JP2958130B2 - Thermal transfer recording material and thermal transfer recording method using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive transfer recording material and a heat-sensitive transfer recording method using the same. The present invention relates to a novel thermal transfer recording material capable of obtaining a yellow dye image having high stability in density and a thermal transfer recording method capable of efficiently recording an image using the thermal transfer recording material.

[0002]

2. Description of the Related Art Hitherto, as a method for obtaining a color hard copy, a color recording technique using ink jet, electrophotography, thermal transfer, and the like has been studied.

Among them, the thermal transfer method has advantages such as easy operation and maintenance, downsizing of the apparatus and cost reduction, and low running cost. .

In this thermal transfer system, a transfer sheet (thermal transfer recording material) having a fusible ink layer provided on a support is used.
To transfer the ink to a transfer sheet (image receiving material) by heat-sensing the ink with a heat-sensitive head, and a heat-sensitive head to transfer a transfer sheet having an ink layer containing a heat-diffusible dye (sublimable dye) on a support. The thermal diffusion transfer method (sublimation transfer method) in which the thermal diffusion dye is transferred to the transfer-receiving sheet by heating in the heat transfer method, the change in the thermal energy of the thermal head is greater in the latter thermal diffusion transfer method This is advantageous for full-color printing because the transfer amount of the dye can be changed in accordance with the image density and the gradation of the image can be controlled.

In the thermal transfer recording of the thermal diffusion transfer system, the dye used in the thermal transfer recording material is important, and the stability of the obtained image, that is, the light fastness and the fixability are not good with the conventional one. There is a disadvantage that.

[0006] In order to improve this point, Japanese Patent Laid-Open No.
No. 8893, No. 59-109394, No. 60-239
No. 8 discloses an image forming method in which an image is formed by using a chelatable dye on an image receiving material using a chelatable heat diffusible dye.

These image forming methods are excellent methods for improving the light fastness and the fixing property. However, the yellow dyes disclosed in these publications have a small molar extinction coefficient (ε) and therefore have a high density. In order to obtain the above image, it is necessary to increase the amount of the dye to be added, and there is a problem with respect to the storability of the ink sheet (dye precipitation).

There is also a problem that sufficient fixability cannot be obtained due to low chelate reactivity.

Further, there is also a problem that the solvent solubility of the dye is low (the suitability for ink formation is poor).

[0010] The present invention has been made to improve the above circumstances.

That is, an object of the present invention is to provide a dye image having a high molar extinction coefficient (ε), a high chelate reactivity, and an excellent fixing property by using a dye having excellent suitability for ink formation. Another object of the present invention is to provide a thermal transfer recording material capable of obtaining a high-density yellow image, and a thermal transfer recording method capable of performing efficient recording using the thermal transfer recording material.

[0012]

Means for Solving the Problems The present invention according to claim 1 for achieving the above object is characterized in that a layer containing a dye represented by the following formula [I] is provided on a support. This is a heat-sensitive transfer recording material.

[0013]

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Wherein R ¹ and R ² are a hydrogen atom,
R ³ represents a cyano group,-, an alkyl group or an aryl group;
Represents CONHR ⁴ , —COCH ₃ , or —COOR ⁴ (provided that R ⁴ represents a hydrogen atom, an alkyl group, or an aryl group). X is ^{-O -, - N (-R 5} ) -, -
C (-R ⁶⁾ = represents (but, R ⁵ is a hydrogen atom,
Represents an alkyl group or an aryl group. R ⁶ represents a hydrogen atom, a halogen atom and a monovalent substituent. ). Z is 5-6 with a nitrogen atom, X and a carbon atom bonded to the azo group.
Represents the atoms necessary to form a membered aromatic heterocycle. Further, according to the present invention, there is provided a thermal transfer recording material having a layer containing the dye represented by the formula [I] according to claim 1 on a support, and an image receiving material is superimposed on the layer. The heat-sensitive transfer recording material is heated in accordance with image information, and an image is formed on the image receiving material by a chelate dye formed by a reaction between the dye and a compound that supplies a metal ion (hereinafter, may be referred to as a metal source). And a thermal transfer recording method.

