Rotating body for pressure application and manufacturing method thereof, fixing device, and electrophotographic image forming apparatus

Abstract

To provide a rotating body for pressure application and the like that achieve durability of a surface layer and excellent heat insulating properties at a high level.SOLUTION: A rotating body for pressure application has a base layer, an elastic layer, and a surface layer in this order. The surface layer has holes. In observation of a 8-μm vertical and 11-μm horizontal area on a cross section in a direction orthogonal to the thickness of the surface layer and the circumferential direction of the rotating body for pressure application, the holes have a degree of orientation f of 0.20 or more and an orientation angle Φ of 0° or more and 10° or less.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a pressure rotating member and a manufacturing method thereof, a fixing device, and an electrophotographic image forming apparatus. [Background technology]

[0002] An example of a fixing device used in an electrophotographic image forming apparatus (hereinafter also referred to as an "image forming apparatus") such as a copier or laser printer includes a fixing device having a heating rotor and a pressure rotor placed in pressure contact with the heating rotor. In such a fixing device, paper carrying an unfixed toner image is introduced into the nip formed by the heating rotor and the pressure rotor, and the toner is heated and pressurized to fix the image to the paper. The pressure rotor may be called a pressure roller if it has a roller shape, or a pressure belt if it has an endless belt shape.

[0003] Here, Patent Document 1 discloses a pressure member for fixing, which is used as a pressure rotating body, and which is composed of a layer having a surface made of a fluororesin and an outer shell made of an inorganic material, the layer containing 10 parts by weight or more of hollow particles per 100 parts by weight of the fluororesin. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-232208 [Non-patent literature]

[0005] [Non-Patent Document 1] IEEE Transactions on SYSTEMS, MAN, AND CYBERNETICS, vol. SMC-9, No.1, Jan 1979, pp. 62-66 Summary of the Invention [Problem to be solved by the invention]

[0006] The pressure member disclosed in Patent Document 1 has a surface layer containing a fluororesin and hollow particles that make it porous, which is expected to suppress toner adhesion to the surface and heat transfer from the heating member to the pressure member. In response to demands for further shortening the start-up time (First Print Out Time; FPOT) of electrophotographic devices, further improvements in the heat insulation of pressure members are becoming necessary. It was thought that improving the heat insulation of the surface layer that constitutes the surface of the pressure member that directly contacts paper (hereinafter also referred to as the "outer surface") would be effective in further shortening FPOT. Therefore, the present inventors investigated increasing the porosity by increasing the amount of hollow particles in the surface layer of the pressure applying member disclosed in Patent Document 1 or by using hollow particles with a large particle diameter. However, as a result, the strength of the surface layer of the pressure applying member decreased, and cracks and breaks sometimes occurred in the surface layer after long-term use. From this, the present inventors recognized that in order to further improve the heat insulating properties while maintaining the durability of the surface layer of the pressure applying rotor, it was necessary to develop a technology for a pressure applying rotor having a configuration that can improve the heat insulating properties of the surface layer by a method other than the inclusion of hollow particles.

[0007] One aspect of the present disclosure is directed to providing a pressure rotating body that can achieve both high levels of durability of the surface layer and excellent heat insulation. Another aspect of the present disclosure is directed to providing a fixing device that contributes to shortening the startup time. Still another aspect of the present disclosure is directed to providing an image forming apparatus that has a shorter startup time than conventional apparatuses. Yet another aspect of the present disclosure is directed to providing a pressure rotating body that can achieve high levels of durability of the surface layer and excellent heat insulation. The present invention aims to provide a method for manufacturing a pressurizing rotor that can achieve both high levels of durability of the surface layer and excellent heat insulation properties. [Means for solving the problem]

[0008] According to one aspect of the present disclosure, A pressurizing rotor having a base layer, an elastic layer, and a surface layer in this order, the surface layer has pores, The thickness of the surface layer is observed in an area of ​​8 μm length x 11 μm width in a cross section perpendicular to the circumferential direction of the pressurizing rotor. The degree of orientation f of the pores is 0.20 or more, The orientation angle Φ is between 0° and 10° A rotating pressurizing body is provided. According to another aspect of the present disclosure, there is provided a fixing device including the above-described fixing rotator, a fixing belt, and a heating unit for the fixing belt. According to another aspect of the present disclosure, there is provided an electrophotographic image forming apparatus including the above-described fixing device.

[0009] According to yet another aspect of the present disclosure, A method for manufacturing a pressurizing rotor having a base layer, an elastic layer, and a surface layer in this order, the surface layer having pores, (i) preparing a resin tube manufactured by cylindrical extrusion molding; (ii) a step of obtaining a laminate of an endless belt-shaped or roller-shaped substrate, an elastic layer covering the outer peripheral surface of the substrate, and the resin tube covering the outer peripheral surface of the elastic layer; (iii) immersing the laminate in perfluoropolyether to impregnate the resin tube with the perfluoropolyether; and (iv) removing the perfluoropolyether impregnated in the resin tube of the laminate obtained in the step (iii) from the resin tube using a solvent to form pores in the resin tube, thereby forming the surface layer; A method for manufacturing a pressurizing rotor having the above structure is provided. [Effects of the Invention]

[0010] According to one aspect of the present disclosure, a pressure rotating body can be obtained that can achieve both high levels of durability of the surface layer and excellent heat insulation. According to another aspect of the present disclosure, a fixing device that contributes to shortening start-up time can be obtained. According to yet another aspect of the present disclosure, an image forming apparatus that has a shorter start-up time than conventional apparatuses can be obtained. According to yet another aspect of the present disclosure, a method for manufacturing a pressure rotating body that can achieve both high levels of durability of the surface layer and excellent heat insulation can be obtained. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram showing a method for confirming the degree of orientation f and the orientation angle Φ of pores. [Figure 2] 1 is an image of a cross section of the surface layer of the pressurizing rotor described in Example 1, the cross section being parallel to the longitudinal direction of the pressurizing rotor. [Figure 3] FIG. 2 is a cross-sectional view of one embodiment of a pressurizing rotor. [Figure 4] FIG. 1 is a cross-sectional view of an embodiment of a fixing device using a pressure rotating member. [Figure 5] 1 is a schematic diagram illustrating one embodiment of an electrophotographic image forming apparatus. DETAILED DESCRIPTION OF THE INVENTION

[0012] The expressions "XX or more and YY or less" or "XX to YY" that represent a numerical range mean a numerical range including the endpoints, that is, the lower limit and the upper limit, unless otherwise specified. When a numerical range is stated in stages, the upper and lower limits of each numerical range may be combined in any combination. It can be done. In addition, in the present disclosure, the "longitudinal direction" refers to a direction perpendicular to the circumferential direction of the pressurizing rotor.

[0013] The present inventors conducted extensive research to obtain a pressurizing rotor that can achieve both high levels of durability and heat insulation in the surface layer. As a result, they discovered that orienting the pores in the surface layer so that the pore orientation degree f and orientation angle Φ observed in a cross section perpendicular to the thickness of the surface layer and the circumferential direction of the pressurizing rotor exhibit specific values ​​can reduce the thermal conduction in the thickness direction of the surface layer while suppressing a decrease in the strength of the surface layer.

