Abrasion-resistant member, fixing device, image forming apparatus, and method for manufacturing the abrasion-resistant member.

Abstract

This prevents the exposure of the metal substrate and the peeling of the abrasion-resistant layer due to wear of the abrasion-resistant layer over long-term use. [Solution] The friction-bearing member 304 has a metal base material 304a having a surface provided with a plurality of base material protrusions 405, and a friction-bearing layer 304b covering the surface provided with the base material protrusions. The height H of the surface protrusions 406 formed by the base material protrusions and the friction-bearing layer is 230 μm or more. The diameter d of the tip region 405a of the base material protrusions is 400 μm or less. The rising angle θ of the base material protrusions is 35° to 80°. When any base material protrusion is taken as base material protrusion X, and the base material protrusion closest to base material protrusion X is taken as base material protrusion Y, the center-to-center distance W (mm) between the center of base material protrusion X and the center of base material protrusion Y is 1.2 or less. The relationship W × 1000 > d + 2 (H1 / tanθ) is satisfied. The thickness hA of the friction-bearing layer in the tip region of the surface protrusions is greater than the thickness hB of the friction-bearing layer covering the flat portion 407 between the base material protrusions.

Description

[Technical Field]

[0001] This disclosure relates to a member to be scraped, a fixing device, an image forming apparatus equipped with the fixing device, and a method for manufacturing the member to be scraped. [Background technology]

[0002] In recent years, the on-demand printing market has been expanding, with companies printing commercial materials such as catalogs, posters, and brochures in the required quantities, as well as continuously printing various invoices and direct mail with some of the content customized for each customer. Recently, there has been a growing demand for even faster printing speeds from electrophotographic image forming machines, which are essential for on-demand printing.

[0003] To achieve even faster printing speeds, it is necessary to apply sufficient energy to the unfixed toner image on the recording material, such as paper, in a short amount of time to fix it to the material. One method for achieving this is to use a fuser with a wide fuser nip, which allows energy to be applied to the unfixed toner image for a relatively longer period of time. Here, the width of the fuser nip refers to the length of the contact area between the fixing rotating body for heating the unfixed toner image and the pressing rotating body positioned opposite the fixing rotating body, in the direction along the transport direction of the recording medium. Hereafter, a fuser with a wide fuser nip may also be referred to as a wide-nip fuser.

[0004] In such wide-nip fixing devices, ensuring excellent image quality requires more reliable prevention of slippage between the fixing rotating body and the recording medium, as well as between the pressing rotating body and the recording medium.

[0005] Furthermore, as a fixing device, (i) an endless, rotatable belt (rotating body for fixing), (ii) A pressurizing member that forms a nip portion for gripping and transporting the recording medium between itself and the belt, (iii) In the nip portion, a backup member that rubs against the inner circumferential surface of the belt, A fixing device equipped with this is known.

[0006] Furthermore, in order to reduce the sliding resistance between the backup member and the belt, a configuration has been proposed in which a friction-bearing member is used between the backup member and the belt (Patent Documents 1 and 2). To further reduce the sliding resistance between the inner circumferential surface of the belt and the friction-bearing surface of the friction-bearing member, lubricating oil or grease is applied to and supplied to the inner circumferential surface of the belt as a lubricant.

[0007] Furthermore, regarding the surface of the abraded member, surface materials and surface shapes for the abraded member have been proposed to reduce sliding resistance. For example, Patent Document 1 uses a low-friction material as the surface material of the abraded member and reduces sliding resistance by forming an uneven surface.

[0008] The driving torque of a belt is greatly affected by sliding resistance, so in order to reduce the driving torque, it is necessary to reduce sliding resistance. Therefore, a configuration has been proposed in which the surface of the friction-bearing member that contacts the inner circumference of the belt is provided with multiple protrusions, and further, a friction-bearing layer is formed on the protrusions to reduce the driving torque. However, there is a concern that the friction-bearing layer will wear away due to prolonged use, causing the driving torque to increase. Therefore, Patent Document 2 discloses a configuration for a friction-bearing member in which the thickness of the friction-bearing layer on the protrusions is increased by defining the width of the tip surface of the protrusions, and in which the torque does not increase even after durability has been maintained.

[0009] In a friction-working member with multiple independent protrusions, the recesses are interconnected. This has the advantage that foreign matter, such as wear debris from the belt or friction layer, is less likely to get caught in the contact area between the surface of the friction-working member and the inner circumferential surface of the belt, and that the oil has good fluidity. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Japanese Patent Publication No. 2008-275927 [Patent Document 2] Japanese Patent Application Laid-Open No. 2023-125019

Summary of the Invention

Problems to be Solved by the Invention

[0011] In an electrophotographic image forming apparatus suitable for on-demand printing, further improvement in durability is required in accordance with the increase in printing speed. When a fixing device provided with a rubbing member is used for a long period of time, the rubbed layer on the tip surface of the convex portion is worn, and the height of the convex portion becomes lower. As a result, foreign matter caused by wear debris of the belt or the rubbed layer may be caught between the belt and the rubbed member, causing uneven pressure and resulting in image defects. In addition, the rubbed layer may peel off from the edge portion on the upstream side in the transport direction of the tip surface of the convex portion, and torque increase may occur due to the exposure of the metal layer of the base material of the convex portion. This is considered to be due to the fact that the thickness of the rubbed layer at the edge of the tip surface of the convex portion is relatively thinner than the thickness of the rubbed layer at the central portion of the tip surface of the convex portion. That is, in order to further improve the durability of the rubbed member, there is room for improvement in the thickness of the rubbed layer.

Means for Solving the Problems

[0012] A rubbed member according to one aspect of the present invention includes a metal base material having a surface provided with a plurality of base material convex portions, a rubbed layer covering the surface of the metal base material provided with the plurality of base material convex portions, and is a rubbed member having the height H of the surface convex portion formed by the base material convex portion and the rubbed layer covering the base material convex portion is 230 μm or more, the diameter d of the tip region of the base material convex portion is 400 μm or less, the rising angle θ of the base material convex portion is 35° to 80°, when any base material convex portion is defined as base material convex portion X and the base material convex portion closest to the base material convex portion X is defined as base material convex portion Y, the center-to-center distance W (mm) between the center of the base material convex portion X and the center of the base material convex portion Y is 1.2 or less, The height H1 of the protrusion on the base material, the diameter d, the rising angle θ, and the distance between centers W satisfy the relationship W × 1000 > d + 2(H1 / tanθ), The thickness hA of the abrasion layer in the tip region of the surface protrusion is greater than the thickness hB of the abrasion layer covering the portion between the substrate protrusion and the substrate protrusion. It is characterized by the following:

[0013] A fixing device according to one aspect of the present invention is: A fixing device for fixing an unfixed toner image supported on a recording material to the recording material, A rotating body for fixing, A pressing rotating body is positioned opposite the fixing rotating body and together with the fixing rotating body forms a nip portion, The abraded member is positioned inside the fixing rotating body and has a sliding surface that can contact the inner circumferential surface of the fixing rotating body via a lubricant, A pressing member is positioned inside the fixing rotating body and presses the fixing rotating body against the pressing rotating body via the friction-bearing member, A heater for heating the aforementioned rotating fixing body, Equipped with, The surface of the abrasion-resistant member having the surface protrusion is positioned opposite the inner circumferential surface of the fixing rotating body. [Effects of the Invention]

[0014] According to one aspect of this disclosure, it is possible to provide a friction-resistant member and a fixing device that can suppress the exposure of the metal substrate and the peeling of the friction-resistant layer due to wear of the friction-resistant layer even during long-term use. [Brief explanation of the drawing]

[0015] [Figure 1] Cross-sectional view of an image forming apparatus. [Figure 2] Cross-sectional view of the fixing device. [Figure 3] An enlarged cross-sectional view of the region including the nip area enclosed by the dotted line in Figure 2. [Figure 4] A partially enlarged cross-sectional view of the friction-applied component. [Figure 5] A distribution diagram of multiple base material protrusions provided on the friction surface of the friction-stricken member. [Figure 6] Enlarged cross-sectional view of the edge of the tip region of the protrusion on the base material of the friction-applied member. [Modes for carrying out the invention]

[0016] In this specification, descriptions of numerical ranges such as "XX or greater and YY or less" or "XX to YY" mean a numerical range that includes its endpoints, the lower and upper limits. Furthermore, when numerical ranges are described in steps, the upper and lower limits of each numerical range can be any combination. In this disclosure, for example, a description such as "at least one selected from the group consisting of XX, YY, and ZZ" means any of XX, YY, ZZ, a combination of XX and YY, a combination of XX and ZZ, a combination of YY and ZZ, or a combination of XX, YY, and ZZ.

