JPH0996986A - Fixing roller and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing roller comprising a core metal and a silicone rubber layer and having improved durability without giving bad influences on the fixing property by dispersing metal oxide particles having an extremely small average particle size in a silicone rubber. SOLUTION: This fixing roller is produced by directly forming a silicone rubber layer 2 containing metal oxide particles on the core metal 1 or forming the rubber layer with another layer interposed. The metal oxide particles are such fine particles having <=0.1μm average particle size that are prepared by dispersing metal alkoxide in the silicone rubber and effecting hydrolysis and polymn. condensation by a solgel method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roller used in a fixing section of, for example, an electrophotographic copying machine, a laser beam printer, a facsimile, and a method for manufacturing the roller.
However, the fixing roller of the present invention does not exclude its application to similar products such as a pressure roller and a conveying roller that utilize the same characteristics as the fixing roller, that is, elasticity and non-staining property.

[0002]

2. Description of the Related Art Generally, as a method for fixing an unfixed toner image on a transfer paper in an image forming apparatus such as an electrophotographic copying machine, a laser beam printer or a facsimile,
A method using a heating roller is used. This fixing method is a method of fixing the toner image on the transfer paper by passing the transfer paper on which the unfixed toner image is formed between two pressure-contact rollers and heating one or both of the rollers from the inside. is there. Of the two rollers, the roller that comes into contact with the unfixed toner image is called a fixing roller, and a heating source is usually arranged inside the fixing roller.

As the fixing roller, a metal cored bar provided with an elastic layer, or a metal cored bar further provided with a release layer is widely used. As specific examples, the elasticity and non-staining property or non-adhesiveness of silicone rubber are used to form a single layer of silicone rubber on a cored bar, and silicone rubber compositions with different properties have different elasticity and releasability. Molded into a plurality of layers of an elastic layer and a release layer by sharing the function, it is often used especially for a fixing roller for a full-color image. Specifically, those in which an elastic layer is formed of HTV type (high temperature curing type) silicone rubber and a release layer is formed of RTV type (room temperature curing type) silicone rubber or LTV type (low temperature curing type) silicone rubber, etc. Are known. Further, since the elastic layer made of silicone rubber easily swells with the silicone oil applied to improve the releasability, an oil barrier layer made of fluororubber or fluororesin is provided between the elastic layer and the release layer. What is formed is also known.

A conventional fixing roller having a release layer made of silicone rubber as the outermost layer has a problem that the outer surface is swollen, so that the strength and wear resistance are deteriorated and the surface is easily scratched. On the other hand, in order to reinforce the outermost layer, a fixing roller having an outer surface formed of an RTV type silicone rubber mixed with an amorphous silicon dioxide having an average particle size of 1 to 20 μm as a filler (Japanese Patent Laid-Open No. 56-77874). JP-A-59-220347) and the like, in which a layer made of an addition type liquid silicone rubber containing dry fine silica powder and wet fine silica powder is formed.

However, since the silicone rubber containing the metal oxide particles such as silica is generally secondary agglomerated, the average particle size is actually 10 to 100 μm even when the particle size of the primary particles is small. As a result, the reinforcing effect was small, and the fixability was sometimes adversely affected. Further, there is a limit to uniformly and finely dispersing the inorganic filler such as metal oxide particles in the silicone rubber by mechanically kneading.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a fixing roller in which a layer made of silicone rubber is formed on a cored bar directly or via another layer, and the average particle size in the silicone rubber. The object of the present invention is to provide a fixing roller in which the strength is improved and the durability is improved by dispersing metal oxide particles having an extremely small value, without adversely affecting the fixing property, and a manufacturing method thereof.

The inventors of the present invention have conducted extensive studies to overcome the above-mentioned problems of the prior art. As a result, a composition in which a metal alkoxide is uniformly dispersed in a silicone rubber is used to form a silicone rubber layer or a silicone rubber. In the step of cross-linking, etc., by hydrolyzing and polycondensing a metal alkoxide in a silicone rubber by a sol-gel method,
It has been found that the metal oxide is generated as fine particles having an average particle size of 0.1 μm or less, and thereby the durability of the fixing roller can be improved without adversely affecting the fixing property. The present invention has been completed based on these findings.

