JPH0411862B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention applies electrophotographic technology to perform one-time exposure,
The present invention relates to an image receptor particularly useful in one-shot color imaging processes that produce color images in a single development. Specifically, light-transparent particles that have a color separation function and contain a colorless sublimable dye that reacts with a color developer to develop color are electrostatically attached to a charged photoconductive photoreceptor.
After image exposure, particles whose electrostatic attraction has been weakened or removed are mechanically or electrically removed from the photoreceptor to obtain a particle image, and the particle image is electrostatically transferred to an image receptor containing a color developer. , a method in which the colorless sublimable dye contained in the particles is sublimated by heating, the developer and the dye are reacted to form a color on the image receptor, and then the particles are removed from the image receptor to obtain a colored image. Regarding suitable image receptors. More specifically, the present invention relates to an electrostatic clay paper in which a dielectric layer through which molecules of a colorless sublimable dye can pass is superimposed on a layer containing activated clay as a color developer. Conventionally, electrostatic clay paper has a coloring layer containing activated clay and having a surface resistivity of 10 ⁹ Ω or less on a base paper, and a dielectric layer that allows colorless sublimable dye molecules to pass through is superimposed on the coloring layer. is proposed. (For example, Japanese Patent Application Laid-Open No. 16143/1983). However, since a base paper that is not conductively treated or a base paper that is conductively treated with a polymer electrolyte is used as the base paper, there is a drawback that stable images cannot be obtained in a low humidity atmosphere. Therefore, it is an object of the present invention to provide an electrostatic clay paper which overcomes such conventional drawbacks. That is, an object of the present invention is to provide an electrostatic clay paper that is capable of stably recording images from a low humidity region to a high humidity region. Another object of the present invention is to provide electrostatic clay paper from which particles can be easily removed after color development by heating. Still another object of the present invention is to provide an electrostatic clay paper capable of producing clear colored images with high density. Furthermore, another object of the present invention is to provide electrostatic clay paper that has good particle transfer efficiency, excellent resolution, and is capable of producing clear images without blur. The electrostatic clay paper according to the present invention has a coloring layer containing activated clay on one side of the base paper, contains a release agent and white inorganic fine powder on the coloring layer, and is permeable to colorless sublimable dye molecules. It is characterized in that dielectric layers are superimposed, and a conductive layer containing an ion-conducting material and an electron-conducting material and having a surface resistivity of 10 ⁹ Ω or less is further provided on the opposite side of the base paper. Next, the structure of the electrostatic clay paper according to the present invention will be explained in more detail based on the drawings. The figure shows a schematic cross-sectional view of an electrostatic clay paper according to the present invention, in which a coloring layer 3 containing an activated clay 2 is formed on one side of a base paper 1.
Further, a dielectric layer 4 is superimposed on the coloring layer, and a conductive layer 7 containing an ion conductive material 5 and an electron conductive material 6 is provided on the opposite side of the base paper 1.
The coloring layer 3 is a layer containing activated clay as a main component and other white inorganic fine powder 8 dispersed in a resin binder (hereinafter simply referred to as binder). In addition, the fine powder is preferably one that is effective in preventing yellowing of the coloring layer due to heating, improving heat resistance, preventing bleeding of the coloring layer, and as a coloring aid. Typical examples include calcium carbonate and silicon oxide. be. As a binder,
It is desirable to have a strong binding force and little thermal yellowing, such as styrene-butadiene copolymer, acrylic resin, polyvinyl acetate, etc.
In particular, emulsions of the above resins are preferred in that they do not easily hide the activated clay and therefore increase the color density. The ratio of the materials constituting the coloring layer explained above is 20 to 80 parts by weight of inorganic fine powder to 100 parts by weight of activated clay to prevent yellowing of the coloring layer and improve heat resistance.