[0017] Hereinafter, one embodiment of the fixing friction member 304 and one embodiment of the fixing device 8 according to the present disclosure will be described with reference to Figures 2 and 3. Figure 2 is a cross-sectional view of the fixing device 8. In Figure 2, the X direction is the transport direction of the recording material P, the Y direction is the direction intersecting the transport direction of the recording material P (the width direction of the recording material P), and the Z direction is the pressurizing direction in which the recording material P is pressurized at the nip portion N. In this embodiment, the X, Y, and Z directions are each orthogonal to each other. Figure 3 is an enlarged cross-sectional view of the region NA including the nip portion N enclosed by the dotted line in Figure 2.

[0018] The fixing device 8 includes a fixing rotating body 301, a pressure stay (hereinafter referred to as "stay") 302, a pressure pad (hereinafter referred to as "pad") 303, a friction member 304, a pressure rotating body 305, a heater 306, a heating roller 307, and a thermistor 308. The fixing rotating body 301 can be, for example, an endless belt. The pressure rotating body 305 contacts the outer circumferential surface of the fixing rotating body 301 to pressurize the fixing rotating body 301 and forms a nip section N that grips and transports the recording material P between itself and the fixing rotating body 301. The fixing rotating body 301 rotates in the rotational direction RD1, and the pressure rotating body 305 rotates in the rotational direction RD2.

[0019] The abraded member 304 slides against the inner circumferential surface of the fixing rotating body 301 at the nip portion N. The pad 303, acting as a backup member (pressing member), is positioned inside the fixing rotating body 301 so as to sandwich the abraded member 304 and the fixing rotating body 301 between itself and the pressing rotating body 305, thereby backing up the abraded member 304. The abraded member 304 is positioned to cover the side of the pad 303 facing the fixing rotating body 301 (hereinafter also referred to as the "outer surface"). The abraded member 304 is attached so as to cover at least the position on the outer surface of the pad 303 corresponding to the nip portion N. The abraded member 304 may be provided over the entire outer surface of the pad 303, or it may be attached only to the portion corresponding to the nip portion N.

[0020] The stay 302 is positioned inside the fixing rotating body 301, on the opposite side of the nip portion N, with the pad 303 in between, and supports the pad 303. The heating roller 307 is positioned inside the fixing rotating body 301 to tension the fixing rotating body 301 and heats the fixing rotating body 301. The thermistor 308, acting as a temperature sensing member, detects the temperature of the fixing rotating body 301.

[0021] The fixing rotating body 301 has thermal conductivity and heat resistance, and has a thin-walled cylindrical shape. In this embodiment, as shown in Figure 3, the fixing rotating body 301 has a base layer 301a, an elastic layer 301b covering the outer surface of the base layer 301a, and a release layer 301c covering the outer surface of the elastic layer 301b. The base layer 301a can be, for example, a polyimide resin (PI) layer with a thickness of 80 μm. The elastic layer 301b can be, for example, a layer containing silicone rubber with a thickness of 300 μm. The release layer 301c can be, for example, a fluororesin layer with a thickness of 30 μm. Examples of fluororesins include tetrafluoroethylene-perfluoroalkoxyethylene copolymer resin (PFA) and tetrafluoroethylene-hexafluoropropylene copolymer (FEP). The fixing rotating body 301 is stretched by a pad 303 and a heating roller 307. The outer diameter of the fixing rotating body 301 can be, for example, 150 mm.

[0022] The pad 303 is positioned inside the fixing rotating body 301 so as to face the pressurizing rotating body 305 with the fixing rotating body 301 in between, and a nip portion N is formed between the fixing rotating body 301 and the pressurizing rotating body 305 to hold and transport the recording material P. In this embodiment, the pad 303 is a substantially plate-shaped member that is long along the width direction of the fixing rotating body 301 (the longitudinal direction intersecting the rotation direction RD1 of the fixing rotating body 301 (Figure 2), and the rotation axis direction of the heating roller 307). The nip portion N is formed when the pad 303 is pressed by the pressurizing rotating body 305 with the fixing rotating body 301 in between. As the material of the pad 303, for example, LCP (liquid crystal polymer) resin can be used. A friction-bearing member 304 is interposed between the pad 303 and the fixing rotating body 301. Details of the friction-bearing member 304 will be described later.

[0023] The pad 303 is supported by a stay 302, which acts as a support member positioned inside the fixing rotating body 301. The stay 302 is positioned on the opposite side of the pad 303 from the pressurizing rotating body 305 and supports the pad 303. The stay 302 is a rigid reinforcing member that is long along the longitudinal direction of the fixing rotating body 301 and contacts the pad 303 to back it up. In other words, when the pad 303 is pressed by the pressurizing rotating body 305, the stay 302 provides strength to the pad 303 and ensures the applied pressure at the nip portion N.

[0024] The stay 302 is made of a metal such as stainless steel, and its cross-section (transverse plane) perpendicular to the longitudinal direction of the stay 302 that intersects with the rotational direction RD1 of the fixing rotating body 301 is substantially rectangular. For example, it is preferable to ensure strength by using a drawn material of stainless steel (e.g., SUS304, etc.) with a wall thickness of 3 mm and forming the cross-section into a substantially square hollow shape. The stay 302 may also be formed into a substantially rectangular cross-section by combining multiple sheet metals and fixing them to each other by welding or the like. Furthermore, the material of the stay 302 is not limited to stainless steel as long as strength can be ensured.

[0025] The heating roller 307 is positioned inside the fixing rotating body 301 and, together with the pad 303, tensions the fixing rotating body 301. The heating roller 307 is a cylindrical member made of a metal such as aluminum or stainless steel, and a heater 306 for heating the fixing rotating body 301 is disposed inside it. The heater 306 can be any heater capable of heating the heating roller 307, such as a halogen heater or a carbon heater. The heating roller 307 is heated to a predetermined temperature by the heater 306.

[0026] The heating roller 307 has a pivot point near one end or the center in the longitudinal direction. By rotating the heating roller 307 around its pivot point relative to the fixing rotating body 301, the heating roller 307 generates a tension difference in the fixing rotating body 301 at the front and rear in the longitudinal direction, and also acts as a steering roller to control the position of the fixing rotating body 301 in the main scanning direction. Furthermore, the heating roller 307 is biased by a spring (not shown) supported by a frame (not shown), and also acts as a tension roller that applies a predetermined tension to the fixing rotating body 301.

[0027] In this embodiment, the heating roller 307 is formed, for example, from a stainless steel pipe with a thickness of 1 mm. When a halogen heater is used as the heater 306, one halogen heater may be used, but it is desirable to use multiple heaters in consideration of controlling the temperature distribution in the longitudinal direction (rotation axis direction) of the heating roller 307. Multiple halogen heaters have different light distributions in the longitudinal direction, and the lighting ratio is controlled according to the size of the recording material P. In this embodiment, three halogen heaters are arranged as the heater 306.

[0028] The fixing rotating body 301 is heated by a heating roller 307 heated by a heater 306, and controlled to a predetermined target temperature according to the type of recording material P based on the temperature detected by a thermistor 308. The thermistor 308 is positioned opposite the outer circumferential surface of the fixing rotating body 301 in the width direction of the fixing rotating body 301, near the center through which recording materials P of all sizes that can be fixed by the fixing device 8 pass. The thermistor 308 detects the temperature of the fixing rotating body 301, and the control unit 30 (Figure 1) controls the power supplied to the heater 306 so that the temperature detected by the thermistor 308 becomes the target temperature. The thermistor 308 may be a non-contact type sensor positioned in close proximity to the outer circumferential surface of the fixing rotating body 301, or it may be a contact type sensor positioned in contact with the outer circumferential surface of the fixing rotating body 301.

[0029] The pressurizing rotating body 305 also acts as a drive roller, contacting the outer circumferential surface of the fixing rotating body 301 and rotating in the rotational direction RD2, thereby applying driving force to the fixing rotating body 301. The fixing rotating body 301 may also be rotated in the rotational direction RD1 by driving the heating roller 307 with a drive source such as a motor (not shown). Alternatively, the application of driving force to the heating roller 307 may be omitted, and the fixing rotating body 301 may be rotated by the pressurizing rotating body 305, or the application of driving force to the pressurizing rotating body 305 may be omitted, and the fixing rotating body 301 may be rotated by the heating roller 307. In other words, the drive roller for the fixing rotating body 301 can be at least one selected from the group consisting of the pressurizing rotating body 305 and the heating roller 307.

[0030] The pressurizing rotating body 305 includes, for example, a core (shaft) 305c, an elastic layer 305b provided on the outer circumference of the core 305c, and a release layer 305a covering the outer circumference of the elastic layer 305b. The core 305c can be, for example, a stainless steel roller with a diameter of 72 mm. The elastic layer 305b can be, for example, a conductive elastic layer containing silicone rubber with a thickness of 8 mm. Furthermore, the release layer 305a can be, for example, a fluororesin layer with a thickness of 100 μm. An example of a fluororesin is tetrafluoroethylene-perfluoroalkoxyethylene copolymer resin (PFA). The pressurizing rotating body 305 is rotatably supported by the frame (not shown) of the fixing device 8, and a gear (not shown) is fixed to one end of the pressurizing rotating body 305, which is connected via the gear to a drive source (not shown) such as a motor and driven.

