Electrophotographic fixing member, fixing device, and electrophotographic image forming apparatus

Abstract

To provide a fixing member that prevents the occurrence of destruction and plastic deformation even after long-term use despite the inclusion of an elastic layer containing metal silicon powder having a high aspect ratio.SOLUTION: A fixing member has a substrate, and an elastic layer on the substrate. The elastic layer contains silicone rubber, and metal silicon powder dispersed in the silicone rubber. The elastic layer has a modulus of elasticity of 0.10 MPa or more and 0.40 MPa or less. The metal silicon powder has an aspect ratio of 1.4 or more and 2.5 or less and an angle of repose of 35 degrees or more and 52 degrees or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to an electrophotographic fixing member and fixing device used in an electrophotographic image forming apparatus, and also to an addition-curable liquid silicone rubber mixture. [Background technology]

[0002] In a heat fixing device used in an electrophotographic image forming apparatus such as a copier or printer, two rotating bodies, such as a pair of heated rollers, a film and a roller, a belt and a roller, or a belt and a belt, are pressed together. These rotating bodies are called fixing members. A recording material carrying an image formed with unfixed toner is introduced into the pressure contact area (fixing nip) formed between these rotating bodies. The unfixed toner is then heated along with the recording material. The heated toner is softened and melted and pressed against the recording material, thereby fixing the image to the recording material. The rotating body that comes into direct contact with the toner held on the recording material functions as a heating member, and its form may be, for example, a roller, a film, or a belt. The rotating body that forms the fixing nip together with the heating member functions as a pressure member, and its form may be, like the heating member, a roller, a film, or a belt. Among these fixing members, the fixing member that comes into direct contact with the toner held on the recording material and heats the toner, i.e., the heating member, is required to be able to supply heat to the recording material and the toner in the fixing nip to soften and melt the toner. Therefore, it has been proposed to incorporate metal silicon powder into the elastic layer of the fixing member used as a heating member in order to increase its thermal conductivity (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-171946 Summary of the Invention [Problem to be solved by the invention]

[0004] In some cases, the heating element is required to have a reduced thermal capacity in order to further shorten the first print out time (FPOT). Metal silicon powder is effective not only for improving the thermal conductivity of the elastic layer but also for reducing the thermal capacity of the elastic layer. The inventors investigated the use of metal silicon powder with a high aspect ratio in order to further improve the thermal conductivity of the elastic layer using metal silicon powder. Specifically, they investigated the inclusion of metal silicon powder with an aspect ratio of 1.4 to 2.5 in the elastic layer. This was based on the consideration that, compared with spherical metal silicon powder, metal silicon powder with a high aspect ratio is more likely to form heat flow paths in the elastic layer due to contact between the metal silicon powder particles. As a result of this investigation, it was confirmed that an elastic layer containing metal silicon powder with an aspect ratio of 1.4 to 2.5 has improved thermal conductivity. However, a new problem was discovered in that elastic layers containing such high-aspect-ratio metal silicon powders suffer from fracture and plastic deformation when repeatedly compressed at high temperatures, for example, above 200° C. This problem was particularly pronounced in flexible elastic layers with an elastic modulus of 0.4 MPa or less. Therefore, we recognized that in order to achieve an even lower hardness of the elastic layer while increasing the thermal conductivity and reducing the heat capacity of the elastic layer by incorporating metal silicon powder, it was necessary to develop new technology to prevent the occurrence of fracture and plastic deformation of the elastic layer due to the use of metal silicon powder with a high aspect ratio.

[0005] One aspect of the present disclosure is directed to providing a fixing member that is resistant to fracture and plastic deformation even with long-term use, despite having an elastic layer containing metal silicon powder with a high aspect ratio. Another aspect of the present disclosure is directed to providing a fixing device and an electrophotographic image forming apparatus that can stably form high-quality electrophotographic images. Yet another aspect of the present disclosure is directed to providing an addition-curable liquid silicone rubber mixture that contains metal silicon powder with a high aspect ratio and produces a silicone rubber cured product that is resistant to fracture and plastic deformation even with repeated compression. [Means for solving the problem]

[0006] According to one aspect of the present disclosure, there is provided a fixing member having a substrate and an elastic layer on the substrate, wherein the elastic layer contains silicone rubber and metal silicon powder dispersed in the silicone rubber, the elastic layer having an elastic modulus of 0.10 MPa or more and 0.40 MPa or less, and the metal silicon powder having an aspect ratio of 1.4 or more and 2.5 or less and an angle of repose of 35 degrees or more and 52 degrees or less.

[0007] According to another aspect of the present disclosure, there is provided a fixing device including the fixing member, and an electrophotographic image forming apparatus including the fixing device. [Effects of the Invention]

[0009] According to one aspect of the present disclosure, a fixing member can be obtained that is resistant to fracture and plastic deformation even with long-term use, despite having an elastic layer containing metal silicon powder with a high aspect ratio. Also, according to one aspect of the present disclosure, a fixing device and an electrophotographic image forming apparatus that can stably form high-quality electrophotographic images can be obtained. 。 [Brief explanation of the drawings]

[0010] [Figure 1]1A and 1B are cross-sectional views of a fixing member according to the present disclosure, in which (a) has an endless belt shape and (b) has a roller shape. [Figure 2] FIG. 2 is an explanatory diagram of an example of a step of laminating a fluororesin surface layer. [Figure 3] 1 is a cross-sectional view illustrating an example of a fixing device including a fixing member according to the present disclosure. [Figure 4] FIG. 1 is a perspective view of a jig for evaluating the pressure resistance durability of an elastic layer according to the present disclosure. [Figure 5] SEM images of metal silicon powder. (a) SEM image before chamfering, (b) SEM image after chamfering. DETAILED DESCRIPTION OF THE INVENTION

[0011] It is not clear why an elastic layer containing metal silicon powder with a high aspect ratio may break or undergo plastic deformation when repeatedly compressed at high temperatures, for example, above 200°C. However, it is thought that this is because metal silicon powder with a high aspect ratio has sharp corners, and when the elastic layer is repeatedly compressed, stress is concentrated at the corners of the metal silicon powder. Based on these considerations, the inventors incorporated metal silicon powder that had been treated to round off sharp edges (hereinafter referred to as "corner rounding") while maintaining a high aspect ratio into an elastic layer, and found that this effectively prevented the elastic layer from breaking or plastically deforming even when repeatedly compressed at high temperatures.

