JP2949828B2 - Thermal transfer recording material and image forming method using the recording material - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer recording material and an image forming method using the recording material, and more particularly, to a yellow dye excellent in spectral characteristics, heat resistance and fixability. The present invention relates to a novel thermal transfer recording material from which an image can be obtained, and an image forming method capable of efficiently recording using the thermal transfer recording material.

[Prior Art] Conventionally, as a method of obtaining a color hard copy, a color recording technique by ink jet, electrophotography, thermal transfer, or the like has been studied.

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

In the thermal transfer method, a transfer sheet (thermal transfer recording material) having a fusible ink layer provided on a support is heated by a thermal head, and the ink is melt-transferred onto a transfer-receiving sheet (image receiving material). And a transfer sheet having an ink layer containing a heat-diffusible dye (sublimable dye) on a support by a thermal head to transfer the heat-diffusible dye to a transfer sheet (sublimation transfer method (sublimation)). Transfer method), but the latter thermal diffusion transfer method can control the gradation of the image by changing the transfer amount of the dye according to the change in the thermal energy of the thermal head. This is advantageous for full-color recording.

In thermal transfer recording of the thermal diffusion transfer method, the dye used in the thermal transfer recording material is important, and the conventional one has a disadvantage that the stability of the obtained image, that is, the light resistance and the fixing property are not good. Was.

To improve the point, Japanese Patent Application Laid-Open Nos. Sho 59-78893 and 59
JP-A-109394 and JP-A-60-2398 disclose image forming methods in which an image is formed by using a chelatable dye on an image receiving material using a chelatable heat-diffusible dye.

[Problems to be Solved by the Invention] According to these image forming methods, light fastness and fixability can be improved, but various problems still remain. That is, the yellow dye described in the above publication used for the thermal transfer recording material is not always satisfactory in terms of dye diffusibility, chelating property and hue, and further improvement has been desired.

The present invention has been made to solve the above problems, and an object of the present invention is to provide not only heat resistance, light resistance, and fixability but also heat diffusion, chelation, and hue (undesirable absorption is small, An object of the present invention is to provide a heat-sensitive transfer recording material capable of obtaining a yellow dye image with improved dye image, and an image forming method capable of efficiently recording using the heat-sensitive transfer recording material.

[Means for Solving the Problems] The above object of the present invention is achieved by a heat-sensitive transfer recording material characterized by having a layer containing a yellow dye represented by the following general formula [I] on a support. .

[Wherein, R ¹ and R ² each represent a hydrogen atom or a substituent, and Z represents a pyrazole ring, an imidazole ring, a benzopyrazole ring, or a benzo group together with a carbon atom bonded to an azo group and a nitrogen atom bonded to the carbon atom. It represents an atomic group necessary for forming an imidazole ring, a triazole ring or a tetrazole ring. Further, the object of the present invention is to superpose an image receiving material on a heat-sensitive transfer recording material having a layer containing a yellow dye represented by the general formula [I] on a support, and apply the heat-sensitive transfer recording material according to image information. And heating to form an image on an image receiving material using a chelate dye formed by a reaction between the yellow dye and a metal ion.

 Hereinafter, the present invention will be described in more detail.