[0014] That is, a pressurizing rotor according to one aspect of the present disclosure has a base layer, an elastic layer, and a surface layer in this order, the surface layer has pores, The degree of orientation f of the pores observed in an observation area of ​​8 μm vertical x 11 μm horizontal in a cross section perpendicular to the thickness of the surface layer - circumferential direction of the pressurizing rotor is 0.20 or more, and the orientation angle Φ is 0° or more and 10° or less.

[0015] When the degree of orientation f and the orientation angle Φ of the pores observed in the observation area are within the above ranges, the pores are present in the surface layer in a layered manner in the longitudinal direction of the pressurizing rotor (see Figure 2). This configuration can effectively block the flow of heat from the surface of the pressurizing rotor facing the surface layer toward the base layer of the pressurizing rotor. Therefore, it is possible to improve the thermal insulation of the surface layer in the thickness direction while avoiding an excessive increase in the porosity in the surface layer, which would reduce the strength of the surface layer. An embodiment of the pressurizing rotor according to the present disclosure will be described below.

[0016] 1. Rotating body for pressure application The pressurizing rotor has a base layer, an elastic layer, and a surface layer in this order. FIG. 3 is a cross-sectional schematic diagram of one embodiment of a pressurizing rotor (hereinafter referred to as "pressurizing rotor 19"). Pressurizing rotor 19 has a cylindrical elastic layer 19b formed on the outer peripheral surface of a cylindrical or columnar base layer 19a and concentric with base layer 19a. The outer peripheral surface of elastic layer 19b is covered with a surface layer 19c serving as the outermost layer. Note that elastic layer 19b may be bonded to the outer peripheral surface of base layer 19a with an adhesive layer (not shown). Furthermore, surface layer 19c may be bonded to the outer peripheral surface of elastic layer 19b with an adhesive layer (not shown). The shape of the pressure rotating body is not particularly limited, and may be, for example, a pressure belt having an endless belt shape, or a pressure roller having a roller shape.

[0017] 1-1. Base layer The base layer 19a is preferably made of iron or aluminum. The surface of the base may be activated in advance by sandblasting or the like, and may be degreased with methylene chloride, a hydrocarbon-based cleaner, or a water-based cleaner. When the elastic layer 19b containing silicone rubber is provided on the surface of the base layer 19a, it is preferable to apply a primer treatment to the surface of the base layer 19a in order to improve the adhesion between the base layer 19a and the elastic layer 19b. The primer used in the primer treatment may be, for example, a paint in which a silane coupling agent, a silicone polymer, a hydrogenated methylsiloxane, an alkoxysilane, a reaction-accelerating catalyst, and a colorant such as red iron oxide are appropriately mixed and dispersed in an organic solvent. The primer can be appropriately selected depending on the material of the base layer 19a, the type of the elastic layer 19b, or the type of crosslinking reaction. In particular, when the elastic layer 19b contains a large amount of unsaturated aliphatic groups, a primer containing a hydrosilyl group is preferably used to impart adhesiveness by reacting with the unsaturated aliphatic groups. When the elastic layer 19b contains a large amount of hydrosilyl groups, a primer containing an unsaturated aliphatic group is preferably used. Other examples of primers include those containing alkoxy groups. Commercially available primers can be used. The primer treatment includes applying the primer to the outer surface of the base layer 19a (the surface to be bonded to the elastic layer 19b) and drying or baking the primer. As the primer, commercially available products can be used, specifically, a mixture of equal amounts of "liquid A" and "liquid B" of DY35-051 manufactured by Toray Down Corning Co., Ltd. can be used.

[0018] 1-2.Elastic layer The material of the elastic layer 19b is not particularly limited, and any known material used for the elastic layer of a pressure rotating body can be used. The elastic layer 19b is a layer for forming the fixing nip portion N described later in "2. Fixing device," and may be a solid rubber layer or a foam rubber layer. The thickness of the elastic layer 19b used in the pressure rotating body 19 is not particularly limited as long as it is thick enough to form a fixing nip portion N of the desired width, but is preferably 2 mm to 10 mm. Any of the following may be suitably used as the main polymer of the elastic layer 19b. For example, high temperature vulcanizing silicone rubber (HTV; High Temperature Vulcanizing), addition reaction curing silicone rubber (LTV; Low Temperature Vulcanizing), condensation reaction curing silicone rubber (RTV; Room Temperature Vulcanizing), Examples of suitable materials include additives such as temperature vulcanizing (TVV), addition-type liquid conductive silicone rubber, fluororubber, and mixtures thereof. Specifically, examples include silicone rubbers such as dimethylsilicone rubber, fluorosilicone rubber, methylphenylsilicone rubber, and vinylsilicone rubber, as well as fluororubbers such as vinylidene fluoride rubber, tetrafluoroethylene-propylene rubber, tetrafluoroethylene-perfluoromethylvinyl ether rubber, phosphazene-based fluororubber, and fluoropolyether. Commercially available main polymers can be used, such as a mixture of equal amounts of "liquid A" and "liquid B" from DY35-1349SC manufactured by Dow Corning Toray Co., Ltd. These main polymers can be used alone or in combination of two or more. If desired, the main polymer may be provided with reinforcing fillers such as carbon black and wet or dry silica, or with extending fillers such as calcium carbonate and quartz powder.

[0019] An adhesive layer may be formed on the outer periphery of the elastic layer 19b, which may be, for example, an addition-curing silicone rubber adhesive such as a mixture of equal parts of "liquid A" and "liquid B" of SE1819CV manufactured by Dow Corning Toray Co., Ltd., but is not limited to this. The adhesive layer may also contain an antistatic agent such as potassium pentafluoroethanesulfonate. When an antistatic agent is used, the amount of the antistatic agent added may be 0.1 to 5 parts by mass per 100 parts by mass of the adhesive used in the adhesive layer. Furthermore, the thickness of the adhesive layer formed on the outer periphery of the elastic layer 19b can be set to, for example, 0.5 μm to 20 μm.

[0020] 1-3.Surface layer The surface layer 19c has pores. Surface layer thickness: The degree of orientation f of pores observed in an area of ​​8 μm length x 11 μm width in the longitudinal cross section of the pressurizing rotor is 0.20 or more, and the orientation angle Φ is 0° or more and 10° or less. The orientation angle Φ and the degree of orientation f of the pores calculated by the following method are parameters that represent the direction and degree of orientation of the pores in the surface layer in the longitudinal direction.

