JP2903972B2 - Fixing belt - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing belt used in an image forming apparatus such as an electrophotographic copying machine, a facsimile, and a printer.

[0002]

2. Description of the Related Art
As a fixing belt used in an image forming apparatus, a belt made of a fluororesin film and a belt obtained by applying a silicone rubber composition to the surface of a heat-resistant resin film and curing by heating (Japanese Patent Application Laid-Open No. 4-115279).
Etc. are known.

However, since the fixing belt made of fluororesin is very hard, when this belt is used for fixing in an image forming apparatus, its surface cannot follow fine irregularities. When the image is fixed on the recording paper by heating and pressurizing, the image transferred on the recording paper is reversely transferred to the belt, so that there is a problem that the image quality is deteriorated.

When a heat-resistant resin film having a silicone rubber layer formed on its surface is used as a fixing belt, a small amount of silicone oil contained in the silicone rubber improves toner releasability, but causes bleeding. Since the amount of oil is limited, the releasability changes with time, so it is difficult to completely suppress the reverse transfer of the image from the recording paper to the fixing belt without supplying the silicone oil. . In addition, particularly in a color image forming apparatus such as a color copying machine, supply of silicone oil is indispensable at present, and therefore, a belt having an outermost layer formed of silicone rubber which is greatly swelled by silicone oil is used for color image forming. There is a problem in using it for fixing the apparatus.

[0005] The present invention has been made in view of the above circumstances,
An object of the present invention is to provide a fixing belt that exhibits toner release properties equal to or higher than that of silicone rubber, has a small swelling due to silicone oil, and can obtain high-quality images.

[0006]

The present inventors have conducted intensive studies to achieve the above object, and as a result, have formed an image forming apparatus in which a fluorocarbon siloxane rubber layer is formed on the outer surface of a tubular belt body. It has been found that when used as a fixing belt, the toner exhibits a toner releasability equal to or higher than that of silicone rubber, has a small swelling due to silicone oil, and can provide a high-quality image. Further, in this case, a fluorocarbon siloxane rubber having a perfluoroalkyl ether group and / or a perfluoroalkyl group in the main chain has a high effect, and in particular, a cured product of the following fluorocarbon siloxane rubber composition has a high effect. Thus, the present invention has been accomplished. Fluo
A locarbon siloxane rubber composition (A) comprising a fluorocarbon siloxane having a repeating unit represented by the following general formula (1) as a main component, and a fluorocarbon polymer having an aliphatic unsaturated group;

[0007]

Embedded image Wherein R ¹⁰ is an unsubstituted or substituted monovalent hydrocarbon group, x
Is an integer of 1 or more, a and e are each 0 or 1, b and d are each an integer of 1 to 4, and c is an integer of 0 to 8. (B) Two or more ≡SiH groups are contained in one molecule, and the content of the ≡SiH group is 1 to 4 times the molar amount of the aliphatic unsaturated group in the fluorocarbon siloxane rubber composition. An organopolysiloxane and / or a fluorocarbon siloxane, (C) a filler, and (D) an effective amount of a catalyst.

Hereinafter, the present invention will be described in more detail. As described above, the fixing belt of the present invention is formed by forming a fluorocarbon siloxane rubber layer on the outer surface of a tubular belt body.

Here, the tubular belt body may be formed of a heat-resistant resin usable at 150 to 180 ° C., such as a polyimide resin, a fluorine resin, or a polyester resin, or a metal such as stainless steel or nickel. it can. The thickness of the heat-resistant resin belt and the metal belt body is not particularly limited, but is preferably 20 to 300 μm, particularly preferably 40 to 100 μm from the viewpoint of heat conductivity and heat resistance.

In the present invention, the fluorocarbon siloxane rubber forming the fluorocarbon siloxane rubber layer formed on the belt body preferably has a perfluoroalkyl ether group and / or a perfluoroalkyl group in the main chain. Particularly, the fluorocarbon siloxane rubber includes (A) a fluorocarbon siloxane having a fluorocarbon siloxane represented by the following general formula (1) as a main component and an aliphatic unsaturated group, and (B) two or more ≡SiH / molecules. An organopolysiloxane and / or a fluorocarbon siloxane containing a group, wherein the content of the ≡SiH group is from 1 to 4 times the molar amount of the aliphatic unsaturated group in the fluorocarbon siloxane rubber composition, (C) It is preferably a cured product of a fluorocarbon siloxane rubber composition containing a filler and (D) an effective amount of a catalyst.

