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 fillers being present in the elastic layer at a content of 15 to 50% by volume, and wherein large-particle-size fillers are defined as filler A and small-particle-size fillers are defined as filler B; the content of filler A in the elastic layer is V. 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 5.0 to 40.0. B The filler B has an average aspect ratio of 1.0 to 2.0, and the average orientation angle θ of the filler has a specific aspect ratio, ranging from 7% to 30% by volume. Ave The range is from 0° to 45°.

Description

Technical Field

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

[0002] Electrophotographic components, such as those used in fixing devices for electrophotographic image forming equipment (e.g., printers, copiers, and fax machines), have a film shape or a roller shape. As a fixing component, 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 a heat-resistant resin or metal, as needed. To ensure the elastic layer exhibits high thermal conductivity, it is preferable to use a material in which an inorganic filler with high thermal conductivity is added as a filler to the rubber, such as silicone rubber.

[0003] In recent years, there has been a demand for additional performance improvements in electrophotographic image forming equipment, such as faster printing speeds, higher image quality, energy efficiency, and support for a wide variety 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 of the fixing component.

[0004] However, when the amount of filler added to the elastic layer is increased to improve its 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 having an elastic layer comprising small-particle-size fillers arranged in the thickness direction of the elastic layer and large-particle-size fillers not arranged 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 arranged in the thickness direction to form a heat conduction path, thermal conductivity can be improved compared to when the filler is not arranged in the thickness direction. However, to obtain higher thermal conductivity, the filler content needs to be increased to a certain level, and balancing thermal conductivity and durability is a problem.

[0008] Therefore, compared to using fillers with a low aspect ratio, when fillers with a high aspect ratio are oriented in the thickness direction of the elastic layer to form a thermally conductive path (such as the second filler in Japanese Patent Application Publication No. 2020-194156), high thermal conductivity can be obtained with a smaller 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 in the fixing device in the fixing roller gap increases, there is a problem of balancing 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, this disclosure 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] When in packing, packing material with a particle size of 10 to 40 μm is defined as packing material A, and

[0015] Fillers with a particle size of 3μm or larger but less than 10μm 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 5.0 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 toward the plane of the elastic layer in the thickness-axial direction in increments of 10° 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 each image is parallel to the first to tenth planes, and its center in the direction perpendicular to the thickness direction of the elastic layer coincides with the center of the electron imaging component in the axial direction.

[0022] The first to tenth cross-sectional images 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 approximated as an ellipse,

[0024] Fillers that are approximately elliptical and have a major axis length / minor axis length ratio of 3.0 or greater have 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. Recording material carrying the toner image is held and transported through the fixing roller gap.

[0028] Among them, 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] 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, this disclosure provides a fixing apparatus and an electrophotographic image forming apparatus including this electrophotographic component. The features of this disclosure will become apparent from the following description of embodiments with reference to the accompanying drawings. The following description of embodiments is provided by way of example. Attached Figure Description

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

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

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

[0035] Figure 4A and Figure 4B These are top and cross-sectional views of the corona charging device.

[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

[0038] In this disclosure, unless otherwise stated, the description of a numerical range, "from XX to YY" or "XX to YY," means a numerical range that includes both a lower limit and an upper limit as endpoints. Furthermore, when a numerical range is described in a hierarchical manner, the upper and lower limits of each numerical range can be arbitrarily combined. Additionally, in this disclosure, descriptions such as "at least one selected from the group consisting of XX, YY, and ZZ" mean any of XX, YY, and 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 still a problem in balancing thermal conductivity and durability. The inventors speculate the reason is as follows.

[0041] When stress is applied to the elastic layer, stress concentration and microcracks may occur near the filler due to its restriction on rubber deformation. Since severe stress concentration also occurs near these microcracks, if many microcracks form 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, this phenomenon is believed to occur when the elastic layer fractures after prolonged use of the fixing component.

[0042] In this scenario, as the aspect ratio of the packing material increases and the particle size becomes larger, stress concentration near the front end of the packing material becomes more severe. Furthermore, stress concentration intensifies 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 within 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, generating numerous microcracks in the elastic layer. Therefore, it is believed that the elastic layer will fracture after long-term use, leading to durability issues.

[0044] The inventors have conducted extensive research and discovered that the following structure 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] When in packing, packing material with a particle size of 10 to 40 μm is defined as packing material A, and

[0049] Fillers with a particle size of 3μm or larger but less than 10μm 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 5.0 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 toward the plane of the elastic layer in the thickness-axial direction in increments of 10° 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 each image is parallel to the first to tenth planes, and its center in the direction perpendicular to the thickness direction of the elastic layer coincides 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 approximated as an ellipse,

[0058] Fillers that are approximately elliptical and have a major axis length / minor axis length ratio of 3.0 or greater have 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 large particle size and a large aspect ratio and filler B having a small particle size and a small aspect ratio, and through the form of filler present within the elastic layer, will be described below.

[0060] First, considering thermal conductivity, it is necessary to include 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 transfer is effective in the orientation direction of the filler, and thermal conductivity in the thickness direction can be increased without excessively increasing the total amount of filler. 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 When the setting is equal to or greater than the lower limit, the aspect ratio of filler A is set to 5.0 or higher, and the average value of the orientation angle θ is [not specified]. Ave Within the above range, thermal conductivity becomes good.

[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 combination of adjacent fillers with large and small particle sizes and reducing the possibility of stress concentration is required.

