JP3353427B2 - Thermal transfer ink composition, thermal transfer ink ribbon, and thermal transfer method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer ink composition, a thermal transfer ink ribbon and a thermal transfer method suitable for application to, for example, ink ribbons and photographic paper of video printers.

[0002]

2. Description of the Related Art In recent years, video printers and the like use an ink ribbon in which a disperse dye is dissolved in a hydrophobic high molecular weight material, and apply an image signal to a receiving layer applied and formed on a heat transfer material such as synthetic paper. 2. Description of the Related Art An image is formed by thermally transferring a dye contained in an ink ribbon.

[0003] The disperse dye is used as such a dye because the disperse dye has a hydrophobic property, so that it has good dyeing properties on a material to be thermally transferred and obtains practical sensitivity at the time of transfer. Because you can do it. However, when a disperse dye is used as the dye of the ink ribbon, it is difficult to secure the fixability after printing.

On the other hand, as a dye for dyeing acrylic fibers, a basic dye (so-called cationic dye) having sharpness and high coloring characteristic of basic is known, and is disclosed in US Pat. No. 466.
As disclosed in No. 4671, it has also been proposed to use it as a dye for an ink ribbon.

[0005]

By the way, it is known that cationic dyes show excellent light fastness and wet fastness on an acrylic substrate, but they themselves have a hydrophilic property, and therefore they have a high ink fastness. It is difficult to disperse uniformly and stably in a hydrophobic high molecular weight material such as butyral resin widely used as a ribbon binder, and there is no means for fixing the image during or after image formation. There is.

In order to solve such a problem, the present applicant has previously disclosed in Japanese Patent Application Laid-Open No. Hei 4-299183 a method in which a cationic dye is hydrophobized and used for an ink ribbon, while an interlayer compound capable of ion exchange with the cationic dye is used. A technique in which a binder dispersed in a binder polymer is used for a receiving layer of photographic paper, and a cationic dye transferred to the receiving layer is held in an interlayer compound by ion exchange to fix the dye.

However, in this method, it is necessary to hydrophobize the cationic dye in advance by ion exchange treatment using an organic anionic surfactant or the like, which complicates the manufacturing process of the ink composition and the ink ribbon. There is.

Accordingly, the present invention has been proposed in view of the above-mentioned conventional circumstances, and has been proposed to reduce the complexity of the production process of a cationic dye, which has heretofore been impossible to use as an image forming material of a thermal transfer system. A thermal transfer ink composition and a thermal transfer ink capable of significantly improving sensitivity (density), hue, light resistance, fixability, and the like at the time of image formation with the aim of being applicable without inviting An object of the present invention is to provide a ribbon and a thermal transfer method.

The inventors of the present invention have conducted intensive studies on the achievement of the above-mentioned object, and as a result, if a basic dye is added to an organic high molecular weight material together with a solubilizing agent, the same effect as a disperse dye is obtained. And found to be dispersed or dissolved in the organic high molecular weight compound, and completed the present invention.

That is, the thermal transfer ink composition according to the first invention of the present application contains a cationic dye and an organic high molecular weight substance, and is compatible with both of the cationic dye and the organic high molecular weight substance. The cationic dye is dispersed or dissolved in an organic high molecular weight material by a solubilizer.

A thermal transfer ink ribbon according to a second aspect of the present invention uses the ink composition of the first aspect of the present invention in an ink layer and contains a cationic dye and an organic high molecular weight substance. An ink layer containing a thermal transfer ink composition obtained by dispersing or dissolving the cationic dye in an organic high molecular weight material from a solubilizer having compatibility with both of the cationic dye and the organic high molecular weight material, It is characterized by being formed above.

The cationic dye used in the thermal transfer ink composition of the present invention is a water-soluble dye having an amine salt or a quaternary ammonium group, such as an azo dye, a triphenylmethane dye, an azine dye, an oxazine dye, and a thiazine dye. It has been known. In the present invention, any of these cationic dyes can be used, but specific examples are shown below.
And compounds represented by the following chemical formulas:

[0012]

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[0013]

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[0014]

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[0015]

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[0016]

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[0017]

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[0018]

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[0019]

Embedded image Further, C.I. I. Basic Yellow (CIB
asic Yellow) 21, 36, 67, 73 and the like can also be used. The counter ion of these basic dyes is an inorganic ion. In this case, examples of the inorganic ion include a halogen ion, a perchlorate ion, a borofluoride ion, and a sulfate ion.

