JPH0122483B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a heat generating roll, and more particularly to a heat generating roll having an inner insulating layer, a heat generating layer, and an outer insulating layer provided on the roll body, if necessary. Conventionally, heat generating rolls have a heating element inside the roll,
For example, those that incorporate heating wires are used. However, this type of heating roll has disadvantages such as considerable heat loss, and when the internal heating element wears out or breaks, the roll must be stopped and repaired. Therefore, there is a strong demand for a heat generating roll with low heat loss and long life. On the other hand, in dry electrostatic printing, the toner image formed on the printing material is finally fused and fixed to the printing material by a fixing roll to obtain a printed material. As the roll, an elastic roll having a heat-resistant rubber layer such as fluorocarbon rubber or silicone rubber on the outer peripheral surface of a metal roll body is used. However, with this type of roll, the fused toner tends to adhere to the roll, making the printed image unclear, so a fixing roll with good releasability for the fused toner is required. In order to meet such requirements, polytetrafluoroethylene (hereinafter referred to as
Abbreviated as "PTFE". ) layer, and a fixing roll in which a PTFE layer is further provided on the outer peripheral surface of a metal roll with the rubber layer interposed therebetween. Although these fixing rolls are fully satisfactory in terms of releasability of the fused toner,
Since the former roll has little elasticity, it has poor feeding performance of the printing material, and pressure is applied unevenly, resulting in local wear of the roll surface. Additionally, due to the inherent non-adhesive properties of PTFE, the PTFE layer easily peels off from the roll body. In the latter fixing roll, in addition to the inherent non-adhesiveness of PTFE, the rubber layer and PTFE layer are separated due to the generation of volatile matter from the rubber layer due to the high temperature (328°C or higher) when PTFE is bonded to the rubber layer. The rubber layer and
Peeling from the PTFE layer is likely to occur. The inventors have sufficient non-stick properties on the surface,
As a result of repeated research to develop a heat-generating roll that eliminates the drawbacks of the conventional technology, it was found that an excellent heat-generating roll can be created by providing a heat-generating layer on the outer circumferential surface of an insulating roll and coating and insulating the top with non-adhesive paint. The inventors have discovered that the present invention can be obtained and completed the present invention. The gist of the present invention resides in a heat generating roll characterized in that an inner insulating layer, a heat generating layer and an outer insulating layer are provided on the outer peripheral surface of the roll, if necessary. In the heating roll of the present invention, fluorocarbon rubber, silicone rubber, fluorocarbon resin, silicone resin, etc. can be used as the outer insulating layer, and fluorocarbon rubber is particularly preferred. Among fluororubbers, it includes fluororubbers, coupling agents and liquid carriers,
A fluororubber coating film obtained by applying and curing a fluororubber coating containing an amine compound and/or an inorganic fibrous substance if necessary is preferred. Furthermore, if a fluororesin is added to this fluororubber paint, the surface of the resulting coating film will be made non-adhesive, and fixing rolls in electrostatic printing will be prevented from adhering toner, and rolling rolls will be able to prevent toner from adhering to the rolled object. This is more preferable since fusion can be prevented. As the heat generating layer, a coating film obtained by applying and curing a conductive paint is used. Examples of the conductive paint include fluorocarbon rubber, silicone rubber, fluorocarbon resin, silicone resin, polyimide resin, and polyamideimide resin containing a conductive substance. Among these, conductive fluororubber paints containing fluororubber, a coupling agent, a conductive substance, a liquid carrier, and optionally an amine compound and/or an inorganic fibrous substance are preferred. For the inner insulating layer provided if necessary, ordinary heat-resistant rubber or resin such as fluorocarbon rubber, silicone rubber, silicone resin, polyimide resin, polyamideimide resin, etc. is used. Moreover, an inorganic insulating material can also be used. The fluororubber contained in the fluororubber paint and the conductive fluororubber paint used in the present invention as the paint for the outer insulating layer is a highly fluorinated copolymer with a particularly preferred property. Examples of the fluororubber include usually elastic copolymers of 40 to 85 mol% vinylidene fluoride and at least one other fluorine-containing ethylenically unsaturated monomer that can be copolymerized with vinylidene fluoride. Further, as the fluororubber, a fluororubber containing an iodine chain in the polymer chain is also preferably used. This iodine-containing fluororubber has, for example, 0.001 to 10% by weight, preferably 0.01 to 5% by weight of iodine bonded to the end of the polymer chain, and is the same as above.
