Tubes for image forming devices

Abstract

To provide a tube for an image forming apparatus in which a large temperature difference between the center and the ends is effectively suppressed even when the tube is heated to a high temperature due to use in continuous printing, for example. The tube for an image forming apparatus of the present invention comprises: Axial thermal diffusivity A is 3.5×10 -7 m 2 / s or more, Thermal diffusivity B in the thickness direction is 3.5×10 -7 m 2 / s or less, The value obtained by subtracting the thermal diffusivity B from the thermal diffusivity A is 3.0 × 10 -7 That's all.

Description

[Technical Field]

[0001] The present invention relates to a tube for an image forming apparatus, specifically to a tube for an image forming apparatus that constitutes a surface layer of a fixing member (e.g., fixing belt, fixing roll, pressure belt, pressure roll, etc.) used in an electrophotographic image forming apparatus such as a digital printer, a copier, a laser beam printer, or a facsimile, and to a fixing member that has the tube as its surface layer. [Background technology]

[0002] In an electrophotographic image forming apparatus, an electrostatic latent image formed on an image carrier is first developed with toner. Next, the developed toner image is primarily transferred onto an intermediate transfer belt, which is then secondarily transferred onto a recording medium such as paper. Furthermore, the unfixed toner image on the recording medium is heated and pressurized using a fixing member to fix the image to the recording medium.

[0003] In an image forming apparatus, for example, a pressure roller is positioned opposite a fixing belt, a heating roller, and a fixing roller, and a medium such as paper carrying toner passes between the pressure roller and the fixing belt, and is heated at that time, causing the toner to be fixed to the medium. When outputting an image, the pressure roller and the fixing belt are designed to have a size corresponding to the width that can accommodate the largest size of medium, but there is a wide range of medium sizes, and images are sometimes output on narrower media.

[0004] For example, when outputting an image onto a narrow medium, the temperature drops in the area of ​​the pressure roller where the medium passes because heat energy is absorbed to fix the toner. On the other hand, in the area of ​​the pressure roller where the medium does not pass (non-paper passing area), heat energy is not absorbed and accumulates, causing the temperature to rise, resulting in a large temperature difference between the center and end of the pressure roller.

[0005] In particular, when printing continuously, the temperature difference becomes significant, and the non-paper passing area of ​​the pressure roller approaches a temperature exceeding its heat resistance temperature, making it necessary to adjust the printing speed or wait until the temperature drops (see Patent Document 1). This problem is not limited to pressure rollers, but also occurs in fixing belts, fixing rolls, and pressure belts. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 6136636 Summary of the Invention [Problem to be solved by the invention]

[0007] As mentioned above, the fixing members used in image forming devices have the problem that a large temperature difference occurs between the center and ends of the fixing member. In particular, when the image forming device is used continuously, the fixing member continuously becomes hot, and if the temperature difference between the center and ends becomes very large, the temperature at the ends may exceed the heat resistance temperature of the fixing member, which may lead to poor printing, etc.

[0008] In order to solve such problems, attempts have been made to provide a heat-equalizing roller on the pressure roller, or to disperse a highly thermally conductive filler in the elastic layer of the pressure roller, as in Patent Document 1.

[0009] However, providing a heat-equalizing roll increases the number of parts and costs, making it difficult to adopt as a solution.

[0010] Furthermore, dispersing a thermally conductive filler in the elastic layer of the pressure roller is not a sufficient solution. That is, the outer surface of the pressure roller is often made of fluororesin, but because fluororesin has low thermal conductivity, even if the thermal conductivity of the elastic layer is improved, the effect cannot be fully achieved.

[0011] Under these circumstances, the present invention aims to provide a tube for an image forming apparatus that effectively prevents a large temperature difference from occurring between the center and the ends even when the tube becomes hot due to, for example, continuous printing, etc. Another object of the present invention is to provide a fixing member that has the tube for an image forming apparatus as a surface layer. [Means for solving the problem]

[0012] The present inventors have conducted extensive research to solve the above-mentioned problems of the prior art. As a result, they have found that the thermal diffusivity A in the axial direction is 3.5 × 10 -7 m 2 / s or more, and the thermal diffusivity B in the thickness direction is 3.5×10 -7 m 2 / s or less, and the value obtained by subtracting the thermal diffusivity B from the thermal diffusivity A is equal to or greater than a predetermined value, the occurrence of a large temperature difference between the center and the ends is effectively suppressed even when the tube is heated to a high temperature, for example, when used in continuous printing. The present invention was completed based on this finding and through further investigation.

