Electrophotographic components, fixing devices and electrophotographic image forming equipment

Abstract

This invention relates to an electrophotographic component, a fixing device, and an electrophotographic image forming apparatus. An electrophotographic component includes a substrate and an elastic layer disposed on the outer periphery of the substrate, wherein the elastic layer comprises rubber and fillers dispersed in the rubber, the filler content in the elastic layer is 15 to 50% by volume, and the filler A content V in the elastic layer is... A The content of filler A in the elastic layer is 7% to 30% by volume, and the average aspect ratio of filler A is 3.0 to 40.0. B The average aspect ratio of packing B is 1.0 to 2.0, ranging from 7% to 30% by volume, and the average orientation angle θ of packings with a specific aspect ratio is also specified. Ave The range is from 0° to 45°.

Description

Technical Field

[0001] This disclosure relates to an electrophotographic component used in a fixing apparatus of an electrophotographic image forming device, and to a fixing apparatus and an electrophotographic image forming device including an electrophotographic component. Background Technology

[0002] For example, electrophotographic components used in the fixing devices of electrophotographic image forming equipment such as printers, copiers, and fax machines have a film shape or a roller shape. As fixing components, for example, it is known to form an elastic layer made of heat-resistant rubber on a film-shaped or roller-shaped substrate made of heat-resistant resin or metal, as needed. To make the elastic layer exhibit high thermal conductivity, it is preferable to use a material in which inorganic fillers with high thermal conductivity are added, such as fillers in rubbers like silicone rubber.

[0003] In recent years, there has been a demand for additional performance improvements in electrophotographic image forming equipment, such as even faster printing speeds, higher image quality, energy efficiency, and support for a wider range of media. In the fixing unit, there is a need to increase the surface pressure in the fixing roller gap to increase toner deformation and improve image quality. Furthermore, in the fixing component, there is a need to further improve the thermal conductivity in the thickness direction of the elastic layer.

[0004] However, when the amount of filler added to the elastic layer is increased to make the elastic layer exhibit higher thermal conductivity, the elastic layer may crack after long-term use, leading to durability issues. Therefore, a technique is needed to improve the thermal conductivity of the elastic layer without excessively increasing the filler content.

[0005] Japanese Patent Application Publication No. 2023-095891 discloses an electrophotographic component with an elastic layer comprising small-diameter fillers aligned in the thickness direction of the elastic layer and large-diameter fillers misaligned in the thickness direction of the elastic layer. This allows for improved thermal conductivity without increasing the amount of filler.

[0006] Furthermore, Japanese Patent Application Publication No. 2020-194156 discloses an electrophotographic component in which a binarized image of a cross-section of an elastic layer includes a first filler with a major axis / minor axis ratio less than 1.5 and a second filler with a major axis / minor axis ratio greater than 1.5, wherein the second filler is oriented in the thickness direction of the elastic layer. This allows for improved thermal conductivity without increasing the amount of filler. Summary of the Invention

[0007] In Japanese Patent Application Publication No. 2023-095891, it was found that when the filler is aligned in the thickness direction to form a heat conduction path, thermal conductivity can be improved compared to when the filler is not aligned in the thickness direction. However, to obtain even higher thermal conductivity, the filler content needs to be increased to a certain level, and achieving both thermal conductivity and durability is a challenge.

[0008] Therefore, compared with the use of fillers with low aspect ratios, when fillers with high aspect ratios are oriented in the thickness direction of the elastic layer to form a heat conduction path, such as the second filler in Japanese Patent Application Publication No. 2020-194156, high thermal conductivity can be obtained with a small filler content.

[0009] However, the inventors recognized that when an electrophotographic component is used as a fixing component under conditions where the maximum surface pressure of the fixing device in the fixing roller gap increases, there is a problem of achieving both thermal conductivity and durability, even if the filler with a high aspect ratio is oriented in the thickness direction of the elastic layer.

[0010] This disclosure provides an electrophotographic component with high thermal conductivity and high durability, wherein the elastic layer is unlikely to break even after long-term use under conditions where the maximum surface pressure in the fixing roller gap is higher than in the past. Furthermore, the present invention provides a fixing apparatus and an electrophotographic image forming device including this electrophotographic component.

[0011] This disclosure relates to an electrophotographic component, which is a rotating component comprising a substrate and an elastic layer disposed on the outer periphery of the substrate.

[0012] The elastic layer comprises rubber and fillers dispersed in the rubber.

[0013] The filler content in the elastic layer is 15% to 50% by volume.

[0014] In packing materials, packing material with a particle size greater than 3 μm and less than 10 μm is defined as packing material A, and...

[0015] When fillers with a particle size of 10 to 40 μm are defined as filler B,

[0016] The content of filler A in the elastic layer V A 7% to 30% by volume

[0017] The average aspect ratio of packing A is 3.0 to 40.0.

[0018] The content of filler B in the elastic layer V B 7% to 30% by volume

[0019] The average aspect ratio of packing B is 1.0 to 2.0.

[0020] When the plane of the elastic layer in the thickness-circumferential direction is defined as the first plane, and the planes rotated from the first plane in increments of 10° toward the plane of the elastic layer in the thickness-axial direction are defined as the second to tenth planes,

[0021] Cross-sectional images with dimensions corresponding to the full thickness of the elastic layer × 500 μm are acquired as first to tenth cross-sectional images, such that the images are parallel to the first to tenth planes, and their centers in the direction perpendicular to the thickness direction of the elastic layer are aligned with the center of the electron imaging component in the axial direction.

[0022] The images of the first to tenth cross sections are binarized to form the first to tenth binarized images, and

[0023] In the first through tenth binarized images, when the shape of the filler is approximately elliptical,

[0024] The filler is roughly elliptical and has a major axis length / minor axis length ratio of 2.0 or greater, with an average orientation angle θ of 0° to 45° relative to the thickness direction of the elastic layer. Ave .

[0025] This disclosure relates to a fixing device, which includes:

[0026] Fixing components; and

[0027] A pressure member faces the fixing member and forms a fixing roller gap between the pressure member and the fixing member. The fixing roller gap holds and transports recording material carrying toner images.

[0028] At least one of the fixing component and the pressurizing component is the aforementioned electrophotographic component.

[0029] This disclosure relates to an electrophotographic image forming apparatus including a fixing device.

[0030] The fixing device is the aforementioned fixing device.

[0031] The features of this disclosure will become apparent from the following description of the embodiments with reference to the accompanying drawings. The following description of the embodiments is illustrated by way of example. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of an electrophotographic image forming device.

[0033] Figure 2 This is a schematic diagram of a thermal fixing device.

[0034] Figure 3 This is a schematic diagram of the fixing film.

[0035] Figure 4A and Figure 4B These are bird's-eye view and cross-sectional view of the corona charging equipment.

[0036] Figure 5 This is a schematic diagram of the first to tenth planes.

[0037] Figure 6 This is a schematic diagram of the first to tenth sections. Detailed Implementation Plan

[0038] In this disclosure, unless otherwise stated, the description of a numerical range, "from XX to YY" or "XX to YY," refers to a numerical range that includes a lower limit and an upper limit as endpoints. Furthermore, when a numerical range is described stepwise, the upper and lower limits of each numerical range can be arbitrarily combined. Additionally, in this disclosure, a description such as "selected from at least one of the groups 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. When XX represents a group, multiple members can be selected from XX, and the same applies to YY and ZZ.

[0039] The embodiments of this disclosure will be described in detail below. However, the technical scope of this disclosure is not limited to the following description.

[0040] As described above, when the maximum surface pressure in the fixing roller gap of the fixing device increases, even if the filler with a high aspect ratio is oriented in the thickness direction of the elastic layer in the electrophotographic component, there is a problem in achieving both thermal conductivity and durability. The inventors speculate the reason is as follows.

[0041] When stress is applied to the elastic layer, stress concentration may occur near the filler due to its restriction on rubber deformation, potentially leading to microcracks. Since severe stress concentration also occurs near microcracks, if numerous microcracks develop in the elastic layer, they can influence each other and grow into larger cracks. Because shear stress is applied to the elastic layer in the fixing roller gap, it is believed that this phenomenon occurs when the elastic layer fractures after prolonged use of the fixing component.

[0042] In this situation, the higher the aspect ratio and the larger the particle size of the packing material, the more severe the stress concentration becomes near the top of the packing material. Furthermore, the stress concentration becomes more severe as the distance between adjacent packing materials becomes shorter. Therefore, it is speculated that when packing materials with high aspect ratios are oriented in the thickness direction of the elastic layer, the stress distribution in the elastic layer may become uneven.

[0043] Under conditions of high maximum surface pressure in the fixing roller gap, if the stress distribution in the elastic layer is uneven, the local stress value becomes too high, leading to numerous microcracks in the elastic layer. Therefore, it is believed that the elastic layer will crack after long-term use, resulting in durability issues.

[0044] The inventors have conducted extensive research and discovered that the following configuration can achieve both thermal conductivity and durability.

[0045] This disclosure relates to an electrophotographic component, which is a rotating component comprising a substrate and an elastic layer disposed on the outer periphery of the substrate.

[0046] The elastic layer comprises rubber and fillers dispersed in the rubber.

[0047] The filler content in the elastic layer is 15% to 50% by volume.

