JPH0478470B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal transfer recording method, and is particularly suitable for obtaining color images using photothermal conversion.

Conventionally, thermal transfer is a method in which a thermal transfer layer containing wax or colorant as the main ingredient, or a heat sublimation dye layer containing heat sublimation dye as the main ingredient, is provided on a thin support of 15μ or less, such as condenser paper or PET film. A method of obtaining a transfer record of a recording medium onto an image receiving sheet using a thermal head is widely used, but the transfer record of this method lacks the clarity of the record and the fastness of the record is also poor. Ta.

In addition, an infrared reflective layer that can be partially removed by electrical discharge destruction is provided on a light-transmissive sheet-like support, and a thermal transfer layer containing a photothermal conversion substance such as carbon or graphite is provided on the other side of the photothermal conversion type. Thermal transfer recording media are also used in commuter pass issuing systems.
In this case, since the photothermal conversion substance also has a function as a coloring agent, it gives good results for blackish recording, but it is not suitable for the purpose of obtaining color recording. That is, it is possible to mix and use a dye or pigment of a desired hue that has no or little photothermal conversion function with the above-mentioned photothermal conversion substance such as carbon or graphite in the thermal transfer layer, but in the case of photothermal conversion thermal transfer recording, Since the photothermal conversion substance is also transferred to the resulting thermal transfer record together with the dye or pigment of the desired color, the hue of the resulting record differs from the original hue and becomes dark and lacks brightness. In addition, a heat-sublimable dye is used as the dye of this system, a relatively heat-resistant resin is used as the binder, and the sublimation-transferred image is transferred to the image receiving sheet using the heat generated by photothermal conversion with a photothermal conversion material. A method for obtaining the following has also been proposed (Japanese Patent Application Laid-Open No. 53-5637). Furthermore, in order to obtain a color image, a heat-sublimable dye layer was provided on the back side of the zinc oxide photosensitive paper, and after development treatment with a carbon-containing toner was performed on the zinc oxide photosensitive surface using the normal Carlson method, the heat-sublimable dye layer was applied. There is also a method in which an image-receiving sheet is closely attached to the paper, and infrared rays are irradiated from the zinc oxide photosensitive paper side to raise the temperature of the toner image, and the heat is transferred to the heat-sublimable dye layer to obtain a heat-sublimation transfer image of the dye on the image-receiving sheet. Proposed. However, records obtained using this type of heat-sublimable dye have poor fastness.
Furthermore, in order to improve thermal sublimation transfer efficiency, it is effective to lower the sublimation initiation temperature of the dye used, but this greatly reduces the fastness of the resulting recording. On the other hand, in order to improve the solidity of recording, it is generally better to use a material with a high sublimation start temperature, but this is not good in terms of transfer efficiency because the energy required for sublimation increases significantly.

Furthermore, in transfer recording of sublimable dyes by applying high energy for a short time, thermal melting transfer of the sublimable dyes is likely to occur at the same time, and the resulting transfer records lack clarity and lack saturation. .

The object of the present invention is to produce clear records free of such defects by using a high-energy light source, especially a light source such as xenon light, and by photothermal conversion caused by short-term irradiation of light with excellent durability and clarity. To provide a color thermal transfer recording method that can easily obtain color transfer recording.

In the present invention, the light reflection layer of a discharge breakdown recording sheet is formed by providing a light reflection layer on a sheet-like support having a photothermal conversion function, and the light reflection layer is partially removed by discharge breakdown; A thermal transfer recording sheet comprising a thermal transfer layer containing a colorant provided on a substrate, the substrate surface and the support surface being superimposed, and then light is irradiated from above the light reflecting layer to thermally transfer the color. This objective is achieved by the thermal transfer recording method.

The present invention will be explained below with reference to the drawings. FIGS. 1 to 3 are structural diagrams of a photothermal conversion type thermal transfer recording medium comprising a discharge breakdown recording sheet and a thermal transfer recording sheet, respectively, used in the present invention. In the figure, 1 is aluminum, which can be recorded in any pattern by a conventionally widely used discharge breakdown recording device.
This is a light-reflecting layer made of a vapor-deposited film of zinc or the like. 2
is a sheet-like support that has a photothermal conversion function, and is made of film, carbon fiber paper, and resin-impregnated carbon made by kneading black pigments such as carbon and graphite that have a photothermal conversion function into relatively heat-resistant resins. Fiber paper, etc. 3 is a support or base material that is not concerned with light transmittance, and high-density paper made of natural fibers, synthetic fibers, etc., paper impregnated with tree paper, various resin films, etc. can all be used. In particular, a thinner layer is preferable, and a thickness of 15 μm or less is advantageous for the present invention because it reduces heat transfer loss. 5 is
It is a light-transparent sheet-like support, and various resin films, tracing paper, condenser paper, resin-impregnated paper, cellophane, etc. are used. Reference numeral 6 denotes a photothermal conversion layer, which is a layer made of a photothermal conversion material such as carbon, graphite, carbon fiber, black metal powder, metal oxide powder, metal sulfide powder, and a suitable binder. As a binder, polycarbonate, epoxy resin, amide resin, imide resin, polysulfone, polyphenylene, ester resin, xylene resin, silicone resin, acrylic resin, styrene resin, vinyl chloride resin, cellulose, Polyvinyl alcohol and other materials with a heat softening temperature of 120°C or higher as measured by JIS P-2531 are preferred, but even if the heat softening temperature is 120°C or lower, an appropriate curing agent or crosslinking agent may be used in combination to improve heat resistance. You can use all of them. Further, the light-to-heat conversion layer 6 may be a vapor-deposited film of a black metal, a metal oxide, or a sulfide.