[0031] The fixing device 8 grips the recording material P, which carries the unfixed toner image, in the nip section N formed between the fixing rotating body 301 and the pressurizing rotating body 305, and heats the unfixed toner image while transporting the recording material P. In this way, the fixing device 8 fixes the toner image to the recording material P while gripping and transporting it. Therefore, the fixing device 8 needs to have both the function of applying heat and pressure and the function of transporting the recording material P. The pressurizing rotating body 305 is pressurized against the abraded member 304 via the fixing rotating body 301 by a biasing device (not shown). In this embodiment, the pressurizing force (NF) in the nip section N during image formation, that is, the load value applied to the pad 303 and the pressurizing rotating body 305, is 1600 N. The nip width (length) in the X direction (direction of transport of the recording material) of the nip section N is set to 24.5 mm, and the width in the Y direction (width direction of the recording material) is set to 326 mm.

[0032] The nip width of the nip portion N in the X direction (conveying direction) is formed when the abrasion member 304 is pressed by the pressurizing rotating body 305 via the fixing rotating body 301. The magnitude of the applied force (NF) in the nip portion N is not particularly limited to 1600N. However, in order to prevent slippage between the recording material P passing through the nip portion N and the fixing rotating body 301 or the pressurizing rotating body 305, the applied force (NF) in the nip portion N should be such that the fixing rotating body 301 is sufficiently pressed by the pressurizing rotating body 305. For example, it is preferable to set the load value applied to the pad 303 and the pressurizing rotating body 305 to 900N or more, and more particularly to 1600N or more.

[0033] [Abrasion-resistant component] The abraded member 304 will be described using Figures 3, 4, and 5. Figure 4 is a partially enlarged cross-sectional view of the abraded member 304. Figure 5 is a distribution diagram of the multiple base material protrusions 405 provided on the abraded surface of the abraded member 304. The abraded member 304 is fixed to the stay 302 via a pad 303 by fixing members such as screws (not shown). In this embodiment, the abraded member 304 and the pad 303 are separate components, but they may be integrated. In Figure 4, the base material protrusions 405 of the abraded member 304 are shown upside down compared to Figure 3 in order to explain them in detail. The abraded member 304 has a base material 304a having multiple base material protrusions 405 on one side of its surface, and an abraded layer 304b that covers the side of the base material 304a where the base material protrusions 405 are formed. In the following explanation, the substrate protrusion 405 covered with the abrasion-resistant layer 304b is referred to as the surface protrusion 406.

[0034] <Base material> The base material 304a preferably has sufficient strength and heat resistance to prevent deformation by the pressing force applied to the friction member 304 via the fixing rotating body 301 by the pressing rotating body 305. For this reason, the material of the base material 304a is preferably metal, specifically, for example, stainless steel, aluminum, aluminum alloy, nickel, nickel alloy, etc. Specifically, the base material 304a can be formed from stainless steel (for example, SUS304, etc.) with a thickness of 1.3 mm. Here, the thickness of the base material 304a refers to the thickness of the portion of the base material without the protrusion 405.

[0035] Multiple base material protrusions 405 constitute a part of the base material 304a. From the viewpoint of equalizing the pressure at the nip portion N, it is preferable that multiple base material protrusions 405 are arranged in the direction along the transport direction of the recording material (X direction) and in the direction intersecting the transport direction (Y direction) at the nip portion N. The surface protrusions 406 are arranged to achieve both a uniform pressure distribution and a reduction in the driving torque of the fixing rotating body 301. Figure 5(a) is an example of a distribution diagram of multiple base material protrusions 405 provided on the friction surface of a friction-scratched member 304 according to one embodiment of the present disclosure. The arrangement of base material protrusions 405 shown in Figure 5(a) is an example and is not limited thereto. As shown in Figure 5(a), the base material protrusions 405 are evenly arranged in the transport direction (X direction) and the direction intersecting the transport direction (Y direction). With respect to the direction intersecting the transport direction (Y direction), the multiple substrate protrusions 405 should be arranged such that the distance Vy between the substrate protrusions 405 is 2.0 mm or less, more preferably 1.7 mm or less. If the spacing between the substrate protrusions 405 is greater than 2.0 mm, a pressure distribution with significantly different pressures will occur in the width direction (Y direction) of the recording material P, and streaky image defects may be formed in the transport direction (X direction).

[0036] As shown in Figure 5(a), the multiple substrate protrusions 405 are arranged at equal intervals in the transport direction (X direction) and in the direction intersecting the transport direction (Y direction). In the example arrangement shown in Figure 5(a), the distance between the center of any substrate protrusion 405X and the center of the substrate protrusion 405Y that is closest to the substrate protrusion 405X is defined as the center-to-center distance W (mm). The distance between the centers of two adjacent substrate protrusions 405 in the Y direction is defined as the protrusion-to-protrusion distance Vy (mm). The relationship between the center-to-center distance W and the protrusion-to-protrusion distance Vy is expressed by the following equation. Vy = W / √2 × 2 Therefore, if the distance W (mm) between the centers of any substrate protrusion 405X (substrate protrusion X) and the substrate protrusion 405Y (substrate protrusion Y) closest to it is 1.2 or less, the distance Vy between protrusions in the Y direction will be 1.7 mm, which is 2.0 mm or less. Also, if the distance W between centers is less than 0.3 mm, adjacent substrate protrusions 405 will connect at the bottom surface and a flat portion 407 cannot be secured, so it is preferable that the distance W between centers be between 0.3 mm and 1.2 mm.

[0037] The shape of each of the multiple base material protrusions 405 is preferably a frustoconical shape. The frustoconical shape is suitable for facilitating the flow of a sufficient amount of lubricant 309 onto the tip region 406a of the surface protrusions 406, which contributes to reducing the driving torque of the fixing device 8. The tip region 405a of the base material protrusions 405 is a substantially flat circular shape, but the shape of the base material protrusions 405 is not particularly limited. As shown in Figure 4(a), the base material protrusions 405 can be a frustoconical shape in which the diameter D of the base surface is larger than the diameter d of the tip region 405a, which is the top surface. If the diameter d of the tip region 405a of the base material protrusions 405 is less than 150 μm, when the abraded member 304 is assembled into the fixing device 8 and used, it is pressurized and pressure is concentrated on the tip region 405a, making the abraded layer 304b of the tip region 405a more susceptible to wear. Furthermore, if the diameter d of the tip region 405a of the substrate protrusion 405 is greater than 400 μm, the contact area between the surface protrusion 406 and the fixing rotating body 301 increases, and the driving torque of the fixing rotating body 301 increases. Therefore, the preferred range for the diameter d of the tip region 405a of the substrate protrusion 405 is 150 μm or more and 400 μm or less.

[0038] Figure 6 is an enlarged cross-sectional view of the edge of the tip region 405a of the base material protrusion 405 of the friction-resistant member 304. As shown in Figure 6, the edge of the tip region 405a may have an R shape. In that case, the diameter d (μm) of the tip region 405a of the base material protrusion 405 is defined by the intersection of a horizontal line HL passing through the central part 405c of the tip region 405a and a tangent line TL of the inclined surface 405s at half the height H1 of the base material protrusion 405 (1 / 2H1).

[0039] As shown in Figure 4(a), the diameter D (μm) of the bottom surface of the base material protrusion 405 can be expressed by the following equation 1, using the diameter d of the tip region 405a of the base material protrusion 405, the height H1 of the base material protrusion 405, and the rising angle θ of the base material protrusion 405. D=d+2(H1 / tanθ) (Formula 1)

[0040] The friction-bearing member 304 is positioned inside the fixing rotating body 301 and has a friction surface that can contact the inner circumferential surface of the fixing rotating body 301 via a lubricant 309. It is preferable that the friction-bearing member 304 and the fixing rotating body 301 slide against each other via the lubricant 309. In this case, in order not to hinder the uniform flow of the lubricant 309, a flat portion 407 is formed between the base material protrusions 405 and the base material protrusions 405, and it is preferable that the flat portion 407 is of a uniform height. In order to ensure the flat portion 407, it is preferable that the following equation 2 is satisfied so that the base material protrusions 405 do not overlap. W×1000>d+2(H1 / tanθ) (Formula 2)

[0041] The rising angle θ of the base material protrusion 405 is preferably in the range of 35° to 80°. If the rising angle θ is less than 35°, it is necessary to widen the center-to-center distance W (mm) in order to secure a sufficiently large flat area 407. However, as mentioned above, if the center-to-center distance W (mm) is greater than 1.2, a uniform pressure distribution cannot be ensured. Also, if the rising angle θ is greater than 80°, the thickness of the friction-bearing layer 304b at the edge of the tip region 405a of the base material protrusion 405 becomes thinner, making it easier for the friction-bearing layer 304b to peel off. When the friction-bearing layer 304b peels off, the driving torque of the fixing rotating body 301 increases.

