JPS618386A - Gradated thermal transfer recording material - Google Patents

Abstract

PURPOSE:To obtain an inexpensive a doner sheet capable of producing gradations through providing a single layer by coating by providing a heat-fusible ink layer by applying an aqueous solution and/or an aqueous emulsion comprising a colored dye or pigment, a binder and a wax as main constituents. CONSTITUTION:An aqueous solution and/or an aqueous emulsion is prepared by using a colored dye or pigment, a binder and a wax as main constituents. The heat-fuxible ink layer preferably comprises 0.5-25wt% of the dye or pigment, 0.5-50wt% of the binder and 50-90wt% of the wax. The dye or pigment comprises, for example, ones for each of yellow, magenta and cyan. A heat-fusible ink comprising the above substances is partically applied to the same base. Accordingly, even with the doner sheet provided with a single coated layer, images with high density gradations can be obtained.

Description

D) Field of Industrial Application The present invention relates to a thermal transfer recording material that exhibits gradation in a melt transfer type thermal transfer system using a thermal head.

(b) Prior art and its problems Traditionally, thermal transfer systems include a thermal sublimation transfer method in which an ink layer containing a heat sublimable dye is formed on a support, and the dye is sublimated onto the image receiving paper side by heating to perform recording. There is also known a heat-melt transfer method in which a heat-melt ink layer containing colored dyes and pigments is formed on a support (hereinafter referred to as a donor sheet), and the ink is melted and transferred to the image receiving paper side by heating for recording. . Since the thermal sublimation transfer method transfers and records the dye as a gas, the gradation of the image is good and it is seen as a promising full-color recording method, and inventions have been made to improve the dye stainability of the image-receiving paper for this system. ing. (JP-A-57-91296, JP-A-57-107885, JP-A-57-137191, JP-A-59-59495, JP-A-59-64393) However, in the thermal sublimation transfer method, the sublimation temperature of the dye is Because of the high temperature, there is a disadvantage that the heating time is long and the recording speed is slow.Also, it is possible to use dyes with low sublimation temperature, but the storage stability of the image due to re-sublimation of the dye is poor.
Furthermore, since it is a dye, the light fastness of the image is also poor. For these reasons, a lot of research has been conducted recently on methods of producing gradation using a thermal melt transfer method, which has a high recording speed and good image preservation.

For example, in JP-A-57-56295, a heat-fusible ink layer (4) is provided on a support, and on the ink layer (A), dots (4) are arranged at intervals in the form of halftone dots. ) A large number of groove-shaped heat-fusible ink layers (B) with a melting point lower than that of
The ink transfer amount is changed by heating to produce halftones.

Further, JP-A-59-64391 discloses a layer containing an image-forming substance capable of forming an image by heating, which is sequentially formed on a support.
It is coated with an image-receiving layer that can receive the image-forming material and transfer it to a transfer medium by heating, thereby controlling the amount of thermal transfer of the image-forming material to the image-receiving paper side.

These include JP-A-57-56295 and JP-A-59-643.
No. 91 all attempt to produce gradation by devising the layer structure of the ink applied to the support.

That is, the donor sheet must be completed by two coatings, which has the drawback of increasing manufacturing costs.

Furthermore, conventional single-layer donor sheets are coated with a hot-melt ink containing colored dyes, pigments, binders, waxes, and other additives by gravure or flexographic methods onto a support. Waxes are applied by being melted by heat, so the density of the coating layer is high and the conductivity of the heat given by the thermal head is good, and the ink layer corresponding to the shape of the heat-rad is almost completely dissolved. For this reason, when thermal transfer printing is performed on plain paper or coated paper using a thermal facsimile or thermal printer, even if the printing machine has a gradation of about 16 gradations, the density gradation is not good. Therefore, image 1 is recorded as a very high-contrast 0N-OFF binary value. Therefore,
In this industry, donor sheets with different transfer densities are used to print multiple times over and over to create density gradations, and in addition, area gradation methods are used to control the number of halftone dots in the printing matrix. I am trying to obtain a high gradation image using this method. This has the disadvantage that the manufacturing cost of the donor sheet is high and the printing speed is also slow.

(C) Purpose of the Invention The purpose of the present invention is to provide an inexpensive donor sheet exhibiting plJi@ properties by single layer coating.