7 is a sheet-like support having a photothermal conversion function, which is composed of a transparent support 5 and a photothermal conversion layer 6;
is a support having a photothermal conversion function, which is composed of a support 3 and a photothermal conversion layer 6. 4 is a thermal transfer layer, which includes ultramarine, red iron, carbon, phthalocyanine blue, benzidine yellow, carmine,
Inorganic and organic pigments and/or various dyes such as rhodamine lake, waxes such as candelilla wax, rice wax, carnauba wax, Sierra wax, montan acid wax, microcrystalline wax, paraffin wax, polyethylene wax, butyral resin, vinyl acetate resin, acrylate resin, styrene resin,
It is created by dissolving and dispersing it in thermoplastic resins such as olefin resins, alkyd resins, and rosin resins. Oil, plasticizer, non-colored pigment, etc. can be added as necessary.

4 to 7 are explanatory diagrams of recording when using the photothermal conversion type thermal transfer recording medium having the structure shown in FIG. 1. As shown in FIG. 4, first, a desired pattern is recorded on the discharge breakdown recording sheet using a conventional method, and then, as shown in FIG. 5, the discharge breakdown recording sheet and the thermal transfer recording sheet are brought into close contact with their respective supports. Then, as shown in FIG. 6, the image receiving sheet 9 and the thermal transfer layer 4 of the thermal transfer recording sheet are overlapped so that they are in close contact with each other, and a light source 10 emits high energy light such as xenon light from the discharge breakdown recording sheet side. When the light is irradiated for a short period of time, the remaining portion of the light-reflecting layer reflects the irradiated light, but in the areas that are partially removed due to discharge breakdown, the light reaches the support that has a photothermal conversion function and is converted into heat. Ru. This generated heat is transmitted to the thermal transfer layer through the base of the thermal transfer recording sheet, softens and melts the thermal transfer layer, and generates an adhesive force with the image receiving sheet, which becomes stronger than the adhesive force with the substrate. After recording in this manner, when the image-receiving sheet is separated, a thermal transfer recording of a desired hue can be obtained on the image-receiving sheet as shown in FIG. In addition, in FIGS. 4 to 7, recording is first carried out on the discharge breakdown recording sheet, but the invention is not limited to this, and the discharge breakdown recording sheet and the thermal transfer recording sheet are superimposed. Recording may be performed in stages or in a stage in which image-receiving sheets are also superimposed.

In this way, in thermal transfer recording, recording is obtained by utilizing the difference in adhesive force between the thermal transfer layer and the support during hot melting and cooling, and between the thermal transfer layer and the image receiving sheet, so material selection is important. requires careful attention.
Further, in order to prevent the spread of heat in the lateral direction and improve the clarity of recording, it is desirable that the thickness of the support having a photothermal conversion function and/or the photothermal conversion layer be thin and uniform.

In the present invention, the recorded discharge breakdown recording sheet of the photothermal conversion type thermal transfer recording medium can be used repeatedly as long as the thermal transfer recording sheet is supplied.
A desired number of copies can be obtained. Furthermore, by using thermal transfer recording sheets with different hues, it is also possible to obtain copies with different hues.

Furthermore, as input signals when recording discharge breakdown recording sheets, the original is color-separated using red, green, and blue filters, and these are recorded on three corresponding discharge breakdown recording sheets, and then the corresponding cyan, magenta, and Color copies can be made by using a thermal transfer recording sheet with a yellow thermal transfer layer and superimposing the colors on one image-receiving sheet.

Hereinafter, the present invention will be explained in more detail by showing specific examples of the present invention, but these are not intended to limit the scope of the present invention. Note that the numbers in the examples are parts by weight unless otherwise specified.

