b, and a surface layer 61c. In the fixing member 61, the base layer 61a is located on the inner side, and the surface layer 61c is located on the outer side.

[0035] The base layer 61a is made of a heat-resistant resin. The heat-resistant resin can be appropriately selected from resins that do not denature or deform within the operating temperature range of the fixing member 61. Examples of heat-resistant resins include polyphenylene sulfide, polyarylate, polysulfone, polyethersulfone, polyetherimide, polyimide, polyamideimide, and polyetheretherketone. From the viewpoint of heat resistance, polyimide is preferred as the heat-resistant resin. One type of heat-resistant resin may be used alone, or two or more types may be used in combination.

[0036] Polyimide can be obtained by heating its precursor, polyamic acid, at a temperature of 200°C or higher, or by dehydrating and cyclizing (imidizing) the polyamic acid using a catalyst. Polyamic acid can be produced by dissolving a tetracarboxylic dianhydride and a diamine compound in a solvent, mixing, and heating to cause a polycondensation reaction, or by using a commercially available product. Examples of diamine compounds and tetracarboxylic dianhydrides include the compounds described in paragraphs 0123 to 0130 of JP 2013-25120 A.

[0037] The base layer 61a may further contain components other than the heat-resistant resin as long as the effects of this embodiment are obtained. The content of the heat-resistant resin in the material of the base layer 61a is preferably 40 to 100% by volume from the viewpoint of moldability, etc.

[0038] The elastic layer 61b is made of a heat-resistant elastic material. The elastic layer 61b is disposed on the base layer 61a. Examples of materials for the elastic layer 61b include elastic resin materials such as silicone rubber, thermoplastic elastomer, and rubber materials. The material for the elastic layer 61b is preferably silicone rubber.

[0039] Examples of silicone rubbers include polyorganosiloxanes or heat-cured products thereof, and the addition reaction type silicone rubber described in JP 2009-122317 A. Examples of polyorganosiloxanes include dimethylpolysiloxanes having both ends blocked with trimethylsiloxane groups and having vinyl groups on the side chains described in paragraph 0029 of JP 2008-255283 A. One type of silicone rubber may be used alone, or two or more types may be used in combination.

[0040] The content of the elastic resin material in the elastic material is preferably 60 to 100% by volume, more preferably 75 to 100% by volume, and even more preferably 80 to 100% by volume.

[0041] The thickness of the elastic layer 61b is preferably 30 to 400 μm, more preferably 50 to 300 μm, and even more preferably 100 to 250 μm, from the viewpoint of sufficiently exhibiting heat conductivity and elasticity.

[0042] The elastic layer 61b may further contain components other than the elastic resin material as long as the effects of this embodiment are achieved. For example, the elastic material may further contain a thermally conductive filler to enhance the thermal conductivity of the elastic layer. Examples of filler materials include silica, metallic silica, alumina, zinc, aluminum nitride, boron nitride, silicon nitride, silicon carbide, carbon, and graphite. The form of the filler is not limited and may be, for example, a spherical powder, an irregular powder, a flat powder, or a fiber.

[0043] The surface layer 61c has an appropriate releasability for toner. The surface layer 61c is disposed on the elastic layer 61b. The surface layer 61c is located on the outer surface of the fixing member 61 that contacts the recording medium S during fixing. The surface layer 61c contains a resin but does not contain a fluorine compound or a silane compound. The surface layer 61c has a hexadecane contact angle of 25° or greater at 150°C. Examples of resins that satisfy the above conditions include polymethylpentene, silicone rubber, and various heat-resistant resins. From the viewpoint of the fixability of the toner image, polymethylpentene is preferred as the resin.