[0021] 1-3-1. Calculation method for orientation angle Φ and orientation degree f of pores in the surface layer From the pressurizing rotor, a sectioning device (for example, a cryo-ultramicrotome (trade name, Using a cutting tool (manufactured by Leica Microsystems), a sample is cut out so that the cross section of the thickness of the pressure rotor minus the longitudinal direction of the pressure rotor is exposed on the surface. If necessary, a portion of the cross section corresponding to the entire thickness of the surface layer is polished using an ion beam. For example, a cross-section polisher can be used to polish the cross section using an ion beam. Next, the cross section is observed with a scanning electron microscope, and an image (SEM image) of a rectangular observation area measuring 8 μm in length and 11 μm in width is obtained at a predetermined position on the cross section. At this time, the vertical direction of the image is adjusted so that it is parallel to the thickness direction of the surface layer and the horizontal direction is parallel to the longitudinal direction of the pressurizing rotor. The resolution is set to a value (e.g., 717 pixels x 986 pixels) that allows for the analysis of voids appearing in the cross section. 2 is an enlarged schematic diagram of a portion of the SEM image, showing voids 202 present in the resin portion 201 of the surface layer. Note that the voids in the surface layer according to one embodiment of the present disclosure, which are produced by the method described below, do not have shells as shown in FIG. 2, and the walls of the voids are composed of the resin portion 201 of the surface layer.

[0022] The obtained SEM image is subjected to a binarization process using numerical calculation software (product name: MATLAB (registered trademark); manufactured by MathWorks) to make it possible to distinguish the two regions corresponding to the resin portion 201 and the voids 202. For the binarization process, the Otsu method described in Non-Patent Document 1 is used. Using the above numerical calculation software, a two-dimensional Fourier transform analysis is performed on the binarized image obtained by the binarization process, the power spectrum is integrated for each direction, and a plot showing the direction and degree of void orientation is obtained (Figure 1). Since the two-dimensional Fourier transform has a peak in the direction perpendicular to the periodicity of the image, when a two-dimensional Fourier transform is performed on an image of a thickness-longitudinal cross section, the 90°-270° direction indicates the longitudinal direction of the surface layer. In this plot, the angle (greater than or equal to 0° and less than 90°) that the longest diameter makes with the 90°-270° direction is taken as the orientation angle Φ. The closer the orientation angle Φ is to 0°, the more pores are oriented in the longitudinal direction. In other words, the orientation angle Φ is a parameter that represents the direction of orientation of pores in the longitudinal direction.

[0023] Furthermore, when the length of the line segment of the longest diameter is x and the length of the line segment perpendicular to the longest diameter is y, the degree of orientation f is f = 1 - (y / x). Figure 1 shows how to confirm the orientation angle Φ and the degree of orientation f. The degree of orientation f is a value greater than or equal to 0.00 and less than 1.00. When the pores are in a completely random state with no orientation, the degree of orientation f is 0.00, and as the degree of orientation of the pores increases, the degree of orientation f approaches 1.00. In other words, the degree of orientation is a parameter that represents the degree of orientation of the pores in the longitudinal direction. Here, SEM images are taken from the cross section of the sample at the following three locations: in the fixing device, the upper end of the observation area is 1 μm in the depth direction from the outer surface of the surface layer that forms the outer surface of the pressure rotating body that constitutes the contact surface with the heating rotating body; the lower end of the observation area is 1 μm from the surface opposite to the outer surface of the surface layer (the surface facing the base layer) toward the outer surface; and the center of the thickness direction of the surface layer coincides with the center of the observation area. 26 If the difference is less than μm, the acquisition position is adjusted so that the observation regions do not overlap each other. The orientation angle and degree according to the present disclosure are the average values ​​obtained from the SEM images of the observation regions acquired from the above three locations.

[0024] In a pressurizing rotor according to one embodiment of the present disclosure, the orientation angle Φ is 10° or less, preferably 7° or less, and more preferably 5° or less. The orientation angle Φ is 0° or greater, but may be, for example, 1° or greater or 2° or greater. Therefore, for example, the orientation angle Φ is preferably in the range of 0° or greater to 10° or less, more preferably 1° or greater to 7° or less, and particularly preferably 2° or greater to 5° or less. The degree of orientation f is 0.20 or more, preferably 0.25 or more, and more preferably 0.30 or more. The upper limit of the degree of orientation f is not particularly limited, and the higher the value, the better. For example, 1.0 It may be less than 0, 0.80 or less, or 0.60 or less. Thus, for example, the degree of orientation f is preferably in the range of 0.20 or more and less than 1.00, more preferably in the range of 0.25 or more and 0.80 or less, and particularly preferably in the range of 0.30 or more and 0.60 or less. When the longitudinal orientation angle Φ of the pores and the degree of orientation f are within the above ranges, a heat insulating effect in the thickness direction of the surface layer can be obtained due to the longitudinal orientation of the pores. A method for producing such a surface layer will be described later.

[0025] The material of the surface layer 19c is not particularly limited, and known materials used for the surface layer of a pressure rotating body can be used. Preferably, the surface layer contains a fluororesin. This can suppress toner adhesion to the surface of the pressure rotating body. In this case, the content of the fluororesin in the surface layer is preferably 60% by mass or more, and particularly 80% by mass or more, relative to the surface layer. This is because the fluororesin can further suppress toner filming on the outer surface of the pressure rotating body. The upper limit is not particularly limited, and is 100% by mass or less, and may be 95% by mass or less, taking into account the inclusion of other optional components (such as conductive fillers) in the surface layer.

[0026] Examples of such fluororesins include copolymers (hereinafter, PFA) of tetrafluoroethylene and perfluoroalkyl vinyl ether (hereinafter, PAVE). PAVEs that can be suitably used include those in which the number of carbon atoms in the perfluoroalkyl chain is 1 to 6, particularly 1 to 4, and further 1 to 3. Specific examples of PAVEs include perfluoromethyl vinyl ether (CF2=CF-O-CF3), perfluoroethyl vinyl ether (CF2=CF-O-CF2CF3), and perfluoropropyl vinyl ether (CF2=CF-O-CF2CF2CF3). Furthermore, as such PFA, the following commercially available products can be used. "451HP-J", "959HP-Plus", "350-J", "950HP-Plus" (all product names; manufactured by Mitsui DuPont Fluorochemicals Co., Ltd.); "P-66P", "P-66PT", "P-802UP" (all product names; manufactured by AGC); "AP-230", "AP-231SH", etc. (both product names; manufactured by Daikin Corporation), - "6502N" (product name; manufactured by 3M). The melting point of PFA is usually within the range of 280°C to 320°C, for example, 290°C to 310°C.

[0027] <Method of manufacturing the pressure rotating body> A non-limiting example of a method for producing the pressure rotating body (pressure belt or pressure roller) according to one embodiment of the present disclosure, which has a base layer, an elastic layer, and a surface layer in this order, and in which the surface layer has pores, is a method including the following steps (i) to (iv). (i) preparing a resin tube manufactured by a cylindrical extrusion molding method (hereinafter also referred to as a "cylindrically extruded resin tube"); (ii) a step of obtaining a laminate of an endless belt-shaped or roller-shaped substrate, an elastic layer covering the outer peripheral surface of the substrate, and the cylindrical extruded resin tube covering the outer peripheral surface of the elastic layer; (iii) a step of immersing the laminate in perfluoropolyether heated to a temperature close to the melting point of the resin tube, thereby impregnating the resin tube with perfluoropolyether (PFPE); (iv) A step of removing the PFPE impregnated in the resin tube of the laminate obtained in the step (iii) from the resin tube using a solvent to form pores in the resin tube.

