JPH0596868A - Heat sensitive transfer material and forming method for picture with the same material - Google Patents

Abstract

PURPOSE:To obtain a color picture having excellent hue, high density, excellent picture stability such as fixing properties, optical resistance, etc., by providing a layer containing colorants for forming nitrogen-containing organic base and salt on a support to form a heat sensitive transfer material. CONSTITUTION:When metal sources are present in an image receiving layer 2 of an image receiving material 3 made of a support l and the layer 2, colorants in a heat sensitive transfer layer 5 of a heat sensitive transfer material 6 made of a support 4 and the layer 5 are diffused to be shifted to the material 3 by means of heat from a heat generating resistor 8 of a thermal head 7. It is reacted with the sources in the layer 2 to form a chelate colorant picture. The colorants contained in the layer 5 of the material 6 are those capable of forming salt with nitrogen-containing organic base such as azo colorant, azo methine colorant, anthraquinone colorant, etc. In order to form the salt with the organic salt while holding high sensitivity, colorant having phenolic hydroxyl group is desirable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer material and an image forming method using the thermal transfer material.
The present invention relates to a heat-sensitive transfer material having good storage stability and an image forming method using the heat-sensitive transfer material.

[0002]

2. Description of the Related Art A method using a heat-sensitive transfer material is known as a method for obtaining an image, especially a high-quality full-color image by a simple and dry process. Dyes used for forming color images are particularly important in heat-sensitive transfer materials, and various dyes for heat-sensitive transfer materials have been proposed. For example, JP-A-3-83686, 3-83687, 3-83688, 3-8
No. 3689, No. 3-114890, No. 1-228601, No. 1-229755,
No. 1-229756 and the like propose a method of forming an image by using a dye having a phenolic hydroxyl group and a dye formed by a reaction between a mordant contained in the image receiving layer and the dye.

The image formed by the dye described in the above patent has a good hue and an excellent fixing property when the dye and the mordant are completely reacted, and thus the image can be transferred by conventional thermal transfer. It has excellent properties that improve the problem. However, in thermal transfer image formation, since the image formation by heating with a thermal head or the like is carried out in a very short time, the reaction is not completed sufficiently, and undesired irregular absorption due to dichroism due to residual unreacted dye. May occur and problems such as poor fixability may occur. Further, JP-A-59-78893 and 59
-109394 and 60-2398 disclose an image forming method in which an image with a chelated dye is formed on an image receiving material by using a chelatable heat diffusible dye.

These image forming methods are also excellent as methods for improving the fixing property and the image stability such as light resistance, but the image forming methods disclosed in these patents are also effective. Since the chelation at this time is insufficient, there is a drawback that problems such as color turbidity and poor fixability due to the remaining unchelated dye occur.

In order to improve transferability, US Pat.
No. 876,236, JP-A No. 1-113275, No. 1-332952, No. 2-138
No. 6, No. 2-1387, No. 2-57322, JP-A No. 62-111784, No. 6
Although 1-286199 proposes to add an additive to the dye-donor layer, these patents do not describe that an organic base is added, and an organic base is added to the dye-donor layer to form an image-receiving layer. When transferred, the light resistance of the transferred image is significantly deteriorated, which is not preferable.

Further, in a heat-sensitive transfer material, particularly a so-called sublimation type heat-sensitive transfer material, since the dye has a thermal diffusibility, not only is there a problem in the fixability of an image, but also the storability of the heat-sensitive transfer material itself is high. There is a problem associated with diffusibility, for example, when the surface of the heat-sensitive transfer material is stored in a state of being superposed on another surface (for example, in a roll shape), the dye migrates to the other surface. These problems of storability have been solved by lowering the migration of the dye, which has a drawback that it causes a decrease in sensitivity of the thermal transfer material.

[0007]

The object of the present invention is to improve the above problems. That is, the first object of the present invention is to provide a heat-sensitive transfer material having high sensitivity and good storage stability. A second object of the present invention is to provide a heat-sensitive transfer material capable of forming a color image having a good hue and a high density and excellent fixability. A third object of the present invention is to provide an image forming method using a heat-sensitive transfer material capable of forming a color image having high density and excellent image stability such as fixability and light resistance.

