Sliding member for fixation and fixation device

Abstract

To provide a sliding member for fixation which can reduce initial driving torque and keep a high quality at the same time.SOLUTION: The sliding member for fixation includes: a metal base material with a plurality of first protruding parts in at least one surface; a resin layer for covering the surface of the first protruding parts of the metal base material; a plurality of second protruding parts corresponding to the first protruding parts, located in the side opposite to the side of the resin layer which faces the metal base material. At least one of the second protruding parts has at least one recessed part in the top. An edge part surrounding the at least one recessed part is in contact with a glass plate when the glass plate is pressed at 0.4 Mpa against the surface with the second protruding parts of the sliding member for fixation at the temperature of 25°C.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a sliding member for a fixing device and a fixing device.

Background Art

[0002] In recent years, the on-demand printing market has been expanding, in which commercial printed materials such as catalogs, posters, and pamphlets are printed according to the required number of copies, and various invoices, direct mail, etc. are continuously printed while partially changing the printed content for each customer. These days, electrophotographic image forming apparatuses for on-demand printing are required to achieve even higher printing speeds. In order to achieve an even higher printing speed, it is necessary to apply sufficient energy to an unfixed toner image on a recording material such as paper in a short time to fix the unfixed toner image to the recording material. As one method therefor, use of a fixing device having a wide fixing nip that can apply energy to the unfixed toner image for a relatively long time can be mentioned. Here, the width of the fixing nip refers to the length of the contact portion between the fixing rotating body for heating the unfixed toner image and the pressurizing rotating body disposed opposite to the fixing rotating body in the direction along the conveyance direction of the recording medium. Hereinafter, a fixing device having a wide fixing nip may also be referred to as a fixing device with a wide nip. In such a fixing device with a wide nip, in order to ensure excellent image quality, it is crucial to more surely prevent slip between the fixing rotating body and the recording medium, and slip between the pressurizing rotating body and the recording medium.

[0003] Further, as the fixing device, (i) an endless rotatable belt (fixing rotating body), (ii) a pressurizing member that forms a nip portion for sandwiching and conveying the recording medium between the belt, (iii) a sliding member that slides on the inner peripheral surface of the belt via a lubricant in the nip portion, An apparatus equipped with [the lubricant] is known. The lubricant is used for the purpose of stabilizing the sliding between the inner surface of the belt and the sliding member. When the lubricant no longer exists in the nip portion, the rotation of the belt becomes unstable, wear occurs on the inner surface of the belt and the sliding member, and the life of the apparatus is shortened. In such a fixing device, in order to suppress the above-mentioned slip, it is necessary to make the sliding resistance between the sliding member and the inner peripheral surface of the belt member sufficiently smaller than the frictional force between the recording medium and the belt member and the frictional force between the recording medium and the pressing member. In Patent Document 1, in the configuration of the fixing device as described above, it has a base material layer formed with a plurality of protrusions protruding toward the inner peripheral surface of the belt on the side that slides with the belt, and a sliding layer provided so as to cover the surface of the base material layer on the side that slides with the belt. Among the sliding layers, the shape of the surface of the sliding layer formed at the tip portions of the plurality of protrusions is a curved surface with a radius of curvature R of 300 to 850 μm, and it is disclosed that a sliding member is used. And in Patent Document 1, it is said that by using the sliding member as described above, the sliding resistance between the sliding member and the inner peripheral surface of the belt can be reduced.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Non-Patent Documents

[0005]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] According to the study by the present inventors, the fixing device according to Patent Document 1 was effective in reducing the sliding resistance between the sliding member and the inner peripheral surface of the belt member to a certain extent. However, when starting the drive (rotation) of the rotating member for fixing in a stationary state, the sliding resistance between the sliding member and the inner peripheral surface of the belt member increases, and slippage may occur between the rotating member for fixing and the recording medium, as well as between the rotating member for pressing and the recording medium. Also, due to the increase in the sliding resistance, the initial drive torque of the fixing device for starting the rotation of the rotating member for fixing in a stationary state tended to increase. At least one aspect of the present disclosure is directed to providing a fixing sliding member having a small sliding resistance with respect to the inner peripheral surface of the rotating member for fixing even at the start of driving the rotating member for fixing in a stationary state. Also, at least one aspect of the present disclosure is directed to providing a fixing device having a small initial drive torque when starting the drive of the rotating member for fixing in a stationary state.

Means for Solving the Problems

[0007] According to at least one aspect of the present disclosure, a fixing sliding member, comprising: a metal base material having a plurality of first convex portions on at least one surface; and a resin layer covering the surface of the first convex portions of the metal base material, wherein on a side of a surface of the resin layer opposite to a side facing the metal base material, there are a plurality of second convex portions corresponding to the plurality of first convex portions, and at least one of the plurality of second convex portions has at least one concave portion at its top, and when a glass plate is pressed against a surface of the fixing sliding member having the plurality of second convex portions at a temperature of 25°C with a pressure of 0.4 MPa, a fixing sliding member is provided in which an edge portion surrounding the concave portion comes into contact with the glass plate. Also, according to at least one aspect of the present disclosure, there is provided a fixing device for fixing an unfixed toner image carried on a recording material to the recording material, the fixing device including a rotating member for fixing, a pressing rotating member disposed opposite to the rotating member for fixing and forming a nip portion together with the rotating member for fixing, a sliding member disposed inside the rotating member for fixing and having a sliding surface slidable with respect to the inner peripheral surface of the rotating member for fixing via a lubricant, a backup member disposed inside the rotating member for fixing and sandwiching the sliding member and the rotating member for fixing between the backup member and the pressing rotating member to backup the sliding member, and a heater for heating the rotating member for fixing, wherein the sliding member is the above-described sliding member for fixing, and the surface of the sliding member for fixing having a plurality of second convex portions is disposed so as to face the inner peripheral surface of the rotating member for fixing.

Advantages of the Invention

[0008] According to at least one aspect of the present disclosure, it is possible to obtain a fixing sliding member having a small sliding resistance with respect to the inner peripheral surface of the fixing rotating member even at the start of driving of the fixing rotating member in a stationary state. Further, according to at least one aspect of the present disclosure, it is possible to obtain a fixing device having a small initial driving torque when starting to drive the fixing rotating member in a stationary state.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Mode for Carrying Out the Invention

[0010] In this specification, descriptions such as "XX or more and YY or less" and "XX to YY" representing numerical ranges mean numerical ranges including the lower limit and the upper limit which are endpoints, unless otherwise specified. Also, when numerical ranges are described stepwise, the upper limit and the lower limit of each numerical range can be arbitrarily combined. In the present disclosure, for example, a description such as "at least one selected from the group consisting of XX, YY, and ZZ" means any one 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.

[0011] Normally, a lubricant such as grease is interposed between the inner peripheral surface of the fixing rotating body and the sliding surface of the sliding member in order to impart good slidability. However, when starting the drive of the fixing rotating body in a stationary state, the lubricant may be extruded from the contact portion between the inner peripheral surface of the fixing rotating body and the sliding surface of the sliding member due to physical impact during driving or the like. Because of this, it is considered that the sliding resistance between the sliding surface of the sliding member and the inner peripheral surface of the fixing rotating body becomes extremely large. Therefore, as a result of further investigations by the present inventors, according to a fixing sliding member having the following configuration, even at the start of driving of the fixing rotating body, a lubricant can be surely present at the contact portion between the sliding member and the inner peripheral surface of the fixing belt. As a result, an increase in the sliding resistance between the sliding surface of the sliding member and the inner peripheral surface of the fixing rotating body can be prevented, and from the initial stage of image formation, slip between the fixing rotating body and the recording medium, as well as slip between the pressing rotating body and the recording medium can be suppressed. In addition, it has been found that an increase in the initial drive torque can be suppressed.