[0013] That is, the present invention provides the following aspects of the invention. Item 1. A tube for an image forming device, Axial thermal diffusivity A is 3.5×10 -7 m 2 / s or more, Thermal diffusivity B in the thickness direction is 3.5×10 -7 m 2 / s or less, The value obtained by subtracting the thermal diffusivity B from the thermal diffusivity A is 3.0 × 10 -7 This completes the tube for an image forming apparatus. Item 2. The tube for an image-forming device according to Item 1, which contains a thermally conductive filler. Item 3. A tube for an image-forming apparatus according to Item 1 or 2, wherein the first layer constituting the outer surface is a single layer. Item 4. The tube for an image-forming apparatus according to Item 1 or 2, which is composed of multiple layers having at least a first layer constituting the outer surface and a second layer located inside the first layer. Item 5. The tube for an image-forming apparatus according to Item 4, wherein the second layer contains a thermally conductive filler. Item 6. The tube for an image-forming apparatus according to Item 4 or 5, wherein the second layer has a thickness greater than the thickness of the first layer. Item 7. A fixing belt made of a laminate including at least a base layer and a surface layer, 7. A fixing belt, wherein the surface layer is formed from the tube for an image-forming apparatus according to any one of items 1 to 6. Item 8. A fixing roll including at least a core metal, an elastic layer covering the core metal, and a surface layer formed on the elastic layer, Item 7. A fixing roll, wherein the surface layer is formed from the tube for an image-forming apparatus according to any one of items 1 to 6. Item 9. A pressure belt made of a laminate including at least a base layer and a surface layer, Item 7. A pressure belt, wherein the surface layer is formed of the tube for an image-forming apparatus according to any one of items 1 to 6. Item 10. A pressure roll comprising at least a core metal, an elastic layer covering the core metal, and a surface layer formed on the elastic layer, Item 7. A pressure roll, the surface layer of which is formed from the tube for an image-forming apparatus according to any one of items 1 to 6. Item 11. Use of a tube in an image forming device, The tube Axial thermal diffusivity A is 3.5×10 -7 m 2 / s or more, Thermal diffusivity B in the thickness direction is 3.5×10 -7 m 2 / s or less, The value obtained by subtracting the thermal diffusivity B from the thermal diffusivity A is 3.0 × 10 -7 That's all. Use of tubing in imaging equipment. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide a tube for an image forming device, which effectively prevents a large temperature difference from occurring between the center and the ends, even when the tube becomes hot, for example, when used in continuous printing, and a fixing member which has the tube as a surface layer. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a schematic cross-sectional view in the radial direction of an example of a tube (single layer) for an image-forming apparatus of the present invention. [Figure 2] 1 is a schematic cross-sectional view in the radial direction of an example of a tube (multi-layer) for an image-forming apparatus of the present invention. [Figure 3] FIG. 2 is a schematic cross-sectional view in the radial direction of an example of a fixing belt or a pressure belt using the image-forming apparatus tube (single layer) shown in FIG. [Figure 4] FIG. 2 is a schematic cross-sectional view in the radial direction of an example of a fixing roll or a pressure roll using the tube (single layer) for an image-forming apparatus shown in FIG. [Figure 5] FIG. 3 is a schematic cross-sectional view in the radial direction of an example of a fixing belt or a pressure belt using the (multi-layer) tube for an image-forming apparatus shown in FIG. 2. [Figure 6] FIG. 3 is a schematic cross-sectional view in the radial direction of an example of a fixing roll or a pressure roll using the (multi-layer) tube for an image-forming apparatus shown in FIG. 2. [Figure 7] 1 is a schematic perspective view of an example of a tube for an image-forming apparatus according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0016] The tube for an image-forming apparatus of the present invention has a thermal diffusivity A in the axial direction of 3.5×10 -7 m 2 / s or more, and the thermal diffusivity B in the thickness direction is 3.5×10 -7 m 2 / s or less, and the value obtained by subtracting the thermal diffusivity B from the thermal diffusivity A (thermal diffusivity A - thermal diffusivity B) is 3.0 x 10 -7 The tube for an image forming apparatus of the present invention is characterized by the above-mentioned configuration, and therefore effectively prevents a large temperature difference from occurring between the center and the ends, even when the tube becomes hot due to, for example, continuous printing.

[0017] Hereinafter, the tube for an image-forming apparatus of the present invention and a fixing member (for example, a fixing belt, a fixing roll, a pressure belt, a pressure roll, etc.) having the tube as a surface layer will be described in detail with reference to FIGS.

[0018] In this specification, numerical values ​​connected with "~" mean a numerical range that includes the numerical values ​​before and after "~" as the lower and upper limits. When multiple lower limits and multiple upper limits are listed separately, any lower limit and upper limit can be selected and connected with "~".

[0019] 1. Tubes for image forming equipment The tube for an image-forming apparatus of the present invention is a tube containing a thermally conductive fluororesin. Specifically, the tube for an image-forming apparatus of the present invention has a layer formed of a thermally conductive fluororesin.

[0020] 1 and 2, the tube for an image-forming apparatus of the present invention has at least a first layer 1 constituting the outer surface. As shown in Fig. 1, the tube for an image-forming apparatus 10 of the present invention may be composed of a single layer of the first layer 1. When the tube for an image-forming apparatus 10 is composed of a single layer of the first layer 1, the first layer 1 is a layer formed from a thermally conductive fluororesin.

