JP2006048028A - Member for fixation, and device and method for fixation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a member for fixation which stops paper twine and toner offsetting and has a rubber release layer with superior toner releasing properties for an oilless fixation type wax-containing toner. <P>SOLUTION: Disclosed is the member for fixation which has the rubber release layer containing a mixture of fluororubber and dimethyl silicone rubber as a surface layer, the rubber release layer being in structure wherein dimethyl silicone rubber form dispersion phases in island shapes in a continuous phase of the fluororubber. The mean particle size of the dispersion phases in section of the rubber release layer is ≤20 μm, and the mixing ratio of the fluororubber and dimetyl silicone rubber is 20:80 to 80:20 by volume. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is used in the field of fixing technology in electrophotographic image forming apparatuses such as copying machines and LBPs, and in particular, a fixing member having a rubber release layer capable of fixing toner onto a recording material by an oilless fixing method. The present invention relates to a fixing device and a fixing method.

  In an electrophotographic image forming apparatus, a fixing member is incorporated in order to heat and fix a toner image formed on a recording material such as paper. Such a fixing member is required to have toner releasability. The toner releasability is how the toner does not adhere to the surface of the fixing member when the toner image electrostatically formed on the recording material is fixed by heat and pressure. When the toner adheres to the surface of the fixing member, that is, when toner offset occurs, the toner image formed on the recording material is partially chipped, or the offset toner is re-fixed on the next recording material. In some cases, the image may deteriorate. Therefore, it is important for the performance of the member to use a material having excellent toner releasability for the surface of the fixing member, that is, the release layer.

  As such a fixing member, a member in which at least one release layer is formed on the outer periphery of a cylindrical shaft and the release layer is formed of a fluororesin is generally used. A fluororesin has a low surface energy, is non-adhesive, and has excellent toner releasability. However, since it is a resin, the hardness is high, and when fixing an electrostatically formed toner image by heat and pressure, the toner particles are crushed more than necessary, and fine lines may spread and overlap, It may be difficult to obtain high-quality images, such as making it difficult to read small characters.

  On the other hand, those having a release layer formed of rubber, which is an elastic body, are more flexible than resins, and have the advantage that toner particles are not crushed more than necessary and high-quality images can be easily obtained. However, in general, rubber has a higher surface energy than a fluororesin and may be inferior in toner releasability. In particular, in color oil-less fixing, only a fluororesin is practically used as a material for the release layer, and a fixing having a release layer having rubber (hereinafter also referred to as “rubber release layer”). The material for use has not been put to practical use until now. In order to obtain a high-quality image, a release layer having a flexible rubber is desired instead of a release layer having a hard resin.

  Since the fixing member is used at a high temperature of about 200 ° C., the rubber used for the release layer is required to have heat resistance. Examples of such heat-resistant rubber types include fluorine rubber and silicone rubber.

  The fluororubber is a polyamine cross-link by adding a cross-linking agent, a cross-linking aid or a reinforcing compounding agent to various fluoro rubber polymers (hereinafter also referred to as fluoropolymer) composed of partially fluorinated hydrocarbon chains, or A rubber which is an elastic body is formed by forming a three-dimensional network structure by crosslinking such as polyol crosslinking or organic peroxide crosslinking.

  Until now, fluoro rubber has been mainly used as a release layer of an oil coating system for supplying a modified silicone oil from the outside in a color machine. The kind of fluoropolymer includes a vinylidene fluoride-hexafluoropropylene binary copolymer, or a vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, and a metal-containing filler, or Those obtained by blending reinforcing fillers with polyamine crosslinking or polyol crosslinking are mainly used.

  Silicone rubber is an addition reaction of raw rubber such as methyl vinyl siloxane or a polymer consisting of methyl phenyl vinyl siloxane units in which a part of the methyl group is substituted with a phenyl group, and various fillers as necessary. A rubber which is an elastic body is formed by forming a three-dimensional network structure by crosslinking such as crosslinking or organic peroxide crosslinking. In general, since silicone rubber is excellent in heat resistance, it is mainly used as a heat conductive elastic body layer under the release layer. The release layer has been mainly used in an oil coating system for supplying dimethyl silicone oil from the outside in a color machine.

  Recently, in order to ensure the releasability of the toner, a wax having a release-releasing effect is internally added to the toner particles, and the oil-less fixing method in which no oil is applied from the outside as described above has been developed. Practical use in mold layers.