[0008]

As a result of intensive studies, the present inventors have found that a heat-sensitive transfer material using a dye, particularly a dye having a good thermal diffusivity and a salt of a nitrogen-containing organic base, has a surprisingly high sensitivity and a heat-sensitive transfer. It has been found that the storability of the material is good. Moreover, when a salt of a dye and a nitrogen-containing organic base (hereinafter referred to as a dye salt) is used, the reactivity between the dye and the mordant is improved without lowering the transferability of the dye in image formation in thermal transfer. It was also found that the problems associated with the unreacted dye remaining with the mordant are improved. Furthermore, when a chelateable dye salt is used, the transferability of the dye in the image formation of thermal transfer is not deteriorated, and the reactivity with the metal ion supplying compound (hereinafter referred to as metal source) is improved, It was also found that the problems associated with the metal source and the remaining unreacted dye were improved, and the present invention was completed.

That is, the above object of the present invention is a thermal transfer material having a dye-containing layer on a support, wherein the dye forms a salt with a nitrogen-containing organic base, and a thermal transfer material containing the dye salt. An image forming method and a chelatable dye by a heat-sensitive transfer material, which is in close contact with an image receiving material having an image receiving layer containing a mordant and is heated according to image information to form an image in the image receiving layer of the image receiving material. A heat-sensitive transfer material containing a salt composed of a nitrogen-containing organic base (hereinafter referred to as a chelate dye salt) is brought into close contact with an image-receiving material having an image-receiving layer in the presence of a metal source, heated according to image information, and then in the image-receiving layer. This is achieved by an image forming method using a heat-sensitive transfer material which forms an image.

The present invention will be described in more detail below.

The dye forming the dye salt of the present invention includes:
It is not particularly limited as long as it can form a salt with a nitrogen-containing organic base, and dyes such as azo dyes, azomethine dyes, and anthraquinone dyes that have been conventionally used in heat-sensitive transfer materials (for example, Kinki Chemical Society: Functional Dye Division Material No. 16, 34 ~ 35
The dyes and their derivatives described on the page, especially the derivatives having a phenolic hydroxyl group are preferable in view of the following).

Among these dyes, a dye having a phenolic hydroxyl group is preferable in order to form a salt with a nitrogen-containing organic base while maintaining high sensitivity (high transferability of the dye).
Further, also in the case of image formation using a mordant, a dye having a phenolic hydroxyl group is preferable from the viewpoint of achieving both high transferability and mordability. As the dye having a phenolic hydroxyl group,
Derivatives having a phenolic hydroxyl group of the aforementioned dyes and JP-A-3-83686, JP-A-3-83687, JP-A-3-83688, and JP-A-3-83689
No. 3-114890, 3-90387, 3-92385, 3-92
Examples thereof include dyes described in No. 386.

Particularly preferred dyes having a phenolic hydroxyl group are the dyes represented by the general formula (I), and specific examples thereof include JP-A Nos. 3-83687, 3-83688 and 3-83.
689, 3-114890, 3-90387, 3-92385, 3
The dyes described in -92386 can be mentioned. Typical examples of the dye represented by formula (I) are shown below.

[0014]

[Chemical 3]

[0015]

[Chemical 4]

[0016]

[Chemical 5]

Next, a chelatable dye (hereinafter referred to as a chelate dye) will be described.

As the chelatable dye having a hydroxyl group, various known compounds can be appropriately selected and used. For example, JP-A-59-78893 and 60-2398.
No. 2, Japanese Patent Application No. 2-213303, No. 2-214719, No. 2-203742, etc., cyan image forming dye (simply referred to as cyan dye), magenta image forming dye (simply referred to as magenta dye) , A yellow image forming dye (simply referred to as a yellow dye), and the like.

Among the above-mentioned dyes, dyes capable of forming a tridentate chelate with at least the above metal ion-containing compound are preferable. Particularly, a dye salt is formed while maintaining high sensitivity, and good color tone and light resistance are obtained. A tridentate chelate dye having a phenolic hydroxyl group is preferred for improvement. A particularly preferred chelate dye is a dye represented by the general formula (II), and specific examples thereof include JP-A-64-365.
B-1 to B-26 described on pages 3 and 4 of No. 3 are mentioned.