[0012] <Configuration> A fixing sliding member having a metal base material having a plurality of first convex portions on at least one surface thereof, and a resin layer covering the surface of the first convex portions of the metal base material, wherein on the side of the surface of the resin layer opposite to the side facing the metal base material, there are a plurality of second convex portions corresponding to the plurality of first convex portions, and at least one of the plurality of second convex portions has at least one concave portion at its top, and when a glass plate is pressed against the surface of the fixing sliding member having the second convex portions at a temperature of 25°C with a pressure of 0.4 MPa, the edge portion surrounding the concave portion contacts the glass plate.

[0013] Hereinafter, an aspect of the fixing sliding member according to the present disclosure and an aspect of the fixing device according to the present disclosure will be described with reference to the drawings.

[0014] FIGS. 2 and 3 are schematic cross-sectional views for explaining a fixing device 300 according to an aspect of the present disclosure. In FIG. 2, the X direction is the conveyance direction of a recording material (not shown), the Y direction is the direction intersecting the conveyance direction of the recording material (the depth direction of the paper surface), and the Z direction is the pressing direction in which the recording material is pressed at the nip portion N. In the present embodiment, the X direction, the Y direction, and the Z direction are directions orthogonal to each other. Further, FIG. 3 is an enlarged cross-sectional view of a region NA including the nip portion N surrounded by a dotted line in FIG. 2.

[0015] The fixing device 300 includes at least a fixing rotating body 301, a pressure stay 302, a pressure pad (hereinafter also simply referred to as "pad") 303, a sliding member 304, a pressure applying rotating body 305, a heater 306, a heating roller 307, and a thermistor 308. The fixing rotating body 301 can be, for example, a belt having an endless shape. Further, the pressure applying rotating body 305 abuts against the outer peripheral surface of the fixing rotating body 301 to form a nip portion N for sandwiching and conveying the recording material between the fixing rotating body 301 and itself. It holds and conveys.

[0016] The sliding member 304 slides on the inner peripheral surface of the fixing rotating body 301 at the nip portion N. The pad 303 as a backup member is disposed inside the fixing rotating body 301 so as to sandwich the sliding member 304 and the fixing rotating body 301 between itself and the pressure applying rotating body 305, and backs up the sliding member 304. The sliding member 304 is disposed so as to cover the surface (hereinafter also referred to as "outer surface") of the pad 303 facing the fixing rotating body 301. The sliding member 304 is attached so as to cover at least the position corresponding to the nip portion N of the outer surface of the pad 303. Note that the sliding member 304 may be provided on the entire outer surface of the pad 303, or may be attached only at the position corresponding to the nip portion N.

[0017] The pressure stay 302 is disposed inside the fixing rotating body 301 on the side opposite to the nip portion N with the pad 303 interposed therebetween, and supports the pad 303. The heating roller 307 is disposed inside the fixing rotating body 301 so as to stretch the fixing rotating body 301, and heats the fixing rotating body 301. The thermistor 308 as a temperature detecting member detects the temperature of the fixing rotating body 301.

[0018] The fixing rotating body 301 has thermal conductivity, heat resistance, etc., and has a thin cylindrical shape. In this embodiment, as shown in FIG. 2B, the fixing rotating body 301 has a base layer 301a, an elastic layer 301b covering the outer peripheral surface of the base layer 301a, and a release layer 301c covering the outer peripheral 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. Also, the release layer 301c can be, for example, a fluororesin layer with a thickness of 30 μm. Examples of fluororesins include, for example, tetrafluoroethylene·perfluoroalkoxyethylene copolymer resin (PFA) and FEP. The fixing rotating body 301 is stretched by the pad 303 and the heating roller 307. The outer diameter of the fixing rotating body 301 can be, for example, 150 mm.

[0019] The pad 303 is arranged inside the fixing rotating body 301 so as to face the pressing rotating body 305 with the fixing rotating body 301 interposed therebetween, and forms a nip portion N for sandwiching and conveying the recording material between the fixing rotating body 301 and the pressing rotating body 305. 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 of the fixing rotating body 301, the rotation axis direction of the heating roller 307). When the pad 303 is pressed against the pressing rotating body 305 with the fixing rotating body 301 interposed therebetween, the nip portion N is formed. As the material of the pad 303, for example, an LCP (liquid crystal polymer) resin can be used. A sliding member 304 is interposed between the pad 303 and the fixing rotating body 301. Details of the sliding member 304 will be described later.

[0020] Pad 303 is supported by stay 302 as a support member disposed inside fixing rotator 301. Stay 302 is disposed on the side opposite to pressure-applying rotator 305 of pad 303 and supports pad 303. Stay 302 is a reinforcing member having long rigidity along the longitudinal direction of fixing rotator 301, abuts against pad 303, and backs up pad 303. That is, stay 302 gives strength to pad 303 when pad 303 is pressed by pressure-applying rotator 305 to ensure the pressure in nip portion N.

[0021] Stay 302 is made of metal such as stainless steel, for example, and has a substantially rectangular cross-section (transverse cross-section) orthogonal to the longitudinal direction of stay 302 intersecting the rotation direction of fixing rotator 301. For example, stay 302 is preferably formed into a hollow shape with a substantially U-shaped cross-section using a drawn material of stainless steel (for example, SUS304, etc.) with a wall thickness of 3 mm to ensure strength. Note that stay 302 may be formed into a substantially rectangular cross-section by combining a plurality of sheet metals and fixing them to each other by welding or the like. Also, the material of stay 302 is not limited to stainless steel as long as its strength can be ensured.

[0022] Heating roller 307 is disposed inside fixing rotator 301 and stretches fixing rotator 301 together with pad 303. Heating roller 307 is a cylindrical member formed of metal such as aluminum or stainless steel, for example, and a heater 306 for heating fixing rotator 301 is disposed inside thereof. Heater 306 only needs to be able to heat heating roller 307, and examples thereof include a halogen heater and a carbon heater. Heating roller 307 is heated to a predetermined temperature by heater 306.

[0023] The heating roller 307 has a rotation center at one end in the longitudinal direction or near the center, and rotates with respect to the fixing rotator 301 to generate a tension difference before and after, and is also a steering roller that controls the position of the fixing rotator 301 in the main scanning direction. Further, the heating roller 307 is biased by a spring supported by a frame (not shown), and is also a tension roller that applies a predetermined tension to the fixing rotator 301.

[0024] In the present embodiment, the heating roller 307 is formed of, for example, a stainless steel pipe with a thickness of 1 mm. Also, when a halogen heater is used as the heater 306, the number of halogen heaters may be one, but in view of controlling the temperature distribution in the longitudinal direction (the direction of the rotation axis direction) of the heating roller 307, it is desirable to use a plurality of them. The plurality of halogen heaters have different light distribution distributions in the longitudinal direction, and the lighting ratio is controlled according to the size of the recording material. In the present embodiment, three halogen heaters are arranged as the heater 306.