Fluororubber (specially (See No. 40543, 1973). Other fluorine-containing ethylenically unsaturated monomers that can be copolymerized with vinylidene fluoride to give elastic copolymers include hexafluoropropylene, pentafluoropropylene, trifluoroethylene, trifluorochloroethylene,
Tetrafluoroethylene, vinyl fluoride,
Representative examples include perfluoro(methyl vinyl ether), perfluoro(ethyl vinyl ether), and perfluoro(propyl vinyl ether). Particularly desirable fluororubbers are vinylidene fluoride/hexafluoropropylene dielastic copolymers and vinylidene fluoride/tetrafluoroethylene/hexafluoropropylene terelastic copolymers. The coupling agent contained in both of these fluororubber paints acts on the interface between organic and inorganic materials,
A compound that forms a strong bridge between two materials through chemical or physical bonding, and is usually a compound of silicon, titanium, zirconium, hafnium, thorium, tin, aluminum, or magnesium, and is used to bond organic and inorganic materials. It is a compound that has a group capable of bonding. Among these coupling agents, preferred are silane coupling agents and orthoacid esters of Group transition elements of the periodic table (such as titanium or zirconium) and derivatives thereof, with aminosilane compounds being most preferred. Examples of the silane coupling agent include the general formula: R ¹・Si ・R ² _3-a・R ³ _a [wherein R ¹ is a chlorine atom, an amino group, an aminoalkyl group, a ureido group, a glycidoxy group, an epoxycyclohexyl group] , an alkyl group having 1 to 10 carbon atoms or a vinyl group having at least one functional atom or group selected from acrylicyloxy group, methacryloyloxy group, mercapto group, and vinyl group, R ² and R ³ are each chlorine atoms, hydroxyl groups,
An atom or group selected from an alkoxy group having 1 to 10 carbon atoms, an alkoxy-substituted alkoxy group having 2 to 15 carbon atoms, a hydroxyalkyloxy group having 2 to 4 carbon atoms, and an acyloxy group having 2 to 15 carbon atoms, a is 0 , 1 or 2. ] Examples include silane compounds represented by the following. R ¹ is an alkyl group having a functional substituent, and preferable examples thereof include β-aminoethyl group, γ-aminopropyl group, N-(β-aminoethyl)-γ-aminopropyl group. , γ-ureidopropyl group, γ-glycidoxypropyl group, β-
(3,4-epoxycyclohexyl)ethyl group,
Examples include γ-acryloyloxypropyl group, γ-methacryloyloxypropyl group, γ-mercaptopropyl group, β-chloroethyl group, γ-chloropropyl group, and γ-vinylpropyl group.
