JPH0455300B2 - - Google Patents

Description

[Detailed description of the invention]

Industrial Application Field The present invention is particularly useful for a one-shot color image forming method that uses light-transmitting particles containing a sublimable color former and applies electrophotographic technology to obtain a color image with one exposure and one development. Concerning image receptors. Specifically, the present invention relates to an image receptor capable of electrostatic transfer of the light-transmitting particles and capable of developing a sublimable color former. The present invention relates to an image receptor useful in an image forming method using light-transmissive particles containing a sublimable color former as disclosed in, for example, Japanese Patent Publication No. 55-49307. The requirements for an image receptor are: (1) conductive, light-transmitting particles can be electrostatically transferred, (2) sublimable color formers can be developed, and (3) particles can be easily removed from the image receptor after heat fixing. It is something that can be removed. Conventionally, as an image receptor having the above-mentioned requirements, an electrostatic clay paper disclosed in, for example, Japanese Patent Laid-Open No. 16143/1983 has been proposed. However, this electrostatic clay paper had the following problems related to the color developer of the sublimable color former. (1) Since the activated clay, which is a color developer, is colored light brown, the color purity of the colored image decreases. (2) The transparency of activated clay was poor, and it was difficult to make the coloring layer transparent. Therefore, a glossy and clear colored image could not be obtained. OBJECTS OF THE INVENTION It is an object of the present invention to provide an image receptor that overcomes these conventional problems. A first object of the present invention is to provide an image receptor capable of electrostatically transferring conductive particles and capable of producing glossy and clear dye-colored images. A second object of the present invention is to provide an image receptor with high whiteness. A third object of the present invention is to provide an image receptor in which the coloring layer is transparent. Structure of the Invention The image receptor of the present invention is provided with a coloring layer containing a color developer mainly composed of silicon dioxide having a pH of 6 or less on a substrate, and further having a surface resistivity of 10 ¹⁰ Ω or more on the coloring layer. By superimposing a transparent dielectric layer that allows the molecules of sublimable color former to pass through, conductive particles can be electrostatically transferred, and a glossy and clear colored image can be obtained. It is something. DESCRIPTION OF THE EMBODIMENTS The figure is a schematic cross-sectional view showing one embodiment of an image receptor according to the invention. A coloring layer 2 containing a dye developer is provided on a substrate 1, and a dielectric layer 3 is superimposed thereon. The substrate 1 may be made of paper with high whiteness such as high-quality paper or art paper, or vinylon, etc., depending on the purpose of use.
Transparency of cellophane, acetylcellulose, etc.
Appropriately selected heat-resistant plastic sheets are used. The color developing layer 2 is composed of a color developer as an essential condition, and other materials appropriately selected from a binder, a dispersant, a dye fading preventive agent, etc. as necessary. The color developer is silicon dioxide alone or mainly composed of silicon dioxide with a pH of 6 or less, and if necessary, activated clay or polyparaphenylphenol, 4,
It is used in combination with an appropriately selected electron-accepting substance such as 4'-diphenylpropane. In order to make the coloring layer transparent, silicon dioxide having a particle size of 0.1 micron or less is preferable, and colloidal silica with a pH of 6 or less is particularly preferable. The binder used is one that has strong binding power, is transparent, and has good dispersibility of the color developer. For example, styrene-butadiene copolymer, ethyl cellulose, acrylic resin, polyvinyl acetate, etc. are preferred. In particular, styrene-butadiene copolymer is suitable because when heated in the coexistence with silicon dioxide, it crosslinks and significantly improves heat resistance. The amount of the binder added is correlated with the coloring efficiency of the dye, and is preferably as small as possible. Preferably, the amount is 30% by weight or less based on the color developer. A conventional antioxidant or quencher can be used as a dye fading inhibitor. The dielectric layer 3 is made of an insulating resin that is transparent and has high resistance, or a mixture containing this as a main component and adding inorganic fine powder or a binder as necessary. As the dielectric material, a non-adhesive material is preferable. For example, polyethylene, silicone resin, etc. are suitable. Particularly preferred are low molecular weight resins. The dielectric layer must be permeable to the dye gas. For this purpose, it is desirable to make the dielectric layer porous. This can be achieved, for example, by containing a highly transparent inorganic fine powder such as silicon dioxide or barium sulfate. In order to strongly bind the dielectric layer to the color forming layer, the following binder is added to the dielectric layer. For example, styrene-butadiene copolymer, acrylic resin, polyvinyl acetate, etc. are suitable. Furthermore, in order to electrostatically transfer conductive particles, it is important that the surface resistivity of the dielectric layer is 10 ¹⁰ Ω or more. The image receptor of the present invention can also develop color using inking materials other than sublimable color formers, such as basic dyes and disperse dyes. Example 1 The following mixture was sufficiently stirred and mixed with a mixer to obtain a coloring layer liquid. Color developer: Silicon dioxide (Colloidal silica “Snowtex O” manufactured by Nissan Chemical Co., Ltd. PH2-4, solid content 20% by weight)
…100 parts by weight Binder: Styrene-butadiene copolymer (Nippon Zeon Co., Ltd.)
``Danbond'' manufactured by Danbond (solid content 40% by weight)...3 parts by weight Apply this liquid to art paper at 9g/m ² (weight after drying,
The same applies below) to form a coloring layer. Next, the following mixture was sufficiently stirred and mixed with a mixer to obtain a dielectric layer liquid. Dielectric material: Low molecular polyethylene (Sanyo Chemical Co., Ltd. "Permarin PN" solid content 20% by weight) ...100 parts by weight Inorganic fine powder: Silicon dioxide (Nissan Chemical Co., Ltd. colloidal silica "Snowtex C" PH8-9, solid content 20% by weight)
...30 parts by weight Binder: Styrene-butadiene copolymer ("Danbond") ...50 parts by weight This liquid was coated at 4 g/m ² on the above-mentioned coloring layer to obtain an image receptor. The surface resistivity of the image receptor is 1.2×
10 ¹² and Hunter whiteness was 82%. Example 2 The coloring layer liquid and dielectric layer liquid of Example 1 were coated on a vinylon sheet in the same amounts as in Example 1 to obtain a transmission type image receptor. At this time, the transmittance of the coloring layer is 90%,
Moreover, it was 82% as an image receptor. Example 3 The following mixture was sufficiently dispersed in a ball mill to obtain a coloring layer liquid. Color developer: Silicon dioxide "Snowtex O"...100 parts by weight Activated clay...4 parts by weight Binder: Styrene-butadiene copolymer "Danbond"
...4 parts by weight This liquid was applied to high quality paper at 8 g/m ² to form a coloring layer. Next, the following mixture was sufficiently dispersed and mixed in a ball mill to obtain a dielectric layer liquid. Dielectric material: Silicone resin (“SH7024” manufactured by Toray Silicone Co., Ltd., solid content 35% by weight) …100 parts by weight Inorganic fine powder: Barium sulfate …10 parts by weight This liquid was applied on the above-mentioned coloring layer at 4 g/m ² An image receptor was obtained by coating. The surface resistivity of the image receptor is 1.0×
10 ¹² Ω, Hunter whiteness was 80%. Experiment 1 Magenta sublimable color former 7'-diethylamino-1,3,3,5-tetramethyl-
Using conductive, light-transmitting particles containing indolinobenzospiropyran (particle specific resistance: 2 x 10 ³ Ωcm), zinc oxide was photosensitive by the image forming method disclosed in Japanese Patent Publication No. 1983-49307. Particle images were obtained on the body. Next, after exposing the entire surface to light to remove the electrostatic adhesion force between the particles and the photoreceptor, the image receptor is brought into close contact with the particle image, and a corona charger applying +6KV is used to electrostatically charge the particle image to the image receptor. Transcribed. After transfer, 200℃, 1
After heating the image receptor at 1 Kg/cm ² for 2 seconds,
Particles were removed. When the image receptors of Examples 1 to 3 were tested using the above method, glossy and clear magenta colored images as shown in the table were obtained. For comparison, the results of electrostatic clay paper using activated clay as the main component of the color developer disclosed in Example 1 of JP-A-56-16143 are also listed for reference.