  If fluororubber is used in the release layer instead of fluororesin for the purpose of obtaining a high-quality image, the affinity between the wax and fluororubber in the toner is low, and the release assist effect by the wax is not fully exhibited. For this reason, paper wrapping or toner offset caused by the toner not being peeled off from the release layer may occur. Also, when dimethyl silicone rubber is used for the release layer, the affinity between the wax in the toner particles and the dimethyl silicone rubber is high, but the affinity is too high, which has some adverse effect on the toner release properties. In the same manner as above, paper wrapping or toner offset may occur.

  In oilless fixing for color machines, the toner is a toner having toner particles containing at least a wax (hereinafter also referred to as a wax-containing toner), and is on the side in contact with an unfixed toner image on a recording material in a fixing device. An image recording apparatus has been proposed in which a release layer made of fluororubber having a high affinity for wax is provided on the surface of a fixing member (see, for example, Patent Document 1). Further, the toner is a toner having toner particles containing at least a binder resin, a colorant, and a wax, the weight average molecular weight (Mw) of the wax is 400 to 4000, and the number average molecular weight (Mn) is 200 to 4000, and a release layer provided on the outermost surface of the heat-fixing member is formed by a mixture of fluororubber and a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, and the release layer. There has been proposed a fixing device in which the contact angle of the mold layer with respect to water is adjusted within a range of 80 to 103 ° (see, for example, Patent Document 2).

  In Patent Document 1, a release layer made of fluororubber having a high affinity for wax is proposed, but further improvement in toner release properties is desired.

Moreover, in the said patent document 2, the mold release layer which consists of a mixture of fluororubber and a tetrafluoroethylene perfluoroalkyl vinyl ether copolymer is proposed in order not to impair the affinity with wax. However, this is not rubber alone but a mixture of rubber and resin, and its flexibility may be lower than that of rubber alone.
JP 2000-242115 A Japanese Patent No. 3055119

  An object of the present invention is to provide a fixing member having a rubber release layer that does not cause toner offset and has excellent toner release properties with respect to wax-containing toners used in oilless fixing systems. Another object of the present invention is to provide a fixing method and a fixing device provided with such a fixing member.

  The above object of the present invention is achieved by the following invention.

(1) As a surface layer, a rubber release layer having a mixture of fluororubber and dimethylsilicone rubber is formed, and the rubber release layer has a disperse phase in which the dimethylsilicone rubber is dispersed in an island shape in the continuous phase of the fluororubber. It has a formed structure, the average particle size of the dispersed phase in the cross section of the rubber release layer is 20 μm or less, and the blending ratio of the fluororubber and the dimethylsilicone rubber is 20:80 to 20 by volume ratio. The fixing member is in a range of 80:20. By finely dispersing dimethyl silicone rubber in fluoro rubber, the affinity with wax can be increased moderately.

(2) The fixing member according to (1), wherein the fluororubber is a terpolymer of vinylidene fluoride-tetrafluoroethylene-perfluoroalkyl vinyl ether.

(3) The fixing member according to (1) or (2), wherein the rubber release layer contains a silicone surfactant. The dispersibility of the dimethyl silicone rubber in the fluoropolymer can be improved by adding a silicone surfactant having an affinity for both the fluoropolymer and the dimethyl silicone rubber.

(4) The fixing member according to (3), wherein the silicone surfactant has a structure in which a polydimethylsiloxane portion having a hydrophobic property and a polyoxyalkylene portion having a hydrophilic property are alternately repeated. By using a silicone-based surfactant having such a structure, the effect of improving dispersibility can be further enhanced.

(5) The fixing amount according to (3) or (4), wherein the amount of the silicone-based surfactant is 0.1 to 5.0% by mass with respect to the total mass of the fluororubber and dimethylsilicone rubber. It is a member. By setting it as this range, the dispersibility of dimethyl silicone rubber can be improved.

(6) The fixing member according to any one of (1) to (5), wherein the fluorine rubber and dimethyl silicone rubber in the rubber release layer are both organic peroxide-crosslinked. The cross-linking of the fluoro rubber and dimethyl silicone rubber can be unified, and the strength of the blend rubber can be increased.

(7) The fixing member according to (6), wherein the organic oxide crosslinking is performed simultaneously on the fluororubber and the dimethylsilicone rubber. At the same time, when organic peroxide crosslinking is performed, crosslinking is also performed at the interface between the continuous phase and the dispersed phase, so that the strength of the blend rubber can be further increased.

(8) The fixing member according to any one of (1) to (7), wherein the fixing member is in the form of a roller.

(9) The fixing member according to any one of (1) to (7), wherein the fixing member is in the form of a belt.

