JPH0462094A - Thermal transfer recording material and thermal transfer recording - Google Patents

Abstract

PURPOSE:To obtain an image with high chromatic density and stability as well as superb color regeneration which are realized by use of a cyan color which becomes chelated during image formation, while being highly resistant against heat and thermally dispersive by providing a layer containing a specific cyan color on a support. CONSTITUTION:In formula (1) of a cyan color, X is an electron-attractive group; Y is an aromatic hetero cyclic containing nitrogen; and R<1> is an aliphatic hydrocarbon group. If a metal ion is allowed to coexist in the image-receiving layer 2 of an image receiving material 3 consisting of a support 1 and an image receiving layer 2, a color in the thermal layer 5 of a thermal transfer recording material 6 consisting of the support 1 and a thermal layer 5 is dispersively migrated to an image receiving material 13 by heat of a thermal resistor 8 in a thermal head 7, for example. Further, the color reacts with a metal ion in the image receiving layer 2 to form a chelate color. A chemical compound which supplies a metal ion is such as inorganic or organic metal salts and metal complexes and preferably organic acid salts and complexes.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a thermal transfer recording material and a thermal transfer recording method, and more specifically, to a thermal transfer recording material and a thermal transfer recording method, and more specifically, to a thermal transfer recording material and a thermal transfer recording method. The present invention relates to a new thermal transfer recording material that allows a cyan dye image to be obtained from a cyan dye with high density, high stability, and is preferable in terms of color reproduction, and a thermal transfer recording method that allows efficient recording using this thermal transfer recording material.

[Prior Art and Problems to be Solved by the Invention] Conventionally, color recording techniques such as inkjet, electrophotography, and thermal transfer have been studied as methods for obtaining color hard copies.

Among these, the thermal transfer method in particular is easy to operate and maintain, and the device can be made smaller and lower in cost.
Furthermore, it has the advantage of low running costs.

In this thermal transfer method, a transfer sheet (thermal transfer recording material), which has a meltable ink layer provided on a support, is heated by a thermal head, and the ink is melted and transferred onto the transfer sheet (image receiving material). A thermal diffusion transfer method (sublimation transfer method) in which a transfer sheet having an ink layer containing a heat-diffusible dye (sublimable dye) on a support is heated by a thermal head to transfer the heat-diffusible dye to the transfer sheet. There are two types of transfer methods (transfer method), but the latter thermal diffusion transfer method changes the amount of dye transferred in response to changes in the thermal energy of the thermal head,
Since it is possible to control the gradation of the image, it is advantageous for full-color recording.

By the way, in thermal transfer recording using the thermal diffusion transfer method,
Dyes used in thermal transfer recording materials are important, and conventional dyes have the disadvantage that the stability of the resulting images, that is, the light fastness and fixing properties are poor.

In order to improve this point, JP-A-59-78893,
No. 59-109:194 and No. 60-2398 disclose an image forming method in which a chelatable heat-diffusible dye is used to form an image on an image-receiving material using the chelated dye. ing.

These image forming methods are excellent methods for improving light fastness and fixing properties, but the cyan dyes disclosed in these publications have low dye solubility in solvents, so it is difficult to obtain sufficient image density. can't get it.

In addition, since the chelation reaction does not proceed sufficiently during image formation, an image is formed using a dye that is not chelated (usually has a shorter wavelength than the chelated dye), and this is not desirable in terms of color reproduction, so improvements should be made. was desired.

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

That is, an object of the present invention is to provide a thermal transfer method that uses a cyan dye that has good heat resistance and thermal diffusivity and is sufficiently chelated during image formation to obtain images with high density, stability, and good brown color reproduction. It is an object of the present invention to provide a recording material and a thermal transfer recording method that allows efficient recording using this thermal transfer recording material.

[Means for solving the above problem] The present invention according to claim 1 for achieving the above object,
This is a heat-sensitive transfer recording material characterized by having a layer containing at least a dye represented by the following general formula [I] on a support.

The present invention according to claim 2 further provides an image-receiving material which is superimposed on the layer of a heat-sensitive transfer material having a layer containing a dye represented by the following general formula [I] on a support, and the image-receiving material is formed into an image of the heat-sensitive transfer material. This is a thermal transfer recording method characterized in that an image is formed on an image-receiving material by heating according to information and using a chelate dye formed by a reaction between the dye and metal ions.

