JPH0489289A - Thermally transferable recording material and thermally transferable recording method - Google Patents

Abstract

PURPOSE:To obtain an image with superb gradation density, excellent light-fastness and fixing properties as well as satisfactory high density and enable efficient data recording using a recording material described below by forming a layer containing a color expressed by a specific formula. CONSTITUTION:A recording material consists of a thermal layer containing a color shown by formula I provided on a support, and the color is a cyan color having excellent heat dissipation and heat resistance. The paint for formation of the thermal layer is prepared by dissolving one or more than two types of color in a solvent with a binder or dispersing the color in the form of fine particles. Then this paint is applied to the support and is dried to form the thermal layer. The support is such as can withstand heat generated by a thermal head and is represented by a thin leaf sheet like a capacitor paper or a heat-resistant plastic film like polyethylene terephthalate. The color contained in the thermal layer 5 of a thermally transferable recording material consisting of the support 4 and the thermal layer 5 becomes dispersed and migrated to an image-receiving material 3 due to heat generated by the thermal resistor of a thermal head and becomes a chelate color through chemical reaction with a metal ion in the image-receiving layer 2.

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 particularly, to a thermal transfer recording material and a thermal transfer recording method. The present invention relates to a heat-sensitive transfer recording material that provides images with excellent color reproduction and high density, and a heat-sensitive transfer recording method that enables efficient recording using this heat-sensitive 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 considered as methods for obtaining color hard copies.

Among these, the thermal transfer method in particular is easy to operate and maintain, and the equipment can be made smaller and lower in cost.
Furthermore, it has advantages such as low running cost.

This thermal transfer method involves heating a transfer sheet (thermal transfer recording material), which has a meltable ink layer on a support, with a thermal head to melt and transfer the ink onto a 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 heat-sensitive head to transfer the heat-diffusible dye to a transfer sheet. There are two types of transfer methods (transfer methods), and the latter is the thermal diffusion transfer method, which changes the amount of dye transferred according to changes in the thermal energy of the thermal head.
It is advantageous for full-color recording because the gradation of the image can be controlled.

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,
Publications No. 59-109394 and No. 60-2398 disclose an image forming method in which a chelatable heat-diffusible dye is used to form an image with the chelated dye on an image-receiving material. .

These image forming methods are excellent methods for improving light fastness and fixing properties.The cyan dyes disclosed in these publications have low solubility in solvents and do not provide sufficient image density. I can't seem to get it.

In addition, since the chelation reaction does not proceed sufficiently during image formation, an image with unchelated dye (usually shorter wavelength than the chelated dye) is also formed on the image, which is unfavorable for color reproduction. It was wanted.

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

In other words, one object of the present invention is to provide a heat-sensitive transfer method that uses a heat-diffusible cyan dye that is sufficiently chelated during image formation to obtain images that are excellent in gradation, light fastness, and fixing properties, and have high density and are favorable for color reproduction. An object of the present invention is to provide a recording material and a thermal transfer recording method that enables 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 a dye represented by the following general formula [I] on a support.

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

However, in the formula, G represents a chelatable group; Z represents an atomic group that forms a 5- or 6-membered heterocycle with atoms, and Z represents an atomic group that forms an aromatic carbocycle or heterocycle with two carbon atoms.

Hereinafter, general formula [I] will be further explained in detail.

The above G represents a chelatable group, for example -〇H
Examples include 1-OR1-SR (wherein R is an alkyl group having 1 to 5 carbon atoms).

Among these, -OH is particularly preferred.

The above X represents an atomic group forming an aromatic carbocycle or a heterocycle together with four carbon atoms.

Among these rings, 5- or 6-membered aromatic carbon rings are preferred, and benzene rings are particularly preferred.

The aromatic carbocycle or heterocycle is not limited to a single ring, and may be fused with another ring.

For example, when the aromatic carbocycle is benzene, the benzene ring may be fused with another ring to form a fused ring such as a naphthalene ring.

The above Y represents an atomic group forming a 5- or 6-membered heterocycle, and aromatic 5- or 6-membered heterocycles are preferred, with pyridine rings, pyrazole rings, triazole rings, etc. being particularly preferred. .

The above Z represents an atomic group forming an aromatic carbocycle or a heterocycle together with two carbon atoms.

Among these rings, 5- or 6-membered aromatic carbon rings are preferred, and benzene rings are particularly preferred.

The aromatic carbocycle or heterocycle is not limited to a single ring, and may be fused with another ring.

