JPH085252B2 - Dye for thermal transfer recording and thermal transfer sheet - Google Patents

Description

The present invention relates to a dye for thermal transfer recording and a thermal transfer sheet.

[Prior Art] Conventionally, there has been a demand for a facsimile printer, a copier, or a technique for color recording of a television image or the like, and a color recording technique using electrophotography, ink jet, thermal transfer, or the like has been studied.

The thermal transfer recording method is considered to be advantageous over other methods because the apparatus can be easily maintained and operated and the apparatus and consumables are inexpensive.

The thermal transfer system includes a base film, a base film and a transfer sheet having a heat-fusible ink layer formed thereon, which is heated by a thermal head to melt the ink and transfer-record on a recording medium. There is a sublimation method in which a transfer sheet on which an ink layer containing a sublimable dye is formed is heated by a thermal head to sublimate the dye, and transfer recording is performed on a recording medium. Since the sublimation transfer amount of the dye can be controlled by changing the applied energy, gradation recording becomes easy, which is considered to be particularly advantageous for full-color recording.

In sublimation thermal transfer recording, the sublimable dye used in the transfer sheet is very important because it greatly affects the transfer recording speed, the image quality of the recorded matter, storage stability, etc. There is a need to.

 Easily sublimate under the operating conditions of the thermal recording head.

 Do not decompose under the operating conditions of the thermal recording head.

 It should have a favorable hue for color reproduction.

 Large molecular extinction coefficient.

 Stable against heat, light, moisture, chemicals, etc.

 Easy synthesis.

 Excellent ink suitability.

Conventionally, a dye satisfying all the above conditions has not been found, and particularly a cyan dye is easily sublimated, and a dye having good hue and light resistance has not been found.

[Problems to be Solved by the Invention] An object of the present invention is to provide a cyan dye satisfying all the above conditions, and a heat-sensitive transfer sheet using the same.

[Means for Solving Problems] The present invention has the following general formula [I]. (However, in the above formula, R represents an alkyl group, a substituted alkyl group, an aralkyl group, an alkenyl group, or a cycloalkyl group.), And an anthraquinone dye represented by the formula, and a coloring material layer containing the dye on the base film. A heat-sensitive transfer sheet, which is characterized in that

The method for producing the above-mentioned dye of the present invention includes, for example, the following structural formula [II] (In the formula, R is the same as the above definition) An anthraquinone compound is obtained by reacting a cyanating agent such as sodium cyanide or potassium cyanide in an aqueous medium or an organic solvent.

Specific examples of the dye of the general formula [I] of the present invention include:
Examples include, but are not limited to, those shown in the examples.

In the above general formula [I], R is particularly preferably an allyl group, a C _{1 to} C ₈ alkyl group, a C _{7 to} C ₈ aralkyl group, a C _{3 to} C ₈ alkoxyalkyl group, or a cyclohexyl group. Dyes that can be used.

The heat-sensitive transfer sheet of the present invention is prepared by dissolving the dye of the present invention together with a binder in a medium or dispersing it in fine particles to prepare an ink, coating the ink on a base film and drying the ink to prepare a base. A color material layer is formed on the film.

As a binder for preparing the ink, cellulose-based,
Examples include water-soluble resins such as acrylic acid-based and starch-based resins, acrylic resins, methacrylic resins, polystyrene, polycarbonate, polysulfones, polyether sulfones, ethyl cellulose, acetyl cellulose, and other organic solvents or water-soluble resins. .

As a medium for ink preparation, in addition to water, alcohols such as methyl alcohol, isopropyl alcohol and isobutyl alcohol, methyl cellosolve, cellosolves such as ethyl cellosolve, aromatics such as toluene, xylene and chlorobenzene, ethyl acetate, Esters such as butyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, ketones such as cyclohexanone, methylene chloride, chloroform, chlorinated solvents such as trichloroethylene, ethers such as tetrahydrofuran and dioxane, N, N-dimethylformamide, N- Organic solvents such as methylpyrrolidone may be mentioned.

In the above ink, in addition to the above components, organic and inorganic non-sublimable fine particles, a dispersant, an antistatic agent, an antiblocking agent, an antifoaming agent, an antioxidant, a viscosity adjusting agent, etc. are added as necessary. You can also do it.