(10) An oilless fixing type fixing device in which the fixing member described in any one of (1) to (9) is disposed. By using such a fixing device, a high-quality image can be obtained.

(11) The oilless fixing type fixing device according to (10), wherein the fixing member is a fixing roller.

(12) The oilless fixing type fixing device according to (10), wherein the fixing member is a fixing belt.

(13) The oilless fixing type fixing device according to (10), wherein the fixing member is a pressure roller.

(14) The oilless fixing type fixing device according to (10), wherein the fixing member is a pressure belt.

(15) An oil-less fixing method in which a toner image is fixed on a transfer material using the fixing device described in any one of (10) to (14). By using such a fixing method, a high-quality image can be obtained.

  When the fixing member of the present invention is incorporated in a fixing device and used, it does not cause paper wrapping or toner offset with respect to a wax-containing toner of an oilless fixing method, and is excellent in toner releasability and flexibility. Therefore, an oilless fixing type electrophotographic image forming apparatus provided with a fixing device incorporating the fixing member of the present invention has a high quality toner image.

  As a means for appropriately increasing the wax affinity of fluororubber, it is conceivable to disperse dimethyl silicone rubber in an island shape. By dispersing dimethyl silicone rubber having a high affinity for wax in a fluoro rubber having a low affinity for wax, the wax affinity of the fluorine rubber can be increased. Further, even when dimethyl silicone rubber is dispersed in islands in fluoro rubber, when the average particle size of the dispersed phase in the cross section of the rubber release layer exceeds 20 μm, dimethyl silicone rubber does not exist on the rubber surface, This is not desirable because the wax affinity may not be improved. Further, when the average particle size of the dispersed phase in the section of the rubber release layer exceeds 20 μm for a wax-containing toner generally having an average particle size of 10 μm or less, the wax affinity of the fluororubber is made uniform. This is not desirable because it cannot be increased. From the viewpoint of ease of processing, the average particle size of the dispersed phase on the cross section and surface of the rubber release layer is preferably 1 μm or more.

  In the present invention, the average particle size of the dispersed phase is measured as follows.

  For each particle forming a dispersed phase in a cross section perpendicular to the surface of the rubber release layer, fix the largest diameter part of the particle as the major axis direction and renew the minor axis so that the particle areas are equal. The average value of the length of the long axis and the length of the short axis when set to be elliptical by setting to is the particle diameter of the particle. Further, the particle diameter of 100 randomly selected particles was measured, and the average value was obtained as the average particle diameter of the dispersed phase in the cross section of the rubber release layer. Here, the dispersion state of the fluoro rubber and dimethyl silicone rubber in the rubber release layer was accelerated using a scanning electron microscope (SEM, JSM-5910LV type manufactured by JEOL Ltd.) equipped with an electron probe microanalyzer (EPMA). Voltage: 20 kV, measurement mode: high vacuum mode, measurement magnification: 300 times, detector: energy dispersive type (EDS), mapping element: element mapping by F, Si. Further, the average particle diameter of the dispersed phase on the surface of the rubber release layer can be determined using the same measurement method.

  The blending ratio of fluororubber and dimethylsilicone rubber is 20:80 to 80:20 in volume ratio, and if dimethylsilicone rubber is less than 20/100 in volume ratio, the affinity with wax is sufficiently enhanced. It is not desirable because it cannot be done. On the other hand, when the volume ratio of dimethyl silicone rubber exceeds 80/100, the affinity with wax may be excessively increased, which may adversely affect toner releasability.

  Conventionally, as an attempt to disperse dimethylsilicone rubber in fluororubber, simply mixing dimethylsilicone rubber with fluororubber makes the dispersion state rough because the affinity between the two is low, and the dispersed phase in the cross section of the rubber release layer In many cases, the particle size of the resin was on the order of several hundred μm. Therefore, in the present invention, a vinylidene fluoride-tetrafluoroethylene-perfluoroalkyl vinyl ether terpolymer having an ether group is selected as the polymer type of the fluororubber, and both the fluoropolymer and the dimethyl silicone rubber are selected. It has been found that the dispersibility of the dimethyl silicone rubber can be further improved by blending an affinity silicone-based surfactant.

  The silicone-based surfactant is preferably a nonionic surfactant having a hydrophobic group composed of dimethylpolysiloxane and a hydrophilic group composed of polyoxyalkylene. Since the silicone-based surfactant has a siloxane skeleton, it has low volatility and excellent thermal stability, and is therefore suitable for use in a fixing member used at high temperatures. In addition, it exhibits a certain degree of solubility in a ketone-based organic solvent capable of dissolving both the fluoropolymer and the dimethyl silicone rubber, so that it can function as a surfactant for both.