[0028] As a result of the investigations by the present inventors, it was found that a cylindrical extruded resin tube was impregnated with a liquid PFPE. They found that by removing the PFPE after the resin tube was oriented, pores having a predetermined orientation angle and degree of orientation could be formed in the resin tube.

[0029] The reason why the above method can form pores in the resin layer that are oriented to a certain extent in a direction perpendicular to the circumferential direction of the pressurizing rotor is presumed to be as follows. Note that the following description will be given taking as an example a case where a PFA tube obtained by cylindrical extrusion molding of PFA is used as the resin tube. However, the resin tube according to the present disclosure is not limited to a PFA tube. A laminate consisting of an endless belt-shaped or roller-shaped substrate, an elastic layer covering the outer peripheral surface of the substrate, and a PFA tube covering the outer peripheral surface of the elastic layer is immersed in PFPE heated to a temperature near the melting point of PFA (300°C ± 50°C (preferably 290°C to 325°C)). The heated PFPE is brought into contact with the outer peripheral surface of the PFA tube, thereby allowing the PFPE to penetrate into the PFA tube. As the amount of PFPE in the PFA tube increases, the PFPEs aggregate and bond together within the PFA tube. Here, the PF The aggregation and linkage of PE is thought to occur preferentially in the amorphous regions of PFA. Therefore, if the amorphous regions of PFA are oriented, the PFPE regions will also be oriented in the direction of the amorphous regions. In PFA tubes formed by cylindrical extrusion, the amorphous regions are oriented parallel to the extrusion direction, i.e., perpendicular to the circumferential direction of the PFA tube. Therefore, when a cylindrically extruded PFA tube is impregnated with PFPE, the PFPE regions will be oriented perpendicular to the circumferential direction of the PFA tube. Then, the PFPE in the PFA tube is removed using a solvent, forming pores in the areas where the PFPE was present in the PFA tube. Therefore, pores oriented in a direction perpendicular to the circumferential direction of the PFA tube are formed in the PFA tube. In addition, according to the study by the present inventors, the thinner the film thickness of the resin tube, the higher the pore orientation degree f can be, and the closer the orientation angle Φ can be to 0. This is thought to be because the thinner the cylindrical extruded resin tube, the more easily the amorphous region is oriented in a direction parallel to the extrusion direction. In the present disclosure, the film thickness of the resin tube can be selected as appropriate as long as the orientation degree f and orientation angle Φ according to the present disclosure are achieved, but the thickness of the resin tube that can orient the pores in the extrusion direction is preferably 12 μm to 100 μm, and more preferably 20 μm to 50 μm.

[0030] In consideration of the preferred amount of pores in the resin layer described below, the amount of perfluoropolyether impregnated into the resin tube in step (iii) is preferably 25% by mass to 60% by mass, and particularly 30% by mass to 45% by mass, based on the mass of the resin tube after impregnation with perfluoropolyether. Furthermore, the vicinity of the melting point of the resin tube in step (iii) refers to, for example, a range of Tm±50°C, where Tm is the melting point of the resin tube. When the resin tube is a PFA tube, the Tm of PFA is within the range of 280 to 320°C, and therefore the temperature of the PFPE brought into contact with the outer surface of the resin tube in step (iii) is, for example, 250 to 350°C, preferably 290 to 325°C. Furthermore, in step (iii), the higher the temperature of the PFPE and the lower the viscosity of the PFPE, the more the amount of PFPE impregnated into the resin tube can be increased. The contact time between the outer surface of the resin tube and the PFPE varies depending on the viscosity of the PFPE impregnated into the resin tube and the amount of PFPE impregnated, but is generally within the range of 20 seconds to 5 minutes, and particularly 30 seconds to 2 minutes. A sufficient amount of PFPE can be impregnated into the resin tube within this range of time to form pores. The method for contacting the resin tube with the PFPE in the preparation of the pressurizing rotor in step (iii) involves contacting the PFPE with the outer surface of the resin tube by applying the PFPE to the resin tube. Any method can be used as long as it allows contact at a temperature near the melting point. The contact between the outer surface of the resin tube and the PFPE may be carried out in a state where the base layer, the elastic layer, and the surface layer are laminated in advance, as described above, or the surface (inner surface) of the resin tube that is to be bonded to the elastic layer may be masked. The contact method may be, for example, a dipping method.

[0031] In step (iv), the laminate in which the resin tube is impregnated with PFPE is removed from the perfluoropolyether bath and cooled to room temperature, and then the PFPE impregnated in the resin tube is removed using a fluorine solvent, forming pores in the resin tube. Here, the laminate may simply be immersed in the fluorine solvent, but in order to more efficiently remove the PFPE from the resin tube, it is preferable to apply ultrasonic waves or heat the fluorine solvent. The fluorine solvent used in this step is preferably one that can dissolve PFPE but does not dissolve the resin that constitutes the resin tube. Here, the "solvent that dissolves PFPE" is, for example, a solvent that dissolves 10 g or more of PFPE per 100 g of solvent at 25° C. On the other hand, the "solvent that does not dissolve resin" is, for example, a solvent that dissolves 1 g or less of resin per 100 g of solvent at 25° C. For example, when the resin tube is a PFA tube, hydrofluoroether dissolves PFPE. On the other hand, PFA is hardly soluble in hydrofluoroether, so it is a preferred fluorine solvent. As the hydrofluoroether, for example, one commercially available under the trade name "Novec7300" (manufactured by 3M) can be used.

[0032] In the surface layer according to the present disclosure, the arithmetic mean value of the ratio of the total area of ​​pores to the area (including pores) of an observation region measuring 8 μm in length and 11 μm in width in the binarized image used to calculate the orientation angle Φ and the degree of orientation f (hereinafter also referred to as the "pore area ratio") is preferably 15% to 50%, more preferably 25% to 45%. By setting the pore area ratio within the above range, it is possible to achieve a higher level of both the strength of the pressurizing rotor according to the present disclosure and the heat insulation in the thickness direction. In order to achieve the above-mentioned void area ratio, it is preferable to impregnate a sufficient amount of PFPE into the resin tube in step (iii). The amount of PFPE impregnated into the resin tube can be adjusted, for example, by the temperature of the PFPE contacted with the outer surface of the resin tube and the viscosity of the PFPE. Specifically, the amount of PFPE impregnated into the resin tube can be increased by increasing the temperature of the PFPE contacted with the outer surface of the resin tube. In addition, the amount of PFPE impregnated into the resin tube can be increased by using a PFPE with low viscosity. However, if the viscosity of the PFPE is too low, it may be difficult to form PFPE regions by aggregation and linkage within the resin tube, possibly due to increased affinity with PFA, making it difficult to obtain a high void area ratio.

[0033] The surface layer is preferably a single layer film. Taking into consideration the ease of adjusting the pore orientation angle Φ and the degree of orientation f within the ranges of the present disclosure and the durability of the pressurizing rotor, the thickness of the surface layer is preferably 12 μm or more, more preferably 20 μm or more, and preferably 100 μm or less, more preferably 50 μm or less. The thickness of the surface layer can be, for example, 12 μm or more and 100 μm or less.