[0048] In packing materials, packing material with a particle size greater than 3 μm and less than 10 μm is defined as packing material A, and...

[0049] When fillers with a particle size of 10 to 40 μm are defined as filler B,

[0050] The content of filler A in the elastic layer V A 7 to 30% by volume

[0051] The average aspect ratio of packing A is 3.0 to 40.0.

[0052] The content of filler B in the elastic layer V B 7 to 30% by volume

[0053] The average aspect ratio of packing B is 1.0 to 2.0.

[0054] When the plane of the elastic layer in the thickness-circumferential direction is defined as the first plane, and the planes rotated from the first plane in increments of 10° toward the plane of the elastic layer in the thickness-axial direction are defined as the second to tenth planes,

[0055] Cross-sectional images with dimensions corresponding to the full thickness of the elastic layer × 500 μm are acquired as first to tenth cross-sectional images, such that the images are parallel to the first to tenth planes, and their centers in the direction perpendicular to the thickness direction of the elastic layer are aligned with the center of the electron imaging component in the axial direction.

[0056] The first to tenth cross-sectional images are binarized to form the first to tenth binarized images, and

[0057] In the first through tenth binarized images, when the shape of the filler is approximately elliptical,

[0058] The filler is roughly elliptical and has a major axis length / minor axis length ratio of 2.0 or greater, with an average orientation angle θ of 0° to 45° relative to the thickness direction of the elastic layer. Ave .

[0059] The electrophotographic component disclosed herein includes filler A and filler B. The mechanism by which the thermal conductivity and durability of the elastic layer are improved through a combination of filler A having a small particle size and a large aspect ratio, filler B having a large particle size and a small aspect ratio, and fillers present within the elastic layer.

[0060] First, considering thermal conductivity, it is essential to incorporate fillers with a high aspect ratio and a distribution of both large and small filler particle sizes. When using fillers with a high aspect ratio, heat is efficiently transferred along the orientation direction of the filler, and thermal conductivity in the thickness direction can be increased without excessively increasing the total filler volume. Furthermore, when the filler particle size distribution spans both large and small diameters, the gaps between the large-diameter fillers are filled with small-diameter fillers to form heat conduction paths, and the elastic layer exhibits excellent thermal conductivity in the thickness direction.

[0061] Therefore, when the filler content V A and V B The aspect ratio of filler A is set to be equal to or greater than the lower limit, and the average value of the orientation angle θ is set to be greater than or equal to the lower limit. Ave When set within the above range, thermal conductivity becomes advantageous.

[0062] Next, considering durability, when large stress is applied to the elastic layer, in order to prevent the rubber from breaking due to the large stress applied to the rubber matrix, a distribution of large and small filler particle sizes is required, and the combination of adjacent fillers at the stress concentration points should be reduced.

[0063] When the filler particle size distribution spans both large and small diameters, it is easy to form a uniform dispersion state in which small diameter particles enter the gaps between large diameter particles. Even when a large strain is applied to the elastic layer, the stress is dispersed throughout the matrix, which can minimize the occurrence of cracks and thus achieve excellent durability.

[0064] Furthermore, microcracks occur when large stresses are applied to areas where the fillers are close to each other. Once a microcrack occurs, the stress concentrates at the cracked portion, and the crack propagates as it connects with other adjacent microcracks, eventually causing the elastic layer to fracture. Therefore, since the presence of numerous microcracks within the elastic layer reduces durability, it is necessary to select a filler combination that can reduce the frequency of microcrack occurrence to improve durability.

[0065] Regarding stress concentration that causes microcracks, as the particle size of the packing increases, the deformation of the matrix becomes more restricted, leading to greater stress concentration. This stress concentration is even greater when the packing has small curvature at its tips that are close to each other. Therefore, the combination of adjacent packings that causes the maximum stress concentration is the combination of large-diameter and high-aspect-ratio packings, and the next maximum stress concentration occurs in combinations of both large-diameter and high-aspect-ratio packings and small-diameter and high-aspect-ratio packings.

[0066] Therefore, it is believed that by controlling the amount of filler to prevent overfilling, using low aspect ratio fillers for large-diameter fillers, and controlling the aspect ratio of small-diameter fillers to prevent excessive amounts, the frequency of microcrack occurrence can be significantly reduced. Therefore, considering durability, it is important to control the filler content V... A and V B Set to be equal to or lower than the upper limit, and control the aspect ratio of packing A and packing B.

[0067] As described above, by combining large-diameter and low-aspect-ratio fillers with small-diameter and high-aspect-ratio fillers, controlling the content of these fillers, and further controlling the orientation of the high-aspect-ratio fillers, it is possible to obtain electrophotographic components with thermal conductivity and durability.

[0068] These requirements will be described below.

[0069] The elastic layer contains filler. Filler can be added to control properties such as thermal conductivity, heat resistance, and elastic modulus. The filler content in the elastic layer ranges from 15% to 50% by volume. When the filler content is above 15% by volume, the elastic layer can exhibit high thermal conductivity and favorable fixing properties. When the filler content is below 50% by volume, sufficient spacing can be maintained between the fillers. Therefore, when large stresses are applied to the elastic layer, the formation of microcracks in the elastic layer due to stress concentration between adjacent fillers can be minimized, resulting in excellent durability.

[0070] The filler content in the elastic layer is preferably 25% to 45% by volume, more preferably 27% to 40% by volume, and even more preferably 28% to 35% by volume.

[0071] In packing materials, packing materials with a particle size of 3 μm or more but less than 10 μm are defined as packing material A, and packing materials with a particle size of 10 μm to 40 μm are defined as packing material B.

[0072] In this case, the content V of filler A in the elastic layer A The content of filler A is 7% to 30% by volume, and the average aspect ratio of filler A is 3.0 to 40.0. Additionally, the content of filler B in the elastic layer is V... B The aspect ratio of filler B is 7% to 30% by volume, and the average aspect ratio of filler B is 1.0 to 2.0.

[0073] When VA Excellent thermal conductivity is achieved when V is above 7% by volume, and when V A Excellent durability is achieved when the filler content is 30% or less by volume. Furthermore, when the average aspect ratio of filler A is 3.0 or higher, thermal conductivity in the thickness direction can be increased without excessively increasing the total filler volume. Excellent durability is achieved when the average aspect ratio of filler A is 40.0 or less.

[0074] When V B Excellent thermal conductivity is achieved when V is above 7% by volume, and when V B Excellent durability is achieved when the content is below 30% by volume. Furthermore, excellent durability is achieved when the average aspect ratio of filler B is below 2.0.

[0075] To further improve thermal conductivity and durability, V A Preferably, it is 12% to 25% by volume, more preferably 13% to 20% by volume. The average aspect ratio of filler A is preferably 5.0 to 40.0, more preferably 7.0 to 12.0, and even more preferably 8.0 to 10.0. B Preferably, it is 12% to 25% by volume, more preferably 13% to 20% by volume. The average aspect ratio of filler B is preferably 1.0 to 1.7, more preferably 1.2 to 1.6.

[0076] To further improve thermal conductivity and durability, packing A preferably comprises a flat-shaped packing, more preferably a flat-shaped packing. Packing B preferably comprises a spherical or substantially spherical packing with an aspect ratio of 1.0 to 2.0.

[0077] One hundred fillers were observed using field emission scanning electron microscopy (FE-SEM), and V A+B It is achieved by increasing the volume V of packing A f and the volume V of packing B f The sum divided by the total volume V of all packing materials f The value obtained by summing V. A+B It is the total proportion of filler A and filler B in the filler contained in the elastic layer.

[0078] V A+B For example, 0.80 or higher, preferably 0.90 or higher, more preferably 0.95 or higher, and even more preferably 0.97 or higher. A+B There is no specific upper limit for V. A+B For example, 0.80 to 1.00, preferably 0.90 to 1.00, more preferably 0.95 to 1.00, and even more preferably 0.97 to 0.99.

[0079] V A / V BThe value is, for example, 0.4 to 3.0, preferably 0.5 to 2.0, more preferably 0.6 to 1.5, and even more preferably 0.8 to 1.3. Within the above range, thermal conductivity and durability are more easily achieved.

[0080] Furthermore, the plane of the elastic layer in the thickness-circumferential direction is defined as the first plane, and the planes that rotate from the first plane toward the plane of the elastic layer in the thickness-axial direction in increments of 10° are defined as the second to tenth planes. Here, the circumferential direction is the circumferential direction of the rotating member, and the axial direction is the rotation axis direction of the rotating member.

[0081] Cross-sectional images with dimensions corresponding to the full thickness of the elastic layer × 500 μm are obtained as first to tenth cross-sectional images, such that each image is parallel to the first to tenth planes, and the center of the image in the direction perpendicular to the thickness direction of the elastic layer matches the center of the electrophotographic component in the axial direction.

[0082] The acquired first to tenth cross-sectional images are binarized to form first to tenth binarized images, and in the first to tenth binarized images, the shape of the filler is approximately elliptical.

[0083] As a roughly elliptical filler with a major axis length / minor axis length value of 2.0 or greater, the filler must have an average orientation angle θ of 0° to 45° relative to the thickness direction of the elastic layer. Ave When θ Ave Within the aforementioned range, thermal conductivity in the thickness direction can be increased without excessively increasing the total amount of filler in the elastic layer. Therefore, an electrophotographic component with improved thermal conductivity in the thickness direction can be obtained without reducing the durability of the elastic layer.

