Method for manufacturing a surface coating layer for fixing members, fixing rollers, pressure rollers, and resin tubes for fixing members.

Abstract

To provide a surface coating layer for fixing members that has excellent wear resistance. [Solution] A resin tube for a fixing member, wherein the surface coating layer for the fixing member is made of a resin composition, the resin composition comprises at least one resin selected from the group consisting of polyethylene, polyetheretherketone, polyimide, polyamideimide, polymethylpentene, polyolefin, polyphenylene sulfide, polysulfone, polyetherimide, polyarylate, polyethersulfone, and polyethernitrile, the surface coating layer for the fixing member is irradiated with radiation in a low-oxygen atmosphere at a temperature above its melting point, and the pencil hardness of the outer surface is HB or higher.

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a surface coating layer for a fixing member, a fixing roller, a pressure roller, and a resin tube for a fixing member.

Background Art

[0002] Generally, in an image forming process in a copier, a laser beam printer, etc. that utilize an electrophotographic method, first, a toner image is formed on a transfer material such as recording paper through an exposure process, a developing process, and a transfer process. Thereafter, a fixing process for fixing this unfixed toner image to the transfer material is performed. As a fixing method, a method of heating and pressurizing the unfixed toner image to fuse it onto the transfer material is common. As heating means and pressurizing means, as shown in FIG. 1, a fixing roller 1 and a pressure roller 3 are opposed to each other, and a transfer material 4 on which an unfixed toner image 5 is placed is passed between them, and while pressurizing between both rollers, it is heated by a heating source 2 provided in the fixing roller 1 to form a fixed toner image 6. This method is widely adopted.

[0003] As a material for the surface of such a fixing roller, a fluororesin excellent in abrasion resistance, heat resistance, and releasability with respect to toner is widely used. For example, in Japanese Patent Application Laid-Open No. 2019-151765, a crosslinked fluororesin tube is disclosed that has a crosslinked fluororesin as a main component, the fluororesin is a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer or a tetrafluoroethylene-hexafluoropropylene copolymer, and has a heat shrinkage rate of 30% or more.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Fluoropolymers possess excellent abrasion resistance, non-stick properties, heat resistance, and chemical resistance. Therefore, they are used in a variety of fields, including automotive parts, semiconductor manufacturing equipment, sliding parts in image forming machinery, and wire insulation. However, the EU has proposed the REACH regulation, which aims to restrict the production, distribution, and use of all fluorine-containing compounds (PFAS). Consequently, fluoropolymers may be subject to potential restrictions. Therefore, there is a need for new materials to replace fluoropolymers for the surface (outer surface) of fixing rollers.

[0006] As mentioned above, the surface material of the fuser roller requires abrasion resistance, heat resistance, and toner release properties, but no material is yet known that has toner release properties comparable to fluororesin. Therefore, there is a need to develop a resin tube suitable for methods of physically releasing toner from the fuser roller using blades or the like (for example, Figure 2).

[0007] This disclosure has been made in view of the above circumstances and aims to provide a surface coating layer for fixing members that has excellent wear resistance. [Means for solving the problem]

[0008] The surface coating layer for the fixing member relating to this disclosure is A surface coating layer for a fixing member, The above surface coating layer consists of a resin composition. The above resin composition comprises at least one resin selected from the group consisting of polyethylene, polyetheretherketone, polyimide, polyamideimide, polymethylpentene, polyolefin, polyphenylene sulfide, polysulfone, polyetherimide, polyarylate, polyethersulfone, and polyethernitrile. The surface coating layer for the above-mentioned fixing member is irradiated with radiation in a low-oxygen atmosphere at a temperature above its melting point. The pencil hardness of the above surface coating layer is HB or higher.

[0009] The method for manufacturing a resin tube for a fixing member according to this disclosure is: A step of preparing a resin tube made of a resin composition, The process involves irradiating the outer surface of the above-mentioned resin tube with radiation in a low-oxygen atmosphere at a temperature above its melting point, Includes, The above resin composition comprises at least one resin selected from the group consisting of polyethylene, polyetheretherketone, polyimide, polyamideimide, polymethylpentene, polyolefin, polyphenylene sulfide, polysulfone, polyetherimide, polyarylate, polyethersulfone, and polyethernitrile.