[0020]

[Chemical 6]

[0021]

[Chemical 7]

[0022]

[Chemical 8]

[0023]

[Chemical 9]

The nitrogen-containing organic base forming the dye salt is preferably an organic base having a pKa of 9 or more, and examples thereof include primary to tertiary alkylamines (eg, octylamine, dibutylamine, triethylamine). Particularly preferred organic bases include compounds represented by the following general formula (III). These compounds include amidines,
Guanidine, guanidine derivatives, and vinyl-type derivatives thereof are included.

[0025]

[Chemical 10]

In the formula, R ₁ , R ₂ and R ₃ represent a hydrogen atom or an alkyl group, and R ₄ represents a hydrogen atom, an alkyl group, an aryl group, an amino group (including an alkyl-substituted amino group) or a guanidine group. .. Also, R ₁ and R ₂ and / or R ₃ and R ₄
May combine with each other to form a ring. X represents a vinyl group, and n represents 0 or 1.

Specific examples of the base represented by the above general formula (III) include B-1 described in JP-A-64-3653, pages 3 and 4.
-B-26 are mentioned.

In addition, the following organic bases are also preferable.

[0029]

[Chemical 11]

[0030]

[Chemical formula 12]

[0031]

[Chemical 13]

The dye salt of the present invention can be obtained by mixing the dye and the organic base in a suitable solvent (eg, ethyl acetate, acetone, ethanol, etc.).

The content of the dye salt in the heat-sensitive transfer material of the present invention is preferably 0.05 to 10 g per 1 m ² of the support. The dye salt-containing layer of the present invention has a binder for holding the dye salt.

As the binder, acrylic resin, methacrylic resin, polystyrene, polycarbonate, polysulfone, polyether sulfone, polyvinyl butyral,
Solvent-soluble polymers such as polyvinyl acetal, nitrocellulose and ethyl cellulose are preferred. These binders may be used not only in the form of one or two or more dissolved in an organic solvent, but also in the form of latex dispersion. The amount of binder used is 0 per 1 m ² of the support.
1 to 20 g is preferable.

The dye salt-containing layer comprises one or two of the salts of the present invention.
An ink liquid for forming a heat-sensitive transfer layer is prepared by dissolving at least one species in a solvent together with a binder, or by dispersing it in a solvent in the form of fine particles, and coating it on a support.
It can be formed by drying. The thickness of the dye-containing layer is preferably 0.1 to 10 μm as a dry film thickness.

The support is not limited as long as it has good dimensional stability and can withstand the heat of a thermal head during thermal recording, but thin paper such as condenser paper and glassine paper, polyethylene terephthalate, polyamide, polycarbonate. Such a heat resistant plastic film is preferably used. The thickness of the support is preferably 2 to 30 μm, and the support has a subbing layer made of a polymer selected for the purpose of improving the adhesiveness with a binder, transferring a dye to the support, and preventing dyeing. It is preferable to have Further, the back surface of the support (on the side opposite to the dye-containing layer) may have a slipping layer for the purpose of preventing the head from sticking to the support.

To apply the heat-sensitive transfer material of the present invention to a heat-sensitive transfer material capable of full-color image recording, a yellow heat-sensitive transfer layer containing a salt of a yellow dye and a magenta heat-sensitive transfer layer containing a salt of a magenta dye. It is preferable that a total of three cyan heat-sensitive transfer layers containing a salt of a cyan dye are successively and repeatedly coated on the same surface of the support. If necessary, a total of four heat-sensitive transfer layers containing a black image-forming substance may be sequentially and repeatedly coated on the same surface.

In the heat-sensitive transfer recording method of the present invention, the dye-containing layer of the heat-sensitive transfer material and the image-receiving layer of the image-receiving material are superposed, and then heat corresponding to image information is applied to the heat-sensitive transfer material to form a salt. The dye image is formed on the image receiving material.

The image receiving material used in the present invention has an image receiving layer on a support.

As the support of the image receiving material, paper, a plastic film, or a paper-plastic film composite can be used. Specifically, 5 of JP-A-3-54556
Examples include the supports described in line 17 on the upper right column to line 11 on the lower left column.