[0084] θ Ave Preferably, the angle is 0° to 40°, more preferably 0° to 30°, and even more preferably 0° to 25°. A smaller lower limit is preferred, and although there are no particular limitations, θ Ave The angle is preferably 10° to 40°, and can be 12° to 30° or 15° to 25°.

[0085] Average orientation angle θ of the filler Ave Preferably, this is controlled, for example, by applying an electric field to the elastic layer, as will be described below.

[0086] Electrophotographic components

[0087] The electrophotographic component according to at least one aspect of this disclosure is, for example, a fixing component. Furthermore, the electrophotographic component is a rotating component. The electrophotographic component may have a roller shape or a belt shape. For example, the electrophotographic component is a fixing belt. Additionally, the electrophotographic component may be an electrophotographic belt with an annular shape. The electrophotographic component includes a substrate and an elastic layer disposed on the outer periphery of the substrate. The electrophotographic component may have a surface layer on the outer peripheral surface of the elastic layer. The substrate may be, for example, a base layer. Depending on the needs, other layers may be disposed between the layers in the substrate, elastic layer, and surface layer, as well as on the inner peripheral surface side of the substrate and the outer peripheral surface side of the surface layer.

[0088] like Figure 2 and Figure 3 As shown, the fixing member 41 is, for example, a fixing film 41. The fixing member 41 includes a substrate 41b and an elastic layer 41c. The fixing member 41 may have a surface layer 41a on the outer peripheral surface of the elastic layer 41c. The surface layer 41a can serve as a release layer that is peelable relative to, for example, a toner. The surface layer 41a can form the outer surface of the electrophotographic member. Here, the surface layer 41a can be bonded to the surface of the elastic layer 41c via an adhesive layer (not shown). In addition, the substrate 41b may have an inner sliding layer (not shown) on its inner peripheral surface side.

[0089] These layers will be described in detail below.

[0090] Substrate

[0091] The material of the substrate 41b is not particularly limited, and any known electrophotographic component can be used. For example, metals such as aluminum, iron, stainless steel (SUS), and nickel and its alloys can be used, as well as heat-resistant resins such as polyimide. Stainless steel is preferred. The thickness of the substrate 41b is not particularly limited, but taking into account factors such as strength, flexibility, and heat capacity, the thickness is preferably 20 μm to 100 μm, more preferably 20 μm to 50 μm.

[0092] The outer surface of the substrate 41b may be surface treated to impart adhesion to the elastic layer 41c. For the surface treatment, one or a combination of two or more types of physical treatments such as sandblasting, grinding and polishing, and chemical treatments such as oxidation, coupling agent treatment and primer treatment may be used.

[0093] When an elastic layer 41c containing silicone rubber is formed on the surface of a substrate 41b, it is preferable to apply a primer to the surface of the substrate 41b to improve the adhesion between the substrate 41b and the elastic layer 41c. The primer used in the primer treatment can be, for example, a coating in which a silane coupling agent, a siloxane polymer, a hydrogenated methylsiloxane, an alkoxysilane, a reaction accelerating catalyst, and a colorant such as iron oxide red are appropriately added and dispersed in an organic solvent.

[0094] The primer can be appropriately selected based on the material of the substrate 41b, the type of the elastic layer 41c, or the form of the crosslinking reaction. Specifically, when the elastic layer 41c contains a large number of unsaturated aliphatic groups, a primer containing hydrosilyl groups is preferred to impart adhesion by reacting with the unsaturated aliphatic groups.

[0095] Other examples of primers include those containing alkoxy groups. Commercially available primers can be used. Furthermore, primer treatment includes the steps of applying the primer to the outer surface of the substrate 41b (the surface to which the elastic layer 41c will adhere) and then drying or firing it.

[0096] Inner sliding layer

[0097] An inner sliding layer can be provided on the inner circumferential surface of the substrate 41b. For the inner sliding layer, a resin with high durability and high heat resistance, such as polyimide resin, is suitable. Since the inner sliding layer gradually wears down through friction, it is preferable that this layer has a thickness that allows it to function adequately as a sliding layer during use. On the other hand, a thickness that does not interfere with the heat supply from the heater is preferred. Therefore, the thickness is preferably 5 to 20 μm, more preferably 10 to 15 μm. The inner sliding layer can be formed using known coating methods.

[0098] elastic layer

[0099] The elastic layer 41c is used to impart flexibility to the electrophotographic component to fix the fixing roller gap in the fixing device. Here, when the electrophotographic component is used as a heating component that comes into contact with the toner on the paper, the elastic layer 41c also serves as a layer to impart flexibility so that the surface of the heating component can conform to the non-uniformity of the paper.

[0100] The elastic layer 41c comprises rubber and fillers dispersed in the rubber. In the elastic layer, the rubber is, for example, a matrix. More specifically, the elastic layer 41c comprises rubber and fillers dispersed in the rubber, and is formed by curing a cured product obtained by curing a mixture comprising at least a rubber raw material (base polymer, crosslinking agent, etc.) and fillers.

[0101] The elastic modulus of the elastic layer 41c is preferably from 0.60 MPa to 2.00 MPa, more preferably from 0.65 MPa to 1.20 MPa, and even more preferably from 0.70 MPa to 0.90 MPa. When the elastic modulus is 0.60 MPa or higher, better durability is achieved, and when the elastic modulus is 2.00 MPa or lower, softness can be imparted.

[0102] The elastic modulus of elastic layer 41c can be controlled by the volume fraction of filler in the elastic layer. Furthermore, the elastic modulus of elastic layer 41c can also be changed by the amount of crosslinking agent contained in the rubber raw material.

[0103] Furthermore, considering the surface hardness of the electrophotographic component and the width of the roll gap to be formed, the thickness of the elastic layer can be appropriately designed. The thickness of the elastic layer 41c is preferably 150 to 500 μm, more preferably 200 to 400 μm, and even more preferably 200 to 300 μm.

[0104] Considering the advantageous fixing properties, the thermal conductivity of the elastic layer in the thickness direction is preferably 1.25 W / (m·K) or higher. More preferably, it is 1.40 W / (m·K) or higher. A higher thermal conductivity of the elastic layer in the thickness direction is preferred, and there is no particular upper limit, but for example, it is 1.25 to 2.50 W / (m·K) or 1.40 to 2.00 W / (m·K).

[0105] The elastic layer 41c preferably comprises silicone rubber with excellent heat resistance. That is, the rubber in the elastic layer is preferably silicone rubber. Furthermore, addition-curing liquid silicone rubber is preferably used as the raw material for the silicone rubber. The elastic layer 41c can be formed, for example, by applying an addition-curing liquid silicone rubber mixture to the outer surface of the substrate 41b and then heating and curing it. There are no particular limitations on the coating method, and known methods can be used.

[0106] Since silicone rubber blends are typically liquids, fillers are easily dispersed, and the elasticity of the resulting elastic layer can be easily adjusted by regulating the degree of crosslinking according to the type and amount of filler added. Therefore, silicone rubber blends are preferred.

[0107] The matrix functions as an elastic layer. The matrix preferably contains silicone rubber to provide this elastic layer function. Silicone rubber is preferred because it has high heat resistance, allowing it to remain flexible even in environments where temperatures reach approximately 240°C in areas where the sheet does not pass through. For example, a cured product of an addition-curing liquid silicone rubber can be used as the silicone rubber.

[0108] Liquid silicone rubber blends typically contain the following components (a) to (d).

[0109] Component (a): Organopolysiloxane having unsaturated aliphatic groups;

[0110] Component (b): Organopolysiloxane containing silicon-bonded active hydrogen;

[0111] Component (c): Catalyst;

[0112] Component (d): Filler

[0113] The components will be described below.

[0114] Component (a): Organopolysiloxane with unsaturated aliphatic groups

[0115] The organopolysiloxane having unsaturated aliphatic groups is an organopolysiloxane having unsaturated aliphatic groups such as vinyl groups, and at least one selected from the group consisting of compounds represented by formula (1) and compounds represented by formula (2). The organopolysiloxane having unsaturated aliphatic groups is preferably linear.

[0116]

[0117] In equation (1), m 1 It is an integer greater than or equal to 0 (preferably 500 to 1,100), n 1 It is an integer greater than or equal to 3 (preferably 10 to 40). Furthermore, in structure (1), R... 1 Each is independently a monovalent unsubstituted or substituted hydrocarbon group without an unsaturated aliphatic group, provided that at least one R 1 It is methyl, and R 2 Each is an independent unsaturated aliphatic group.

[0118]

[0119] In equation (2), n 2 R is a positive integer (preferably 500 to 1,100). 3 Each is independently a monovalent unsubstituted or substituted hydrocarbon group without an unsaturated aliphatic group, provided that at least one R 3 It is methyl, and R 4 Each is an independent unsaturated aliphatic group.

[0120] In equations (1) and (2), R can be obtained. 1 and R 3 Examples of monovalent unsubstituted or substituted hydrocarbon groups that do not have unsaturated aliphatic groups include the following groups.