[0010] When coating a substrate with a resin tube for fixing components, an adhesive layer may be used. Examples of adhesive layers include polyamide (PA), polyamide-imide (PAI), and polyethersulfone (PES). These can be used individually, in combination, or blended with carbon, etc. Methods for molding onto a substrate include applying a mixed paint, powder coating, or injection molding. [Effects of the Invention]

[0011] This disclosure makes it possible to provide a surface coating layer for fixing members that has excellent wear resistance. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a schematic diagram illustrating a fixing method using a fixing roller. [Figure 2] Figure 2 is a schematic diagram illustrating the method of physically releasing toner in a fixing system using a fixing roller. [Figure 3] Figure 3 is a schematic cross-sectional view showing a resin tube, which is an example of a surface coating layer for a fixing member according to this embodiment. [Figure 4] Figure 4 is a schematic diagram illustrating a method for coating the inner surface of a cylindrical body. [Figure 5]FIG. 5 is a schematic diagram for explaining a method of irradiating a resin tube with radiation.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] [DESCRIPTION OF EMBODIMENTS OF THE PRESENT DISCLOSURE] First, embodiments of the present disclosure will be listed and described. [1] The surface coating layer for the fixing member according to the present disclosure is a surface coating layer for the fixing member, wherein the surface coating layer is made of a resin composition, the resin composition contains at least one resin selected from the group consisting of polyethylene, polyether ether ketone, polyimide, polyamideimide, polymethylpentene, polyolefin, polyphenylene sulfide, polysulfone, polyetherimide, polyarylate, polyether sulfone, and polyether nitrile, the surface coating layer for the fixing member is irradiated with radiation in a low oxygen atmosphere at a temperature equal to or higher than the melting point, and the pencil hardness of the surface coating layer is HB or higher.

[0014] The surface coating layer is irradiated with radiation in a low oxygen atmosphere at a temperature equal to or higher than the melting point, and the pencil hardness of the surface coating layer is improved. That is, by having the above-described configuration, the surface coating layer for the fixing member has excellent wear resistance.

[0015] [2] In the surface coating layer for the fixing member of [1] above, the thermal conductivity of the surface coating layer may be 0.4 W / mk or higher. By doing so, in addition to wear resistance, it becomes possible to provide a surface coating layer for the fixing member having excellent fixing property.

[0016] [3] In the surface coating layer for the fixing member of [1] or [2] above, The microhardness of the surface coating layer described above may be 50° or higher. This makes it possible to provide a surface coating layer for fixing members that has excellent adhesion properties in addition to wear resistance.

[0017] [4] In the surface coating layer for any of the fixing members described in [1] to [3] above, The thickness of the above surface coating layer may be 1 μm or more and 500 μm or less. By doing so, it becomes possible to provide a surface coating layer for fixing members that has excellent adhesion in addition to abrasion resistance.

[0018] [5] The fixing roller relating to this disclosure is The fixing member is provided with one of the surface coating layers described in [1] to [4] above. This makes it possible to provide a fixing roller with excellent wear resistance.

[0019] [6] The pressure roller according to this disclosure is provided with a surface coating layer for any of the fixing members described in [1] to [4] above. This makes it possible to provide a pressure roller with excellent wear resistance.

[0020] [7] The method for manufacturing a resin tube for fixing member according to the present disclosure is: A step of preparing a resin tube made of a resin composition, The process involves irradiating the outer surface of the above-mentioned resin tube with radiation in a low-oxygen atmosphere at a temperature above its melting point, Includes, The above resin composition comprises at least one resin selected from the group consisting of polyethylene, polyetheretherketone, polyimide, polyamideimide, polymethylpentene, polyolefin, polyphenylene sulfide, polysulfone, polyetherimide, polyarylate, polyethersulfone, and polyethernitrile.

[0021] The resin tube described above has its outer surface irradiated with radiation at a temperature above its melting point in a low-oxygen atmosphere, thereby improving the pencil hardness of the outer surface. In other words, by having the above-described configuration, the manufacturing method of the resin tube can produce a resin tube for fixing members that has excellent wear resistance.