The image receiving layer is composed of a polymer binder. The polymer binder is preferably a thermoplastic polymer such as polyester resin, polyvinyl chloride resin, vinyl chloride and other monomers (eg vinyl acetate)
And one or more polymer layers such as a copolymer resin, polyvinyl butyral, polyvinyl pyrrolidone, and polycarbonate.

In the present invention, it is preferable to include a mordant in the image receiving layer. As a result, the dye salt reacts with the mordant to fix the image.

As a mordant, a compound having an amino group,
For example, a compound having an alkylamine (decanoylamine, octylamine, dioctylamine, trioctylamine), an arylamine (aniline derivative), a nitrogen-containing heterocyclic group (for example, a pyridine ring, an imidazole ring), the general formula (III) Examples include compounds containing the organic bases represented and quaternary ammonium salt compounds thereof.

The mordant is preferably immobilized, and a polymer mordant is particularly preferable. As the polymer mordant, JP-A-48-28325, JP-A-54-74430, JP-A-54-12472
No. 6, No. 55-22766, No. 55-142339. No. 55-23850, No.
60-23851, 60-23852, 60-23853, 60-57836
No. 60, No. 60-60643, No. 60-118834, No. 60-60643, No. 60-60643
118834, 60-122940, 60-122941, 60-12294
No. 2, No. 60-235134, U.S. Patent No. 2,484,430, No. 2,548,5
64, 3,148,061, 3,148,161, 3,309,690
No., No. 3,756,814, No. 3,898,088, No. 3,958,995,
4,115,124, 4,124,386, 4,193,800, 4,2
73,853, 4,282,305, 4,450,224, British Patent 1,
No. 594,961, No. 2,056,101, No. 2,093,041.

When the dye salt of the present invention is composed of a chelatable dye, it is preferable that the image receiving layer contains a metal source. The metal source is preferably an inorganic or organic salt of the metal and a complex of the metal. The metal ions that make up the metal source include I to I of the periodic table.
Bivalent and polyvalent metals belonging to Group VIII are mentioned,
Among them, Al, Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Sn, Ti and Zn are preferable, and Ni, Cu, Co, Cr and Zn are particularly preferable. Specific examples are Ni ²⁺ , Cu ²⁺ , Co ²⁺ , Cr ²⁺ and Zn.
A complex containing ²⁺ and represented by the following general formula is preferably used.

[0046] _{[M (Q 1) l (} Q 2) m (Q 3) n] p + p (L -) wherein, M represents a metal ion, each Q _1, Q ₂ and Q ₃ are in M It represents a coordination compound capable of coordinatively bonding with the metal ion, and these coordination compounds can be selected from, for example, the coordination compounds described in Chelate Chemistry (5) (Nankodo). Particularly preferred are ethylenediamine and its derivatives, glycinamide and its derivatives, picolinamide and its derivatives. L is an anion capable of forming a complex with counter ^{_{anion, Cl -, SO 4 -,}} C
lO ₄ ^- inorganic compound anion and benzenesulfonic acid derivatives such as, but include organic compounds anion such as an alkyl sulfonic acid derivative, particularly preferably tetraphenyl boron anion and its derivatives. l represents an integer of 1, 2 or 3, m represents 1, 2 or 0, and n represents 1 or 0, which is a tetradentate or hexadentate complex represented by the above general formula. Depending on the coordination, or Q ₁ ,
It is determined by the number of ligands of Q ₂ and Q ₃ . p is 1,
Represents 2 or 3.

The metal source is usually added to the image-receiving material, preferably the image-receiving layer of the image-receiving material or the heat-melted layer,
The amount added is 0.2 to 20 g, based on the image receiving material or heat melting layer.
/ m ² is preferable, and 1 to 10 g / m ² is more preferable.