[0121] Unsubstituted hydrocarbon groups

[0122] Alkyl groups (e.g., methyl, ethyl, propyl, butyl, pentyl, hexyl).

[0123] Aryl (e.g., phenyl).

[0124] • Substituted hydrocarbon group

[0125] Substituted alkyl groups (e.g., chloromethyl, 3-chloropropyl, 3,3,3-trifluoropropyl, 3-cyanopropyl, 3-methoxypropyl).

[0126] The organopolysiloxanes represented by formulas (1) and (2) have at least one methyl group directly bonded to a silicon atom to form a chain structure. However, for ease of synthesis and processing, R is preferred. 1 and R 3 Each of them is more than 50% methyl, preferably R 1 and R 3 All are methyl groups.

[0127] Additionally, R in equations (1) and (2) can be used to... 2 and R 4 Examples of unsaturated aliphatic groups include the following groups. Specifically, examples of unsaturated aliphatic groups include vinyl, allyl, 3-butenyl, 4-pentenyl, and 5-hexenyl. Among these groups, R is preferred. 2 and R 4 They are all vinyl because they are easy to synthesize and process and are inexpensive, and they are also easy to crosslink.

[0128] Considering moldability, the viscosity of component (a) is preferably 1,000 mm. 2 / s to 50,000mm 2 / s, more preferably 1,000mm 2 / s to 20,000mm 2 / s, and even better 3,000mm 2 / s to 8,000mm 2 / s. When the viscosity is 1,000 mm 2 At speeds above 50,000 mS, the required hardness of the elastic layer can be easily adjusted, and when the viscosity is 50,000 mS... 2 Applications become easier when the viscosity is below a certain value ( / s). Viscosity (kinematic viscosity) can be measured using a capillary viscometer or rotational viscometer based on JIS Z 8803:2011.

[0129] Considering durability, the amount of component (a) added based on the liquid silicone rubber mixture used to form the elastic layer is preferably 50% by volume or more, and 85% by volume or less considering heat transfer, more preferably 60% by volume or more considering durability, and 80% by volume or less considering heat transfer.

[0130] Component (b): Organopolysiloxane containing silicon-bonded active hydrogen

[0131] Organopolysiloxanes containing silicon-bonded active hydrogen act as crosslinking agents, which react with the unsaturated aliphatic groups of component (a) under the action of a catalyst to form cured silicone rubber.

[0132] As component (b), any organopolysiloxane having Si-H bonds can be used. In particular, considering the reactivity with the unsaturated aliphatic groups of component (a), those having an average of more than three hydrogen atoms bonded to silicon atoms per molecule are preferred.

[0133] Specific examples of component (b) include linear organopolysiloxanes represented by formula (3) and cyclic organopolysiloxanes represented by formula (4).

[0134]

[0135] In equation (3), m 2 n is an integer greater than or equal to 0 (preferably 10 to 30). 3 It is an integer greater than or equal to 3 (preferably 5 to 20), and R 5 Each is an independent monovalent unsubstituted or substituted hydrocarbon group that does not have an unsaturated aliphatic group.

[0136]

[0137] In equation (4), m 3 n is an integer greater than or equal to 0 (preferably 10 to 30), n4 is an integer greater than or equal to 3 (preferably 5 to 20), and R 6 Each is an independent monovalent unsubstituted or substituted hydrocarbon group that does not have an unsaturated aliphatic group.

[0138] R can be derived from equations (3) and (4). 5 and R 6 Examples of monovalent unsubstituted or substituted hydrocarbon groups without unsaturated aliphatic groups include those with R in formula (1). 1 The same group. Preferably, R 5 and R 6 Each of them is more than 50% methyl, preferably R 5 and R 6 All are methyl groups because they are easy to synthesize and process, and their excellent heat resistance is readily obtained.

[0139] Component (c): Catalyst

[0140] The catalyst used to form silicone rubber is, for example, a hydrosilylation catalyst used to accelerate the curing reaction. Known substances such as platinum compounds and rhodium compounds can be used as hydrosilylation catalysts. The amount of catalyst added can be appropriately set and is not particularly limited.

[0141] Component (d): Filler

[0142] As described above, the elastic layer contains filler.

[0143] The selection of filler materials takes into account their thermal conductivity, specific heat capacity, density, particle size, dielectric constant, and other factors. Examples of fillers used to improve the thermal transfer properties of inorganic materials, especially metals and metal compounds, include the following: silicon carbide, silicon nitride, boron nitride, aluminum nitride, alumina, zinc oxide, magnesium oxide, silicon dioxide, copper, aluminum, silver, iron, nickel, metallic silicon, and carbon fiber.

[0144] Furthermore, considering the thermal conductivity, resistivity and dielectric constant of the filler itself, fillers A and B are more preferably selected from at least one filler chosen from the group consisting of alumina, zinc oxide, metallic silicon, silicon carbide, boron nitride and magnesium oxide.

[0145] Filler A preferably comprises at least one selected from the group consisting of metallic silicon and boron nitride, and more preferably comprises boron nitride. In particular, filler A preferably comprises boron nitride in a plate shape.

[0146] Based on volume distribution, filler A preferably has a 10% particle size (D10) of 3.0 to 6.0 μm.

[0147] Based on volume distribution, filler A preferably has a 50% particle size (D50) of 4.0 to 8.0 μm.

[0148] Based on volume distribution, filler A preferably has a 90% particle size (D90) of 5.0 to 9.0 μm.

[0149] Filler B may contain, for example, alumina particles.

[0150] Based on volume distribution, filler B preferably has a 10% particle size (D10) of 10.0 to 18.0 μm.

[0151] Based on volume distribution, filler B preferably has a 50% particle size (D50) of 10.0 to 20.0 μm.

[0152] Based on volume distribution, filler B preferably has a 90% particle size (D90) of 10.0 to 25.0 μm.

[0153] In the following, as one embodiment, the corona charging device 2 and the steps of applying an electric field to the elastic layer using the device will be described. The corona charging method includes a non-contact charging method (scorotron method) that provides a grid electrode between the corona wire and the part to be charged, and a corona method that does not provide a grid electrode. Considering the controllability of the surface potential of the part to be charged, the non-contact charging method is preferred.

[0154] like Figure 4A and Figure 4BAs shown, the corona charging device 2 includes a front block 201, a rear block 202, and shielding members 203 and 204. Furthermore, a discharge line 205 is stretched between the front block 201 and the rear block 202, and discharges when a charging bias voltage is applied from a high-voltage power supply, thereby charging the surface of the uncured elastic layer 41c on the substrate, which is the component to be charged.

[0155] Similar to the configuration of a typical corona charging device, a high voltage is applied to the discharge line 205, which serves as a discharge component. Then, by applying a high voltage to the grid 206, the ion current obtained by discharging to the shields 203 and 204 is controlled, and the surface of the elastic layer 41c is controlled to have a desired charging potential. In this case, since the substrate 41b or the core 1 holding the substrate 41b is grounded (not shown), a desired electric field can be generated in the elastic layer 41c by controlling the surface potential of the elastic layer 41c.

[0156] To explain in detail the manufacturing method of the fixing component according to the above embodiment, firstly, an elastic layer comprising silicone rubber containing filler is formed on a substrate. Next, as... Figure 4A As shown, the corona charging device 2 is positioned close to and facing the uncured elastic layer 41c of the fixing member 41 in its width direction. A voltage is then applied to the grid 206 of the corona charging device 2. For example, in a discharge state, the fixing member 41 rotates at 141 rpm for 160 seconds, thus charging the surface of the elastic layer. The distance between the surface of the elastic layer and the grid 206 can be from 1 mm to 10 mm. The surface of the elastic layer 41c is charged in this way, generating an electric field within the elastic layer and orienting the thermally conductive filler. The elastic layer is then cured by heating or the like, fixing the orientation of the filler.

[0157] The voltage applied to the grid 206 is preferably in the absolute range of 0.1 kV to 3 kV (0.2 to 6 kV in Vp-p for AC applications) to generate effective electrostatic interaction in the filler. When using an electric field to orient the filler in the thickness direction of the elastic layer, it is important that an electric field is generated in the thickness direction of the elastic layer 41c. The effect is the same if the sign of the applied voltage is the same as the sign of the voltage applied to the conductor, even if the direction of the electric field is opposite, whether negative or positive.

[0158] Additionally, when performing AC charging to suppress liquid surface flow as described below, it is desirable to match the waveform phase of the wires and the grid. Depending on the type and content of the filler, it may be difficult to orient the filler, and in such cases, it is desirable to increase the voltage applied to the grid 206. This is presumably related to the dielectric constants of the silicone rubber component and the thermally conductive filler. When the difference in dielectric constants between the silicone rubber and the filler is large, or when the content is low, the filler can be oriented with a relatively low applied voltage.

[0159] On the other hand, when the voltage applied to the grid 206 is too high, the electrostatic repulsion caused by the surface charge of the elastic layer increases, leading to liquid surface flow, and the surface properties of the elastic layer 41c may deteriorate. Therefore, the voltage applied to the grid 206 is more preferably in the absolute range of 0.1 kV to 1.5 kV (0.2 to 3 kV in Vp-p in the case of AC applications). This liquid surface flow can be mitigated by AC charging.