For example, when the aromatic carbocycle is benzene, the benzene ring may form a fused ring with another ring, such as a naphthalene ring.

Note that x, Y, and Z may have a substituent.

Examples of this substituent include alkyl groups (e.g., methyl group, ethyl group, etc.), aryl groups (e.g., phenyl group, etc.), alkoxy groups (e.g., methoxy group, ethoxy group, i-propoxy group, ethylpentoxy group, etc.), Amino group (e.g. methylamino group, dimethylamino group, ethylamino group, diethylamino group, etc.), acylamino group (e.g. acetylamino group, etc.), sulfonyl group (e.g. methanesulfonyl group, etc.), alkoxycarbonyl group (e.g. methoxycarbonyl group) , hydroxyl group, cyano group,
Examples include a nitro group, a halogen atom (for example, a chlorine atom, a fluorine atom, etc.).

The dye represented by the general formula [11], 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.

Importantly, this cyan dye can react with metal ions to form a chelate 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-59-208551.

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%
．． 05 to 10 g is preferred.

The heat-sensitive layer is prepared by preparing a paint for forming a heat-sensitive layer by dissolving or dispersing one or more of the pigments in a solvent together with a binder in the form of fine particles, and coating this paint on a support and drying it appropriately. By doing this, you can form it.

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. , ethylcellulose, etc.

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

The amount of binder used is 0.000.
05-30g is preferred.

The solvents include water, alcohols (e.g. ethanol, propatool), cellosolves (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 heat-sensitive 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 gm, 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, an anti-sticking layer may be provided on the back side 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, a colorless or white compound having a melting point of 65 to 130°C is preferably used,
For example, waxes such as carnauba wax, beeswax, 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.

These heat-melting layers may contain a polymer such as polyvinylpyrrolidone, polyvinyl butyral, or saturated polyester in order to enhance the retention of one dye.

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

In addition, if necessary, a total of four layers, including a yellow heat-sensitive layer, a magenta heat-sensitive layer, a cyan heat-sensitive layer containing the dye according to the present invention, and a heat-sensitive layer containing a black image forming substance, may be sequentially repeated on the same surface of the support. It may be painted.

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 is applied to the heat-sensitive transfer recording material according to image information, so that the metal ions and the pigment in the heat-sensitive layer are heated. An image is formed on the image-receiving material by the chelate dye formed by reaction with the image-receiving material.

In this case, the present invention uses a cyan dye represented by the general formula [1] as the dye to efficiently obtain a cyan image that is rich in light fastness and fixability, has high density, and is preferable in terms of color reproduction. I can do it.

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 a drawing as shown in Fig. 2 (
In b), when the metal ions are present in the image receiving layer 2 of the image receiving material 3 consisting of the support 1 and the image receiving layer 2, the heat sensitive layer of the thermal transfer recording material 6 consisting of the support 4 and the heat sensitive layer 5 The dye in 5 is diffused and transferred to the image receiving material 3 by heat from the heating resistor of the thermal head 7, and reacts with the metal ion in the image receiving layer 2 to form 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 transferred to the heat-fusible layer 9 by heat from the heating resistor of the thermal head 7, for example.
There, it reacts with the metal ions to form a chelate dye, and a part or all of the heat-fusible layer 9a containing the chelate dye undergoes cohesive failure or interfacial peeling and transfers to the image-receiving material 3.

Examples of the metal ions include divalent and polyvalent metals belonging to Groups 1 to 2 of the periodic table, including A, Go, Cr, Cu, Fe1Mg, iln,
Mo.

Ni, Sn, Ti and Zn are preferred, especially Ni
, Cu, Cr, co and Zn are preferred.

Compounds that supply these metal ions (hereinafter sometimes referred to as metal sources) include inorganic or organic salts of the metals and complexes of the metals, especially salts and complexes of organic acids. preferable.

To give a specific example, Ni 2 (″Qut+, Cr2
♦, salts of lower fatty acids such as CO24 and zn 2 +'' 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.

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

[M(Q') + (Q2) - (Q')n]"
(z −).

However, in the above formula, M is a metal ion, preferably Ni'',
Cu", Cr2"", (o 2 +, Zn").

Q', Q', and Q3 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).

2 represents an organic anion, and specific examples include a tetraphenylboron anion and an alkylbenzenesulfonate anion.