Hereinafter, the compound represented by the formula [I] will be described in detail.

The alkyl group represented by R ¹ and R ² is preferably an alkyl group having 1 to 10 carbon atoms, and more preferably an alkyl group having 2 to 8 carbon atoms. Specific examples include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a t-butyl group, an n-hexyl group and a 2-ethylhexyl group. R
Examples of the aryl group represented by ¹ and R ² include a phenyl group and a naphthyl group, and preferably a phenyl group.

An alkyl group represented by R ⁴ and R ⁵ ,
Examples of the aryl group include the same groups as those described for R ¹ and R ² .

The monovalent substituent represented by R ⁶ includes an alkyl group, an aryl group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an amino group, an acylamino group, a carbamoyl group, an alkylsulfonyl group,
Examples include an arylsulfonyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a ureido group, a hydroxyl group, a cyano group, and a nitro group.

Z represents an atomic group necessary for forming a 5- to 6-membered aromatic heterocyclic ring together with a nitrogen atom, X and a carbon atom bonded to the azo group. Examples of the aromatic heterocyclic ring include pyridine, pyrimidine, pyrazine, pyridazine, pyrazole, imidazole, triazole, oxazole, isoxazole, oxadiazole, and benzerogues thereof. Among them, pyrazole, imidazole and triazole are preferred.

Each of the groups represented by R ^{1 to} R ⁵ and the ring constituted by Z may be further substituted, and the substituent may be the same as the halogen atom or the monovalent substituent represented by R ^6. Groups.

The dye represented by the formula [I] is a dye having good heat diffusibility and heat resistance, and has high solvent solubility. Importantly, these dyes react with the metal source during image formation and can be sufficiently chelated.

Typical specific examples of the dye according to the present invention are shown in Tables 1, 2 and 3.

[0023]

[Table 1]

[0024]

[Table 2]

[0025]

[Table 3]

The dye used in the present invention can be easily prepared by a diazo coupling reaction between a 6-hydroxy-2 (1H) -pyridone compound and an aromatic heterocyclic primary amine as shown in the following reaction scheme. it can. Specifically, "Chemical Reviews", 1975, 75, N
o. 2, can be produced according to the synthesis method described on pages 241 to 257.

[0027]

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The 6-hydroxy-2 (1H) -pyridone compound which is an example of the compound represented by the formula [II] is described in "Journal of Chemical Society".
25, 560 (1960) and "Anneren
According to the synthesis method described in "Der Chemie", p. 769, 1979, it can be easily produced as shown in the following reaction scheme.

[0029]

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More specifically, the compound (1) in the above scheme can be synthesized as follows. That is, a mixture of 11.3 g of the compound (1) and 12.9 g of the compound (2) is heated at 130 ° C. for 1 hour, and the produced ethanol is distilled off. After cooling to room temperature,
100 ml of methanol, 8.4 g of KOH, compound (4)
17.2 g are added and the resulting mixture is heated to reflux for 8 hours. The solvent is distilled off under reduced pressure, the obtained residue is washed with ethyl acetate, and the solid is collected by filtration. 10% of that solid
200 ml of concentrated hydrochloric acid, then 300 ml of ethyl acetate
Extract with ml. By distilling off the solvent, 26.5 g (yield 90%) of compound (5) can be obtained.

Next, 2-amino-4-methylpyrazole
2 g is dissolved in 50 ml of acetic acid, and a diazonium salt solution is prepared by adding a nitrosyl sulfate solution prepared from 3.7 g of sodium nitrite and 30 ml of (CH ₃ ) ₂ SO ₄ at an internal temperature of 20 ° C. or lower. Compound (5)
To a solution obtained by dissolving 14.6 g and 75 g of triethylamine in 300 ml of methanol is added the above diazonium salt solution at an internal temperature of 20 ° C. or lower. After completion of addition, pure water 1
One liter was added, neutralized with sodium acetate, and the precipitated crystals were collected by filtration, washed with water and dried. This was recrystallized from methanol to give Exemplified Compound (Y-2) 15.0.
g (yield 75%).

The above synthesis example is one example. Therefore, in the present invention, the synthesis of the compound represented by the formula [I] is not limited to the compound used in the synthesis example, the amount used for the reaction, the reaction procedure, and the like.