[0012] The degree of chamfering of the metallic silicon powder correlates with the angle of repose of the metallic silicon powder. Specifically, metallic silicon powder that has been chamfered is less likely to pile up into a mountain-like accumulation of powder, and tends to have a smaller angle of repose. The angle of repose can be measured in accordance with the method specified in "Alumina Powder - Part 2: Measurement of Physical Properties - 2: Angle of Repose" in Japanese Industrial Standards (JIS) R9301-2-2:1999.

[0013] Furthermore, in an elastic layer containing metal silicon powder having an aspect ratio of 1.4 or more and 2.5 or less and an angle of repose of 35 degrees or more and 52 degrees or less, even if the elastic modulus of the elastic layer is 0.4 MPa or less, it is possible to prevent fracture and plastic deformation due to repeated compression at high temperatures.

[0014] The present disclosure will be described in detail below. <Fixing material> The configuration of a fixing member according to one embodiment of the present disclosure will be described with reference to the drawings. 1(a) and 1(b) are cross-sectional views of a fixing member according to one embodiment of the present disclosure. FIG. 1(a) shows an example of a fixing member having an endless belt shape (hereinafter also referred to as a "fixing belt"), and FIG. 1(b) shows an example of a fixing member having a roller shape (hereinafter also referred to as a "fixing roller"). In FIGS. 1(a) and 1(b), reference numeral 1 denotes a substrate, and reference numeral 2 denotes a silicone rubber-containing elastic layer covering the outer peripheral surface of the substrate 1. Thus, the fixing member according to the present disclosure includes the substrate 1 and the silicone rubber-containing elastic layer 2 on the substrate 1. As shown in these figures, the fixing member may include a surface layer 4 on the silicone rubber-containing elastic layer 2. An adhesive layer 3 may also be provided between the silicone rubber-containing elastic layer 2 and the surface layer 4. In this case, the surface layer 4 is fixed to the outer peripheral surface of the silicone rubber-containing elastic layer 2 by the adhesive layer 3.

[0015] [Base] When the fixing member is a fixing belt as shown in FIG. 1(a), the substrate can be made of a metal such as an electroformed nickel sleeve or a stainless steel sleeve, or a heat-resistant resin such as polyimide. A layer for improving adhesion to the elastic layer can be provided on the outer surface of the substrate (the surface on the silicone rubber-containing elastic layer side). That is, the silicone rubber-containing elastic layer only needs to be provided on the outer peripheral surface of the substrate, and other layers may be provided between the silicone rubber-containing elastic layer and the substrate. Furthermore, a layer for imparting functions such as abrasion resistance and lubricity can be further provided on the inner surface of the substrate (the surface opposite the outer surface).

[0016] When the fixing member is a fixing roller as shown in Fig. 1(b), the base can be made of a metal core such as aluminum or iron or an alloy, and it is sufficient if it has the strength to withstand the heat and pressure applied in the fixing device. In Fig. 1(b), a solid metal core is used as the base, but the base may also be made of a hollow metal core, and may have a heat source such as a halogen lamp inside.

[0017] [Elastic layer] The fixing member according to the present disclosure can be used as either or both of a heating member and a pressure member in a fixing device. When used as a heating member, the elastic layer functions as a layer that allows the outer surface of the heating member to conform to the irregularities of the paper during fixing. When used as a pressure member, the elastic layer functions as a layer that ensures a sufficient width for the fixing nip formed between the heating member and the pressure member. To achieve these functions in an environment where the non-paper passing area reaches a high temperature of approximately 240°C, the elastic layer contains a silicone rubber with excellent heat resistance as a binder. That is, the elastic layer contains silicone rubber and metal silicon powder dispersed in the silicone rubber. The elastic layer can be formed, for example, by curing an addition-curable liquid silicone rubber mixture containing metal silicon powder and addition-curable liquid silicone rubber. That is, the elastic layer can be a cured product of the addition-curable liquid silicone rubber mixture, and can contain a cured product of the addition-curable liquid silicone rubber and metal silicon powder present in the cured product. The metallic silicon powder and silicone rubber that are components of the elastic layer will be described in detail below.

[0018] (metallic silicon powder) The metal silicon powder has an aspect ratio of 1.4 or more and 2.5 or less, and an angle of repose of 35 degrees or more and 52 degrees or less. In the present disclosure, the aspect ratio of a metal silicon powder is the ratio of the long diameter to the short diameter of a particle (long diameter / short diameter). The particle size and shape of each metal silicon powder particle are different and have a distribution. Therefore, for example, the aspect ratio is determined by measuring the long diameter and short diameter of each particle for 100 or more powder particles observed with a scanning electron microscope (SEM), calculating the long diameter / short diameter ratio, and then arithmetically averaging the measured values. Metallic silicon powder can be produced, for example, by reducing silica, pulverizing, and classifying it. Metallic silicon powder has a heat capacity per unit volume of approximately 1.7 MJ / m. 3 ·K, and the heat capacity per unit volume of alumina, which is widely used to improve the thermal properties of silicone rubber-containing elastic layers, is approximately 3.0 MJ / m 3 ·K. The thermal conductivity of metallic silicon is high, at around 150 W / m·K. Metallic silicon powders with an aspect ratio of 1.4 or more and 2.5 or less are commercially available, for example, as "Metallic Silicon #350," "Metallic Silicon #600," "Metallic Silicon #350WB," and "Metallic Silicon #600WB" (all trade names, manufactured by Kinsei Matec Co., Ltd.).