[0160] As a construction for controlling the electric potential on the surface of the elastic layer in the longitudinal direction, for example, one could use... Figure 4A The structure shown allows for the charging of the entire elastic layer 41c by rotating the fixing member 41 around its central axis when a voltage is applied to the grid 206. Here, to ensure stable orientation of the filler, the rotation speed of the fixing member is preferably set to 10 rpm to 500 rpm, and the processing time is set to 20 seconds or more. As described above, by controlling the value of the voltage applied to the grid and the duration of the applied electric field, the average orientation angle θ of the filler can be controlled. Ave .

[0161] The discharge wire 205 can be made of stainless steel, nickel, molybdenum, tungsten, etc., but tungsten is preferred because it is an extremely stable metal. Here, the discharge wire stretched inside the shield can have a circular cross-sectional shape or a serrated shape.

[0162] Furthermore, the diameter of the discharge wire 205 is preferably between 40 μm and 100 μm. This is because when the diameter of the discharge wire is within this range, it prevents the discharge wire from being cut by ions during discharge, and also eliminates the need to apply excessively high voltage to generate corona discharge. As the voltage applied to the discharge wire 205, DC voltage or AC voltage can be used. In the case of AC voltage, a frequency of approximately 0.01 Hz to 1,000 Hz is preferred. The voltage can be applied by using an arbitrary waveform generator to output a square wave or a sine wave, etc.

[0163] Surface layer

[0164] The electrophotographic component may have a surface layer 41a on the outer peripheral surface of the elastic layer 41c. The surface layer 41a may be made of a fluoropolymer material with a thickness of 100 μm or less, preferably 10 to 70 μm. For example, the fluoropolymer layer may contain, for example, PTFE, FEP, and PFA, and PFA is preferred considering peelability and rigidity. PFA is a copolymer of perfluoroalkyl vinyl ether (PAVE) and tetrafluoroethylene (TFE).

[0165] Examples of methods for forming a surface layer 41a containing PFA include applying a dispersion solution (aqueous dispersion coating) or powder coating containing PFA as a main component to the surface of the elastic layer 41c and heating it above its melting point to form a film. Alternatively, a method can be exemplified by covering the surface of the elastic layer 41c with a PFA tube produced by separate extrusion molding. The surface layer 41a is, for example, a PFA tube.

[0166] Commercially available PFAs can be used as PFAs. Specific examples include AP-230 (product name, available from Daikin Industries, Ltd.), AP-231SH (product name, available from Daikin Industries, Ltd.) as a PFA with fully fluorinated end groups, and 451 HP-J (product name, available from Chemours-Mitsui Fluoroproducts Co., Ltd.) with small spherulite size.

[0167] Pre-treating the inner surface of surface layer 41a with sodium, excimer laser, ammonia, or plasma etching can improve adhesion. In this example, a PFA tube with a thickness of 20 μm obtained by extrusion molding is used.

[0168] Adhesive layer

[0169] Surface layer 41a can be adhered to the surface of elastic layer 41c via an adhesive layer (not shown) therebetween. When an adhesive layer is provided, adhesion between the elastic layer and the surface layer is easier. The material of the adhesive layer is not particularly limited, and known materials can be used. For example, the adhesive layer preferably contains a cured adhesive product. The adhesive can be a solution-based adhesive or a hot-melt adhesive.

[0170] There are no particular restrictions on the adhesive; any known adhesive can be used, with silicone rubber adhesives being preferred.

[0171] There is no particular limitation on the thickness of the adhesive layer, but it is preferably 1 to 20 μm, and more preferably 3 to 10 μm.

[0172] Electrophotographic image forming equipment

[0173] Figure 1 This is a cross-sectional view of a color electrophotographic printer, an example of an electrophotographic image forming apparatus (hereinafter referred to as "image forming apparatus") according to this embodiment, and is a cross-sectional view in the direction of material transport. In this embodiment, the color electrophotographic printer is simply referred to as a "printer".

[0174] Figure 1The printer 1 shown includes an image forming unit 10 for colors Y (yellow), M (magenta), C (cyan), and Bk (black). A photosensitive drum (photosensitive element) 11 is pre-charged by a charging device 12. The photosensitive drum 11 is then exposed by a laser scanner 13 to form an electrostatic latent image. The electrostatic latent image is developed into a toner image by a developing device 14. The toner image on the photosensitive drum 11 is sequentially transferred to an image carrier, such as an intermediate transfer belt 31, by a primary transfer blade 17. After the transfer, residual toner on the photosensitive drum 11 is removed by a cleaner 15. As a result, the surface of the photosensitive drum 11 is cleaned and ready for the next image formation.

[0175] On the other hand, the recording material P is fed one after another from the paper tray 20 or the multi-feed tray 25 in the direction of arrow 3 to a pair of positioning rollers 23. The pair of positioning rollers 23 first receive the recording material P and straighten it if it is skewed. Then, the pair of positioning rollers 23, synchronized with the toner image on the intermediate transfer belt 31, feed the recording material P between the intermediate transfer belt 31 and the secondary transfer roller 35. The color toner image on the intermediate transfer belt is transferred to the recording material P by, for example, the transfer member of the secondary transfer roller 35. Then, when the recording material P is heated and pressed by the fixing device 40, the toner image on the recording material P is fixed to the recording material.

[0176] The electrophotographic image forming apparatus includes a fixing unit 40. Next, the fixing unit in the electrophotographic image forming apparatus will be described. The fixing unit includes a fixing member and a pressure member disposed opposite to the fixing member. Figure 2 This is a schematic structural diagram of a fixing device 40, which is an example of a film-heated heating device (tensionless type). In this example, this type of heating device is used, but roller-type or film-type heating devices can also be used.

[0177] Reference numeral 43 denotes a ceramic heater (hereinafter referred to as the heater) as a heating element. The heater 43 has a basic structure comprising an elongated thin ceramic substrate with its longitudinal direction perpendicular to the plane of the drawing and a current-applying heating resistance layer disposed on the surface of the substrate. The heater 43 is a low heat capacity heater, and when current is applied to the heating resistance layer, the heater is heated across its entire surface with a rapidly increasing characteristic. Furthermore, the heater is configured to switch the current application area according to the longitudinal width dimension of the recording material.

[0178] The electrophotographic component according to at least one aspect of this disclosure can be used, for example, as a fixing component. The fixing film 41 is a cylindrical (annular) heat-resistant fixing component that serves as a heating element for heat transfer and is loosely fitted onto a support member (heater holder) including a heater 43. The fixing film 41 has... Figure 3The structure shown is a fixing film having a three-layer composite structure including at least a surface layer 41a, an elastic layer 41c, and a substrate 41b.

[0179] The pressure roller 44 is a heat-resistant elastic pressure roller that serves as a pressure member, and has a core and an elastic layer made of heat-resistant rubber such as silicone rubber, fluororubber, or silicone rubber foam. The two ends of the core are arranged such that they are rotatably supported by bearings. Here, an electrophotographic component according to at least one aspect of this disclosure can also be used, for example, as a pressure member. That is, at least one of the fixing component and the pressure member is preferably an electrophotographic component. For example, the pressure member can have the same construction as the fixing film 41, and the pressure member can have a three-layer composite structure comprising a surface layer 41a, an elastic layer 41c, and a substrate 41b.

[0180] The fixing film 41 and the heater 43 are arranged parallel to the pressure roller 44 above the pressure roller 44 and are pressed by a pressing member (not shown). In this way, the lower surface of the heater 43 and the upper surface of the pressure roller 44 press against each other, with the fixing film 41 between them, resisting the elasticity of the elastic layer, and forming a fixing roller gap N with a predetermined width as a heating part.

[0181] The pressure roller 44 is driven by a drive device (not shown) to rotate at a predetermined circumferential speed in the counterclockwise direction indicated by the arrow. The pressure roller 44 is driven to rotate, and a rotational force is applied to the cylindrical fixing film 41 due to the pressure friction at the fixing roller gap N between the pressure roller 44 and the fixing film 41. The fixing film 41 then contacts and slides on the lower surface of the heater 43, and is driven to rotate in the clockwise direction indicated by the arrow. The support member (heater holder) 46 is a rotation guide member for the cylindrical fixing film 41.

[0182] The pressure roller 44 is driven to rotate, and the cylindrical fixing film 41 is driven to rotate accordingly. Current is applied to the heater 43, and the heater rapidly heats up to a predetermined temperature and enters a temperature-regulating state. At this time, the recording material P carrying the unfixed toner image T is introduced into the fixing roller gap N between the fixing film 41 and the pressure roller 44. Then, in the fixing roller gap N, the toner image-carrying side of the recording material P comes into close contact with the outer surface of the fixing film 41 and is clamped and conveyed through the fixing roller gap N together with the fixing film 41. During this clamping and conveying process, the recording material P is heated by the heat from the fixing film 41, which has already been heated by the heater 43, and the unfixed toner image T on the recording material P is heated and pressed onto the recording material P, melting and fixing it. The recording material P, passing through the fixing roller gap N, separates from the surface curvature of the fixing film 41 and is discharged and conveyed.

[0183] The maximum surface pressure of the recording material in the fuser roller gap N in the transport direction is preferably 0.25 to 0.40 MPa, more preferably 0.35 to 0.40 MPa. When the surface pressure in the fuser roller gap increases, the deformation of the toner can be increased, and the image quality can be improved.