In this case, the fluorocarbon polymer as the component (A) contains a fluorocarbon siloxane having a repeating unit represented by the following general formula (1) as a main component and has an aliphatic unsaturated group. This aliphatic unsaturated group is a monovalent aliphatic unsaturated hydrocarbon group, preferably having 2 to 3 carbon atoms, specifically, a vinyl group, an allyl group,
An alkenyl group having 2 to 3 carbon atoms such as an ethynyl group is exemplified, and a vinyl group is particularly preferable. In this case, the aliphatic unsaturated group is preferably at the terminal of the molecular chain, and for example, preferably has a vinyldialkylsilyl group, divinylalkylsilyl group or trivinylsilyl group in the main chain. In addition,
In this case, the alkyl group preferably has 1 to 8 carbon atoms, particularly a methyl group.

[0012]

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In the above formula (1), R ¹⁰ is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 8 carbon atoms, preferably an alkyl group having 1 to 8 carbon atoms or a carbon atom having 1 to 8 carbon atoms. It is 2-3 alkenyl groups, particularly preferably a methyl group. a and e are each 0 or 1, b and d are each an integer of 1 to 4, and c is an integer of 0 to 8. X is an integer of 1 or more, preferably 10 to 30.

As the component (A), those represented by the following formula (2) can be exemplified.

[0015]

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The component (B) contains two or more ΔS in one molecule.
Organopolysiloxanes and / or fluorocarbons containing iH groups, wherein the ≡SiH groups are 1 to 4 times the molar amount of the aliphatic unsaturated groups in the fluorocarbon siloxane composition.

Here, the organopolysiloxane having a ≡SiH group includes an organohydrogenpolysiloxane having at least two hydrogen atoms bonded to silicon atoms in a molecule.

In the fluorocarbon siloxane rubber composition used in the present invention, when the fluorocarbon polymer as the component (A) has an aliphatic unsaturated group, the above-mentioned organohydrogenpolysiloxane is used as a curing agent. be able to. That is, in this case, a cured product is formed by an addition reaction occurring between an aliphatic unsaturated group in the fluorocarbon siloxane and a hydrogen atom bonded to a silicon atom in the organohydrogenpolysiloxane.

As such an organohydrogenpolysiloxane, various organohydrogenpolysiloxanes used in an addition-curable silicone rubber composition can be used. In the present invention, the following are particularly preferable. It is preferably used.

(1) an organohydrogenpolysiloxane represented by the following formulas (3) to (5):

[0021]

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In the above formula, s and t are integers of 0 or more, and u is an integer of 2 or more. R ² is an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, and preferably has 1 to 12, more preferably 1 to 8 carbon atoms. Group, ethyl group, isopropyl group,
Alkyl groups such as butyl group, cycloalkyl groups such as cyclohexyl group and cyclopentyl group, aryl groups such as phenyl group, tolyl group and xylyl group, aralkyl groups such as benzyl group and phenylethyl group, chloromethyl group, chloropropyl group, Examples thereof include halogenated hydrocarbon groups such as chlorocyclohexyl group and 3,3,3-trifluoropropyl group, and cyano hydrocarbon groups such as 2-cyanoethyl group. Among them, particularly preferred are a methyl group, an ethyl group, a phenyl group and a 3,3,3-trifluoropropyl group. R
⁴ is a divalent group interposed between the silicon atom and the fluorinated organic group R _f, and is a divalent hydrocarbon group having no aliphatic unsaturated bond or a general formula -R ⁵ -OR ^6- (However, R ⁵ and R ⁶
Is a divalent hydrocarbon group having no aliphatic unsaturated bond), and has a ether group, and preferably has 1 to 8 carbon atoms. Specific examples include the following.

[0023]

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A particularly preferred group among R ⁴ is —C
_{H 2 CH 2 -, - CH} 2 CH 2 CH 2 -, - CH 2 CH 2 CH 2
—O—CH ₂ —. R _f is a perfluoroalkyl group or a perfluoroalkyl ether group. As the perfluoroalkyl group, a compound represented by the formula C _p F _{2p + 1} (where p is 4 to 1)
And an especially preferred group is C ₆ F ₁₃ —, C ₈ F ₁₇ —, or C ₁₀ F ₂₁ —. As the perfluoroalkyl ether group, the carbon number is particularly 5 to 5.
Fifteen are preferred, and the following are specifically exemplified.

[0025]

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(2) _0.5 unit of (CH ₃ ) ₂ HSiO and Si
A copolymer comprising O ₂ units.

[0027]

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The viscosity of these organohydrogenpolysiloxanes at 25.degree.
It is preferably 0 cSt or less.