[0019] In this disclosure, metal silicon powder with an aspect ratio of 1.4 or more and 2.5 or less is subjected to a chamfering process to adjust the angle of repose of the metal silicon powder to 35 degrees or more and 52 degrees or less while maintaining the aspect ratio. Mechanical and physical methods can be used to chamfer metal silicon powder. For example, a particle design / surface modification device (product name: Hybridization System, manufactured by Nara Machinery Works) is composed of a high-speed rotating rotor, stator, and circulation circuit. The metal silicon powder introduced into the device is dispersed within the device and repeatedly subjected to mechanical actions such as impact, compression, friction, and shear forces, resulting in chamfering, and then collected by a collector. In addition, a multipurpose powder processing device (product name: Faculty, manufactured by Hosokawa Micron Corporation) uses a hammer to rotate at high speed, and the metal silicon powder is removed from its outlet.

[0020] The degree of chamfering can be adjusted mainly by the rotation speed and processing time of the apparatus. Specifically, for example, the angle of repose can be adjusted to within the above range by processing for 3 to 30 minutes at a peripheral speed of 60 to 100 m / s. The atmosphere in which the chamfering process is performed is not particularly limited, but an inert gas atmosphere such as argon is preferred to suppress oxidation of the silicon metal. This is because it is believed that when silicon metal is oxidized, the thermal conductivity of the oxidized portion becomes lower than that of the non-oxidized portion. The angle of repose of the silicon metal powder can be measured, for example, using a commercially available powder measurement and powder property evaluation device (trade name: Powder Tester PT-X, manufactured by Hosokawa Micron Corporation).

[0021] The particle size of the metal silicon powder is not particularly limited, but is preferably in the range of 0.1 to 100 μm, and more preferably in the range of 1 to 50 μm. By setting the particle size within the above range, an increase in the elastic modulus of the elastic layer due to the inclusion of the metal silicon powder can be suppressed. Furthermore, a decrease in the surface properties of the elastic layer can be significantly suppressed. The particle size of the metal silicon powder can be determined, for example, using a laser diffraction / scattering particle size distribution analyzer.

[0022] The content of the metal silicon powder in the elastic layer is preferably 15% to 55% by volume, more preferably 30% to 50% by volume, relative to the elastic layer. By keeping the content within this range, it is possible to increase the thermal conductivity while suppressing an increase in the heat capacity of the elastic layer.

[0023] (silicone rubber) The addition-curable liquid silicone rubber contains at least (a) an organopolysiloxane having an unsaturated aliphatic group such as a vinyl group in the molecule, (b) an organopolysiloxane having active hydrogen bonded to a silicon atom, and (c) a hydrosilylation catalyst, and optionally (d) a cure retarder.

[0024] Component (a): an organopolysiloxane having an unsaturated aliphatic group in the molecule; Examples of organopolysiloxanes having an unsaturated aliphatic group such as a vinyl group in the molecule include organopolysiloxanes containing at least two unsaturated aliphatic groups bonded to silicon atoms in one molecule. Specific examples include organopolysiloxanes according to the following (i) and (ii):

[0025] (i) one or both of intermediate units selected from the group consisting of intermediate units represented by R1R1SiO and intermediate units represented by R1R2SiO, and R1R1R2SiO 1 / 2 and a molecular terminal represented by the following structural formula 1.

[0026] [ka]

[0027] (ii) one or both of intermediate units selected from the group consisting of intermediate units represented by R1R1SiO and intermediate units represented by R1R2SiO, and R1R1R1SiO 1 / 2 and a molecular terminal represented by the following structural formula 2.

[0028] [ka]

[0029] In Structural Formula 1 and Structural Formula 2, R1 each independently represents an unsubstituted hydrocarbon group that does not contain an unsaturated aliphatic group, R2 each independently represents an unsaturated aliphatic group, and m and n each independently represent an integer of 0 or greater.

[0030] In addition, examples of the unsubstituted hydrocarbon group not containing an unsaturated aliphatic group represented by R1 in Structural Formula 1 and Structural Formula 2 include alkyl groups such as methyl, ethyl, and propyl groups, and aryl groups such as phenyl groups. Among these, R1 is preferably a methyl group. Furthermore, in Structural Formula 1 and Structural Formula 2, examples of the unsaturated aliphatic group represented by R2 include alkenyl groups such as vinyl, allyl, and 3-butenyl groups. Among these, R2 is preferably a vinyl group.

[0031] In structural formula 1, linear organopolysiloxanes where n=0 have unsaturated aliphatic groups only at both ends, while linear organopolysiloxanes where n=1 or more have unsaturated aliphatic groups at both ends and in the side chain. Furthermore, linear organopolysiloxanes of structural formula 2 have unsaturated aliphatic groups only in the side chain. One type of component (a) may be used alone, or two or more types may be used in combination.

[0032] When component (a) is used in the elastic layer of the fixing member, the viscosity is set to 100 mm from the viewpoint of formability. 2 / s or more, 50000mm 2 / s or less is preferable.

[0033] Component (b): an organopolysiloxane having active hydrogen atoms bonded to silicon atoms; The crosslinking agent for component (a), an organopolysiloxane having active hydrogen atoms bonded to silicon atoms, is a crosslinking agent that forms a crosslinked structure through a hydrosilylation reaction with the unsaturated aliphatic groups in component (a) under the catalytic action of component (c), which will be described later.

[0034] Any organopolysiloxane having a Si-H bond can be used as component (b), and examples include the organopolysiloxanes (iii) to (iv) below. Note that component (b) may be used alone or in combination of two or more.

[0035] (iii) From the viewpoint of forming a crosslinked structure by reaction with an organopolysiloxane having an unsaturated aliphatic group in the molecule, an organopolysiloxane having an average of three or more hydrogen atoms bonded to silicon atoms per molecule. (iv) Organopolysiloxanes in which the organic group bonded to the silicon atom is an unsubstituted hydrocarbon group that does not contain an unsaturated aliphatic group as described above, and the unsubstituted hydrocarbon group is preferably a methyl group.

[0036] In the organopolysiloxane of component (b), the siloxane skeleton (-Si-O-Si-) may be linear, branched, or cyclic. The Si-H bond may be present in any siloxane unit within the molecule. Specifically, linear organopolysiloxanes shown in the following structural formulas 3 and 4 can be used as component (b).