As the organic high molecular weight substance, any thermoplastic resin used as a binder resin for this type of ink composition can be used, and examples thereof include polyvinyl butyral, hydroxypropyl cellulose, and ethyl hydroxyethyl cellulose. .

The above cationic dye is usually water-soluble.
Therefore, it is difficult to uniformly disperse even simply mixing with an organic high molecular weight substance. Therefore, in the present invention, a solubilizer that is compatible with both the cationic dye and the organic high molecular weight material is used in combination, and the cationic dye is dispersed or dissolved in the organic high molecular weight material.

The solubilizing agent is a so-called amphiphilic compound which is compatible with both the cationic dye and the organic high molecular weight compound as described above, and preferably has an HLB value of 7.0 or more. This HLB value is determined by the hydrophilic-lipophilic balance (hydr)
The lower the number, the stronger the lipophilicity, and the larger the number, the stronger the hydrophilicity. In the present invention, the solubilizer HL
When the B value is less than 7.0, the hydrophobicity is so strong that compatibility with the cationic dye is lost, and uniform dispersion in the organic high molecular weight substance becomes difficult. The upper limit of the HLB value is not particularly limited, but if it is too large, the compatibility with the organic high molecular weight compound will be insufficient.
It is better to be 0 or less.

The ink ribbon for thermal transfer is produced by forming an ink layer containing the above ink composition on a support. At this time, the ink layer may contain other components, if necessary, such as a transfer temperature regulator, a plasticizer, a binder, and a pigment or dye other than the cationic dye. Further, the solubilizing agent may have both of these functions.

The ink layer is formed by coating on a suitable support. As the support, for example, a polyethylene terephthalate film, a polyamide (so-called nylon) film, a triacetyl cellulose film, a moisture-proof cellophane, a condenser paper, a thin paper, a cloth, and the like can be used.

When performing thermal transfer using the above-described thermal transfer ink composition or thermal transfer ink ribbon, fixing of a basic dye becomes a problem. Therefore, a dispersion of a cationic dye and an ion-exchangeable interlayer compound in a binder polymer is used for the receiving layer of the heat transfer sheet, and the cationic dye transferred to the receiving layer is held in the interlayer compound by ion exchange and fixed. . This is the third invention and the fourth invention of the present application.

Further, a thermal transfer method according to a third invention of the present application includes the ink ribbon of the second invention, an interlayer compound substituted with a cationic dye and an ion-exchangeable ion, and a binder resin. Thermal transfer is performed by using a heat transfer sheet having a receiving layer, wherein the ink layer and the receiving layer are superposed facing each other, and the cationic dye contained in the ink layer is transferred to the receiving layer by heating. It is assumed that.

Examples of the interlayer compound used in the heat transfer sheet include clay minerals having a layered structure and having exchangeable cations between layers. Specific examples include smectite-based clay minerals represented by montmorillonite group minerals. The montmorillonite group mineral has the following general formula (X, Y) pZ4O10 (OH) 2.mH2O. (Wq)
[However, X = Al, Fe (III), Mn (III), Cr
(III), Y = Mg, Fe (II), Mn (II), Ni, Z
n, Li, Z = Si, Al, W = K, Na, Ca, H2 O is interlayer water, and m is an integer. Also, p is 2
-3 and q are 1-3. ] Is represented by the clay mineral.

Here, depending on the combination of X and Y and the difference in the number of substitution, montmorillonite, magnesia montmorillonite, iron montmorillonite, iron magnesia montmorillonite, beidellite, aluminian beidellite, nontronite, aluminian nontronite, saponite, aluminum Many types such as iansaponite, hectorite, and sauconite exist as natural products, and in addition to these natural products, synthetic products in which the OH group in the above formula is substituted with fluorine are also commercially available.