R ¹ and R ² in the general formula [I] each represent a hydrogen atom or a substituent, and examples of the substituent include a halogen atom (a chlorine atom, a bromine atom, etc.),
To 12 alkyl groups such as methyl, ethyl, butyl, isopropyl, hydroxyethyl, methoxyethyl, cyanoethyl, trifluoromethyl, etc.),
A cycloalkyl group (eg, a cyclopentyl group, a cyclohexyl group, etc.), an alkoxy group (an alkoxy group having 1 to 12 carbon atoms, eg, a methoxy group, an ethoxy group, an isopropoxy group, a methoxyethoxy group, a hydroxyethoxy group, etc.), an aryl group ( For example, a phenyl group, a p-tolyl group,
p-methoxyphenyl group, p-chlorophenyl group, o-
A methoxyphenyl group, an aryloxy group (for example, a phenoxy group, a p-methylphenoxy group, a p-methoxyphenyl group, an o-methoxyphenoxy group, etc.), an aralkyl group (a benzyl group, a 2-phenethyl group, etc.), a cyano group, Acylamino group (acetylamino group, propionylamino group, isobutylylamino group, etc.), sulfonylamino group (methanesulfonylamino group, benzenesulfonylamino group, trifluoromethanesulfonylamino group, etc.), ureido group (3-methylureido group, 3 , 3-dimethylureido group, 1,3-dimethylureide group, etc., alkylthio group (methylthio group, butylthio group, etc.), arylthio group (phenylthio group, p-tolylthio group, etc.), alkoxycarbonyl group (methoxycarbonyl group, ethoxy group, etc.) Carbonyl group), carbamo Le group (methylcarbamoyl group,
Dimethylcarbamoyl group, etc.), sulfamoyl group (dimethylsulfamoyl group, diethylsulfamoyl group, etc.), sulfonyl group (methanesulfonyl group, butanesulfonyl group, phenylsulfonyl group, etc.), acyl group (acetyl group, butyroyl group, etc.) And an amino group (eg, a methylamino group, a dimethylamino group, an anilino group) and the like.

When R ¹ represents a substituent, preferred among these are alkyl groups having 8 or less carbon atoms, and when R ² represents a substituent, preferred among these are aryl groups having 10 or less carbon atoms. is there. The pyrazole ring, imidazole ring, benzpyrazole ring, triazole ring or tetrazole ring formed by Z may have a substituent, and the substituent is shown when R ¹ or R ² represents a substituent. The same substituents can be mentioned.

 The above dye is a yellow dye excellent in heat diffusibility.

The representative compounds of the yellow dye represented by the general formula [I] which are preferably used in the invention are shown below.

The yellow dye used in the present invention can be easily produced by diazo coupling of a 5-pyrazolone compound with a heterocyclic primary amine as shown in the following scheme. Specifically, Chemical Reviews, 1975, Vol. 75
It can be produced according to the synthesis method described in No. 2, pp. 241 to 257.

Synthesis Example (Synthesis of Exemplified Compound No. Y-8) Nitrosylsulfuric acid solution prepared from 1.6 g of sodium nitrite and 10 ml of sulfuric acid was cooled to 20 ° C. or less. A solution of 2.0 g of 3-amino-5-methylpyrazole in acetic acid (20 ml) Was added slowly. After the addition, 20 ml of ice water was added to obtain a uniform solution. This solution was added to a solution prepared by dissolving 1.8 g of 3-t-butyl-5-pyrazolone and 10.4 g of triethylamine in 30 ml of methanol.
Added below ℃. After the addition, 300 ml of ice water was added, the mixture was neutralized with sodium acetate, and the precipitated crystals were collected by filtration, washed with water and dried. Then, the product was recrystallized from methanol to obtain 2.3 g of a yellow dye (Exemplary Compound No. Y-8).

The heat-sensitive transfer recording material of the present invention is provided with a layer containing the yellow dye represented by the above general formula [I] (hereinafter sometimes referred to as a heat-sensitive layer) on a support.

The content of the yellow dye in the heat-sensitive layer depends on the support.
0.1 g to ²⁰ g per m ² is preferred.

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

The thickness of the heat-sensitive layer is preferably from 0.1 μm to 5 μm in dry film thickness.

As the binder, cellulose-based, polyacrylic acid-based, polyvinyl alcohol-based, polyvinylpyrrolidone-based water-soluble polymer, acrylic resin, methacrylic resin, polystyrene, polycarbonate, polysulfone,
Examples thereof include polyether sulfone, polyvinyl butyral, polyvinyl acetal, nitrocellulose, and ethyl cellulose.

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, the support 1 m ² per 0.1g~5
0 g is preferred.