The sentence represents l, 2 or 3, m represents 1.2 or O, n represents 1 or 0, or are these a complex represented by the above general formula, a tetradentate coordination, or a hexadentate coordination? or Q', Q2. It is determined by the number of ligands of Q'.

p represents 1 or 2, preferably 2;

When P is 2, the coordination groups of the coordination compound represented by Q', Q2, and Q3 are not anionized.

The amount of the metal source added is usually 0.5 to 20 g/m2, preferably 1 to 2 g/m2, relative to the image receiving material or thermally fused layer.
0 g/m2 is more preferred.

The image-receiving material used in the present invention generally uses paper, plastic film, or a paper-plastic film composite as a support, and the image-receiving layer is formed on the support by polyester resin, polyvinyl chloride resin, vinyl chloride, or other materials. - (for example, vinyl acetate, etc.), polyvinyl butyral, polyvinyl and lolidone, polycarbonate, etc., or a layer of one or more polymers is formed.

Further, the support itself can 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): 10 g Nitrocellulose resin: 20 g Methyl ethyl ketone: 400 ml - Preparation of heat-sensitive transfer recording material - The above paint was The coating amount after drying was measured using a wire bar on a polyethylene terephthalate film with a thickness of 4.5 ALm. A heat-sensitive transfer recording material was prepared by coating and drying so as to give Og/rn' and forming a heat-sensitive layer on a polyethylene terephthalate film.

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 an anti-sticking layer.

One image-receiving material has polyethylene layers laminated on both sides of a sheet of paper, and one side of the polyethylene layer [contains appropriate amounts of a white pigment (Ti0a), a bluing agent, and the following metal source (applied amount: 5 g/m').

A vinyl chloride resin containing 0.]5 g/m'' of silicone oil was applied thereon as an image-receiving layer in an amount of 10 g/m<2 >to obtain an image-receiving material.

Metal source: [+1i (C2H5NHCH2CH2NH2)] 2″
``[(C,Hs)4B] 2--Thermal transfer recording method-- The thermal transfer recording material and the image-receiving material are stacked so that the heat-sensitive layer surface of the thermal transfer recording material and the image-receiving surface of the image-receiving material face each other, and a 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 one-tone gradation and light fastness was obtained.

The maximum reflection density (D-, .), chelation reactivity, hue, and fixability of this image were evaluated in the following manner, and the results are shown in Table 1.

Linear density of main scanning and sub-scanning / 8 dots/■■ Recording voltage
Heating time of crab 0.6W/dot heat-sensitive head: Heating time was adjusted stepwise from 20ssec to 0.2sec.

Maximum reflection density: Measured using an optical densitometer [Model PCA-65 manufactured by Konica Corporation.

Chelation reactivity: ○: The chelate dye was sufficiently formed.

Δ: Chelate dye formation was insufficient.

X: Only some of the dyes formed chelates.

Hue rating: ○Preferable as a Nijian image.

Δ: Has secondary absorption at 500 to 600 nm (absorption of non-chelate dye).

×, absorption of non-chelated dye is greater than that of chelated dye.

Fixability.

The image-receiving layer surface on which the image was formed and the nitrocellulose layer surface of a sheet in which a 5 pm thick nitrocellulose layer was provided on a 18,071 m thick polyethylene terephthalate film were placed on top of each other and heated at 140° C. for 1 minute to form the nitrocellulose layer surface. The degree of retransfer of the dye was visually evaluated.

According to this evaluation method, it is shown that the smaller the degree of retransfer, the better the fixing performance.

○, Re-transfer is hardly recognized.

△, retransfer is recognized.

X: Significant retransfer.

(Example 2-8) Dye C-1 in Example 1 was replaced with C-2, C-3, C-4
, C-5, C-7, C-8, and C-10 (all shown in FIG. 1), but in the same manner as in Example 1, seven types of thermal transfer recording materials were prepared.

In Example 8, the amount of methyl ethyl ketone used was doubled when preparing the paint.

Images were recorded on the above seven types of thermal transfer recording materials under the same recording conditions as in Example 1, and cyan images with excellent gradation and light resistance were obtained in all cases.

These images were similarly evaluated for maximum reflection density, chelation reactivity, image hue, and fixability.

The results are shown in Table 1.

(Comparative Examples 1 to 3) The dye used in Example 1 was referred to as Comparative Dye A below.

Three types of thermal transfer recording materials were prepared in substantially the same manner as in Example 1, except that B and C were replaced, and images were recorded under the same recording conditions.