[0008]

According to the present invention, in a fixing roller in which a silicone rubber layer containing metal oxide particles is formed on a core metal directly or through another layer, the metal oxide is used. The average particle diameter of the product particles is 0.1, which is generated by subjecting the metal alkoxide dispersed in silicone rubber to hydrolysis and polycondensation reaction by the sol-gel method.
There is provided a fixing roller characterized by being fine particles having a size of not more than μm. The fixing roller of the present invention is produced by the following methods A to D when producing a fixing roller in which a silicone rubber layer containing metal oxide particles is formed on a core metal directly or through another layer. can do.

The metal alkoxide is dispersed in the method A uncrosslinked silicone rubber, and the metal alkoxide is hydrolyzed and polycondensed by the sol-gel method to produce metal oxide particles having an average particle diameter of 0.1 μm or less. A method for producing a fixing roller, which comprises laminating an uncrosslinked silicone rubber containing the above directly or via another layer on the core metal, and crosslinking the silicone rubber.

The metal alkoxide is dispersed in the B-method uncrosslinked silicone rubber, the uncrosslinked silicone rubber in which the metal alkoxide is dispersed is laminated directly or through another layer, and the metal alkoxide is laminated by the sol-gel method. A method for producing a fixing roller, characterized in that a hydrolysis and polycondensation reaction is performed to generate metal oxide particles having an average particle size of 0.1 μm or less, and at the same time, a silicone rubber is crosslinked.

[0011] Method C : A metal alkoxide is dispersed in a non-crosslinked silicone rubber, the silicone rubber in which the metal alkoxide is dispersed is laminated directly or through another layer on the core metal, the silicone rubber is crosslinked, and the sol-gel method is used. A method for producing a fixing roller, wherein the metal alkoxide is hydrolyzed and polycondensed to produce metal oxide particles having an average particle diameter of 0.1 μm or less.

[0012] Method D non-crosslinked silicone rubber is laminated on a core metal directly or via another layer, the silicone rubber is crosslinked, the crosslinked silicone rubber is swollen to impregnate a metal alkoxide, and the metal is prepared by a sol-gel method. A method for producing a fixing roller, which comprises subjecting an alkoxide to hydrolysis and polycondensation to produce metal oxide particles having an average particle diameter of 0.1 μm or less.

Further, a preferred embodiment of the present invention is as follows. 1. The fixing roller, wherein the silicone rubber is RTV type silicone rubber or LTV type silicone rubber. 2. The fixing roller, wherein the silicone rubber has a vinyl group, a SiH group, or a hydroxyl group. 3. The silicone rubber is (A) at least one silicone rubber selected from the group consisting of a silicone rubber having a vinyl group, a silicone rubber having a SiH group, and a silicone rubber having a hydroxyl group, and (B) a fluorosilicone rubber, a phenyl silicone. The fixing roller, which is a mixture with at least one rubber selected from the group consisting of rubber and fluororubber.

4. The fixing roller, wherein the metal alkoxide is an alkoxide of at least one metal selected from the group consisting of silicon, titanium, aluminum, zirconium, and tungsten, and has at least two alkoxy groups. 5. The fixing roller, wherein a silicone rubber layer containing metal oxide particles is formed as an outermost layer. 6. The fixing roller, wherein a heat resistant elastic layer, an oil barrier layer, and a silicone rubber layer containing metal oxide particles are laminated in this order on a core metal. 7. The fixing roller, wherein a heat resistant elastic layer and a silicone rubber layer containing metal oxide particles are laminated in this order on a core metal.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The sol-gel method has been used for a long time, from a sol in which very fine colloid particles are dispersed in a solution, to a gel in which the solvent has evaporated and the dispersed particles have lost fluidity. This is known as a method for synthesizing ceramic powder or glass. By this sol-gel method, the hydrous oxide sol is dehydrated into a gel, and when the gel is heated, the inorganic oxide can be prepared in a certain shape.

This sol-gel method can be used as a method for dispersing an inorganic filler in crosslinked rubber.
Specifically, when a metal oxide such as silica is generated in situ in the network of crosslinked rubber, fine metal oxide particles are generated. Generally, in a method in which metal oxide particles such as silica are mechanically dispersed in unvulcanized rubber, the metal oxide particles cause secondary agglomeration to increase the particle size, and it is difficult to knead them uniformly. However, according to the sol-gel method, a state in which fine metal oxide particles are uniformly dispersed can be created. When rubber is reinforced with an inorganic filler, the smaller the particle size and the better the dispersion, the higher the reinforcing effect.