In addition to the above montmorillonite group minerals, sodium silicic mica, sodium teniolite,
Mica group minerals such as lithium teniolite can be used. Kaolinite, talc, pyrophyllite, etc., which have a layered structure but do not have exchangeable cations between layers, are unsuitable. Further, zeolite has an alkali metal ion or an alkaline earth metal ion as an exchangeable cation, but its performance is slightly inferior due to its network-like structure and small pore size.

These intercalation compounds are used in such a manner that organic ions (organic cations) are ion-exchange-bonded between the layers.
Suitable organic ions are organic onium ions such as quaternary ammonium ions and substituted phosphonium ions, for example, alkylphosphonium ions and arylphosphonium ions. However, for example, in the case of a quaternary ammonium ion, the four alkyl groups must have 4 or more, preferably 8 or more carbon atoms. If the number of long-chain alkyls is small, the interlayer distance cannot be sufficiently secured, and there is a possibility that the exchangeability for the dye may be insufficient.

The above-mentioned organic ions increase the interlayer distance between the interlayer compounds and change the interlayers of the interlayer compounds that are originally hydrophilic to hydrophobic by their hydrophobic chains. It plays a role in facilitating compatibility. Therefore, by ion exchange-bonding an organic cation such as a quaternary ammonium ion or a substituted phosphonium ion to the intercalation compound, the ion exchange ability with the cationic dye is imparted, and at the same time, the nonaqueous solvent is swellable.

The intercalation compound which has been given a non-aqueous solvent swelling property by imparting an ion exchange ability with a cationic dye is mixed and dispersed with a binder polymer and applied to a support in a state of being swollen by the binder polymer to form a film. By doing so, a receptor layer is formed, and a heat transfer sheet (so-called photographic paper) is obtained. The support may be any paper, synthetic paper, plastic film, metal plate, metal foil, plastic film on which aluminum is deposited, or the like.

As the binder polymer, a general thermoplastic resin can be widely used, but a substituent which hinders the fixing action, for example, ion exchange between the clay layers is relatively easier than that of a cationic dye. Those containing an ammonium group or the like are not preferred. The amount of the interlayer compound to which the ion-exchange ability is imparted is preferably 5 to 90% by weight based on the solid content of the receptor layer. The lower limit of the addition amount is determined by the fixing ability, and if it is less than 5% by weight, the fixing effect may be insufficient. The upper limit is determined by the practical property of film formation, and if it exceeds 90% by weight, a flexible and good film cannot be formed.

In some cases, the heat transfer sheet preferably has a higher whiteness, and it is one method to add a fluorescent whitening agent to the receiving layer. However, the heat transfer sheet originally has excellent whiteness like synthetic mica. An interlayer compound may be used. As long as the fixability is not impaired, a plasticizer may be added to the receptor layer to control the glass transition point Tg of the binder polymer, and an auxiliary additive may be added for other purposes.

At the time of image formation, the ink layer of the ink ribbon for thermal transfer is brought into contact with the receiving layer of the above-mentioned thermal transfer sheet (printing paper) in a superimposed manner, and the ink ribbon is selected by a thermal head or the like in accordance with an image signal. What is necessary is just to apply a thermal stimulus. For example, when forming a color image,
It is sufficient to use three primary color ink ribbons of Y (yellow), M (magenta), and C (cyan), and perform this operation on each of these ink ribbons. The means for applying the thermal stimulus is not limited to the thermal head,
Any of the thermal transfer systems that have been proposed so far can be employed.

In the above-described thermal transfer, since the cationic dye is hydrophilic, the fixing efficiency is lower than when a hydrophobic cationic dye is used, and unfixed dye tends to remain in the receiving layer. The unfixed dye in the receiving layer is considered to be a molecular aggregate in the form of a pigment in a state of forming a molecule or an aggregate that could not reach the ionic bond site of the intercalation compound. As a result, the frequency of collision with the ion binding site increases,
Complete fixation is obtained.

Therefore, after the transfer of the cationic dye, it is preferable to dissolve the cationic dye and impregnate the receiving layer with a swelling agent which swells the interlayer compound and the binder resin.
However, when the swelling agent dissolves the components of the receiving layer, especially the binder resin, it causes image flow or bleeding, so that a solvent which excels in dye solubility and swells the interlayer compound or the binder resin is preferable. It is.
Therefore, the swelling agent may be appropriately selected depending on the type of the binder resin and the like. For example, when polyvinyl butyral is used as the binder resin, toluene and the like are preferable. In addition, aromatic plasticizers such as phthalates,
Aromatic solvents such as xylene can also be used.