[0022] [Details of the embodiments of this disclosure] Hereinafter, one embodiment of the present disclosure (hereinafter referred to as "this embodiment") will be described. However, this embodiment is not limited thereto. In this specification, the notation in the form of "A~Z" means the upper and lower limits of a range (i.e., A or greater and Z or less), and if no unit is specified for A, but a unit is specified only for Z, the unit for A and the unit for Z are the same.

[0023] ≪Surface coating layer for fixing member≫ The surface coating layer for the fixing member relating to this disclosure is A surface coating layer for a fixing member, The above surface coating layer consists of a resin composition. The above resin composition comprises at least one resin selected from the group consisting of polyethylene, polyetheretherketone, polyimide, polyamideimide, polymethylpentene, polyolefin, polyphenylene sulfide, polysulfone, polyetherimide, polyarylate, polyethersulfone, and polyethernitrile. The surface coating layer for the above-mentioned fixing member is irradiated with radiation in a low-oxygen atmosphere at a temperature above its melting point. The pencil hardness of the above surface coating layer is HB or higher.

[0024] Figure 3 is a schematic cross-sectional view showing a resin tube (hereinafter sometimes simply referred to as "resin tube") which is an example of a surface coating layer for a fixing member according to this embodiment. The shape of the resin tube 11 according to this embodiment is typically cylindrical.

[0025] The thickness, outer diameter, length, etc., of the resin tube described above can be appropriately selected according to the desired mechanical strength, application, etc. Here, the thickness of the resin tube refers to the shortest distance between the outer and inner surfaces of the resin tube. When the resin tube according to this embodiment is used as the surface layer of a fixing belt in an electrophotographic image forming apparatus, the thickness of the resin tube (thickness of the surface coating layer) may be 1 to 500 μm, 5 to 100 μm, or 10 to 50 μm. The outer diameter of the resin tube may be 5 to 100 mm or 10 to 50 mm. The length of the resin tube can be appropriately set according to the size of the transfer material, such as copy paper.

[0026] In this embodiment, the resin tube is used as a fixing member. Here, "fixing member" means a member used in a fixing process to fix an unfixed toner image to a transfer material in an image forming process using an electrophotographic method. Examples of the fixing member include fixing rollers, fixing belts, pressure rollers, and pressure belts. That is, in this embodiment, the fixing member may be a fixing roller, a fixing belt, a pressure roller, or a pressure belt. For fixing rollers and pressure rollers, for example, a core metal made of aluminum, iron, etc., is used as the base material of the roller, and the resin tube is provided on the outer circumference of the base material. For fixing belts and pressure belts, for example, a tube made of polyimide or thin-walled SUS is used as the base material, and the resin tube is provided on the outer circumference of the base material. The resin tube according to this embodiment can be used as the outermost layer (release layer) of a fixing roller or fixing belt.

[0027] <Resin composition> (Resin components) The resin composition according to this embodiment comprises at least one resin selected from the group consisting of polyethylene (PE), polyetheretherketone (PEEK), polyimide (PI), polyamideimide (PAI), polymethylpentene (PMP), polyolefin, polyphenylene sulfide (PPS), polysulfone (PSF·PSU), polyetherimide (PEI), polyarylate (PAR), polyethersulfone (PES), and polyethernitrile (PEN). These resins may be manufactured by known methods or purchased commercially.

[0028] The resin content ratio is not particularly limited as long as the effects of this disclosure are achieved, and can be set appropriately depending on the intended use of the resin tube.

[0029] (Other ingredients) In one aspect of this embodiment, the resin composition may further contain other components to the extent that the effects of the present disclosure are achieved. Examples of other components include resins other than those described above, fillers (e.g., high thermal conductivity fillers, conductive fillers, and wear-resistant fillers), and crosslinking aids (e.g., TAIC).

[0030] If the above resin composition contains a crosslinking aid, the presence of the crosslinking aid can be confirmed by gas chromatography.

[0031] <Physical properties of the surface coating layer for fixing members> The surface coating layer for the fixing member according to this embodiment (for example, the outer surface of a resin tube) is irradiated with radiation in a low-oxygen atmosphere at a temperature above its melting point. Therefore, it has the following physical properties.