In the present invention, the metal alkoxide dispersed in the silicone rubber is hydrolyzed and polycondensed by the sol-gel method to produce a metal oxide as fine particles having an average particle size of 0.1 μm or less. Metal alkoxides form swollen gels when dispersed in silicone rubber with small amounts of water and catalysts. Next, when heat treatment is performed, a hydrolysis reaction and a polycondensation reaction proceed, and metal oxide particles are generated. For example, an alkoxysilane such as tetraethyl orthosilicate is dispersed in a silicone rubber together with water and a catalyst (eg, butylamine) to obtain 20 to 150.
When the heat treatment is performed at 3 ° C. for about 3 to 100 hours, silica, which is a metal oxide, is generated in the silicone rubber. Since the silicone rubber is crosslinked at any step in the production of the fixing roller, the produced silica is uniformly and finely dispersed in the network of the crosslinked silicone rubber. According to this method, metal oxide particles having an average particle size of 0.1 μm or less can be produced in silicone rubber.
When the metal oxide is generated in the silicone rubber by this sol-gel method, an excellent reinforcing effect can be obtained as compared with the case where silica prepared separately is kneaded.

As the metal alkoxide used in the present invention, one having at least 2, usually 4 to 6 alkoxy groups can be used. Typical metal alkoxides include silicon (Si), titanium (Ti),
Examples include alkoxides of aluminum (Al), zirconium (Zr), and tungsten (W). However, the present invention is not limited to these metal alkoxides. The metal alkoxide is silicone rubber 100
The amount is usually 0.5 to 100 parts by weight, preferably 1 to 50 parts by weight, and more preferably 5 to 20 parts by weight. If the mixing ratio of the metal alkoxide is too small, the reinforcing effect is small, and if it is too large, the fixability may be affected.

Along with the metal alkoxide, water is added in an amount ratio necessary for hydrolysis and a small amount of a catalyst for promoting polycondensation. The hydrolysis and polycondensation reactions are usually carried out by heat treating a silicone rubber containing a metal alkoxide. The heat treatment conditions are usually 20 to 150 ° C. and 3
˜100 hours, preferably 30 to 100 ° C. and about 5 to 80 hours.

As the method for forming the silicone rubber layer containing the metal oxide particles, the above-mentioned four methods A to D can be mentioned. For example, there is a method in which a metal alkoxide, water and a catalyst are put in the same container as the RTV type silicone rubber, heat treated under conditions that the RTV type rubber does not crosslink to generate metal oxide particles, and then molded and crosslinked. In this method, the crosslinking step or polycondensation step can be variously changed. Further, the molded and crosslinked product of silicone rubber is swollen by immersing it in a polar organic solvent such as tetrahydrofuran (THF), and then dipped in a mixed solution of metal alkoxide, water and a catalyst for impregnation, and then hydrolysis and polycondensation. There is a method of reacting. Among these methods, it is preferable to adopt the methods A to C in consideration of the fixing property.

As silicone rubber, HTV (high temperature curing type), LTV (low temperature curing type), RTV (room temperature curing type)
However, when the silicone rubber layer is used as the release layer, RTV type or LTV type silicone rubber is preferable. When a silicone rubber having a vinyl group, a SiH group, a hydroxyl group, or the like is used, after the metal alkoxide is hydrolyzed, it reacts with these functional groups as it undergoes polycondensation, and the fine particles chemically react with the silicone rubber. Because of the bonding, an excellent reinforcing effect can be expected.

As the silicone rubber, at least one silicone rubber selected from the group consisting of (A) a silicone rubber having a vinyl group, a silicone rubber having a SiH group, and a silicone rubber having a hydroxyl group, and (B) a fluorosilicone. It is possible to use a mixture with at least one rubber selected from the group consisting of rubber, phenyl silicone rubber, and fluororubber. When used in combination with the rubber of the group (B), oil resistance and heat resistance can be improved. The usage ratio (A: B weight ratio) of the silicone rubber of the (A) group and the rubber of the (B) group can be appropriately determined in consideration of the balance between the releasability and the oil resistance and heat resistance. However, it is usually 5:95 to 90:10, preferably 30: 7.
It is 0 to 70:30. The silicone rubber layer can be formed directly on the metal cored bar or via a primer. Alternatively, an elastic layer made of rubber may be formed and then a silicone rubber layer may be formed thereon. Furthermore, an elastic layer made of rubber, an oil barrier layer, and a silicone rubber layer may be sequentially formed.