[0044] Examples of fluorine compounds that cannot be contained in the surface layer 61c include perfluoropolymers having a fluorine-containing alicyclic structure in the main chain, fluoropolymers copolymerized with a monomer having a methylene group in the molecule and a highly fluorinated monomer, and fluoropolymers in which a crystalline fluorine-containing segment is graft-polymerized onto a main chain having a structure similar to that of a fluorine-containing elastomer. Examples of copolymerization components of fluorine compounds include perfluorovinyl monomers such as tetrafluoroethylene (TFE), hexafluoropropylene (HFP), vinylidene fluoride (VDF), and perfluoroalkyl vinyl ether. Specific examples of such fluorine compounds include polytetrafluoroethylene (PTFE), perfluoroalkoxy fluororesin (PFA), tetrafluoroethylene and ethylene copolymer (ETFE), and polyvinylidene fluoride (PVDF).

[0045] The silane compound that cannot be contained in the surface layer 61c includes, for example, a compound represented by the following chemical formula (1).

[0046] [ka]

[0047] In the formula, R1 represents a hydrocarbon group, and X1, X2, and X3 each independently represent an alkyl group, an alkenyl group, an aryl group, a heteroaryl group, or a group having a structure represented by the following chemical formula (2).

[0048] [ka]

[0049] R2 and R3 each independently represent an alkyl group, an alkenyl group, an aryl group, or a heteroaryl group.

[0050] Examples of the hydrocarbon group represented by R1 include an alkyl group, an alkenyl group, an alkynyl group, and an aryl group. The hydrocarbon group is preferably a linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms.

[0051] Examples of the alkyl group of X1, X2, and X3 include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, and an isopentyl group. Other examples of the alkyl group include a neopentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, a 2-ethylhexyl group, a cyclopropyl group, a cyclopentyl group, and a cyclohexyl group.

[0052] Examples of the alkenyl group of X1, X2 and X3 include a vinyl group, an allyl group, a propenyl group, an isopropenyl group, a butenyl group, a hexenyl group, a cyclohexenyl group and an octenyl group.

[0053] Examples of aryl groups for X1, X2, and X3 include non-condensed hydrocarbon groups such as phenyl, biphenyl, and terphenyl; pentalenyl, indenyl, naphthyl, azulenyl, heptalenyl, and biphenylenyl. Other examples of aryl groups include fluorenyl, acenaphthylenyl, pleiadenyl, acenaphthenyl, phenalenyl, phenanthryl, and anthryl. Other examples of aryl groups include fluoranthenyl, acephenanthrylenyl, aceanthryllenyl, triphenylenyl, pyrenyl, chrysenyl, and naphthacenyl.

[0054] Examples of the heteroaryl group for X1, X2 and X3 include a pyridyl group, a pyrimidinyl group, a furyl group, a pyrrolyl group, an imidazolyl group, a benzimidazolyl group, a pyrazolyl group, a pyrazinyl group and a triazolyl group.

[0055] The alkyl group, alkenyl group, aryl group, or heteroaryl group of R2 and R3 includes the same groups as the alkyl group, alkenyl group, aryl group, or heteroaryl group of X1, X2, and X3, respectively.

[0056] R1, R2, R3, X1, X2, and X3 may be further substituted with a substituent. Examples of the substituent include an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, a heterocyclic group, an alkoxy group, a cycloalkoxy group, an aryloxy group, an alkylthio group, a cycloalkylthio group, and an arylthio group. Other examples of the substituent include an alkoxycarbonyl group, an aryloxycarbonyl group, a sulfamoyl group, an acyl group, an acyloxy group, an amido group, a carbamoyl group, a ureido group, a sulfinyl group, and an alkylsulfonyl group. Other examples of the substituent include an arylsulfonyl group or a heteroarylsulfonyl group, an amino group, a halogen atom, a fluorohydrocarbon group, a cyano group, a nitro group, a hydroxy group, a mercapto group, a silyl group, a phosphono group, a carboxy group, and a sulfo group.