[0032] (Pencil hardness) The pencil hardness of the above surface coating layer is HB or higher. Pencil hardness is measured according to JIS K 5600-5-4:1999.

[0033] (Thermal conductivity) In this embodiment, the thermal conductivity of the surface coating layer may be 0.4 W / mk or higher, or 0.6 W / mk or higher. The thermal conductivity can be determined, for example, by measuring the thermal diffusivity, density, and specific heat capacity of the surface coating layer using the following method and multiplying them together. i) Thermal diffusivity The thermal diffusivity of the surface coating layer will be measured using the ai-phase mobile 1u (product name) manufactured by i-phase Co., Ltd. The measurement temperature will be 23°C. ii) Density The density of the surface coating layer will be measured according to the underwater displacement method of JIS K 7112:1999 Method A. Ethanol will be used as the immersion solution. iii) Specific heat capacity The specific heat capacity of the surface coating layer is measured using input-compensated differential scanning calorimetry as defined in JIS K 7123:2012.

[0034] Microhardness The microhardness of the above surface coating layer is 50° or higher. Microhardness is measured using a microhardness tester (MD-1).

[0035] <Configuration of fixing member> In this embodiment, the surface coating layer for the fixing member can use an adhesive layer between it and the substrate. Examples of adhesive layers include polyamide (PA), polyamide-imide (PAI), and polyethersulfone (PES). These can be used individually, in combination, or blended with carbon, etc. Methods for molding onto a substrate include applying a mixed paint, powder coating, or injection molding.

[0036] <Embodiment of a surface coating layer for a fixing member> In this embodiment, the following configurations of the fixing method are provided when the surface coating layer for the fixing member is provided on the outer circumference of the fixing roller or fixing belt (Figure 2). The surface coating layer for the fixing member is used as the outermost layer (release layer) of the fixing roller or fixing belt.

[0037] First, one method involves using a blade 8 to scoop up and remove toner adhering to the outer surface of the fuser roller 1 (or fuser belt 1) (for example, Figure 2(A)). When using a fuser belt 1, a backup member 7 may be provided on the back surface of the fuser belt 1 that is in contact with the blade 8. Alternatively, a heater 2' and a backup member 7' may be provided in front of the blade 8 to preheat and melt the toner adhering to the fuser roller 1 before removing it with the blade 8 (for example, Figures 2(D), (E)).

[0038] Secondly, there is a method in which toner adhering to the outer surface of the fuser roller 1 (or fuser belt 1) is wiped off with the web 9 (for example, Figure 2(B)). When using a fuser belt 1, a backup member 7 may be provided on the back surface of the surface of the fuser belt 1 that is in contact with the web 9. Alternatively, a heater 2' and a backup member 7' may be provided in front of the web 9 to preheat and melt the toner adhering to the fuser roller 1 before it is removed by the web 9 (for example, Figure 2(C)).

[0039] To ensure the release properties of the fuser roller 1 (or fuser belt 1) from the toner, a coating device (not shown) for applying a release agent to the outer surface of the fuser roller 1 may be provided. Alternatively, the release agent may be pre-impregnated into the web 9, and the release agent may be applied to the outer surface at the same time as the toner is removed. Examples of components contained in the release agent include wax components (e.g., paraffinic wax, esteric wax, etc.) and silicone oil, which are also contained in the toner.

[0040] ≪Method for manufacturing resin tubes for fixing members≫ The method for manufacturing a resin tube for a fixing member according to this disclosure is: A step of preparing a resin tube made of a resin composition, The process involves irradiating the outer surface of the above-mentioned resin tube with radiation in a low-oxygen atmosphere at a temperature above its melting point, Includes, The above resin composition contains at least one resin selected from the group consisting of PE (polyethylene), PEEK (polyether ether ketone), PI (polyimide), PAI (polyamide imide), PMP (polymethylpentene), polyolefin, PPS (polyphenylene sulfide), PSF·PSU (polysulfone), PEI (polyetherimide), PAR (polyarylate), PES (polyethersulfone), and PEN (polyethernitrile).