The cationic dye is hydrophilic and does not disperse uniformly in the organic high molecular weight substance as it is. In the present invention, a solubilizer showing compatibility with both the cationic dye and the organic high molecular weight compound is used in combination, and the compatibility with the organic high molecular weight compound of the cationic dye is increased by simply adding the same.
It is uniformly dispersed or dissolved in an organic high molecular weight substance.

Further, it is considered that the above-mentioned solubilizer is also transferred to the receiving layer of the sheet to be transferred (for example, photographic paper) simultaneously with the transfer of the dye, and it is assumed that the transfer of the dye is promoted. The thermal transfer of the cationic dye, which was conventionally difficult to use, is increased to a practical level, and a high-quality image is obtained.

On the other hand, the receptor layer of the heat transfer sheet of the present invention contains an interlayer compound (for example, a smectite clay mineral). The smectite clay mineral has a three-layer structure having a regular octahedral basic skeleton. It has a layered structure composed of repetitions, and has interlayer water and alkali metal ions, which are exchangeable cations, between each layer. This state is shown in FIG.

That is, an untreated smectite clay mineral (for example, synthetic saponite) 1 holds sodium ions 2 as exchangeable cations between layers. The interlayer distance at this time is d1.

The smectite clay mineral 1 is swollen with water to form organic ions (for example, quaternary ammonium ions 3).
Causes quaternary ammonium ions 3 to be taken in between the layers instead of sodium ions 2. At this time, the interlayer distance d2 is larger than the interlayer distance d1 of the untreated smectite clay mineral, and the ion exchange ability with the cationic dye is provided. This state is shown in FIG.

When the cationic dye is heat-transferred to the receiving layer containing the smectite clay mineral in this state, the cationic dye becomes compatible with the receiving layer and also enters each layer by the action of the solubilizer. Then, ion exchange occurs between the quaternary ammonium ion 3 and the cationic dye 4, and the cationic dye 4 is taken between the layers of the smectite clay mineral 1 as shown in FIG. The cationic dye 4 incorporated between the layers of the smectite-based clay mineral 1 forms an ionic bond with the smectite-based clay mineral 1, and is firmly fixed to the receiving layer.

[0043]

Embodiments of the present invention will be described below in detail with reference to specific experimental results.

Example 1 An azo-based cationic dye for dyeing acrylic fibers (manufactured by Nippon Kayaku Co., Ltd., trade name: Kayacryl Red GR) subjected to Soxhlet extraction with ethanol and excluding additives such as sodium sulfate
Using L), an ink ribbon for thermal transfer was produced in the following manner. The azo cationic dye used here was C.I.
I. Basic Red (CI Basic Red)
46, and its structure is as shown in Chemical Formula 12.

That is, a 6 μm-thick polyethylene terephthalate (PET) film provided with a heat-resistant lubricating layer 5 on one side is used as a support 6, and the support 6 is provided on the side opposite to the side on which the heat-resistant lubricating layer 5 is provided. The surface was coated with a thermal transfer ink composition having the following composition at a rate of 25 g / m @ 2 by wire bar coating and dried. As a result, as shown in FIG. 4, an ink ribbon 8 for thermal transfer having an ink layer 7 having a thickness of about 1 μm on a support (PET film) 6 was obtained.

Ink composition for thermal transfer 1 part by weight of cationic dye Binder resin polyvinyl butyral (6000-CS, manufactured by Denki Kagaku Kogyo Co., Ltd.) 2 parts by weight Solubilizer polyoxyethylene alkylphenyl ether (NP-20, manufactured by Nikko Chemical Co., Ltd.) HLB value 3.5) 2 parts by weight Methyl ethyl ketone / toluene (1/1 weight ratio) 24 parts by weight On the other hand, a heat transfer sheet was prepared in the following manner. That is, first, a solution containing a vinyl chloride-acryl copolymer (manufactured by Sekisui Chemical Co., Ltd., Eslec E-C130) at the following weight ratio was prepared to obtain a coating stock solution 1.