[0025] The fixing rotator 301 is heated by the heating roller 307 heated by the heater 306, and is controlled to a predetermined target temperature according to the type of the recording material based on the temperature detected by the thermistor 308. The thermistor 308 is arranged to face the outer peripheral surface of the fixing rotator 301 near the center where the recording materials of all sizes that can be fixed by the fixing device 300 pass in the width direction of the fixing rotator 301. Then, the thermistor 308 detects the temperature of the fixing rotator 301, and the control unit 30 controls the power supplied to the heater 306 so that the detected temperature of the thermistor 308 becomes the target temperature. Note that the thermistor 308 may be a non-contact type sensor arranged close to the outer peripheral surface of the fixing rotator 301, or a contact type sensor arranged in contact with the outer peripheral surface of the fixing rotator 301.

[0026] ​​The rotating body 305 for pressing is also a driving roller that contacts and rotates on the outer peripheral surface of the fixing rotating body 301 and applies a driving force to the fixing rotating body 301. Note that the heating roller 307 can also be used as the driving roller of the fixing rotating body 301 by driving it with a driving source (not shown) such as a motor. That is, the driving roller of the fixing rotating body 301 can be at least one selected from the group consisting of the pressing rotating body 305 and the heating roller 307. The pressing rotating body 305 has, for example, a core metal (shaft) 305c, an elastic layer 305b provided on the outer periphery of the core metal 305c, and a release layer 305a covering the outer periphery thereof. As the core metal 305c, for example, a stainless steel roller with a diameter of 72 mm can be used. The elastic layer 305b can be, for example, a conductive elastic layer containing silicone rubber with a thickness of 8 mm. Further, the release layer 305a can be, for example, a fluororesin layer with a thickness of 100 μm. Examples of fluororesins include, for example, tetrafluoroethylene-perfluoroalkoxyethylene copolymer resin (PFA). The pressing rotating body 305 is rotatably supported by a frame (not shown) of the fixing device 300, and a gear (not shown) is fixed to one end, and it is connected to a driving source (not shown) such as a motor through the gear and driven.

[0027] In the fixing device 300, in the nip portion N formed between the fixing rotating body 301 and the pressing rotating body 305, the recording material P carrying the unfixed toner image is sandwiched and the unfixed toner image is heated while being conveyed. Thus, the fixing device 300 fixes the toner to the recording material P while sandwiching and conveying the recording material P. Therefore, it is necessary to achieve both the function of applying heat and pressure and the function of conveying the recording material P. By a driving source (not shown), the pressing rotating body 305 is pressed against the sliding member 304 via the fixing rotating body 301. In this embodiment, the pressing force (NF) in the nip portion N during image formation, that is, the load value applied to the pad 303 and the pressing rotating body 305 is 1600 N, and the width of the nip portion N in the X direction (the conveying direction of the recording material) is 24.5 mm, and the width in the Y direction (the width direction of the recording material) is set to 326 mm.

[0028] Note that the length (nip width) of the nip portion N in the conveyance direction (X direction) is formed by pressing the sliding member 304 against the pressurizing rotating body 305 via the fixing rotating body 301. The pressing force (F1) in the nip portion N is not particularly limited, but it is preferable to apply a force sufficient to press the fixing rotating body 301 with the pressing force of the pressurizing rotating body so that no slip occurs between the recording material P passing through the nip portion N, the fixing rotating body, and the pressurizing rotating body. As an example, for instance, it is preferable to set the load value applied to the pad 303 and the pressurizing rotating body 305 to be 900 N or more, particularly 1600 N or more.

[0029] [Sliding member] The sliding member 304 will be described with reference to FIGS. 3 and 4. FIG. 3 is an enlarged cross-sectional view of the region NA including the nip portion N, which is surrounded by a dotted line in FIG. 2. FIG. 4 is a partially enlarged view of the sliding member 304. Here, the sliding member 304 is fixed to the stay 302 via the pad 303 with screws (not shown). In this embodiment, the sliding member 304 and the pad 303 are separate members, but they may be integrated.

[0030] The sliding member 304 includes a base material 304a having a plurality of first convex portions 405 on one surface, and a resin layer 304b covering the surface of the base material 304a on the side where the first convex portions 405 are formed. The resin layer 304b has a plurality of second convex portions 407 corresponding to the plurality of first convex portions 405. The second convex portion 407 has at least one concave portion 408 at its top, that is, the portion closest to the inner peripheral surface of the fixing rotating body 301 of the second convex portion 407.

[0031] Further, the sliding member 304 satisfies the following requirement 1. <Requirement 1> In an environment with a temperature of 25°C, as shown in FIG. 4B, a transparent glass plate 411 is placed facing the surface of the sliding member 304 on the side where the second convex portion 407 is provided, and a force is applied to the back surface of the base material 304a of the sliding member 304, that is, the surface on the side opposite to the side where the first convex portion 405 is provided, in the direction of arrow F2 so that the pressure becomes 0.4 MPa, and the sliding member 304 is pressed against the glass plate 411. While maintaining this state, observe the glass plate 411 and the sliding member 304 from the side opposite to the side of the glass plate 411 facing the sliding member 304. At this time, the edge portion 413 surrounding the recess 408 existing at the top of the second convex portion 407 comes into contact with the glass plate 411. Here, the method of the above observation is not particularly limited. For example, it can be observed using a digital microscope or the like. At this time, it can be confirmed that the edge portion 413 surrounding the recess 408 existing at the top of the second convex portion 407 is in contact with the glass plate 411. As a more specific confirmation method, for example, an image of the contact state between the glass plate and the sliding member is acquired using a digital microscope. Using image processing software or the like, a binary image in which the contact portion and the non-contact portion can be discriminated is created from the obtained image. From this binary image, it can be confirmed that the edge portion 413 surrounding the recess 408 existing at the top of the second convex portion 407 is in contact with the glass plate 411. Note that for binarization, for example, the "Otsu method" described in Non-Patent Document 1 can be used.

[0032] <substrate> The base material 304a preferably has sufficient strength so that no deformation or the like occurs even when a pressing force of the fixing rotating body 301 against the pressing rotating body 305 is applied, and heat resistance. Therefore, as the material of the base material 304a, a metal is preferable, and specifically, for example, stainless steel, aluminum, aluminum alloy, nickel, nickel alloy, etc. can be mentioned. Specifically, for example, stainless steel (for example, SUS304, etc.) with a thickness of 1.3 mm can be used. Here, the thickness of the base layer refers to the thickness of the portion where the first convex portion 405 is not provided.

[0033] ​The plurality of first convex portions 405 constitute a part of the base material 304a. From the viewpoint of equalizing the pressure in the nip portion N, it is preferable that a plurality of the first convex portions 405 are arranged in a direction along the conveyance direction (X direction) of the recording material in the nip portion N and in a direction along the direction intersecting the conveyance direction (Y direction), respectively.