[0034] <Perfluoropolyether (PFPE)> The perfluoropolyether is not particularly limited as long as it can be impregnated into the resin tube, and any known perfluoropolyether can be used. A preferred example is PFPE having the structure shown in the following formula. The PFPE is preferably one that becomes oily at the melting point of PFA.

[0035] [ka]

[0036] In the formula, a, b, c, d, e, and f each independently represent 0 or a positive integer, satisfying 1≦a+b+c+d+e+f≦600, and at least one of a, b, c, and d is a positive integer. In addition, the order of the repeating units in the formula is not limited to the order described above.Furthermore, each repeating unit in the formula may exist in a plurality of places in the PFPE.That is, the PFPE represented by the formula may be a block copolymer or a random copolymer. Specifically, the perfluoropolyether preferably has at least one structure selected from the group consisting of the following formulas (2) to (5).

[0037] [ka] (In formula (2), n is a positive number, and n is a number in the range that makes the viscosity of PFPE at a temperature of 40°C range from 30 mPa·s to 400 mPa·s.)

[0038] [ka] (In formula (3), n' is a positive number, and n' is a number within the range of 10 mPa·s to 400 mPa·s for the viscosity of PFPE at a temperature of 40°C.)

[0039] [ka] (In formula (4), n'' and m are each independently a positive number, m / n'' is a number that is 0.5 or greater and 2 or less, and n''+m is a number that causes the viscosity of the PFPE at a temperature of 40°C to be in the range of 20 mPa s to 400 mPa s.)

[0040] [ka] (In formula (5), n''' and m' are each independently a positive number, m' / n''' is a number that is 20 or greater and 1000 or less, and n'''+m' is a number that causes the viscosity of the PFPE at a temperature of 40°C to fall within the range of 20 mPa s to 400 mPa s.)

[0041] The viscosity of the PFPE at a temperature of 40°C is preferably 10 mPa·s to 400 mPa·s, more preferably 30 mPa·s to 350 mPa·s, in consideration of good impregnation into the resin tube. The viscosity here is measured at a temperature of 40°C and a shear rate of 100 s using a dynamic viscoelasticity measuring device (rheometer) with a cone-plate type having a cone angle of 1° and a cone radius of 20 mm. -1 The value is measured when the sample is rotated at 100° C. for 60 seconds. An example of the rheometer is the "DHR-2" (trade name, manufactured by TA Instruments). Examples of commercially available PFPEs in the above-mentioned preferred viscosity range include PFPEs having a structure represented by formula (2) (e.g., Demnum S-200, Demnum S-65 (both trade names); manufactured by Daikin Industries, Ltd.), PFPEs having a structure represented by formula (3) (e.g., Krytox GPL-105, Krytox GPL-104, Krytox GPL-103, Krytox GPL-102, Krytox GPL-101 (both trade names); manufactured by Chemours), PFPEs having a structure represented by formula (4) (e.g., Fomblin M07, Fomblin M15 (both trade names); manufactured by Solvay Specialty Polymers), and PFPEs represented by formula (5) (e.g., Fomblin Y15, Fomblin Y25 (both trade names); manufactured by Solvay Specialty Polymers). For example, "Demnum S-200" has a viscosity of 377 mPa·s, "Krytox GPL-105" has a viscosity of 301 mPa·s, "Krytox GPL-104" has a viscosity of 111 mPa·s, "Krytox GPL-103" has a viscosity of 54 mPa·s, "Krytox GPL-102" has a viscosity of 26 mPa·s, and "Krytox GPL-101" has a viscosity of 12 mPa·s. All viscosities are measured at a temperature of 40°C.

[0042] 2. Fixing device The fixing device includes the pressure rotating member described above as the pressure rotating member, a fixing belt, and a heating means for the fixing belt. FIG. 4 is a schematic cross-sectional view of an example of the schematic configuration of a fixing device of a belt heating type. The fixing belt 11 is loosely fitted onto the belt guide member 16. A pressure rigid stay 18 is inserted into the inside of the belt guide member 16. The belt guide member 16 is made of, for example, a resin having heat resistance and heat insulation properties.

[0043] The heating means is, for example, a heater arranged in contact with the inner circumferential surface of the fixing belt. A ceramic heater 17 is provided as a heat source at the position where the belt guide member 16 and the inner surface of the fixing belt 11 come into contact. The ceramic heater 17 is fitted into and fixed in a groove provided along the longitudinal direction of the belt guide member 16. The ceramic heater 17 generates heat when electricity is applied by means not shown. The roller-shaped pressure rotating body 19 is the pressure rotating body described above. It is located between both ends of the pressure rigid stay 18 and a spring receiving member (not shown) on the device chassis side. A pressing spring (not shown) is compressed to apply a downward force to the pressing rigid stay 18. As a result, the lower surface of the ceramic heater 17 disposed on the lower surface of the belt guide member 16 and the upper surface of the pressing rotor 19 are brought into pressure contact with each other across the fixing belt 11, forming a predetermined fixing nip N. In other words, the lower surface of the ceramic heater 17 is disposed in contact with the inner peripheral surface of the fixing belt 11. A recording medium P, which is a heated object and on which an image is formed with unfixed toner G, is sandwiched and conveyed through this fixing nip N at a conveying speed V. This heats and pressurizes the toner image. As a result, the toner image melts and mixes colors, and is then cooled to fix the toner image on the recording medium P. Here, similar effects can be obtained by using a configuration including the pressure rotating body described above in a system other than the belt heating system as in this example, such as a heat roller system.

[0044] 3. Image forming equipment The image forming apparatus may have a known configuration, such as an electrophotographic multifunction machine, copier, fax machine, printer, etc. Here, a color laser printer will be used as an example to provide an outline of the overall configuration of the image forming apparatus. Figure 5 is a schematic cross-sectional view of a laser printer 40. The laser printer 40 shown in Figure 5 has an image forming unit having electrophotographic photosensitive drums 39 (hereinafter referred to as "photosensitive drums 39") that rotate at a constant speed for each of the colors yellow (Y), magenta (M), cyan (C), and black (K). The printer also has an intermediate transfer member 38 that holds the color image developed and multiple-transferred in the image forming unit and further transfers it to a recording medium P fed from a feed unit.

[0045] The photosensitive drums 39 (39Y, 39M, 39C, 39K) are driven to rotate counterclockwise as shown in FIG. 5 by a driving means (not shown). Around the photosensitive drum 39, in the direction of rotation, there are arranged, in this order, charging devices 21 (21Y, 21M, 21C, 21K) that uniformly charge the surface of the photosensitive drum 39, scanner units 22 (22Y, 22M, 22C, 22K) that irradiate a laser beam based on image information and form an electrostatic latent image on the photosensitive drum 39, developing units 23 (23Y, 23M, 23C, 23K) that attach toner to the electrostatic latent image and develop it as a toner image, primary transfer rollers 24 (24Y, 24M, 24C, 24K) that transfer the toner image on the photosensitive drum 39 to the intermediate transfer body 38 at the primary transfer portion T1, and cleaning units 25 (25Y, 25M, 25C, 25K) that have cleaning blades that remove residual toner remaining on the surface of the photosensitive drum 39 after transfer.