Composition of Coating stock solution 1 Vinyl chloride-acrylic copolymer 100 parts by weight Silicon oil (manufactured by Dow Corning Silicone Toray Co., Ltd .: SF8427) 2 parts by weight Methyl ethyl ketone / toluene (1/1 weight ratio) 500 parts by weight The quaternary ammonium-substituted montmorillonite was ultrasonically dispersed and swelled in a mixed solvent in the following weight composition to obtain a coating stock solution 2.

Composition of Coating stock solution 2 Tetra-n-octylammonium-substituted montmorillonite 50 parts by weight Methyl ethyl ketone / toluene (1/1 weight ratio) 500 parts by weight The method for producing tetra-n-octylammonium montmorillonite is as follows. . 20 g of montmorillonite is dispersed in 1 liter of water and allowed to swell,
After adding an equal amount of ethanol to this dispersion, tetra-n bromide dissolved in 200 cc of ethanol was stirred.
10.9 g (20 mg equivalent) of octyl ammonium was added dropwise. As a result, aggregation and sedimentation of the particles occurred. After leaving this dispersion liquid for one week, the precipitate was filtered off and washed with a large amount of ethanol to remove unreacted quaternary ammonium salts. Subsequently, the washed precipitate was dried under reduced pressure at room temperature to obtain an off-white powder. The (001) plane distance of this powder, that is, the interlayer distance, was measured to be 19.6 ° by powder X-ray diffraction analysis, and was extended 9.8 ° from the initial (untreated) montmorillonite plane distance of 9.8 °. .

The above-mentioned coating stock solutions 1 and 2 were mixed at an equal weight ratio, and further dispersed by stirring with a ball mill to obtain a coating solution. This coating solution was applied to a 125 μm-thick white polyester film using a doctor blade, and dried at 60 ° C. for 30 minutes under reduced pressure. By this operation, a heat transfer sheet having a film having a thickness of about 5 μm as a receiving layer when dried was produced. Next, in order to improve the surface properties, a heat / pressure treatment was applied to obtain a glossy pale yellow transparent receiving layer.

The ink ribbon for thermal transfer obtained by the above-mentioned process was mounted on a ribbon cassette (not shown), and was printed on the above-mentioned thermal transfer sheet using a color video printer (CVP-G500, manufactured by Sony Corporation). However, an image having a good cyan hue and rich in gradation was obtained. The highest concentration (OD) was 1.2. Further, toluene (a swelling agent) was sprayed on this image, left for several minutes, and excess toluene was wiped off. When the fixing rate of the image was determined by the solvent immersion test method by this treatment, it was found to be about 40%
From about to 98%.

The solvent immersion test method is as follows. A portion of the recorded image was extracted at room temperature with methyl ethyl ketone /
It was put into toluene (1/1 weight ratio: solvent used for preparing the receiving layer) and left for 15 hours. The ratio of the D value (reflection density) was calculated as the fixing rate.

Fixing ratio = (OD value after charging) / (OD value before charging) × 100 (%) For comparison, the solubilizing agent was removed from the above-described ink composition for thermal transfer. An ink composition having the above composition was prepared, an ink ribbon for thermal transfer was prepared using the ink composition, and an image was formed by the same method. As a result, the maximum density of the image was 0.3.
In addition, the presence of dye solids, which indicate insufficient dissolution or dispersion of the dye, is recognized in the thermal transfer ink ribbon and the printing portion of the receiving layer, and the image quality becomes practical in addition to the highest density. It was poor.

Example 2 A purified oxazine-based cationic dye (CI Basi
c Blue 75: The structural formula is shown in Chemical formula 9. ) (Made by Hodogaya Chemical Industry Co., Ltd., trade name Aizen Cathilon Blu)
e 3GLH) to prepare an ink ribbon for thermal transfer with three kinds of binder resins in the same manner as in Example 1, and print on a thermal transfer sheet comprising a receiving layer having the following composition to improve the color density. Examined. Table 1 shows the results.

A heat transfer sheet was prepared with a solution containing the vinylidene chloride-acrylonitrile copolymer (Aldrich's reagent) in the following weight ratio,
The coating stock solution 1 was used.