The thermal transfer recording material used in the present invention is:
A layer containing the dye represented by the formula [I] (hereinafter sometimes referred to as a thermosensitive layer) is provided on a support.

The content of the dye in the heat-sensitive layer is preferably from 0.1 g to 10 g per 1 m ² of the support.

The heat-sensitive layer is formed by dissolving one or more of the above-mentioned dyes together with a binder in a solvent, or by dispersing the dye in the form of fine particles in a solvent, or by a hot melt method. It can be formed by preparing, applying the coating material on a support, and drying it appropriately.

The thickness of the heat-sensitive layer is 0.1 μm to 5 as a dry film thickness.
μm is preferred.

As the binder, cellulosic,
Water-soluble polymers such as polyacrylic acid, polyvinyl alcohol, and polyvinylpyrrolidone, acrylic resin, methacrylic resin, polystyrene, polycarbonate, polysulfone, polyethersulfone, polyvinyl butyral, polyvinyl acetal, nitrocellulose, and ethylcellulose can be exemplified. .

These binders may be used not only by dissolving one kind or two or more kinds in an organic solvent, but also in the form of a latex dispersion.

The amount of the binder used is 1 m
0.1 g to 50 g per ² is preferred.

Examples of the solvent include water, alcohols (eg, ethanol and propanol), cellosolves (eg, ethyl acetate), aromatics (eg, toluene, xylene, chlorobenzene), ketones (eg, acetone, methyl ethyl ketone), and ethers. (Eg, tetrahydrofuran, dioxane), chlorinated solvents (eg, chloroform, trichloroethylene) and the like.

As the support, a dimensional stability method is preferred.
There is no particular limitation as long as it can withstand the heat of the thermal head during recording, but thin paper such as condenser paper and glassine paper, and heat-resistant plastic films such as polyethylene terephthalate, polyamide, and polycarbonate are preferably used.

The thickness of the support is preferably from 2 to 30 μm. The support is provided with a subbing layer for the purpose of improving the adhesiveness with a binder and preventing transfer and dyeing of the dye to the support. Is also good.

Further, a slipping layer for preventing the thermal head from sticking to the support may be provided on the back surface of the support (the side opposite to the heat-sensitive layer).

In the heat-sensitive transfer recording material of the present invention, a heat-fusible layer containing a heat-fusible compound as described in JP-A-59-106997 may be provided on the heat-sensitive layer.

As the above-mentioned heat-fusible compound, 65 to 13
A colorless or white compound having a melting point of 0 ° C. is preferably used. Examples of the heat-fusible compound include waxes such as carnauba wax, beeswax, candelilla wax, higher fatty acids such as stearic acid and behenic acid, alcohols such as xylitol, amides such as acetamide and benzoamide, phenylurea, diethylurea and the like. And the like. In addition, these heat-meltable layers include
In order to enhance the retention of the dye, for example, a polymer such as polyvinylpyrrolidone, polyvinylbutyral, and saturated polyester may be contained.

The thermal transfer recording material of the present invention can obtain a yellow dye image from one kind of dye. However, when applied to full-color image recording, a cyan heat-sensitive layer containing a cyan dye and a magenta dye containing a magenta dye are used. It is preferable that at least three layers of the thermosensitive layer and the yellow thermosensitive layer containing the yellow dye according to the present invention are sequentially and repeatedly applied on the same surface of the support.

If necessary, a thermosensitive layer containing a black image forming substance in addition to a yellow thermosensitive layer containing the dye according to the present invention, a magenta thermosensitive layer, and a cyan thermosensitive layer are sequentially and repeatedly provided on the same surface of the support. You may.

In the image forming method of the present invention, the heat-sensitive layer of the heat-sensitive transfer recording material is overlaid on the gift-receiving material, heat is applied to the heat-sensitive transfer recording material according to the image information, and the metal source and the dye in the heat-sensitive layer are removed. The image is formed on the image receiving material by the chelate dye formed by the reaction of

In this case, in the present invention, since the dye represented by the formula [I] is used as the dye, an image having high density and high stability can be efficiently obtained.