[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 large strain is applied to the elastic layer, the stress is dispersed throughout the matrix, and the occurrence of cracks can be minimized, thus achieving 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 leading to the fracture of the elastic layer. Therefore, the occurrence of numerous microcracks within the elastic layer results in reduced durability, necessitating the selection of filler combinations that can reduce the frequency of microcrack occurrence to improve durability.

[0065] Regarding stress concentration leading to microcracks, as the particle size of the packing becomes larger, the deformation of the matrix becomes more restricted, resulting in greater stress concentration. Furthermore, the stress concentration is even greater when the curvature of the close-to-close packing tips is smaller. Therefore, the combination of adjacent packings that leads to the maximum stress concentration is the combination of large-diameter and high aspect ratio packings, while the second-maximum stress concentration occurs in the combination of large-diameter and high aspect ratio packings with small-diameter and high aspect ratio packings.

[0066] The inventors have discovered that even when using large-diameter and high aspect ratio fillers, microcracks can be suppressed by combining them with small-diameter and low aspect ratio fillers. Since large-diameter and high aspect ratio fillers exist in a relatively low number within the elastic layer, it is believed that the frequency of microcrack occurrence can be significantly reduced by using a combination of small-diameter and low aspect ratio fillers. Therefore, considering durability, it is important to adjust the filler content V... A and V B Set to be equal to or lower than the above upper limit, and control the aspect ratio of packing A and packing B.

[0067] As described above, by combining large-diameter and high aspect ratio fillers with small-diameter and low aspect ratio fillers, controlling the content of these fillers, and further controlling the orientation of the high aspect ratio fillers, electrophotographic components with thermal conductivity and durability can be obtained. The requirements will be described below.

[0068] 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 is 15% to 50% by volume. When the filler content is above 15% by volume, the elastic layer can achieve high thermal conductivity and good fixing properties. When the filler content is below 50% by volume, sufficient spacing between the fillers can be maintained. Therefore, when large stresses are applied to the elastic layer, the occurrence of microcracks in the elastic layer due to stress concentration between adjacent fillers can be minimized, resulting in excellent durability.

[0069] The filler content in the elastic layer is preferably 18 to 42% by volume, more preferably 20 to 40% by volume, and still more preferably 25 to 35% by volume.

[0070] In the packing, packing with a particle size of 10 to 40 μm is defined as packing A, and packing with a particle size of 3 μm or more but less than 10 μm is defined as packing B.

[0071] 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 5.0 to 40.0. Furthermore, the content of filler B in the elastic layer is V... B The volume percentage is 7% to 30%, and the average aspect ratio of packing B is 1.0 to 2.0.

[0072] When V A 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 5.0 or greater, 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.

[0073] 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 30% or less by volume. Furthermore, excellent durability is achieved when the average aspect ratio of filler B is 2.0 or less.

[0074] To further improve thermal conductivity and durability, V A Preferably, it is 10 to 20% by volume, more preferably 13 to 20% by volume. The average aspect ratio of filler A is preferably 10.0 to 40.0, more preferably 10.0 to 30.0, and still more preferably 13.0 to 20.0. V B Preferably, it is 10 to 20% by volume, more preferably 13 to 20% by volume. The average aspect ratio of filler B is preferably 1.0 to 1.5, more preferably 1.0 to 1.2, still more preferably 1.0 to 1.1, and even more preferably 1.00 to 1.04.

[0075] To further improve thermal conductivity and durability, packing A preferably comprises flat-shaped packing, more preferably flat-shaped packing. Packing B preferably comprises spherical or near-spherical packing with an aspect ratio of 1.0 to 2.0.

[0076] 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+BIt is the total proportion of filler A and filler B in the filler contained in the elastic layer.

[0077] V A+B For example, it is 0.80 or higher, preferably 0.90 or higher, more preferably 0.95 or higher, and still more preferably 0.97 or higher. V A+B There is no specific upper limit for V. A+B For example, it is 0.80 to 1.00, preferably 0.90 to 1.00, more preferably 0.95 to 1.00, and still more preferably 0.97 to 0.99.

[0078] V A / V B The value is, for example, 0.4 to 3.0, preferably 0.5 to 2.0, more preferably 0.6 to 1.5, and still more preferably 0.8 to 1.3. Within the above range, thermal conductivity and durability are more easily achieved.

[0079] 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.

[0080] 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 electron imaging component in the direction perpendicular to the thickness direction of the elastic layer coincides with the center of the electron imaging component in the axial direction.

[0081] 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.

[0082] Fillers that are approximately elliptical and have a major axis length / minor axis length ratio of 3.0 or greater 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.

[0083] θ Ave Preferably, the angle is 0° to 40°, more preferably 0° to 30°, and still more preferably 0° to 25°. A smaller lower limit is preferred, and although there are no particular limitations, θ AveThe angle is preferably 10° to 40°, and can be 12° to 30° or 15° to 25°.

[0084] Average orientation angle θ of the filler Ave Preferably, this is controlled, for example, by applying an electric field to the elastic layer, a step which will be described below.

[0085] <Electronic photographic components>

[0086] 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 need, other layers may be disposed between the substrate, the elastic layer, and the surface layer, on the inner peripheral surface of the substrate, and on the outer peripheral surface of the surface layer.

