JPS6019499B2 - Electrostatic clay paper - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image receptor particularly useful in a one-shot color image forming method that applies electrophotographic technology to obtain a color image by one exposure and one development.

Specifically, light-transparent particles containing a colorless sublimable dye that has a color separation function and develops color by reacting with a color developer are electrostatically attached to a charged photoconductive photoreceptor, and 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, followed by heating. An image receptor that is subjected to a method in which a colorless sublimable dye contained in the particles is sublimated, and the particles are removed from the image receptor to obtain a colored image after the colorless sublimable dye contained in the particles is sublimated, and the particles are removed from the image receptor to form a color by reaction with the head coloring agent. Regarding. More specifically, it relates to an electrostatic clay paper in which a dielectric layer that is permeable to molecules of a colorless sublimable dye is placed on top of a coloring layer containing activated clay as a color developer. Conventionally, an electrostatic clay paper has been proposed in which a coloring layer containing activated clay is provided on a base paper conductively treated with a polymer electrolyte, and a dielectric layer made only of a resin such as ethyl cellulose is provided on the coloring layer.

However, when the particles are heated to develop color, the resin softens, so the particles tend to adhere to the image receptor, resulting in contamination of the image. Furthermore, the active clay is hidden by the resin, resulting in a low color density. Furthermore, since a conductive-treated base paper is used, there is a drawback that the manufacturing process is increased and the cost is increased. 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 electrostatic clay paper from which particles can be easily removed after color development by heating. Another object of the present invention is to provide an electrostatic clay paper that does not particularly require conductive treatment of the base paper. 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 can produce clear images without blur.

The electrostatic clay paper according to the present invention contains an activated clay that develops a colorless sublimable dye or a sublimable dye such as a disperse dye on a base paper such as synthetic paper or plain paper, and has a surface resistivity of 1 pi or less. The present invention is characterized in that a color-forming layer is provided, and a dielectric layer containing a release agent and white inorganic fine powder and capable of passing sublimable dye molecules is superimposed on the color-forming layer.

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 activated clay 2 is provided on a base paper 1, and a dielectric layer 4 is further placed on top of the coloring layer. be.
The coloring layer 3 is a layer containing activated clay as a main component, with white inorganic fine powder 5 dispersed in a resin binder (hereinafter simply referred to as binder), and having a surface resistivity of 1 piQ or less. Therefore, the activated clay preferably has a low powder resistance so that it can serve as an electrode that prevents particles from scattering due to the applied voltage during electrostatic transfer. The fine powder is preferably one that prevents the coloring layer from deteriorating due to heating, improves heat resistance, prevents the coloring layer from bleeding, and is effective as a coloring agent. Typical examples include calcium carbonate and silicon oxide. be. As the binder, it is desirable to have a strong binding force and less yellowing due to heat, such as styrene-butadiene copolymer, acrylic resin, polyvinyl acetate, and the like. In particular, emulsions of the above resins are preferred in that they do not easily hide the activated clay and therefore increase the coloring density. The ratio of the various materials constituting the coloring layer explained above is 10 parts by weight of activated clay, and 20 to 80 parts by weight of inorganic fine powder to prevent yellowing of the coloring layer and improve heat resistance.
It is preferable to use the binder in a range of 10 to 3 parts by weight in order to reduce the surface resistivity to 1 pi or less and to provide film strength.

Further, when dispersing and mixing the various materials, a dispersant such as a surfactant may be used as necessary. Further, the coating amount is preferably 5 to 10 ta in order to lower the surface resistance and obtain sufficient color density. Furthermore, the applied coloring layer is preferably calendered to make the surface resistance 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. Moreover, it goes without saying that a base paper that has been subjected to conductive treatment can also be used. The dielectric layer 4 is composed of a release agent 6 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 sublimable dye.

The surface resistivity of the dielectric layer 4 is preferably 1 to 20 or more in order to improve particle transfer efficiency.