The metal source may be present in the image receiving material or may be present in the heat-meltable layer provided on the surface of the heat-sensitive layer.

The image forming method of the present invention will be described with reference to the drawings. In FIG. 1, when a metal source is present in an image receiving layer 2 of an image receiving material 3 comprising a support 1 and an image receiving layer 2,
The dye in the heat-sensitive layer 5 of the heat-sensitive transfer recording material 6 composed of the support 4 and the heat-sensitive layer 5 is diffused and transferred to the image receiving material 3 by, for example, heat from the heating resistor 8 of the thermal head 7.
In the image receiving layer 2, it reacts with the metal source to form a chelate dye. In FIG. 2, when a metal source is present in a heat-meltable layer 9 provided on the surface of the heat-sensitive layer 5, a heat-sensitive transfer recording material 10 comprising the support 4, the heat-sensitive layer 5 and the heat-meltable layer 9 is formed. The dye in the heat-sensitive layer 5 is diffused and transferred to the heat-meltable layer 9 by, for example, heat from the heating resistor 8 of the thermal head 7, where it reacts with the metal source to form a chelate dye. Is transferred to the image receiving material 11 by cohesive failure or interfacial peeling, or the dye in the heat sensitive layer is diffused and transferred to the heat fusible layer after the heat fusible layer is transferred to the image receiving material 11. Then, it reacts with the metal source to form a chelate dye.

Although a heating method or heating by a thermal head is generally used, electric heating or heating using a laser may be used.

Examples of the metal ion constituting the metal source include divalent and polyvalent metal ions belonging to Groups I to VIII of the periodic table. Among them, Al, Co,
Cr, Cu, Fe, Mg, Mn, Mo, Ni, Sn, T
i and Zn ions are preferred, especially Ni, Cu, C
The ions of r, Co and Zn are preferred.

Examples of the compound for supplying these metal ions (ie, metal source) include inorganic or organic salts of the metal and complexes of the metal, and salts and complexes of organic acids are preferable.

Specific examples include Ni ²⁺ , Cu ²⁺ , Cr
Salts of lower fatty acids of ²⁺ , Co ²⁺ and Zn ²⁺ with acetic acid, etc.
Salts of higher fatty acids such as stearic acid, and salts of aromatic carboxylic acids such as benzoic acid and salicylic acid are exemplified.

Further, a complex represented by the following formula can also be preferably used. [M (Q ¹ ) _k (Q ² ) _m (Q ³ ) _n ] ^{p +} (Y ⁻ ) _{p In} the above formula, M represents a metal ion, preferably Ni ²⁺ , Cu ²⁺ , Cr ^2+. , Co ²⁺ , Zn ^{2+ and the} like.

Q ¹ , Q ² and Q ³ each represent a coordination compound capable of coordinating with the metal ion represented by M, and may be the same or different.

These coordination compounds include, for example, the coordination compounds described in Chelate Chemistry (5) (Nankodo).

Y represents an organic anion, and specific examples include a tetraphenylboron anion and an alkylbenzenesulfonic acid anion.

K represents 1, 2 or 3, and m represents 1, 2
Or 0, and n represents 1 or 0, which is determined depending on whether the complex represented by the above formula is tetradentate or hexadentate, or coordination of Q ¹ , Q ² , Q ³ Determined by the number of children.

P represents 1 or 2, preferably 2
It is. When p is 2, the coordination groups of the coordination compounds represented by Q ¹ , Q ² and Q ³ are not anionized.

[0062] The addition amount of the metal source is usually provided to the image-receiving material or thermofusible layer, preferably ^{0.2~20g / m 2, 1~10g / m} 2 is more preferable.

The image receiving material used in the present invention is generally used as an image receiving layer on a support made of paper, plastic film, or paper-plastic film composite, as a polyester resin, polyvinyl chloride resin, vinyl chloride and other monomers. (E.g., vinyl acetate, etc.)
One or two or more polymer layers such as polyvinyl butyral, polyvinyl pyrrolidone and polycarbonate are formed.

Further, the support itself may be used as an image receiving material.

[0065]

EXAMPLES Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto.