OR' However, in the formula, X is an electron-withdrawing group, Y is a nitrogen-containing heterocycle having aromaticity, and R1 is an aliphatic hydrocarbon group.

To explain the general formula [1] in more detail, preferable examples of X include -No2. -CN, -CF3. -So, R
(wherein R2 is an alkyl group, an aralkyl group, or an aryl group).

Preferred examples of Y include a pyridine ring.

Further, R1 is an aliphatic hydrocarbon group which may have a substituent, and preferably an alkyl group having 1 to 8 carbon atoms. However, when the above-mentioned X is -NO2, it is desirable that this R1 has 2 to 8 carbon atoms, and is more preferably branched.

The dye represented by the general formula [1], that is, the dye according to the present invention is a cyan dye with good heat diffusivity and heat resistance,
Moreover, most of them are highly soluble in solvents.

And, importantly, this cyan dye is capable of reacting with and sufficiently chelating metal ions during image formation.

A typical example of this cyan dye is 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-53-15,533.

The heat-sensitive transfer recording material of the present invention comprises a layer containing a 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 is 90%
．． 1 to 20 g is preferred.

The heat-sensitive layer is prepared by preparing a paint for forming a heat-sensitive layer by dissolving one or more of the pigments together with a binder in a solvent or by dispersing them in the form of fine particles in a solvent, and applying the paint onto a support. It can be formed by coating it on the surface and drying it appropriately.

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

The binders include water-soluble polymers such as cellulose, polyacrylic acid, polyvinyl alcohol, and polyvinylpyrrolidone, acrylic resin, methacrylic resin, polystyrene, polycarbonate, polysulfone, polyether sulfone, polyvinyl butyral, polyvinyl acetal, and nitrocellulose. , ethyl cellulose and the like.

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

The amount of binder used is 0.1 per meter of support.
~50g is preferred.

The solvents include water, alcohols (e.g. ethanol, propatool), alcoholic compounds (e.g. ethyl acetate), aromatics (e.g. toluene, xylene, chlorobenzene), ketones (e.g. acetone, methyl ethyl ketone), ethers (e.g. Examples include tetrahydrofuran, dioxane), chlorinated solvents (eg, chloroform, trichlorethylene), and the like.

The support may be one that has good dimensional stability and can withstand the heat of a thermal head during recording, or a thin paper such as condenser paper or glassine paper, or a heat-resistant material such as polyethylene terephthalate, polyamide, or polycarbonate. A plastic film is preferably used.

The thickness of the support is preferably 2 to 30 Bm, and the support may have a subbing layer for the purpose of improving adhesion with the binder, preventing transfer of the dye to the support, and preventing dyeing. good.

Furthermore, 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 adhering to the support.

The heat-sensitive transfer recording material of the present invention has a heat-sensitive layer on which the heat-sensitive transfer recording material is coated.
It may have a heat-fusible layer containing a heat-fusible compound as described in Japanese Patent No. 106997.

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

Note that these heat-melting layers may contain polymers such as polyvinylpyrrolidone, polyvinyl butyral, and saturated polyester, in order to improve dye retention.

The thermal transfer recording material of the present invention can obtain a cyan dye image from one type of dye, but when applied to full-color image recording, a cyan heat-sensitive layer containing the cyan dye according to the present invention, a cyan dye image containing a magenta dye, etc. It is preferable that a total of three layers, a magenta heat-sensitive layer containing a heat-diffusible yellow dye and a yellow heat-sensitive layer containing a heat-diffusible yellow dye, are sequentially and repeatedly coated on the same surface of the support.

In addition, yellow thermosensitive layer, magenta thermosensitive layer,
In addition to the cyan heat-sensitive layer containing the dye according to the present invention, a total of four heat-sensitive layers containing a black image-forming substance may be repeatedly coated on the same surface of the support.

In the heat-sensitive transfer recording method of the present invention, the heat-sensitive layer of the heat-sensitive transfer recording material and the image-receiving material are superimposed, and then heat corresponding to image information is applied to the heat-sensitive transfer recording material, so that the metal ions and the pigment in the heat-sensitive layer are An image is formed on the image-receiving material by the chelate dye formed by reaction with the image-receiving material.

In this case, in the present invention, by using the cyan dye represented by the general formula [11] as the dye, it is possible to efficiently obtain an image with high density, excellent stability, and favorable brown color reproduction.

