JP2964464B2 - Thermal transfer recording material and thermal transfer recording method - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a thermal transfer recording material and a thermal transfer recording method, and more particularly, to a thermal transfer recording material and a thermal transfer recording method, which has heat diffusibility and heat resistance and has excellent chelation reactivity. The present invention relates to a novel thermal transfer recording material capable of obtaining a cyan dye image with high density and high stability from a cyan dye and having high stability, and a thermal transfer recording method capable of efficiently recording using the thermal transfer recording material.

[Prior Art and Problems to be Solved by the Invention] Conventionally, as a method for obtaining a color hard copy, a color recording technique using 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 this 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 to transfer ink to a transfer sheet (image receiving material).
And a transfer sheet having an ink layer containing a heat-diffusible dye (sublimable dye) on a support is heated by a heat-sensitive head to transfer the heat-diffusible dye to a transfer-receiving sheet. There are two types of thermal diffusion transfer method (sublimation transfer method), but the latter thermal diffusion transfer method controls the gradation of the image by changing the amount of dye transfer according to the change in thermal energy of the thermal head. So you can
This is advantageous for full-color recording.

By the way, in the thermal transfer recording of the thermal diffusion transfer system, the dye used in the thermal transfer recording material is important,
The conventional one has a drawback that the stability of the obtained image, that is, the light resistance and the fixing property are not good.

To improve the point, JP-A-59-78893, 59-1
JP-A-09394 and JP-A-60-2398 disclose an image forming method for forming an image on an image receiving material by using a chelatable dye by using a chelatable thermodiffusable dye.

These image forming methods are excellent methods for improving light fastness and fixability, but the cyan dyes disclosed in these publications have a low solvent solubility of the dye, so that sufficient image density can be obtained. I can't get it.

Further, since the chelation reaction does not proceed sufficiently during image formation, an image is formed on the image by a dye that is not chelated (usually, a shorter wavelength than the chelated dye),
Since this point is not preferable in color reproduction, improvement has been desired.

The present invention has been made to improve the above situation.

That is, an object of the present invention is to provide a heat-sensitive transfer which has good heat resistance and heat diffusibility, and uses a cyan dye which is sufficiently chelated at the time of image formation to obtain a high-density, high-stability and color-reproducible image. An object of the present invention is to provide a recording material and a thermal transfer recording method capable of efficiently recording using the thermal transfer recording material.

[Means for Solving the Problems] The present invention according to claim 1 for attaining the above object has at least a layer containing a dye represented by the following general formula [I] on a support. This is a heat-sensitive transfer recording material.

Further, the present invention according to claim 2 has the following general formula [I]:
An image-receiving material is superimposed on the layer of a thermal transfer material having a layer containing a dye represented on a support, and the thermal transfer material is heated according to image information, and formed by a reaction between the dye and metal ions. This is a thermal transfer recording method characterized in that an image is formed on an image receiving material with a chelating dye.

Wherein X is an electron-withdrawing group; Is a nitrogen-containing heterocyclic ring having aromaticity, R ¹ is an aliphatic hydrocarbon group which may have a substituent, and when X is NO ₂ , the substituent is a carbamoyl group. except.

To explain in more detail the general formula [1], the preferable examples of _{X, -NO 2, -CN, -CF} 3, -SO 2 R 2 ( wherein R
² is an alkyl group, an aralkyl group or an aryl group. ).

And a pyridine ring.

R ¹ is an aliphatic hydrocarbon group which may have a substituent, preferably an alkyl group having 1 to 8 carbon atoms. However, when X is —NO ₂ , R ¹ preferably has 2 to 8 carbon atoms, and more preferably is branched.

The dye represented by the general formula [1], that is, the dye according to the present invention is a cyan dye having good heat diffusibility and heat resistance, and most of them are rich in solvent solubility.

Importantly, the cyan dye reacts with metal ions during image formation and can be sufficiently chelated.

A typical example of this cyan dye is as shown in FIG.

The dye represented by the general formula [I] can be produced, for example, according to the synthesis method disclosed in JP-A-53-35,533.

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

The content of the dye in the heat-sensitive layer was determined per 1 m ² of the support.
0.1-20 g is preferred.

The heat-sensitive layer is prepared by dissolving one or more of the dyes in a solvent together with a binder, or by dispersing the dye in the form of fine particles in a solvent to prepare a heat-sensitive layer-forming coating, and coating the coating on a support. And dried as appropriate.

 The thickness of the heat-sensitive layer is preferably from 0.1 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 0.1-5
0 g is preferred.

Examples of the solvent include water, alcohols (eg, ethanol, 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.