[0037] [ka]

[0038] [ka]

[0039] In Structural Formula 3 and Structural Formula 4, R1 each independently represents an unsubstituted hydrocarbon group that does not contain an unsaturated aliphatic group, p represents an integer of 0 or greater, and q represents an integer of 1 or greater. Examples of the unsubstituted hydrocarbon group that does not contain an unsaturated aliphatic group include the same groups as those represented by R1 in Structural Formula 1 and Structural Formula 2, and a methyl group is preferred.

[0040] The blend amount of component (b) is preferably 0.1 to 20 parts by mass, and more preferably 0.3 to 10 parts by mass, per 100 parts by mass of component (a).

[0041] (c) component: a hydrosilylation catalyst; Examples of the hydrosilylation (addition curing) catalyst that can be used include platinum compounds. Specific examples include platinum carbonylcyclovinylmethylsiloxane complex and 1,3-divinyltetramethyldisiloxane platinum complex. The amount of component (c) added is preferably 0.0001 to 0.1 parts by mass, and more preferably 0.001 to 0.05 parts by mass, per 100 parts by mass of component (a).

[0042] (d) ingredient: set retarder; A curing retarder can be added to adjust the curing reaction rate of hydrosilylation (addition curing). Specific examples of curing retarders include 1,3,5,7-tetravinyltetramethylcyclotetrasiloxane, 2-methyl-3-butyn-2-ol, and 1-ethynyl-1-cyclohexanol. The amount of component (d) added is preferably 0.01 to 2 parts by mass, and more preferably 0.05 to 1 part by mass, per 100 parts by mass of component (a).

[0043] The elastic layer has a modulus of elasticity of 0.10 MPa or more and 0.40 MPa or less, and a silicone rubber-containing elastic layer with a modulus of elasticity in this range exhibits excellent flexibility. Therefore, when the fixing member according to the present disclosure is used as a heating member, its outer surface can reliably conform to the irregularities of the paper. Furthermore, when the fixing member according to the present disclosure is used as a pressure member, a sufficient nip width can be ensured. The modulus of elasticity of the elastic layer can be adjusted by adjusting the type and amount of component (a), the type and amount of component (b), the type and amount of component (c), and the type and amount of component (d).

[0044] The heat capacity per unit volume of the elastic layer is 1.7MJ / m 3 ·K. The heat capacity per unit volume is preferably less than 1.7 MJ / m 3 If it is less than ·K, the fixing member is heated quickly, which contributes to shortening the FPOT.

[0045] The thickness of the elastic layer is preferably 100 μm or more. When the fixing member is a fixing belt having an endless belt shape, the thickness of the elastic layer is more preferably 200 μm or more and 600 μm or less. By setting the thickness of the elastic layer within this range, the above-mentioned functions of the elastic layer can be more reliably exhibited.

[0046] [surface] The surface layer may be, for example, a fluororesin layer, specifically a layer containing one of the fluororesins listed below. Examples of fluororesins include tetrafluoroethylene-perfluoro(alkyl vinyl ether) copolymer (PFA), polytetrafluoroethylene (PTFE), and tetrafluoroethylene-hexafluoropropylene copolymer (FEP). Furthermore, the surface layer may contain a filler to improve thermal properties and abrasion resistance, as long as the filler does not impair moldability or toner releasability.

[0047] The thickness of the surface layer is preferably 10 μm or more and 100 μm or less. If the thickness of the surface layer is 10 μm or more, sufficient durability is obtained. Furthermore, if the thickness of the surface layer is 100 μm or less, the excellent flexibility of the silicone rubber-containing elastic layer is easily utilized.

[0048] The method for forming the surface layer is not particularly limited, and the following methods can be used, for example: a method in which a fluororesin molded into a tube is coated on the silicone rubber-containing elastic layer via an adhesive layer; or a method in which fluororesin fine particles are coated directly or in a solvent to form a paint on the silicone rubber-containing elastic layer, followed by drying and heat melting. These methods will be described in more detail below.

[0049] First, the formation of a surface layer by coating with a fluororesin tube will be described. The inner surface of the fluororesin tube can be activated in advance by treatment with sodium, excimer laser, ammonia, or the like, to improve adhesion. FIG. 2 is a schematic diagram illustrating an example of a process for coating a silicone rubber-containing elastic layer 2 with a fluororesin tube as a surface layer 4 via an adhesive layer 3. Specifically, an adhesive is applied to the surface of the silicone rubber-containing elastic layer 2 to form the adhesive layer 3. The outer surface of this adhesive layer 3 is coated with a fluororesin tube as the surface layer 4, and then laminated.

[0050] The adhesive preferably uses an addition-curing silicone rubber containing a self-adhesive component. Specifically, the addition-curing silicone rubber may contain an organopolysiloxane having multiple alkenyl groups, typically vinyl groups, in the molecular chain, a hydrogenorganopolysiloxane, and a platinum compound as a crosslinking catalyst. The addition-curing silicone rubber cures through an addition reaction. Known adhesives made of such addition-curing silicone rubbers may be used.

[0051] While this is not necessary when the substrate 1 is a shape-retaining core, when using a thin substrate such as a resin belt or metal sleeve used in a fixing belt, it is preferable to fit the substrate 1 onto a core to prevent deformation during processing. The method for coating the fluororesin tube is not particularly limited, and methods such as coating with an adhesive as a lubricant or expanding the fluororesin tube from the outside and coating it can be used. After coating, excess adhesive remaining between the silicone rubber-containing elastic layer 2 and the fluororesin tube can be squeezed out and removed using a means not shown. The thickness of the adhesive layer 3 after squeezing out is preferably 20 μm or less. A thickness of 20 μm or less of the adhesive layer can easily suppress an increase in the hardness of the fixing member, and when used as a heating member, it has excellent conformability to paper irregularities. When used as a pressure member, it is easy to obtain a good fixed image without narrowing the fixing nip width. Next, the adhesive layer 3 is hardened by heating for a predetermined time using a heating means such as an electric furnace, and both ends are processed to the desired length as needed to obtain a fixing member according to the present disclosure.