From the viewpoint of heat resistance, silicone rubber, fluororubber, or a mixture thereof is preferably used as the material of the elastic layer used in the present invention. The type of the silicone rubber may be any of a millable type and a liquid type, and may be any of HTV (high temperature curing type), LTV (low temperature curing type), and RTV (room temperature curing type). The chemical structure of the silicone rubber may be any of basic dimethyl silicone rubber; silicone rubber having vinyl group, hydrogen group, hydroxyl group, etc .; phenyl silicone rubber; fluorosilicone rubber, and two or more of them. It may be any mixture. The thickness of the elastic layer is appropriately set in consideration of the application, the structure of the mechanical device to be installed, the target elasticity, the hardness of the material used, etc., but is generally 10
It is often set within the range of 0 μm to 3 mm. Of course, after forming into a thicker film, it may be processed to a required film thickness by polishing or the like. The elastic layer may be laminated on the core metal via a primer, and the core metal may be roughened by blasting, electrochemical etching, chemical etching, or a combination thereof, and further, if necessary. May be laminated via a primer.

The oil barrier layer is a layer having a role of preventing the silicone oil, which is applied to the fixing roller and used for improving the releasability, from penetrating into the elastic layer, and is usually oil resistant. It is formed using excellent fluororubber or fluororesin. This layer is usually 5-100 μm
Degree is fine. However, it is not limited to this range. The silicone rubber layer in which the metal oxide is dispersed is usually disposed as the outermost layer and functions as a release layer. The thickness of the silicone rubber layer as a release layer is usually about 5 to 500 μm. However, it is not limited to this range.

[0025]

The present invention will be described in more detail with reference to the following examples and comparative examples, but the present invention is not limited to these examples.

[Example 1] A weight ratio of HTV dimethyl silicone rubber (KE931U manufactured by Shin-Etsu Chemical Co., Ltd.) and fluorosilicone rubber (FE241U manufactured by Shin-Etsu Chemical Co., Ltd.) was set on a core metal made of aluminum having an outer diameter of 56 mm at a weight ratio of 1: 1. 100 parts by weight of the rubber blended with
-8A (manufactured by Shin-Etsu Chemical Co., Ltd.) was kneaded in an amount of 0.5 part by weight to give about 3 parts.
A sheet having a thickness of mm was wound around and press-vulcanized with a mold to form an elastic layer as an inner layer. On the other hand, uncrosslinked R
TV type dimethyl silicone rubber (KE19 manufactured by Shin-Etsu Chemical Co., Ltd.
35) 100 parts by weight of tetraethyl orthosilicate, 50 parts by weight, 1 part by weight of water, and 0.5 parts by weight of butylamine as a catalyst were mixed, and heat treated at 70 ° C. for 24 hours to react with metal alkoxide. The metal oxide, silica, was formed in the rubber. Then, the produced silica-containing dimethyl silicone rubber is applied on the elastic layer previously formed, and heat-treated at 120 ° C. for 1 hour to cross-link it.
A release layer having a thickness of 00 μm was formed to complete the fixing roller (FIG. 1). According to the result of observation with an electron microscope, the average particle size of the produced silica was 0.1 μm or less.

[Comparative Example 1] As a comparative example, a release layer having the same structure as that of Example but containing no generated silica was produced. Durability Test When the manufactured roller was evaluated by a rotation durability test apparatus simulating actual fixing as shown in FIG. 2, the comparative sample (Comparative Example 1) had streaky scratches on the surface after 500 hours. On the other hand, in the product of the present invention (Example 1), no scratches were generated even after 1000 hours. Further, as a result of subsequently incorporating these into an actual machine and performing a drawing test, the product of the present invention was in a state in which there were not many streaks and the like, and there was no problem. In the comparative sample, color unevenness was clearly observed and streaks were conspicuous.