[0021] 2, the image-forming apparatus tube 10 of the present invention may be configured with multiple layers, including at least a first layer 1 constituting the outer surface and a second layer 2 located inside the first layer 1. When the image-forming apparatus tube 10 of the present invention is configured with multiple layers, it may be configured with two layers, the first layer 1 and the second layer 2, or, although not shown, another layer may be formed inside the second layer 2 or between the first layer 1 and the second layer 2. At least one of the first layer 1 and the second layer 2 may be a layer formed from a thermally conductive fluororesin, and preferably the second layer 2 is a layer formed from a thermally conductive fluororesin.

[0022] The tube 10 for an image-forming apparatus of the present invention preferably has a cylindrical shape. The length of the tube 10 for an image-forming apparatus of the present invention in the axial direction z may be set appropriately depending on the size of the image-forming apparatus, for example, about 20 to 120 cm. The length of the tube 10 for an image-forming apparatus in the circumferential direction P may be set appropriately depending on the size of the image-forming apparatus, for example, about 25 to 1000 mm.

[0023] The tube 10 for an image-forming apparatus of the present invention has a thermal diffusivity A in the axial direction z of 3.5×10 -7 m 2 / s or more, and the thermal diffusivity B in the thickness direction is 3.5×10 -7 m 2 / s or less, and the value obtained by subtracting thermal diffusivity B from thermal diffusivity A is 3.0 × 10 -7 As a result, even when the tube 10 for an image-forming apparatus of the present invention is subjected to high temperatures, for example, when used in continuous printing, the occurrence of a large temperature difference between the center and the ends is effectively suppressed.

[0024] The thermal diffusivity A in the axial direction z is 3.5×10 -7 m 2 / s or more, but from the viewpoint of more effectively reducing the temperature difference, the lower limit is preferably 3.8 × 10 -7 m 2 / s or more, preferably 4.0 × 10 -7 m2 / s or more, and the upper limit is preferably 15.0 × 10 -7 m 2 / s or less, preferably 12.0 × 10 -7 m 2 / s and below.

[0025] The thermal diffusivity B in the thickness direction is 3.5×10 -7 m 2 / s or less, but from the viewpoint of more effectively reducing the temperature difference, the upper limit is preferably 3.0 × 10 -7 m 2 / s or less, preferably 2.5 × 10 -7 m 2 / s or less, and the lower limit is preferably 0.1 × 10 -7 m 2 / s or more, more preferably 0.3 × 10 -7 m 2 / s or more.

[0026] The value obtained by subtracting thermal diffusivity B from thermal diffusivity A (thermal diffusivity A - thermal diffusivity B) is 3.0 x 10 -7 However, from the viewpoint of more effectively reducing the temperature difference, the lower limit is preferably 3.3 × 10 -7 That's it, 3.5 x 10 -7 That's it, 3.8 x 10 -7 That's it, 5.0 x 10 -7 The above are included, and the upper limit is preferably 9.9 × 10 -7 Less than or equal to 9.1 × 10 -7 The following are included:

[0027] The thermal diffusivity A in the axial direction z is measured using an optical AC thermal diffusivity measuring device (for example, LaserPIT manufactured by Advance Riko Co., Ltd.) by attaching a thermocouple to the surface of a fluororesin tube (30 mm long in the axial direction z) with silver paste. Measurements are taken at three locations: both ends and the center. The specific measurement method is the same as that described in the Examples.

[0028] The thermal diffusivity B in the thickness direction is measured at the center of the axial direction of the fluororesin tube using a thermal insulation thermal conductivity measuring device (e.g., iPhase Mobile, a thermal diffusivity, thermal conductivity, and thermal effusivity measuring system using temperature waves). The specific measuring method is the same as that described in the examples.

[0029] The thickness (wall thickness) of the tube 10 for an image-forming apparatus of the present invention is not particularly limited, but is preferably about 10 to 100 μm, and more preferably about 15 to 50 μm.

[0030] (First layer 1) In the tube 10 for an image-forming apparatus of the present invention, the first layer 1 is a layer that forms the outer surface. When the tube 10 for an image-forming apparatus is formed of a single layer, the tube 10 for an image-forming apparatus is formed of the first layer 1, and the first layer 1 is a layer formed of a thermally conductive fluororesin. When the second layer 2 described below is a layer formed of a thermally conductive fluororesin, the first layer 1 may or may not be a layer formed of a thermally conductive fluororesin, but is preferably not a layer formed of a thermally conductive fluororesin.

[0031] The first layer 1 preferably contains a fluorine-based resin. The fluorine-based resin is not particularly limited, but from the viewpoint of more effectively reducing the temperature difference, examples include tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), fluorinated ethylene propylene (FEP), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), tetrafluoroethylene hexafluoropropylene vinylidene fluoride (THV), and tetrafluoroethylene-ethylene copolymer (ETFE). Among these, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) is particularly preferred. The fluorine-based resin may be used alone or in combination of two or more.