[0046] During image formation, a belt-like intermediate transfer body 38 stretched over rollers 26, 27, and 28 rotates, and the toner images of each color formed on each photosensitive drum 39 are superimposed and transferred onto the intermediate transfer body 38 as a primary transfer, thereby forming a color image. The recording medium P is conveyed to the secondary transfer portion T2 by a conveying means so as to be synchronized with the primary transfer onto the intermediate transfer body 38. The conveying means has a feeding cassette 29 storing a plurality of recording media P, a feeding roller 30, a separation pad 31, and a pair of registration rollers 32. During image formation, the feeding roller 30 is driven to rotate in accordance with the image forming operation, separating the recording media P in the feeding cassette 29 one by one, and conveying the recording media P to the secondary transfer portion T2 by the pair of registration rollers 32 in synchronization with the image forming operation.

[0047] A movable secondary transfer roller 33 is disposed at the secondary transfer portion T2. ​​The secondary transfer roller 33 is movable in a substantially vertical direction. During image transfer, the secondary transfer roller 33 is pressed against the intermediate transfer body 38 with a predetermined pressure via the recording medium P. At the same time, a bias is applied to the secondary transfer roller 33, and the toner image on the intermediate transfer body 38 is transferred to the recording medium P. Because the intermediate transfer body 38 and the secondary transfer roller 33 are both driven, the recording medium P sandwiched between them is conveyed in the direction of the left arrow shown in FIG. 5 at a predetermined conveying speed V, and is then conveyed by a conveyor belt 34 to the next process, a fixing unit 35. In the fixing unit 35, heat and pressure are applied to fix the transferred toner image onto the recording medium P. The recording medium P is then discharged onto a discharge tray 37 on the top surface of the device by a pair of discharge rollers 36. [Example]

[0048] The present disclosure will be specifically described below using examples. However, the present disclosure is not limited to the following examples. Unless otherwise specified, the number of parts in the examples and comparative examples is based on mass.

[0049] In this example, the pressurizing rotor was manufactured using the following fluororesin and perfluoropolyether. (Fluorine resin) PFA-1: "959HP-Plus" (product name, manufactured by Mitsui Chemours Fluoroproducts, melting point 296°C) PFA-2: "451HP-J" (product name, manufactured by Mitsui Chemours Fluoroproducts, melting point 305°C) (perfluoropolyether) PFPE-1: "Krytox GPL104" (trade name, manufactured by Chemours, viscosity 111 mPa·s (40°C)) PFPE-2: "Krytox GPL105" (trade name, manufactured by Chemours, viscosity 301 mPa·s (40°C)) PFPE-3: "Krytox GPL103" (trade name, manufactured by Chemours, viscosity 54 mPa·s (40°C))

[0050] Example 1 (Preparation of laminate) First, a 23 mm diameter steel substrate with a sandblasted surface was prepared as the base layer. An addition-curing liquid silicone rubber primer (product name: DY35-051 A&B; a mixture of equal parts of "Liquid A" and "Liquid B" manufactured by Toray Down Corning Co., Ltd.) was sprayed onto the outer periphery of this substrate to form an adhesive layer, resulting in a dry film thickness of 3 μm. This was then baked at 150°C for 30 minutes. Next, an addition-curing liquid silicone rubber (product name: DY35-1349SC; manufactured by Toray Dow Corning Co., Ltd.) (volume resistance value: 10 5 50 parts by mass each of Liquid A (base resin) and Liquid B (curing agent) of Ω·cm product was poured into a mold and heated at 150°C for 1 hour to carry out the primary vulcanization, after which the mold was removed and an elastic layer was formed on the outer periphery of the base. Next, an addition-curing silicone rubber adhesive (product name: SE1819CV; a mixture of equal amounts of "liquid A" and "liquid B" manufactured by Toray Dow Corning Co., Ltd.) was applied to a thickness of 5 μm on the outer surface of the elastic layer. Next, a PFA-1 tube extruded to a thickness of 20 μm was placed over the elastic layer, and the surface of the tube was uniformly rubbed to remove excess adhesive from between the elastic layer and the fluororesin tube. The base layer coated with the elastic layer and surface layer was then placed in an electric furnace set to a temperature of 200° C. and heated for 4 hours to harden the adhesive and bond the tube to the elastic layer, thereby obtaining a laminate A1.

[0051] (Production of pressurizing rotor) (Impregnation process) PFPE-1 was placed in a borosilicate glass measuring cylinder. The measuring cylinder was surrounded by a thermal insulator. A covered heating wire was wrapped around it, and the PFPE was heated to a temperature of 310° C. The laminate A1 was attached to a dipping device, and the entire laminate was immersed in the heated PFPE, and the laminate A1 was taken out after 1 minute. The amount of PFPE in the obtained PFA tube impregnated with PFPE was measured by the following method. That is, a laminate sample consisting of an elastic layer and a resin layer was cut out from the laminate. Next, the laminate sample was immersed in a silicone resin solvent (trade name: eSolv 21RS, manufactured by Kaneko Chemical Co., Ltd.) to dissolve the silicone rubber in the elastic layer, thereby removing the elastic layer from the laminate sample and preparing a measurement sample consisting only of the entire thickness of the PFA tube. This measurement sample was measured using a thermogravimetric analyzer (TGA). The PFPE content (mass%) in the PFPE-containing resin layer was calculated under the following measurement conditions. Apparatus: TGA851 (Mettler Toledo) Atmosphere: In air Temperature: 425℃ In the profile of measurement time versus weight loss rate obtained by the thermogravimetric analysis, a linear least-squares approximation equation was determined from the region where the slope was constant and only PFA was decreasing, and the intercept of the linear least-squares approximation equation was taken as the PFA amount (mass%), and the PFPE content (mass%) was calculated as 100 - PFA amount.

[0052] (Vacancy formation process) Thereafter, the laminate A1 was placed in a measuring cylinder containing a separately prepared fluorine solvent having a hydrofluoroether structure (trade name: Novec 7300, manufactured by 3M), and the measuring cylinder was placed in a water bath of an ultrasonic wave applicator (trade name: Bransonic (model 2510J-DTH); manufactured by Emerson Japan Co., Ltd.), and ultrasonic waves were applied for 60 minutes. After treatment, the laminate was removed from the measuring cylinder and left in an environment at a temperature of 25°C for 60 minutes to dry. In this way, the PFPE present on the surface and inside of the surface layer of the laminate A1 was removed, and a pressure rotating body according to this example was obtained. The pressure rotating body had a white appearance when visually inspected, and it was confirmed that pores had formed in the surface layer.