[0052] Next, the formation of a surface layer by fluororesin coating will be described. Fluororesin coating processes for forming the surface layer can be performed using methods such as electrostatic application of fluororesin microparticles or spray coating of fluororesin paint. When using electrostatic application, first, fluororesin microparticles are electrostatically applied to the inner surface of a mold, and the mold is heated to a temperature above the melting point of the fluororesin to form a thin film of fluororesin on the inner surface of the mold. After this, the inner surface is subjected to an adhesive treatment, a substrate is inserted, and an addition-curable liquid silicone rubber mixture containing at least metal silicon powder having an aspect ratio of 1.4 to 2.5 and an angle of repose of 35 to 52 degrees, and, for example, an addition-curable liquid silicone rubber, is injected between the substrate and the fluororesin, and the mixture is cured and then demolded to obtain a fixing member according to the present disclosure.

[0053] [Method of manufacturing the fixing member] The method for manufacturing a fixing member according to the present disclosure includes, for example, the following elastic layer forming step. A step of heat-curing the layer of addition-curing liquid silicone rubber mixture formed on the outer peripheral surface of the substrate to form a silicone rubber-containing elastic layer having an elastic modulus of 0.10 MPa or more and 0.40 MPa or less.

[0054] The method for manufacturing a fixing member according to the present disclosure may also include the following steps. A step of preparing an addition-curable liquid silicone rubber mixture containing at least metallic silicon powder and the above components (a) to (c).

[0055] In the manufacturing method of the present disclosure, the order of the above steps can be set as appropriate, and these steps can also be performed simultaneously (in parallel). When forming the silicone rubber-containing elastic layer and the surface layer, the above-mentioned methods for forming the silicone rubber-containing elastic layer and the surface layer can be used.

[0056] <Fixing device> The fixing device according to the present disclosure includes the fixing member according to the present disclosure. Specifically, the fixing device is a fixing device used in an electrophotographic image forming apparatus, in which the fixing member according to the present disclosure is arranged as a fixing belt, a fixing roller or a fixing film, and / or a pressure belt, a pressure roller or a pressure film. Examples of electrophotographic image forming apparatuses include electrophotographic image forming apparatuses having a photoreceptor, a latent image forming unit, a unit for developing the formed latent image with toner, a unit for transferring the developed toner image to a recording material, and a unit for fixing the toner image on the recording material.

[0057] An example of such a fixing device is shown in Figure 3. In Figure 3, reference numeral 5 denotes an endless fixing belt, inscribed in a belt guide member 6 and a stay 7 with a margin of circumferential length. Reference numeral 8 denotes a heater, which has a heater substrate made of alumina, ceramic, or the like, coated with an electrically resistive material such as silver-palladium (Ag / Pd) that generates heat when an electric current flows through it, in a linear or strip-like layer by screen printing or the like. A glass coating layer approximately 10 μm thick is then formed on top of this to protect and insulate the electrically resistive material. A thermistor is attached to the backside of the heater substrate, and power to the electrically resistive material is controlled according to the temperature detected by this thermistor, thereby maintaining the surface temperature of the fixing belt 5 at a temperature suitable for fixing.

[0058] The pressure roller 9 is in pressure contact with the heater 8 via the fixing belt 5, and is driven to rotate by a pressure roller drive means. The pressure roller 9 is driven to rotate, and the fixing belt 5 rotates accordingly. A recording material such as paper on which an unfixed image has been formed is sandwiched and conveyed between the fixing belt 5 and the pressure roller 9, whereby the unfixed image is heated and fixed to the recording material. This fixing device is a fixing device of a relatively low pressure type.

[0059] Although a fixing device including a fixing belt and a pressure roller is given as an example of the fixing member here, the fixing device according to the present disclosure is not limited to that shown in FIG. 3 as long as it includes the fixing member according to the present disclosure as a fixing belt, a fixing roller, or a fixing film, and / or a pressure belt, a pressure roller, or a pressure film. [Example]

[0060] The present disclosure will now be described in more detail using examples. In the following examples, "Example 5" should be read as "Reference Example." First, the method for measuring the aspect ratio and angle of repose of metal silicon powder will be described. As mentioned above, the aspect ratio of metal silicon powder was determined by measuring the major and minor axes of 100 or more powder particles observed with a scanning electron microscope (SEM), calculating the major axis / minor axis ratio, and taking the arithmetic average. As mentioned above, the angle of repose was also measured using a "Powder Tester PT-X" (trade name, manufactured by Hosokawa Micron Corporation) under the following conditions. Sieve: mesh size 150μm, wire diameter 100μm ·Amplitude: 0.5mm Vibration time: 1800 seconds or more (until the metal silicon powder falls in a 360° circle around the plate) Slowdown time: 10 seconds For example, the elastic layer of the fixing member can be baked to decompose and remove the silicone rubber in the elastic layer, thereby recovering the metallic silicon powder from the elastic layer. The angle of repose of the recovered metallic silicon powder can then be measured using the method described above. According to the inventors' investigations, the angle of repose of the metallic silicon powder recovered from the elastic layer using the method described above is the same as the angle of repose of the raw metallic silicon powder.

[0061] [Example 1] (1) Rounding of metal silicon powder 100 g of metal silicon powder (product name: #350WB, manufactured by Kinseimatec Co., Ltd.) was placed in a hybridization system NHS-1 (product name, manufactured by Nara Machinery Co., Ltd.) and rotated at a peripheral speed of 100 m / s (rotation speed 8300 min -1 The powder was then treated in an inert argon atmosphere for 15 minutes. The aspect ratio of the recovered silicon metal powder was 1.5 and the angle of repose was 40 degrees.