In the heat-sensitive transfer recording method of the present invention, after the heat-sensitive transfer layer of the heat-sensitive transfer recording material and the image receiving material are superposed on each other, heat corresponding to image information is applied to the heat-sensitive transfer recording material to form a metal source and a book. An image with a chelating dye formed by reaction with an inventive dye is formed on the image receiving material. In the present invention, since the dye represented by the general formula (I) is used as a dye, a magenta image which is rich in image stability at high density and which is preferable in color reproduction can be efficiently obtained. The metal source may be present in the image receiving material,
It may be present in the heat-fusible layer provided on the heat-sensitive transfer layer. The thermal transfer recording method of the present invention will be described with reference to the drawings. In FIG. 1, when a metal source is present in the image receiving layer of the image receiving material 3 composed of the support 1 and the image receiving layer 2, the support 4 and the thermal transfer layer 5 are shown. The dye in the heat-sensitive transfer layer of the heat-sensitive transfer material 6 consisting of is diffused and transferred to the image receiving material 3 by the heat from the heating resistor 8 of the thermal head 7, and reacts with the metal source in the image receiving layer 2 to form a chelate dye image. To form. Further, in FIG. 2, when a metal source is present in the heat-meltable layer 9 provided on the heat-sensitive transfer layer 5, a heat-sensitive transfer material 10 composed of the support 4, the heat-sensitive transfer layer 5 and the heat-meltable layer 9 is formed. The dye in the heat-sensitive transfer layer 5 is diffused and transferred to the heat-fusible layer 9 by heat from the heating resistor 8 of the thermal head 7,
There it reacts with the metal source to form a chelate dye,
The heat-fusible layer containing the chelate dye is transferred to the image receiving material 11 by cohesive failure or interfacial peeling to form an image.

[0049]

The present invention will be described in more detail with reference to the following examples, but the embodiments of the present invention are not limited thereto.

Example 1 (Synthesis of Dye Salt of the Present Invention) (I-3) 7.6 g and tetramethylguanidine (TMG) 2.
5 g was mixed and stirred in acetone, the solvent was concentrated, and the solid was recrystallized from toluene to obtain a target tetramethylguanidine salt (S-1) of I-3. Table 1 by the same method
To obtain dye salts (S-2 to S-10).

(Preparation of Ink) The following raw materials were mixed to obtain an ink of a uniform solution containing the dye salt according to the present invention.

Dye salt (S-1) 4 g Polyvinyl butyral resin (BL-1, manufactured by Sekisui Chemical Co., Ltd.) 6 g Methyl ethyl ketone 200 ml (Preparation of heat-sensitive transfer material) The above ink was applied onto a polyethylene terephthalate base having a thickness of 4.5 μm by a wire bar. Was applied and dried so that the coating amount after drying would be 0.8 g / m ² , to prepare a heat-sensitive transfer material A having a heat-sensitive transfer layer formed on a polyethylene terephthalate film. In addition,
A nitrocellulose layer containing a silicon-modified urethane resin (SP-2105, manufactured by Dainichiseika) is provided as a sticking prevention layer on the back surface of the film base.

Separately, thermal transfer materials B to J having the same constitution as the thermal transfer material A were prepared except that the dye salt S-1 of the thermal transfer material A was replaced with the dye salt of the present invention shown in Table 1.

(Preparation of Image Receiving Material) On a support having polyethylene laminated on both sides of paper (a polyethylene layer on one side contains a white pigment (TiO ₂ ) and a bluing agent), an ester-modified silicone (coated) was used as an image receiving layer. An image receiving material 1 was obtained by applying a methyl ethyl ketone solution containing a polyvinyl chloride resin containing 0.15 g / m ² ) so that the coating amount of the resin was 5 g / m ² .

(Preparation of Transfer Image and Image Evaluation) The ink layers of the heat-sensitive transfer materials A to J and the image-receiving layer of the image-receiving material 1 are superposed on each other, and a heat-sensitive head is applied from the back surface of the heat-sensitive transfer material under the following recording conditions. When images were recorded, images with excellent gradation were obtained.

Recording density for main scanning and sub-scanning: 8 dots / mm Recording power: 0.6 W / dot Heating time: Adjusting the heating time stepwise between 20 and 0.2 msec. Evaluation of the obtained image (maximum density and The hue results are shown in Table 1.

