JP2000309168A - Thermal transfer recording material - Google Patents

Abstract

(57) [Summary] [PROBLEMS] Used in a non-contact type dye flying type thermal transfer recording method, preventing occurrence of kogation, realizing excellent resolution and in-pixel gradation, and improving recording performance for a long time. Provided is a cyan thermal transfer recording material that can be held. SOLUTION: This thermal transfer recording material is guided by a capillary phenomenon to a transfer portion having a porous structure, changes its state by heating, and is transferred to an object to be transferred opposed to the transfer portion. A) a thermal transfer recording material containing a dye represented by Embedded image (Wherein, rings A and B may further have a substituent,
R ¹ is an alkyl group having 4 to 12 carbon atoms which may have a substituent, R ² is a branched alkyl group having 4 to 12 carbon atoms which may have a substituent, R ¹ ≠ R ² . )

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a thermal transfer recording method,
For example, a thermal transfer recording material used in a full-color image recording method in which a recording liquid containing a dye flies from a recording unit by selective heating according to image information and is transferred to an opposing photographic paper, particularly a recording liquid containing a cyan dye It is about.

[0002]

2. Description of the Related Art In recent years, as colorization of video cameras, computer graphics, and the like has progressed, the need for colorization of hard copies has rapidly increased. On the other hand, a color hard copy system such as a sublimation thermal transfer system, a melt thermal transfer system, an ink jet system, an electrophotographic system, and a heat-developed silver salt system has been proposed. Among these recording methods, methods for easily outputting high-quality images with a simple apparatus can be broadly classified into a dye diffusion thermal transfer method (sublimation thermal transfer method) and an ink jet method.

Among these recording methods, according to the dye diffusion thermal transfer method, an ink ribbon or sheet in which an ink layer in which a high concentration of transfer dye is dispersed in an appropriate binder resin is applied, and the transferred dye is A transfer medium such as photographic paper coated with a dyeing resin that receives the ink is brought into close contact with a certain pressure, and heat is applied according to the image information from a thermal recording head located on the ink sheet, and the ink sheet is The transfer dye is thermally transferred according to the amount of heat applied to the dye receiving layer.

The above operation is performed by subtracting the three primary colors of subtraction,
The so-called dye diffusion thermal transfer method is characterized by obtaining a full-color image having continuous gradation by repeating each of the image signals separated into yellow, magenta, and cyan. It is attracting attention as an excellent technology for obtaining high-quality images comparable to silver halide color photographs.

FIG. 6 is a schematic front view of a main part of such a thermal transfer type printer. A thermal recording head (hereinafter referred to as a thermal head) 31 and a platen roller 33 face each other,
Between these, the ink layer 32 is formed on the base film 32b.
a and a recording paper (transfer medium) 30 provided with a dyeing resin layer 30a on a paper 30b, which are pressed against the thermal head 31 by a rotating platen roller 33. To run.

The ink (transfer dye) in the ink layer 32a selectively heated by the thermal head 31 is used.
Is transferred to the dyed resin layer 30a of the transfer object 30 in the form of dots, and thermal transfer recording is performed. In such thermal transfer recording, a serial system in which a thermal head scans in a direction perpendicular to the traveling direction of the recording paper 30 or a single thermal head fixed in a direction perpendicular to the traveling direction of the recording paper is arranged. A line system is adopted.

However, this method is disadvantageous in that a large amount of waste is generated due to disposable use of the ink sheet and high running cost is a major drawback, and its spread is hindered.
This is the same in the fusion heat transfer system. As described above, the conventional thermal transfer method has high image quality, but the running cost is high because the dedicated photographic paper and the disposable ink ribbon or sheet are used.

[0008] Although the heat-developable silver salt method has a high image quality, the running cost and the apparatus cost are also high because dedicated photographic paper and disposable ink ribbons or sheets are used. On the other hand, the ink jet method is described in JP-B-61-599.
No. 11 and Japanese Patent Publication No. 5-217, etc.,
According to image information, electrostatic suction method, continuous vibration generation method (piezo method), thermal method (bubble jet method)
In this method, a small droplet of the recording liquid is made to fly from a nozzle provided in a recording head and adhere to a recording member, thereby performing recording.

Therefore, there is almost no waste as in the case of using an ink sheet or the like, and the running cost is low. Recently, the thermal method has been widely used because it can easily output a color image. However, in the ink-jet method, the density gradation in the pixel is difficult in principle, such as that obtained by the dye diffusion thermal transfer method.
It is difficult to reproduce a high-quality image comparable to a silver halide photograph in a short time.

That is, in the conventional ink jet, since one droplet of ink forms one pixel, in-pixel gradation is difficult in principle, and a high-quality image cannot be formed. Attempts have been made to express the pseudo-gradation by the dither method using the high resolution of the ink jet, but the image quality equivalent to that of the sublimation type thermal transfer system cannot be obtained, and the transfer speed has been remarkably reduced.