[0042] The height H of the surface protrusions 406 of the abraded member 304 is preferably 230 μm or more. This is to prevent image defects caused by pressure unevenness resulting from wear particles from the fixing rotating body 301 and wear particles from the abraded layer 304b, which are generated by long-term durability and get trapped in the nip portion N. Therefore, it is desirable to form the height of the base material protrusions 405 so that the height of the surface protrusions 406 after the abraded layer 304b is formed on the base material protrusions 405 is 230 μm or more. The manufacturing method of the base material 304a having multiple base material protrusions 405 is not particularly limited, but examples include chemical etching and press working.

[0043] <Rubbing layer> The friction-resistant layer 304b covers the surface of the base material 304a on the side where multiple base material protrusions 405 are located. The material constituting the friction-resistant layer 304b is not particularly limited, but a resin that has excellent heat resistance, wear resistance, and sliding properties with the inner circumferential surface of the fixing rotating body 301 is preferred. Specifically, for example, polyetheretherketone (PEEK) can be used. Furthermore, a fluororesin (PTFE (polytetrafluoroethylene), PFA, etc.) may be included to achieve even lower friction.

[0044] Regarding the thickness of the friction layer 304b of the friction member 304, it is preferable that the thickness hA of the friction layer 304b on the center of the tip region 405a of the base material protrusion 405 is greater than the thickness hB of the friction layer 304b on the flat portion 407. The surface protrusion 406 of the friction member 304 is rubbed by the inner surface 301i of the fixing rotating body 301, and the friction layer 304b on the surface protrusion 406 gradually wears away, exposing the base material 304a, thus ending the service life of the friction member 304. Therefore, increasing the thickness hA of the friction layer 304b in the tip region 406a of the surface protrusion 406 is expected to improve the service life. On the other hand, in order to avoid obstructing the flow of the lubricant 309 and to quickly remove wear particles from the friction layer 304b and the fixing rotating body 301 that are generated during long-term durability, it is desirable to ensure that the flat portion 407 between the surface protrusions 406 is wide. Also, as mentioned above, it is desirable to ensure that the height H of the surface protrusions 406 is 230 μm or more. That is, in order to ensure that the height H of the surface protrusions 406 is 230 μm or more, the thickness hB of the friction layer 304b in the flat portion 407 should be adjusted so that it is not excessively thick. The upper limit of the height H of the surface protrusions 406 is not particularly limited and may be as high as is possible within the range that can be processed. For example, the height H of the surface protrusion 406 may be 230 μm or more and 1000 μm or less, 230 μm or more and 500 μm or less, 230 μm or more and 300 μm or less, or 230 μm or more and 265 μm or less.

[0045] Furthermore, the thickness hC(hC) of the friction layer 304b formed on the edge of the tip region 405a of the base material protrusion 405 is F hC R The thickness hC of the friction layer 304b formed on the upstream edge 405f on the upstream side of the tip region 405a with respect to the direction of movement (rotation direction RD1, X direction, transport direction) of the fixing rotating body 301 that slides on the friction member 304 is set to thickness hC F The thickness hC of the friction layer 304b formed on the downstream edge 405r on the downstream side of the tip region 405a with respect to the direction of movement of the fixing rotating body 301 is defined as thickness hC RLet it be so. The thickness hC of the rubbed layer 304b formed on the upstream edge 405f on the upstream side of the tip region 405a F has a thickness of at least 30% or more of the thickness hA of the rubbed layer 304b formed on the center of the tip region 405a (hC F ≧0.3hA). This is because if the thickness hC of the rubbed layer 304b formed on the edge of the tip region 405a of the base material convex portion 405 is thin, peeling of the rubbed layer 304b is likely to occur. Also, the thickness hC of the rubbed layer 304b on the upstream edge 405f (one edge) F is the thickness hC of the rubbed layer 304b on the downstream edge 405r (the other edge) on the opposite side of the upstream edge 405f R is larger (hC F >hC R ). This is because the rubbed layer 304b on the upstream edge 405f (one edge) is more likely to wear than the rubbed layer 304b on the downstream edge 405r (the other edge).

[0046] <Manufacturing method of the rubbed member> As a manufacturing method of the rubbed member 304 according to the present disclosure, for example, a method having the following steps I and II can be mentioned.

[0047] Step I: Prepare a base material 304a having a base material convex portion 405 on the surface of one side. The base material 304a can be manufactured by, for example, chemical etching or press working.

[0048] Step II: On the surface of the base material 304a prepared in Step I on the side where the base material convex portion 405 is formed, form a rubbed layer 304b as shown in FIG. 4(b). The method of forming the rubbed layer 304b is not particularly limited, and for example, the following methods (i) and (ii) can be mentioned. Method (i): A resin solution in which a resin for forming the rubbed layer 304b is dissolved in an appropriate solvent is applied onto the surface of the base material 304a on the side where the base material convex portion 405 is formed to form a coating film of the resin solution. Subsequently, the coating film is dried to form the rubbed layer 304b. Method (ii): A resin dispersion for forming the abrasion-resistant layer 304b is applied to the surface of the substrate 304a on the side where the substrate protrusions 405 are formed to form a coating of the dispersion. Subsequently, the coating is dried and fired to form the abrasion-resistant layer 304b.

[0049] To improve the durability and lifespan of the abraded member 304 and to facilitate the rapid removal of wear debris, in step II, the abraded layer 304b on the tip region 405a is formed such that the thickness hA of the abraded layer 304b on the flat portion 407 is greater than the thickness hB of the abraded layer 304b on the flat portion 407 (hA > hB). Here, the thickness hB of the abraded layer 304b will be explained using Figure 5. First, an arbitrary base material protrusion 405X is selected from a plurality of base material protrusions 405. Concentric circles are drawn from the center 405cX of the tip region 405aX of the base material protrusion 405X to determine the closest base material protrusion 405Y. The thickness of the abraded layer 304b on the flat portion 407 at the midpoint Lc of the line L connecting the center 405cX of the base material protrusion 405X and the center 405cY of the tip region 405aY of the base material protrusion 405Y is defined as thickness hB. When multiple base material protrusions 405Y exist relative to the base material protrusion 405X, the thickness hB of the abraded layer 304b at the midpoint Lc for each of the multiple base material protrusions 405Y is calculated. The average of the multiple calculated thicknesses hB is taken as the thickness hB of the flat portion 407 with respect to the thickness hA of the base material protrusion 405X. To observe the cross-section of the abraded member 304 taken along line L, a cross-section passing through the center 405cX of the base material protrusion 405X and the center 405cY of the base material protrusion 405Y is actually cut out, observed with an electron microscope (SEM), and the thicknesses hA and hB of the abraded layer 304b are measured.

[0050] Furthermore, as mentioned above, the thickness hC of the abrasion layer 304b at the upstream edge 405f and downstream edge 405r of the tip region 405a F and hC R These are the thicknesses on the upstream and downstream sides in the transport direction (X direction), respectively. The edge of the tip region 405a is defined by the intersection of a horizontal line HL passing through the central part 405c of the tip region 405a and a tangent line TL passing through half the height (1 / 2H1) of the inclined surface 405s of the base material protrusion 405, as shown in Figure 6. The thickness hC of the abrasion layer 304b at the upstream edge 405f and downstream edge 405r of the tip region 405a.F and hC R This is the distance between the intersection point and the foot of the perpendicular that passes through the intersection point and intersects the base material protrusion 405 perpendicularly.

[0051] The cross-section of the surface protrusion 406X is cut out to obtain the thicknesses hA, hB, and hC of the abrasion-affected layer 304b. F and hC R When measuring, depending on the arrangement of the multiple surface protrusions 406, the surface protrusion 406Y at the shortest distance may be in an oblique phase with respect to the X and Y directions. When the surface protrusion 406X is in an oblique phase with respect to the transport direction (X direction), the thickness hC of the abraded layer 304b at the upstream and downstream edges of the surface protrusion 406X F and hC R It is not possible to measure accurately. In that case, instead of cutting out the surface protrusion 406X which is cut out at an oblique phase, another surface protrusion 406 is cut out along the transport direction (X direction) and the thickness of the abrasion layer 304b is measured. Evaluation values ​​of the abrasion member 304 (hA, hB, hC F hC R These values ​​(etc.) are determined using the average value of the measurement results of several surface protrusions 406 and are treated as characteristic values ​​of the abraded member 304.