[0184] The pressure applied to the fixing roller gap N is measured using a tactile sensor (available from Nitta Corporation). Under measurement conditions, measurements are taken at 0.5 mm intervals in the transport direction and at 2 mm intervals in the direction perpendicular to the transport direction. The maximum surface pressure of the recording material in the fixing roller gap N in the transport direction is the maximum value of the pressure distribution in the transport direction at the center A of the sheet passage area of ​​the roller gap N. Here, center A is the longitudinal center of the sheet passage area of ​​the roller gap N. The sheet passage area of ​​the roller gap N is the area of ​​the roller gap N through which the recording material fixed by the fixing device 40 can pass.

[0185] Reference numeral 45 indicates a contact thermometer (thermometer) that measures the temperature of the fixing film 41 heated by the heater 43 and transmits the detection result to a temperature control unit (not shown). Reference numeral 46 indicates a heater holder, which is a component that keeps the heater 43 heated to a high temperature.

[0186] The method for measuring physical properties in this disclosure is described below.

[0187] Measurement of thermal conductivity of the elastic layer in the thickness direction

[0188] The thermal conductivity λ of the elastic layer in the thickness direction is calculated using the following formula.

[0189] λ=α×C p ×ρ

[0190] In the formula, λ is the thermal conductivity of the elastic layer in the thickness direction (W / (m·K)), and α is the thermal diffusivity in the thickness direction (m). 2 / s), C p ρ is the specific heat at constant pressure (J / (kg·K)), and ρ is the density (kg / m³). 3 Here, the thermal diffusivity α in the thickness direction and the specific heat C under constant pressure are determined by the following methods. p And the value of density ρ.

[0191] Thermal diffusivity α

[0192] The thermal diffusivity α of the elastic layer in the thickness direction was measured at room temperature (25°C) using a periodic heating thermal property measurement device (product name: FTC-1, available from Advance Riko., Inc.). Five sample pieces, each with an area of ​​8 × 12 mm, were prepared by cutting them from the elastic layer using a cutter, and the thickness of each sample piece was measured using a digital length measurement system (product name: DIGIMICRO MF-501, with a φ4 mm planar measuring tip, available from Nikon Corporation). Next, each sample piece was measured a total of five times, and the average value (m) was determined. 2 / s). Here, the measurement is performed while applying pressure to the sample sheet using a weight of 1 kg.

[0193] Specific heat C under constant pressure p

[0194] The specific heat of the elastic layer under constant pressure was measured using a differential scanning calorimeter (product name: Q2000, purchased from TA Instruments).

[0195] Specifically, aluminum discs are used as sample and reference discs. First, for blank measurements, a procedure is performed where both discs are empty and the temperature is kept constant at 15°C for 10 minutes, then increased to 215°C at a rate of 10°C / minute, and then kept constant at 215°C for another 10 minutes.

[0196] Next, 10 mg of synthetic sapphire with a known specific heat at constant pressure was used as a reference material, and measurements were performed using the same procedure. A 10 mg measurement sample, identical in amount to the reference material, was then cut from the elastic layer, placed in a sample pan, and measured using the same procedure. These measurements were analyzed using the specific heat analysis software included with the differential scanning calorimeter, and the specific heat C at constant pressure and 25°C was calculated based on the average of the five measurements. p .

[0197] Density ρ

[0198] The density of the elastic layer was measured using a dry automatic densitometer (product name: AccuPyc II1340, purchased from Shimadzu Corporation).

[0199] Specifically, using 10cm 3A sample cell is constructed by cutting a sample piece from the elastic layer, filling approximately 80% of the cell volume, and placing the sample piece into the sample cell after measuring its mass. This sample cell is positioned within the measurement unit of the apparatus, and its volume is measured 10 times after purging with nitrogen. For each measurement, the density of the elastic layer is calculated from the sample piece's mass and the measured volume, and an average value is obtained.

[0200] The thermal conductivity λ of the elastic layer in the thickness direction is converted to specific heat C under constant pressure. p (J / (kg·K)), density ρ(kg / m³) 3 The measured thermal diffusivity α(m) of the elastic layer 2 Calculated by / s.

[0201] Measurement of filler content

[0202] A 6g sample was collected from the elastic layer and immersed in a silicone solvent (eSolve 21RS, commercially available from Kaneko Chemical Co., Ltd.) to dissolve the silicone rubber and extract the filler. The extracted filler was washed with toluene and dried at 25°C for 1 hour, and the mass of the filler was measured. Next, the density of the filler was measured using a dry automatic densitometer (AccuPyc II1340, purchased from Shimadzu Corporation). The filler content (volume %) of the elastic layer was determined from the mass and density values ​​of the filler contained in the 6g elastic layer obtained in this manner.

[0203] Content V A Content V B Calculation of average aspect ratio

[0204] First, the filler collected during the filler content measurement was dispersed in toluene to prepare a dispersion solution. The dispersion solution was applied to a substrate (aluminum foil) and dried to prepare a sample for observation using a field emission scanning electron microscope (FE-SEM). The concentration of the dispersion solution was adjusted so that the filler particles did not overlap and could be observed individually. Next, the sample was placed on a 45° inclined sample stage, and the filler was observed using an FE-SEM (product name: SU8220, available from Hitachi High-Tech Corporation) under the following conditions.

[0205] SEM observation conditions

[0206] Accelerating voltage: 2.0kV

[0207] WD: 12mm

[0208] Sample tilt angle: 45°, -45°

[0209] Adjust the magnification appropriately according to the size of the packing material.

[0210] By observing under the above conditions, the upper and side surfaces of the sample can be observed. Observation images are obtained for each individual filler, where the entire upper and side surfaces are visible, the major axis d1 and minor axis d2 are determined by the upper surface observation image, and the thickness h is determined by the side surface observation image.

[0211] Method for calculating major axis d1 and minor axis d2

[0212] The image of the upper surface of the filler was binarized using the image analysis software "ImageJ," making the filler portion appear white and the non-filler portion black. The filler was then roughly elliptical, and its major axis d1 and minor axis d2 were determined. Specifically, the user first selected Analyze-Set Scale in ImageJ and used the scale bar in the SEM observation condition display cell to set the actual length per pixel.

[0213] Next, the user selects an image adjustment threshold and specifies a brightness threshold so that only the filled portion is selected. Then, the user selects Analyze-Set Measurements, checks the fitted ellipse, selects Analyze-Analyze Particles, and sets the major value of the output to the major axis d1 of the filler and the minor value to the minor axis d2 of the filler.

[0214] Methods for calculating thickness h

[0215] For observation images of the side surface of the filler, the height of the filler from the substrate surface of the observed sample is defined as the thickness h.

[0216] As described above, the major axis d1, minor axis d2, and thickness h are determined, and the volume V of the packing is calculated using the following formula. f and particle size R f Furthermore, the larger of the values ​​obtained by dividing d1 by d2 or h for each type of packing is defined as the aspect ratio of the packing.

[0217] Volume V f =3.14×d1 / 2×d2 / 2×h

[0218] Particle size R f =(V f ×6 / 3.14) 1 / 3

[0219] V was measured in 100 packing materials. f Rf And aspect ratio, particle size R f Fillers with a particle size greater than 3μm and less than 10μm are defined as filler A, and particle size R f Packing material with a diameter of 10 to 40 μm is defined as packing material B. The total volume V of packing material A is determined. f The total volume V of packing B f and the volume V of all packing f The sum of V, and V is calculated by the following formula. A and V B .

[0220] V A =(filler content (volume %)) × (total volume of filler A, V) f ) / V

[0221] V B =(filler content (volume %)) × (total volume of filler B, V) f ) / V

[0222] Furthermore, the arithmetic mean of the aspect ratios of packing A and packing B is determined and used as the average aspect ratio of packing A and packing B. Additionally, the volume V of 100 packings is... f By increasing the volume V of packing A f and the volume V of packing B f The sum divided by the total volume V of all packing materials f The sum of V is used to calculate the value V. A+B .

[0223] The average orientation angle θ of the packing Ave Calculation

[0224] The average orientation angle θ of the filler was calculated by image analysis using a binarized image obtained from a cross-sectional image of the elastic layer. Ave Details are as follows.

[0225] Prepare a cross section for measurement.

[0226] like Figure 5 As shown, the plane of the fixing member 41, which is an electrophotographic component, in the thickness direction-circumferential direction is defined as the first plane, and the planes that rotate from the first plane in increments of 10° toward the thickness direction-axial direction of the fixing member 1 are defined as the second to tenth planes.

[0227] like Figure 6As shown, the fixing member 41 is cut into circular slices with a width of 500 μm or more in the axial direction to pass through the midpoint of the fixing member 41, and then cut in the axial direction to obtain a strip sample. Then, the strip sample is divided into 10 equal regions in the circumferential direction, and cross sections with a length of 500 μm or more are cut from each region, such that they are parallel to the first to tenth planes of the fixing member 1 and pass through the midpoint of the fixing member in the axial direction, and are defined as the first to tenth cross sections.