[0034] The shape of each of the plurality of first convex portions 405 is preferably a frustum shape. The frustum shape is not particularly limited as long as it can hold a sufficient amount of lubricant to contribute to reducing the starting torque of the fixing device, but it is preferable that the diameter of the bottom surface is larger than the diameter of the upper surface. Also, the height is not particularly defined, but is preferably 100 μm or more in order to hold a sufficient amount of lubricant as well. The angle of the hypotenuse is not particularly defined, but is preferably 30° or more. The manufacturing method of the base material 304a having a plurality of first convex portions is not particularly limited, and examples thereof include chemical etching and press working.

[0035] <Resin layer> The resin layer 304b covers the surface of the base material 304a on the side where the plurality of first convex portions 405 are present. And on the surface of the resin layer 304b on the side opposite to the side facing the base material 304a (hereinafter, also referred to as the "outer surface"), there are second convex portions 407 corresponding to the plurality of first convex portions 405. Here, the second convex portion 407 corresponding to the first convex portion 405 refers to a convex portion formed on the outer surface of the resin layer 304b by covering the surface of the first convex portion 405.

[0036] The plurality of second convex portions 407 existing on the surface of the resin layer 304b facing the inner peripheral surface of the fixing rotating body 301 of the sliding member 304 configured by the outer surface of the resin layer 304b can reduce the contact area between the sliding member 304 and the inner peripheral surface of the fixing rotating body 301, and can reduce the sliding resistance between the sliding member 304 and the inner peripheral surface of the fixing rotating body 301. Furthermore, by satisfying the above requirements, the sliding member 304 can stably have a lubricant present at the contact portion between the second convex portion 407 and the inner peripheral surface of the fixing rotator 301 even when the sliding member 304 is pressed against the inner peripheral surface of the fixing rotator 301 in the fixing device in a stationary state. As a result, an increase in the starting torque of the fixing device can be prevented.

[0037] The material constituting the resin layer is not particularly limited, but a resin having excellent wear resistance and excellent slidability with the inner peripheral surface of the fixing rotator 301 is preferable. Specifically, for example, polyetheretherketone (PEEK) can be mentioned.

[0038] The recess 408 becomes a region where a lubricant that exhibits the effect of reducing the starting torque is present. Therefore, the depth 501 of the recess is not particularly limited as long as a lubricant can be present, but for example, it is preferably 1.0 μm or more, particularly preferably 1.5 μm or more, and even more preferably 4.0 μm or more. The upper limit of the depth of the recess is not particularly limited as long as, in the fixing device, in a state where the sliding member is in contact with the inner peripheral surface of the fixing rotator, a recess capable of holding a lubricant can exist at the top of the second convex portion. For example, it is preferably 10.0 μm or less, particularly preferably 6.0 μm or less. This is preferable. Therefore, a preferable range for the depth of the recess 408 is, for example, 1.0 to 10.0 μm, particularly 1.0 to 6.0 μm. The depth of the recess 408 can be measured, for example, by a method of extracting a two-dimensional height profile measured using a three-dimensional shape measuring machine. As the three-dimensional shape measuring instrument, for example, "One Shot 3D Shape Measuring Machine VR-3200" (trade name, manufactured by Keyence Corporation) or the like can be used.

[0039] Further, the equivalent diameter 503 of the area of the recess 408 surrounded by the edge portion 413 is not particularly limited as long as the recess 408 can hold a sufficient amount of lubricant to contribute to reducing the starting torque of the fixing device. For example, it is preferably in the range of 20 to 600 μm, particularly preferably in the range of 50 to 500 μm, and even more preferably in the range of 80 to 450 μm.

[0040] A plurality of second convex portions 407 are arranged in plurality in the conveying direction (X direction) of the recording material P in the nip portion N and also in the direction (Y direction) intersecting the X direction. Specifically, for example, as defined in the above requirements, when a pressure of 0.4 MPa is applied to press the outer surface of the sliding member 304 against the glass plate 411, FIG. 6 shows one aspect of the contact state between the glass plate 411 and the sliding member 304 when observing the sliding member from the side opposite to the side of the glass plate 411 facing the sliding member. As shown in FIG. 6, a plurality of edge portions 413 surrounding the recess 408 are observed in the X direction and the Y direction, respectively. The number of the edge portions 413 observed at this time is not particularly limited. For example, when a square observation region with a side length of 1 cm is set on the glass plate 411, the number of the edge portions 413 surrounding the recess 408 observed within the square observation region is preferably 50 to 500, particularly preferably 75 to 400, and even more preferably 100 to 200. Further, the ratio of the total area of the regions (hereinafter also referred to as "surrounding regions") surrounded by the outermost lines of the edge portions 413 surrounding the recess 408 to the area of the observation region is preferably 5 to 80%, particularly preferably 10 to 60%, and even more preferably 15 to 40%.

[0041] <Method for manufacturing a sliding member> As a method for manufacturing the sliding member according to the present disclosure, for example, a method having the following steps A to C can be mentioned.

[0042] Step A: Prepare a base material 304a having a first convex portion 405 on the surface of one side. As described above, such a base material can be manufactured, for example, by chemical etching or press working.

[0043] Process B: On the surface of the base material 304a prepared in Process A on the side where the first convex portion 405 is formed, a resin layer (701 in Fig. 7A) is formed. The method for forming the resin layer is not particularly limited, and for example, the following methods (i) to (ii) can be mentioned. Method (i): A method of forming a resin layer 701 by applying a resin solution obtained by dissolving the resin constituting the resin layer 304b in an appropriate solvent onto the surface to form a coating film of the resin solution, and then drying the coating film. Method (ii): A method of forming a resin layer 701 by applying a dispersion of the resin constituting the resin layer 304b onto the surface to form a coating film of the dispersion, and then drying and firing the coating film. In Process B, the thickness L-701 of the portion of the resin layer 701 other than the first convex portion 405 of the base material 304a is not particularly limited, but on the outer surface of the resin layer 701, a convex portion (second convex portion) corresponding to the first convex portion 4 05 on the base material 304a is preferably formed to have a thickness such that. Specifically, for example, the thickness L-701 of the resin layer 701 is preferably smaller than the height (H -405) of the first convex portion 405, that is, it is preferably H-405>L-701. . Further, it is preferable that the resin layer 701 completely covers the first convex portion of the base material 304a. Furthermore, the maximum thickness (L-703) of the resin layer covering the first convex portion 405 is preferably, for example, 5 to 100 μm, particularly preferably 10 to 50 μm, in order to make it easier to form the concave portion 408 at the top of the second convex portion. Note that L-701 and L-703 may be the same or different.

[0044] Process C: A concave portion 408 is formed at the top of the second convex portion formed corresponding to the first convex portion of the resin layer 701 to form the resin layer 304b according to the present disclosure. In Project C, as a method of forming a concave portion at the top of the second convex portion, for example, as shown in FIG. 7B, a press plate 703 is pressed against the resin layer 701 at the top of the second convex portion 407 with a predetermined pressure, and heat treatment is performed in a temperature range that is equal to or higher than the glass transition temperature and lower than the melting point of the resin constituting the resin layer, particularly in a temperature range that is equal to or higher than the glass transition temperature + 10°C and lower than the melting point. One reason why a concave portion is formed at the top of the second convex portion by this method is considered as follows. By applying pressure to the top of the second convex portion at the above temperature, the resin layer moves, and the second convex portion is smoothed and has a diameter larger than that of the first convex portion. Then, when the pressure is released, since the resin layer has a lower elastic modulus than the base material, in the second convex portion having a diameter larger than that of the first convex portion, a concave portion is formed because the elastic deformation amount in the height direction is large.