(g) Structure and operation of the invention The present invention is a thermal transfer recording system in which a support is coated with a heat-melting ink layer, the coated surface of a thermal transfer paper and an image receiving paper are overlapped, and a thermal head performs heat-melting transfer. The heat-melting ink layer mainly contains colored dyes and pigments, binders, and waxes,
The gradation thermal transfer recording material is a gradation thermal transfer recording material in which the main component is used in the form of an aqueous solution and/or an aqueous emulsion and is coated, and preferably, the heat-melt ink layer contains 0.0 to 100% of colored dyes and pigments. 5~
25% by weight of a binder, 0.5-50% by weight of a binder, and 50-99% by weight of a wax;
This is a gradation thermal transfer recording material in which heat-melting inks containing magenta and cyan colors are partially coated on the same support.

The effect is that even with a single-layer coated donor sheet, images with high density gradation can be obtained.

The reason why the donor sheet of the present invention has density gradation is because the wax exists in the form of particles in the thermal transfer ink layer, so the amount of wax dissolved increases in proportion to the increase in energy given from the thermal head. , so the amount of transfer to the image receiving paper also increases,
It is expected that density gradations will appear as a result.

In addition to waxes, the amount of binder is also related to the increase or decrease in the amount of thermal transfer; increasing the amount of )5ingu gradually reduces the transfer density, but in this case, printing can be performed many times.

When the amount increases further, there is a tendency that thermal transfer does not occur at all. The amount of this binder, the amount and type of wax used together,
Melting point, form within the ink layer (form of particles as a continuous layer)
The present invention was completed based on the discovery that this greatly affects density gradation.

That is, waxes used in the present invention have a melting point of 50°C to 200°C, preferably 60°C to 150°C, and when the melting point is lower than 50°C, the morphology in the ink layer is However, even if it is in the form of particles, during thermal transfer,
It is difficult to obtain density gradation because the sensitivity is too high. On the other hand, if the melting point is higher than 200° C., high energy is required for heating and the amount of thermal transfer is reduced, which is not practical.

Typical examples of such waxes are shown below, but the waxes are not limited thereto.

Examples of waxes include vegetable waxes such as rice wax, wood wax, candelilla wax, and carnauba wax; animal waxes such as lanolin, beeswax, and shellac wax; and mineral waxes such as monothane wax. Synthetic waxes include paraffin wax, microcrystalline wax,
Oxidized paraffin wax, chlorinated paraffin wax,
Metallic soaps include ricinoleic acid amide, lauric acid amide, erucic acid amide, palmitic acid amide, oleic acid amide, 12-hydroxystearic acid, distearyl ketone, ethylene bisstearic acid amide, etc. Sodium stearate, sodium palmitate H1
Potassium laurate, potassium myristate, calcium stearate, zinc stearate, aluminum stearate, magnesium stearate, lead stearate, dibasic barium stearate, etc. Higher fatty acids include palmitic acid, stearic acid, etc. Higher alcohols Examples of synthetic polyalcohols include palmityl alcohol, stearyl alcohol and ceryl alcohol; and examples of synthetic polyalcohols include polyethylene glycol and polypropylene glycol.

Among these, one or two or more kinds are used in combination to adjust the final melting point to a range of 50°C to 200°C.

The image amount of these waxes in the ink layer is preferably 50 to 99% by weight; if it is less than 50% by weight, the amount of thermal transfer is too small and image density cannot be obtained, and the amount is more than 99% by weight. In this case, although the amount of thermal transfer increases, the amount of dye and pigment used is relatively reduced, so image density cannot be obtained and it is not practical.

Next, as the binder in the present invention, either a water-soluble binder or a water-insoluble binder can be used, and the water-soluble binder is used in the form of an aqueous solution, and the water-insoluble binder is used in the form of an aqueous emulsion.

Typical examples of such binders are illustrated below, but the binder is not limited to these, and two or more types may be used in combination.

Examples of the binder include polyvinyl alcohol, methylcellulose, gelatin hydroxyethylcellulose, carboxymethylcellulose, gum arabic, starch and its derivatives, casein,
Examples include polyvinylpyrrolidone, styrene-butadiene copolymer, vinyl acetate resin, vinyl acetate-based copolymer, methylmethacrylic resin, styrene-acrylonitrile resin, and ethylene-vinyl acetate copolymer.