Further, R ¹ may be a vinyl group. Specific examples of the silane compounds preferably used include γ-aminopropyltriethoxysilane, N-β-aminoethyl-γ-aminopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, and γ-glycidoxypropyl. Trimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethylsilane, γ-methacryloxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, vinyltris(β-methoxyethoxy) Silane, vinyltriethoxysilane, vinyltrichlorosilane, vinyltriacetoxysilane, N-(trimethoxysilylpropyl)ethylenediamine, N-β-aminoethyl-γ-aminopropylmethyldimethoxysilane, β-aminoethyl-β-aminoethyl −γ
-aminopropyltrimethoxysilane and the like. Among these silane coupling agents, aminosilane compounds such as γ-aminopropyltriethoxysilane (hereinafter referred to as A-1100), N-β-aminoethyl-γ-aminopropyltrimethoxysilane, N-(trimethoxysilylpropyl) Ethylenediamine, N-β-aminoethyl-γ-aminopropylmethyldimethoxysilane, γ-ureidopropyltriethoxysilane, β-aminoethyl-β-aminoethyl-γ-
Compounds such as aminopropyltrimethoxysilane not only function as vulcanizing agents for fluorocarbon rubber, but also greatly contribute to improving adhesion to substrates, and are also safe to use with liquid carriers, so they are especially useful. preferable. Examples of compounds of titanium, zirconium, hafnium and thorium include the general formula: T(OR) ₄ [wherein T represents titanium, zirconium, hafnium or thorium, and R represents an alkyl group, a cycloalkyl group or an aryl group. ] Examples include derivatives obtained by reacting an orthoacid ester represented by the following and one or more compounds having at least one functional group therewith. Examples of the above-mentioned compounds having at least one functional group include glycerin, ethylene glycol, 1,
3-butanediol, 2,3-butanediol,
Polyhydric alcohols such as hexylene glycol and octylene glycol, oxyaldehydes such as salicylaldehyde and glucose, oxyketones such as diacetone alcohol and fructose, glycolic acid, lactic acid, dioxymaleic acid,
Oxycarboxylic acids such as citric acid, diketonic acids such as diacetylacetone, ketonic acids such as acetoacetic acid, esters of ketonic acids such as ethyl acetoacetate, oxyamines such as triethanolamine and diethanolamine, oxyphenols such as catechol and pyrogallol. Compounds etc. can be used. Examples of specific compounds when T is titanium include tetraalkyl titanate (e.g., tetraethyl titanate, tetraisopropyl titanate, tetrabutyl titanate), tetraethylene glycol titanate, triethanolamine titanate, titanium acetylacetonate. , isopropyl trioctanoyl titanate, isopropyl trimethacryl titanate, isopropyl triacryl titanate, isopropyl tri(butyl, methyl pyrophosphate) titanate, tetraisopropyl di(dilauryl phosphite) titanate,
Examples include dimethacryloxyacetate titanate, diacryloxyacetate titanate, di(dioctyl phosphate) ethylene titanate, and the like. As the zirconium compound, a compound similar to the above titanium compound can be used. Specific examples include tetraalkyl zirconates such as tetraethyl zirconate and tetrabutyl zirconate, n-propyl zirconate, isopropyl zirconate, n-butyl zirconate, isobutyl zirconate, zirconium acetylacetonate, and the like. As the hafnium and thorium compounds, compounds similar to titanium and zirconium can be used. As the tin compound, an organic or inorganic compound such as SnCl ₄ can be used. Examples of aluminum compounds include aluminum isopropylate, monosec-butoxyaluminum diisopropylate, aluminum sec-butyrate, ethyl acetoacetate aluminum diisopropylate, and aluminum tris (ethylacetoacetate). Examples of the magnesium compound include magnesium alcoholates such as magnesium methylate and magnesium ethylate. The liquid carrier contained in both fluororubber paints is selected from organic solvents such as lower ketones, lower esters, and cyclic ethers, water, and mixtures of water and water-soluble organic liquids, and the water-soluble organic liquids include alcohols. can be exemplified. Among these liquid carriers, water is most preferred from the viewpoint of painting workability and not damaging the inner insulating layer or the rubber layer or resin layer of the heat generating layer. Furthermore, inorganic fibrous substances as other substances contained in both fluoro rubber coatings are used to improve the compression recovery properties of the fluoro rubber coating, and representative examples include glass fiber, carbon fiber, Examples include asbestos fibers and potassium titanate fibers. This inorganic fibrous material has an average length of at least 1μ,
The thickness is preferably 1 to 100μ. In addition, the amine compound added to both fluororubber paints, if desired, primarily functions as a vulcanizing agent for the fluororubber, and together with the coupling agent, improves mechanical properties. Examples of such compounds include monoamines such as ethylamine, propylamine, butylamine, benzylamine, allylamine, n-amylamine, and ethanolamine, ethylenediamine, trimethylenediamine, tetramethylenediamine, hexamethylenediamine, 3,9-bis(3- diamines such as (aminopropyl)-2,4,8,10-tetraoxaspiro[5,5]undecane (hereinafter referred to as V-11), polyamines such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine Among these, amine compounds having two or more terminal amino groups are preferred. The fluororesin preferably contained in the fluororubber paint for the outer insulating layer includes polytetrafluoroethylene, tetrafluoroethylene, and at least one other ethylenically unsaturated monomer copolymerizable therewith (e.g., ethylene, Olefins such as propylene, halogenated olefins such as hexafluoropropylene, vinylidene fluoride, chlorotrifluoroethylene, vinyl fluoride,
copolymers with perfluoroalkyl vinyl ethers, polychlorotrifluoroethylene,
Examples include polyvinylidene fluoride.