[0052] Relationship of the thickness of the abrasion-scratched layer 304b (hA>hB, hC F ≧0.3hA and hC F >hC RTo satisfy the above, it is desirable that the coating step of step II include, for example, the following steps. Specifically, step II may include a coating step of spray-applying a coating agent containing a resin for forming a friction-resistant layer 304b to the surface of the metal substrate 304a (metal substrate) obtained in step I on the side having the substrate protrusion 405. Step II may further include a firing step of firing the resin contained in the applied coating agent to form a resin layer. The coating step may be a step of applying the coating agent while rotating the substrate 304a so that the centrifugal force at the tip region 405a of the substrate protrusion 405 is 1.5G or more and 3.0G or less in the direction of the tip of the substrate protrusion 405. The firing step may include a heating step of heating the substrate 304a to above the melting point of the resin that forms the resin layer while the substrate 304a is placed in a direction in which gravity acts in the direction of the tip of the substrate protrusion 405, and a cooling step of cooling the substrate 304a while it remains placed in that direction. According to process II, the thicknesses hA, hB, and hC of the rubbed layer 304b F and hC R However, as mentioned above, hA > hB, hC F ≧0.3hA and hC F >hC R A friction-to-abrasion member 304 that satisfies the relationship can be obtained.

[0053] The method utilizing centrifugal force due to rotation allows for a more effective increase in the thickness hA of the abrasive layer 304b in the tip region 405a compared to the spray coating method with the surface of the substrate having the protrusions 405 facing downwards. However, if the centrifugal force is greater than 3.0G, the coating liquid will scatter, reducing the coating efficiency. Therefore, it is preferable to keep the centrifugal force below 3.0G. If the centrifugal force is less than 1.5G, the thickness hA of the abrasive layer 304b in the tip region 405a of the substrate protrusions 405 will not be sufficiently large. Therefore, it is preferable to keep the centrifugal force above 1.5G.

[0054] After applying the coating solution, the substrate 304a is rotated to allow some of the solvent to evaporate and dry. If the rotation is stopped while the coating solution is still at a low viscosity, the coating solution will flow in the direction of gravity at that moment, resulting in uneven thickness of the friction layer 304b. Therefore, before stopping the rotation, some of the solvent in the coating solution is allowed to evaporate and the surface is dried.

[0055] In the firing process for forming the resin layer, the substrate 304a is positioned so that stress (e.g., gravity) is applied in the direction of the tip of the substrate protrusion 405, and the substrate is heated to a temperature above the melting point of the resin forming the friction layer 304b. In the firing process, the resin forming the friction layer 304b is melted and coalesced to form a uniform film. At this time, if the substrate is fired at a temperature above the melting point with the surface on the side with the substrate protrusion 405 facing upwards, in a state where no stress is applied in the direction of the tip of the substrate protrusion 405, resin flow occurs from the tip region 405a of the substrate protrusion 405 to the flat portion 407. As a result, the thickness hC of the friction layer 304b at the edge of the tip region 405a of the substrate protrusion 405 is reduced. F and hC R The resin layer may thin, and in some cases, the resin may run out, exposing the metal surface of the substrate 304a itself. To counteract this, by firing the substrate so that stress is applied towards the tip of the substrate protrusion 405, it is possible to prevent the resin from flowing from the tip region 405a of the substrate protrusion 405 to the flat portion 407. This ensures sufficient thickness of the resin layer in the tip region 405a of the substrate protrusion 405, while preventing the resin layer from breaking down in the tip region 405a of the substrate protrusion 405, making it possible to form a highly durable abrasion-resistant layer 304b.

[0056] The thickness hA of the friction layer 304b at the tip region 405a of the base material protrusion 405 is not particularly restricted. However, in order to maintain the convex shape of the base material protrusion 405 and prevent the driving torque of the fixing rotating body 301 from becoming too large, the thickness hA is preferably, for example, 20 μm to 100 μm, and more preferably 20 to 60 μm.

[0057] Furthermore, the height H of the surface protrusions 406 of the abraded member 304 must be such that the difference in height H between adjacent surface protrusions 406 is small. Therefore, the abraded layer 304b may be smoothed at the tips of the surface protrusions 406 as needed. Methods for smoothing include heat pressing and polishing.

[0058] <Image forming apparatus> Hereinafter, an electrophotographic image forming apparatus (hereinafter also referred to as "image forming apparatus") according to one aspect of the present disclosure will be described with reference to Figure 1. Figure 1 is a cross-sectional view of the image forming apparatus 1. In the following description, an image forming apparatus 1 having a plurality of electrophotographic photosensitive drums and capable of forming a color image will be used as an example, but the image forming apparatus 1 is not limited to this and may be an image forming apparatus that forms a monochrome image.

[0059] The image forming apparatus 1 comprises a main body 3 and an image reading unit 2 located on the upper part of the main body 3. The image reading unit 2 comprises a document glass 21, a light source 22, an optical system component 23, a CCD sensor 24, and a reader control unit 25. The optical system unit 26 has a light source 22, an optical system component 23, and a CCD sensor 24, and is capable of reciprocating movement in the sub-scanning direction (direction indicated by the arrow). The image reading unit 2 reads the image of a document placed on the document glass 21. Light emitted from the light source 22 is reflected by the document and formed on the CCD sensor 24 via an optical system component 23 such as a lens. As the optical system unit 26 scans in the direction indicated by the arrow, the CCD sensor 24 converts the reflected light from the document into line-by-line image signals (electrical signal data sequences) and transmits them to the reader control unit 25. The image signals obtained by the CCD sensor 24 are transmitted from the reader control unit 25 to a control unit 30 located on the main body 3. The control unit 30 performs image processing on the image signal according to the respective image forming units Pa, Pb, Pc, and Pd, which will be described later. The control unit 30 can also receive image signals from an external host device (not shown), such as a print server. The image forming apparatus 1 can perform image forming operations according to instructions from the operation unit 4 or an external host device (not shown).

[0060] The main body 3 of the image forming apparatus 1 comprises a plurality of image forming units Pa, Pb, Pc, and Pd. Each of the plurality of image forming units Pa, Pb, Pc, and Pd performs image formation based on the image signal described above. In this disclosure, the image forming unit Pa forms a yellow (Y) image, the image forming unit Pb forms a magenta (M) image, the image forming unit Pc forms a cyan (C) image, and the image forming unit Pd forms a black (Bk) image. The control unit 30 generates pulse width modulated (PWM) pulse signals corresponding to each color based on the image signal. The control unit 30 controls the exposure device (polygon scanner) 31 based on the pulse width modulated pulse signals and outputs laser beams corresponding to each color from the exposure device 31. The laser beams output from the exposure device 31 are irradiated onto the photosensitive drums 200a, 200b, 200c, and 200d, which serve as image carriers for the image forming units Pa to Pd, respectively. Since the image forming sections Pa to Pd have substantially the same structure, the image forming section Pa will be described below, and the descriptions of the other image forming sections Pb, Pc, and Pd will be omitted.

[0061] The primary charger 201a uniformly charges the surface of the photosensitive drum 200a, which rotates in the direction indicated by the arrow, to a predetermined potential. The exposure apparatus 31 irradiates the surface of the uniformly charged photosensitive drum 200a with a pulse-width modulated laser beam according to image information to form an electrostatic latent image. The developer 202a develops the electrostatic latent image on the surface of the photosensitive drum 200a with yellow toner to form a yellow toner image. The primary transfer roller 203a discharges from the back of the intermediate transfer belt 204, applying a primary transfer bias with the opposite polarity to the toner, and transfers the toner image on the photosensitive drum 200a onto the intermediate transfer belt 204. Toner remaining on the surface of the photosensitive drum 200a after primary transfer is removed by the cleaner 207a.

[0062] The toner image on the intermediate transfer belt 204 is transported to the next image forming unit Pb, where a magenta toner image is transferred on top of the yellow toner image. Similarly, in the image forming units Pc and Pd, cyan and black toner images are transferred sequentially, forming four-color toner images superimposed on the surface of the intermediate transfer belt 204. The toner image that has passed through the image forming unit Pd is transported to the secondary transfer unit, which is composed of secondary transfer roller pairs 205 and 206. Meanwhile, the recording material P supplied from the feed cassette 9 waits in the registration unit 208, and then is transported from the registration unit 208 to the secondary transfer unit at a controlled timing to align the position of the toner image on the intermediate transfer belt 204 with the recording material P. In the secondary transfer unit, a secondary transfer electric field with the opposite polarity to the toner image on the intermediate transfer belt 204 is applied, and the toner image is transferred onto the recording material P. Subsequently, the toner image on the recording material P is heated and pressurized by the fixing device 8, which acts as an image heating device, and fixed to the recording material P. After passing through the fixing device 8, the recording material P is discharged into the discharge tray 7 provided in the image forming apparatus 1.

[0063] When the image formation mode is double-sided printing mode, after an image is formed on the first surface of the recording material P, the front and back of the recording material P are reversed by the reversal unit 11 located inside the image forming apparatus 1, and the recording material P is transported again to the secondary transfer unit via the double-sided transport path 10. In the secondary transfer unit, the toner image is transferred to the second surface of the recording material P, opposite to the first surface, and the toner image is fixed to the second surface of the recording material by the fixing unit 8. The recording material P, with images formed on both sides, is discharged to the discharge tray 7.