[0028]

According to the present invention, in a fixing roller in which a layer made of silicone rubber is formed on a core metal directly or via another layer, a metal having an extremely small average particle diameter is contained in the silicone rubber. Dispersing the oxide particles provides a fixing roller having improved strength and improved durability without adversely affecting the fixing property, and a manufacturing method thereof.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a structure of a fixing roller prepared in an example.

FIG. 2 is a schematic diagram showing the structure of a rotation durability tester.

[Explanation of symbols]

1: Core metal 2: HTV type silicone rubber layer (elastic layer) 3: RTV dimethyl silicone layer (release layer containing silica produced) 4: Web 5: Fixing roller 6: Pressure roller

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location F16C 13/00 9037-3J F16C 13/00 A (72) Inventor Toshihiko Takiguchi Osaka, Konohana-ku, Osaka 1-3-1 Shimaya Sumitomo Electric Industries, Ltd. Osaka Works (72) Inventor Akira Nishimura 1-3-3 Shimaya, Konohana-ku, Osaka City, Osaka Sumitomo Electric Industries Ltd.

Claims (7)

[Claims] 1. A fixing roller in which a silicone rubber layer containing metal oxide particles is formed directly or through another layer on a core metal, the metal oxide particles being dispersed in the silicone rubber. A fixing roller comprising fine particles having an average particle diameter of 0.1 μm or less produced by subjecting the metal alkoxide to hydrolysis and polycondensation reaction by a sol-gel method. 2. The silicone rubber comprises at least one silicone rubber selected from the group consisting of (A) a silicone rubber having a vinyl group, a silicone rubber having a SiH group, and a silicone rubber having a hydroxyl group, and (B) a fluoro rubber. The fixing roller according to claim 1, which is a mixture with at least one rubber selected from the group consisting of silicone rubber, phenyl silicone rubber, and fluororubber. 3. The metal alkoxide is silicon, titanium,
The fixing roller according to claim 1, which is an alkoxide of at least one metal selected from the group consisting of aluminum, zirconium, and tungsten, and which has at least two alkoxy groups. 4. A method for producing a fixing roller, comprising forming a silicone rubber layer containing metal oxide particles on a core metal directly or via another layer, wherein a metal alkoxide is dispersed in an uncrosslinked silicone rubber, The metal alkoxide is hydrolyzed and polycondensed by the sol-gel method to produce metal oxide particles having an average particle size of 0.1 μm or less, and the uncrosslinked silicone rubber containing the metal oxide particles is directly or on another core metal. A method for producing a fixing roller, comprising laminating via layers, and crosslinking a silicone rubber. 5. A method for producing a fixing roller, which comprises forming a silicone rubber layer containing metal oxide particles on a core metal directly or through another layer, wherein a metal alkoxide is dispersed in an uncrosslinked silicone rubber, An uncrosslinked silicone rubber in which a metal alkoxide is dispersed is laminated directly on a core metal or through another layer, and the metal alkoxide is hydrolyzed and polycondensed by a sol-gel method to obtain an average particle size of 0.1 μm or less. A method for producing a fixing roller, characterized in that a metal oxide particle is generated and at the same time, a silicone rubber is crosslinked. 6. A method for producing a fixing roller, comprising forming a silicone rubber layer containing metal oxide particles directly or through another layer on a core metal, wherein a metal alkoxide is dispersed in an uncrosslinked silicone rubber, The silicone rubber in which the metal alkoxide is dispersed is laminated on the core metal directly or through another layer to crosslink the silicone rubber, and the metal alkoxide is hydrolyzed and polycondensed by the sol-gel method to obtain an average particle size of 0. A method for producing a fixing roller, which comprises producing metal oxide particles of 1 μm or less. 7. A method for producing a fixing roller, comprising forming a silicone rubber layer containing metal oxide particles on a core metal directly or via another layer, wherein an uncrosslinked silicone rubber is directly or directly on the core metal. Laminate through other layers, crosslink silicone rubber, swell crosslinked silicone rubber to impregnate metal alkoxide, and hydrolyze and polycondense metal alkoxide by sol-gel method to obtain average particle size 0.1 μm A method for producing a fixing roller, comprising producing the following metal oxide particles.