[0032] In the first layer 1, the melting point of the fluororesin is not particularly limited, but from the viewpoint of more effectively reducing the temperature difference, the lower limit is preferably 260°C or higher, more preferably 270°C or higher, even more preferably 280°C or higher, and particularly preferably 290°C or higher, and the upper limit is preferably 330°C or lower, more preferably 320°C or lower, even more preferably 310°C or lower, and particularly preferably 300°C or lower. In particular, from the viewpoint of improving durability, the melting point of the fluororesin of the first layer 1 is preferably 310°C or lower. From the viewpoint of achieving both high durability and high suppression of electrostatic offset, the melt mass flow rate (MFR) of the fluororesin at 372°C is preferably about 1 to 20 g / 10 min, more preferably about 1.2 to 6 g / 10 min, and even more preferably about 1.5 to 2.5 g / 10 min.

[0033] Furthermore, when the first layer 1 is a layer formed from a thermally conductive fluororesin, the first layer 1 preferably contains a thermally conductive filler in addition to the fluororesin. In the present invention, the thermally conductive filler is a ceramic material with high insulation properties and high thermal conductivity, and the thermal conductivity is preferably 50 W / m·K or higher, more preferably 55 W / m·K or higher, and even more preferably 60 W / m·K or higher. Examples of thermally conductive fillers include fillers with higher thermal conductivity than carbon black. Specific examples of thermally conductive fillers include boron nitride, graphite, aluminum nitride, alumina, and magnesium oxide. Only one type of thermally conductive filler may be used, or two or more types may be mixed together.

[0034] The particle size of the thermally conductive filler is not particularly limited, but from the viewpoint of more effectively reducing the temperature difference, it is preferably about 1 to 100 μm, more preferably about 5 to 90 μm, and even more preferably about 10 to 80 μm.

[0035] In the tube 10 for an image-forming apparatus of the present invention, the thermally conductive filler contained in the layer formed from the thermally conductive fluororesin is not particularly limited as long as it satisfies the requirements for the thermal diffusivities A and B, but from the viewpoint of more effectively reducing the temperature difference, the lower limit is preferably 5% by mass or more, more preferably 8% by mass or more, and the upper limit is preferably 25% by mass or less, more preferably 22% by mass or less. In the tube 10 for an image-forming apparatus, when the first layer 1 is a layer formed from a thermally conductive fluororesin, it is preferable that the thermally conductive filler contained in the first layer 1 has the above content.

[0036] The first layer 1 may contain other fillers (fillers different from the thermally conductive filler) such as carbon black. The other fillers are not particularly limited, but may include carbon black, silica, mica, zinc oxide, chromium oxide, PTFE, polymeric silicone, etc., from the viewpoint of improving abrasion resistance. The other fillers may be used singly or in combination of two or more.

[0037] When the first layer 1 contains other fillers, the content of the other fillers is not particularly limited, but from the viewpoint of effectively improving abrasion resistance, it is preferably about 0.1 to 10 mass %.

[0038] Furthermore, the first layer 1 may contain, as necessary, at least one of additives commonly used in tubes for image-forming devices, such as antioxidants, heat stabilizers, light stabilizers, lubricants, anti-fogging agents, slip agents, flame retardants, surface conditioners, etc. When these additives are contained, the content of each additive is not particularly limited, but is preferably about 0.1 to 10% by mass each.

[0039] The thickness of the first layer 1 is not particularly limited, but when the tube 10 for an image-forming apparatus is composed of a single layer of the first layer 1, the thickness is preferably about 10 to 100 μm, and more preferably about 15 to 50 μm.

[0040] (Second Layer 2) The second layer 2 is a layer located inside the first layer 1. The second layer 2 may or may not be a layer formed from a thermally conductive fluororesin, but is preferably a layer formed from a thermally conductive fluororesin.

[0041] The second layer 2 preferably contains a fluorine-based resin. The fluorine-based resin is not particularly limited, but from the viewpoint of more effectively reducing the temperature difference, examples include those exemplified for the first layer 1, and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) is particularly preferred. The fluorine-based resin may be used alone or in combination of two or more.

[0042] In the second layer 2, the melting point of the fluororesin is not particularly limited, but from the viewpoint of more effectively reducing the temperature difference, the lower limit is preferably 260° C. or higher, more preferably 270° C. or higher, even more preferably 280° C. or higher, and particularly preferably 290° C. or higher, and the upper limit is preferably 330° C. or lower, more preferably 320° C. or lower, even more preferably 310° C. or lower, and particularly preferably 300° C. or lower. From the same viewpoint, the melt mass flow rate (MFR) of the fluororesin at 372° C. is preferably about 1 to 20 g / 10 min, more preferably about 1.2 to 6 g / 10 min, and even more preferably about 1.5 to 2.5 g / 10 min.