[0087] 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 with release properties 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). Furthermore, the substrate 41b may have an inner sliding layer (not shown) on its inner peripheral side.

[0088] Each layer will be described in detail below.

[0089] <Substrate>

[0090] The material of the substrate 41b is not particularly limited, and any material known as an electrophotographic component can be used. For example, metals and alloys such as aluminum, iron, stainless steel (SUS), and nickel, as well as heat-resistant resins such as polyimide, can be used. 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.

[0091] 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.

[0092] 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 for the primer treatment can be, for example, a coating in which a silane coupling agent, an organosilicon polymer, a hydrogenated methylsiloxane, an alkoxysilane, a reaction accelerating catalyst, and a colorant such as red iron oxide are appropriately added and dispersed in an organic solvent.

[0093] 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. In particular, when the elastic layer 41c contains a large number of unsaturated aliphatic groups, a primer containing hydrosilyl groups is preferred to impart adhesion through reaction with the unsaturated aliphatic groups. When the elastic layer 41c contains a large number of hydrosilyl groups, a primer containing unsaturated aliphatic groups is preferred.

[0094] 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 be bonded to the elastic layer 41c) and drying or calcining the primer.

[0095] <Inner Sliding Layer>

[0096] An inner sliding layer can be disposed on the inner circumferential surface side 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 the 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.

[0097] <Elastic Layer>

[0098] The elastic layer 41c is used to impart flexibility to the electrophotographic component to ensure the gap of the fixing rollers 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 follow the contours of the paper.

[0099] 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 it 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.

[0100] The elastic modulus of the elastic layer 41c is preferably from 0.60 to 2.00 MPa, more preferably from 0.65 to 1.20 MPa, and still more preferably from 0.70 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.

[0101] 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.

[0102] 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 still more preferably 200 to 300 μm.

[0103] Considering good 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 in the thickness direction is preferred for the elastic layer, and there is no particular upper limit, but examples include 1.25 to 2.50 W / (m·K), 1.40 to 2.00 W / (m·K), and 1.50 to 2.00 W / (m·K).

[0104] 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, as the raw material for the silicone rubber, an addition-curing liquid silicone rubber is preferably used. 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.

[0105] 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.

[0106] The matrix serves to enable the elastic layer to exhibit elasticity. The matrix preferably contains silicone rubber to provide the elastic layer's functionality. Silicone rubber is preferred because it has high heat resistance and maintains its flexibility even in environments with temperatures reaching approximately 240°C in non-paper-covered areas. For example, a cured product of an addition-curing liquid silicone rubber described below can be used as the silicone rubber.

[0107] Liquid silicone rubber blends typically contain the following components (a) to (d).

[0108] Component (a): Organopolysiloxane having unsaturated aliphatic groups;

[0109] Component (b): Organopolysiloxane containing silicon-bonded active hydrogen;

[0110] Component (c): Catalyst;

[0111] Component (d): Filler.

[0112] The components will be described below.

[0113] Component (a): Organopolysiloxane with unsaturated aliphatic groups

[0114] The organopolysiloxane having unsaturated aliphatic groups is an organopolysiloxane having unsaturated aliphatic groups such as vinyl groups, and for example, is selected from at least one of the groups consisting of compounds represented by formula (1) and compounds represented by formula (2). The organopolysiloxane having unsaturated aliphatic groups is preferably linear.

[0115]

[0116] 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 of 3 or higher (preferably 10 to 40). Furthermore, in structure (1), R... 1 Each is an independent 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.

[0117]

[0118] In equation (2), n 2 R is a positive integer (preferably 500 to 1,100). 3 Each is an independent 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.

[0119] 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.

[0120] Unsubstituted hydrocarbon groups

[0121] Alkyl groups (e.g., methyl, ethyl, propyl, butyl, pentyl, hexyl).

[0122] Aryl (e.g., phenyl).

[0123] • Substituted hydrocarbon group

[0124] Substituted alkyl groups (e.g., chloromethyl, 3-chloropropyl, 3,3,3-trifluoropropyl, 3-cyanopropyl, 3-methoxypropyl).

[0125] The organopolysiloxanes represented by formulas (1) and (2) have at least one methyl group directly bonded to a silicon atom forming the chain structure. However, for ease of synthesis and processing, it is preferred that R... 1 and R 3 Each of them is more than 50% methyl, and more preferably, R 1 and R 3 All are methyl groups.

[0126] Furthermore, 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 All are vinyl, because they are easy to synthesize and process and are inexpensive, and they readily undergo cross-linking reactions.

[0127] Considering formability, the viscosity of component (a) is preferably 1,000 mm. 2 / s to 50,000mm 2 / s, more preferably 1,000 mm 2 / s to 20,000mm 2 / s, but 3,000mm is still preferred. 2 / s to 8,000mm 2 / s. When the viscosity is 1,000 mm 2 At speeds above 50,000 mS, it becomes easier to adjust the required hardness of the elastic layer, and when the viscosity is 50,000 mm... 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.

[0128] Based on the liquid silicone rubber mixture used to form the elastic layer, the amount of component (a) added is preferably 50% by volume or more for durability, preferably 85% by volume or less for heat transfer, and more preferably 60% by volume or more for durability, and more preferably 80% by volume or less for heat transfer.

[0129] Component (b): Organopolysiloxane containing silicon-bonded active hydrogen

[0130] Organopolysiloxanes containing silicon-bonded active hydrogen are used as crosslinking agents, which react with the unsaturated aliphatic groups of component (a) under the action of a catalyst to form cured silicone rubber.