Among these, preferred fluororesin is at least one of polytetrafluoroethylene, tetrafluoroethylene and hexafluoropropylene, perfluoromethyl vinyl ether, perfluoroethyl vinyl ether, and perfluoropropyl vinyl ether (usually 40 mol% based on tetrafluoroethylene). (included below). As the conductive substance added to the conductive material including the conductive fluororubber paint, conventionally used substances such as carbon, graphite, and metal are used. Channel black, furnace black, thermal black, etc. are included, and metals include gold, silver, copper, aluminum, titanium, etc. To prepare such conductive fluororubber paints and fluororubbers for outer insulating layers, pigments, acid acceptors, and fillers are usually added to a mixture of fluororubber, liquid carrier, and optionally fluororesin. Further, if necessary, an inorganic fibrous substance and, in the case of a conductive fluororubber paint, a conductive substance are blended in a conventional manner, and the coupling agent and, if necessary, an amine compound are added to the resulting dispersion. (additives such as surfactants, pigments, acid acceptors, fillers, etc. may be added as necessary) and thoroughly mixed by a conventional method to obtain a uniform fluororubber paint. The amount of coupling agent added is usually fluoro rubber.
1 to 50 parts by weight per 100 parts by weight, preferably 1 to 50 parts by weight
It is 20 parts by weight. When an amine compound is added as desired, it is blended so that the total sum of the coupling agent and the amine compound meets the above value. in this case,
The molar ratio of the coupling agent to the amine compound is selected from the range of 1:99 to 99:1. The reason why fluororesin is added to the fluororubber paint for the outer insulating layer is to impart excellent non-adhesive properties to the surface of the fluororubber coating. Therefore, when adding a fluororesin, it is desirable that the ratio of fluororubber to fluororesin is 95:5 to 35:65 by weight.If the ratio of fluororesin is less than the above lower limit, The improvement in non-adhesiveness and lubricity is insufficient; on the other hand, if the amount exceeds the above upper limit, a coating film of the desired thickness cannot be obtained, and cracks and pinholes are likely to occur in the coating film. The amount of the conductive substance added to the conductive paint may be such that the cured paint film becomes a surface heating element and has a volume resistivity of 10 ² Ω-cm or less. As the acid acceptor, those commonly used in the vulcanization of fluororubber can be similarly used, such as one or more divalent metal oxides or hydroxides. Specific examples include oxides or hydroxides of magnesium, calcium, zinc, lead, and the like. Further, as the filler, silica, clay, diatomaceous earth, talc, carbon, etc. are used. The conductive paint is applied to the outer circumferential surface of a roll provided with an inner insulating layer (if necessary) by a conventional coating method, and then applied under conditions suitable for each paint, such as the above-mentioned preferred conductive paint. In the case of raw rubber paints, the heating layer coating is formed by curing at a temperature of room temperature to 400°C, preferably 100 to 400°C, for an appropriate period of time. When forming this heat generating layer, appropriate electrodes and lead wires are coated on the coating film. After forming the heat generating layer, various paints for the outer insulating layer are applied thereon under conditions suitable for each, for example, for the above-mentioned preferred fluoro rubber paint for the outer insulating layer, the heating temperature is from room temperature to 400°C, preferably from 100°C to 400°C. By curing at a temperature of 400° C. for an appropriate period of time, an outer insulating layer coating can be formed. Since the heating roll of the present invention has a heating layer made of a conductive coating film, there is almost no possibility of wire breakage or wear due to the conventional method, and it can withstand long-term use and can be made smaller and lighter. . Also, because the heat generating part is located near the surface, there is less heat loss. Furthermore, if a coating film obtained from the above-mentioned fluororubber for an insulating layer containing a fluororesin is used as the insulating layer, excellent non-adhesive properties can be imparted to the surface. The present invention will now be described with reference to the accompanying drawings regarding a fixing roll in an electrostatic printing device. In the electrostatic printing process using the xerographic method shown in FIG. 1 is exposed to light to form an electrostatic latent image of the original plate 4 on the photoreceptor 1. This electrostatic latent image is developed by adhering toner 5, and the obtained toner image is transferred to a printing material 6, and is further heat-fused and fixed to the printing material by a fixing roll 7, resulting in a printed material 8. obtain. As shown in FIGS. 2 and 3, the fixing roll 7 has an inner insulating layer 9 on the outer peripheral surface of the metal roll 7a.