[0057] Specific examples of these include trifunctional organosilanes. Examples of trifunctional organosilanes include methyltrimethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, isopropyltrimethoxysilane, n-butyltrimethoxysilane, and isobutyltrimethoxysilane. Other examples of trifunctional organosilanes include n-hexyltrimethoxysilane, n-octyltrimethoxysilane, n-decyltrimethoxysilane, n-dodecyltrimethoxysilane, and n-tetradecyltrimethoxysilane. Other examples of trifunctional organosilanes include n-hexadecyltrimethoxysilane, n-octadecyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, and n-propyltriethoxysilane. Other examples of trifunctional organosilanes include isopropyltriethoxysilane, n-butyltriethoxysilane, isobutyltriethoxysilane, n-hexyltriethoxysilane, n-octyltriethoxysilane, and n-decyltriethoxysilane.Other examples of trifunctional organosilanes include n-dodecyltriethoxysilane, n-tetradecyltriethoxysilane, n-hexadecyltriethoxysilane, and n-octadecyltriethoxysilane.

[0058] The thickness of the surface layer 61c is preferably 5 to 40 μm, more preferably 10 to 35 μm, and even more preferably 15 to 30 μm, from the viewpoints of heat transfer, conformity to deformation of the elastic layer 61b, and releasability.

[0059] The surface layer 61c may further contain other components as long as the effects of this embodiment are achieved. For example, the surface layer 61c may further contain lubricant particles or carbon black. Examples of lubricant particles include silicone resin particles and silica particles.

[0060] The resin content in the material of the surface layer 61c is preferably 70 to 100% by volume from the viewpoints of heat conductivity and flexibility that can sufficiently follow the deformation of the elastic layer.

[0061] As described above, the contact angle of the surface layer with hexadecane at 150°C is 25° or more. If the contact angle with hexadecane is less than 25°C, separation and fixation are not achieved. If the contact angle with hexadecane is not 25°C or more, the surface layer 61c and the recording medium do not separate, and if the temperature at that time is not 150°C or more, the toner does not melt and a suitable image cannot be obtained.

[0062] The hexadecane contact angle can be measured, for example, by the following method: Using an automatic contact angle meter Dmo-602 (Kyowa Interface Science Co., Ltd.), 2 μL of n-hexadecane was dropped onto the surface of surface layer 61c in an environment of 150° C. using a contact angle measurement liquid, and the hexadecane contact angle was measured after 5 seconds.

[0063] The melting point of the surface layer 61c is preferably 225° C. or higher and 280° C. or lower. If the melting point of the surface layer 61c is lower than 225° C., there is a risk that the surface layer 61c may melt during use in the image forming apparatus 10.

[0064] The melting point of the surface layer 61c can be measured by the following method: The melting point of the surface layer 61c can be measured at 2°C / min using a differential scanning calorimeter (DSC-60: Shimadzu Corporation) and confirmed from the melting peak.

[0065] The yield point stress of the surface layer 61c is preferably 20 MPa or more and 80 MPa or less. If the yield point stress of the surface layer 61c is not within the above range, the fixing member 61 may not properly follow the recording medium.

[0066] The yield point stress of the surface layer 61c can be measured, for example, by the following method: The yield point stress was measured in accordance with ISO527 using a tensile tester (AGS-X: Shimadzu Corporation).

[0067] The fixing member 61 may further include layers other than the base layer 61a, the elastic layer 61b, and the surface layer 61c described above, as long as the effects of the present embodiment can be obtained. Examples of the other layers include a reinforcing layer.

[0068] The reinforcing layer is a layer for increasing the mechanical strength of the fixing member 61, and is disposed, for example, on the surface (the inner peripheral surface of the base layer 61a) opposite to the elastic layer 61b and the surface layer 61c of the fixing member 61. The reinforcing layer can be made of the heat-resistant resin described above, and its thickness can be determined appropriately.

[0069] The fixing member 61 of this embodiment can be produced using a known method for producing a laminated fixing belt. The method for producing the fixing member 61 includes the steps of covering the outer surface of the endless base layer 61a made of heat-resistant resin with a tube that will become the surface layer 61c, injecting an elastic material or its precursor between the molded body and the tube, and, if necessary, heating and curing the elastic material or precursor.

[0070] (effect) As described above, the fixing member 61 according to the present embodiment has a surface layer that does not contain fluorine compounds or silane compounds, and the contact angle of the surface layer with hexadecane at 150°C is 25° or more, and therefore has excellent fixing properties and separability.