The support may be any one that has good dimensional stability and can withstand the heat of the thermal head at the time of recording, but it can be heat-resistant such as condenser paper, thin paper such as glassine paper, polyethylene terephthalate, polyamide, and polycarbonate. Is preferably used.

The thickness of the support is preferably from 2 to 30 μm, and the support may have an undercoat layer for the purpose of improving adhesion with a binder or transferring a dye to the support, or preventing dyeing. Good.

Further, a slipping layer may be provided on the back surface of the support (the side opposite to 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-59-1980.
It may have a heat-fusible layer containing a heat-fusible compound as described in JP-A-06997.

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 thereof include alcohols such as xylitol, amides such as acetamide and benzoamide, 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 thermal transfer recording material of the present invention can obtain a cyan dye image from a kind of dye, but when applied to full-color image recording, it contains a cyan thermosensitive layer containing a cyan dye according to the present invention and contains a magenta dye. Magenta thermal layer,
It is preferable that a total of three yellow heat-sensitive layers containing a heat-diffusable yellow dye are sequentially and repeatedly applied on the same surface of the support.

Further, if necessary, a total of four layers of a yellow thermosensitive layer, a magenta thermosensitive layer, a cyan thermosensitive layer containing the dye according to the present invention, and a thermosensitive layer containing a black image forming substance are sequentially formed on the same surface of the support. It may be repeatedly applied.

In the heat-sensitive transfer recording method of the present invention, the heat-sensitive transfer recording material is superposed on the heat-sensitive layer and the image-receiving material, and then heat is applied to the heat-sensitive transfer recording material in accordance with image information. An image is formed on the image receiving material by the chelate dye formed by the reaction with the dye.

In this case, in the present invention, since the cyan dye represented by the general formula [1] is used as the dye, an image having high density, high stability and favorable in color reproduction can be efficiently obtained.

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 above thermal transfer recording method will be described with reference to the drawings. In FIG. 2A, when the metal ions are present in the image receiving layer 2 of the image receiving material 3 comprising the support 1 and the image receiving layer 2, the support 4 The dye in the heat-sensitive layer 5 of the heat-sensitive transfer recording material 6 including the heat-sensitive layer 5 is diffused and transferred to the image-receiving material 3 by, for example, heat from the heat-generating resistor 8 of the thermal head 7. Reacts with to form a chelating dye.

In addition, in FIG. 2B, when the metal ions are present in the heat-meltable layer 9 provided on the surface of the heat-sensitive layer 5,
The dye in the heat-sensitive layer 5 of the heat-sensitive transfer recording material 10 including the support 4, the heat-sensitive layer 5, and the heat-meltable layer 9 is transferred to the heat-meltable layer 9 by, for example, heat from the heat-generating resistor 8 of the thermal head 7. Diffusion transfer occurs, where it reacts with the metal ions to form a chelate dye, and the heat-meltable substance 9a containing this chelate dye transfers to the image receiving material 3 by cohesive failure or interface peeling.

Examples of the metal ion include divalent and polyvalent metals belonging to Groups I to XIII of the periodic table.
Al, Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Sn, Ti and Zn
Are preferred, and particularly preferred are Ni, Cu, Cr, Co and Zn.

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
Salts of lower fatty acids such as ²⁺ 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 where} M is a metal ion, preferably Ni ²⁺ ,
Represents 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.

These coordination compounds can be selected, for example, from 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, which means that the complex represented by the above general formula is tetradentate or hexadentate. Or the number of ligands in 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.

Usually, the addition amount of the metal source is preferably 0.5 to ²⁰ g / m ^2, more preferably 1 to 20 g / m ² , based on the image-receiving material or the hot-melt layer.

The image-receiving material used in the present invention is generally a paper, a plastic film, or a paper-plastic film composite as a support, on which a polyester resin, a polyvinyl chloride resin, a vinyl chloride and other monomers ( One or two or more polymer layers of a copolymer resin with, for example, vinyl acetate), polyvinyl butyral, polyvinyl pyrrolidone, polycarbonate and the like are formed.

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) -Paint- The following raw materials were mixed to obtain a paint of a uniform solution containing the heat diffusible dye according to the present invention.

Thermal diffusible dye C-1 (see Fig. 1) 10 g nitrocellulose resin 20 g methyl ethyl ketone 400 ml-Preparation of thermal transfer recording material- Was applied and dried so that the coating amount after drying was 1.0 g / m ² , to produce 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 on the back surface of the polyethylene terephthalate film as an anti-sticking layer.