[0131] 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 components having an average of more than three hydrogen atoms bonded to silicon atoms per molecule are preferred.

[0132] Specific examples of component (b) include linear organopolysiloxanes represented by formula (3) and cyclic organopolysiloxanes represented by formula (4).

[0133]

[0134] 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 unsubstituted or substituted hydrocarbon group with a monovalent valence that does not have an unsaturated aliphatic group.

[0135]

[0136] In equation (4), m 3 n is an integer greater than or equal to 0 (preferably 10 to 30). 4 It is an integer greater than or equal to 3 (preferably 5 to 20), and R 6 Each is an unsubstituted or substituted hydrocarbon group with a monovalent valence that does not have an unsaturated aliphatic group.

[0137] 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 Those same groups. Preferably, R 5 and R 6 Each of them is more than 50% methyl, and more 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.

[0138] Component (c): Catalyst

[0139] 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.

[0140] Component (d): Filler

[0141] As described above, the elastic layer contains filler.

[0142] The filler material is selected based on its thermal conductivity, specific heat capacity, density, particle size, and dielectric constant. Examples of fillers used to improve the heat transfer properties of inorganic materials (especially metals and metal compounds) include: 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.

[0143] Furthermore, considering the thermal conductivity, resistivity, and dielectric constant of the filler itself, fillers A and B are more preferably at least one filler selected from the group consisting of alumina, zinc oxide, metallic silicon, silicon carbide, boron nitride, and magnesium oxide.

[0144] Packing material A preferably comprises boron nitride. In particular, packing material A preferably comprises boron nitride in a plate shape.

[0145] The filler A has a particle size (D10) of 10% based on the volume distribution that is preferably 10.0 to 40.0 μm and more preferably 10.0 to 17.0 μm.

[0146] The filler A has a particle size (D50) of 50% of the volume distribution that is preferably 10.0 to 40.0 μm, and more preferably 11.0 to 20.0 μm.

[0147] The filler A has a 90% particle size (D90) based on the volume distribution that is preferably 10.0 to 40.0 μm and more preferably 16.0 to 24.0 μm.

[0148] Filler B may contain, for example, alumina particles.

[0149] The filler B has a particle size (D10) of 10% based on volume distribution that is preferably 3.0 μm or more and less than 10.0 μm, and more preferably 3.0 to 5.0 μm.

[0150] The filler B has a particle size (D50) of 50% based on volume distribution that is preferably 3.0 μm or more and less than 10.0 μm, and more preferably 3.0 to 6.0 μm.

[0151] The filler B has a 90% particle size (D90) based on the volume distribution that is preferably 3.0 μm or more and less than 10.0 μm, and more preferably 5.0 to 9.9 μm.

[0152] In the following description, 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. Corona charging methods include the scorotron method, in which a gate electrode is provided between the corona wire and the component to be charged, and the corotron method, in which no gate electrode is provided. Considering the controllability of the surface potential of the component to be charged, the scorotron method is preferred.

[0153] like Figure 4A and Figure 4B As shown, the corona charging device 2 includes a front block 201, a rear block 202, and shields 203 and 204. Furthermore, a discharge wire 205 is tensioned between the front block 201 and the rear block 202, and discharges when a charging bias is applied from a high-voltage power supply, charging the surface of the uncured elastic layer 41c on the substrate, which is the component to be charged.

[0154] Similar to the construction 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 charge 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 surface of the elastic layer 41c.

[0155] To describe in detail the manufacturing method of the fixing component according to the above embodiment, firstly, an elastic layer containing silicone rubber including 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 the width direction. Then, a voltage is 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 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. Then, the elastic layer is cured by heating or the like, fixing the orientation of the filler.

[0156] The absolute value of the voltage applied to the grid 206 is preferably in the range of 0.1 kV to 3 kV (0.2 to 6 kV at Vp-p in the case of AC application) 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 to generate an electric field in the thickness direction of the elastic layer 41c. If the sign of the applied voltage is the same as the sign of the voltage applied to the line, the effect obtained is the same even if the direction of the electric field is opposite (whether negative or positive).

[0157] Furthermore, when AC charging is performed to suppress the liquid surface flow described later, it is desirable that the waveforms of the lines and the grid be in phase. 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 constant 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.

[0158] 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 flow, and the surface properties of the elastic layer 41c may deteriorate. Therefore, the absolute value of the voltage applied to the grid 206 is more preferably in the range of 0.1 kV to 1.5 kV (0.2 kV to 3 kV at Vp-p in the case of AC application). This liquid flow can be mitigated by AC charging.

[0159] As a construction for controlling the potential on the surface of the elastic layer in the longitudinal direction, for example, one could use... Figure 4A The structure shown illustrates that, when a voltage is applied to the grid 206, the entire elastic layer 41c can be charged by rotating the fixing member 41 around its central axis. Here, it is preferable to set the rotation speed of the fixing member to 10 rpm to 500 rpm and the processing time to 20 seconds or more to stably orient the filler. As described above, by controlling 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 .

[0160] The discharge wire 205 can be made of stainless steel, nickel, molybdenum, or tungsten, but tungsten is preferred as it is an extremely stable metal. Here, the discharge wire tensioned inside the shield can have a circular cross-sectional shape or a serrated shape.