The above-mentioned organohydrogenpolysiloxane generally has at least one ≡SiH group, preferably one to one aliphatic unsaturated hydrocarbon group in the fluorocarbon siloxane of the component (A). It is preferable to mix them in such a ratio that the number becomes five.

Further, as the fluorocarbon having a ≡SiH group, the unit of the above formula (1) or R ¹⁰ in the formula (1) is a dialkyl hydrogensiloxy group and the terminal is a dialkyl hydrogen siloxy group or a silyl group. Is preferably a SiH group represented by the following formula (7):
Can be mentioned.

[0031]

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As the filler of the component (C), various fillers used in general silicone rubber compositions can be used. For example, fumed silica, precipitated silica, carbon powder, titanium dioxide, aluminum oxide,
Examples thereof include reinforcing powders such as quartz powder, talc, sericite and bentonite, and fibrous fillers such as asbestos, glass fiber and organic fiber.

These fillers are used in an amount of 10 to 300 parts, especially 2 parts, per 100 parts of the component (A) (parts by weight, the same applies hereinafter).
It is preferable to mix in a ratio of 0 to 200 parts. When the amount of the filler is less than 10 parts, a sufficient reinforcing effect cannot be obtained, and when the amount is more than 300 parts, the mechanical strength of the cured product decreases. This may cause inconvenience.

As the catalyst of the component (D), chloroplatinic acid, alcohol-modified chloroplatinic acid, a complex of chloroplatinic acid and an olefin, platinum black or palladium converted to alumina, silica, Group VIII elements of the periodic table such as those supported on a carrier such as carbon, a complex of rhodium and an olefin, chlorotris (triphenylphosphine) rhodium (Wilkinson's catalyst), rhodium (III) acetylacetonate, or a compound thereof However, these complexes are preferably used after being dissolved in a solvent such as an alcohol, an ether or a hydrocarbon.

The amount of the platinum group metal-based catalyst may be any as long as it is an effective amount of the catalyst. Usually, the amount of the platinum group metal-based catalyst is 1 to 500 ppm, especially 5 to 500 parts per 100 parts of the component (A).
Preferably, it is used at a rate of ２０20 ppm.

In the fluorocarbon siloxane rubber composition used in the present invention, various additives can be added as long as the object of the present invention of improving solvent resistance is not impaired. For example, dispersants such as diphenylsilane diol, dimethylpolysiloxane having a low degree of polymerization and a hydroxyl group blocked at the molecular chain end, and hexamethyldisilazane; heat-resistance improvers such as ferrous oxide, ferric oxide, cerium oxide, and iron octylate And a colorant such as a pigment can be added as necessary.

The fixing belt of the present invention can be obtained by coating the outer surface of a heat-resistant resin or metal tubular belt body with the above fluorocarbon siloxane rubber composition and curing by heating. It can be diluted with a solvent such as m-xylene hexafluoride, benzotrifluoride or the like to obtain a coating solution, which can be applied by a general coating method such as spray coating, dip coating and knife coating. In addition, the temperature and time for heat curing can be appropriately selected, and are usually selected from the range of 100 to 500 ° C. and the time of 5 seconds to 5 hours depending on the type of the tube main body and the manufacturing method.

The thickness of the rubber layer formed on the outer surface of the belt body is not particularly limited, but is preferably from 20 to 500 μm, particularly from 40 to 200 μm in order to obtain good fixability of the image.
m is preferable.

[0039]

EXAMPLES The present invention will be described below in detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

Example 1 A fluorocarbon siloxane 1 represented by the following formula (8)
00 parts, 3.87 parts of a curing agent represented by the following formula (9), 1.0 part of a 1% by weight toluene solution of tris (triphenylphosphine) rhodium (I) chloride as a catalyst, and a treatment with a trimethylsiloxy group as a reinforcing agent. 12 parts of the fumed silica filler thus obtained were mixed to obtain a fluorocarbon siloxane rubber composition I.

[0041]

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Next, the outer surface of a nickel tubular fixing belt body having an axial length of 300 mm, an inner diameter of 200 mm, and a thickness of 0.05 mm was washed with methyl alcohol, and a tetrabutyl titanate polymer (primer) was used as a primer. A 5% by weight solution of TBT-1000 (B-10), manufactured by Nippon Soda Co., Ltd.) in 4-methyl-2-pentanone was applied and air-dried for 30 minutes. Next, a 20% by weight benzotrifluoride solution of the composition I was applied to the outer surface of the belt by a dipping method, air-dried for 30 minutes, and then heated and cured at 150 ° C. for 1 hour. As a result, a fixing belt was obtained in which the composition I had a thickness of 0.05 mm and was well adhered and applied to the outer surface of the nickel belt.