  In the silicone-based surfactant compounded in the present invention, the hydrophobic dimethylpolysiloxane portion has a high affinity with dimethylsilicone rubber, and the hydrophilic polyoxyalkylene portion has an affinity with a fluoropolymer. It is considered that the dispersibility of dimethyl silicone rubber can be improved by functioning as a surfactant.

  The type of fluororubber polymer (also referred to as a fluoropolymer) used in the present invention is not particularly limited, but is a general vinylidene fluoride-hexafluoropropylene binary copolymer or vinylidene fluoride-hexa. The terpolymer of vinylidene fluoride-tetrafluoroethylene-perfluoroalkyl vinyl ether having an ether group is more suitable for the ether group of the silicone surfactant than the terpolymer of fluoropropylene-tetrafluoroethylene. Since it is considered that the affinity with the polyoxyalkylene is high, a terpolymer of vinylidene fluoride-tetrafluoroethylene-perfluoroalkyl vinyl ether is preferred in the present invention.

  The silicone surfactant used in the present invention is preferably a compound having a structure represented by the following formulas (1) to (3).

  That is, a side chain-modified silicone surfactant having a structure in which polyoxyalkylene is bonded to a side chain of a dimethylpolysiloxane skeleton represented by the following formula (1), a dimethylpolysiloxane skeleton represented by the following formula (2) A terminal-modified silicone surfactant having a structure in which polyoxyalkylene is bonded to the end of the polymer, and a copolymer having a structure in which dimethylpolysiloxane and polyoxyalkylene represented by the following formula (3) are alternately bonded. Type silicone surfactant. Among these, the copolymer type silicone surfactant represented by the formula (3) is preferable because it has a higher effect of dispersing dimethyl silicone rubber in the fluoropolymer. In the compounds having the structures represented by the following formulas (1) to (3), R is independently a substituted or unsubstituted alkyl group, and R ′ is independently a substituted or unsubstituted alkylene group. , A, b, m and n each independently represent a positive integer.

  The silicone surfactant content is preferably in the range of 0.1 to 5.0% by mass with respect to the total of the fluororubber and dimethylsilicone rubber because a sufficient effect of improving dispersibility is obtained. .

  Next, there is no particular limitation on the cross-linking of each of the fluororubber and dimethylsilicone rubber, but both are cross-linked at the interface between the continuous phase and the dispersed (island) phase by organic peroxide cross-linking. It is preferable because the strength of the blend rubber can be increased and a rubber release layer having excellent durability can be formed.

  Specifically, fluororubber is a type in which iodine or bromine is introduced at the molecular chain end or side chain, and crosslinking with an organic peroxide is performed by drawing out iodine or bromine atoms and allylic groups of the crosslinking aid. It is carried out by the radical reaction of The dimethyl silicone rubber is of a type in which a vinyl group is introduced into the terminal or side chain of the dimethylpolysiloxane skeleton, and the crosslinking with an organic peroxide is performed by a radical reaction to the vinyl group. However, in the present invention, the surface layer is formed by solution coating and then heated and crosslinked. However, organic peroxide crosslinking is cured by oxygen present in the air when subjected to atmospheric pressure hot air crosslinking such as oven crosslinking. Inhibition may occur. In order to block oxygen that causes curing inhibition, it is preferable to crosslink by immersing in heated oil such as silicone oil or fluorine oil. Silicone oil and fluorine oil have excellent heat resistance and are suitable for use at high temperatures. Silicone oil is more preferable because it can form a silicone polymer outermost layer on a fluororubber by chemical bonding (Japanese Patent Laid-Open No. 2003-215969).

  The fixing member having the rubber release layer of the present invention can be produced, for example, as follows. First, a fluoropolymer composed of a terpolymer of vinylidene fluoride-tetrafluoroethylene-perfluoroalkyl vinyl ether containing iodine or bromine in the molecule as a reactive group, and dimethylpolysiloxane containing a vinyl group as a reactive group The volume ratio of the silicone polymer is 50:50, triallyl isocyanurate as a crosslinking aid is 4.0% by mass with respect to the total of the fluoropolymer and the silicone polymer, and benzoyl peroxide as an organic peroxide is 3% as a crosslinking agent. 0.0% by mass and 1.0% by mass of silicone surfactant are dissolved in a ketone solvent to obtain a ketone solution. After the ketone-based solution is thoroughly stirred, a primer is uniformly applied in advance by blade coating or the like, and dried on a roller-like or belt-like substrate (an elastic layer formed thereon if necessary). Coating. Thereafter, it can be produced by immersing in heated dimethylsilicone oil and heating, followed by steps of primary crosslinking and secondary crosslinking in an oven. When the elastic layer is made of a heat conductive silicone rubber, the crosslinking agent and the crosslinking aid may migrate into the silicone rubber of the elastic layer and the content in the release layer may decrease. In view of the amount of the auxiliary agent transferred to the elastic layer silicone rubber, it is desirable to add several times the standard amount. In addition, what is necessary is just to use a well-known primer layer, Although the thickness is not specifically limited, Usually, it is about 1-10 micrometers.