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

The support is not particularly limited as long as it has good dimensional stability and can withstand the heat of the thermal head during recording.Condenser paper, thin paper such as glassine paper, polyethylene terephthalate, polyamide, polycarbonate, etc. A heat-resistant plastic film or the like is preferably used.

The thickness of the support is preferably from 2 to 30 μm, and the support may be provided with an undercoat layer for the purpose of improving the adhesiveness with a binder and preventing transfer and dyeing of the dye to the support.

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

The heat-sensitive transfer recording material of the present invention is provided on the heat-sensitive layer in JP-A-59-1984.
A heat-fusible layer containing a heat-fusible compound as described in JP-A-106997 may be provided.

As the heat-fusible compound, a colorless or white compound having a melting point of 65 to 130 ° C. is preferably used, for example, carnauba wax, beeswax, waxes such as candeli wax, stearic acid, higher fatty acids such as behenic acid, Examples include alcohols such as xylitol, amides such as acetamide and benzamide, and ureas such as phenylurea and diethylurea.

In addition, these heat-meltable layers may contain a polymer such as polyvinylpyrrolidone, polyvinylbutyral, and saturated polyester in order to enhance the retention of the dye.

The heat-sensitive transfer recording material of the present invention can obtain a yellow dye image from a kind of yellow dye, but when applied to full-color image recording, a cyan heat-sensitive layer containing a cyan dye and a magenta heat-sensitive layer containing a magenta dye It is preferable that at least three layers of 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.

Further, if necessary, a yellow heat-sensitive layer containing a yellow dye according to the present invention, a magenta heat-sensitive layer, a heat-sensitive layer containing a black image-forming substance in addition to the cyan heat-sensitive layer may be sequentially and repeatedly provided on the same surface of the support. Good.

In the image forming method of the present invention, the heat-sensitive layer of the heat-sensitive transfer recording material is superimposed on the image-receiving material, heat is applied to the heat-sensitive transfer recording material in accordance with image information, and the metal ions react with the dye in the heat-sensitive layer. Depending on the chelate dye formed,
An image is formed on the image receiving material.

The metal ions may be present in the image receiving material,
It may be present in a 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. First
In the drawing, when metal ions are present in the image receiving layer 2 of the image receiving material 3 composed of the support 1 and the image receiving layer 2, the above-mentioned heat transfer layer 6 in the heat-sensitive transfer recording material 6 composed of the support 4 and the heat-sensitive layer 5 is used. The yellow dye diffuses and transfers to the image receiving material 3 due to, for example, heat from the heating resistor 8 of the thermal head 7 and reacts with the metal ions in the image receiving layer 2 to form a chelate dye.

In FIG. 2, when the metal ions were present in the heat-meltable layer 9 provided on the surface of the heat-sensitive layer 5, the heat-sensitive transfer recording comprising the support 4, the heat-sensitive layer 5, and the heat-meltable layer 9 was performed. The dye in the heat-sensitive layer 5 of the material 10 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 ions to form a chelate dye. After the heat-fusible substance 9a containing a chelate dye migrates to the image receiving material 3 by cohesive failure or interfacial separation, or after the heat-meltable layer migrates to the image receiving material 11 such as plain paper, the dye in the heat-sensitive layer It diffuses into the fusible layer where it reacts with the metal ions to form a chelating dye.

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

Examples of the metal ion include divalent and polyvalent metal ions belonging to Groups I to VIII of the periodic table.
Among them, ions of Al, Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Sn, Ti and Zn are preferable, and ions of Ni, Cu, Cr, Co and Zn are particularly preferable.

Examples of the compound that supplies these metal ions (hereinafter, sometimes referred to as a metal source) include an inorganic or organic salt of the metal and a complex of the metal, and among them, an organic acid salt and a complex are preferable.

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

Further, a complex represented by the following general formula can also be preferably used.

[M (Q ¹ ) ₁ (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⁺ .

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 from each other.

Examples of these coordination compounds include the coordination compounds described in Chelate Chemistry (5) (Nankodo).