A toner releasability test was performed on the obtained fixing belt. That is, as shown in FIG. 1, a toner layer 2 having a thickness of about 100 μm is provided on PPC paper (manufactured by Ricoh, type 6200) 1 and a fixing belt 3 (4 is a rubber layer, Place the belt body) on the paper on which the toner is placed, and apply a heating and pressing device (heat seal tester /
7P-701-B, manufactured by Tester Sangyo Co., Ltd.) 6
Temperature 180-200 ° C, pressure 2.0-4.0 kg / cm
^This was performed by heating and pressing at ² for 1 second and observing the state of separation between the fixing belt and the paper. As a result, the fixing belt to which the composition I was applied was excellent in peeling from the paper, and no toner was adhered to the belt.

In the test for silicone oil resistance, silicone oil (KC-96 (100 cS
t), manufactured by Shin-Etsu Chemical Co., Ltd.
Vulcanized rubber physical test method (JISK-630)
An immersion test according to 1) was performed. As a result, the weight increase rate was 2.8%, the volume increase rate was 3.2%, and the oil swelling was small.

From the above results, it was confirmed that this fixing belt exhibited excellent toner release properties and silicone oil resistance, and was extremely useful as a fixing belt.

Comparative Example 1 100 parts of a silicone oil having a viscosity of 10,000 cSt represented by the following formula (10), 1.4 parts of a curing agent having a viscosity of 12 cSt represented by the following formula (11), and chloroplatinic acid as a catalyst 0.4 part of a 2% by weight alcohol solution, fumed silica filler 2 treated with trimethylsiloxy group as a reinforcing agent
0 parts were mixed to obtain a silicone rubber composition II.

[0047]

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Next, the belt body was subjected to a primer treatment in the same manner as in Example 1 to obtain a 15% by weight of the composition II.
The heptane solution was applied by a dipping method, air-dried for 30 minutes, and then heat-cured at 150 ° C. for 1 hour. As a result, a fixing belt was obtained in which the composition II had a thickness of 0.08 mm and was well adhered and applied to the outer surface of the nickel belt main body.

Example 1 of the obtained fixing belt
As a result of a toner releasability test conducted in the same manner as in the above, it was found that the fixing belt had good peeling from paper and no toner adhered to the belt. However, as a result of performing a test for silicone oil resistance in the same manner as in Example 1,
The weight increase was 19.3% and the volume increase was 27.3%, and the oil swelling was very large.

[0050]

As described above, the fixing belt of the present invention exhibits toner releasability equal to or higher than that of silicone rubber, has a small swelling due to silicone oil, and can provide high quality images.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram for explaining a toner releasability test in Examples and Comparative Examples of the present invention.

[Explanation of symbols]

 Reference Signs List 1 PPC paper 2 Toner layer 3 Fixing belt 4 Rubber layer 5 Belt body 6 Heating and pressing device

──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Hiroshi Takei 1-10 Hitomi, Matsuida-machi, Usui-gun, Gunma Prefecture Inside Silicone Electronics Materials Research Laboratory Shin-Etsu Chemical Co., Ltd. (72) Inventor Takeshi Hashimoto Matsui, Usui-gun, Gunma Prefecture Hitomi Tamachi 1-10 Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory (56) References JP-A-4-115279 (JP, A) JP-A-3-214183 (JP, A) JP-A-2 -25882 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) G03G 13/20 G03G 15/20

Claims (3)

(57) [Claims] 1. A fixing belt comprising a tubular belt main body and a fluorocarbon siloxane rubber layer formed on an outer surface thereof. 2. The method according to claim 1, wherein the fluorocarbon siloxane rubber has a perfluoroalkyl ether group and / or a perfluoroalkyl group in the main chain.
The fixing belt as described in the above. 3. The fixing belt according to claim 1, wherein the fluorocarbon siloxane rubber is a cured product of a fluorocarbon siloxane rubber composition having the following components (A) to (D). (A) a fluorocarbon polymer containing a fluorocarbon siloxane having a repeating unit represented by the following general formula (1) as a main component and having an aliphatic unsaturated group: Wherein R ¹⁰ is an unsubstituted or substituted monovalent hydrocarbon group, x
Is an integer of 1 or more, a and e are each 0 or 1, b and d are each an integer of 1 to 4, and c is an integer of 0 to 8. (B) Two or more ≡SiH groups are contained in one molecule, and the content of the ≡SiH group is 1 to 4 times the molar amount of the aliphatic unsaturated group in the fluorocarbon siloxane rubber composition. An organopolysiloxane and / or a fluorocarbon siloxane, (C) a filler, and (D) an effective amount of a catalyst.