[0228] When cutting the cross-section, a sharp pair of scissors is used to obtain a cross-sectional sample. Then, a cross-section forming method using an ion beam is employed. Using an ion beam cross-section forming method prevents filler detachment and contamination from excess components such as polishing agents, which often occur during the cross-section polishing process, and results in a cross-section with minimal polishing marks. A cross-section polishing machine (IM4000+, commercially available from Hitachi High Tech Corporation) is used for the ion beam cross-section forming process.

[0229] Observation and binarization of cross-sectional images

[0230] Next, the obtained cross-section was observed using a laser microscope (OPTELICS H1200, commercially available from Lasertec Corporation), and after automatic adjustment of contrast and brightness, a cross-sectional image was obtained showing the entire area covering the elastic layer in the thickness direction × a 500 μm area covering the area perpendicular to the thickness direction. In this case, the midpoint at 500 μm perpendicular to the thickness direction was matched with the midpoint of the fixing member in the axial direction.

[0231] The acquired image was binarized using commercially available image analysis software, making the filler areas appear white and the silicone rubber areas appear black. ImageJ was used as the image analysis software for binarization, making the filler areas white and the non-filler areas black. Specifically, the user selected Analysis - Set Scale in ImageJ and used the scale bar in the image to set the actual length of each pixel. The user then selected Image Adjust Brightness / Contrast and pressed Auto for automatic adjustment of contrast and brightness. If the automatic adjustment was ineffective, manual adjustment was performed. Next, the user selected Image Adjust Threshold, chose Otsu as the thresholding method, and performed binarization. The image used for analysis was selected to display as much of the elastic layer as possible.

[0232] θ Ave Calculation

[0233] Each filler in the obtained 10 cross-sectional binarized images is approximately an ellipse, and the major axis a, minor axis b, and angle θ (called the filler orientation angle) formed by the major axis of the ellipse relative to the thickness direction of the elastic layer are calculated using image analysis software. Specifically, after obtaining the binarized image in ImageJ as described above, the user selects Analyze-Set Measurements, checks the Fit ellipse, selects Analyze-Analyze Particles, and sets the major value of the output to the major axis a of the filler, the minor value to the minor axis b of the filler, and the angle value to θ.

[0234] In this case, when the major axis of the approximately elliptical packing is parallel to the thickness direction of the elastic layer, the packing orientation angle θ is defined as 0°; when the major axis of the packing is perpendicular to the thickness direction of the elastic layer, θ is defined as 90°, and this value is converted to make the range of θ from 0 to 90°. Therefore, as the packing orientation angle is closer to 0°, the packing is more strongly oriented in the thickness direction.

[0235] Using the major and minor axis lengths of the ellipse calculated from 10 cross-sectional images, the value of major axis length a / minor axis length b was calculated, and data was extracted only for fillers where the value of major axis length a / minor axis length b was 2.0 or higher. The average orientation angle θ of all orientation angles θ of fillers with a major axis length / minor axis length of 2.0 or higher extracted from the 10 cross-sectional images was defined as the average orientation angle θ of the filler relative to the thickness direction of the elastic layer. Ave .

[0236] Measurement of elastic layer thickness

[0237] When calculating the average orientation angle θ of the filler Ave The thickness of the elastic layer was calculated using cross-sectional images of the first to tenth sections obtained at the time. The arithmetic mean of the 10 sections was used.

[0238] Measurement of the elastic modulus of the elastic layer

[0239] The tensile modulus of elasticity is measured by the following method and is used as the modulus of elasticity of the elastic layer.

[0240] Sample pieces were cut from the elastic layer using a stamping die (such as dumbbell type 8 as specified in JIS K 6251:2004), and the thickness near the center was measured, which was the measurement point. Next, the cut sample pieces were tested at room temperature at a tensile speed of 200 mm / min using a precision general-purpose testing machine (product name: Autograph AG-X, commercially available from Shimadzu Corporation). A graph was created from the measurement results, where the horizontal axis represents the strain of the sample piece and the vertical axis represents the tensile stress, and the tensile modulus of elasticity is defined as the slope obtained by approximating the linearity of the measurement data within the strain range of 0 to 10%. The arithmetic mean of 10 sample pieces was used.

[0241] Example

[0242] The present disclosure will now be described in more detail with reference to embodiments and comparative examples, but aspects of the present disclosure are not limited thereto.

[0243] Grading treatment of packing

[0244] Spherical alumina particles (product name: DAM-10: available commercially from Denka Co., Ltd.), flat boron nitride particles (product name: GP: available commercially from Denka Co., Ltd., MGP: available commercially from Denka Co., Ltd.), and metallic silicon (product name: #200 WB: available commercially from Kinsei Matec Co., Ltd., Fine: available commercially from Kinsei Matec Co., Ltd.) are used as raw materials to classify or spheroidize the fillers to obtain fillers 1 to 10 with desired particle size distribution and aspect ratio.

[0245] The grading process is carried out using an inertial grading type elbow jet (available from Nittsu Mining Co., Ltd.) with a feed rate of 5 kg / hr, and the F grading edge (fine powder grading edge) and G grading edge (coarse powder grading edge) are adjusted to obtain the desired particle size distribution.

[0246] The spheroidization process is performed using a multifunctional particle design device faculty (available from Hosokawa Micron Corporation), and the rotational speeds of the dispersing unit and the grading unit are adjusted to obtain the desired aspect ratio and particle size distribution.

[0247] For the obtained packing materials 1 to 10, the values ​​are compared with the calculated V. A V BUsing the same method as the average aspect ratio, determine the V of 100 packings. f and R f The values ​​for 50% particle size (D50), 10% particle size (D10), and 90% particle size (D90) based on volume distribution were calculated. Table 1 shows the raw materials and D50, D10, and D90 for fillers 1 to 10.

[0248] Example 1

[0249] In this embodiment, preparation as follows Figure 3 The fixing film shown.

[0250] Substrate

[0251] SUS with an inner diameter of 24 mm and a thickness of 30 μm is used as the substrate. Specifically, an SUS ring-shaped tape with an inner diameter of 24 mm, a width of 400 mm, and a thickness of 30 μm is used as the substrate. Here, the ring-shaped tape with a core inserted therein is processed during a series of production steps.

[0252] Formation of inner sliding layer

[0253] First, approximately equimolar amounts of an aromatic tetracarboxylic dianhydride or its derivative and an aromatic diamine are reacted in an aprotic polar organic solvent to obtain a polyimide precursor solution. The obtained polyimide precursor solution is applied to the inner circumferential surface of a substrate using a ring coating method. The solvent is dried in an electric furnace, and then heated at 260–400 °C for approximately 1 hour to form an inner sliding layer. The thickness of the inner sliding layer is 12 μm.

[0254] Preparation of silicone rubber mixture

[0255] Liquid addition-cured silicone rubber mixtures are prepared by mixing the following components (a) through (d) using the following procedure.

[0256] Component (a): A linear organopolysiloxane with unsaturated aliphatic groups

[0257] Component (b): Organopolysiloxane containing silicon-bonded active hydrogen

[0258] Component (c): Catalyst

[0259] Component (d): Filler

[0260] First, prepare 100 parts by weight of an organosilicon polymer as component (a). This organosilicon polymer has vinyl groups as unsaturated aliphatic groups only at both ends of its molecular chain and methyl groups as unsubstituted hydrocarbon groups that do not contain other unsaturated aliphatic groups. This organosilicon polymer (product name: DMS-V35, purchased from Gelest, viscosity 5,000 mm) 2 / s) will be referred to as "Vi" in the following text.

[0261] Next, 98.7 parts by weight of packing 3 and 43.9 parts by weight of packing 10 were added to Vi as component (d), and the mixture was placed in a planetary centrifugal mixer (available from Thinky Corporation, ARV-5000) and stirred at 600 rpm for 2 minutes to obtain mixture 1.

[0262] Next, mixture 2 will be obtained by adding a solution obtained by dissolving 0.2 parts by weight of 1-ethynyl-1-cyclohexanol (commercially available from Tokyo Chemical Industry Co., Ltd.) as a curing inhibitor in an equal weight of toluene to mixture 1.

[0263] Next, 0.1 parts by mass of the hydrogenation silylation catalyst (a mixture of 1,3-divinyltetramethyldisiloxane platinum complex, 1,3-divinyltetramethyldisiloxane and 2-propanol) as component (c) is added to mixture 2 to obtain mixture 3.

[0264] In addition, weigh 1.3 parts by weight of an organosilicon polymer (product name: HMS-301, purchased from Gelest, viscosity 30 mm) that has only a linear siloxane backbone and silicon-bonded active hydrogen groups on its side chains. 2 / s (hereinafter referred to as "SiH") is used as component (b). It is added to mixture 3 and mixed thoroughly to obtain a liquid addition-cured silicone rubber mixture.

[0265] Formation of primer layer and elastic layer

[0266] The following procedure is used to form a primer layer and an elastic layer on a substrate on which an inner sliding layer is formed.

[0267] A hydrosilane-based silicone primer (DY39-051 A / B; commercially available from Dow Toray Co., Ltd.) was applied almost uniformly to the outer peripheral surface of the substrate to a dry weight of 20 mg. The solvent was dried, and the substrate was then fired in an electric furnace set at 160°C for 30 minutes.

[0268] A silicone rubber compound is applied to a primer-treated substrate at a thickness of 250 μm using a ring coating method. This is referred to as an uncured ring band.