[0057]

[Table 1]

TMG: Tetramethylguanidine DP
G: diphenylguanidine DBU: diazabicyclo [4.3.0] undecene PG:
Phenylguanidine Comparative Example 1 Comparison of constitutions similar to those of the thermal transfer materials A to C except that each dye alone (I-1 to 3) was added in place of the dye salt of the thermal transfer materials A to C of Example 1. Thermal transfer materials K to L were prepared. Images were prepared by using these materials in the same manner as in Example 1, but no clear hue image was obtained, and the maximum density was lower than that when the dye salt of the present invention was used. .. Further, in the comparative materials K and L, the precipitation of the dye was observed during the storage of the material, but it was not observed in the thermal transfer materials of the present invention at all.

Example 2 The surface of each of the above thermal transfer materials A to M was superposed on the back surface of the same thermal transfer material and left at 50 ° C. for 48 hours to evaluate the storability of the thermal transfer material by the degree of show-through of the dye. ..

No show-through of dye was observed in the materials A to J of the present invention, while show-through of dye was observed in the comparative materials K to M. That is, the heat-sensitive transfer material of the present invention is good in raw storability. Further, if a base that constitutes a salt is further added, the raw storability is further improved.

Example 3 To the image receiving layer of the image receiving material 1 of Example 1, the image receiving material ² to which 0.5 g / m ² of the following compound (ML-1) was added as a mordant and the polymer mordant (ML-2) below were added. The image receiving material 2 was prepared.

[0062]

[Chemical 14]

An image was formed by combining the heat-sensitive transfer material M having the same constitution as the heat-sensitive transfer material A except that the imidazole salt of I-1 was used as the dye salt, in combination with the image-receiving materials 2 and 3. The maximum density and fixability of the obtained image are shown in Table 2. The fixability was evaluated as follows.

<< Fixability >> The surface of the image receiving layer of the image and the thickness of 180
5 μm thickness on μm polyethylene terephthalate film
The coated surface of a sheet formed by coating a polyester layer having a thickness of μm was overlapped and heated at 140 ° C. for 2 minutes, and the degree of transfer of the dye from the image receiving layer to the polyester layer was visually evaluated. The less the retransfer of the dye, the better the fixability.

◯: Retransfer is not observed. Δ: Retransfer is slightly observed. X: Retransfer is remarkable.

[0066]

[Table 2]

In the case of the heat-sensitive transfer material M, when the image receiving material 1 is used, the transfer density and the fixability are deteriorated (evaluation Δ).

Example 4 (Synthesis of Chelate Dye Salt of the Present Invention) CS-1 (Salt of Dye C-1 and Amine A-1) C-1 (9.1 g) was suspended in ethyl acetate and stirred with A. -1 (2.9 g) was added. After stirring at room temperature for 30 minutes,
The precipitated crystals were collected by filtration. Yield 9.2g (79%), melting point 130
~ 135 ° C.

CS-2 (a salt of dye C-2 and amine A-1) C-2 (12 g) was suspended in 500 ml of ethyl acetate, and A-1 (2.9 g) was added with stirring. After stirring for 30 minutes at room temperature, the mixture was cooled with ice water and the precipitated crystals were collected by filtration. Yield 5.8g
(38%).

CS-3 (a salt of dye C-4 and amine A-19) C-4 (15 g) was suspended in 300 ml of acetone, and A-19 (8.6 g) was added with stirring. After stirring for 30 minutes at room temperature, the precipitated crystals were collected by filtration. Yield 8.4g (36%). CS
-4 (Dye C-9 and salt of amine A-1) C-9 (6 g) was suspended in 50 ml of ethyl acetate, and A-1 (2.5 g) was added with stirring. After stirring for 30 minutes at room temperature, the precipitated solid was collected by filtration. Yield 4.6g (52%).

CS-5 (Salt of Dye C-14 and Amine A-1) C-14 (11.32 g) was suspended in ethyl acetate, and A-1 (2.9 g) was added with stirring. After stirring for 30 minutes at room temperature, the precipitated crystals were collected by filtration. Yield 10.6 g (72%). CS
-6 (Dye C-15 and Amine A-1 salt) C-15 (8.9 g) was suspended in ethyl acetate, and A-1 (2.8 g) was added with stirring. After stirring at room temperature for 30 minutes,
The precipitated crystals were collected by filtration. Yield 9.5 g (81%).