[0071] [Embodiment 2] Next, an image forming apparatus according to embodiment 2 will be described. The image forming apparatus according to this embodiment differs from the image forming apparatus 10 according to embodiment 1 only in the configuration of the fixing device 60. Therefore, the same components as those in embodiment 1 are denoted by the same reference numerals and their description will be omitted.

[0072] Fig. 4 is a schematic diagram showing the configuration of a fixing device 60 in an image forming apparatus according to Embodiment 2. As shown in Fig. 4, fixing device 60 according to the present embodiment includes a fixing member 61, a first pressure roller 63, a second pressure roller 64, a heater (heating unit) 65, a first temperature sensor 67, a second temperature sensor 68, an airflow separating device 69, a guide plate 70, and a guide roller 71.

[0073] The heater (heating unit) 65 in this embodiment is a heat source (SURF type) arranged on the rear side of the fixing member 61. The fixing member 61 may be in the shape of a roller or a plate.

[0074] (effect) As described above, fixing member 61 according to the present embodiment has the same effects as those of the first embodiment. [Example]

[0075] The present invention will be described in more detail using the following examples and comparative examples. Unless otherwise specified, all operations were carried out at room temperature (20°C). The present invention is not limited to the following examples.

[0076] [Example 1] A varnish containing polyamic acid and 8% by mass of carbon black relative to the amount of polyamic acid was applied to the outside of a cylindrical mold while rotating. It was then dried at 300-450°C and imidized to obtain a cylindrical polyimide tubular article (base layer) with an inner diameter of 99 mm, a length of 360 mm, and a thickness of 70 μm. The polyamic acid used was a polymer obtained by dehydration condensation of 3,3',4,4'-biphenyltetracarboxylic dianhydride and p-phenylenediamine.

[0077] Polymethylpentene (DX845: Mitsui Chemicals, Inc.) was fed into a single-screw extruder (Toyo Seiki Seisakusho, Ltd.) to obtain a 30 μm-thick polymethylpentene tubular product (surface layer).

[0078] A cylindrical stainless steel core with an outer diameter of 99 mm was attached to the inside of the base layer, and a cylindrical mold was placed on the outside of the base layer, holding a 30 μm-thick polymethylpentene tubular material (surface layer) on its inner surface. In this way, the core and the cylindrical mold were held coaxially, and a cavity (gap) was formed between them. Next, a silicone rubber material was injected into the cavity and cured by heating.

[0079] Through the above steps, a fixing belt 1 of Example 1 was obtained, which had a 200 μm-thick elastic layer made of silicone rubber and a surface layer (polymethylpentene tubular member) on a base layer (polyimide tubular member).

[0080] The hexadecane contact angle at 150° C., melting point and yield point stress of the surface layer were measured by the methods described above.

[0081] [Example 2] A fixing belt 2 of Example 2 was obtained in the same manner as in Example 1, except that polymethylpentene (DX845) in Example 1 was changed to polymethylpentene (MX004: Mitsui Chemicals, Inc.).

[0082] [Comparative Example 1] A fixing belt 3 of Comparative Example 1 was obtained in the same manner as in Example 1, except that polymethylpentene (DX845) in Example 1 was changed to polymethylpentene (MX002: Mitsui Chemicals, Inc.).

[0083] Comparative Example 2 A fixing belt 4 of Comparative Example 2 was obtained in the same manner as in Example 1, except that polymethylpentene (DX845) in Example 1 was changed to polyphenylene sulfide (A900: Toray Industries, Inc.).

[0084] [Separability evaluation] An image forming apparatus was prepared in which a fixing device equipped with each of the manufactured fixing belts was installed in the fixing device of a full-color production printer "Accurio Press C3070" (Konica Minolta, Inc.). Using each image forming apparatus, color copy paper (basis weight 90 / m²) was used as A4 plain paper. 2 Using a printer (manufactured by Mondi), a two-layer solid image (red) of cyan and magenta with a margin of 1 mm at the leading edge of the image was printed as the output image, and the separation air volume was reduced to 30% of the setting, and the paper feed state of the color copy paper was visually observed. Separation was evaluated according to the following criteria. A: Plain paper separated without curling. B: Plain paper curls a little, but it's not a problem. C: Wrinkles on plain paper D: Plain paper could not be separated