[0269] Next, a corona charging device with a charging area width of 295 mm was positioned opposite the busbar of the uncured annular strip, and an AC electric field was applied to the surface of the uncured elastic layer while the uncured annular strip was rotated at 100 rpm. The conditions were as follows: current supplied to the discharge line of the corona charging device: ±150 μA, voltage applied to the grid: ±1,500 V (Vp: 3,000 V), frequency: 0.025 Hz, charging time: 160 seconds, and distance between the grid electrode and the strip: 3 mm.

[0270] The charged, uncured annular strip is heated in an electric furnace at 160°C for 1 minute (first curing), and then heated in an electric furnace at 200°C for 30 minutes (second curing) to cure the silicone rubber mixture, thereby obtaining an annular strip with a cured elastic layer.

[0271] Coating of adhesive layer

[0272] An addition-curing silicone rubber adhesive (product name: SE1819CV A / B; commercially available from Dow Corning Toray Co., Ltd.) was applied almost uniformly as an adhesive layer to the surface of the cured elastic layer of the annular strip, with a thickness of approximately 10 μm.

[0273] Surface layer formation

[0274] After applying the adhesive, PFA (product name: AP-231SH; commercially available from Daikin Industries, Ltd.) is extruded and molded to form a surface layer with an inner diameter of 23 mm and a thickness of 20 μm, and the inner surface is etched to obtain a fluoropolymer tube. The adhesive is then coated onto the fluoropolymer tube by vacuum expansion and external covering (vacuum expansion coating method). The surface of the strip is then rubbed uniformly from above the fluoropolymer tube, thus extruding excess adhesive between the elastic layer and the fluoropolymer tube until the thickness is reduced to approximately 5 μm.

[0275] The annular strip is heated in an electric furnace set to 200°C for 1 hour to cure the adhesive, thus fixing the fluoropolymer tube to the elastic layer.

[0276] The two ends of the resulting annular strip are cut to obtain a fixing film with a width of 336.5 mm.

[0277] The thermal conductivity λ of the elastic layer and the filler content V in the thickness direction of the prepared fixing film were measured. A V B The average aspect ratio θ of fillers A and B Ave The thickness of the elastic layer and the value of the elastic modulus of the elastic layer. Furthermore, by adjusting the V values ​​of fillers A and B... f The sum divided by the V of all packings fThe sum V is used to calculate the value V. A+B Furthermore, durability was evaluated based on the following assessment methods. These results are shown in Table 2.

[0278] Durability

[0279] Based on the following evaluations, use Figure 2 The durability of the film-heated fixing device 40 shown is evaluated. The film-heated fixing device 40 includes the prepared fixing film.

[0280] First, the dimensions of the contact area between the fixing film and the pressure roller are set to 10 mm in the conveying direction and 330 mm in the direction perpendicular to the conveying direction. Then, the profile of the pressure distribution in the conveying direction of the fixing roller gap N is set such that the maximum surface pressure of the recording material in the fixing roller gap N in the conveying direction is 0.35 MPa.

[0281] Then, the evaluation is conducted under the following conditions.

[0282] Test environment: Room temperature 23 degrees Celsius, humidity 50%.

[0283] Processing speed: 200mm / second

[0284] Printing speed: 30 pages / minute

[0285] The surface temperature of the fixing film sheet is 170℃.

[0286] Sheet passing conditions: Sheets (A4-dimensional horizontal, GF-C068) pass continuously.

[0287] If the evaluation result is A to C based on the following evaluation criteria, then the effect of this disclosure has been achieved.

[0288] Evaluation criteria

[0289] A: The elastic layer will not break even after passing through more than 400,000 sheets.

[0290] B: The elastic layer will not break even after passing through more than 300,000 but less than 400,000 sheets.

[0291] C: The elastic layer will not break even after passing through more than 250,000 but less than 300,000 sheets.

[0292] D: The elastic layer breaks after fewer than 250,000 sheets.

[0293] Examples 2 to 16 and Comparative Examples 1 to 8

[0294] Except for the type of filler used, the amount of filler added, and the voltage applied to the grid being changed to those shown in Table 2, the fixing films of Examples 2 to 16 and Comparative Examples 1 to 8 were obtained in the same manner as in Example 1.

[0295] In Examples 2 to 16 and Comparative Examples 1 to 8, the thermal conductivity λ in the thickness direction of the elastic layer of the prepared fixing film and the filler content V were measured. A V B The average aspect ratio θ of fillers A and B Ave The thickness of the elastic layer and the value of the elastic modulus of the elastic layer. Furthermore, by adjusting the V values ​​of fillers A and B... f The sum divided by the V of all packings f The sum V is used to calculate the value V. A+B Furthermore, durability was evaluated using the same evaluation method as in Example 1. These results are shown in Table 2.

[0296] [Table 1]

[0297]

[0298] [Table 2]

[0299]

[0300] In the table, CE represents "Comparative Example," "parts" of filler indicates "amount added [parts by mass]," and voltage is the voltage applied to the grid. "Th" indicates "Thickness of the elastic layer." Filler quantity is the filler content in the elastic layer. "vol.%" indicates volume percentage. arA is the average aspect ratio of filler A, and arB is the average aspect ratio of filler B. "EM" indicates "Elastic Modulus of the Elastic Layer," "TC" indicates "Thermal Conductivity," and "Dur" indicates "Durability Evaluation."

[0301] According to this disclosure, an electrophotographic component with high thermal conductivity and high durability can be provided, wherein the elastic layer is unlikely to break even after long-term use under conditions where the maximum surface pressure at the fixing roller gap is higher than in the past. Furthermore, according to this disclosure, a fixing apparatus and an electrophotographic image forming apparatus including the electrophotographic component can be provided.

[0302] Although this disclosure has been described with reference to embodiments, it should be understood that this disclosure is not limited to the disclosed embodiments. The scope of the appended claims should be given the broadest interpretation to cover all such modifications and equivalent structures and functions.

Claims

1. An electrophotographic component, comprising a substrate and an elastic layer disposed on the outer periphery of the substrate, a rotating component. The elastic layer comprises rubber and fillers dispersed in the rubber. The filler content in the elastic layer is from 15% to 50% by volume. In the packing material, packing material with a particle size of 3 μm or larger and less than 10 μm is defined as packing material A, and When fillers with particle sizes of 10μm to 40μm are defined as filler B, The content V of filler A in the elastic layer A 7 to 30% by volume The average aspect ratio of the filler A is 3.0 to 40.

0. The content V of filler B in the elastic layer B 7 to 30% by volume The average aspect ratio of the filler B is 1.0 to 2.

0. When the plane of the elastic layer in the thickness-circumferential direction is defined as the first plane, and the planes rotated from the first plane in increments of 10° toward the plane of the elastic layer in the thickness-axial direction are defined as the second to tenth planes, Cross-sectional images with dimensions corresponding to the full thickness of the elastic layer × 500 μm are obtained as first to tenth cross-sectional images, such that each image is parallel to the first to tenth planes, and its center in a direction perpendicular to the thickness direction of the elastic layer matches the center of the electrophotographic component in the axial direction. The first to tenth cross-sectional images are binarized to form the first to tenth binarized images, and In the first to the tenth binarized images, when the shape of the filler is approximately elliptical, The filler, which is approximately elliptical and has a major axis length / minor axis length ratio of 2.0 or greater, has an average orientation angle θ of 0° to 45° relative to the thickness direction of the elastic layer. Ave .

2. The electrophotographic component according to claim 1, wherein the filler A comprises a flat plate-shaped filler.

3. The electrophotographic component according to claim 1 or 2, wherein the average orientation angle θ Ave The range is from 0° to 40°.

4. The electrophotographic component according to claim 1 or 2, wherein the average aspect ratio of the filler A is 5.0 to 40.

0.

5. The electrophotographic component according to claim 1 or 2, The filler content in the elastic layer is 25% to 45% by volume. The content V A From 12% to 25% by volume, and The content V B It ranges from 12% to 25% by volume.

6. The electrophotographic component according to claim 1 or 2, wherein, The thermal conductivity of the elastic layer in the thickness direction is 1.40 W / (m·K) or higher.

7. The electrophotographic component according to claim 1 or 2, wherein the filler A comprises boron nitride in a flat plate shape.

8. The electrophotographic component according to claim 1 or 2, wherein the elastic modulus of the elastic layer is from 0.60 MPa to 2.00 MPa.

9. The electrophotographic component according to claim 1 or 2, wherein the thickness of the elastic layer is from 150 μm to 500 μm.

10. The electrophotographic component according to claim 1 or 2, wherein the electrophotographic component is a fixing component.

11. A fixing device, comprising: Fixing components; and A pressure member, facing the fixing member and forming a fixing roller gap between the pressure member and the fixing member, clamps and conveys recording material carrying toner images through the fixing roller gap. At least one of the fixing member and the pressurizing member is an electrophotographic member according to any one of claims 1 to 9.

12. The fixing apparatus according to claim 11, wherein the maximum surface pressure of the recording material in the fixing roller gap in the transport direction is 0.25 MPa to 0.40 MPa.

13. An electrophotographic image forming apparatus, comprising a fixing device, in, The fixing device is the fixing device according to claim 11 or 12.

Images