JPH0150900B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an electrostatic recording material, and more particularly to an electrostatic recording material for pressure fixing that exhibits excellent adaptability when pressure fixing powder images. In the electrostatic recording method, a voltage pulse is applied from the front, back, or both sides of the dielectric layer of an electrostatic recording medium in which a dielectric layer made of insulating resin or the like is provided on a support that has been subjected to conductive treatment, or other methods are used. This is a method of forming an electrostatic latent image on a dielectric layer by transferring the electrostatic latent image formed on the original plate, and making it visible by developing it with toner, and is widely used in facsimiles, printers, etc. ing. Methods for developing electrostatic latent images on such electrostatic recording materials are broadly classified into powder development methods and liquid development methods. In the powder development method, the recording medium is generally developed with a powder toner and then passed through a heating oven to thermally fix the powder image, which tends to cause fixing failures due to insufficient temperature at startup. As the speed of the device increases, it requires higher temperature heating, which has the disadvantage of causing a fire risk. On the other hand, in a liquid developing method using a liquid toner in which toner particles are dispersed in a solvent, the fixing properties of the toner are not necessarily sufficient, and since an organic solvent is used, there are disadvantages such as fire danger and odor. In recent years, as a method to solve these difficulties, a so-called method has been developed in which the recording material after powder development is passed between pressurized metal rolls, and the toner particles are deformed under pressure and fixed to the dielectric layer on the surface of the recording material. The pressure fixing method is attracting attention. However, in this pressure fixing method, during pressure fixing, some of the toner particles that should originally be fixed on the surface of the recording medium adhere to the fixing metal roll, causing roll stains, and furthermore, the toner particles There is a problem in that a so-called offset phenomenon occurs in which the particles are transferred onto the recording medium again and a ghost image is generated.
As a countermeasure, in addition to improving the toner composition, such as improving the fixing properties of the toner particles or adding wax or the like to give the toner particles release properties from the metal roll, we also constantly clean the metal roll with a cloth impregnated with silicone oil. Improvements in equipment, such as maintaining the releasability of metal rolls, are also being considered. However, these improvements come with new difficulties. In other words, improving the fixing properties of toner particles and adding wax depend on electromagnetic properties,
This has a great influence on the properties fundamentally required of toner particles, such as fluidity and storage stability, and the method of cleaning metal rolls becomes less effective over time and poses maintenance problems. In view of the current situation, the inventors of the present invention have conducted extensive studies on a method for eliminating offset development during pressure fixing without impairing the electrical properties of toners and recording materials and without maintenance, and as a result, they have completed the present invention. Ivy. The present invention provides an electrostatic recording material for pressure fixing comprising a conductive support provided with a dielectric layer on one side, in which the other side of the conductive support is treated with a release agent specified in the claims. This is an electrostatic recording material for pressure fixing, which is characterized in that: As specific materials for the mold release agent, various materials used as mold release agents or lubricants in the molding industry of plastics, rubber, etc. can be used, and examples thereof include the following. Zinc stearate, calcium stearate,
Metal soaps such as barium stearate, aluminum stearate, magnesium stearate, zinc stearate/calcium stearate complex, zinc palmitate, lead laurate, nickel laurate, stearamide, ethylene bisamide stearate, palmitic acid amide, Fatty acid amides such as tridecylic acid amide, lauric acid amide, myristic acid amide, vinyl caprate, propyl laurate, heptyl myristate, decyl palmitate, isoamyl oleate, isobutyl ricinoleate, 1,17-heptadecamethylene dicarboxylic acid. Fatty acid ester wax such as G-n-dodecyl, aliphatic hydrocarbon wax such as paraffin wax, polyethylene wax, microcrystalline wax, chlorinated paraffin wax, stearic acid, capric acid, lauric acid, 2, Higher fatty acids such as 2-dimethyldodecanoic acid, 2-pentyldodecanoic acid, myristoleic acid, higher aliphatic alcohols such as lauryl alcohol, myristyl alcohol, stearyl alcohol, nonadecan-2-ol, glycerin, sorbitan, silicone resin, silicone oil and emulsions thereof, etc. Among these mold release agents, metal soaps, fatty acid amides, aliphatic acid hydrocarbon waxes, silicone resins, silicone oils, and emulsions thereof are particularly preferably used because they provide a uniform treatment solution and have excellent treatment effects. Among them, those in a solid state after being processed and dried on a conductive support are particularly preferably used because they do not transfer or diffuse into the dielectric layer and there is no risk of impairing the fixing properties of the toner. In the present invention, the method for obtaining a conductive support treated with a mold release agent is not particularly limited, as long as at least the surface of the conductive support not in contact with the dielectric layer is treated with a mold release agent. good. If a conductive layer is to be provided on a surface not in contact with the dielectric layer, if necessary, a mold release agent may be mixed into the conductive layer or may be treated anew on the conductive layer. The processing liquid used at this time is prepared by dissolving or dispersing the mold release agent in a suitable medium, and further adding adhesives, pigments, conductive substances such as conductive polymer electrolytes, etc. as necessary. Ru. The treatment solution thus prepared can be treated not only by a coating method using a bar coater, an air knife coater, a blade coater, etc., but also by an impregnation method using a size press, etc., but preferably by a coating method. The amount of release agent to be treated in the present invention varies depending on the material and structure of the fixing roll, the characteristics of toner particles, the type of release agent used, etc., and cannot be determined unconditionally, but a small amount will not be effective. On the other hand, if the amount is too large, the transfer to the metal roll will be excessive, which will not only cause paper feeding problems such as roll slippage and poor biting, but also may reduce handling suitability due to slipping of the recording body itself, so release the mold. Generally 0.001 to 2 g/m ² , preferably 0.01 to 1