[Table] Effects of the Invention As explained above, the image receptor of the present invention uses silicon dioxide, which has excellent transparency, as the main component of the color developer, so that the coloring layer can be made transparent.
Therefore, the degree to which the dye developed in the lower part of the coloring layer is hidden by the upper color developer and the coloring density is reduced is extremely small, and a glossy dye image with high coloring density can be obtained. Also, the coloring layer can be made transparent. The use of a transparent substrate has the effect that a transmission type image can be easily obtained. Furthermore, since silicon dioxide is colorless and heat resistant, it does not yellow due to heat and has the effect of providing a dye image with high color purity.

[Brief explanation of the drawing]

The figure is a schematic cross-sectional view showing one embodiment of an image receptor according to the invention. 1...Substrate, 2...Coloring layer, 3...Dielectric layer.

Claims (1)

[Scope of Claims] 1. Color development of the color former by heating in close contact with particles containing a sublimable color former formed in an imagewise manner to sublimate the color former, and then removing the particles. The structure is such that a coloring layer capable of coloring a sublimable color former mainly composed of silicon dioxide having an upper limit of pH 6 is provided on a substrate, and a surface resistivity of 10 ^{to 10} is provided on the coloring layer.
1. An image receptor comprising a dielectric layer having a lower limit of Ω and being transparent to molecules of a sublimable color former. 2. The image receptor according to claim 1, wherein in the coloring layer, silicon dioxide is finely dispersed in a binder and is made transparent. 3. An image receptor according to claim 2, wherein the amount of binder is up to 30 weight percent based on silicon dioxide. 4. The image receptor according to claim 3, wherein the binder is a styrene-butadiene copolymer. 5. The image receptor according to any one of claims 1 to 4, wherein the dielectric layer contains a release agent, silicon dioxide having a pH of up to 6, and a binder. 6. The image receptor according to claim 5, wherein the release agent is polyethylene.