[0062] (2) Preparation of addition-curing liquid silicone rubber mixture First, as component (a), an organopolysiloxane (viscosity 5000 mm) having vinyl groups, which are unsaturated aliphatic groups, only at both ends of the molecular chain and having methyl groups as unsubstituted hydrocarbon groups containing no other unsaturated aliphatic groups was used. 2 100 parts by mass of PEG-100 / s (hereinafter referred to as "Vi") was prepared. Next, 183.5 parts by mass of the metallic silicon powder obtained in (1) was weighed out and added to Vi. Next, 0.10 parts by mass of 1,3,5,7-tetravinyltetramethylcyclotetrasiloxane (trade name: SIT7900.0, manufactured by Gelest, Inc.), a cure retarder, as component (d) was added to the mixture of Vi and metal silicon powder. Next, 0.03 parts by mass of platinum carbonylcyclovinylmethylsiloxane complex (trade name: SIP6829.2, manufactured by Gelest, Inc.), a hydrosilylation catalyst, as component (c) was added to the mixture of Vi, metal silicon powder, and cure retarder. Furthermore, as component (b), a silicone polymer (viscosity 30 mm) having a linear siloxane skeleton and having active hydrogen bonded to silicon only in the side chain is used. 2 1.5 parts by mass of SiH (V / s, hereafter referred to as "SiH") was weighed out. The weighed SiH was added to a mixture of Vi, metal silicon powder, cure retarder, and platinum catalyst, and the mixture was thoroughly mixed to obtain an addition-cure liquid silicone rubber mixture containing 43% metal silicon powder by volume.

[0063] (3) Fabrication of the fixing belt Next, a fixing belt was produced using the resulting addition-curing liquid silicone rubber mixture as follows. An electroformed nickel endless sleeve with an inner diameter of 30 mm, a width of 400 mm, and a thickness of 40 μm was prepared as the substrate. During the series of manufacturing processes, the endless sleeve (endless sleeve) was handled with a core inserted inside.

[0064] First, a primer (product name: DY39-051 A / B, manufactured by DuPont Toray Specialty Materials Co., Ltd.) was applied uniformly to the outer peripheral surface of the substrate. After the solvent was dried, the substrate was baked for 30 minutes in an electric furnace at 160°C. Next, an addition-cure liquid silicone rubber mixture was applied to the primer-treated substrate using the ring coating method to a thickness of 300 μm. The endless belt with this silicone rubber mixture applied was heated in an electric furnace at 160°C for 1 minute (primary curing), and then heated in an electric furnace at 200°C for 4 hours (secondary curing) to cure the silicone rubber mixture and form a silicone rubber-containing elastic layer containing metal silicon powder.

[0065] Next, while the surface of the resulting endless belt was rotated in the circumferential direction at a speed of 20 mm / sec, the surface of the silicone rubber containing the metal silicon powder was irradiated with ultraviolet light using an ultraviolet lamp installed 10 mm from the surface. The ultraviolet lamp used was a low-pressure mercury ultraviolet lamp (product name: GLQ500US / 11, manufactured by Toshiba Lighting & Technology Corporation), and irradiation was carried out for 6 minutes at room temperature in an air atmosphere.

[0066] Next, an addition-curing silicone rubber adhesive (product name: SE1819CV A / B, manufactured by DuPont-Toray Specialty Materials Co., Ltd.) was applied uniformly to the surface of the elastic layer of the endless belt to a thickness of 20 μm. A fluororesin tube (product name: KURANFLON-LT, manufactured by Kurabo Industries, Ltd.) with an inner diameter of 29 mm and a thickness of 30 μm was then layered on top of the adhesive. The belt was then uniformly pressed over the fluororesin tube to remove excess adhesive from between the elastic layer and the fluororesin tube until the adhesive was sufficiently thin. The resulting endless belt was heated in an electric furnace at 200°C for 1 hour to harden the adhesive, and the surface layer made of the fluororesin tube was fixed onto the elastic layer. Both ends of the resulting endless belt were cut to obtain a fixing belt with a width of 341 mm.

[0067] (4) Evaluation of the characteristics of the elastic layer of the fixing belt First, a primer treatment was performed on the substrate using the same method as the above-mentioned fixing belt production method, and then a 300 μm-thick elastic layer for evaluation (elastic layer after secondary curing) was formed using a ring coating method.

[0068] (4-1) Tensile modulus of elastic layer To confirm that the elastic layer had low hardness, the tensile modulus of the elastic layer was measured. Specifically, the elastic layer was cut out using a punching die (JIS No. 3 dumbbell type), and the rubber thickness near the center, which was the measurement point, was measured. Next, the cut-out elastic layer was tested using a tensile tester (product name: Strograph EII-L1, manufactured by Toyo Seiki Seisakusho, Ltd.) at a tensile speed of 500 mm / min at room temperature. The tensile modulus was determined by creating a graph from the measurement results with the sample strain on the horizontal axis and the tensile stress on the vertical axis, and the slope of the linear approximation of the measurement data in the strain range of 0 to 100%. As a result, the tensile modulus of the elastic layer was 0.30 MPa.

[0069] (4-2) Heat capacity per unit volume of the elastic layer The heat capacity per unit volume, CV, was calculated using the following formula: CV=Cp×ρ In the formula, Cp is the specific heat at constant pressure (J / kg K), ρ is the density (kg / m 3 ) where the low-pressure specific heat and density values ​​were determined by the following method.

[0070] Constant pressure specific heat Cp The constant pressure specific heat of the elastic layer was measured using a differential scanning calorimeter (trade name: DSC823e, manufactured by Mettler-Toledo). Specifically, aluminum pans were used for the sample and reference pans. First, a blank measurement was performed with both pans empty. The temperature was maintained at 15°C for 10 minutes, then the temperature was increased to 215°C at a rate of 10°C / min and maintained at 215°C for another 10 minutes. Next, measurements were performed using the same program using 10 mg of synthetic sapphire, whose low-pressure specific heat capacity was known, as a reference material. A 10 mg measurement sample, the same amount as the reference sapphire, was then cut from the elastic layer and placed in the sample pan. The same program was used. These measurement results were analyzed using the specific heat analysis software provided with the differential scanning calorimeter. The constant-pressure specific heat capacity (Cp) at 25°C was calculated from the average of five measurements. The constant-pressure specific heat capacity (Cp) of the silicone rubber-containing elastic layer was found to be 1.03 J / g·K.