On the other hand, the electrophotographic method has a low running cost and a high transfer speed, but has a high apparatus cost. As described above, there is no recording method that satisfies all requirements such as image quality, running cost, apparatus cost, and transfer time. Recently, a new recording method that solves these problems has been proposed (see Japanese Patent Application Laid-Open No. 7-89107). That is, the recording liquid is guided to a transfer portion having a porous structure by a capillary phenomenon, and heated by a suitable heating means such as a laser beam.
This is a non-contact type dye flying type thermal transfer recording system in which a recording liquid is vaporized or a mist having a diameter of 20 μm or less is generated and transferred to a photographic paper which is arranged to face through a gap of 10 to 1000 μm. .

In such a non-contact type thermal transfer recording system, the surface area of the heating section (transfer section) is increased by the above-mentioned porous structure, and the recording liquid is constantly supplied to the recording liquid heating section by capillary action, and is supplied there. In this state, a portion of the recording liquid is evaporated by selectively applying a heat amount according to the recording information by a heating means (for example, a laser beam) in this state, and an electric power generated by a color video camera or the like is obtained. The amount of recording material corresponding to the recording information corresponding to a typical image can be transferred to the recording medium by converting it into minute vapor or droplets and transferred onto the recording medium.

Accordingly, a large number of liquid droplets having a smaller size can be formed as compared with the known ink jet method, and the number of generated liquid droplets can be freely controlled according to the heating energy corresponding to the information recorded in the recording liquid heating section. Since it is possible to perform multi-value density gradation, it can be equivalent to a silver halide image or
It is possible to obtain a recording (for example, a full-color image) having a higher image quality.

Further, since it is a thermal transfer recording system, it has the above-mentioned features such as miniaturization, easy maintenance, quickness, high quality of image, high gradation, and the like. Dyes suitable for this thermal transfer recording method are described in JP-A-8-244366 and
Anthraquinone dyes are proposed in US Pat. No. 5,258,583 and JP-A-9-39421. However,
It has been found that this thermal transfer recording system has the above-mentioned excellent features and also has a problem to be improved. That is, if the transfer is repeated by this method, charred (decomposed products of the dye) accumulates in the transfer portion, and the ejection holes are clogged.
So-called kogation occurs. As a result, the flying state of the recording material fluctuates, and the recording performance tends to deteriorate.

[0015]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a liquid crystal display having excellent resolution and pixel resolution while simultaneously utilizing the advantages of both the above-described thermal transfer system and the ink-jet system, and at the same time, eliminating those drawbacks, especially the problem of kogation. It is an object of the present invention to provide a thermal transfer recording material that can realize an inner gradation and maintain recording performance for a long time.

[0016]

The present inventors have studied various anthraquinone dyes and found that kogation as described above occurs due to insufficient heat resistance of the dye used as a recording material. By using an anthraquinone-based dye having a specific substituent group, the heat resistance of the dye is sufficient, kogation can be greatly reduced, the life of the head can be extended, and the solubility and heat resistance of the dye in a solvent can be improved. Are found to be improved, and the present invention has been achieved.

That is, the present invention relates to a thermal transfer recording material which is guided to a transfer portion having a porous structure by a capillary phenomenon, changes its state by heating, and is transferred to an object to be transferred facing the transfer portion, The gist of the present invention is a thermal transfer recording material containing a dye represented by the following general formula (I).

[0018]

Embedded image

(Wherein rings A and B may further have a substituent, and R ¹ has 4 carbon atoms which may have a substituent.
And R ² is a branched alkyl group having 4 to 12 carbon atoms which may have a substituent, and R ¹ ≠
R ² . )

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
In the dye represented by the general formula (I) of the present invention, the rings A and B may further have a substituent, and the group which may be substituted may be an alkyl group, an alkoxy group, a cycloalkyl Group, aryl group and the like. R ¹ in the general formula (I) has 4 carbon atoms which may have a substituent.
To 12, preferably an alkyl group having 4 to 8 carbon atoms, wherein the substituent is a hydroxyl group, an alkoxy group, an acyloxy group, an alkoxyalkoxy group, an alkoxycarbonyl group, a heterocyclic group-containing group, an alkenyloxy group, an aryloxy group And the like. Among them, R ¹ is preferably an unsubstituted alkyl group, specifically, i-butyl group, i-amyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, n
-Dodecyl group and the like, and particularly, i-butyl group, n
A -hexyl group or an n-octyl group is preferred in terms of solubility of the dye in a solvent and heat resistance.