- receiving material - on the polyethylene layer of one side laminated with polyethylene on both sides of the paper [white and a pigment (TiO ₂₎ and a bluing agent and the following metal source (per weight 5g / m ^2)], the image-receiving layer Then, a vinyl chloride resin containing 0.15 g / m ² of silicone oil was applied so as to have a coating amount of 10 g / m ² to obtain an image receiving material.

Metal sole: [Ni (C ₂ H ₅ NHCH ₂ CH ₂ NH ₂ )] ²⁺ [(C ₆ H ₅ ) ₄ B] ₂ ^-- Thermal transfer recording method-Thermal transfer between the thermal transfer recording material and the image receiving 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 cyan image having excellent gradation was obtained.

Table 1 shows the results of evaluation of the maximum density ( _Dmax ), chelation reactivity, hue and fixability of the dye image of the image in the following manner.

Linear density of main scanning and sub-scanning: 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.

Evaluation of chelation reactivity: ：: A chelate dye image was formed almost completely.

Δ: Insufficient formation of chelate dye.

X: Chelate dye is formed only in part of the dye.

Evaluation of hue:…: Preferred as a cyan image.

Δ: Secondary absorption at 500 to 600 _nm (absorption of non-chelating dye).

×: Absorption of non-chelating dye is larger than that of chelating dye.

Evaluation of fixability: The surface of the image receiving layer of the obtained image was overlapped with the coated surface of a transfer sheet formed by coating a 5 μm-thick nitrocellulose layer on a 180 μm-thick polyethylene terephthalate film, and heated at 140 ° C. for 1 minute. Then, the degree of transfer of the dye from the image receiving layer to the surface of the nitrocellulose layer is visually evaluated,
The smaller the retransfer, the better the fixability.

…: Retransfer is hardly recognized.

Δ: No retransfer was observed.

×: retransfer is remarkable.

(Examples 2 to 8) In Example 1, the dyes were C-2, C-4, C-5,
Seven kinds of thermal transfer recording materials were prepared in substantially the same manner as in Example 1 except that C-6, C-8, C-10, and C-13 were used, and image recording was performed under the same recording conditions. .

However, in Example 8, the amount of methyl ethyl ketone used was doubled at the time of preparation of the coating, because the dye was not completely dissolved when the amount of the solvent was the same as in Example 1.

As a result of the image recording, a cyan dye image having excellent gradation was obtained.

The maximum density of these images, the chelation reactivity of the dye,
The hue and fixability of the dye image were similarly evaluated.

 Table 1 shows the results.

(Comparative Examples 1 to 4) In Example 1, the following comparative dyes A and B were used as dyes.
Four types of heat-sensitive transfer recording materials were prepared in substantially the same manner as in Example 1 except that C and D were used, and image recording was performed under the same recording conditions.

Maximum density of the obtained image, chelation reactivity of the dye,
The hue and fixability of the dye image were evaluated.

 Table 1 shows the results.

As can be seen from Table 1, in the examples of the present invention, the transferability of the dye, the hue, and the chelation reactivity are good, and a high-density image that is favorable for color reproduction can be obtained.

[Effects of the Invention] According to the present invention, there is provided a heat-sensitive transfer recording material capable of obtaining a dye image having high stability at a high density and excellent color reproduction from a cyan dye excellent in heat resistance, heat diffusion property and chelate reactivity. ,
It is possible to provide a thermal transfer recording method capable of efficiently recording by using the method.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing the structural formula of a typical cyan dye according to the present invention. FIGS. 2A and 2B are explanatory views of the thermal transfer recording method of the present invention. DESCRIPTION OF SYMBOLS 1 ... Support, 2 ... Image receiving layer, 3 ... Image receiving material, 4 ...
Support, 5 ... heat-sensitive layer, 6 ... heat-sensitive transfer recording material, 7 ...
... thermal head, 8 ... heating resistor, 9 ... heat-fusible layer, 10 ... thermal transfer recording material.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-59-78893 (JP, A) JP-A-59-171688 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B41M 5/38-5/40 CA (STN) REGISTRY (STN)

Claims (2)

(57) [Claims] 1. A heat-sensitive transfer recording material comprising a support having at least a layer containing a dye represented by the following general formula [I] on a support. [Where X is an electron-withdrawing group; Is a nitrogen-containing heterocyclic ring having aromaticity, R ¹ is an aliphatic hydrocarbon group which may have a substituent, and when X is NO ₂ , as the substituent, a carbamoyl group is excluded. . ] 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 general formula [I] according to claim 1 on a support, and said thermal transfer recording material is imaged. A heat-sensitive transfer recording method comprising heating according to information and forming an image on an image receiving material by a chelate dye formed by a reaction between the dye and a metal ion.