A heat generating layer 10 and an outer insulating layer 11 are sequentially provided. Next, examples will be shown to specifically explain the present invention. Note that parts are by weight. Example 1 (1) to (7) A cylindrical iron roll with an inner diameter of 27 mm, an outer diameter of 34 mm, and a length of 113 mm was coated with Daiel Latex GL-252 (a fluoro rubber water-based paint manufactured by Daikin Industries, Ltd.),
Next, a paint containing fluororubber, conductive carbon/graphite (4:6), and V-11 in a solid content ratio of 100:45:2 (carrier: a 1:1 mixture by weight of methyl ethyl ketone and methyl isobutyl ketone) ) was applied and cured to create a heat generating layer. Above this is the following

[Table] Example 2 A smooth coating film was prepared from the paint consisting of liquids A and B used in Example 1, one drop of pure water was dropped onto the surface at 24°C, and the contact angle of water was measured using a goniometer. (manufactured by Elma Optical Co., Ltd.). The contact angle is
It was 110°. Further, when the contact angle of water was similarly measured for a fluoro rubber vulcanized plate (DAIEL G-702 manufactured by Daikin Industries, Ltd.), it was 76°. It is thus understood that the coating film obtained from the fluororubber paint of Example 1 has excellent non-adhesive properties. Example 3 On the surface of the heating roll obtained in Example 1, 100 parts of Picolastic D125 (styrenic resin manufactured by Esso Standard Sekiyu Co., Ltd.) and Peerless 155 (Columbia Co., Ltd.) were applied.
A toner with an average particle diameter of approximately 15μ consisting of 5 parts of Ribbon & Manufacturing Co., Ltd.) and 5 parts of Oil Black BW (Orient Chemical Industry Co., Ltd.) was applied and fused at 150°C for 10 seconds. After cooling, the toner was subjected to a peel test. That is, the roll was rotated at a surface speed of 0.3 cm/sec while a load of 100 g was applied to the roll surface with a spatula in contact at an angle of about 30° to the fluororubber coated surface. As a result, complete peeling of the toner was observed with the roll of the present invention.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of the electrostatic printing process using the xerography method, Figure 2 is a perspective view of the roll according to the present invention used in the process, and Figure 3 is a partially enlarged section showing the surface condition of the roll. be. 7... Fixing roll, 7a... Roll, 9... Inner insulating layer, 10... Heat generating layer, 11... Outer insulating layer.

Claims (1)

[Claims] 1. An inner insulating layer, a heat generating layer, and an outer insulating layer are provided on the outer peripheral surface of the roll, if necessary, and the outer insulating layer contains fluorocarbon rubber, fluorocarbon resin, a coupling agent, and a liquid carrier. A heat generating roll characterized in that the coating layer is formed by applying and curing a fluoro rubber paint comprising: 2 The weight ratio of fluorocarbon rubber and fluorocarbon resin is 95:5 or more
The heating roll according to claim 1, which has a ratio of 35:65. 3. The heating roll according to claim 1 or 2, wherein the fluororubber coating further contains an amine compound and/or an inorganic fibrous substance. 4. The heat generating roll according to claim 1, wherein the heat generating layer is a coating layer formed by applying and curing a conductive paint. 5. The heating roll according to claim 4, wherein the conductive paint is a conductive fluororubber paint comprising fluororubber, a coupling agent, a conductive substance, and a liquid carrier. 6. The heating roll according to claim 5, wherein the conductive fluororubber coating further contains an amine compound and/or an inorganic fibrous substance.