[0053] Three sets of measurement samples to be used for measuring the following physical properties were prepared as follows. (Preparation of measurement sample) The substrate was separated from the pressure rotor to obtain a laminate B1 consisting of an elastic layer and a surface layer. Next, the laminate B1 was immersed in a silicone resin dissolving agent (trade name: eSolv 21RS, manufactured by Kaneko Chemical Co., Ltd.) to dissolve the silicone rubber in the elastic layer, removing the elastic layer from the laminate B1 and preparing a measurement sample including the entire thickness of the surface layer.

[0054] (Polar orientation in the surface layer (degree of orientation f, orientation angle Φ)) A specimen was cut out from the measurement sample using a sectioning device (for example, a cryo-ultramicrotome (trade name, manufactured by Leica Microsystems) so that the cross section of the surface layer thickness-longitudinal direction of the pressurizing rotor appeared on the surface. The cross section was then observed with a scanning electron microscope, and an image (SEM image) of a rectangular observation area measuring 8 μm in length and 11 μm in width was obtained at a predetermined position on the cross section. At this time, the image was adjusted so that the vertical direction was parallel to the thickness direction of the surface layer and the horizontal direction was parallel to the longitudinal direction of the pressurizing rotor. The SEM image from the cross section was obtained as follows. The images were acquired from three locations. In other words, in the fixing device, the upper end of the observation area was 1 μm in the depth direction from the outer surface of the surface layer that forms the outer surface of the pressure rotor that constitutes the contact surface with the heating rotor, the lower end of the observation area was 1 μm from the surface opposite the outer surface of the surface layer (the surface facing the base layer) toward the outer surface, and the center of the surface layer in the thickness direction was aligned with the center of the observation area. In addition, when the thickness of the surface layer was less than 26 μm, the acquisition positions were adjusted so that the observation areas did not overlap each other. Each of the obtained SEM images was analyzed using numerical calculation software (product name: MATLAB (registered trademark) ); manufactured by MathWorks) was used to perform binarization processing to distinguish the two regions corresponding to the resin portion and the pore portion. The Otsu method was used for the binarization processing. The binary image obtained by the binarization processing was subjected to two-dimensional Fourier transform analysis using the above-mentioned numerical calculation software, and the power spectrum was integrated for each direction to obtain a plot showing the direction and degree of pore orientation. The orientation degree and orientation angle were then calculated from the plot, and their arithmetic mean values ​​were defined as the orientation degree f and orientation degree Φ.

[0055] (Vacancy rate in the surface layer) Furthermore, the pore area ratio was calculated from the ratio of the number of pixels in the area corresponding to pores to the total number of pixels in the observation area from the binarized image.

[0056] (Evaluation 1: Thermal conductivity in the thickness direction of the surface layer) The thermal conductivity λ of the surface layer in the thickness direction was calculated from the following formula. λ=α×Cp ×ρ In the formula, λ is the thermal conductivity of the surface layer in the thickness direction (W / (m K)), and α is the thermal diffusivity in the thickness direction (m 2 / s), C p is the specific heat at constant pressure (J / (kg·K)), and ρ is the density (kg / m 3 ) where the thermal diffusivity in the thickness direction is α, the specific heat at constant pressure is C p The values ​​of ρ and density ρ were determined by the following method.

[0057] (thermal diffusivity α) The thermal diffusivity α in the thickness direction of the surface layer was measured as follows. Sample pieces with an area of ​​8 mm × 12 mm were cut out from the above measurement sample with a cutter to prepare a total of five sample pieces. The thickness of each sample piece was measured using a digital length measuring device (product name: DIGIMICRO MF-501, flat probe φ4 mm, manufactured by Nikon Corporation). Next, each sample piece was measured five times at room temperature (25°C) using a cyclic heating method thermal property measuring device (product name: FTC-1, manufactured by Advance Riko Co., Ltd.), and the average value (m 2 The measurement was carried out while applying pressure to the sample piece using a 1 kg weight. As a result, the thermal diffusivity α of the surface layer in the thickness direction was 4.66×10 -8 m 2 / s.

[0058] (Constant pressure specific heat C p ) Constant pressure specific heat of the surface layer C p was measured using a differential scanning calorimeter (trade name: DSC823e, manufactured by Mettler-Toledo). Specifically, aluminum pans were used as the sample pan and the reference pan, and a blank measurement was performed using a program in which both pans were empty and kept at a constant temperature of 15°C for 10 minutes, then heated to 215°C at a rate of 10°C / min, and then kept at 215°C for another 10 minutes. Next, 10 mg of synthetic sapphire with a known specific heat at constant pressure was used as a reference material, and measurements were performed using the same program. Next, a 10 mg measurement sample of the same weight as the reference synthetic sapphire was cut out from the above measurement sample, placed in a sample pan, and measured using the same program. These measurement results were analyzed using the specific heat analysis software attached to the differential scanning calorimeter, and the constant pressure specific heat at 25°C, C p was calculated. As a result, the constant pressure specific heat of the surface layer C p was 1002.80J / (kg·K).

[0059] (density ρ) The density ρ of the surface layer was measured using a dry automatic densitometer (trade name: Accupyc 1330-01, manufactured by Shimadzu Corporation). Specifically, 10 cm 3 A sample piece was cut out from the measurement sample so as to fill approximately 80% of the cell volume, and after measuring the mass of this sample piece, it was placed in the sample cell. This sample cell was set in the measurement section of the device, and helium was used as the measurement gas. After gas replacement, the volume was measured 10 times. The density of the surface layer was calculated from the mass of the sample piece and the measured volume for each measurement, and the average value was calculated. As a result, the density ρ of the surface layer is 1287.47 kg / m 3 It was.

[0060] Unit-converted specific heat at constant pressure of the surface layer C p (J / (kg·K)) and density ρ(kg / m 3 ), and the measured thermal diffusivity α(m 2 / s), the thermal conductivity λ in the thickness direction of the surface layer was calculated to be 6.01 × 10 -2 W / (m·K).

[0061] (Evaluation 2: Measurement of tensile yield stress of the surface layer) The above measurement sample was cut into a width of 5 mm and a length of 20 mm to prepare a test piece for the tensile test. The test piece was set in the tensile measurement jig of a dynamic viscoelasticity measuring device (product name: Reogel-E4000, manufactured by UBM) with a chuck distance of 10 mm. A torque driver was used to secure the test piece to the jig, with a tightening torque of 5 cN m. The tensile test was performed at a temperature of 200°C and a tensile speed of 0.055 m / s, and the SS curve was measured until the test piece broke. Only data from when the test piece broke between the chucks was used, and the measurement results were taken as the average of five measurements. An approximation line was drawn as a straight line from the 0% to 3% strain portion of the SS curve, and the stress value at the intersection of this approximation curve and a straight line shifted in the positive direction by 5% strain was used as the tensile yield stress.

[0062] (Evaluation 3: Startup time evaluation) The manufactured pressure rotor was mounted in the fixing device shown in Fig. 4, with the pressure applied between the fixing member and the pressure rotor set to 20 kgf. Power was started to be supplied to ceramic heater 17 of the fixing device at 1200 W, and the time until the surface temperature of the fixing member reached 200°C, the temperature at which the fixing device can be fixed, was measured and taken as the start-up time.