However, in each comparative example, the amount of methyl ethyl ketone used was doubled because the dye was not completely dissolved when the amount of solvent was the same as in Example 1.

Comparative dye A: The maximum reflection density, chelation reactivity, hue of the image, and fixability of the obtained image were evaluated in the same manner.

The results are shown in Table 1.

H H2 (Hereafter, margin) Comparative dye B OCR.

Comparative dye C: OCH.

As is clear from Table 1, according to each of the examples, a high density cyan image with excellent hue and fixability can be obtained due to sufficient chelation.

On the other hand, in each of the comparative examples, not only were images with low density and fixability obtained due to insufficient chelation of the dyes, but also secondary absorption in the blue light absorption range caused color problems. There remains a problem with reproduction.

(Example 9) As shown in FIG. 3, on the polyethylene terephthalate film 11 (having the anti-staking layer 15 on the back side) used as the support in Example 1, a yellow thermosensitive film containing a yellow dye having the following structure was applied. Layer 12, a magenta heat-sensitive layer 13 containing a magenta dye having the following structure, and a cyan heat-sensitive layer 14 containing a cyan dye (C-1) according to the present invention were sequentially coated to prepare a heat-sensitive transfer recording material.

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

Furthermore, the amounts of dye and binder applied were the same as in Example 1.

yellow pigment.

(Example 10) As an intermediate layer on the heat-sensitive transfer recording material of Example 9, 100 ml of an aqueous solution containing 5 g of a ball mill dispersion of P-toluamide, 7 g of polyvinylpyrrolidone, 3 g of gelatin, and 0.3 g of the following hardening agent was added to the thermal transfer recording material of Example 9. Amount applied: 0.5g/r
It was painted so that it became n'.

Magenta dye hardener; Next, using the above heat-sensitive transfer recording material and the same image-receiving material as in Example 1, a video printer (manufactured by Hitachi, VY-1) was used.
When a full-color image was created using 00), a full-color image with excellent fixability, gradation, light fastness, and color reproducibility was obtained.

Further, on the intermediate layer, as a heat-fusible layer, the metal source (applied amount: 0.117 m2), the ultraviolet ray inhibitor (
0.1g/m'), the following antioxidant (0.1g/m')
．． 1 g/rn') and ethylene-vinyl acetate copolymer (
Vinyl acetate content 20% by weight, amount 0.2g/rn'
) was applied by hot-melt coating to obtain a heat-sensitive transfer recording material.

Using this heat-sensitive transfer recording material and image-receiving material, a full-color image was recorded using a video printer in the same manner as in Example 9.

Note that plain white paper was used as the image-receiving material.

The resulting full-color image had a favorable hue in terms of color reproducibility, and had good fixability, light fastness, and gradation.

Ultraviolet inhibitor: [Effects of the invention] According to the present invention, from a heat-diffusible cyan dye with good chelation reactivity, it is possible to produce images with excellent gradation, fixing properties, and light resistance, and with high density and favorable color reproduction. It is possible to provide the resulting thermal transfer recording material and a thermal transfer recording method that allows efficient recording using the same.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the structural formula of a typical cyan dye according to the present invention. FIGS. 2(A) and 2(B) are explanatory diagrams of the thermal transfer recording method of the present invention. FIG. 3 is a sectional view showing an example of the thermal transfer recording material of the present invention. Antioxidant. OC8HI? 1...Support, 2...Image receiving layer, Image receiving material, 4...Support, 5...6...Thermal transfer recording material, 7...Het, 9...Thermofusible layer, 10. Recording material, 11...Support, ] 2...3. Fist... Heat-sensitive layer, thermal... Heat-sensitive transfer, yellow heat-sensitive layer. 13. Magenta heat-sensitive layer, 14. Cyan Figure 1 heat-sensitive layer, 15. Anti-sticking layer.

Claims (2)

[Claims] (1) A thermal transfer recording material characterized by having a layer containing a dye represented by the following general formula [I] on a support. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [I] [However, in the formula, G represents a chelatable group, and X is 4
Y represents an atomic group that forms an aromatic carbocycle or heterocycle with one nitrogen atom and two carbon atoms, and Y represents an atomic group that forms a five- or six-membered heterocycle with one nitrogen atom and two carbon atoms; Z represents an atomic group which together with two carbon atoms forms an aromatic carbocycle or a heterocycle. ] (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] on a support, and the heat-sensitive transfer recording material is used to convey image information. 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 metal ions.