(Example 1) -Preparation of ink liquid- An ink liquid in a uniform solution state was obtained having (Exemplary Compound No. Y-2) and the following binder and solvent.

Dye (Exemplified Compound No. Y-2) 10 g Nitrocellulose resin 10 g Methyl ethyl ketone · · · · · · · 300 ml - thermal transfer Preparation of a recording material - the coating material, the coating amount after drying is 0.8 g / m ² using a wire bar to a thickness 4.5μm polyethylene terephthalate film The coating was dried as described above to prepare a heat-sensitive transfer recording material having a heat-sensitive layer formed on a polyethylene terephthalate film.

On the back surface of the polyethylene terephthalate film, a nitrocellulose layer containing a silicon-modified urethane resin [SP-2105, manufactured by Dainichi Seika Co., Ltd.] is provided as a slipping layer.

-Preparation of Image-Receiving Material- An image-receiving layer of 0.15 g / m ² was formed on a polyethylene layer [containing a white pigment (TiO ₂ ) and a bluing agent] on one side of a paper laminated with polyethylene on both sides. And a vinyl chloride resin containing 5 g / m ^{2 of the following} metal source was applied so as to have a coating weight of 10 g / m ² to obtain an image receiving material.

[0070] Metal source ^{_{[Ni 2+ (NH 2 CH 2}} CONH 2) 3] {(C 6 H 5) 4 B -} 2 - thermal transfer recording method - and the K thermal transfer image receiving material and the thermal transfer recording material An image was recorded under the following recording conditions by superposing the heat-sensitive layer surface of the recording material and the image-receiving surface of the image-receiving material so as to face each other, and applying a heat-sensitive head from the back side of the heat-sensitive transfer recording material.

As a result, a yellow image having excellent gradation was obtained.

Table 4 shows the results of evaluation of the maximum density (D _max ), chelation reactivity, and fixability of this image in the following manner. Table 4 shows the molar extinction coefficient of each dye in the acetone solution during chelate formation.

Line density of main scanning and sub-scanning: 8 dots / mm Recording power: 0.6 W / dot Heating time of thermal head: 15 msec to 0.2 msec
The heating time was adjusted stepwise between steps c and c. Evaluation of chelation reactivity: ：: almost fully formed chelate dye image △: insufficient formation of chelate dye ×: formation of chelate dye only in part of dye Fixability: surface of image receiving layer of obtained image And the surface of the image receiving layer of the image receiving material on which no image is formed, and
After heating at 40 ° C. for 2 minutes, the degree of transfer of the dye to the image receiving layer surface of the image receiving material on which no image was formed was visually observed to evaluate the fixability. ：: No dye transfer was observed. Δ: Transfer of the dye was slightly observed. X: Dye transfer is remarkable.

(Examples 2 to 10)
The thermal transfer recording materials 2 to 10 described in Example 1 were prepared, except that the dyes were replaced with the following dyes. The dye used in these recording materials was a solvent (methyl ethyl ketone) in the same manner as the dye used in recording material-1 (exemplary dye-2).
There was no problem with the solubility in the ink, and the suitability for ink formation was good.

Using the recording materials 2 to 10 obtained, image recording and image evaluation were performed in the same manner as in Example 1.

(Comparative Examples 1 to 3) Thermal transfer recording material 1 except that the dye of Example 1 was changed to the following comparative dyes, A, B and C:
Comparative thermal transfer recording materials 1, 2 and 3 were prepared. However, Comparative Dye-C had low solubility in the solvent, and became an ink liquid in which part of the dye was insoluble.

[0077]

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[0078]

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[0079]

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[0080]

[Table 4]

As is evident from Table 4, the image obtained by the present invention has a high maximum density and is excellent in chelate reactivity and fixability. The dye of the present invention is a comparative dye A,
It was also found to have a higher molar extinction coefficient (ε) than B.

In Comparative Examples 1 and 2, since the molar extinction coefficient (ε) of the dye was low, the maximum concentration was lower than that of the present invention.
It was found that the chelate reactivity and fixability were poor, and that Comparative Example 3 had a low maximum concentration and was extremely poor in chelate reactivity and fixability due to the low solvent solubility of the dye.