[0043] Furthermore, when the second layer 2 is a layer formed from a thermally conductive fluororesin, the second layer 2 preferably contains a thermally conductive filler in addition to the fluororesin. Specific examples of the thermally conductive filler include ceramic materials with high insulation properties and high thermal conductivity, preferably with a thermal conductivity of 50 W / m·K or higher. Specific examples of the thermally conductive filler include boron nitride, aluminum nitride, alumina, and magnesium oxide. Only one type of thermally conductive filler may be used, or two or more types may be mixed together.

[0044] The particle size of the thermally conductive filler is not particularly limited, but from the viewpoint of more effectively reducing the temperature difference, it is preferably about 1 to 100 μm, more preferably about 5 to 90 μm, and even more preferably about 10 to 80 μm.

[0045] The thermally conductive filler contained in the layer formed of the thermally conductive fluororesin in the tube 10 for an image-forming apparatus of the present invention is as described above. When the second layer 2 in the tube 10 for an image-forming apparatus is a layer formed of the thermally conductive fluororesin, it is preferable that the content of the thermally conductive filler contained in the second layer 2 is as described above.

[0046] The second layer 2 may contain other fillers such as carbon black (fillers different from the thermally conductive filler). Examples of other fillers include, but are not limited to, carbon black, silica, mica, zinc oxide, chromium oxide, PTFE, and polymeric silicone, from the viewpoint of improving abrasion resistance. The other fillers may be used singly or in combination of two or more.

[0047] When the second layer 2 contains other fillers, the content of the other fillers is not particularly limited, but from the viewpoint of effectively improving abrasion resistance, it is preferably about 0.1 to 10 mass %.

[0048] Furthermore, the second layer 2 may contain, as necessary, at least one of additives commonly used in tubes for image-forming devices, such as antioxidants, heat stabilizers, light stabilizers, lubricants, anti-fogging agents, slip agents, flame retardants, surface conditioners, etc. When these additives are contained, the content of each additive is not particularly limited, but is preferably about 0.1 to 10% by mass each.

[0049] The thickness of the second layer 2 is not particularly limited, but from the viewpoint of more effectively reducing the temperature difference, it is preferably about 20 to 150 μm, more preferably about 50 to 100 μm.

[0050] As a method for manufacturing the image-forming apparatus tube 10 of the present invention, a known tube manufacturing method can be applied so as to obtain the configuration of the image-forming apparatus tube 10 of the present invention. For example, when the image-forming apparatus tube 10 is configured with a single first layer that forms the outer surface, one method is to extrude the thermally conductive fluororesin that forms the first layer 1 into a cylindrical shape by melt extrusion molding, and then wind it up flat around a roller while cooling. Melt extrusion molding can be performed, for example, using a twin-screw extruder.

[0051] Furthermore, when the tube 10 for an image-forming apparatus is composed of multiple layers having at least a first layer 1 constituting the outer surface and a second layer 2 located inside the first layer 1, an example of a method is to extrude the resin constituting the first layer 1 and the resin constituting the second layer 2 into a cylindrical shape by melt extrusion molding, and then wind the resin into a flat shape around a roller while cooling. Melt extrusion molding can be performed, for example, using a twin-screw extruder. Another example of a method for forming a tube in a state in which the first layer 1 and the second layer 2 are laminated is to co-extrude the resins constituting each layer using a two-kind, two-layer twin-screw extruder equipped with an annular die.

[0052] The tube 10 for an image-forming apparatus of the present invention can be suitably used as a tube for an image-forming apparatus.

[0053] 2. Fixing member The fixing member of the present invention has the image-forming apparatus tube 10 of the present invention as a surface layer. For example, when the image-forming apparatus tube 10 of the present invention is used for a fixing belt 11 or a pressure belt 12, the fixing belt 11 or the pressure belt 12 can be a laminate including at least a base layer 3 and a surface layer (image-forming apparatus tube 10), as shown in the schematic diagram of Fig. 2. Furthermore, although not shown, the fixing belt 11 or the pressure belt 12 can also be a laminate including at least a base layer 3, an elastic layer 4 described below, and a surface layer (image-forming apparatus tube 10).

[0054] The base layer 3 is not particularly limited and can be made of a resin or metal used in base layers of known fixing members. Examples of resins include polyimide (PI), polyetherimide (PEI), polyamideimide (PAI), polyetherketone (PEK), polyetheretherketone (PEEK), and polyphenylsulfone (PPSU). Examples of metals include nickel.

[0055] The thickness of the base layer 3 is not particularly limited, but is preferably about 50 to 200 μm, and more preferably about 60 to 160 μm.

[0056] Furthermore, when the tube 10 for an image forming apparatus of the present invention is used as a fixing roll 13 or a pressure roll 14, the fixing roll 13 or the pressure roll 14 can be configured to include at least a core 5, an elastic layer 4 covering the core 5, and a surface layer formed on the elastic layer 4 (tube 10 for an image forming apparatus), as shown in Figure 3.