[0071] ·Density ρ The density of the elastic layer was measured using a dry automatic density meter (product name: Accupyc 1330-01, manufactured by Shimadzu Corporation). 3 Using a sample cell of 1.0 mm, a sample was cut out from the elastic layer so as to fill 80% of the cell volume, the mass of this sample was measured, and then it was placed in the sample cell. This sample cell was set in the measurement section of the device, and after gas replacement using helium as the measurement gas, the volume measurement was carried out 10 times. The density of the sample was calculated from the mass of the sample and the measured volume for each measurement, and the average value was calculated. As a result, the density ρ of the silicone rubber-containing elastic layer was found to be 1.56 g / cm 3 It was.

[0072] The heat capacity per unit volume, CV, was calculated from the constant pressure specific heat, Cp, and density, ρ, of the silicone rubber-containing elastic layer, resulting in a value of 1.61 MJ / m 3 It was K.

[0073] (4-3) Thermal conductivity of the elastic layer in the thickness direction The thermal conductivity λ of the elastic layer in the thickness direction was calculated from the following formula. λ=α×Cp×ρ 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), Cp is the specific heat at constant pressure (J / kg K), ρ is the density (kg / m 3 ) where the constant pressure specific heat Cp and density ρ of the elastic layer were calculated by converting the values ​​obtained by the above-mentioned method into units. The thermal diffusivity in the thickness direction was calculated by the following method.

[0074] ·Thermal diffusivity α The thermal diffusivity in the thickness direction of the elastic layer was measured at room temperature (25°C) using a cyclic heating thermal property measurement device (product name: FTC-1, manufactured by ULVAC-RIKO, Inc.). Sample pieces with an area of ​​8 × 12 mm were cut from the elastic layer with a cutter to prepare a total of five samples, and the thickness of each sample was measured. Next, a total of five measurements were performed on each sample, and the average value was calculated. The unit-converted specific heat at constant pressure Cp (J / kg K) and density ρ (kg / m 3 ), and the measured thermal diffusivity α(m 2 / s), the thermal conductivity λ of the silicone rubber-containing elastic layer was calculated to be 0.9 W / m·K.

[0075] (5) Pressure resistance durability evaluation of the elastic layer of the fixing belt First, a 50 mm x 50 mm stainless steel plate (reference numeral 10 in Figure 4) was primed using the same method as used to prepare the fixing belt. Then, a 1 mm-thick elastic layer 2 (elastic layer after secondary curing) was formed by press molding using a mold. Four samples were fabricated, and the pressure resistance of each sample's elastic layer was evaluated using the jig shown in Figure 4. The evaluation conditions were a sample surface temperature of 240°C, a load of 15 N, and a pressing roller 11 (10 mm wide, 15 mm diameter) reciprocating in the direction indicated by the arrow in Figure 4. The average time until the elastic layer broke or plastically deformed was measured. No breakage or plastic deformation of the elastic layer 2 was observed even after 600 minutes, demonstrating excellent pressure resistance.

[0076] (6) Evaluation of fixing belt The fixing belt obtained in (3) above was installed in the fixing device of an office multifunction printer (product name: imageRUNNER ADVANCE C5051, manufactured by Canon Inc.). An image formation operation was then performed, forming a cyan solid image on 300,000 sheets of A4-sized paper. The fixing belt was then removed from the fixing device, and the appearance of the elastic layer (presence or absence of breakage, presence or absence of plastic deformation) was visually confirmed and evaluated according to the following criteria. The solid image on the 300,000th sheet was also visually observed, and the presence or absence of gloss unevenness due to the fixing process was evaluated according to the following criteria. [Evaluation criteria for the appearance of the elastic layer] Rank A: No destruction or plastic deformation of the elastic layer was observed. Rank B: Destruction and plastic deformation of the elastic layer were observed. [Image quality evaluation criteria] Rank A: No uneven gloss was observed. Rank B: Gloss unevenness was observed.

[0077] [Example 2] The metallic silicon powder was subjected to chamfering in the same manner as in Example 1, except that the treatment was carried out in air. The aspect ratio of the recovered metallic silicon powder was 1.5 and the angle of repose was 39 degrees. Figure 5 shows SEM images of the metallic silicon powder (a) before and (b) after the chamfering treatment. Next, except for using this metal silicon powder, an addition-curing liquid silicone rubber mixture containing 43% by volume of metal silicon powder was obtained in the same manner as in Example 1. Next, except for using the obtained addition-curing liquid silicone rubber mixture, an elastic layer and a fixing belt for evaluation were produced and evaluated in the same manner as in Example 1.

[0078] [Example 3] Peripheral speed 80m / s (rotation speed 6600min -1The metal silicon powder was subjected to chamfering in the same manner as in Example 1, except that it was treated in air at 1000 K for 5 minutes. The obtained metal silicon powder had an aspect ratio of 1.5 and an angle of repose of 46 degrees. An addition-curable liquid silicone rubber mixture containing 43% by volume of metal silicon powder was obtained in the same manner as in Example 1, except that this metal silicon powder was used and the amount of component (b) was 1.25 parts by mass. Next, an elastic layer and a fixing belt for evaluation were produced and evaluated in the same manner as in Example 1, except that the obtained addition-curable liquid silicone rubber was used.

[0079] [Example 4] A chamfered metal silicon powder with an aspect ratio of 1.5 and an angle of repose of 39 degrees was prepared in the same manner as in Example 2. An addition-curable liquid silicone rubber mixture containing 43% by volume of metal silicon powder was obtained in the same manner as in Example 1, except that this metal silicon powder was used and the amount of component (b) was 1.1 parts by mass. Next, an elastic layer and a fixing belt for evaluation were produced and evaluated in the same manner as in Example 1, except that the obtained addition-curable liquid silicone rubber mixture was used.

[0080] [Example 5] Circumference speed 60m / s (rotation speed 5000min -1 ) in air for 3 minutes, the metal silicon powder was subjected to chamfering in the same manner as in Example 1. The obtained metal silicon powder had an aspect ratio of 1.5 and an angle of repose of 52 degrees. Next, an addition-curable liquid silicone rubber mixture containing 43% by volume of metal silicon powder was obtained in the same manner as in Example 1, except that this metal silicon powder was used and the amount of component (b) was 1.1 parts by mass. Next, an elastic layer and a fixing belt for evaluation were produced and evaluated in the same manner as in Example 1, except that the obtained addition-curable liquid silicone rubber mixture was used.