[0045] Specifically, for example, when the resin layer 701 is made of polyetheretherketone (PEEK; glass transition temperature: 143°C, melting point: 343°C) and has a storage elastic modulus of 0.2 GPa at 25°C, and the maximum thickness L-703 of the second convex portion is 30 μm, by pressing a press plate against the top of the second convex portion with a pressure of 4 MPa and performing heat treatment at a temperature of 200°C for 10 minutes, a concave portion with a depth 501 of 2 μm can be formed at the top of the second convex portion.

[0046] The depth 501 of the concave portion can be increased (made deeper), for example, by forming the resin layer with a resin having a high elastic modulus at the press temperature.

[0047] In the sliding member according to the present disclosure, it is preferable that the elastic modulus (storage elastic modulus) E´(200) of the resin layer 304b at a temperature of 200°C is at least one digit lower than the elastic modulus (storage elastic modulus) E´(25) at a temperature of 25°C. In particular, it is preferable that E´(25) is 2.5 to 4.0 GPa and E´(200) is 0.06 to 0.13 times E´(25).

[0048] By controlling the elastic modulus of the sliding member as described above, at a temperature of 25°C, the depth of the concave portion 408 at the top of the second convex portion can be sufficiently ensured. On the other hand, at 200°C near the fixing temperature of the unfixed toner image, the elastic modulus of the resin layer decreases, and the elastic layer of the sliding member 304 elastically deforms due to the pressing force on the inner peripheral surface of the fixing rotating body 301. Therefore, the depth of the concave portion 408 becomes shallower. When the fixing device is operating and the fixing rotating body 301 is rotating stably, since a lubricant layer is stably formed between the sliding surface of the sliding member 304 and the inner peripheral surface of the fixing rotating body, the presence of the concave portion 408 at the top of the second convex portion is not necessarily required. Rather, in the heat fixing process, by increasing the contact area between the edge portion 413 surrounding the concave portion 408 and the inner peripheral surface of the fixing rotating body, the nip pressure applied to the unfixed toner image can be made more uniform. Therefore, a higher-quality image can be formed. Such a resin layer 304b can be obtained, for example, by using PEEK as the constituent material of the resin layer 304b. The resin layer 304b made of PEEK depicts a profile as shown in FIG. 8 for the storage elastic modulus measured on its outer surface. Specifically, while E´(25) is 3.3 GPa, E´(200) is 0.2 GPa, which is one digit lower. And thus, at a temperature of 25°C, it has a concave portion at the top of the second convex portion, and at a temperature of 200°C, the contact area with the inner peripheral surface of the fixing rotating body of the edge portion surrounding the concave portion is relatively increased such that the sliding member can satisfy the reduction of the starting torque and the formation of a high-quality electrophotographic image at a higher level.

[0049] Such a sliding member can satisfy the following requirements (2-i) to (2-iii). <Requirement 2-i> When a glass plate is pressed on the surface having the second convex portion of the fixing sliding member at a pressure of 0.4 MPa at a temperature of 25°C, the edge portion surrounding the concave portion contacts the glass plate. <Requirement 2-ii> When a glass plate is pressed against the surface of the fixing sliding member having the second convex portion at a temperature of 200°C with a pressure of 0.4 MPa, the edge surrounding the concave portion comes into contact with the glass plate. <Requirement 2-iii> When the average value of the contact area ratio represented by the following calculation formula (1) at a temperature of 25°C is A25, and the average value of the contact area ratio represented by the following calculation formula (2) at a temperature of 200°C is A200, A25 < A200: [x1 / (x1 + y1)]×100 (1) In the calculation formula (1), x1 represents the area of the edge in contact with the glass plate at a temperature of 25°C, y1 represents the projected area of the concave portion surrounded by the edge on the glass plate at a temperature of 25°C. [x2 / (x2 + y2)]×100 (2) In the calculation formula (2), x2 represents the area of the edge in contact with the glass plate at a temperature of 200°C, y2 represents the projected area of the concave portion surrounded by the edge on the glass plate at a temperature of 200°C.

[0050] At this time, A200 is preferably at least twice A25. And on the premise that A25 < A200, A200 is preferably 30% or more and 85% or less, and particularly preferably 40% or more and 85% or less. Also, on the premise that A25 < A200, A25 is preferably 10% or more and 50% or less.

[0051] <Image forming apparatus> Hereinafter, an electrophotographic image forming apparatus (hereinafter also referred to as an "image forming apparatus") according to an aspect of the present disclosure will be described with reference to FIG. 1. In the following, an image forming apparatus capable of forming a color image having a plurality of electrophotographic photosensitive drums will be described as an example, but the present disclosure is not limited thereto and can also be applied to a monochromatic image forming apparatus or the like. The full-color image forming apparatus 1 includes an image reading unit 2 and the main body 3 of the image forming apparatus. The image reading unit 2 reads a document placed on the document table glass 21. The light irradiated from the light source 22 is reflected by the document and forms an image on the CCD sensor 24 via an optical system member 23 such as a lens. By scanning in the direction of the arrow, such an optical system unit converts the document into an electrical signal data series for each line. The image signal obtained by the CCD sensor 24 is sent to the main body 3 of the image forming apparatus, and image processing is performed by the control unit 30 according to each image forming unit described later. Also, the control unit 30 receives an external input from an external host device such as a print server as an image signal.

[0052] The main body 3 of the image forming apparatus includes a plurality of image forming units Pa, Pb, Pc, and Pd. In each image forming unit, image formation is performed based on the above-described image signal. That is, the image signal is converted into a laser beam PWM (pulse width modulation control) by the control unit 30. In FIG. 1, 31 is a polygon scanner as an exposure device, and scans a laser beam according to the image signal. Then, the laser beam is irradiated onto the photosensitive drums 200a to 200d as the image carriers of the respective image forming units Pa to Pd. Note that Pa is a yellow (Y) image forming unit, Pb is a magenta (M) image forming unit, Pc is a cyan (C) image forming unit, and Pd is a black (Bk) image forming unit, which form images of the corresponding colors respectively. Since the image forming units Pa to Pd are substantially the same, the details of the Y image forming unit Pa will be described below, and the description of the other image forming units will be omitted. In the Y image forming unit Pa, 200a is a photosensitive drum, and as described below, a toner image is formed on the surface based on the image signal.

[0053] 201a is a primary charger that charges the surface of the photosensitive drum 200a to a predetermined potential to prepare for electrostatic latent image formation. An electrostatic latent image is formed on the surface of the photosensitive drum 200a charged to a predetermined potential by a laser beam from the polygon scanner 31. 202a is a developing unit that develops the electrostatic latent image on the photosensitive drum 200a to form a toner image. 203a is a transfer roller that discharges from the back of the intermediate transfer belt 204 and applies a primary transfer bias of the opposite polarity to the toner, and transfers the toner image on the photosensitive drum 200a onto the intermediate transfer belt 204. After the transfer, the surface of the photosensitive drum 200a is cleaned by the cleaner 207a.