[0041] <Preparing the resin tube> In this process, a resin tube made of the above-mentioned resin composition is prepared. The composition of the resin composition is as described above. The resin tube may be prepared as is, or it may be prepared in a state where it is attached to the substrate (for example, as a fixing roller or fixing belt).

[0042] Furthermore, the surface coating layer may be manufactured from raw materials by known methods. For example, first, a raw material composition (dispersion) is prepared by uniformly dispersing resin powder in a dispersant or the like. Examples of the dispersant include a mixture of water and an emulsifier, a mixture of water and alcohol, a mixture of water and acetone, and a mixed solution of water, alcohol, and acetone. Next, the raw material composition is applied to the outer surface of the cylindrical core and dried. After the coating layer of the raw material composition has dried, it may be heat-cured while still attached to the core surface, or, once it has solidified to a strength sufficient to maintain its tubular structure, the coating layer may be removed from the core surface and then heat-cured in the next step. As another method for applying the raw material composition to the outer surface of the cylindrical core, for example, a method of forming the coating layer using a dispenser (dispenser method) can be mentioned.

[0043] <Process of irradiating with radiation> In this process, the outer surface of the resin tube is irradiated with radiation in a low-oxygen atmosphere at a temperature above its melting point. For example, with the resin tube 21 formed on the inner surface of the cylindrical core 22 before irradiation (for example, Figure 4), radiation is irradiated from the outer surface of the cylindrical core 22 in a low-oxygen atmosphere at a temperature above its melting point (for example, Figure 5). Alternatively, with the resin tube formed on the outer surface of the cylindrical core before irradiation, radiation is irradiated from the outer surface of the cylindrical core 22 in a low-oxygen atmosphere at a temperature above its melting point.

[0044] In this embodiment, the radiation can be ionizing radiation such as gamma rays, electron beams, X-rays, neutron beams, or high-energy ion beams. The radiation may also be an electron beam. The lower limit of the irradiation dose of ionizing radiation may be 10 kGy or more, 70 kGy or more, or 260 kGy or more. If the irradiation dose is less than the lower limit, the crosslinking reaction of the resin tends not to proceed sufficiently. On the other hand, the upper limit of the irradiation dose may be, for example, 2000 kGy or less, 1200 kGy or less, or 400 kGy or less, in order to prevent the irradiation dose from becoming unnecessarily high.

[0045] The irradiation temperature of the above-mentioned radiation should be at or above the melting point of the above-mentioned resin tube.

[0046] In this embodiment, "low-oxygen atmosphere" means an atmosphere in which the oxygen concentration is 100 ppm by volume or less. The oxygen concentration may be 10 ppm by volume or less, or 5 ppm by volume or less. The lower limit of the oxygen concentration is not particularly limited, but may be, for example, 0 ppm by volume or more. Examples of the main gas components in a low-oxygen atmosphere include nitrogen gas and inert gases (e.g., argon gas).

[0047] <Other processes> The method for manufacturing a resin tube for a fixing member according to this embodiment may include other steps besides those described above. Other steps include, for example, a step of performing other surface treatments on the resin tube, such as chemical modification or plasma treatment, before irradiating it with radiation; a step of coating the irradiated resin tube onto a substrate; and a step of heating the coated resin tube to shrink it.

[0048] When coating a resin tube onto a substrate, an adhesive layer can also be used. Examples of adhesive layers include polyamide (PA), polyamide-imide (PAI), and polyethersulfone (PES). These can be used individually, in combination, or blended with carbon, etc. Methods for molding onto a substrate include applying a mixed paint, powder coating, or injection molding.

[0049] In the case of coating, one can choose a method that involves increasing the diameter through expansion, coating the material, and then shrinking it through heat treatment.

[0050] <<Aspect 2 of the surface coating layer>> After extruding the tube, it may be coated onto the substrate before electron beam irradiation. Alternatively, an adhesive layer may be used between the substrate and the tube.

[0051] In the case of coating, one can choose a method that involves increasing the diameter through expansion, coating the material, and then shrinking it through heat treatment.

[0052] <<Aspect 3 of the surface coating layer>> The surface coating layer may be applied as a paint to the substrate and then irradiated with an electron beam. Alternatively, after painting, the resin may be melted by a predetermined heat treatment before electron beam irradiation to form a coating film, and then irradiated with an electron beam. [Examples]

[0053] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

[0054] <<Preparation of surface coating layer for fixing member>> A surface coating layer was formed on a substrate using a known method from a raw material composition containing polyolefin.