[0081] [Example 6] An addition-curable liquid silicone rubber mixture containing 43% by volume of metal silicon powder was obtained in the same manner as in Example 3, except that the amount of component (b) was 1.4 parts by mass. Next, an elastic layer and a fixing belt for evaluation were produced and evaluated in the same manner as in Example 1, except that the obtained addition-curable liquid silicone rubber mixture was used.

[0082] [Example 7] The metal silicon powder was subjected to a chamfering treatment in the same manner as in Example 1. The collected metal silicon powder was classified, and metal silicon powder with particle sizes in the range of 5 to 10 μm was collected. This metal silicon powder had an aspect ratio of 1.9 and an angle of repose of 41 degrees. An addition-curable liquid silicone rubber mixture containing 43% by volume of metal silicon powder was obtained in the same manner as in Example 1, except that this metal silicon powder was used and the amount of component (b) was changed to 1.3 parts by mass. An elastic layer and a fixing belt for evaluation were produced and evaluated in the same manner as in Example 1, except that the obtained addition-curable liquid silicone rubber mixture was used.

[0083] [Example 8] The metal silicon powder was subjected to a chamfering treatment in the same manner as in Example 1. The collected metal silicon powder was classified, and metal silicon powder with a particle size of 10 μm or more was collected. The aspect ratio of this metal silicon powder was 2.2 and the angle of repose was 43 degrees. An addition-curable liquid silicone rubber mixture containing 43% by volume of metal silicon powder was obtained in the same manner as in Example 1, except that this metal silicon powder was used and the amount of component (b) was 1.3 parts by mass. An elastic layer and a fixing belt for evaluation were produced and evaluated in the same manner as in Example 1, except that the obtained addition-curable liquid silicone rubber mixture was used.

[0084] [Comparative Example 1] An addition-curable liquid silicone rubber mixture containing 43% by volume of metal silicon powder was obtained in the same manner as in Example 1, except that metal silicon powder (product name: #350WB, aspect ratio 1.5, angle of repose 55°, manufactured by Kinsei Matec Co., Ltd.) was used without corner reduction and the amount of component (b) was 1.1 parts by mass. An elastic layer for evaluation and a fixing belt were prepared and evaluated in the same manner as in Example 1, except that the obtained addition-curable liquid silicone rubber mixture was used. In the evaluation of this comparative example as a fixing belt, a portion of the elastic layer broke after the 10,000th image was formed, so the evaluation was discontinued. Therefore, image quality evaluation was not performed.

[0085] Comparative Example 2 Except for changing the amount of component (b) to 1.4 parts by mass, an addition-curable liquid silicone rubber mixture containing 43% by volume of metal silicon powder was obtained in the same manner as in Comparative Example 1. Except for using the obtained addition-curable liquid silicone rubber mixture, an elastic layer and a fixing belt for evaluation were produced and evaluated in the same manner as in Example 1.

[0086] Table 1 shows the evaluation results of Examples 1 to 8 and Comparative Examples 1 and 2.

[0087] [Table 1]

[0088] [Discussion of evaluation results] The evaluation results of Examples and Comparative Examples shown in Table 1 are described below. In Examples 1 to 8, the silicone rubber-containing elastic layer had a modulus of elasticity of 0.10 MPa or more and 0.40 MPa or less (approximately 15° or less in JIS A hardness (JIS K 6253)), demonstrating excellent flexibility. Furthermore, evaluation of the image quality of the fixing belt revealed that it conformed to the irregularities of the paper fibers of the recording material in the fixing nip, reducing uneven toner softening and melting, and producing high-quality images. Furthermore, the silicone rubber-containing elastic layer contained metal silicon powder with an aspect ratio of 1.4 to 2.5 and an angle of repose of 35° to 52°, and the pressure resistance durability of the elastic layer was excellent, lasting for 100 minutes or more. Furthermore, evaluation of the appearance of the elastic layer of the fixing belt revealed that no fracture or plastic deformation of the silicone rubber-containing elastic layer was observed in the non-paper-passing areas of the fixing belt even after 300,000 sheets were passed through the belt, demonstrating its excellent durability.

[0089] The metal silicon powder contained in the elastic layer of the fixing belt according to Comparative Example 1 was not subjected to corner chamfering, and the angle of repose exceeded 52 degrees. As a result, in a pressure resistance durability test, the time until fracture or plastic deformation occurred for this elastic layer was 10 minutes, which was extremely short compared to the time for the elastic layers according to the Examples. On the other hand, the elastic layer according to Comparative Example 2 had relatively excellent pressure resistance durability. However, since the elastic modulus of the elastic layer exceeded 0.40 MPa, it had poor flexibility, and the fixing belt was unable to follow the irregularities caused by the fibers of the paper, which is the recording material, and uneven gloss was observed, which was thought to be due to uneven softening and melting of the toner. [Explanation of symbols]

[0090] 1‥‥Base 2. Silicone rubber-containing elastic layer

Claims

1. A fuser member having a substrate and an elastic layer on the substrate, the elastic layer contains silicone rubber and metal silicon powder dispersed in the silicone rubber; The elastic layer has an elastic modulus of 0.10 MPa or more and 0.40 MPa or less, and The fixing member is characterized in that the metal silicon powder has an aspect ratio of 1.4 or more and 2.5 or less, and an angle of repose of 35 degrees or more and 46 degrees or less.

2. 2. The fixing member according to claim 1, wherein the content of the metal silicon powder in the elastic layer is 15% or more and 55% or less by volume with respect to the elastic layer.

3. The heat capacity per unit volume of the elastic layer is 1.7 MJ / m ３ 3. The fixing member according to claim 1, wherein the surface roughness is less than K.

4. A fixing device comprising the fixing member according to any one of claims 1 to 3.

5. An electrophotographic image forming apparatus comprising the fixing device according to claim 4.

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