[0054] Also, the toner image on the intermediate transfer belt 204 is conveyed to the next image forming unit, and in the order of Y, M, C, Bk, toner images of each color formed in each image forming unit are sequentially transferred, and a four-color image is formed on its surface. The toner image that has passed through the Bk image forming unit is secondarily transferred to the recording material P by applying a secondary transfer electric field of the opposite polarity to the toner image on the intermediate transfer belt 204 in the secondary transfer unit composed of the secondary transfer roller pair 205 and 206. The recording material fed from the paper feed cassette 8 or 9 waits at the registration unit 208, and then the timing is controlled to align the position of the toner image on the intermediate transfer belt with the recording material, and the recording material is conveyed from the registration unit. Thereafter, the toner image on the recording material is fixed to the recording material by the fixing device 300 as an image heating device. After passing through the fixing device, it is discharged outside the machine. In the case of a duplex job, when the transfer and fixing of the toner on the first side (the first side) of the image formation are completed, the recording material passes through the inversion unit provided inside the image forming apparatus after fixing, and the front and back of the recording material are inverted, and the transfer and fixing of the toner on the second side (the second side) of the image formation and the discharge outside the machine are performed, and it is stacked on the discharge tray 7.

Example

[0055] Hereinafter, the present disclosure will be specifically described using examples. Note that the sliding member and the fixing device according to the present disclosure are not limited to the configurations embodied in the following examples.

[0056] <Example A-1> (Preparation of the base material) A plate-shaped substrate made of stainless steel (SUS304) with a thickness of 1.3 mm, a width of 27.5 mm, and a length of 390 mm orthogonal to the width direction was prepared. Next, first convex portions were formed on one surface of the substrate by chemical etching. Each of the first convex portions had a frustum of a cone shape with a top surface diameter of 350 μm, a height of 250 μm, a bevel angle of 65°, and a bottom surface diameter of 584 μm. Also, 8,750 first convex portions were formed such that the center-to-center distance of the top surfaces in the X and Y directions of the substrate was 1.4 mm.

[0057] (Formation of Resin Layer) A dispersion of polyetheretherketone (PEEK) (trade name: VICOTE (registered trademark) F817, manufactured by Victrex) was prepared. Next, the substrate prepared above was fitted into a mandrel and rotated at 200 rpm, and the dispersion was applied using a spray gun (trade name: W-101, manufactured by Anest Iwata Corporation) to form a coating film of the dispersion. Next, the substrate with the coating film formed thereon was placed in a heating furnace and heated at a temperature of 120°C for 5 minutes to dry the coating film, and then heated at a temperature of 400°C for 15 minutes to bake the coating film so that the thickness became 5 μm. A first PEEK resin layer was formed.

[0058] On the first PEEK resin layer created above, a dispersion of polyetheretherketone (PEEK) (product name: VICOTE (registered trademark) F804, manufactured by Victrex) was applied using a spray gun (product name: W-101, manufactured by Anest Iwata Corporation) while rotating a substrate fitted with pins at 200 rpm to form a coating film of the above dispersion. Next, the substrate with the coating film formed thereon was placed in a heating furnace and heated at a temperature of 120°C for 5 minutes to dry the coating film, and then heated at a temperature of 400°C for 15 minutes to bake the coating film, thereby forming a second PEEK resin layer to a thickness of 30 μm. Thus, a resin layer containing PEEK was formed on the surface of the substrate on the side where the first convex portion of the substrate was formed. It was visually confirmed that a second convex portion corresponding to the first convex portion of the substrate was formed on the surface of the obtained resin layer on the side opposite to the side facing the substrate. The thickness of the resin layer covering the upper surface of the first convex portion was the same as the thickness of the resin layer covering the portion of the substrate without the first convex portion.

[0059] (Formation of recesses) Recesses were formed at the top of the second convex portion by the following method. A substrate coated with a resin layer so that the second convex portion was in contact was placed on a hot plate (600 mm in length × 600 mm in width × 60 mm in thickness) heated to a temperature of 200°C, and using a hot press machine (product name: 150-ton press machine, model: PEF-150, manufactured by Kansai Roll Co., Ltd.), the second convex portion was pressed against the hot plate so that a pressure of 4 MPa was applied, and this state was continued for 10 minutes. Then, the pressing state was released, and it was left standing in a normal temperature (25°C) environment. Thus, a recess was formed at the top of the second convex portion, and a sliding member according to Example 1 was obtained.

[0060] The obtained sliding member was subjected to the following evaluations.

[0061] <Evaluation 1> Contact area ratios A25 and A200, and evaluation of the recess at the top of the second convex portion As shown in Figure 9, a jig was prepared, including a square lower stage 901 with sides of 400 mm and a square upper stage 903 with sides of 500 mm. A square hole 903h with sides of 10 mm was provided in the center of the upper stage 903, and a transparent glass plate 902 was attached to the vertically lower surface of the upper stage to cover the hole. The glass plate was 20 mm on a side and 5 mm thick, made of BK7, and had optically polished surfaces on both sides, with a parallelism of less than 1 arc minute. The lower stage 901 could be raised and lowered in the direction of arrow 905 by an elevator (not shown). A load meter 904 was also installed on the jig to measure the pressure applied vertically from below to the upper stage 903.

[0062] In an environment at 25°C, the sliding member to be evaluated was placed on the lower stage 901 of the jig prepared above, with the side having the second convex portion facing vertically upward. The lower stage 901 was then raised vertically upward to press the surface of the sliding member with the second convex portion against the glass plate. When the pressure gauge reading reached 0.4 MPa, the raising of the lower stage 901 was stopped. The glass plate 902 was then observed at a magnification of 200x using a digital microscope 907 (product name: DIGITAL MICROSCOPE VHX-500, manufactured by Keyence Corporation) from the side opposite the side in contact with the sliding member, and images were obtained. The obtained images were then used in image analysis software (product name: "ImageProPlus," manufactured by Media Cybernetics) to obtain binarized images that allowed for differentiation of contact and non-contact areas between the glass plate and the sliding member. The Otsu method described in Non-Patent Document 1 was used for the binarization process. From this binarized image, it was determined whether or not there was a recess at the top of the second convex portion and an edge surrounding the recess. Furthermore, from the above judgment, it was found that the depression at the top of the second protrusion and all of the contact portions where the edge surrounding the depression exist are not formed by the second protrusion coming into contact with the glass plate. The area x1 of the edge surrounding the recess and the area y1 of the recess surrounded by the edge and not in contact with the glass plate were calculated. Here, the area y1 is the projection of the recess surrounded by the edge onto the glass plate. It is the area. Then, based on the following calculation formula (1), the contact area ratio (%) per one contact part between the second convex part and the glass plate was obtained, and their average value was calculated. Calculation formula (1) [x1 / (x1 + y1)]×100

[0063] The observation with the above digital microscope, the acquisition, determination of the binary image, the contact area ratio, and the calculation of their average values were performed at a total of three locations: the central part in the width direction orthogonal to the longitudinal direction of the sliding member, and positions 90 mm from the central part toward both ends in the longitudinal direction. The average value of the average values of the contact area ratios at these three locations was defined as the contact area ratio A25 of the sliding member to be evaluated.

