JPS5878148A - Multicolor recording medium - Google Patents

Abstract

PURPOSE:To obtain a multicolor recording medium enabling easy color recording in a simple developing stage by forming a photosensitive layer changing the adhesive property under irradiated light and a layer of a mixture of transparent colored particles having a plurality of colors on a substrate in order. CONSTITUTION:A binder is mixed with a photopolymerizable monomer and a dye redox polymn. initiator contg. >=2 kinds of dyes, and the mixture is applied to a substrate to form a photosensitive layer 2. A layer 1 of a mixture of microencapsulated transparent colored particles having >=2 kinds of colors is then laid on the layer 2 to obtain the desired multicolor recording medium. When green light is irradiated on the recording medium, only the green particles G transmit the light, the layer 2 under the particles G causes a photopolymn. reaction, and the adhesive property of the photosensitive part 4 to the substrate 3 is improved as compared to that of the unexposed part. Accordingly, by removing the unreacted layer 2 with a suitable solvent after the exposure, only the green particles G are left and the blue and red particles B, R are removed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording medium that forms a color image using light.

With the recent development of two-microcomputers and the like, there has been a desire for an economical color recording medium with a simple development process. In particular, since microcomputer display terminals are already colorized, multicolor recording media in the form of copies of these display terminals are promising in terms of miniaturization and economicalization of output terminals.

Color photographs and color copying materials can be used for such purposes.

In the past, various methods have been proposed for color photography or color copying materials, but silver salt chemical photography is the most common one that has been put into practical use, and more recently electrophotography and inkjet printers have been used. Color recording is being carried out.

However, although silver halide photography has high sensitivity, it has disadvantages such as being expensive and requiring a long process to form an image because it uses silver.On the other hand, color electrophotography However, color inkjet printers have the disadvantage that, in addition to being relatively expensive, they have poor maintainability due to clogging of ink nozzles.

SUMMARY OF THE INVENTION In order to eliminate these drawbacks, it is an object of the present invention to provide a multicolor recording medium that allows color recording through a simple development process, even if the sensitivity is somewhat poor.

That is, to summarize the present invention, the present invention comprises a substrate, a lower layer of a photosensitive layer whose adhesion changes depending on irradiation light, and a layer of a mixture of transparent colored particles of two or more colors on the photosensitive layer. The present invention relates to a multicolor recording medium characterized by the following features:

Hereinafter, the present invention will be described in detail based on the accompanying drawings. FIG. 1 is a schematic cross-sectional view schematically showing an embodiment of the multicolor recording medium of the present invention.

In FIG. 1, 1 means transparent colored particles, 2 means a photosensitive layer, and 3 means a substrate. In this example, the colored particles are composed of three colors: blue), red (b), and green (CG). The photosensitive layer 2 may have a photosensitive band in the entire visible light range or only in the wavelength band through which the colored particles of B, R, and G are transmitted.

FIG. 2 is a graph showing the relationship between wavelength (nm) (horizontal axis) and transmittance (1) (vertical axis) to schematically show the transmission characteristics of additive coloring. FIG. 3 is a schematic cross-sectional view schematically showing the state of the multicolor recording medium of FIG. 1 after being exposed to green light. FIG. 4 is a schematic cross-sectional view schematically showing the state of the medium illustrated in FIG. 3 after development. In FIGS. 3 and 4, 4 indicates a photosensitive portion of the photosensitive layer.

When green light is irradiated onto the medium configured as shown in FIG. 1, only the green particles (G) transmit the light, and the photosensitive layer below reacts to form the photosensitive area 4, as shown in FIG. Ru. Of course, as shown in FIG. 3, the photosensitive layer in the gaps between the transparent colored particles also reacts with the light to form the photosensitive areas 4.

This reaction caused by light is a photopolymerization reaction,
If this improves the adhesion between the substrate 3 and the photosensitive area 4 compared to the unexposed area, if the unreacted photosensitive layer 2 is removed with an appropriate solvent after exposure, the adhesiveness between the substrate 3 and the photosensitive area 4 can be improved as shown in FIG. Only green particles 0) are left behind. Of course, the photosensitive area 4 in the gap described above also remains on the substrate-L, but since the part involved in adhesion of the colored particles is a part of the lower part of the colored particles, after development, the blue (b) and red (6 ) particles are not adhered and are not left behind.

Similarly, red light will leave behind red colored particles, and blue light will leave behind blue colored particles. Therefore, if development is performed after all the O exposures for each color are completed, the corresponding particles will be left behind. Of course, in the present invention, colored particles with various other spectra can be used without being restricted to the spectral shape shown in FIG.

Therefore, it is possible to leave a plurality of corresponding particles by exposing with light of a plurality of wavelengths, and if the colored particles are sufficiently small, it is possible to display a total of eight colors including mixed colors.

With the above method, a positive image can be obtained using the additive color method, but
If yellow particles are used in place of green particles and adjacent particles are mixed with each other by exposure, development, heating and melting, etc., a positive color image can be obtained by the subtractive color method.

With the subtractive color method, many colors including black are possible, but with the additive color method, black is not possible. The use of black in the additive coloring method is limited, but it absorbs all visible light.

This can be achieved by adding black particles that transmit only infrared light. This allows black to be recorded using infrared light. Although this method is not effective for copying, it is very useful when writing with a light beam.