[0057] There are no particular limitations on the metal constituting the core metal 5, and it is possible to use a known metal that is used for the fixing roll 13 or pressure roll 14. Preferred examples of the metal include nickel and stainless steel (SUS).

[0058] Furthermore, the elastic material constituting the elastic layer 4 in the fixing belt 11, pressure belt 12, fixing roll 13, or pressure roll 14 is not particularly limited and may be any elastic material used in known fixing members, preferably silicone rubber. The thickness of the elastic layer 4 is not particularly limited, but is preferably about 3000 to 6000 μm for a fixing roll, and about 100 to 400 μm for a fixing belt.

[0059] The fixing belt 11 or pressure belt 12 having the image-forming device tube 10 of the present invention as a surface layer can be manufactured by a known method of overlapping the outer surface of the base layer 3 on the inner surface of the surface layer (image-forming device tube 10). As described above, the surface layer (image-forming device tube 10) can be manufactured by, for example, melt extrusion molding. Similarly, the base layer 3 can also be manufactured by melt extrusion molding. Furthermore, when overlapping the outer surface of the base layer 3 on the inner surface of the surface layer (image-forming device tube 10), an elastic layer 4 may be disposed between the surface layer (image-forming device tube 10) and the base layer 3.

[0060] In addition, the fixing roll 13 and the pressure roll 14 can each be manufactured by a known method, such as a method of sequentially forming an elastic layer and a surface layer on the outer surface of a cylindrical core metal 5, or a method of inserting the core metal 5 into a laminate of the elastic layer 4 and the surface layer. [Example]

[0061] The present invention will be described in detail below with reference to examples and comparative examples. However, the present invention is not limited to these examples. The raw materials used in the examples and comparative examples are as follows.

[0062] <Fluorine-based resin> Fluorine-based resin A: PFA resin (PFA350J manufactured by Mitsui Dipont Fluorochemicals) Fluorine-based resin B: Carbon black-containing PFA resin (Mitsui Dipont Fluorochemicals, conductive PFA, carbon black content 8% by mass, volume resistance 10 7 Ω / □ or less)

[0063] <Thermal conductive filler> Thermally conductive filler A: Graphite (Imerys Graphite & Carbon Co., Ltd. flake graphite "TIMREX C-THERM"), thermal conductivity 300 W / m K Thermally conductive filler B: Graphite (Imerys Graphite & Carbon Co., Ltd. spherical graphite "TIMREX KS44"), thermal conductivity 300 W / m K Thermally conductive filler C: Boron nitride (Momentive Performance Materials Boron Nitride "PT180"), thermal conductivity 60 W / m K

[0064] Example 1 A mixture was obtained by dry-mixing thermally conductive filler A (content shown in Table 1: 10% by mass) and fluororesin A (PFA resin, 90% by mass). The mixture was then extrusion-molded at 250 to 350°C using a twin-screw kneading extruder to produce thermally conductive filler-containing fluororesin pellets. Next, using a circular die, the obtained thermally conductive filler-containing fluororesin pellets were extruded into a tubular shape at 300 to 420°C using a single-screw extruder to obtain a fluororesin tube (thickness 30 μm, inner diameter 30 mm).

[0065] <Example 2> A mixture was obtained by dry-mixing thermally conductive filler A (content shown in Table 1: 20% by mass) and fluororesin A (PFA resin, 80% by mass). The mixture was then extrusion-molded at 250 to 350°C using a twin-screw kneading extruder to produce thermally conductive filler-containing fluororesin pellets. Next, using a circular die, the obtained thermally conductive filler-containing fluororesin pellets were extrusion-molded into a tubular shape at 300 to 420°C using a single-screw extruder to obtain a fluororesin tube (thickness 30 μm, inner diameter 30 mm).

[0066] Example 3 A mixture was obtained by dry-mixing thermally conductive filler A (content shown in Table 1: 20% by mass) and fluororesin B (carbon black-containing PFA resin, 80% by mass). The mixture was then extrusion-molded using a twin-screw kneading extruder at 250 to 350°C to produce thermally conductive filler-containing fluororesin pellets. Next, using a circular die, the obtained thermally conductive filler-containing fluororesin pellets were extrusion-molded into a tubular shape using a single-screw extruder at 300 to 420°C to obtain a fluororesin tube (thickness 30 μm, inner diameter 30 mm).

[0067] Example 4 A mixture was obtained by dry-mixing thermally conductive filler B (content shown in Table 1: 10% by mass) and fluororesin A (PFA resin, 90% by mass). The mixture was then extrusion-molded using a twin-screw kneading extruder at 250 to 350°C to produce thermally conductive filler-containing fluororesin pellets. Next, using a circular die, the obtained thermally conductive filler-containing fluororesin pellets were extrusion-molded into a tubular shape using a single-screw extruder at 300 to 420°C to obtain a fluororesin tube (thickness 30 μm, inner diameter 30 mm).