The amount of binder used is 0.5 to 0.5% by weight in the ink layer.
50%, preferably 5 to 25% is good; if the wax used in combination has a low melting point, it is better to use a larger amount of binder, and if the wax has a high melting point, use less binder. However, sufficient gradation can be obtained. If the binder is used in an amount of i50 or more, the amount of wax transferred will be small even if the melting point of the wax is lowered, resulting in a very soft image, which is not preferable.

As the dye and pigment in the present invention, any of water-soluble dyes, oil-soluble dyes and pigments, disperse dyes, and solvent-insoluble colored pigments can be used, and they are not directly related to the quality of gradation.

Water-soluble dyes are used in the form of aqueous solutions, and oil-soluble dyes and pigments and solvent-insoluble pigments are used in the form of aqueous emulsions. It is better to form the emulsion into fine particles with a particle size of about 1 μm or less, so that the transferred image will not have roughness. Although there are sublimation dyes, the dyes of the present invention cannot fully exhibit their sublimation function. However, as long as it is used as a coloring material,
It does not interfere with the present invention and may be used without any problem. The amount of dye and pigment used is 0.5 to 25 in the heat-melting ink layer.
% by weight, preferably from 1 to 15% by weight. If it is less than 0.5% by weight, the transferred image density will be low and the image will be too soft. On the other hand, if it is more than 25% by weight, the transferred image density will be higher than necessary, which is economically wasteful, and the contrast with the background of the image will be too strong, making it undesirable.

Representative examples of dyes and pigments used in the present invention are illustrated below, but the dyes and pigments are not limited to these, and two or more types may be used in combination.

Water-soluble dyes include ketoimine (diphenylmethane) dyes, triphenylmethane dyes, xanthine dyes, acridine dyes, quinoline dyes, methine dyes, polymethine dyes, thiazole dyes,
Examples include indamine dyes, azine dyes, thiazine dyes, oxyketone dyes, anthraquinone dyes, and 7-talocyanine dyes. To give a more specific example,
As a nitroso dye, Mordant Geline 4 (C0,
10005 (hereinafter, the numbers in parentheses indicate C0 production), the azo dye is Direct Red 28 (22120), the stilbene azo dye is Direct Orange 71 (4
0205), Ketoimine dyes include Basic Yellow 2 (41000), triphenylmethane dyes include Basic Blue 1 (42025), xanthine dyes include Ashi and Dread 52 (45100), and acridine dyes include Basic Orange 23 (46075'),
Acid Yellow 2 (47010) is a quinoline dye.
, as a methine dye, Direct Yellow 59 (490
00), as azine dyes, Ashi, Dobrou 59 (5
0315), an oxazine dye such as Mordand Blue 10 (51030), a thiazine dye such as Basic Blue 9 (52015), an anthraquinone dye such as Acid Blue 45 (63010), and a phthalocyanine dye such as Direct Blue 86 (74180). .

Examples of oil-soluble dyes include azo dyes, azo metal complex dyes, anthraquinone dyes, and phthalocyanine dyes. To give more specific examples, examples of azo dyes include Solvent Yellow 2 (0, 1, 11020, hereinafter the numbers in parentheses indicate C0 processing and depth), Solvent Orange 1 (11920), Solvent Red 24 (26105), and Solvent Brown 3. (11360) etc., as azo metal complex dyes,
Solvent Yellow 19 (13900A), Solvent Orange 5 (18745A), Solvent Red 8 (12
715), Solvent Brown 37, Solvent Black 123 (12195), etc.; as an anthraquinone dye, Solvent Violet 13 (60725)
, Solvent Blue 11. (61525) and Solvent Green 3 (61565), and examples of phthalocyanine dyes include Solvent Blue 25 (74350).

Examples of disperse dyes include aminoazo or aminoanthraquinone dyes, nidroarylamine dyes, etc.