As the release agent 6, it is desirable to use a transparent or white material with high resistance, and representative examples thereof include polyethylene,
Silicone resins 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 proportions of the various materials constituting the dielectric layer explained above are as follows: 10 parts by weight of the release agent, 20 to 60 parts by weight of the inorganic fine powder to allow sufficient penetration of sublimable dye molecules, and 20 to 60 parts by weight of the binder. is preferably 60 to 15 parts by weight to increase 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. Furthermore, the coating amount is desirably high in resistance and thin in order to shorten the sublimation path of the sublimable dye, increase color density, and further improve transfer efficiency, and preferably 2 to 5 coatings per coat. Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 First, liquids '11 and '2} were used according to the following formulations.

(1) Coloring Layer Liquid 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. (2) Dielectric layer liquid The above materials were mixed together to obtain a dielectric layer liquid.

Next, the coloring layer liquid was coated on a high-quality paper for 8 days per pillow (weight after drying, hereinafter the same) and calendered. Furthermore, a dielectric layer solution was applied on this coloring layer for 3 days and calendering was performed to obtain electrostatic clay paper. The surface resistivity in an atmosphere of 20° C. and 60% RH was 8.5×1 p0 for the coloring layer, and 2.4×1 and 2Q for this system.

Next, the conductive layer surface of the electrostatic clay paper is brought into close contact with the particle image containing the colorless sublimable dye formed on the photosensitive slope, which is formed by coating dye-sensitized zinc oxide on the aluminum slope, and the conductive layer of the photosensitive plate is Layer 11 on the back of this clay paper. Electrostatic transfer was performed by applying a voltage of Fox V and 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, the same results were obtained whether the particles were insulative or conductive. Further, in order to obtain a colored image, pressure fixing was carried out for 1.5 seconds on a hot plate heated to 23-0. 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. Example 2 A coloring layer was provided on high-quality paper in the same manner as in Example 1, and the same weight part of silicone resin (Toray Silicone, manufactured by Toray Silicone ■) was added in place of polyethylene in the dielectric layer liquid, and the dielectric layer was covered. Electrostatic clay paper was obtained.

The surface resistivity of this system was 5.3×1 and 20. The colored image obtained in the same manner as in Example 1 was a clear image with no particles, sufficient color development, and no fog.

As described above, in the electrostatic clay paper according to the present invention, since the coloring layer is a conductive layer, there is no need to particularly conductive treatment of the base paper, and the manufacturing cost is reduced.

Furthermore, there is an effect that a clear image with good resolution can be obtained with less blurring of the image due to scattering of particles during electrostatic transfer. In addition, the inorganic fine powder contained in the coloring layer has the effect of improving heat resistance and reducing yellowing of the fabric due to heating. Furthermore, when silicon oxide or calcium carbonate is used as the inorganic fine powder, the fine powder can also serve as a coloring aid, which has the effect of increasing image density. Moreover, by using the fine powder, a colored image without bleeding can be obtained. Further, since the dielectric layer contains a release agent, particles can be easily removed after heat fixing, and a clear image without residual particles can be obtained.

Furthermore, since the dielectric layer is a layer with high resistance, the transfer efficiency is good. Further, when silicon oxide is used for the dielectric layer, sublimable dye molecules can be easily transmitted through the dielectric layer, which has the effect of providing a clear colored image with high density. Further, according to the present invention, since the constituent materials of the coloring layer and the dielectric layer can be made water-soluble, manufacturing is easy and costs are reduced.

Furthermore, it can also be applied as electrostatic recording paper.

[Brief explanation of the drawing]

The drawing is a schematic vertical cross-sectional view of electrostatic clay paper according to an embodiment of the present invention. 1...Base paper, 3...Coloring layer, 4...
・Dielectric layer.

Claims (1)

[Claims] 1. Contains activated clay on the base paper and has a surface resistivity of 1.
An electrostatic clay paper characterized in that a coloring layer having a resistance of 0^9Ω or less is provided, and a dielectric layer containing a white inorganic fine powder and permeable to sublimable dye gas is superimposed on the coloring layer. 2. The electrostatic clay paper according to claim 1, wherein the dielectric layer has a surface resistivity of 10^1^2Ω or more. 3. The electrostatic clay paper according to claim 1, wherein the coloring layer contains at least one of calcium carbonate and silicon oxide. 4. The electrostatic clay paper according to claim 1, wherein the dielectric layer contains a release agent, silicon oxide, and a resin binder.