[0064] (Examples) The present disclosure will be specifically described below using examples. However, the abrasion-scratched member 304 and fixing device 8 according to the present disclosure are not limited to the configurations embodied in the following examples.

[0065] <Example 1> (Preparation of the base material) A plate-shaped base material 304a made of stainless steel (SUS304) was prepared, with a thickness of 1.3 mm, a width of 27.5 mm, and a length of 390 mm perpendicular to the width direction.

[0066] Next, a substrate protrusion 405 was formed on one surface of the substrate 304a by chemical etching. Each substrate protrusion 405 had a frustoconical shape with a tip region 405a diameter d of 350 μm, a height H1 of 250 μm, an angle of the inclined surface 405s (the rising angle of the substrate protrusion 405) of 70°, and a base diameter D of 532 μm. The multiple substrate protrusions 405 were arranged so that the distance W between the centers of the substrate protrusions 405 at the shortest distance from each other was set to 1.0 mm, and the spacing between the substrate protrusions 405 in the X and Y directions (interprotrusion distances Vx and Vy) were equal. The interprotrusion distances Vx and Vy in the X and Y directions of the substrate protrusions 405 were 1.4 mm.

[0067] (Formation of the abrasion layer) A dispersion of polyether ether ketone (PEEK) (product name: VICOTE® F817, manufactured by Victrex) was prepared. The viscosity of the paint was 63 mPa·s (23℃). Next, the substrate 304a prepared above was fitted onto the outer surface of a core with an outer diameter of 80 mm, and while rotating at 200 rpm, the dispersion was applied using a spray gun (product name: W-101, manufactured by Anest Iwata Corporation) to form a coating film of the dispersion. At this time, a centrifugal force of 1.9 G was generated at the tip region 405a of the substrate protrusion 405. After the coating was completed, the device was rotated for 10 minutes before being stopped and the substrate 304a was removed. Next, the substrate 304a with the coating film formed on it was placed in a heating furnace and heated at a temperature of 120℃ for 5 minutes. After the coating film was dried, the substrate 304a was heated at 400°C for 15 minutes to bake the coating film and form a first PEEK resin layer such that the thickness of the abrasion-stressed layer 304b on the tip region 405a of the substrate protrusion 405 was 10 μm.

[0068] The process involved applying a dispersion of polyether ether ketone (PEEK) (product name: VICOTE® F804, manufactured by Victrex Co., Ltd.) onto the first PEEK resin layer prepared as described above. The viscosity of the coating was 92 mPa·s (23°C). First, the substrate 304a prepared as described above was fitted onto the outer surface of a core with an outer diameter of 80 mm, and while rotating at 200 rpm, the dispersion was applied using a spray gun (product name: W-101, manufactured by Anest Iwata Co., Ltd.) to form a coating film of the dispersion. At this time, a centrifugal force of 1.9 G was generated in the tip region of the surface protrusion 406. After the coating was completed, the device was rotated for 10 minutes before being stopped and the substrate 304a was removed. Next, the substrate 304a with the coating film formed on it was placed in a heating furnace and heated at a temperature of 120°C for 5 minutes to dry the coating film. Subsequently, the substrate was placed in a heating furnace with the surface on which the substrate protrusions 405 were formed facing downwards and with a 15° inclination in the width direction. The substrate was then heated at 400°C for 15 minutes to bake the coating and form a second PEEK resin layer. The spray conditions were set so that the thickness of the resulting second PEEK layer was 50 μm. In this way, a friction-resistant layer 304b consisting of the first and second PEEK resin layers was formed on the surface of the substrate 304a on the side on which the substrate protrusions 405 were formed. The substrate protrusions 405 were covered with the friction-resistant layer 304b to form surface protrusions 406.

[0069] (smoothing process) Next, a smoothing process was performed to make the height of the surface protrusions 406 uniform. A base material 304a covered with the abrasion-resistant layer 304b was placed on a hot plate (600 mm long x 600 mm wide x 60 mm thick) heated to 200°C, which is above the glass transition temperature but below the melting temperature of the PEEK forming the abrasion-resistant layer 304b, so that the surface protrusions 406 were in contact with it. Using a hot press machine (product name: 150-ton press machine, model: PEF-150, manufactured by Kansai Roll Co., Ltd.), the abrasion-resistant layer 304b was pressed against the hot plate so that a pressure of 1.0 MPa was applied to the surface protrusions 406, and this state was maintained for 10 minutes. After that, the pressing state was released, and the abrasion-resistant layer 304b was left to stand in a room temperature (25°C) environment. In this way, the tip of the surface protrusions 406 was smoothed, the height variation was reduced, and the abrasion-resistant member 304 according to Example 1 was obtained.

[0070] The obtained friction-bearing members 304 were subjected to the following evaluations. Note that, since it was difficult to perform evaluations on identical individual members in Evaluation 1 and Evaluation 2, friction-bearing members 304 manufactured under the same conditions were treated as identical products for evaluation.

[0071] <Evaluation 1> Measurement of the thickness of the abraded layer First, the arrangement of the surface protrusions 406 was observed from the surface side of the abraded member 304 where the surface protrusions 406 are formed, and the closest adjacent surface protrusions 406 were selected. The arrangement of the surface protrusions 406 was observed and measured using a three-dimensional shape measuring machine. In Example 1, the distance between surface protrusions 406 was measured using a "One-Shot 3D Shape Measuring Machine VR-3200" (product name, manufactured by Keyence Corporation) as the three-dimensional shape measuring machine. First, an arbitrary surface protrusion 406X was selected from the surface side of the abraded member 304 where the surface protrusions 406 are formed. Concentric circles were drawn from the center point of the tip region of the surface protrusion 406X, and the surface protrusion 406Y at the shortest distance was extracted. After identifying the surface protrusions 406X and 406Y, the two surface protrusions 406X and 406Y were cut at a cross-section passing through the center points of their tip regions. The cross-sections of surface protrusions 406X and 406Y were observed using a scanning electron microscope (SEM) (product name: JSM-F100, manufactured by JEOL Ltd.), and the thickness of the abrasion-affected layer 304b was calculated.

[0072] <Evaluation 2> Drive durability test For this evaluation, a full-color electrophotographic image forming apparatus (product name: imagePRESS V1000; manufactured by Canon Corporation) was used. The drive durability test was performed in a mode in which the pressurizing rotating body 305 alternately contacted and did not contact the fixing rotating body 301. The design target time for this mode in Evaluation 2 was set to 500 hours. If the drive torque exceeded a predetermined upper limit within the design target time, the drive durability test was terminated. If the drive torque did not exceed the upper limit within the design target time, the drive durability test was terminated after the design target time had elapsed. The aforementioned upper limit of drive torque was set to 300 mNm, which is the threshold at which there is a risk of defective images due to slippage or damage to the drive gear.

[0073] For the evaluation, 50 ml of lubricant 309 was first applied to the surface of the friction-ridden member 304 on the side where the surface protrusion 406 was formed. Lubricant 309 contains perfluoropolyether (product name: Demnum S-200; manufactured by Daikin Corporation) as a base oil, and 30% by mass of fluororesin particles (product name: Rubron L-5F; manufactured by Daikin Corporation) as a thickener relative to lubricant 309. The kinematic viscosity of the above base oil at a temperature of 40°C is 200 mm². 2 It is / s.

[0074] Next, the friction-bearing member 304 fixed to the outer surface of the pad 303 of the fixing device 8 of the full-color electrophotographic image forming apparatus is removed. The lubricant 309 prepared above is applied to the surface of the removed friction-bearing member 304. The friction-bearing member 304 to be evaluated, with the lubricant 309 applied, is attached to the full-color electrophotographic image forming apparatus. The above drive durability test was performed using the full-color electrophotographic image forming apparatus. The durability test was conducted for up to 500 hours while acquiring torque data of the fixing rotating body 301, and the condition of the friction-bearing member 304 was observed every 50 hours.

[0075] The wear resistance and the condition of the abrasion-resistant member 304 were evaluated according to the following evaluation criteria. Abrasion resistance evaluation criteria Rank A: Drive torque less than 270 mNm at the end of 500 hours of endurance. Rank B: Drive torque of 270 mNm or more at the end of 500 hours of endurance. Rank C: Reached the maximum drive torque and stopped before 500 hours of endurance. Criteria for evaluating the condition of friction-affected components Rank A: No peeling at the end of 500 hours of durability. Rank B: At the end of durability testing, slight peeling occurred on the surface convex areas (less than 3% of the total). Rank C: At the end of durability testing, peeling was observed in the abrasion layer on the surface protrusions (more than 3% of the total surface area). Rank D: At the end of durability testing, peeling was observed in the surface convex areas where friction occurred (more than 10% of the total surface area). Also, every 100 hours, use A4-sized evaluation paper (Canon EN100 (64g / m²)). 2A melting unevenness evaluation image was printed across the entire surface of the image using cyan toner and magenta toner at 100% density, and the presence or absence of image defects was evaluated visually according to the following evaluation criteria. Evaluation Criteria Rank A: No image defects. Rank B: Minor image defects in a very small portion of the image. Rank C: Image malfunction detected during endurance test.