CS-7 (Dye C-1 and a salt of amine A-4) C-1 (10.1 g) was suspended in 200 ml of ethyl acetate, and A-4 (5.8 g) was added with stirring. After heating at 50 ° C for 10 minutes, the solvent was distilled off. The precipitated solid was collected by filtration. yield
15.6g (98%).

CS-8 (Salt of Dye C-1 and Amine A-14) C-1 (8.1 g) was suspended in ethyl acetate, and A-14 (2.4 g) was added with stirring. After stirring at room temperature for 30 minutes,
The precipitated crystals were collected by filtration. Yield 9.6g (91%).

CS-9 (Salt of Dye M-2 and Amine A-1) M-2 (5 g) was suspended in 50 ml of ethyl acetate, and A-1 (2.5 g) was added with stirring. After stirring at room temperature for 30 minutes, it became candy-like. 50 ml of acetone was added and the precipitated solid was collected by filtration. Yield 4.3g (57%).

CS-10 (Salt of Dye M-4 and Amine A-1) M-4 (3 g) was suspended in 50 ml of ethyl acetate, and A-1 (1.3 g) was added with stirring. After stirring at room temperature for 30 minutes, it became candy-like. The precipitated solid was collected by filtration. Yield 3.5g
(82%).

The following synthesis was carried out in the same manner as in the above synthesis example to obtain a chelate dye salt.

CS-11 (Salt of Dye M-6 and Amine A-1) CS-12 (Salt of Dye M-8 and Amine A-1) CS-13 (Salt of Dye M-8 and Amine A-4) ) CS-14 (Salt of dye Y-1 and amine A-1) CS-15 (Salt of dye Y-4 and amine A-4) (Preparation of ink) Contains a heat diffusible dye from a mixture having the following composition A uniform ink solution was obtained.

Dye salt (CS-1) 10 g Polyvinyl acetal resin 20 g (Electrochemical butyral # 6000-C, manufactured by Denki Kagaku Kogyo Co., Ltd.) Methyl ethyl ketone 400 ml (Preparation of heat-sensitive transfer material) Applied onto the substrate with a wire bar at a coating amount of 1.0 g / m ² after drying.
Was applied and dried to form a layer containing a heat diffusible dye, thereby preparing a heat-sensitive transfer material 1 of the present invention. In addition,
On the back side of the polyethylene terephthalate film, a silicone-modified urethane resin (SP
-2105, made by Dainichiseika Co., Ltd.) is provided.

Similarly, instead of dye salt CS-1, CS-
The same thermal transfer materials 2 to 15 as the thermal transfer material 1 were prepared except that 2 to CS-15 were used. Comparative thermal transfer materials 16 to 19 similar to thermal transfer material 1 except that single dyes C-1, M-6, Y-1 and comparative dye C-0 were used in equimolar amounts instead of dye salt CS-1. Also created.

(Preparation of Image Receiving Material) Paper support having both sides of polyethylene laminated with polyethylene (a suitable amount of white pigment (TiO ₂ ) on one side of the polyethylene layer, bluing agent and the following metal sauce (approx. 5 g / m ² ). Vinyl chloride resin containing silicone oil (coating amount 0.15 g / m ² ) as an image receiving layer.
An image receiving material was prepared by coating so as to have g / m ² .

[0081] Metal _{Source: [Ni (NH 2 COCH 2} CH 2 NHC 3 H 7) 3] 2+ 2 [(C 6 H 5) 4 B -] ( creation and image evaluation transferred image) obtained thermal transfer Images were recorded by superimposing the ink application surfaces of the recording materials 1 to 18 and the image receiving layer of the above image receiving material so as to face each other, and applying a thermal head from the back surface of the thermal transfer material (recording conditions are the same as in Example 1).

Further, instead of the above-mentioned image receiving material, an image receiving material containing no metal source was prepared, and this was combined with the thermal transfer recording material.
Image recording was performed in the same manner from 19.

The maximum reflection density (Dma
x), the chelation reactivity of the dye, and the hue and fixing property of the image are evaluated according to the following criteria.