It is preferable that the treatment be carried out in such a way that the amount is within the range of g/m ² . In the present invention, as mentioned above, the surface opposite to the dielectric layer is treated with a specific amount of mold release agent,
Despite this, the offset phenomenon that occurs on the dielectric layer during pressure fixing is extremely effectively prevented, which is thought to be due to the following mechanism. That is, when the recording medium of the present invention is pressurized between fixing rolls, an appropriate amount of the release agent is transferred to the roll that is in contact with the back side of the recording medium, and then this transferred release agent is transferred during idle operation, etc. This is thought to be because the release agent is further transferred to the roll in contact with the dielectric layer, and as a result, an appropriate amount of mold release agent is always applied to the roll on the dielectric layer side. Therefore, according to the recording medium of the present invention, the electrical properties of the dielectric layer or the toner fixing properties are not inhibited unlike when the dielectric layer is treated with a release agent, and offset can be extremely effectively achieved. The phenomenon is to be prevented. In the present invention, the conductive substance used in preparing the conductive support is not particularly limited, and substances commonly used in the field of electrostatic recording materials can be used, such as polyvinylbenzyl Trimethylammonium chloride, polymethacryloxyethyltrimethylammonium chloride, polymethacryloxyethyldimethyl-
β-hydroxyethylammonium chloride,
Conductive polymer electrolytes such as poly(N,N-dimethyl-3,5-methylene)piperidinium chloride, sodium polystyrene sulfonate, zinc oxide doped with aluminum, gallium, and indium, tin oxide doped with antimony, Electronically conductive powders such as tin-doped indium oxide and copper iodide, sodium chloride, potassium chloride, sodium oxalate, calcium chloride, sodium hydroxide,
Examples include inorganic compounds such as potassium hydroxide and calcium hydroxide. In the present invention, the conductive substances described above are prepared as a coating liquid by dissolving or dispersing them in water. When preparing the coating liquid, for example, polyvinyl alcohol, methyl cellulose, hydroxy Ethylcellulose, carboxymethylcellulose, starch, modified starch, polyvinylpyrrolidone, sodium alginate, polyacrylamide, styrene-butadiene copolymer latex, vinyl acetate latex,
Nonionic, weak anionic and cationic latexes such as acrylic acid latexes, adhesives such as styrene/maleic anhydride copolymer salts, isobutene/maleic anhydride copolymer salts, calcium carbonate,
barium sulfate, titanium oxide, clay, kaolin,
Inorganic and organic pigments such as zeolite, aluminum oxide, silicon oxide, aluminum hydroxide, polystyrene microballs, dispersants, antifoaming agents, dyes,
Various auxiliary agents such as ultraviolet absorbers may also be added as necessary. The coating liquid thus obtained is applied onto a common support substrate such as paper or synthetic paper, and a conductive layer is formed at least on the surface in contact with the dielectric layer, thereby preparing a conductive support. The coating solution can be applied to the supporting substrate not only by a coating method using a bar coater, an air knife coater, a blade coater, etc., but also by an impregnating method using a size press, etc., but preferably by a coating method. The amount of treatment is adjusted so that the surface electrical resistance value of the conductive support is 10 ⁶ to 10 ⁹ ohms at normal humidity, and the dry weight is usually 2 to 20 g/m ² , preferably 3 to 15 g/m ² . Painted or impregnated over a range of areas. In the present invention, the coating liquid for forming the dielectric layer may be organic solvent-based or aqueous dispersion, such as vinyl acetate resin, vinyl chloride resin, silicone resin, epoxy resin, acrylic resin, polyester resin, butyral resin, Vinyl acetate/crotonic acid copolymer, styrene/butadiene copolymer, vinyl chloride/vinyl acetate copolymer, vinylidene chloride/
Examples include organic solvent solutions or aqueous dispersions of insulating resins such as vinyl chloride copolymer, vinylidene chloride/acrylonitrile copolymer, etc., alone or as a mixture. It is not particularly limited in use in the body, and can be selected from among known insulating resins, and auxiliary agents normally contained in coating liquids, such as clay, kaolin, talc, and carbonic acid, can be used. Of course, calcium, barium sulfate, barium carbonate, titanium oxide, zinc oxide, alumina, calcined clay, inorganic pigments prepared by treating these with organopolysiloxane or beef tallow, polymer particles, starch powder, dyes, etc. can be added. This is not excluded, and the coating method can also be carried out using conventional coating equipment. The amount of coating is also not particularly limited, but is generally adjusted in a dry weight range of 2 to 10 g/m ² , preferably 4 to 7 g/m ² . The present invention will be explained in more detail with reference to Examples below, but it is of course not limited thereto. Further, unless otherwise specified, parts and % in the examples represent parts by weight and % by weight, respectively. Example 1 33% of polyvinylbenzyltrimethylammonium chloride was applied to one side of a 50 g/ ^m2 high-quality paper.