[0161] 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, either DC 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 rectangular wave or a sine wave, etc.

[0162] <Surface Layer>

[0163] 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 less than 100 μm, preferably 10 to 70 μm. For example, the fluoropolymer layer may contain, for example, PTFE, FEP, and PFA, and PFA is preferred considering mold release and rigidity. PFA is a copolymer of perfluoroalkyl vinyl ether (PAVE) and tetrafluoroethylene (TFE).

[0164] Examples of methods for forming a surface layer 41a containing PFA include applying a dispersion (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.

[0165] 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 451HP-J (product name, available from Chemours-Mitsui Fluoroproducts Co., Ltd.) with small spherulite size.

[0166] Pre-treating the inner surface of surface layer 41a with sodium, excimer laser, ammonia, or plasma etching improves adhesion. In this example, a 20 μm thick PFA tube obtained by extrusion molding is used.

[0167] <Adhesive Layer>

[0168] The surface layer 41a can be bonded to the surface of the elastic layer 41c via an adhesive layer (not shown) therebetween. When an adhesive layer is provided, it is easier to bond the elastic layer and the surface layer. 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. The adhesive can be a solution-based adhesive or a hot-melt adhesive.

[0169] There are no particular restrictions on the adhesive; any known adhesive may be used, but silicone rubber adhesives are preferred.

[0170] The thickness of the adhesive layer is not particularly limited, but is preferably 1 to 20 μm, more preferably 3 to 10 μm.

[0171] Electrophotographic image forming equipment

[0172] 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 a cross-sectional view of the recording material in the transport direction. In this embodiment, the color electrophotographic printer is simply referred to as a "printer".

[0173] Figure 1 The 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 squeegee 17. After the transfer, toner residue on the photosensitive drum 11 is removed by a cleaner 15. Thus, the surface of the photosensitive drum 11 is cleaned and ready for the next image forming.

[0174] On the other hand, the recording material P is fed one after another from the paper feed cassette 20 or the multiple paper feed tray 25 to a pair of positioning rollers 23 in the direction of arrow 3. The pair of positioning rollers 23 first receive the recording material P and straighten it if it is tilted. Then, the pair of positioning rollers 23, synchronized with the toner image on the intermediate transfer belt 31, transfer 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 a transfer member (e.g., the secondary transfer roller 35). Then, when the recording material P is heated and pressurized by the fixing device 40, the toner image on the recording material P is fixed to the recording material.

[0175] 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 thin-film heating type (tensionless type) heating device. In this example, this type of heating device is used, but roller-type or thin-film type heating devices can also be used.

[0176] Reference numeral 43 indicates a ceramic heater (hereinafter referred to as the heater) as a heating element. The heater 43 has the following basic structure: it includes an elongated thin ceramic substrate with its longitudinal direction perpendicular to the drawing plane and a heating resistance layer disposed on the surface of the substrate for applying current. The heater 43 is a low heat capacity heater, and when current is applied to the heating resistance layer, it heats its entire surface with a rapidly increasing characteristic. Furthermore, the heater is configured to switch the area where current is applied according to the longitudinal width dimension of the recording material.

[0177] 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 3 The 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.

[0178] The pressure roller 44 is a heat-resistant elastic pressure roller serving as a pressure member, and has a core and an elastic layer made of heat-resistant rubber such as silicone rubber or 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 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 including a surface layer 41a, an elastic layer 41c, and a substrate 41b.

[0179] 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 are pressed against each other by the fixing film 41 therebetween, overcoming the elasticity of the elastic layer, and a fixing roller gap N with a predetermined width can be formed as a heating part.

[0180] The pressure roller 44 is driven by a driving means (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 the rotational force is applied to the cylindrical fixing film 41 due to the pressing 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 downward 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.

[0181] The pressure roller 44 is driven to rotate, and the cylindrical fixing film 41 rotates accordingly, applying current to the heater 43 and causing the heater to heat up rapidly to a predetermined temperature, entering a temperature-regulating state. In this state, 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-bearing side of the recording material P is in 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. The recording material P passing through the fixing roller gap N separates from the surface curvature of the fixing film 41 and is discharged from the conveyor.

[0182] 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. Increasing the surface pressure in the fuser roller gap can increase the amount of toner deformation and improve image quality.

[0183] The pressure applied to the fixing roller gap N is measured using a tactile sensor (commercially available from Nitta Corporation). 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 in the transport direction of the recording material in the fixing roller gap N is the maximum value of the pressure distribution in the paper passage area of ​​the roller gap N, passing through center A in the transport direction. Here, center A is the center of the paper passage area of ​​the roller gap N in the longitudinal direction. The paper passage area of ​​the roller gap N is the area through which the recording material fixed by the fixing device 40 can pass.

[0184] Reference numeral 45 indicates a contact thermometer (thermostat) 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, and is a component that holds the heater 43 heated to a high temperature.

[0185] The method for measuring the physical properties in this disclosure is described below.

[0186] <Measurement of thermal conductivity of the elastic layer in the thickness direction>

[0187] The thermal conductivity λ of the elastic layer in the thickness direction is calculated by the following formula.

[0188] λ=α×C p ×ρ

[0189] In this 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 at constant pressure C are... p The values ​​of and density ρ are determined by the following method.