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

l represents an integer of 1, 2 or 3, m represents 1, 2 or 0, and n represents 1 or 0, and these represent a tetradentate or hexadentate complex represented by the above general formula. Or the number of ligands of Q ¹ , Q ² , Q ³ .

 p represents 1 or 2, but is preferably 2.

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

The addition amount of the metal source is usually 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 a polyethylene resin, a polyvinyl chloride resin, a vinyl chloride resin and another monomer (for example, acetic acid) as an image receiving layer on a support made of paper, a plastic film, or a paper-plastic film composite. And one or more polymer layers of a copolymer resin with vinyl, etc.), polyvinyl butyral, polyvinyl pyrrolidone, polycarbonate and the like.

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

[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 paint- A uniform solution of paint containing a yellow dye (Exemplified Compound No. Y-1), a binder and a solvent shown below was obtained.

Yellow dye (Exemplified Compound No. Y-1) 10 g Nitrocellulose resin 20 g Methyl ethyl ketone 400 ml-Preparation of thermal transfer recording material-The coating amount of the above paint after drying on a 4.5 μm thick polyethylene terephthalate film using a wire bar Was adjusted to 1.0 g / m ² and dried to prepare a heat-sensitive transfer recording material having a heat-sensitive layer formed on a polyethylene terephthalate film.

Note that a nitrocellulose layer containing a silicon-modified urethane resin (SP-2105, manufactured by Dainichi Seika) is provided as a slipping layer on the back surface of the polyethylene terephthalate film.

—Preparation of Image Receiving Material— A polyethylene layer on one side of a paper laminated with polyethylene on both sides (including a white pigment (TiO ₂ ), a bluing agent, and the following metal source (application amount: 5 g / m ² )). Was coated with a vinyl chloride resin containing 0.15 g / m ² of silicon oil as an image receiving layer to a coating weight of 10 g / m ² to obtain an image receiving material.

Metal sole: [Ni (C ₂ H ₅ NHCH ₂ CH ₂ NH ₂ ) ₃ ] ²⁺ [(C ₆ H ₅ ) ₄ B ⁻ ] ₂ The structure of this image receiving material is illustrated in the drawings and is shown in FIG. It is as follows. Polyethylene layers 13a on both sides of paper 12,
13b is laminated, and a polyvinyl chloride layer 14 is laminated on the polyethylene layer 13a on one side.

-Image forming method- The heat-sensitive transfer recording material and the image-receiving material are overlapped so that the heat-sensitive layer surface of the heat-sensitive transfer recording material and the image-receiving layer surface of the image-receiving material face each other. Image recording was performed under the following recording conditions.

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

The maximum density of this image (Dmax), the hue of the dye image (λma
x and Dλ ₅₅₀ ) and image stability (lightfastness). Table 1 shows the results.

Dλ ₅₅₀ represents the absorption concentration (secondary absorption concentration) of the chelate dye at 550 nm.

Recording conditions Main scanning and sub-scanning linear density: 8 dots / mm Recording power: 0.6 W / dot Heating time of thermal head: Heating time was adjusted stepwise between 20 msec and 0.2 msec.

Image stability After the sample was irradiated with light using a xenon fade meter for 96 hours, the residual ratio of the image density was shown.

(Examples 2 to 8) In Example 1, the yellow dye was changed to Exemplified Compound No. Y-
1 to Exemplified Compound Nos. Y-3, Y-8, Y-10, Y-12,
Seven kinds of thermal transfer recording materials were prepared in the same manner as in Example 1 except that Y-15, Y-17 or Y-25 was used, and image recording was performed under the same recording conditions.

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

The maximum density of these images, the hue of the dye image, and the image stability were measured in the same manner as in Example 1. Table 1 shows the results.

(Comparative Examples 1 and 2) Two types of heat-sensitive transfer recording materials were prepared in the same manner as in Example 1 except that the yellow dye was replaced with the following Comparative Dye (A) or (B). Image recording was performed under the same recording conditions.