[0076] The evaluation results for each are shown in Table 1. The abraded member 304 obtained in Example 1 had thicknesses hA, hB, and hC of the abraded layer 304b of the surface protrusion 406. F hC R Because the layer was sufficiently thick, there was no increase in torque throughout the drive durability test. Furthermore, no peeling of the friction-resistant layer 304b was observed even after 500 hours of drive durability testing. In addition, there were no image defects, and the results were satisfactory.

[0077] [Table 1]

[0078] <Example 2> The abrasion-resistant member 304 was obtained in the same manner as in Example 1, except that the smoothing process was replaced with polishing. Compared to the smoothing process by pressing, the initial torque was lower, but a slight increase in torque was observed. However, it was still sufficiently low compared to the upper torque limit of 300 mNm, and the torque value, presence or absence of peeling, and presence or absence of image defects were all good results.

[0079] <Example 3> The abraded member 304 was obtained in the same manner as in Example 1, except that the thickness hA of the abraded layer 304b in the tip region of the surface protrusion 406 was set to 40 μm. Compared to Example 1, a slight increase in torque was observed in the latter half of the durability test, but it was still a sufficiently low value compared to the upper torque limit of 300 mNm, and the torque value, presence or absence of peeling, and presence or absence of image defects were all good results.

[0080] <Example 4> In the firing process of the abrasion-resistant layer 304b, the abrasion-resistant member 304 was obtained in the same manner as in Example 1, except that firing was performed without tilting. After durability testing, peeling of the abrasion-resistant layer 304b was observed at some surface protrusions 406, but this accounted for less than 3% of the total, and there was no impact on the torque value or image, indicating a good result.

[0081] <Example 5> The abraded member 304 was obtained in the same manner as in Example 2, except that the diameter d of the tip region 405a of the base material protrusion 405 was set to 150 μm, the firing was performed without tilting, and the thickness hA of the abraded layer 304b of the tip region of the surface protrusion 406 was set to 30 μm. Because the diameter d of the tip region 405a of the base material protrusion 405 was reduced, the torque was higher compared to Example 2, including the initial torque. Also, because the tip region of the surface protrusion 406 was small, stress concentrated in the tip region, and an increase in torque was confirmed throughout the durability test. After 500 hours of durability, the torque value exceeded 270 mNm, but it did not exceed the upper torque limit of 300 mNm. Regarding the tip region of the surface protrusion 406, peeling of the abraded layer 304b was confirmed in some tip regions of the surface protrusion 406, but it was less than 3% of the total, which was a good result.

[0082] <Example 6> The friction-resistant member 304 was obtained using the same process as in Example 4, except that the distance W between the centers of the base material protrusions 405 was 1140 μm and the rising angle θ of the base material protrusions 405 was 45°. Through durability testing, good results were obtained regarding torque value, presence or absence of peeling, and presence or absence of image defects.

[0083] <Example 7> The abraded member 304 was obtained using the same process as in Example 4, except that the height H1 of the base material protrusion 405 was set to 215 μm, the rising angle θ of the base material protrusion 405 was set to 80°, the distance W between the centers of the base material protrusion 405 was set to 1200 μm, and the diameter d of the tip region 405a of the base material protrusion 405 was set to 400 μm. The results regarding torque change and the presence or absence of peeling were good throughout the durability test. However, in the latter half of the durability test, minor image defects were observed in the image evaluation. This is thought to be because the height H of the surface protrusion 406 was low at 230 μm, causing wear debris to become embedded in the latter half of the durability test, resulting in minor pressure unevenness at the nip portion N between the fixing rotating body 301 and the abraded member 304.

[0084] <Comparative Example 1> A friction-to-abrasion member 304 was obtained by modifying the coating and firing processes as follows, using a base material 304a similar to the base material 304a prepared in Example 1.

[0085] (Formation of the abrasion layer) A dispersion of polyether ether ketone (PEEK) (product name: VICOTE® F817, manufactured by Victrex Corporation) was prepared. The viscosity of the paint was 63 mPa·s (23°C). Next, the substrate 304a prepared above was placed upright with the surface on which the substrate protrusions 405 were formed facing upwards, and the dispersion was applied from above using a spray gun (product name: W-101, manufactured by Anest Iwata Corporation) to form a coating film of the dispersion. Next, the substrate 304a with the coating film formed on it was placed in a heating furnace and heated at a temperature of 120°C for 5 minutes. After the coating film was dried, the substrate 304a was heated at a temperature of 400°C for 15 minutes to bake the coating film and form a first PEEK resin layer such that the thickness of the abrasion-scratched layer 304b on the tip region 405a of the substrate protrusions 405 was 10 μm.

[0086] The first PEEK resin layer prepared as described above was then coated with a dispersion of polyether ether ketone (PEEK) (product name: VICOTE® F804, manufactured by Victrex). The viscosity of the coating was 92 mPa·s (23°C). First, the substrate 304a prepared as described above was placed upright with the surface on which the substrate protrusions 405 were formed facing upwards, and the dispersion was applied from above using a spray gun (product name: W-101, manufactured by Anest Iwata Corporation) to form a coating film of the dispersion. Next, the substrate 304a with the coating film formed on it was placed in a heating furnace and heated at 120°C for 5 minutes to dry the coating film. After that, the surface on which the surface protrusions 406 were formed was placed upright in the heating furnace and heated at 400°C for 15 minutes to bake the coating film and form a second PEEK resin layer.

[0087] The thickness hA of the abrasion layer 304b on the surface protrusion 406 of the obtained abrasion member 304 was 30 μm, and the thickness hB of the abrasion layer 304b on the flat portion 407 was 45 μm.

[0088] A durability test was conducted on the obtained abrasion-resistant member 304 in the same manner as in Example 1. In Comparative Example 1, a torque increase was observed from the beginning of the durability test, and the durability test was stopped because it exceeded the upper limit of 300 mNm after 300 hours. Surface observation of the abrasion-resistant member 304 revealed that peeling of the abrasion-resistant layer 304b on more than 5% of the surface protrusions 406 was confirmed. This was because, during application and firing, the coating liquid flowed from the tip region 405a of the base material protrusions 405 to the flat portion 407, and in that process, the thickness hC of the edge region of the tip region of the surface protrusions 406 F hC R It is presumed that the thinning of the material made it more prone to peeling. As a result of increased peeling, the metal layer of the base material 304a was exposed, which is thought to have caused an increase in torque.

[0089] <Comparative Example 2> A friction-bearing member 304 was obtained using the same substrate 304a as that prepared in Example 1, following the same process as in Comparative Example 1. When forming the coating film, the coating conditions were modified so that the thickness hA of the friction-bearing layer 304b on the surface protrusions 406 was 60 μm.

[0090] A durability test was conducted on the obtained abrasion-resistant member 304 in the same manner as in Example 1. In Comparative Example 2, a torque increase was observed from the beginning of the durability test, and after 300 hours, it exceeded the upper limit of 300 mNm, so the durability test was stopped. Surface observation of the abrasion-resistant member 304 revealed that peeling of the abrasion-resistant layer 304b on more than 5% of the surface protrusions 406 was confirmed. This was because, during application and firing, the coating liquid flowed from the tip region 405a of the base material protrusions 405 to the flat portion 407, and in that process, the thickness hC of the edge region of the tip region of the surface protrusions 406 F hC R It is presumed that the thinning of the substrate made it more prone to peeling. The increased peeling exposed the metal layer of the base material 304a, which is thought to have resulted in an increase in torque. In addition, the increased thickness hB of the friction layer 304b in the flat section 407 resulted in a decrease in the height H of the surface protrusion 406, and around 300 hours in the latter half of the durability test, image defects were observed, which are thought to be caused by the inclusion of foreign matter such as wear particles. The test was stopped after 400 hours because the upper limit torque was reached.

[0091] <Comparative Example 3> The abraded member 304 was obtained by changing the height H1 of the base material protrusion 405 to 200 μm and following the same process as in Comparative Example 1. The abraded member 304 obtained in Comparative Example 3 had a low height H of the surface protrusion 406 from the beginning, and image defects were observed from the early stages of durability, after 100 hours. The test was stopped after 250 hours because the upper limit torque was reached.

[0092] <Comparative Example 4> The abraded member 304 was obtained by the same process as in Comparative Example 1, except that the rising angle θ of the base material protrusion 405 was increased to 85°. Because the base material protrusion 405 has a steep rising edge, coating liquid flow is likely to occur during the processing process, and in observation before the durability test, areas where the abraded layer 304b was absent were confirmed at the edges of the tip regions of several surface protrusions 406. In the durability test, the upper limit torque value was reached after 200 hours, so the test was stopped.