[0055] <Process of irradiating with radiation> Under a low-oxygen atmosphere, the above surface coating layer was irradiated with radiation to obtain a surface coating layer for the fixing member. The irradiation temperature at this time was 150°C (below the melting point of polyolefin) or 240°C (above the melting point of polyolefin). <Analysis of physical properties of surface coating layers for fixing members> The pencil hardness and thermal conductivity of the obtained surface coating layer were measured using the method described below. The results are shown in Table 1.

[0056] (1) Measurement of pencil hardness Measurements were taken in accordance with JIS-K-5600-5-4 (1999) (see the pencil hardness column in Table 1).

[0057] (2) Measurement of thermal conductivity The thermal diffusivity, density, and specific heat capacity of each surface coating layer were measured using the following method, and these values ​​were multiplied together to obtain the thermal conductivity (W / mk) (see the "Thermal Conductivity" column in Table 1). i) Thermal diffusivity The thermal diffusivity of the surface coating layer was measured using ai-phase mobile 1u (product name) manufactured by i-phase Co., Ltd. The measurement temperature was 23°C. ii) Density The density of the surface coating layer was measured according to the underwater displacement method of JIS K 7112:1999 Method A. Ethanol was used as the immersion solution. iii) Specific heat capacity The specific heat capacity of the surface coating layer was measured using input-compensated differential scanning calorimetry according to JIS K 7123:2012.

[0058] [Table 1]

[0059] The results in Table 1 confirm that electron beam irradiation in a low-oxygen atmosphere at a temperature above the melting point improves the pencil hardness and thermal conductivity of the surface coating layer. In other words, the above surface coating layer exhibits excellent wear resistance and is suggested to be suitable as a surface coating layer for fixing members.

[0060] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the embodiments described above, and all modifications within the meaning and scope of the claims are intended to be included. [Explanation of Symbols]

[0061] 1. Fixing roller, fixing belt 2. Heat source, heater 3. Pressure roller 4 Transferred material 5. Image of unfixed toner 6. Fixing toner image 7, 7' Backup component 8 blades 9 Web 11. Resin tube (surface coating layer) 21. Resin tube (surface coating layer) before radiation irradiation 22. Cylindrical core.

Claims

1. A surface coating layer for a fixing member, The aforementioned surface coating layer consists of a resin composition, The resin composition comprises at least one resin selected from the group consisting of polyethylene, polyetheretherketone, polyimide, polyamideimide, polymethylpentene, polyolefin, polyphenylene sulfide, polysulfone, polyetherimide, polyarylate, polyethersulfone, and polyethernitrile. The surface coating layer for the fixing member is irradiated with radiation in a low-oxygen atmosphere at a temperature above its melting point. A surface coating layer for a fixing member, wherein the pencil hardness of the surface coating layer is HB or higher.

2. The surface coating layer for a fixing member according to claim 1, wherein the thermal conductivity of the surface coating layer is 0.4 W / mk or more.

3. The surface coating layer for a fixing member according to claim 1 or claim 2, wherein the microhardness of the surface coating layer is 50° or more.

4. The surface coating layer for a fixing member according to claim 1 or claim 2, wherein the thickness of the surface coating layer is 1 μm or more and 500 μm or less.

5. A fixing roller comprising a surface coating layer for a fixing member according to claim 1 or claim 2.

6. A pressure roller comprising a surface coating layer for a fixing member according to claim 1 or claim 2.

7. A method for manufacturing a resin tube for a fixing member, A step of preparing a resin tube made of a resin composition, The process involves irradiating the outer surface of the resin tube with radiation in a low-oxygen atmosphere at a temperature above its melting point, Includes, A method for producing a resin tube for fixing members, wherein the resin composition comprises at least one resin selected from the group consisting of polyethylene, polyetheretherketone, polyimide, polyamideimide, polymethylpentene, polyolefin, polyphenylene sulfide, polysulfone, polyetherimide, polyarylate, polyethersulfone, and polyethernitrile.

Images