These images were measured for maximum density, hue, and image stability in the same manner as in Example 1. Table 1 shows the results.

As is clear from Table 1, it was found that the images obtained by the present invention were excellent in maximum density, hue and image stability.

When the thermal transfer recording materials of Comparative Examples 1 and 2 were used, the results were obtained that the comparative dyes (A) and (B) used were insufficiently chelated, resulting in low density and extremely poor light resistance. Was. Further, since the secondary light has a secondary absorption in a green light absorption region, there is a problem in color reproduction.

(Example 9) On the polyethylene terephthalate film used as a support in Example 1, a heat-sensitive layer containing a yellow dye (Exemplary Compound No. Y-1) according to the present invention, a heat-sensitive layer containing a cyan dye having the following structure, A heat-sensitive transfer recording material was prepared by sequentially applying a heat-sensitive layer containing a magenta dye having the following structure.

Note that the same binder as in Example 1 was used for the binder of each heat-sensitive layer.

The amounts of the pigment and the binder were the same as in Example 1.

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

Further, the fixing property and the image stability of this image were both good.

Example 10 5 g of a ball mill dispersion of P-toluamide as an intermediate layer on the thermal transfer recording material of Example 9 and polyvinylpyrrolidone
100 ml of an aqueous solution containing 7 g, gelatin 3 g and the following hardener 0.3 g
Was applied so that the amount of P-toluamide was 0.5 g / m ² .

Further, on the intermediate layer, the same metal source (amount of 1.0 g / m ² ) as used in Example 1 and the following ultraviolet ray inhibitor (amount of the
0.1 g / m ² ), the following antioxidant (0.1 g / m ² ) and an ethylene-vinyl acetate copolymer (vinyl acetate content 20% by weight,
With the amount of 0.2 g / m ²⁾ containing carnauba wax (the biasing 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 thermal transfer material and the image receiving material, full-color image recording was performed by a video printer in the same manner as in Example 9.

 The image receiving material was white plain paper.

The obtained image had good color reproducibility, gradation, and image stability.

[Effects of the Invention] As described in detail above, according to the present invention, a yellow dye image having improved heat diffusion property, chelating property and hue as well as heat resistance, light resistance and fixing property can be obtained from a kind of dye. It is possible to provide a thermal transfer recording material that can be used and an image forming method that can efficiently perform recording using the thermal transfer recording material.

[Brief description of the drawings]

1 and 2 are explanatory views of an image forming method using the thermal transfer recording material of the present invention, and FIG. 3 is a sectional view of the image receiving material. DESCRIPTION OF SYMBOLS 1 ... Support body 2 ... Image receiving layer 3 ... Image receiving material 4 ... Support 5 ... Thermosensitive 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

Claims (2)

(57) [Claims] 1. A heat-sensitive transfer recording material having a layer containing a yellow dye represented by the general formula [I] on a support. [Wherein, R ¹ and R ² each represent a hydrogen atom or a substituent, and Z represents a pyrazole ring, an imidazole ring, a benzopyrazole ring, or a benzo group together with a carbon atom bonded to an azo group and a nitrogen atom bonded to the carbon atom. It represents an atomic group necessary for forming an imidazole ring, a triazole ring or a tetrazole ring. ] 2. An image receiving material is superimposed on a heat-sensitive transfer recording material having a layer containing a yellow dye represented by the general formula [I] on a support, and heat is applied to the heat-sensitive transfer recording material in accordance with image information. Forming an image on an image receiving material using a chelate dye formed by a reaction between the yellow dye and a metal ion. [Wherein, R ¹ and R ² each represent a hydrogen atom or a substituent, and Z represents a pyrazole ring, an imidazole ring, a benzopyrazole ring, or a benzo group together with a carbon atom bonded to an azo group and a nitrogen atom bonded to the carbon atom. It represents an atomic group necessary for forming an imidazole ring, a triazole ring or a tetrazole ring. ]