[0190] Thermal diffusivity α

[0191] The thermal diffusivity α of the elastic layer in the thickness direction was measured at room temperature (25°C) using a periodic heating thermal performance measurement device (product name: FTC-1, commercially 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, flat measuring head (tip) φ4 mm, commercially 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 using a 1kg weight.

[0192] Specific heat at constant pressure C p

[0193] The isobaric specific heat of the elastic layer was measured using a differential scanning calorimeter (product name: Q2000, available from TA Instruments).

[0194] Specifically, aluminum discs are used as sample and reference discs. First, for blank measurements, a procedure is performed with both discs empty, the temperature is kept constant at 15°C for 10 minutes, then increased to 215°C at a rate of 10°C / min, and the temperature is kept constant at 215°C for an additional 10 minutes.

[0195] Next, 10 mg of synthetic sapphire with a known isobaric specific heat 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 tray, and measured using the same procedure. These measurements were analyzed using the specific heat analysis software accompanying the differential scanning calorimeter, and the isobaric specific heat C at 25 °C was calculated based on the average of five measurements. p .

[0196] Density ρ

[0197] The density of the elastic layer was measured using a dry automatic densitometer (product name: AccuPyc II1340, available from Shimadzu Corporation).

[0198] Specifically, using 10cm 3 A 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 located 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 mass of the sample piece and the measured volume, and an average value is obtained.

[0199] The thermal conductivity λ of the elastic layer in the thickness direction is converted from the isobaric specific heat C of the elastic layer. p (J / (kg·K)), density ρ(kg / m³) 3 ), and the measured thermal diffusivity α (m 2 Calculated by / s.

[0200] Measurement of filler content

[0201] 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, commercially available 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.

[0202] <Content V A Content V B Calculation of average aspect ratio >

[0203] First, the filler collected during the filler content measurement was dispersed in toluene to prepare a dispersion. The dispersion 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 was adjusted so that the filler particles did not overlap and could be observed individually. Next, the sample was placed on a 45° inclined stage, and the filler was observed using an FE-SEM (product name: SU8220, commercially available from Hitachi High-Tech Corporation) under the following conditions.

[0204] (SEM observation conditions)

[0205] Accelerating voltage: 2.0kV

[0206] WD: 12mm

[0207] Sample tilt angle: 45°, -45°

[0208] Adjust the magnification appropriately according to the size of the packing material.

[0209] By observing under the above conditions, the upper and side surfaces of the sample can be observed. Observational images of each individual filler visible on both the entire upper and side surfaces are obtained. The major axis d1 and minor axis d2 are determined from the upper surface observation image, and the thickness h is determined from the side surface observation image.

[0210] (Calculation method for major axis d1 and minor axis d2)

[0211] 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 approximated as an ellipse, and its major axis d1 and minor axis d2 were determined. Specifically, the user first selected Analyze-Set Scale in ImageJ software and used the scale bar of the SEM observation condition display cell to set the actual length of each pixel.

[0212] Next, the user selects Image-Adjust-Threshold and specifies a brightness threshold to select only the filler portion. Then, the user selects Analyze-Set Measurements, checks Fit ellipse, selects Analyze-Analyze Particles, and sets the output Major value to the major axis d1 of the filler and the Minor value to the minor axis d2 of the filler.

[0213] (Method for calculating thickness h)

[0214] For observation images of the side surface of the filler, the height of the filler from the substrate surface of the sample being observed is defined as the thickness h.

[0215] 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.

[0216] Volume V f =3.14×d1 / 2×d2 / 2×h

[0217] Particle size R f =(V f ×6 / 3.14) 1 / 3

[0218] Determine the V of each of the 100 packing materials. f R f And aspect ratio, the particle size R f Fillers with a particle size of 10 to 40 μm are defined as filler A, and particle size R is defined as filler A. f Packing material with a diameter greater than 3 μm and less than 10 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 The volume V of all packing materials f The sum of V, and V is calculated by the following formula. A and V B .

[0219] V A =(filler content (volume %)) × (total volume of filler A, V) f ) / V

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

[0221] 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, based on the volume V of 100 packings... f By changing 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 V is used to calculate the value V. A+B .

[0222] (average orientation angle θ of the packing) Ave (Calculation)

[0223] 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.

[0224] (Preparation of the cross-section for measurement)

[0225] 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 plane that rotates from the first plane to the thickness direction-axial direction of the fixing member 1 in increments of 10° is defined as the second to tenth planes.

[0226] like Figure 6 As shown, the fixing member 41 is cut into circular slices with a width of 500 μm or more in the axial direction, with the slices passing through the midpoint of the fixing member 41. Then, it is cut in the axial direction to obtain a strip sample. The strip sample is then 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. These cross-sections are defined as the first to tenth cross-sections.

[0227] 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. When using an ion beam cross-section forming method, it is possible to prevent filler shedding and contamination from excess components (such as polishing agents) that tend to occur during the cross-section polishing process, and a cross-section with fewer polishing marks can be formed. A cross-section polishing machine (IM4000+, commercially available from Hitachi High-Tech Corporation) is used for the ion beam cross-section forming process.

[0228] (Observation and binarization of cross-sectional images)

[0229] 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 of the entire area covering the elastic layer in the thickness direction × a 500 μm area in the direction perpendicular to the thickness was obtained. In this case, the midpoint at 500 μm in the direction perpendicular to the thickness coincides with the midpoint of the fixing member in the axial direction.