It is preferable to use the binder in an amount of 10 to 30 parts by weight. Further, when dispersing and mixing the various materials, a dispersant such as a surfactant may be used as necessary. In addition, the coating amount is 5 to obtain sufficient color density.
~10 g/ ^m2 is preferred. Further, the applied coloring layer is preferably calendered to make the surface resistivity uniform. Further, the base paper is not particularly limited, but in order to make the coated surface uniform, it is preferable to use high-quality paper that has good smoothness with few irregularities and does not repel liquid. The dielectric layer 4 is composed of a release agent 9 to prevent the particles from sticking after fixing, a white inorganic fine powder and a binder to facilitate the permeation of the sublimated gas of the colorless sublimable dye. As the release agent 9, it is desirable to use a transparent or white material with high resistance, and representative examples thereof include:
Polyethylene and silicone resin are preferred. In particular, emulsions of these materials are preferred because they have excellent compatibility with binders. The white inorganic fine powder is preferably silicon oxide, which is effective as a coloring aid.
The binder preferably has high resistance, is transparent, has good binding properties with the coloring layer, and has strong bending strength, such as styrene-butadiene copolymer, acrylic resin, polyvinyl acetate, and the like. In particular, emulsions of these resins are preferred because they have excellent air permeability. The ratio of the various materials constituting the dielectric layer explained above is 100 parts by weight of the stripping agent, and 20 parts by weight of the inorganic fine powder to sufficiently transmit the colorless sublimable dye molecules.
~60 parts by weight, and the binder is preferably 60 to 150 parts by weight in order to strengthen the coating strength of the dielectric layer. Further, when dispersing and mixing the various materials, a dispersant such as a surfactant or a thickener may be used as necessary. In addition, in order to shorten the sublimation path of the colorless sublimable dye, increase color density, and further improve transfer efficiency, it is desirable that the coating amount be high resistance and thin.
2 to 5 g/m ² is preferred. The conductive layer 7 has a surface resistivity of 10 ⁹ Ω or less even in a low humidity atmosphere, and is made of an ion conductive material and an electronic conductive material in order to serve as an electrode that prevents particles from scattering due to the applied voltage during electrostatic transfer. This is a layer containing Examples of ion conductive substances include Licl,
Inorganic salts such as Nacl, Kcl, Mgcl ₂ , Cacl ₂ , etc., anionic or cationic conductivity such as sodium polystyrene sulfonate, sodium polyacrylate, polyvinylbenzyltrimethylammonium chloride, polydiallyldimethylammonium chloride, polyvinyltrimethylammonium chloride, etc. Examples include conductive pigments such as resins, alumina sol, silica gel, metastannic acid sol, and zeolite, and antistatic agents such as stearyltrimethylammonium chloride, lauryltrimethylammonium chloride, sodium ricinoleate sulfate, and sodium alkylbenzenesulfonate. Examples of electronically conductive substances include AgCl, AgI,
Halides such as CuCl, CuI, TiO ₂ , Tl ₂ O,
Oxides such as Al ₂ O ₃ , Ta ₂ O ₅ , SnO ₂ , PbO, ZnO,
Sulfides such as ZnS, InSb, Mg ₂ Si, ZnSb, AlSb,
Examples include intermetallic compounds such as InAs, InSb, AlP, GaP, and InP, and carbon black.
In the present invention, the ^{10 -2} ~10 ³ Ω・
An electronically conductive powder with a resistivity of cm is preferred,
Among these, zinc oxide powder and titanium oxide powder having the above-mentioned specific resistivity are most preferred. The ratio of the various materials constituting the conductive layer described above is preferably in the range of 5 to 100 parts by weight of the ionically conductive material per 100 parts by weight of the electronically conductive material. In addition, as necessary, polyvinyl alcohol, methyl cellulose, hydroxyethyl cellulose, starch, modified starch, styrene-butadiene copolymer latex, vinyl acetate latex, acrylic acid latex, isobutene-maleic anhydride copolymer salt, styrene-maleic anhydride Binders such as acid copolymer salts, polyacrylic salts and soda, and inorganic or organic pigments such as clay, kaolin, aluminum hydroxide, aluminum oxide, calcium carbonate, barium sulfate, and polystyrene microballs, as well as antifoaming agents and dispersions. Agents, dyes, ultraviolet absorbers, etc. may be used as appropriate. In addition, the coating amount should be 2 to keep the surface resistivity below 10 ⁹ Ω even in a low humidity atmosphere.
~10 g/ ^m2 is preferred. Further, the applied conductive layer is preferably calendered to make the surface resistance uniform. Hereinafter, the present invention will be explained in more detail with reference to Examples. Example 1 First, solutions (1), (2), and (3) were prepared according to the following formulations.