Composition of Coating stock solution 1 Copolymer 100 parts by weight Silicon oil (manufactured by Toray Dow Corning Silicone Co., Ltd .: SF8427) 2 parts by weight Methyl ethyl ketone 500 parts by weight Also, a mixed solvent of quaternary ammonium-substituted smectite having the following weight composition The mixture was ultrasonically dispersed and swollen to obtain a coating stock solution 2.

Composition of Coating stock solution 2 Tetra-n-decylammonium substituted synthetic smectite 50 parts by weight Methyl ethyl ketone 500 parts by weight The method for producing tetra-n-decylammonium substituted smectite is as follows. 20 g of synthetic saponite (Kunimine Industries, trade name: Smecton SA) is dispersed in 1 liter of water and allowed to swell, an equal amount of ethanol is added to this dispersion, and 200 c is added while stirring.
13.2 g (20 mg equivalent) of tetra-n-decylammonium bromide dissolved in ethanol of c was added dropwise. When left for one week, granular coagulation and sedimentation occurred, but the sedimentation speed was slower than that of synthetic saponite.

The precipitate was filtered from the dispersion and washed with a large amount of ethanol to remove unreacted quaternary ammonium salts. Subsequently, the washed precipitate was dried under reduced pressure at room temperature to obtain a pure white powder. The spacing between the (001) faces of this powder,
That is, the interlayer distance was 21.9 by powder X-ray diffraction analysis.
Measured to be 6 、, and the interplanar spacing 1 of untreated synthetic saponite
It was 9.32 ° longer than 2.64 °.

Then, these coating stock solutions 1 and 2
Were mixed at an equal weight ratio, and further dispersed by stirring with a ball mill to obtain a coating solution. This coating solution was applied on a synthetic paper having a thickness of 60 μm using a doctor blade, and dried at 60 ° C. under reduced pressure for 30 minutes. By this operation, the film thickness when dried is about 5
A heat transfer sheet having a μm film as a receiving layer was prepared. Next, in order to improve the surface properties, a heat / pressure treatment was applied to obtain a glossy colorless transparent receiving layer.

[0059]

[Table 1] As can be seen from the results of Table 1, when hydroxypropylcellulose (HPC) was used as the binder and ethyl alcohol (EtOH) was used as the solvent, the maximum concentration was 0.76 when no solubilizing agent was added. On the other hand, when diethylhexylsulfosuccinate monosodium (AOT) or n-dodecylbenzenesulfonic acid (n-DBS) is added as a solubilizing agent, 1.44 and 1.20 are sufficient for practical use. It has become something.

Next, looking at the case where ethylhydroxyethyl cellulose (EHEC) was used as the binder and EtOH was used as the solvent, the maximum concentration was 0.56 when no solubilizing agent was added, whereas the maximum concentration was 0.56 when AOT was added. When the addition amount was increased to 1.0, 1.5, and 2.0 in the addition amount / dye ratio, the maximum densities were 1.55 and 1.6, respectively.
It shows a tendency to increase to 4, 1.70, which is sufficient for practical use.

Further, when the case where polyvinyl butyral (6000C-S) was used as the binder and a mixed solvent of methyl ethyl ketone / toluene was used as the solvent, when the solubilizing agent was not added, the maximum concentration was 0.37. And n-DBS, sodium n-dodecyl sulfate (D
When S-Na) and polyoxyethylene alkylphenyl ether (NP-20) were added, 1.1
It shows high concentrations of 0, 0.74 and 0.90.

Example 3 An ink ribbon for thermal transfer was prepared in the same manner as in Example 2 using the cationic dye shown in Chemical Formula 11, and was printed on a heat-transferred sheet in the same manner as in Example 2 to improve the color density. Examined. Table 2 shows the results.

[0063]

[Table 2] Example 4 Using the cationic dye shown in Chemical formula 14, an ink ribbon for thermal transfer was produced in the same manner as in Example 2, and printing was carried out on the same heat-transfer sheet as in Example 2 to examine the effect of improving the color density. Table 3 shows the results.