As a base film for applying the ink for making the transfer sheet, a thin film such as a condenser paper or a grasile paper, a film of a heat-resistant plastic such as polyester, polyamide, or polyimide is suitable. The range may be 3 to 50 μm.

The ink can be applied to the base film using a reverse roll coater, a gravure coater, a rod coater, an air doctor coater, etc., and the thickness of the ink coating layer is within a range of 0.1 to 5 μm after drying. So that it can be applied (Yuji Harasaki, Maki Shoten
Published in 1979 "Coating method").

[Function] Since the anthraquinone dye represented by the above general formula [I] of the present invention has a vivid cyan color, it can be combined with an appropriate yellow color and magenta color to obtain a full color record having a good dye appearance. In addition, since it is easy to sublimate and has a large molecular extinction coefficient, it is possible to obtain a recording with high color density at a high speed without imposing a heavy load on the thermal head. Further, since it is stable against heat, light, moisture, chemicals, etc., it is not thermally decomposed during transfer recording and the obtained record is excellent in storability. In particular, since the light resistance is excellent, it is possible to obtain a record having excellent storage stability which cannot be obtained when other cyan dyes are used.

The heat-sensitive transfer sheet of the present invention can use not only a thermal head but also an infrared ray, a laser beam or the like as a heating means.

[Examples] The present invention will be specifically described below with reference to Examples, but the Examples do not limit the present invention.

Example 1 a) Preparation of ink The mixture having the above composition was treated with a paint conditioner for 10 minutes to prepare an ink.

b) Preparation of transfer sheet The above ink was applied to a bar coater (RK Print Coat Instru
Condenser paper (10μm thick) using No.1 manufactured by ments
The transfer sheet was applied and dried (dry film thickness: about 1 μm).

c) Transfer recording The ink-coated surface of the above-mentioned transfer sheet was recorded under the following conditions by using the thermal head of the recording medium, and a clear cyan color was recorded for 1.20.
It was possible to obtain a record of uniform color density.

Recording conditions Linear density for main scanning and sub-scanning: 8 dots / mm Recording power: 0.25 W / dot Head heating time: 10 msec The recording medium is an aqueous dispersion of 34% by weight saturated polyester (manufactured by Toyobo Co., Ltd.). , Bayronal MD-1200,
Product name) 10g and silica (Nippon Silica Industry Co., Ltd., N
A solution prepared by mixing 1 g of ipsil E 220A (trade name) with polypropylene synthetic paper (200 μm thick) and using a bar coater (RK Prin
t Coat Instruments Co., Ltd. No. 3) and then dried.

Color density, manufactured by Macbeth, USA, Densitometer RD
It was measured using a -514 type (filter: Ratten No. 25).

The light resistance test of the obtained record was carried out using a carbon arc fade meter (manufactured by Suga Test Instruments Co., Ltd.) (black panel temperature 63 ± 2 ° C.), but almost no discoloration occurred after irradiation for 40 hours. Further, the transfer sheet and the recording were stable against heat and moisture, and had excellent storage stability in a dark place.

Example 2 The dyes shown in Table 1 were used in place of the dyes used in Example 1, and ink was prepared, a transfer sheet was prepared, and transfer recording was carried out in the same manner as in Example 1, and the results are shown in Table 1. A clear cyan color record having the indicated color density could be obtained.

 The obtained recordings were all good in light resistance.

[Effects of the Invention] As described above, by using the anthraquinone dye represented by the general formula [I] of the present invention and the heat-sensitive transfer sheet, a clear cyan image having high density,
Moreover, it is possible to form a transferred image which is stable to heat and moisture and has high light resistance.

Claims (2)

[Claims] 1. The following general formula [I] (However, in the above formula, R represents an alkyl group, a substituted alkyl group, an aralkyl group, an alkenyl group or a cycloalkyl group.). 2. The following general formula [I] is formed on a base film. (In the above formula, R represents an alkyl group, a substituted alkyl group, an aralkyl group, an alkenyl group, or a cycloalkyl group.) A heat-sensitive transfer sheet having a coloring material layer containing an anthraquinone dye.