  Sectional views of the layer structure of the fixing member thus obtained are shown in FIG. 1 (single layer structure) and FIG. 2 (two layer structure).

  In FIG. 1, the upper surface of a roller-like or belt-like substrate 1 has a structure in which fluororubber is a continuous phase and dimethylsilicone rubber is an island-like dispersed phase. A rubber release layer 2 having an average particle size of 20 μm or less is formed.

  The thickness of the rubber release layer may be appropriately determined as necessary, but it is usually preferably 10 μm or more in order to ensure sufficient scratch resistance and wear resistance. Moreover, it is desirable that it is 500 micrometers or less from points, such as thermal conductivity.

  FIG. 2 relates to a fixing member having a two-layer structure. First, a heat conductive elastic layer 3 made of a conventional silicone rubber or the like is formed on a roller-like or belt-like substrate 1. The rubber release layer 2 of the present invention is formed on the elastic layer 3.

  Examples of the silicone rubber polymer species used here include polydimethylsiloxane and polymethylphenylsiloxane. The thermally conductive elastic layer is preferably formed from a material in which a thermally conductive filler is blended. Such an elastic layer can be produced by a known method, for example, a method in which a silicone rubber material is injected into a mold and heat-cured, or a method in which a silicone polymer layer is formed by coating and cured in a heating oven or the like. it can.

  The thickness of the heat conductive elastic layer is preferably 50 μm or more for reasons such as ensuring followability to a recording material such as paper, and is preferably 5 mm or less from the viewpoint of thermal conductivity.

  In this case, as in the case of the fixing member having a single layer structure, the thickness of the rubber release layer may be determined as appropriate, and the preferred range is also the same.

  The fixing member of the present invention is not limited to the single-layer or two-layer fixing member described above, and may have a multilayer structure of three or more layers. A pressure belt or a pressure roller may be used.

  Next, the fixing device of the present invention will be described.

  The fixing device of the present invention is a fixing device used in an electrophotographic image forming apparatus, in which the fixing member is arranged as a fixing belt or a fixing roller and / or a pressure belt or a pressure roller. . The electrophotographic image forming apparatus includes a photosensitive member, a latent image forming unit, a developing unit for developing the formed latent image with toner, a transfer unit for transferring the developed toner image to a transfer material, and a transfer material And an electrophotographic image forming apparatus having fixing means for fixing the toner image.

  FIG. 3 shows a configuration diagram of an example of the fixing device of the present invention.

  In the fixing device, a fixing roller 11 which is a roller described on the upper side in FIG. 3 and a pressure roller 12 which is a roller described on the lower side are arranged. The fixing member of the present invention is used for at least one of the fixing roller 11 and the pressure roller 12. At the center of at least one of the fixing roller 11 and the pressure roller 12, heaters 4 and 4 'made of, for example, a halogen lamp are incorporated.

  The fixing roller 11 is rotationally driven in the direction of the arrow at a predetermined peripheral speed, and the pressure roller 12 is also rotationally driven in the direction of the arrow accordingly. The toner image formed on the recording material 13 such as paper is fixed by the heat from the heaters 4 and 4 ′ and the nip pressure between the fixing roller 11 and the pressure roller 12.

  The toner fixing temperature is maintained at a set temperature by controlling the outputs of the heaters 4 and 4 ′ based on the temperature measured by the thermistor 14 on the surface temperature of the fixing roller 11. The surface temperature (fixing temperature) of the fixing roller 11 is not particularly limited, but is usually about 130 to 220 ° C.

  Here, the fixing device of the fixing and pressure roller is taken as an example, but the fixing device of the present invention uses the fixing member of the present invention as a fixing belt or a fixing roller and / or a pressure belt or a pressure roller. What is necessary is just to have and it is not restricted to what was shown in FIG.

  Hereinafter, details of the present invention will be described by way of examples. In addition, this invention is not limited at all by these Examples.