[0230] 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 Analyze-SetScale in ImageJ and set the actual length of each pixel using the image scale bar. The user 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 that showed as much of the elastic layer as possible.

[0231] (θ Ave (Calculation)

[0232] Each filler in the 10 obtained cross-sectional binarized images is approximated as an ellipse, and image analysis software is used to calculate the major axis a, the minor axis b, and the angle θ formed by the major axis of the ellipse relative to the thickness direction of the elastic layer (called the filler orientation angle). Specifically, after obtaining the binarized image in ImageJ as described above, the user selects Analyze-SetMeasurements, checks Fit ellipse, selects Analyze-Analyze Particles, and sets the output Major value to the major axis a of the filler, the Minor value to the minor axis b, and the Angle value to θ.

[0233] 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°. This value is then converted so that θ ranges from 0 to 90°. Therefore, when the packing orientation angle is closer to 0°, the packing is more strongly oriented in the thickness direction.

[0234] 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 is calculated, and data is extracted only for fillers where the value of major axis length a / minor axis length b is 3.0 or higher. The average orientation angle θ of all fillers with a major axis length / minor axis length of 3.0 or higher extracted from the 10 cross-sectional images is defined as the average orientation angle θ of the filler relative to the thickness direction of the elastic layer. Ave .

[0235] <Measurement of the thickness of the elastic layer>

[0236] The average orientation angle θ of the filler is calculated. 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.

[0237] <Measurement of the elastic modulus of the elastic layer>

[0238] The tensile modulus of elasticity is measured by the following method and used as the modulus of elasticity of the elastic layer.

[0239] Sample pieces were cut from the elastic layer using a stamping die (such as dumbbell type No. 8 as specified in JIS K 6251:2004), and the thickness near the center of the measurement point was measured. Next, the cut sample pieces were tested at room temperature using a precision universal testing machine (product name: Autograph AG-X, commercially available from Shimadzu Corporation) at a tensile speed of 200 mm / min. A graph was created based on the measurement results, where the horizontal axis represents the strain of the sample piece and the vertical axis represents the tensile stress. The tensile modulus was defined as the slope obtained by a linear approximation of the measured data within the strain range of 0 to 10%. The arithmetic mean of 10 sample pieces was used.

[0240] Example

[0241] The present disclosure will now be described in more detail with reference to embodiments and comparative examples, but the aspects of the present disclosure are not limited thereto.

[0242] (Grading treatment of packing material)

[0243] Using spherical alumina particles (trade names: Alunabeads CB-P05, CB-P10, and CB-P15, manufactured by Resonac Corporation) and flat boron nitride particles (trade names: SGP and XGP, manufactured by Denka Co., Ltd.) as raw materials, fillers 1 to 16 with desired particle size distributions are obtained by classifying the fillers.

[0244] The classification process was performed using an inertial classification type curved jet (commercially available from Nittetsu Mining Co., Ltd.) with a feed rate of 5 kg / hr. The F classification edge (fine particle classification edge) and G classification edge (coarse particle classification edge) were adjusted to obtain the desired particle size distribution.

[0245] For the obtained packings 1 to 16, to be compatible with V A V B Using the same method as calculating the average aspect ratio, determine the V of 100 packings. f and Rf 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 for fillers 1 to 16 and their D50, D10, and D90 values.

[0246] <Example 1>

[0247] In this embodiment, preparation as follows Figure 3 The fixing film shown.

[0248] (Substrate)

[0249] SUS with an inner diameter of 24 mm and a thickness of 30 μm is used as the substrate. Specifically, an SUS toroidal strip 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 core is inserted into the toroidal strip for processing during a series of manufacturing steps.

[0250] (Formation of the internal sliding layer)

[0251] 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.

[0252] (Preparation of silicone rubber mixture)

[0253] Liquid addition-curing silicone rubber mixtures are prepared by mixing the following components (a) to (d) using the following procedure.

[0254] Component (a): A linear organopolysiloxane with unsaturated aliphatic groups

[0255] Component (b): Organopolysiloxane containing silicon-bonded active hydrogen

[0256] Component (c): Catalyst

[0257] Component (d): Filler

[0258] First, as component (a), 100 parts by weight of an organosilicon polymer are prepared, wherein the organosilicon polymer has vinyl groups as unsaturated aliphatic groups only at both ends of the molecular chain, and methyl groups as unsubstituted hydrocarbon groups that do not contain other unsaturated aliphatic groups. This organosilicon polymer (product name: DMS-V35, commercially available from Gelest, viscosity 5,000 mm) 2 / s) will be referred to as "Vi" in the following text.

[0259] Next, 87.1 parts by weight of packing 1 and 50.7 parts by weight of packing 14 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 and mixed at 600 rpm for 2 minutes to obtain mixture 1.

[0260] Next, 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 delay agent in an equal weight of toluene is added to mixture 1 to obtain mixture 2.

[0261] Next, 0.1 parts by mass of a hydrosilylation catalyst (a platinum catalyst: a mixture of 1,3-divinyltetramethyldisiloxane platinum complex, 1,3-divinyltetramethyldisiloxane, and 2-propanol) is added as component (c) to mixture 2 to obtain mixture 3.

[0262] In addition, 1.3 parts by weight of an organosilicon polymer having a straight-chain siloxane backbone and active hydrogen groups bonded only on the side chains (product name: HMS-301, commercially available from Gelest, viscosity 30 mm) was weighed out. 2 / s, referred to below as "SiH") as component (b). It is added to mixture 3 and mixed thoroughly to obtain a liquid addition-curing silicone rubber mixture.