[0064]

[Table 3] Example 5 Using the cationic dye shown in Chemical formula 15, an ink ribbon for thermal transfer was produced in the same manner as in Example 2, and printing was performed on the same heat-transfer sheet as in Example 2 to examine the effect of improving the color density. Table 4 shows the results.

[0065]

[Table 4] Example 6 An ink ribbon for thermal transfer was produced in the same manner as in Example 2 using the cationic dye shown in Chemical Formula 16 and three kinds of solubilizers, and was printed on a heat-transfer sheet similar to that in Example 2. The effect of improving the color density was examined. Table 5 shows the results.

[0066]

[Table 5] Example 7 An ink ribbon for thermal transfer was prepared using the cationic dye shown in Chemical formula 10 in the same manner as in Example 2, and printing was performed on the same heat-transferred sheet as in Example 2 to examine the effect of improving the color density. Table 6 shows the results.

[0067]

[Table 6] Example 8 Using the cationic dye shown in Chemical Formula 13, an ink ribbon for thermal transfer was produced in the same manner as in Example 2, and printing was performed on the same heat-transfer sheet as in Example 2 to examine the effect of improving the color density. Table 7 shows the results.

[0068]

[Table 7] Example 9 C.I. I. Using Basic Yellow 21, a thermal transfer ink ribbon was produced in the same manner as in Example 2.
The image was printed on the same heat-receiving sheet as in Example 1 to examine the effect of improving the color density. Table 8 shows the results.

[0069]

[Table 8] In any of the examples, a high color density was obtained when a solubilizing agent was used in combination.

[0070]

As is apparent from the above description, according to the present invention, a cationic dye can be used as a thermal transfer type image forming material, and an image having excellent sensitivity (density), hue, and light fastness can be obtained. Formation is possible. At this time, it is not necessary to previously perform a hydrophobic treatment on the cationic dye, and it is only necessary to add a solubilizer, so that the manufacturing process of the thermal transfer ink composition or the thermal transfer ink ribbon can be simplified, It is very advantageous in manufacturing.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing the structure of saponite.

FIG. 2 is a schematic diagram of saponite substituted with a quaternary ammonium ion.

FIG. 3 is a schematic view of saponite ion-exchanged with a cationic dye.

FIG. 4 is an enlarged sectional view of a main part showing an example of a thermal transfer ink ribbon.

[Explanation of symbols]

 4 ... Cation dye 6 ... Support 7 ... Ink layer 8 ... Ink ribbon for thermal transfer

────────────────────────────────────────────────── ─── Continuation of front page (72) Motohiro Mizumachi Inventor of Sony Corporation, 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo (56) References JP-A-4-299183 (JP, A) JP-A-Hei 4-299175 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B41M 5/38-5/40

Claims (7)

(57) [Claims] 1. A and also contains the cationic dye and the organic high polymer, disperse the cationic dye solubilizers having compatibility with both of these cationic dyes and organic high polymer is in the organic high polymer or An ink composition for thermal transfer, which is dissolved. 2. The ink composition for thermal transfer according to claim 1, wherein the solubilizing agent is an amphiphilic compound. 3. The thermal transfer ink composition according to claim 2, wherein the amphiphilic compound has an HLB value of 7 or more. 4. A cationic dye cationic dye shown in Chemical Formula 1 or Formula 8 below, or C., I. 2. The thermal transfer ink composition according to claim 1, wherein the ink is at least one selected from Basic Yellow 21, 36, 67 and 73, and a counter ion thereof is an inorganic ion. Embedded image Embedded image Embedded image Embedded image Embedded image Embedded image Embedded image Embedded image 5. An ink ribbon for thermal transfer, wherein an ink layer containing the ink composition for thermal transfer according to claim 1 is formed on a support. 6. A thermal transfer sheet having an ink layer of the thermal transfer ink ribbon according to claim 5 and a receptor layer containing an interlayer compound substituted with ions capable of ion exchange with a cationic dye and a binder resin. A thermal transfer method, wherein the receiving layer is superposed on the receiving layer, and the cationic dye contained in the ink layer is transferred to the receiving layer by heating. 7. The receiving layer is impregnated with a swelling agent which dissolves the cationic dye and swells the intercalation compound and the binder resin after transferring the cationic dye.
The thermal transfer method as described.