(Example 11) On the polyethylene terephthalate film used as a support in Example 1, a heat-sensitive layer containing the dye according to the present invention (Exemplified Compound No. Y-2) was prepared.
A heat-sensitive transfer recording material was prepared by sequentially applying a heat-sensitive layer containing a cyan dye having the following structure and a heat-sensitive layer containing a magenta dye having the following structure.

[0084]

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[0085]

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The binder used in each heat-sensitive layer was the same as in Example 1. The amounts of the pigment and the binder were the same as in Example 1.

Next, a video printer (manufactured by Co., Ltd.) using the above-described thermal transfer recording material and the same image receiving material as in Example 1.
When a full-color image was created by Hitachi, Ltd., VY-100), a full-color image showing good color reproducibility was obtained.

The fixing property and image stability of this image were both good.

(Example 12) 100 ml of an aqueous solution containing 5 g of a ball mill dispersion of P-triamide, 7 g of polyvinylpyrrolidone, 3 g of gelatin and 0.3 g of the following hardener was applied as an intermediate layer on the thermal transfer recording material of Example 10. -Toluamide was applied so that the coating amount was 0.5 g / m ² .

[0090]

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Further, on the intermediate layer, the same metal source (a coating weight of 1.0 g / m ² ) as used in Example 1, the following ultraviolet ray inhibitor (a coating weight of 0.1 g / m ² ), and the following oxidation Inhibitor (weight 0.1 g / m ² ) and ethylene-vinyl acetate copolymer (vinyl acetate content 20% by weight, weight 0.2 g / m ² )
carnauba wax comprising m ²⁾ to (IX amount 2.0 g / m ²⁾ and Coating by hot melt coating to obtain a thermal transfer recording material having a heat-fusible layer.

Using this heat-sensitive transfer material and the image receiving material, full-color image recording was performed by a video printer in the same manner as in Example 10.

The image receiving material used was plain white paper.

The obtained image had good fixability and image stability.

[0095]

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[0096]

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[0097]

As described in detail above, according to the present invention, it is possible to efficiently use a heat-sensitive transfer recording material capable of obtaining a yellow dye image having improved heat resistance and light resistance, as well as improved chelateability and fixability. An image forming method capable of recording can be provided.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an image forming method using a thermal transfer recording material of the present invention.

FIG. 2 is an explanatory diagram of an image forming method using the thermal transfer recording material of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Support 2 Image receiving layer 3 Image receiving material 4 Support 5 Thermal layer 6 Thermal transfer recording material 7 Thermal head 8 Heating resistor 9 Thermal fusible layer 10 Thermal transfer recording material 11 Plain paper image receiving material 12 Paper 13a, 13b Polyethylene layer 14 Polyvinyl chloride layer

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-61-262191 (JP, A) JP-A-50-112572 (JP, A) JP-A-60-152563 (JP, A) 290583 (JP, A) JP-A-2-243395 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B41M 5/38 CA (STN) REGISTRY (STN)

Claims (2)

(57) [Claims] 1. A heat-sensitive transfer recording material having a layer containing a dye represented by the following formula [I] on a support. Embedded image Wherein R ¹ and R ² represent a hydrogen atom, an alkyl group,
R ³ represents a cyano group, —CONH
R ⁴ , —COCH ₃ , or —COOR ⁴ (however,
R ⁴ represents a hydrogen atom, an alkyl group or an aryl group. ). X is ^{-O -, - N (-R 5} ) -, - C (-R
⁶ ) = (where R ⁵ represents a hydrogen atom, an alkyl group, or an aryl group; R ⁶ represents a hydrogen atom, a halogen atom and a monovalent substituent). Z represents a group of atoms necessary for forming a 5- to 6-membered aromatic heterocyclic ring together with a nitrogen atom, X and a carbon atom bonded to the azo group. ] 2. An image receiving material is superimposed on said layer of a thermal transfer recording material having a layer containing the dye represented by the formula [I] according to claim 1 on a support, and said thermal transfer recording material is converted into image information. A heat transfer recording method, wherein an image is formed on an image receiving material by a chelate dye formed by a reaction between the dye and a compound supplying a metal ion.