Aqueous solution (manufactured by Dow Chemical Company, product name ECR-34)
was applied and dried so that the dry coating amount was 3 g/m ² . Next, a 25% toluene solution made by mixing 40 parts of calcium carbonate (manufactured by Bihoku Funka Co., Ltd., trade name: Softon 1800) and 60 parts of butyral resin (manufactured by Sekisui Chemical Co., Ltd., trade name: BMS) was then dried and applied on top. A dielectric layer was formed by coating and drying in an amount of 5 g/m ² . Next, 100 parts (solid content equivalent) of a 33% aqueous solution of polyvinylbenzyltrimethylammonium chloride (manufactured by Dow Chemical Company, trade name ECR-34), calcium carbonate ( Thoroughly mix 50 parts of Softon 1800 (manufactured by Bihoku Funka Co., Ltd., trade name), 10 parts (solid content equivalent) of calcium stearate emulsion (manufactured by San Nopco Co., Ltd., trade name Nopcoat C-104) as a mold release agent, and 850 parts of water. The obtained coating liquid was applied and dried to a dry coating amount of 2 g/m ² to obtain an electrostatic recording paper for pressure fixing. Comparative Example 1 An electrostatic recording paper for pressure fixing was obtained in exactly the same manner as in Example 1 except that the emulsion of calcium stearate was not used. Comparative Example 2 An electrostatic recording paper for pressure fixing was obtained in the same manner as in Example 1, except that the amount of calcium stearate emulsion used was 0.05 part in terms of solid content. Examples 2 to 5 In Example 1, instead of the calcium stearate emulsion, 10 parts of a silicone resin emulsion (manufactured by Shin-Etsu Chemical Co., Ltd., trade name Poron C) (Example 2) and a polyethylene wax emulsion (manufactured by Allied Chemical Co., Ltd.) were used. , trade name A/C polyethylene) 30 parts (Example 3), 15 parts of stearamide emulsion (manufactured by Chukyo Yushi Co., Ltd., trade name Cellozol 187N) (Example 4), and self-emulsifying glycerin monostearate powder ( Four types of electrostatic recording paper for pressure fixing were obtained in exactly the same manner as in Example 1, except that 100 parts of Aratsucel 165 (manufactured by Kao Atlas Co., Ltd.) (Example 5) was used as a release agent. Note that the amounts used in Examples 2 to 4 represent solid content conversion values. The seven types of electrostatic recording paper for pressure fixing obtained in this way were transferred to a facsimile machine (manufactured by Matsushita Densen Co., Ltd., UF-
520), 30 consecutive copies were recorded in copy mode using the Electrophotography Society No. 2 test chart. The pressure fixing roll was thoroughly cleaned every time recording of 30 copies of one sample was completed. Then, evaluate the occurrence of the offset phenomenon and use the results as the first
Shown in the table.

[Table] As is clear from the results in Table 1, the electrostatic recording medium for pressure fixing of the present invention was an excellent recording medium in which the occurrence of offset phenomenon was extremely effectively prevented.

Claims (1)

[Claims] 1. In a pressure fixing electrostatic recording material comprising a dielectric layer provided on one side of a conductive support, the other side of the conductive support is made of metal soap, fatty acid amide, fatty acid ester wax, or aliphatic hydrocarbon. 1. An electrostatic recording material for pressure fixing, characterized in that it is treated with a release agent selected from waxes, higher fatty acids, higher aliphatic alcohols, silicone resins, silicone oils, and emulsions thereof.