[0068] <Example 5> A mixture was obtained by dry-mixing thermally conductive filler C (content shown in Table 1: 10% by mass) and fluororesin A (PFA resin, 90% by mass). The mixture was then extrusion-molded using a twin-screw kneading extruder at 250 to 350°C to produce thermally conductive filler-containing fluororesin pellets. Next, using a circular die, the obtained thermally conductive filler-containing fluororesin pellets were extrusion-molded into a tubular shape using a single-screw extruder at 300 to 420°C to obtain a fluororesin tube (thickness 30 μm, inner diameter 30 mm).

[0069] <Comparative Example 1> Fluorine-based resin A (PFA resin, 100% by mass) was extruded using a twin-screw kneading extruder at 250 to 350°C to produce fluororesin pellets. Next, using a circular die, the obtained fluororesin pellets were extruded into a tubular shape using a single-screw extruder at 300 to 420°C to produce a fluororesin tube (thickness 30 μm, inner diameter 30 mm).

[0070] <Comparative Example 2> A mixture was obtained by dry-mixing thermally conductive filler B (content shown in Table 1: 30% by mass) and fluororesin A (PFA resin, 70% by mass). The mixture obtained was then extrusion-molded at 250 to 350°C using a twin-screw kneading extruder to produce thermally conductive filler-containing fluororesin pellets. Next, using a circular die, the obtained thermally conductive filler-containing fluororesin pellets were extruded into a tubular shape at 300 to 420°C using a single-screw extruder, but a fluororesin tube could not be obtained.

[0071] Example 6 A mixture was obtained by dry-mixing thermally conductive filler A (content shown in Table 1: 10% by mass) and fluororesin A (PFA resin, 90% by mass). The resulting mixture was then extrusion-molded at 250 to 350°C using a twin-screw kneading extruder to produce thermally conductive filler-containing fluororesin pellets. Next, using a two-kind, two-layer extruder equipped with an annular die, tubular extrusion molding was performed at 300 to 420°C by co-extrusion, so that the thermally conductive filler-containing fluororesin formed the second layer (inner layer, 25 μm) and the fluororesin A formed the first layer (surface layer, 5 μm), to obtain a fluororesin tube (thickness 30 μm, inner diameter 30 mm).

[0072] Example 7 A mixture was obtained by dry-mixing thermally conductive filler A (content shown in Table 1: 20% by mass) and fluororesin A (PFA resin, 80% by mass). The resulting mixture was then extrusion-molded at 250 to 350°C using a twin-screw kneading extruder to produce thermally conductive filler-containing fluororesin pellets. Next, using a two-kind, two-layer extruder equipped with an annular die, tubular extrusion molding was performed at 300 to 420°C by co-extrusion, so that the thermally conductive filler-containing fluororesin formed the second layer (inner layer, 25 μm) and the fluororesin A formed the first layer (surface layer, 5 μm), to obtain a fluororesin tube (thickness 30 μm, inner diameter 30 mm).

[0073] Example 8 A mixture was obtained by dry-mixing thermally conductive filler A (content shown in Table 1: 20% by mass) and fluororesin A (PFA resin, 80% by mass). The resulting mixture was then extrusion-molded at 250 to 350°C using a twin-screw kneading extruder to produce thermally conductive filler-containing fluororesin pellets. Next, using a two-kind, two-layer extruder equipped with an annular die, tubular extrusion molding was performed at 300 to 420°C by co-extrusion, so that the thermally conductive filler-containing fluororesin formed the second layer (inner layer, 15 μm) and the fluororesin A formed the first layer (surface layer, 15 μm), to obtain a fluororesin tube (thickness 30 μm, inner diameter 30 mm).

[0074] <Thickness measurement> For the fluororesin tubes obtained in the examples and comparative examples, the thickness of each layer was measured using an Otsuka Electronics multichannel spectrometer MCPD-9800 in accordance with the provisions of JIS Z8724 "Method of measuring color - Light source color" (principle of the device). In the measurement, a Y-shaped fiber combining a light-emitting fiber and a light-receiving fiber was used to direct light perpendicularly to the sample surface, and the light reflected perpendicularly was measured. The measurement conditions were a wavelength range of 900 nm to 1900 nm, an exposure time of 250 ms, and one integration. The results are shown in Table 1.

[0075] <Measurement of axial thermal diffusivity A> Using an AC optical thermal diffusivity measuring device (LaserPIT manufactured by Advance Riko Co., Ltd.), thermocouples were attached with silver paste to the surface of each of the fluororesin tubes (30 m long in the axial direction z) obtained above, and the thermal diffusivity A in the axial direction was measured. Measurements were taken at three locations: both ends and the center. The results are shown in Table 1.

[0076] <Measurement of thermal diffusivity B in the thickness direction> Using an insulation thermal conductivity measuring device (iPhase Mobile, a thermal diffusivity, thermal conductivity, and thermal effusivity measuring system using temperature waves), the thermal diffusivity B in the thickness direction was measured for the central part in the axial direction of each of the fluororesin tubes obtained above. The results are shown in Table 1.