The above is an example of a system in which the adhesiveness of the photosensitive layer increases with light irradiation, but if a system in which the adhesiveness decreases on the contrary is used,
Negative multicolor recording becomes possible. In this case, development cannot be carried out by removing the photosensitive layer with a solvent, but by blowing off the areas where adhesiveness has decreased with compressed air or by turning one particle part downward and vibrating the paper to cause it to fall. This is possible with the left method. In this case, if the film is left in a room or the like after development, the reaction of the remaining portion will proceed due to room light, resulting in decreased adhesiveness and poor storage stability.

Therefore, in this method, a fixing step such as heating is required after development.

Colored particles can be produced by, for example, a method in which a dye is mixed during suspension polymerization of a vinyl monomer such as styrene or methyl methacrylate, or a method in which the dye is microencapsulated.

The photosensitive layer can be manufactured by mixing a photopolymerizable monomer and a dye redox polymerization initiator with a binder. By using a mixture of two or more types of dyes as a dye redox polymerization initiator, photosensitivity can be imparted over a wide range. As the dye for the visible range, common dyes such as methylene blue, rhodamine dyes, and acridine yellow can be used. As the dye for the infrared region, polymethine dye commercially available from Japan Photosensitive Color Research Institute (■) can be used.

If the amount of dye contained in the photosensitive layer is too large, a background color will remain after development, which is not preferable. therefore,
The amount of the dye is such that the optical density to is less than or equal to 1, preferably 0.0.
It is optimal to set it to 1 or less. Decreasing the amount of dye will make the background color lighter, but it will also reduce sensitivity, so it is necessary to strike a balance between the two.

When a dye that fades due to heat or ultraviolet light is used, the dye concentration can be increased by providing a color erasing step needle.

EXAMPLES The present invention will be further explained below with reference to Examples, but it is clear from the above description that the present invention is not limited thereto.

Production Example 1 Production Example 1 of Colored Fine Particles 5 occ of styrene, sec of divinylbenzene, and 52 of azobisin butyronitrile α were mixed, and added to a separately prepared 10% aqueous solution of polyvinyl alcohol (degree of polymerization 2000), while stirring thoroughly. Suspension polymerization was carried out at 80°C for 6 hours.

Thereafter, the beads were thoroughly washed with water to obtain true spherical beads with an average particle diameter of 50 μm.

An oil-soluble dye, Oil Red (color index O, 1,261) was added to a toluene-ethanol 01:1 solution.
05), Oil Blue (c, engineering).

6. 1525), oil yellow (c, ■, 1139
0), Oil Green (0, Engineering, 61565).

Red, blue, and yellow were prepared by preparing saturated solutions, soaking the beads in these for 2 hours, taking them out, washing them with ethanol, and air drying them.

Alternatively, particles colored green were obtained.

Production Example 2 Production Example 2 of Colored Fine Particles 1 ts of each of the pigments shown in Production Example 1 was added in advance to the suspension polymerization raw material solution shown in Production Example 1, and suspended under the same conditions as Production Example 1. Turbid polymerization was carried out to obtain particles colored red, blue, yellow, or green.

Example acrylamide 10? ,) Reethanolamine 0.5f
, N,N-dimethylacrylamide 1t.

Methylene blue, rhodamine B, and arysine yellow were each dissolved in 0.1 f% hydroquinone 001t1 polyvinyl alcohol (degree of polymerization 2000) 50tIII-water 50cc and applied to paper.

In a half-dried O state, red, blue, and green colored particles prepared according to Production Example 1 were sprinkled on the paper, and the paper was then tightly turned over.
Excess colored particles were removed to produce a recording medium. The above work was done in a darkroom.

The color of the obtained recording medium was light gray.

An original picture drawn in three colors of red, blue, and green was superimposed on the thus produced recording medium, and after being irradiated with a xenon lamp for 5 minutes, it was washed with water to obtain a positive image of the original picture.

As explained above, the recording medium according to the present invention is suitable for producing color copies, especially hard copies with color display, since it is possible to make color records through simple development and fixing processing.

Furthermore, by using light beams of a plurality of colors, it can also be used as a recording medium for an optically written graphic printer. In particular, this method has the advantage that full-color recording including black can be easily performed by using the recording medium according to the present invention that uses black particles that transmit infrared rays.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view schematically showing an embodiment of a multicolor recording medium of the present invention. FIG. 2 is a graph showing the relationship between wavelength and transmittance for schematically showing the transmission characteristics of the three additive primary colors. FIG. 3 is a schematic cross-sectional view schematically showing the state of the medium shown in FIG. 1 after being exposed to green light. FIG. 4 is a schematic cross-sectional view schematically showing the state of the medium shown in FIG. 3 after development. 1: Transparent colored particles 42: Photosensitive layer, 3: Substrate, 4: Photosensitive portion Patent applicant: Nippon Telegraph and Telephone Public Corporation agent Hirodai Nakamoto 2: Figure 3

Claims (1)

[Claims] 1. On a substrate, a photosensitive layer whose adhesion changes depending on irradiation light is provided as a lower layer, and a layer of a mixture of transparent dichromatic particles of two or more colors is provided on the photosensitive layer. A multicolor recording medium characterized by: 2. The multicolor recording medium according to claim 1, wherein the transparent colored particles include black particles that transmit infrared light.