[0263] (Formation of the primer layer and elastic layer)

[0264] The following procedure is used to form a primer layer and an elastic layer on a substrate on which an internal sliding layer has been formed.

[0265] Hydrogenated silyl-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 then the substrate was calcined in an electric furnace set to 160°C for 30 minutes.

[0266] A silicone rubber compound is applied to a primer-treated substrate in a 250 μm thickness using a ring coating method. This is called an uncured ring band.

[0267] Next, a corona charging device with a charging area width of 295 mm was positioned facing each other along 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-p: 3,000 V), frequency: 0.025 Hz, charging time: 160 seconds, and distance between the grid electrode and the strip: 3 mm.

[0268] 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.

[0269] (Coating of the adhesive layer)

[0270] Apply an addition-curing silicone rubber adhesive (product name: SE1819CV A / B; available from Dow Corning Toray Co., Ltd.) almost uniformly to the surface of the cured elastic layer of the annular strip until the thickness is about 10 μm as an adhesive layer.

[0271] (Formation of the surface layer)

[0272] After applying the adhesive, PFA (product name: AP-231SH; commercially available from Daikin Industries, Ltd.) is extruded and shaped 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 applied to the fluoropolymer tube by a vacuum expansion and coating method (vacuum expansion coating). Then, the surface of the strip is 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.

[0273] The annular strip is heated in an electric furnace set at 200°C for 1 hour to cure the adhesive, thus fixing the fluoropolymer tube to the elastic layer.

[0274] The two ends of the obtained annular strip are cut to obtain a fixing film with a width of 336.5 mm.

[0275] The thermal conductivity λ of the elastic layer in the thickness direction and the filler content V of the prepared fixing film were determined. A V B The average aspect ratio of packings A and B, θ 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.

[0276] <Durability>

[0277] Based on the following evaluations, use Figure 2 The durability of the thin-film heating type fixing device 40, which introduces the prepared fixing film, is evaluated.

[0278] First, the size of the contact area between the fixing film and the pressure roller is 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 of the fixing roller gap N in the conveying direction is set so that the maximum surface pressure of the recording material in the fixing roller gap N in the conveying direction is 0.35 MPa.

[0279] Then, the evaluation is conducted under the following conditions.

[0280] Test environment: 23℃ room temperature, 50% relative humidity

[0281] Processing speed: 200mm / second

[0282] Printing speed: 30 pages / minute

[0283] Surface temperature of the paper passage portion of the fixing film: 170℃

[0284] Paper feeding conditions: Continuous paper feeding (A4 size, landscape orientation, GF-C068)

[0285] If the evaluation result based on the following evaluation criteria is A to C, then the effect of this disclosure has been achieved.

[0286] (Evaluation Criteria)

[0287] A: Even after more than 400,000 sheets of paper, the elastic layer did not break.

[0288] B: Even after more than 300,000 but less than 400,000 sheets of paper, the elastic layer did not break.

[0289] C: Even after more than 250,000 but less than 300,000 sheets of paper, the elastic layer did not break.

[0290] D: The elastic layer breaks after fewer than 250,000 sheets of paper.

[0291] <Examples 2 to 17 and Comparative Examples 1 to 11>

[0292] Except for changing the type of filler used, the amount of filler added, and the voltage applied to the grid to those shown in Table 2, the fixing films of Examples 2 to 17 and Comparative Examples 1 to 11 were obtained in the same manner as in Example 1.

[0293] In Comparative Example 9, the fixing film was obtained in the same manner as in Example 2, except that no alternating electric field was applied to the surface of the elastic layer of the uncured annular strip before curing.

[0294] In Examples 2 to 17 and Comparative Examples 1 to 11, the thermal conductivity λ of the elastic layer of the prepared fixing film in the thickness direction and the filler content V were determined. A V B The average aspect ratio of packings A and B, θ 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.

[0295] [Table 1]

[0296]

[0297] [Table 2]

[0298]

[0299] 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 content of filler in the elastic layer (vol.%), where vol.% represents volume%. 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."

[0300] 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 in 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.

[0301] 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 15% to 50% by volume. In the packing material, packing material with a particle size of 10 to 40 μm is defined as packing material A, and Fillers with a particle size of 3 μm or larger but less than 10 μm 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 between 5.0 and 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 toward the plane of the elastic layer in the thickness-axial direction in increments of 10° 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 acquired as first to tenth cross-sectional images, such that each image is parallel to the first to tenth planes, and its center in the direction perpendicular to the thickness direction of the elastic layer coincides with 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 tenth binarized images, when the shape of the filler is approximated as an ellipse, The filler, which is approximately elliptical and has a major axis length / minor axis length ratio of 3.0 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 10.0 to 40.

0.

5. The electrophotographic component according to claim 1 or 2, The filler content in the elastic layer is 20% to 40% by volume. The content V A It is 10 to 20% by volume, and The content V B For a volume of 10 to 20%.

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 to 2.00 MPa.

9. The electrophotographic component according to claim 1 or 2, wherein the thickness of the elastic layer is 150 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; as well as A pressure member faces the fixing member and forms a fixing roller gap between the pressure member and the fixing member. Recording material carrying the toner image is held and conveyed 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 10.

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 to 0.40 MPa.

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

Images