Example 1 Urethane resin (Chrisban) was coated on a 24μ film consisting of 3 parts carbon black and 97 parts polyester.
7209 (manufactured by Dainippon Ink & Chemicals Co., Ltd.) 10 parts, 1.5 parts of fine powder silica, and 87.5 parts of ethyl acetate were thoroughly mixed and dispersed, and 1 part of a crosslinking agent (Crysban NX (manufactured by Dainippon Ink & Chemicals Co., Ltd.) was added). was applied at a dry coating weight of 4 g/m ² to form a transparent roughened layer. Next, aluminum was vacuum-deposited to a thickness of 600 Å on this roughened layer to create a discharge breakdown recording sheet having a photothermal conversion function. In addition, 5 parts of phthalocyanine blue and oligostyrene (PSMS-11 manufactured by Sanko Kagaku Co., Ltd.) on 12μ capacitor paper.
A thermal transfer recording sheet was prepared by mixing and dispersing 45 parts of toluene and 50 parts of toluene using a paint conditioner (manufactured by Red.Devil Inc.) to give a dry weight of 5 g/m ² .

First, a discharge breakdown recording sheet was recorded in a pattern in accordance with an input signal using an ordinary discharge recording device at an applied voltage of 45V. Next, the thermal transfer recording sheet and the support were stacked so that they were in close contact with each other, and then the thermal transfer layer of the thermal transfer recording sheet and a high-quality paper with a basis weight of 60 g/m ² were stacked, and as in FIG. Xenon light with an energy of approximately 600 Joules (value determined from the capacitor capacity and applied voltage) was irradiated. When the high-quality paper was peeled off, a clear record of blue color was obtained on the high-quality paper.

Example 2 Aluminum was vacuum-deposited to a thickness of 800 Å on the matte-treated surface side of a 50μ polyester film that had been sandmatted on one side. Its smoothness was 70 seconds/100ml. Further, on the opposite side of the film, 10 parts of a saturated polyester resin (Byron 200 manufactured by Toyobo Co., Ltd.), 2 parts of graphite, and 38 parts of ethyl acetate were thoroughly mixed and dispersed in a stainless steel pot together with a stainless steel ball, and then a crosslinking agent (Coronate L
A discharge breakdown recording sheet having a photothermal conversion function was prepared by applying a paint containing 3 parts of Nippon Polyurethane Industries Co., Ltd.) to a dry coating amount of 4 g/m ² .

Further, a cyan thermal transfer recording sheet was prepared by applying an ink obtained by sufficiently kneading 1 part of phthalocyanine blue, 8 parts of carnauba wax, and 1 part of rice wax with a hot roll to a 9μ polyester film at a coating amount of 5 g/m ² . . A magenta thermal transfer recording sheet was prepared using rhodamine lake pigment in place of phthalocyanine blue, and a yellow thermal transfer recording sheet was prepared using benzidine yellow pigment.

First, the discharge breakdown recording sheet was recorded using the signals obtained by color-separating the original with a blue filter, and the basis weight of the yellow thermal transfer recording sheet and image receiving paper was determined.
100 g/m ² art paper was closely stacked as shown in Figure 6, and a yellow transfer image was created on the art paper using xenon flash light with an energy of 450 joules. Next, the electric discharge destruction recording sheet recorded with signals obtained by color-separating the original with a green filter, the magenta thermal transfer recording sheet, and the art paper on which the yellow transfer recording has been recorded are closely aligned and overlapped, and a xenon beam with an energy of 450 joules is placed. When color overlapping transfer was performed using flash light, a clear image with no transfer unevenness was obtained on art paper in both the overlapping color area and the magenta color single transfer area. Similarly, by combining a cyan thermal transfer recording sheet with a discharge destruction recording paper that records the original by color-separating the signal using a red filter, and further cyan transfer recording on the above-mentioned color-overlaid art paper, a clear color image is created on the art paper. was gotten. The three discharge breakdown recording sheets on which originals were separated into colors using filters were repeatedly used five times by using only new thermal transfer recording sheets, but no damage was observed.

[Brief explanation of the drawing]

Figures 1 to 3 are block diagrams of a photothermal conversion type thermal transfer recording medium used in the present invention, and Figures 4 to 7 are diagrams showing a recording process using the photothermal conversion type thermal transfer recording medium of the present invention. . 1... Light reflective layer, 2... Sheet-like support having a photothermal conversion function, 3... Support or substrate, 4...
Thermal transfer layer, 5... Transparent support, 6... Light-to-heat conversion layer, 7... Sheet-like support having a light-to-heat conversion function, 8... Sheet-like support having a light-to-heat conversion function, 9... Image receiving sheet, 10 ……light source.

Claims (1)

[Claims] 1. Partially removing the light reflecting layer of a discharge destruction recording sheet formed by disposing a light reflection layer on a sheet-like support having a photothermal conversion function by discharge destruction,
On the other hand, a thermal transfer recording sheet comprising a thermal transfer layer containing a coloring material provided on a substrate is characterized in that after the surface of the substrate and the surface of the support are superimposed, light is irradiated from above the light reflective layer to perform thermal transfer. Color thermal transfer recording method.