[0085] [Evaluation of fixation] Using each of the prepared image forming devices, A4 gloss coated paper (paper thickness: 140 μm, basis weight: 128 g / m 2 ) (POD Gloss Coat 128: Oji Paper Co., Ltd.) A cyan solid image was output as the output image, and the toner image was visually observed. Fixability was evaluated according to the following criteria. A: No defects due to poor fixing were found in the cyan solid image. B: Minor fixing defects were observed here and there, but were at a level that did not pose a problem in practical use. C: Clear defects due to poor fixing were observed in the cyan solid image. D: The formed toner image could not be separated, so the fixability could not be evaluated.

[0086] Table 1 shows the physical properties and evaluation results of each fixing belt.

[0087] [Table 1]

[0088] As shown in Table 1, fixing belts 1 and 2 of Examples 1 and 2, which had a hexadecane contact angle of more than 25°, exhibited good separation properties and fixing properties. Furthermore, the fixing belt 1 of Example 1, which had a large hexadecane contact angle, a high melting point, and a large yield point stress, had better fixing properties than the fixing belt 2 of Example 2. This is thought to be because the high hexadecane contact angle made it easier for the toner image to be pressed onto the belt.

[0089] On the other hand, in the fixing belts 3 and 4 of Comparative Examples 1 and 2, which had a hexadecane contact angle of 25° or less, the separation property and fixation property were poor. This is thought to be because the small hexadecane contact angle reduced the viscosity of the toner, making it impossible to fix the toner image. [Industrial Applicability]

[0090] According to the present invention, it is expected that electrophotographic image forming apparatuses will be able to achieve higher speeds, higher performance, and more energy savings, and that image forming apparatuses will become more widespread. [Explanation of symbols]

[0091] 10 Image forming device 20 Image reading unit 21 Paper feeder 22 Scanner 23 CCD sensors 24 Image processing section 30 Image forming unit 31 Image forming unit 32 Photosensitive drum 33 Charging device 34 Exposure equipment 35 Developing device 36 Cleaning device 40 Intermediate transfer unit 41 Primary transcription unit 42 Secondary transfer unit 43 Intermediate transfer belt 44 Primary transfer roller 45 Backup roller 46 First support roller 47 Cleaning Device 48 Secondary transfer belt 49 Secondary transfer roller 50 Second support roller 60 Fixing device 61 Fixing member 62 Heating roller 63 First pressure roller 64 Second pressure roller 65, 66 Heater 67 First temperature sensor 68 Second temperature sensor 69 Airflow Separator 70 Signboard 71 Guide roller 80 Recording medium transport unit 81 Paper feed tray unit 82 Registration roller pair D Manuscript S Paper (recording medium)

Claims

1. a surface layer containing a resin and not containing a fluorine compound or a silane compound; The surface layer has a hexadecane contact angle of 25° or more at 150°C. Fixing member.

2. The melting point of the surface layer is 225°C or higher and 280°C or lower, The yield point stress of the surface layer is 20 MPa or more and 80 MPa or less. The fixing member of claim 1 .

3. 2. The fuser member of claim 1, wherein the resin is polymethylpentene.

4. a base layer comprising polyimide; an elastic layer including silicone rubber disposed on the base layer; the surface layer disposed on the elastic layer; having The fixing member of claim 1 .

5. The fixing member has an endless belt shape. The fixing member according to claim 4 .

6. The fixing member according to claim 5 ; a plurality of rollers that pivotally support the fixing member; a heating section for heating the fixing member; having Fixing device.

7. 7. The fixing device according to claim 6, wherein the heating section is a heat source disposed on the rear side of the fixing member, a halogen heater disposed inside the roller, or an electromagnetic induction coil disposed inside the roller.

8. 8. An image forming apparatus comprising the fixing device according to claim 6, which fixes an unfixed toner image formed on a recording medium by electrophotography onto the recording medium by applying heat and pressure.

Images