[0064] Except that the measurement environmental temperature was set to 200°C, in the same manner as the calculation method of the above A25, the contact area ratio A200 was calculated according to the following calculation formula (2). Calculation formula (2) [x2 / (x2 + y2)]×100 In calculation formula (2), when a glass plate is pressed against the surface having the second convex part of the fixing sliding member at a pressure of 0.4 MPa at a temperature of 200°C, and the edge surrounding the concave part comes into contact with the glass plate, x2 represents the area of the edge in contact with the glass plate at a temperature of 200°C, and y2 represents the projected area of the concave part surrounded by the edge on the glass plate at a temperature of 200°C.

[0065] <Evaluation 2> Measurement of the storage elastic modulus (E´25, E´200) of the resin layer The storage elastic moduli E´25 and E´200 of the resin layer of the sliding member to be evaluated were measured using a "dynamic viscoelasticity measuring device (trade name: Rheogel E4000, manufactured by UBM Co., Ltd.)". It was determined. Specifically, test pieces (thickness: 20 to 40 μm, width: 5 mm, length: 20 mm) having the same composition as the resin layer were prepared. The test pieces were attached to the tensile jig of the above dynamic viscoelasticity measuring device, and a sine wave with a chuck distance of 10 mm, a frequency of 10 Hz, and an amplitude of 0.03 mm was used, and the measurement temperature was raised from 20 °C to 250 °C at a heating rate of 5.0 °C / min. Values E25 and E250 at temperatures of 25 °C and 250 °C were calculated respectively.

[0066] <Evaluation 3> <Measurement of Torque> For this evaluation, a full-color electrophotographic image forming apparatus (product name: image PRESS V1000; manufactured by Canon Inc.) was prepared. First, 50 ml of a lubricant was applied to the surface of the evaluation target sliding member on the side where the second convex portion was formed. The lubricant contained perfluoropolyether (product name: Demnum S-200; manufactured by Daikin Industries, Ltd.) as a base oil, and as a thickener, it contained 30% by mass of fluororesin particles (product name: Rubron L-5F; manufactured by Daikin Industries, Ltd.) with respect to the lubricant. The above base oil had a kinematic viscosity at a temperature of 40 °C of 200 mm 2 / s. Next, the sliding member fixed to the outer surface of the pad of the fixing device of the above full-color electrophotographic image forming apparatus was removed, and the evaluation target sliding member prepared above and having the lubricant applied to its surface was attached. Next, the above full-color electrophotographic image forming apparatus was set with the heater set temperature at 200 °C, and the fixing rotating body was driven to rotate by rotating the pressure roller for 1 minute. Then, the power of the full-color electrophotographic image forming apparatus was turned off and left in an environment at a temperature of 25 °C for 24 hours. Subsequently, the power of the above full-color electrophotographic image forming apparatus was turned on, and the maximum value (starting torque) of the axial torque of the pressure roller when the pressure roller started to rotate was measured.

[0067] <Example A-2> ​A sliding member was produced in the same manner as in Example A-1, except that the resin layer was formed such that the thickness of the resin layer in the second convex portion and the thickness of the resin layer other than the second convex portion were both 20 μm. The obtained sliding member was subjected to Evaluations 1 to 3 described in Example A-1.

[0068] <Example A-3> A sliding member was produced in the same manner as in Example A-2, except that the constituent material of the resin layer was changed to a resin liquid (trade name: VICOTE F810, manufactured by Victrex) in which polytetrafluoroethylene was dispersed in a dispersion of polyetheretherketone (PEEK). The obtained sliding member was subjected to Evaluations 1 to 3 described in Example A-1.

[0069] <Example A-4> A sliding member was produced in the same manner as in Example A-3, except that the resin layer was formed such that the thickness of the resin layer in the second convex portion and the thickness of the resin layer other than the second convex portion were both 30 μm. The obtained sliding member was subjected to Evaluations 1 to 3 described in Example A-1.

[0070] <Example A-5> In the step of forming the concave portion at the top of the second convex portion in Example A-4, the pressure applied to the second convex portion was set to 3 MPa. Otherwise, a sliding member was produced in the same manner as in Example A-3. The obtained sliding member was subjected to Evaluations 1 to 3 described in Example A-1.

[0071] <Example A-6> In the formation of the resin layer in Example 5, a sliding member 304 of Example 6 was produced in the same manner as in Example 5, except that the ratio of the number of the second convex portions having concave portions at the top (hereinafter also referred to as "formation ratio of concave portions") to the total number of the second convex portions was changed to 80% by number.

[0072] <Example A-7> In the formation of the resin layer in Example 5, a sliding member 304 of Example 7 was produced in the same manner as in Example 5, except that the formation ratio of concave portions was changed to 50% by number.

[0073] <Comparative Example A-1> In Comparative Example A-1, a sliding member was produced in the same manner as in Example 1, except that the step of forming a concave portion at the top of the second convex portion was not performed. The obtained sliding member was subjected to Evaluations 1 to 3 described in Example A-1.

[0074] Table 1 shows the evaluation results of the sliding members according to Examples A-1 to A-7 and Comparative Example A-1.

[0075]

Table 1

[0076] As is clear from the results in Table 1, the starting torque of the fixing device could be significantly reduced by providing a concave portion at the top of the second convex portion.

[0077] <Example B-1> Using each of the sliding members according to Example A-1, a fixing test of an unfixed toner image formed on an OHT film was carried out. In the same manner as in Evaluation 3 of Example A-1, the sliding member according to Example A-1 was attached to the pad. A full-color electrophotographic image forming apparatus was prepared. Using this full-color electrophotographic image forming apparatus, 10 consecutive melting unevenness evaluation images in which cyan toner and magenta toner were formed over the entire area of an A4-size OHT film (product name: VF-1420N, manufactured by Kokuyo Co., Ltd.) at 100% density were fixed. Here, in the nip portion N, if unevenness in nip pressure occurs without the pressure (nip pressure) applied from the fixing rotating body to the unfixed toner image being applied to the concave portion formed at the top of the second convex portion of the sliding member, it may appear as fixing unevenness in the image. Specifically, for example, the melting of cyan toner and magenta toner may be insufficient, and these toners may not be sufficiently mixed, resulting in color unevenness. Therefore, the tenth image was visually observed and evaluated according to the following criteria.

[0078] Evaluation Criteria Rank A: No color unevenness due to uneven nip pressure was observed in the image. Rank B: Color unevenness due to uneven nip pressure was observed in a small part of the image. Rank C: Significant color unevenness was observed due to uneven nip pressure caused by contact of the edges surrounding the recesses.

[0079] <Examples B-2 to B-7> Each of the sliding members according to Examples A-2 to A-7 was subjected to the evaluation described in Example B-1 above. The results of Examples B-1 to B-7 are shown in Table 2.

[0080] [Table 2] As shown in Table 2, the evaluation rank of Example B-3 using the sliding member of Example A-3 was Rank B. The reason for this is that the A200 value of the sliding member of Example A-3 was 31%, which was smaller than the A200 values of the sliding members of Examples A-1 to A-2 and A-4 to A-7. This is thought to be because the nip pressure was small at the center of the recess of the second convex portion, resulting in a slight non-uniformity of the nip pressure.