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

The above thermal transfer recording material method can be explained using drawings as shown in Figure 2 (
In a), an image receiving material 3 consisting of a support l and an image receiving layer 2
When the metal ions are present in the image-receiving layer 2 of
The dye therein is diffused into the image receiving material 3 by heat from the heating resistor 8 of the thermal head 7, reacts with the metal ion in the image receiving layer 2, and forms a chelate dye.

In addition, in FIG. 2(b), when the metal ions are present in the heat-fusible layer 9 provided on the surface of the heat-sensitive layer 5, the support 4, the heat-sensitive layer 5, and the heat-fusible layer 9 are formed. The dye in the heat-sensitive layer 5 of the heat-sensitive transfer recording material 10 is diffused and transferred to the heat-fusible layer 9 by heat from the heating resistor 8 of the thermal head 7, where it reacts with the metal ion to form a chelate dye. Then, the heat-melting substance 9a containing the chelate dye forms the image-receiving material 3 due to cohesive failure or interfacial peeling.
to move to.

Examples of the metal ions include divalent and polyvalent metals belonging to the first to subgroups of the periodic table, among which AM
, Go, Cr, Cu, Fe, Mg, Mn, M
o, Ni, Sn, Ti and Zn are preferred, and Ni, Cu, Cr, Go and Zn are particularly preferred.

Compounds that supply these metal ions (see below).

It is sometimes called metal sauce. ) include inorganic or organic salts of the metal and complexes of the metal,
Among these, salts and complexes of organic acids are preferred.

To give a specific example, %i2+, Cu2O, (:, 2+,
Examples include salts of lower fatty acids such as Go ``+'' and Zn'' with acetic acid, salts of higher fatty acids such as stearic acid, and salts of aromatic carboxylic acids such as benzoic acid and salicylic acid.

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

[M(Ql)1 (Q2) −((h)n] ”(Y
-) In the above formula, M is a metal ion, preferably %i2*, Cu2+, Cr, C02+, zn
Represents 2+.

Q□, Q, , Q each represent a coordination compound capable of forming a coordination bond with the metal ion represented by M, and may be the same or different.

These coordination compounds include, for example, chelate chemistry (
5) (Nankodo).

Y represents an organic anion, and specific examples thereof include tetraphenylboron anion and alkylbenzenesulfonate anion.

The sentence represents an integer of 1, 2, or 100, m represents l, 2, or O, and n represents 1 or O. or by the number of ligands of Q, , Q, , Q3.

p represents 1 or 2, preferably 2;

When P is 2, the coordination group of the coordination compound represented by Q, , Q, , Q3 is not anionized.

The amount of the metal source added is usually 1 to 20 g/m, preferably 0.5 to 20 g/m, based on the image receiving material or thermally fused layer.
g/m” or more preferably.

The image-receiving material used in the present invention generally uses paper, a plastic film, or a paper-plastic film composite as a support, and forms an image-receiving layer thereon with polyester resin, polyvinyl chloride resin, vinyl chloride, and other monomers ( For example, a layer of one or more polymers such as a copolymer resin with vinyl acetate, polyvinyl butyral, polyvinylpyrrolidone, polycarbonate, etc. is formed.

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

[Example] Next, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited thereto.

(Example 1) One coating material was mixed with the following raw materials to obtain a uniform solution coating material containing the heat-diffusible pigment according to the present invention.

Heat-diffusible dye C-1 (see Figure 1) 10g Nitrocellulose resin 20g Methyl ethyl ketone
...... 400 ml - Preparation of heat-sensitive transfer recording material - The above paint was applied onto a polyethylene terephthalate film with a thickness of 4.5 pm using a wire bar so that the coating amount after drying was 1.0 g/m''. A heat-sensitive transfer recording material was prepared by coating and drying the polyethylene terephthalate film to form a heat-sensitive layer thereon.

Note that a nitrocellulose layer containing a silicone-modified urethane resin (SP-2105, manufactured by Dainichiseika Chemical Co., Ltd.) is provided on the back surface of the polyethylene terephthalate film as a sticking prevention layer.

Image-receiving material - Polyethylene is laminated on both sides of paper, and on one side of the polyethylene layer [containing a white pigment (TiOz), a bluing agent, and the following metal source (applied amount: 5 g/m2)], 0.05 g/m2 is applied as an image-receiving layer. A vinyl chloride resin containing 15 g/m 2 of silicone oil was coated in an amount of 10 g/m 2 to obtain an image-receiving material.