[0093] According to this disclosure, it is possible to provide a friction-resistant member 304, a fixing device 8, an image forming device 1, and a method for manufacturing the friction-resistant member 304 that can suppress image defects caused by poor foreign matter engagement and torque increases caused by peeling of the friction-resistant layer 304b, even during long-term durability.

[0094] According to one aspect of this disclosure, it is possible to provide a friction-bearing member 304 and a fixing device 8 that can suppress the exposure of the metal base material 304a and the peeling of the friction-bearing layer 304b due to wear of the friction-bearing layer 304b even during long-term use.

[0095] (Configuration 1) A friction-resistant member comprising a metal substrate having a surface provided with a plurality of substrate protrusions, and a friction-resistant layer covering the surface of the metal substrate provided with the plurality of substrate protrusions, wherein the height H of the surface protrusions formed by the substrate protrusions and the friction-resistant layer covering the substrate protrusions is 230 μm or more, the diameter d of the tip region of the substrate protrusions is 400 μm or less, the rising angle θ of the substrate protrusions is 35° to 80°, and any substrate protrusion is defined as substrate protrusion X, and the substrate protrusion X is the most A friction-resistant member characterized in that, when a nearby base material protrusion is called base material protrusion Y, the center-to-center distance W (mm) between the center of the base material protrusion X and the center of the base material protrusion Y is 1.2 or less, the height H1 of the base material protrusion, the diameter d, the rising angle θ, and the center-to-center distance W satisfy the relationship W × 1000 > d + 2 (H1 / tanθ), and the thickness hA of the friction-resistant layer in the tip region of the surface protrusion is greater than the thickness hB of the friction-resistant layer covering the portion between the base material protrusions. (Configuration 2) The friction-resistant member according to Configuration 1, characterized in that the portion between the base material protrusion and the base material protrusion is a flat portion. (Configuration 3) The abraded member according to Configuration 1 or 2, characterized in that the abraded layer is formed of resin. (Configuration 4) The thickness hC of the abrasion layer at one edge of the edge of the tip region of the protrusion of the base material F The abrasion member according to any one of configurations 1 to 3, characterized in that the thickness hA of the central part of the tip region of the base material protrusion is 30% or more. (Configuration 5) The thickness hC of the abrasion layer at one edge of the edge of the tip region of the protrusion of the base material F The thickness hC of the friction layer between the one edge and the other edge opposite to it. R A friction-to-abrasion member according to any one of the configurations 1 to 3, characterized in being larger than [a certain value]. (Configuration 6) The friction member according to any one of Configurations 1 to 5, characterized in that the tip region of the protrusion on the base material is substantially flat and circular in shape. (Configuration 7) A fixing device for fixing an unfixed toner image supported on a recording material to the recording material, comprising: a fixing rotating body; a pressing rotating body disposed opposite to the fixing rotating body and forming a nip together with the fixing rotating body; a friction-bearing member disposed inside the fixing rotating body and having a friction surface that can contact the inner circumferential surface of the fixing rotating body via a lubricant; a pressing member disposed inside the fixing rotating body and pressing the fixing rotating body against the pressing rotating body via the friction-bearing member; and a heater for heating the fixing rotating body, wherein the friction-bearing member is the friction-bearing member described in any one of Configurations 1 to 6, and the surface of the friction-bearing member on which the surface protrusion is provided is disposed opposite to the inner circumferential surface of the fixing rotating body. (Configuration 8) An image forming apparatus comprising an image forming unit that forms the unfixed toner image on the recording material, and a fixing device as described in Configuration 7. (Method 1) A manufacturing method for manufacturing a friction-to-abrasion member according to any one of the configurations 1 to 6, comprising: a coating step of spray-applying a coating agent containing a resin for forming the friction-to-abrasion layer to the surface of the metal substrate on which the plurality of substrate protrusions are provided; and a firing step of firing the resin contained in the coating agent applied to the surface to form a resin layer as the friction-to-abrasion layer, wherein the coating step includes a step of spray-applying the coating agent while rotating the metal substrate such that the centrifugal force at the tip region of the substrate protrusions is 1.5G or more and 3.0G or less in the direction of the tip of the substrate protrusions; and the firing step includes a step of heating the friction-to-abrasion member above the melting point of the resin constituting the resin layer while arranging the friction-to-abrasion member in a direction in which gravity acts towards the tip of the substrate protrusions, and then cooling the friction-to-abrasion member while keeping it in the orientation. (Method 2) A method for manufacturing a friction member according to Method 1, characterized in that after the firing step, a step is performed to smooth the tip region of the surface protrusion. [Explanation of Symbols]

[0096] 8. Fixing device 301 Rotating body for fixing 303 Pad (Backup component) 304 Abrasion-resistant member 304a base material 304b Rubbing layer 405 Base material protrusion 405a Tip area 406 Surface protrusions 407 Flat area H Height of surface protrusions H1 Height of the protrusion on the base material d Diameter of the tip region θ: Rising angle of the protrusion on the base material W Center distance hA Thickness of the abrasion layer in the tip region hB Thickness of the abrasion layer in the flat section

Claims

1. A metal substrate having a surface on which multiple substrate protrusions are provided, A friction-resistant layer covering the surface of the metal substrate on which the plurality of substrate protrusions are provided, A friction-to-abrasion member having, The height H of the surface protrusion formed by the substrate protrusion and the abrasion-resistant layer covering the substrate protrusion is 230 μm or more. The diameter d of the tip region of the protrusion on the substrate is 400 μm or less. The rising angle θ of the protrusion on the substrate is 35° to 80°. When any base material protrusion is denoted as base material protrusion X, and the base material protrusion closest to base material protrusion X is denoted as base material protrusion Y, the distance W (mm) between the centers of base material protrusion X and base material protrusion Y is 1.2 or less. The height H1 of the protrusion on the base material, the diameter d, the rising angle θ, and the distance between centers W satisfy the relationship W × 1000 > d + 2(H1 / tanθ), The thickness hA of the abrasion-resistant layer in the tip region of the surface protrusion is greater than the thickness hB of the abrasion-resistant layer covering the portion between the substrate protrusion and the substrate protrusion. A friction-resistant member characterized by the following features.

2. The friction-resistant member according to claim 1, characterized in that the portion between the base material protrusion and the base material protrusion is a flat portion.

3. The abraded member according to claim 1, characterized in that the abraded layer is formed of resin.

4. The thickness h of the abrasion layer at one edge of the edge of the tip region of the protrusion of the substrate. Ｆ The abrasion member according to claim 1, characterized in that the thickness hA of the central part of the tip region of the base material protrusion is 30% or more.

5. The thickness h of the abrasion layer at one edge of the edge of the tip region of the protrusion of the substrate. Ｆ The thickness hC of the friction layer between the one edge and the other edge opposite to it. Ｒ The abrasion member according to claim 1, characterized in that it is larger than [the specified size].

6. The abrasion member according to claim 1, characterized in that the tip region of the protrusion on the base material is substantially flat and circular in shape.

7. A fixing device for fixing an unfixed toner image supported on a recording material to the recording material, A rotating body for fixing, A pressing rotating body is positioned opposite the fixing rotating body and together with the fixing rotating body forms a nip portion, A member to be abraded, which is positioned inside the fixing rotating body and has a sliding surface that can contact the inner circumferential surface of the fixing rotating body via a lubricant, A pressing member is positioned inside the fixing rotating body and presses the fixing rotating body against the pressing rotating body via the friction-bearing member, A heater for heating the aforementioned rotating fixing body, Equipped with, The abraded member is the abraded member according to any one of claims 1 to 6, A fixing device characterized in that the surface of the abrasion member on which the surface protrusion is provided is arranged opposite the inner circumferential surface of the fixing rotating body.

8. The recording material includes an image forming unit that forms the unfixed toner image, The fixing device according to claim 7, An image forming apparatus characterized by comprising:

9. A manufacturing method for producing a friction-to-abrasion member according to any one of claims 1 to 6, A coating step of spray-applying a coating agent containing a resin for forming the abrasion-resistant layer to the surface of the metal substrate on which the plurality of substrate protrusions are provided, A firing step in which the resin contained in the coating agent applied to the surface is fired to form a resin layer as the abrasion layer, Includes, The coating step includes a step of spraying the coating agent while rotating the metal substrate such that the centrifugal force at the tip region of the substrate protrusion is 1.5G or more and 3.0G or less in the direction of the substrate protrusion. The firing process includes heating the abrasion member to a temperature above the melting point of the resin constituting the resin layer, while positioning the abrasion member in a orientation where gravity acts toward the tip of the protrusion on the base material, and then cooling the abrasion member while keeping it in the orientation. A method for manufacturing a friction-to-abrasion member, characterized by the above.

10. The method for manufacturing a friction member according to claim 9, characterized in that, after the firing step, a step of performing a smoothing treatment on the tip region of the surface protrusions.

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