  The dispersion state of fluoro rubber and dimethyl silicone rubber was examined by performing element mapping with an electron probe microanalyzer (EPMA) using a scanning electron microscope (SEM) (SEM: JSM-5910LV type manufactured by JEOL Ltd.). , Acceleration voltage: 20 kV, measurement mode: high vacuum mode, measurement magnification: 300 times, detector: energy dispersive type (EDS), mapping element: F, Si).

The volume ratio, which is the blending ratio of fluororubber and dimethylsilicone rubber, was calculated from the blending amount of each, the specific gravity of fluororubber 1.8 g / cm ³ , and the specific gravity of dimethylsilicone rubber 1.0 g / cm ³ .

  The unfixed image of the wax-containing toner was created by removing the fixing device of the color printer “LBP-2510” (trade name) manufactured by Canon Inc. and outputting the image. A fixing device (FIG. 3) in which the fixing member of the present invention is incorporated is placed in the above-described LBP-2510 and the unfixed image is passed under the conditions that the fixing side surface temperature is set to 180 ° C. and the process speed is 90 mm / sec. Thus, an image after fixing was obtained.

<Example 1>
90.0 g of a fluoropolymer composed of a terpolymer of vinylidene fluoride-tetrafluoroethylene-perfluoromethyl vinyl ether containing iodine as a reactive group in the molecule (trade name: Daiel LT302, manufactured by Daikin Industries, Ltd.) 50.0 g of a silicone polymer composed of dimethylpolysiloxane containing a vinyl group as a reactive group, 17.0 g of triallyl isocyanurate (trade name: TAIC, manufactured by Nippon Kasei Co., Ltd.) as a crosslinking aid, and an organic peroxide as a crosslinking agent 11.0 g of benzoyl peroxide (25% water-containing product, manufactured by Kishida Chemical Co., Ltd.) and a copolymer-type silicone surfactant having a structure in which dimethylpolysiloxane and polyoxyalkylene are alternately and repeatedly bonded (trade name: FZ) -2207, manufactured by Nippon Unicar Co., Ltd.) The g, was dissolved in methyl isobutyl ketone 525ml a ketone solvent to give a ketone solution.

  A heat conductive elastic layer made of silicone rubber having a thickness of 1.5 mm is formed on an aluminum cylinder used as a substrate. A roller (outer diameter 35 mm) is obtained by uniformly applying and drying a primer (trade name: GLP-103SR, manufactured by Daikin Industries, Ltd.) in advance on the surface of the heat conductive elastic layer so as to have a thickness of 1 μm. On the outer periphery of the roller, the above prepared ketone-based solution is thoroughly stirred and then blade-coated so as to form a rubber release layer having a thickness after drying of 100 μm. Name: KF-96SS-300cs, manufactured by Shin-Etsu Chemical Co., Ltd.) for 1 hour for primary crosslinking. Subsequently, secondary fixing in an oven (180 ° C., 24 hours) was performed to finish the fixing member.

  This fixing member was used as a fixing roller 11 in a fixing device (FIG. 3) according to an embodiment of the present invention, and an unfixed image of wax-containing toner was passed through the fixing device.

  Further, a sample for analysis of the release layer rubber was prepared, and the surface and cross-sectional dispersion form of this sample were examined. As a result, both had a structure in which fluororubber was a continuous phase and dimethylsilicone rubber was dispersed in an island shape, and the average particle size of the dispersed phase in the cross section of the rubber release layer was 20 μm. The average particle size of the dispersed phase on the surface of the rubber release layer was 15 μm.

<Example 2>
Instead of immersing the rubber used in the rubber release layer in dimethylsilicone oil at 200 ° C. for 1 hour, use fluorine oil at 200 ° C. (trade name: demnum S-65, manufactured by Daikin Industries, Ltd.) for 1 hour. A fixing member was finished in the same manner as in Example 1 except that it was immersed and heated.

  This fixing member was used as a fixing roller 11 in a fixing device (FIG. 3), and an unfixed image of wax-containing toner was passed through.

  Further, a sample for analysis of the release layer rubber was prepared, and the surface and cross-sectional dispersion form of this sample were examined. As a result, both had a structure in which fluororubber was the continuous phase and dimethylsilicone rubber was the dispersed phase, and the average particle size of the dispersed phase in the cross section of the rubber release layer was 20 μm. The average particle size of the dispersed phase on the surface of the rubber release layer was 15 μm.

<Example 3>
36.0g fluoropolymer, 80.0g silicone polymer, 14.0g triallyl isocyanurate, 9.3g benzoyl peroxide, 1.2g silicone surfactant, 435ml methyl isobutyl ketone A fixing member was finished in the same manner as in Example 2 except that the solution was obtained.