<< Fixability >> The image receiving layer surface of the image and the thickness 180
5 μm thick on polyethylene terephthalate film
A transfer sheet formed by coating a nitrocellulose layer having a thickness of μm was superposed on the coated surface and heated at 140 ° C. for 1 minute, and the degree of transfer of the dye from the image receiving layer to the nitrocellulose layer was visually evaluated. The less the retransfer of the dye, the better the fixability.

◯: No retransfer is observed Δ: Retransfer is slightly observed ×: Retransfer is remarkable << Hue >> ○: Cyan, magenta, and yellow hues are good Δ: Somewhat unfavorable hue × : Poor hue The light resistance is indicated by the residual rate (%) of the dye after irradiation of the image with a xenon fade meter for 3 days, and the sensitivity is evaluated by the reflection density when an applied energy of 6 msec is applied.

[0086]

[Table 3]

As can be seen from Table 3, the samples of the present invention have higher sensitivity and better fixability than the comparative samples, have good hue with little color turbidity due to fast chelation, and have good light resistance. Obtainable.

[0088]

[Chemical 15]

[0089]

As shown in the above examples, when the heat-sensitive transfer material of the present invention is used, a color image having a good hue and a high density can be obtained. Also, the fixability of the obtained image is excellent.
The effect of fixing property is more effective when the image receiving material contains a mordant.

All of these effects are exhibited by using a salt of a dye having a phenolic hydroxyl group and an organic base as a dye used for image formation.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an example of an image forming method using a heat-sensitive transfer material of the present invention.

FIG. 2 is an explanatory diagram showing an example of an image forming method using the heat-sensitive transfer material of the present invention.

[Explanation of symbols]

 1 image-receiving material support 2 image-receiving layer 3 image-receiving material 4 heat-sensitive transfer material support 5 heat-sensitive transfer layer 6,10 heat-sensitive transfer material 7 thermal head 8 heat-generating resistor 9 heat-melting layer 9a heat-melting property caused by cohesive failure or interfacial peeling Layer 11 Plain paper image receiving material

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tatsuo Tanaka, Konica Stock Company, Hino City, Tokyo, 1st Konica Stock Company (72) Inventor, Yoriko Nakayama 1, Kana Stock Company, Hino, Tokyo Konica Stock Company

Claims (8)

[Claims] 1. A heat-sensitive transfer material having a layer containing a dye on a support, wherein the dye forms a salt with a nitrogen-containing organic base. 2. The heat-sensitive transfer material according to claim 1, wherein the dye has a phenolic hydroxyl group. 3. The heat-sensitive transfer material according to claim 2, wherein the dye salt having a phenolic hydroxyl group is represented by the following general formula (I). [Chemical 1] Wherein, R represents a group forming a = N-C ₆ H ₄ azomethine dyes with -OH, a benzene ring may have a substituent. ] 4. The thermal transfer material according to claim 1, wherein the dye is a chelatable dye. 5. The heat-sensitive transfer material according to claim 4, wherein the chelatable dye is a tridentate chelate-forming dye. 6. A heat-sensitive transfer material, wherein the tridentate chelate-forming dye is represented by the following general formula (II). [Chemical 2] [Wherein A represents an aryl group or a heterocyclic group, and at least one of adjacent positions of carbon atoms bonded to the azo bond of the aryl group or the heterocyclic group is a chelatable hetero atom or a chelatable group]. A carbon atom substituted with a group, Z
Represents an atomic group necessary for forming a 5- or 6-membered ring. ] 7. A heat-sensitive transfer material containing a salt of a dye and a nitrogen-containing organic base on a support is brought into close contact with an image-receiving material having an image-receiving layer containing a mordant containing a nitrogen-containing compound, and heated according to image information. An image forming method using a heat-sensitive transfer material is characterized by forming an image in the image receiving layer. 8. A heat-sensitive transfer material containing a salt composed of a chelateable dye and a nitrogen-containing organic base on a support is brought into close contact with an image-receiving material having an image-receiving layer in the presence of a metal ion-providing compound, and image data is transferred according to image information. An image forming method using a heat-sensitive transfer material, which comprises heating and heating to form an image in the image receiving layer.