[0081] The present disclosure relates to the following configurations. (Configuration 1) A fixing sliding member, a metal substrate having a plurality of first protrusions on at least one surface; a resin layer that covers the surface of the first convex portion of the metal base, On the surface of the resin layer opposite to the surface facing the metal substrate, a plurality of second protrusions corresponding to the plurality of first protrusions; At least one of the plurality of second protrusions has at least one recess at its top, A fixing sliding member in which, when a glass plate is pressed against the surface of the fixing sliding member having the plurality of second convex portions at a pressure of 0.4 MPa at a temperature of 25°C, the edge surrounding the concave portion comes into contact with the glass plate. (Configuration 2) The fixing sliding member of Configuration 1, wherein the depth of the concave portion surrounded by the edge portion is 1.0 μm or more. (Configuration 3) The fixing sliding member of Configuration 1 or 2, wherein the equivalent diameter of the area of the concave portion surrounded by the edge portion is 20 to 600 μm. (Configuration 4) The fixing sliding member of any one of Configurations 1 to 3, wherein when a glass plate is pressed against the surface having the second convex portion of the fixing sliding member at a temperature of 200° C. with a pressure of 0.4 MPa, the edge portion surrounding the concave portion contacts the glass plate. (Configuration 5) Regarding the average value of the contact area ratio represented by the following calculation formula (1) at a temperature of 25° C. as A25, The fixing sliding member of Configuration 4, wherein when the average value of the contact area ratio represented by the following calculation formula (2) at a temperature of 200° C. is A200, A25 < A200: [x1 / (x1 + y1)]×100 (1) (In the calculation formula (1), x1 represents the area of the edge portion in contact with the glass plate at a temperature of 25° C., y1 represents the projected area of the concave portion surrounded by the edge portion onto the glass plate at a temperature of 25° C.) [x2 / (x2 + y2)]×100 (2) (In the calculation formula (2), x2 represents the area of the edge portion in contact with the glass plate at a temperature of 200° C., y2 represents the projected area of the concave portion surrounded by the edge portion onto the glass plate at a temperature of 200° C.) (Configuration 6) The fixing sliding member of Configuration 5, wherein A200 is 2 times or more of A25. (Configuration 7) The fixing sliding member of Configuration 5 or 6, wherein A200 is 30% or more and 80% or less. (Configuration 8) The fixing sliding member of any one of Configurations 5 to 7, wherein A200 is 40% or more and 80% or less. (Configuration 9) The fixing sliding member of any one of Configurations 5 to 8, wherein A25 is 10% or more and 50% or less. (Configuration 10) For the resin layer When the storage elastic modulus at a temperature of 25°C is E´(25), and the storage elastic modulus at a temperature of 200°C is E´(200), E´(25) is 2.5 to 4.0 GPa, and E´(200) is 0.06 to 0.13 times that of E25, the fixing sliding member of any one of Configurations 1 to 9. (Configuration 11) The fixing sliding member of any one of Configurations 1 to 10, wherein the resin layer contains polyetheretherketone. (Configuration 12) A fixing device for fixing an unfixed toner image carried on a recording material to the recording material, a rotating member for fixing, a pressing rotating member disposed opposite to the rotating member for fixing and forming a nip portion together with the rotating member for fixing, a sliding member disposed inside the rotating member for fixing and having a sliding surface slidable with the inner peripheral surface of the rotating member for fixing via a lubricant, a backup member disposed inside the rotating member for fixing to sandwich the sliding member and the rotating member for fixing between the backup member and the pressing rotating member, and backing up the sliding member, a heater for heating the rotating member for fixing, wherein the sliding member is a fixing sliding member of any one of Configurations 1 to 11, and the surface of the fixing sliding member having the plurality of second convex portions faces the inner peripheral surface of the rotating member for fixing, a fixing device characterized by this.

Explanation of Reference Numerals

[0082] 300 Fixing device 301 Rotating member for fixing 303 Pad (backup member) 304 Sliding member 304a Base material 304b Resin layer 405 First convex portion 407 Second convex part 408 Concave part 413 Edge part

Claims

1. A fixing sliding member, comprising: a metal base material having a plurality of first convex portions on at least one surface; a resin layer covering the surface of the first convex portions of the metal base material; a plurality of second convex portions corresponding to the plurality of first convex portions on a side of a surface of the resin layer opposite to a side facing the metal base material; at least one of the plurality of second convex portions having at least one concave portion at its top; when a glass plate is pressed against a surface of the fixing sliding member having the plurality of second convex portions at a temperature of 25° C. with a pressure of 0.4 MPa, an edge surrounding the concave portion comes into contact with the glass plate, characterized in that the fixing sliding member is provided with the above features.

2. The fixing sliding member according to claim 1, wherein a depth of the concave portion surrounded by the edge is 1.0 μm or more.

3. The fixing sliding member according to claim 1, wherein an equivalent diameter of an area of the concave portion surrounded by the edge is 20 to 600 μm.

4. The fixing sliding member according to claim 1, wherein when a glass plate is pressed against a surface of the fixing sliding member having the second convex portions at a temperature of 200° C. with a pressure of 0.4 MPa, an edge surrounding the concave portion comes into contact with the glass plate.

5. When an average value of a contact area ratio represented by the following calculation formula (1) at a temperature of 25° C. is defined as A25, and an average value of a contact area ratio represented by the following calculation formula (2) at a temperature of 200° C. is defined as A200, A25 < A200, the fixing sliding member according to claim 4: [x1 / (x1 + y1)] × 100 (1) (In the calculation formula (1), x1 represents an area of the edge in contact with the glass plate at a temperature of at least 25° C., y1 represents a projected area of the concave portion surrounded by the edge onto the glass plate at a temperature of 25° C.). [x2 / (x2 + y2)] × 100 (2) In the calculation formula (2), x2 represents an area of the edge in contact with the glass plate at a temperature of 200° C., y2 represents a projected area of the concave portion surrounded by the edge onto the glass plate at a temperature of 200° C.).

6. The fixing sliding member according to claim 5, wherein A200 is at least twice A25.

7. The fixing sliding member according to claim 5, wherein A200 is 30% or more and 80% or less.

8. The fixing sliding member according to claim 6, wherein A200 is 40% or more and 80% or less.

9. The fixing sliding member according to claim 5, wherein A25 is 10% or more and 50% or less.

10. For the resin layer, when the storage elastic modulus at a temperature of 25°C is defined as E'(25), and the storage elastic modulus at a temperature of 200°C is defined as E'(200), E'(25) is 2.5 to 4.0 GPa, and E'(200) is 0.06 to 0.13 times that of E25. The fixing sliding member according to claim 1.

11. The fixing sliding member according to claim 1, wherein the resin layer contains polyether ether ketone.

12. A fixing device for fixing an unfixed toner image carried on a recording material to the recording material, comprising: a rotating member for fixing; a pressing rotating member disposed opposite to the rotating member for fixing and forming a nip portion together with the rotating member for fixing; a sliding member disposed inside the rotating member for fixing and having a sliding surface slidable with the inner peripheral surface of the rotating member for fixing via a lubricant; a backup member disposed inside the rotating member for fixing and sandwiching the sliding member and the rotating member for fixing between the backup member and the pressing rotating member to backup the sliding member; a heater for heating the rotating member for fixing, wherein the sliding member is the fixing sliding member according to any one of claims 1 to 11, and the surface of the fixing sliding member having the plurality of second convex portions is disposed to face the inner peripheral surface of the rotating member for fixing. The fixing device is characterized by this.

Images