  This fixing member was used as a fixing roller 11 in a fixing device (FIG. 3), and an unfixed image of wax-containing toner was passed through.

  Further, a sample for analysis of the release layer rubber was prepared, and the surface and cross-sectional dispersion form of this sample were examined. As a result, both had a structure in which fluororubber was the continuous phase and dimethylsilicone rubber was the dispersed phase, and the average particle size of the dispersed phase in the cross section of the rubber release layer was 20 μm. The average particle size of the dispersed phase on the surface of the rubber release layer was 20 μm.

<Example 4>
144.0 g of fluoropolymer, 20.0 g of silicone polymer, 19.7 g of triallyl isocyanurate, 13.1 g of benzoyl peroxide, 1.6 g of silicone surfactant, 615 ml of methyl isobutyl ketone, and ketone system A fixing member was finished in the same manner as in Example 2 except that the solution was obtained.

  This fixing member was used as a fixing roller 11 in a fixing device (FIG. 3), and an unfixed image of wax-containing toner was passed through.

  Further, a sample for analysis of the release layer rubber was prepared, and the surface and cross-sectional dispersion form of this sample were examined. As a result, both had a structure in which fluororubber was the continuous phase and dimethylsilicone rubber was the dispersed phase, and the average particle size of the dispersed phase in the cross section of the rubber release layer was 20 μm. The average particle size of the dispersed phase on the surface of the rubber release layer was 15 μm.

<Comparative Example 1>
18.0 g of fluoropolymer, 90.0 g of silicone polymer, 13.0 g of triallyl isocyanurate, 8.6 g of benzoyl peroxide, 1.1 g of silicone surfactant, 405 ml of methyl isobutyl ketone, and ketone system The fixing member was finished in the same manner as in Example 2 except that the solution was obtained.

  This fixing member was used as a fixing roller 11 in a fixing device (FIG. 3), and an unfixed image of wax-containing toner was passed through the fixing device.

  Further, a sample for analysis of the release layer rubber was prepared, and the surface and cross-sectional dispersion form of this sample were examined. As a result, the cross section had a structure in which fluororubber was the continuous phase and dimethylsilicone rubber was the dispersed phase, but the average particle size of the dispersed phase in the cross section of the rubber release layer was 40 μm. The average particle size of the dispersed phase on the surface of the rubber release layer was 25 μm.

<Comparative example 2>
Except for obtaining a ketone type solution except that 162.0 g of fluoropolymer, 10.0 g of silicone polymer, 20.6 g of triallyl isocyanurate, 13.8 g of benzoyl peroxide, and 645 ml of methyl isobutyl ketone were obtained. In the same manner as in No. 2, the fixing member was finished.

  This fixing member was used as a fixing roller 11 in a fixing device (FIG. 3), and an unfixed image of wax-containing toner was passed through the fixing device.

  Further, a sample for analysis of the release layer rubber was prepared, and the surface and cross-sectional dispersion form of this sample were examined. As a result, both had a structure in which fluororubber was the continuous phase and dimethylsilicone rubber was the dispersed phase, and the average particle size of the dispersed phase in the cross section of the rubber release layer was 20 μm. The average particle size of the dispersed phase on the surface of the rubber release layer was 15 μm.

<Comparative Example 3>
A fixing member was finished in the same manner as in Example 2 except that no silicone surfactant was added.

  This fixing member was used as a fixing roller 11 in a fixing device (FIG. 3), and an unfixed image of wax-containing toner was passed through the fixing device.

  Further, a sample for analysis of the release layer rubber was prepared, and the surface and cross-sectional dispersion form of this sample were examined. As a result, the cross section had a structure in which fluororubber was a continuous phase and dimethyl silicone rubber was a dispersed phase, but only the fluororubber was present on the surface. The average particle diameter of the dispersed phase in the cross section of the rubber release layer was 80 μm.

  Table 1 shows the blending ratios and the like of Examples 1 to 4 and Comparative Examples 1 to 3.

  Next, Table 2 shows the evaluation results of Examples 1 to 4 and Comparative Examples 1 to 3.