[Table] 435 parts by weight of water was further added to the above materials and dispersed in an attritor for 30 minutes to obtain a coloring layer liquid. In this case, calcium carbonate was dispersed in advance with water in an attritor for 1 hour.

[Table] 250 parts by weight of water was further added to the above materials to obtain a conductive layer liquid. Next, 8 g/m ² (weight after drying, the same applies hereinafter) of the coloring layer liquid was applied to one side of a high-quality paper, and the paper was calendered. Furthermore, 3 g/m ² of dielectric layer liquid was applied on this coloring layer.
Coated and calendered. Furthermore, 7 g/m ² of the conductive layer liquid was applied to the opposite side of the above-mentioned high-quality paper and calendering was performed to obtain electrostatic clay paper. The surface resistivity at 20℃ and 60% RH is 3.5×10 ¹³ Ω for the dielectric layer and 4.9× for the conductive layer on the back side.
It was 10 ⁷ Ω. Furthermore, the surface resistivity in a low humidity atmosphere of 20° C. and 15% RH was 6.5×10 ¹⁶ Ω for the dielectric layer, and 2.7×10 ⁸ Ω for the conductive layer on the back surface. Next, in an atmosphere of 20°C and 60% RH, a dielectric layer of electrostatic clay paper was placed on a particle image containing a colorless sublimable dye formed on a photosensitive plate coated with dye-sensitized zinc oxide on an aluminum plate. The layer surfaces were brought into close contact with each other, and a voltage of +1.2 KV was applied to the conductive layer of the photosensitive plate and the conductive layer surface of this clay paper to perform electrostatic transfer by applying pressure. At this time, 90% of the particles were transferred onto the clay paper, and there was almost no blur in the transferred particle image. Furthermore, in order to obtain a colored image, pressure fixing was performed for 1.5 seconds on a hot plate heated at 230°C. After fixing, particles were removed with a fur brush, and a clear image with no particles attached, sufficiently developed color, and no fog was obtained. Further, electrostatic transfer was performed in the same manner as above in a low humidity atmosphere of 20° C. and 15% RH. At this time, 80% of the particles were transferred onto the clay paper, and there was almost no blurring in the transferred particle image. Furthermore, after color development by heating, particles were removed with a fur brush, and a clear image without any adhesion of particles, sufficiently developed color, and no fog was obtained. Example 2

【table】

[Table] Thorium salt

Claims (1)

[Scope of Claims] 1. An electrostatic clay paper in which a color-forming layer containing activated clay is provided on one side of a base paper, and a dielectric layer that can transmit molecules of a colorless sublimable dye is superimposed on the color-forming layer. An electrostatic clay paper characterized by having a conductive layer containing an ion conductive material and an electronic conductive material and having a surface resistivity of 10 ⁹ Ω or less on the opposite side of the paper. 2. 150 kg /
The electrostatic clay paper according to claim 1, which is a zinc oxide powder having a specific resistance of 10 ^-2 to ^{10 3} Ω·cm under a pressure of 1 cm ² . 3. The electron conductive material of the conductive layer is heated to 10 ^-2 under a pressure of 150 kg/cm ² with a conductive film of another metal formed on the surface.
The electrostatic clay paper according to claim 1, which is a titanium oxide powder having a specific resistance of ~10 ³ Ω·cm.