[0077] <Evaluation of temperature difference between center and edge> A fixing pressure roll (see Figure 4) was prepared, which was layered from the inside out with a core metal, silicone rubber, and a fluororesin tube, and a continuous paper feed test (100,000 A4 documents were fed continuously) was conducted. Immediately after the continuous paper feed test, the temperature at the end of the pressure roll was measured, and the improvement in the end temperature (temperature increase suppressed) compared to Comparative Example 1 was evaluated. The results are shown in Table 1.

[0078] [Table 1]

[0079] As shown in Table 1, in Examples 1 to 8, the effect of improving the edge temperature was suitably exhibited, and in Examples 2 to 4 and 7, the effect of improving the edge temperature was particularly large. [Explanation of symbols]

[0080] 1...First layer 1a...Outer surface 2...Second layer 3…Base material layer 4...Elastic layer 5...Core 10...Tube for image forming device 11...Fuser belt 12...Compression belt 13...Fuser roll 14...Pressure roll

Claims

1. Tubes for image forming devices (excluding those containing carbon fiber), the tube for an image forming apparatus is configured by a single first layer that configures an outer surface, the first layer includes a fluorine-based resin and a thermally conductive filler; the fluorine-based resin is a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA); the thermally conductive filler is at least one of boron nitride and graphite; Axial thermal diffusivity A is 4.2 x 10 -7 m 2 / s or more 9.5×10 -7 m 2 / s or less, Thermal diffusivity B in the thickness direction is 0.7 × 10 -7 m 2 / s or more 2.2×10 -7 m 2 / s or less, The value obtained by subtracting the thermal diffusivity B from the thermal diffusivity A is 3.3 × 10 -7 This completes the tube for an image forming apparatus.

2. Tubes for image forming devices (excluding those containing carbon fiber), the tube for an image forming apparatus is configured by a multi-layer structure having at least a first layer constituting an outer surface and a second layer located inside the first layer, the second layer includes a fluorine-based resin and a thermally conductive filler; the fluorine-based resin is a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA); the thermally conductive filler is at least one of boron nitride and graphite; Axial thermal diffusivity A is 4.2 x 10 -7 m 2 / s or more 9.5×10 -7 m 2 / s or less, Thermal diffusivity B in the thickness direction is 0.7 × 10 -7 m 2 / s or more 2.2×10 -7 m 2 / s or less, The value obtained by subtracting the thermal diffusivity B from the thermal diffusivity A is 3.3 × 10 -7 This completes the tube for an image forming apparatus.

3. 3. The tube for an image-forming apparatus according to claim 2, wherein the second layer has a thickness greater than that of the first layer.

4. A fixing belt made of a laminate including at least a base layer and a surface layer, A fixing belt, wherein the surface layer is formed from the tube for an image-forming apparatus according to any one of claims 1 to 3.

5. A fixing roll including at least a core metal, an elastic layer covering the core metal, and a surface layer formed on the elastic layer, A fixing roll, wherein the surface layer is formed from the tube for an image-forming apparatus according to any one of claims 1 to 3.

6. A pressure belt comprising a laminate including at least a base layer and a surface layer, A pressure belt, wherein the surface layer is formed of the tube for an image-forming apparatus according to any one of claims 1 to 3.

7. A pressure roll including at least a core metal, an elastic layer covering the core metal, and a surface layer formed on the elastic layer, A pressure roll, wherein the surface layer is formed from the tube for an image-forming apparatus according to any one of claims 1 to 3.

8. Tubes (excluding those containing carbon fiber ) in an image forming apparatus, The tube is constructed of a single layer of a first layer that forms an outer surface, the first layer includes a fluorine-based resin and a thermally conductive filler; the fluorine-based resin is a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA); the thermally conductive filler is at least one of boron nitride and graphite; Axial thermal diffusivity A is 4.2 x 10 -7 m 2 / s or more 9.5×10 -7 m 2 / s or less, Thermal diffusivity B in the thickness direction is 0.7 × 10 -7 m 2 / s or more 2.2×10 -7 m 2 / s or less, The value obtained by subtracting the thermal diffusivity B from the thermal diffusivity A is 3.3 × 10 -7 That's all. Use of tubing in imaging equipment.

9. Tubes (excluding those containing carbon fiber ) in an image forming apparatus, The tube is configured by a multi-layer structure having at least a first layer constituting an outer surface and a second layer located inside the first layer, the second layer includes a fluorine-based resin and a thermally conductive filler; the fluorine-based resin is a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA); the thermally conductive filler is at least one of boron nitride and graphite; Axial thermal diffusivity A is 4.2 x 10 -7 m 2 / s or more 9.5×10 -7 m 2 / s or less, Thermal diffusivity B in the thickness direction is 0.7 × 10 -7 m 2 / s or more 2.2×10 -7 m 2 / s or less, The value obtained by subtracting the thermal diffusivity B from the thermal diffusivity A is 3.3 × 10 -7 That's all. Use of tubing in imaging equipment.

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