  In Examples 1 to 4, the blending ratio of the fluororubber (A) and the dimethyl silicone rubber (B) is in the range of (A) :( B) = 20: 80 to 80:20 by volume ratio, and The surface and cross section of the rubber release layer have a structure in which fluoro rubber is a continuous phase and dimethyl silicone rubber is a dispersed (island) phase. The average particle size of the dispersed phase is 20 μm on both the surface and the cross section of the rubber release layer. It is as follows. Then, using a fixing device using the fixing member as a fixing roller, when an unfixed image of wax-containing toner is passed, the toner releasability is good, and even after 10,000 sheets are passed, the image is fixed. No image omission due to toner offset was observed. The toner image when 10,000 sheets were passed also had a high image quality.

  On the other hand, Comparative Example 1 has a large proportion of dimethyl silicone rubber, and the surface and cross section of the rubber release layer have a structure in which fluoro rubber is a continuous phase and dimethyl silicone rubber is a dispersed (island) phase. The average particle size of the dispersed phase exceeds 20 μm in both the surface and the cross section of the rubber release layer. Then, when a fixing device using the fixing member as a fixing roller is used and an unfixed image of wax-containing toner is passed, the toner releasability is insufficient, and when 100 sheets are passed, an image after fixing is formed. Image omission due to toner offset occurred and the fixing performance was not satisfied. Next, Comparative Example 2 has a structure in which both the surface and the cross section of the rubber release layer have a structure in which fluororubber is a continuous phase and dimethyl silicone rubber is a dispersed (island) phase. Although the average particle diameter of the dispersed phase is 20 μm or less, the blending ratio of dimethyl silicone rubber is 10% by volume, which is smaller than those in Examples 1 to 4. When a non-fixed image of wax-containing toner is passed through a fixing device using the fixing member as a fixing roller, the toner releasability is insufficient and the first image after fixing is lost due to toner offset. Occurred and the fixing performance was not satisfied. In Comparative Example 3, dimethyl silicone rubber was not present on the surface of the rubber release layer, and the average particle size of the dispersed phase in the cross section of the rubber release layer was 80 μm. This fixing member was used as a fixing device. In the paper passing test for the unfixed image containing the wax-containing toner when incorporated, the toner releasability is insufficient as compared with Comparative Example 1, and the paper wrapping caused by the toner not being peeled off from the release layer on the first sheet is observed. Happened.

FIG. 4 is a cross-sectional view of a fixing member having a single layer structure. It is sectional drawing of the fixing member of 2 layer structure. 1 is a schematic configuration diagram of an embodiment of a fixing device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base material 2 Rubber release layer 3 Thermally conductive elastic layer 4, 4 'Heater (halogen lamp)
11 Fixing roller 12 Pressure roller 13 Recording material (paper)
14 Thermistor

Claims (15)

  As the surface layer, a rubber release layer having a mixture of fluoro rubber and dimethyl silicone rubber is formed, and the rubber release layer has a structure in which the dimethyl silicone rubber forms an island-like dispersed phase in the continuous phase of the fluoro rubber. The average particle size of the dispersed phase in the cross section of the rubber release layer is 20 μm or less, and the blending ratio of the fluororubber and the dimethylsilicone rubber is 20:80 to 80:20 in volume ratio. A fixing member having the above-described range.   The fixing member according to claim 1, wherein the fluororubber is a terpolymer of vinylidene fluoride-tetrafluoroethylene-perfluoroalkyl vinyl ether.   The fixing member according to claim 1, wherein the rubber release layer further contains a silicone surfactant.   The fixing member according to claim 3, wherein the silicone-based surfactant has a structure in which polydimethylsiloxane portions and polyoxyalkylene portions are alternately repeated.   The fixing member according to claim 3 or 4, wherein the amount of the silicone-based surfactant is 0.1 to 5.0 mass% with respect to the total mass of the fluororubber and the dimethylsilicone rubber.   The fixing member according to claim 1, wherein both the fluororubber and the dimethylsilicone rubber in the rubber release layer are crosslinked with an organic peroxide.   The fixing member according to claim 6, wherein the organic oxide crosslinking is performed simultaneously on the fluorine rubber and the dimethyl silicone rubber.   The fixing member according to claim 1, wherein the fixing member is in the form of a roller.   The fixing member according to claim 1, wherein the fixing member is in the form of a belt.   An oilless fixing type fixing device in which the fixing member according to claim 1 is disposed.   11. The oilless fixing type fixing device according to claim 10, wherein the fixing member is a fixing roller.   11. The oilless fixing type fixing device according to claim 10, wherein the fixing member is a fixing belt.   The oilless fixing type fixing device according to claim 10, wherein the fixing member is a pressure roller.   The oil-less fixing type fixing device according to claim 10, wherein the fixing member is a pressure belt.   An oil-less fixing method for fixing a toner image on a transfer material using the fixing device according to claim 10.

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