Wear. To give a more specific example, examples of aminoazo dyes include Disverse Yellow, a (C, Kogyo, 11855
, below, the numbers in parentheses indicate C0 construction, positive) Disbirds Orange 3 (11005,), 7" 4 spurs, Do 1 (1
1110), Disverse Violet 24 (1120
0), De4S Birds Blue 44, etc. The aminoanthraquinone dye is Diverse Orange 11 (6
0700), Disbird's Red 4 (6Q755), Disbird's Violet 1 (61100), and Disbird's Blue 3 (61505). Hachiis Birds Yellow 1 (1,03
45) and 42 (10338).

Colored pigments include azo pigments (monoazo, bisazo, condensed azo pigments), dye lake pigments (acid dye lake, basic dye lake, mordant dye lake pigments), nitro pigments, nitroso pigments, phthalocyanine pigments, and high-grade pigments (vat dye lake pigments). Examples include dye pigments, metal complex salt pigments, perylene pigments, isoindolino/pigments, and quinacridone pigments). To give a more specific example, an example of an azo pigment is Hansa Yellow A (C, Engineering, 11680, hereinafter the numbers in parentheses indicate C0■, P&I).
, Hansa Yellow R (12710), Pyrazolo/S, Do B
(21120), Permanent Red R (12085)
, Lake Red 0 (15585), Brilliant Carmine 6E (15850), Permanent Carmine yB (1
2490) (Monoazo pigments), Pe/Shishin Yellow (21090), Benzidine Yellow GR (21100)
, Permanent Yellow NCR (2oo4o) (the above bisazo pigment), Chromophthal Yellow, Chromophthalet (the above condensed azo pigment), and the like. Dyeing lake pigments include quinoline yellow lake (47005), eosin lake (45380), and alkali glue lake (42').
! 50A, 4-770A) (more than acid dye lake pigment)
, Rhodami/Lake B (45170), Methyl Violet Lake (42535), Victoria Blue Lake (
44045), malachite green lake (42000
) (all basic dye lake pigments), Alizarin Lake (58000) (mordant dye lake pigments), etc. Naphthol A-8 (10316) as a nitro pigment, Pigment Green B (10006) as a nitroso pigment
, naphthol green B (10020), and the phthalocyanine pigments include metal-free phthalocyanipple (741).
00), phthalocyanine blue (74160), and phthalocyanine green (74260). High-grade pigments include anthrapyrimidine yellow (6842G),
Indance Brilliant Orange GK (59305
), Indan Stremburu-Rs (69800), Thioindigo Red B (73300) (vat dye pigments)
, Nickel Azo Yellow (12775) (metal complex pigment)
, Be IJ L/Nre, Do (71140), Perylene Scarlet (71137) (all perylene pigments), Isoindolinone Yellow (isoindolino/pigment), Quinacridone Red Y (46'500), Quinacridone Magenta (73915), etc. .

In addition, as a black pigment, carbon plastic resin (0° engineering, 7
7265).

In the present invention, the main components are colored dyes and pigments, binders, and waxes as described above, but other additives such as surfactants, dispersants,
may be added. Supports include capacitor paper, typewriter paper, thin paper such as tracing paper, synthetic paper, cellophane paper, and 1cId polyester film.
Synthetic resin films such as polyimide film, polyethylene film, polycarbonate film, polystyrene film, tearless film, etc. are used as they are or are heat-resistant treated to prevent them from sticking to the thermal head. As a coating machine, a known coater such as an air knife coater, a roll coater, a blade coater, a percoater, etc. may be used, and a known printing machine such as a printing machine, a flexo method, a gravure method, etc. may also be used. In order to obtain a full-color image, at least yellow, magenta, and ink are partially printed on the same cyan support in a line-sequential, area-sequential, or dot-sequential manner. When performing partial printing with a printing machine, if the coating ink is insufficiently dry, a solvent that dries quickly and dissolves in water, such as methanol or ethanol, may be used in conjunction with the present invention. It will be carried out as long as possible.

(B) Example The present invention will be explained in more detail by way of Examples.

Example 1 In creating a gradation thermal transfer recording material (donor sheet),
As the heat-melting ink, the following materials were used: crystal violet (Cv) as a water-soluble dye, ethylene-acetate vinyl emulsion (product name: 0M-4000 manufactured by Kuraray) as a binder, and methylolamide with a melting point of 107°C as a wax, as shown in Table 1. A water-based coating with a dry weight of 4117- was applied to a 10 μm capacitor paper using a Meyer bar at the compounding ratio shown.