Metal source: [N1(c2o511)1ct+2c1(211)12
Moonha[(C68%)4B1 t--Thermal transfer recording method-- The thermal transfer recording material and the image receiving material are stacked so that the surface of the thermal layer of the thermal transfer recording material and the image receiving surface of the image receiving material face each other, and the thermal head is Apply it from the back side of the thermal transfer recording material,
Image recording was performed under the following recording conditions.

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

Maximum density of this image (D11□), chelation reactivity,
Table 1 shows the results of evaluating the hue and fixability of the dye images in the following manner.

Linear density of main scanning and sub-scanning = 8 dots/■ Recording crab 0.6 W/dot Heating time of thermal head: Heating time was adjusted stepwise from 20 sec to 0.2 m5 ec.

Evaluation of chelation reactivity: Q: The chelate dye image is sufficiently formed.

△: Insufficient formation of chelate dye.

Only some pigments form chelate pigments.

Hue rating: 0...Preferable as a cyan image.

△...Has secondary absorption at 500-600□ (absorption of non-chelate dye).

X: Absorption of non-chelated dye is greater than that of chelated 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 gm thick nitrocellulose layer on a 1807 tm thick polyethylene terephthalate film, and then heated at 140°C for 1 minute. The degree of transfer of the dye from the image-receiving layer to the surface of the nitrocellulose layer was visually evaluated by heating, and it was determined that the less retransfer, the better the fixing property.

○... Re-transfer is hardly recognized.

△: Re-transfer is not observed.

X: Significant retransfer.

(Examples 2 to 8) In Example 1, the dyes were C-2, C-4, C-S, C
The above thermal transfer recording material was prepared in substantially the same manner as in Example 1 except that -6, C-8, C-10, and C-13 were used, and images were recorded under the same recording conditions.

However, in Example 8, if the amount of solvent remained as in Example 1, the pigment would not be completely dissolved, so the amount of methyl ethyl ketone used was doubled when preparing the paint.

As a result of image recording, cyan dye images with excellent gradation were obtained in all cases.

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

The results are shown in Table 1.

(Comparative Examples 1 to 3) Three types of thermal transfer recording materials were prepared in almost the same manner as in Example 1, except that the dyes in Example 1 were replaced with the following comparative dyes A, B, and C. Image recording was performed under the recording conditions.

Comparative dye A: Comparative dye B: CR3 Comparative dye C: H Table 1 The maximum density of the obtained image, the chelation reactivity of the dye, the hue and fixability of the dye image were evaluated.

The results are shown in Table 1.

(Hereinafter, blank space) As can be seen from Table 1, in the examples of the present invention, the dye transferability, hue, and chelation reactivity were good, and it was possible to obtain images with high density and favorable color reproduction.

[Effects of the Invention] According to the present invention, a heat-sensitive transfer recording material is provided, which is made from a cyan dye with excellent heat resistance, thermal diffusivity, and chelate reactivity, and which provides a dye image with high density, high stability, and excellent brown color reproduction. , it is possible to provide a thermal transfer recording method that allows efficient recording using the same.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the structural formula of a typical cyan dye according to the present invention. FIGS. 2A and 2B are explanatory diagrams of the thermal transfer recording method of the present invention. ■...Support, 2...Image receiving layer, 3...Image receiving material,
4...Support, 5...Thermosensitive layer, 6...Thermosensitive transfer recording material, 7...Thermal head, 8...Heating resistor, 9...Thermofusible layer, 10... Heat-sensitive transfer recording material.

Claims (2)

[Claims] (1) A thermal transfer recording material characterized by having on a support a layer containing at least a dye represented by the following general formula [I]. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [I] [However, in the formula, X is an electron-withdrawing group, Y is a nitrogen-containing heterocycle with aromaticity, and R^1 is an aliphatic hydrocarbon. It is the basis. ] (2) An image-receiving material is superimposed on the layer of a heat-sensitive transfer recording material having a layer containing a dye represented by the general formula [I] according to claim 1 on a support, and the heat-sensitive transfer recording material is converted into image information. 1. A thermal transfer recording method, characterized in that an image is formed on an image-receiving material using a chelate dye formed by a reaction between the dye and a metal ion.