[0063] (Rating 4: Durability rating) The following durability test was conducted to evaluate the wear resistance of the surface layer of the pressure rotor. First, the fabricated pressure rotor was mounted in a fixing device having the configuration shown in FIG. 4. This fixing device was incorporated into a laser beam printer capable of high-speed fixing at 60 sheets per minute (process speed 350 mm / sec), and 5,000 sheets of A4-sized paper were continuously fed in continuous paper feed mode. The surface temperature of the fixing belt during fixing was set to 200°C, and the paper was fed in an environment with a temperature of 15°C and a humidity of 20%. Then, after continuous paper feed, the pressure rotor was removed, and the surface of the pressure rotor was visually observed and evaluated according to the following criteria. Rank "A": No cracks are observed on the surface layer. Rank "B": Cracks are observed on the surface layer.

[0064] Examples 2 to 12 Pressurizing rotors 2 to 12 for each experimental example were prepared in the same manner as in Example 1, except that the PFA resin and film thickness of the fluororesin tube used in the surface layer, the type of PFPE to be impregnated, and the PFPE temperature during contact were changed as shown in Table 1.

[0065] Example 13 In the method described in Example 1, an iron substrate laminated with PFA resin (PFA-1) was annealed at 330°C for 30 minutes to obtain a laminate. Thereafter, an impregnation step and a pore formation step were carried out in the same manner as in Example 1 to produce a pressurizing rotor, which was used as the pressurizing rotor 13 according to this example.

[0066] (Comparative Example 1) In the method described in Example 1, the pressure rotor is placed up to the point where the PFA resin is laminated. This was used as the pressurizing rotor C-1 according to this comparative example.

[0067] (Comparative Examples 2 to 4) In the method described in Comparative Example 1, the pressure rotating bodies C-2 to C-4 according to each comparative example were produced in the same manner as in Comparative Example 1, except that the thickness of the PFA resin to be laminated was changed as shown in Table 1.

[0068] (Comparative Example 5) A paint was prepared by mixing 100 parts of a water-based paint containing perfluoroethylene propylene copolymer (product name: EJ-CL500; manufactured by Mitsui-Chemours Fluoroproducts) with 65 parts of microhollow spherical particles (product name: Glass Bubbles iM30K; manufactured by 3M). In addition, an elastic layer and an adhesive layer were formed on an iron substrate in the same manner as in Example 1. Next, the paint prepared above was sprayed onto the surface of the adhesive layer so that the film thickness after baking would be 20 μm. Thereafter, it was baked at a temperature of 340° C. for 30 minutes to produce a pressure rotor C-5 according to this comparative example.

[0069] The formulations and pore properties (pore ratio, orientation degree, f, orientation angle Φ) of the pressure rotors produced in Examples 1 to 13 and Comparative Examples 1 to 5 are shown in Table 1. Note that the pressure rotors C-1 to C-4 according to Comparative Examples 1 to 4 did not have pores in the surface layer, and therefore the pore properties were not measured.

[0070] [Table 1] In Table 1, "pore ratio" indicates the area ratio (%) of pores in the surface layer.

[0071] Table 2 shows the results of evaluations 1 to 4 of the pressurizing rotors produced in Examples 1 to 13 and Comparative Examples 1 to 5.

[0072] [Table 2]

[0073] From Table 2, it was found that the pressurizing rotor of the example exhibited excellent thermal conductivity and did not develop cracks even after long-term use. As a result, it was found that the pressurizing rotor of the example can shorten the start-up time while maintaining durability. [Explanation of symbols]

[0074] Resin part: 201, void: 202

Claims

1. A pressurizing rotor having a base layer, an elastic layer, and a surface layer in this order, the surface layer has pores, The thickness of the surface layer is measured in an area of ​​8 μm in length and 11 μm in width in a cross section perpendicular to the circumferential direction of the pressure rotating body. The average orientation degree f of the pores is 0.20 or more, The orientation angle Φ, which is the average value of the orientation angles, is the angle formed by the longest diameter of the holes with respect to the direction perpendicular to the circumferential direction of the pressurizing rotor, and is 0° or more and 10° or less. A pressurizing rotor characterized by:

2. 2. The pressurizing rotor according to claim 1, wherein the pores occupy an area ratio of 15% to 50% of the area of ​​the region.

3. 3. The pressurizing rotor according to claim 1, wherein the surface layer has a thickness of 12 μm or more and 100 μm or less.

4. 4. The pressurizing rotor according to claim 1, wherein the surface layer contains a fluororesin.

5. 5. The pressurizing rotor according to claim 1, wherein the surface layer contains a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether.

6. 6. The pressurizing rotor according to claim 5, wherein the melting point of the copolymer is 280°C to 320°C.

7. 7. The pressurizing rotor according to claim 1, wherein the pressurizing rotor has an endless belt shape.

8. The pressure rotating body according to any one of claims 1 to 6, wherein the pressure rotating body has a roller shape.

9. The pressure rotating body, the fixing belt, and the fixing belt according to any one of claims 1 to 8 A fixing device including a heating means.

10. An electrophotographic image forming apparatus comprising the fixing device according to claim 9.

11. A method for manufacturing a pressurizing rotor according to any one of claims 1 to 8, comprising: (i) preparing a resin tube manufactured by cylindrical extrusion molding; (ii) a step of obtaining a laminate of a substrate having an endless belt shape or a roller shape, an elastic layer covering the outer peripheral surface of the substrate, and the resin tube covering the outer peripheral surface of the elastic layer; (iii) immersing the laminate in perfluoropolyether to impregnate the resin tube with the perfluoropolyether; and (iv) a step of removing the perfluoropolyether impregnated in the resin tube of the laminate obtained in the step (iii) from the resin tube using a solvent to form pores in the resin tube, thereby forming the surface layer; A method for manufacturing a pressurizing rotor, comprising:

12. The method for producing a pressurizing rotor according to claim 11, wherein the viscosity of the perfluoropolyether at a temperature of 40° C. is 10 mPa·s to 400 mPa·s.

13. 13. The method for manufacturing a pressurizing rotor according to claim 11, wherein the resin tube has a thickness of 12 μm to 100 μm.

14. The method for manufacturing a pressurizing rotor according to any one of claims 11 to 13, wherein the step (iii) includes a step of contacting perfluoropolyether with the outer surface of the resin tube, and the temperature of the perfluoropolyether is Tm±50°C, where Tm (°C) is the melting point of the resin tube.

15. 15. The method for manufacturing a pressurizing rotor according to claim 11, wherein in the step (iii), the resin tube is impregnated with the perfluoropolyether so that the amount of the perfluoropolyether impregnated into the resin tube is 25% by mass to 60% by mass, based on the mass of the resin tube after impregnation with the perfluoropolyether.

16. The method for manufacturing a pressurizing rotor according to any one of claims 11 to 15, wherein the resin tube contains a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether.

17. 17. The method for producing a pressurizing rotor according to claim 16, wherein the step (iii) includes a step of contacting the outer surface of the resin tube with perfluoropolyether, and the temperature of the perfluoropolyether is 250°C to 350°C.

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