The ink side of the donor sheet was overlapped with plain paper (receiving paper for thermal transfer paper, manufactured by Mitsubishi Paper Mills, trade name TT'R-T), and the voltage was applied from the back side of the donor sheet at 16.0 V using a facsimile tester manufactured by Matsushita Electronic Components. Pulse width from 1.0ms to 3
．． Heated printing was performed at intervals of 0 and 0.2 milliseconds, and the density of the transferred image was measured.

For comparison, samples to which no binder was added and samples other than those of the present invention were shown.

As the results are clear from Table 1, the binder amount is 1.5
．． In the case of 1O125.50 weight percent, the original thickness density of the image increases gradually as the pulse width increases.

On the other hand, the case where the non-inventive binder is O shows a rapid rise as the pulse width increases. Also, 55
．． The one with 75 weight percent/ton shows a very slow increase, and the light pollution concentration does not appear even in a, o mi') seconds.

From the above, it is clear that those within the scope of the present invention exhibit better gradation as the pulse width increases.

Table 1 Example 2 The same experiment was carried out except that styrene-butadiene-latex was used instead of the ethylene-acetic acid emulsion as the binder in Example 1, and the optical density values of the obtained images are shown in Table 2. Ta.

The results showed the same tendency as in Example 1.

Example 3 The same experiment was conducted except that the binder and wax used in Example 1 were changed to polyvinyl alcohol and microcrystalline wax with a la point of 4°C, respectively, and the optical density values of the obtained images are shown in Table 3. .

The results showed the same tendency as in Example 1.

Table 3 The same experiment was carried out except that the binder and wax used in Example 1 were changed to polyvinyl alcohol and paraffin wax with a melting point of 60t(7), respectively, and the optical density values of the obtained images are shown in Table 4.

The results showed the same tendency as in Example 1.

Table 4 Example 5 In place of the water-soluble dye crystal violet used in Example 1, a water-insoluble cyan pigment phthalocyanine blue (c, An aqueous dispersion was prepared. 10 parts by weight (dry solid content) of this aqueous dispersion of cyan pigment, 25 parts by weight (dry solid content) an aqueous polyvinyl alcohol solution, and 65 parts by weight (dry solid content) a microcrystalline wax emulsion with a melting point of 84°C. A coating liquid was prepared by mixing the three components (solid content) and stirring until the mixture became sufficiently uniform. Using the coating liquid prepared here, a dry coating of 6 t was applied to the back side of a 12 μm PET film that had been heat-resistant treated with a Meyer bar.
/d to obtain a donor sheet. The ink side of the obtained donor sheet was overlapped with plain paper (receiver paper for thermal transfer paper, manufactured by Mitsubishi Paper Mills, trade name TTR-T), and from the back side of the donor sheet υ, Banafax b6F'-1 manufactured by Matsushita Densen ■ was applied.
When a photograph with poor gradation due to 000 was recorded as an original, clear gradation recording could be obtained.

Similarly, pernent carmine FB (0) was added to the magenta pigment.
, x, 1249G), gradation recording could be obtained using Chromo7tal Yellow 2G as the yellow pigment.

(F) Effects of the Invention The gradation thermal transfer recording material of the present invention can obtain images with extremely high gradation compared to gradation thermal transfer recording materials produced using conventional complicated coating methods, and can be easily applied to water-based coatings. It is of great industrial significance because it is inexpensive and can be applied in a single layer using a liquid.

Claims (1)

[Claims] 1. In a thermal transfer recording system in which a heat-melting ink layer is coated on a support, the coated surface of thermal transfer paper and image receiving paper are overlapped, and heat-melting transfer is performed using a thermal head. The ink layer contains colored dyes and pigments, binders, and waxes as main components, and the main components are used in the form of an aqueous solution and/or an aqueous emulsion,
A gradation thermal transfer recording material made by coating. 2. The heat-melting ink layer contains 0.5-25% by weight of colored dyes and pigments, 0.5-50% by weight of binder, and 50% by weight of waxes.
The gradation thermal transfer recording material according to claim 1, comprising 99% by weight. 3. The first claim in which the colored dye and pigment are at least yellow, magenta, and cyan, and the heat-melting ink containing these is partially coated on the same support.
The gradation thermal transfer recording material according to item 1 or 2.