In the general formula (I), R ² represents an optionally substituted C 4-12, preferably C 4,
~ 8 branched alkyl groups, and the substituent of R ² is
Same as the substituents of the above R ¹ can be exemplified. Among them, R ² is preferably an unsubstituted branched alkyl group having 5 to 9 carbon atoms from the viewpoint of the sensitivity of the dye, and more preferably an alkyl group branched at the β-position. Among them, R ² is i-butyl,
Preferred are i-amyl, 2-ethylhexyl, 1-ethyl-n-propyl and 1-n-propyl-n-butyl, and particularly preferably a 2-ethylhexyl group.

In the present invention, R ¹ and R ² described above are different alkyl groups, whereby the solubility of the dye in a solvent and the heat resistance are improved. Specific examples of dyes usable in the present invention are shown in Table 1 below.

[0023]

[Table 1]

The thermal transfer recording material of the present invention is, specifically,
This is a liquid recording material which is vaporized by heating or generates a mist having a diameter of 20 μm or less, and is transferred onto an object to be transferred opposed to each other via a gap of 10 to 1000 μm. By non-contact transfer through such a gap,
As described above, it has high image quality and immediacy, can be compact and lightweight, can be transferred to plain paper without generating waste, and has low power consumption and low running cost. Color printing can be performed.

Further, the above-mentioned porous structure has a function of supplying and holding the recording material to the transfer portion by its capillary action, and in particular, has a side or diameter of 0.2 to 3 μm and a diameter of 1 to 1 μm.
It preferably has a height of 5 μm. In this case, 0.2
Fine columns having a side or diameter of 1 to 3 μm and a height of 1 to 15 μm are arranged in three or more rows at intervals of 0.3 to 3 μm and 3
It is preferable that the porous structure is formed by arranging the rows or more.

Such a porous structure (for example, a concavo-convex structure composed of a large number of columnar bodies) has the following three remarkable effects. That is, the first effect is that the recording liquid can be spontaneously supplied to the recording portion by the capillary phenomenon due to the large surface area formed by the above-mentioned uneven structure.
The second effect is that the surface tension of the liquid generally decreases as the temperature increases, so that when the recording liquid is heated, the surface tension at the center of heating of the recording liquid is lower than the surface tension at the outer periphery thereof, and the recording liquid at the center part is reduced. However, since the heating portion has the above-described uneven structure, the movement of the recording liquid to the outer peripheral portion can be suppressed, and a decrease in transfer sensitivity can be prevented.

The third effect is that a large number of concave portions in the concave-convex structure of the recording portion each act as a fine ejection portion, so that a very small number of recording liquids corresponding to the amount of heat applied to the recording portion are formed. Droplets are ejected, fly into the space, and are adsorbed on the opposing recording medium such as photographic paper. Using this principle,
The in-pixel gradation that was impossible with the ordinary ink-jet method was enabled.

That is, by providing the above-mentioned porous structure (concavo-convex structure) in the heating section, the surface area is increased, and the recording liquid can be constantly supplied to the recording liquid heating section by capillary action and held there. In this state, a heating means (for example, a laser beam) is used to selectively apply heat in accordance with the recording information, thereby evaporating a part of the recording liquid to cause an increase in pressure, and an electric power generated by a color video camera or the like. The recording material in an amount corresponding to the recording information corresponding to the typical image is converted into fine droplets, transferred to the recording medium, and transferred onto the recording medium.

In this case, a large number of droplets having a small size can be formed as compared with the known ink jet system, and the number of droplets generated can be freely adjusted according to the heating energy corresponding to the information recorded in the recording liquid heating section. Since control can be performed, multi-value density gradation can be achieved, and recording (for example, a full-color image) having image quality equal to or higher than that of a silver halide image can be obtained.

Therefore, using a head having a special structure capable of thermally transferring very fine recording droplets on demand, at least 128 or more density gradations within one pixel per color. An ink jet system capable of expressing can be realized. To form such a porous structure, for example, a method of laminating porous alumina having an average particle size of 0.1 to 2 μm to a thickness of 5 to 20 μm, an average particle size of 0.5 to
A method of laminating 3 μm glass beads to a thickness of 5 to 20 μm, a method of growing a large number of silicon whiskers having an average diameter of 0.5 to 2 μm and a height of 2 to 10 μm on a substrate at an interval of 1 to 3 μm, and the like. Can be manufactured.

However, in order to precisely control the transfer amount, a semiconductor processing technique such as a reactive ion etching (RIE) method or a powder beam etching method is used. Height 1-15μ
A structure in which fine columns made of glass or silicon having a size in the range of m are regularly arranged in three or more rows and three or more columns at intervals of 0.5 to 10 μm is preferable.

Further, a porous structure having a heat resistance of 300 ° C. or more is formed, and the generated droplets are supplied to
It is preferable to fly the recording medium facing the recording medium with a gap of 1000 μm. Such a porous structure,
Although it has the above-mentioned excellent action, its small size makes it possible to prevent deterioration due to heating of the recording material during recording (particularly repetitive recording), for example, decomposition products, from adhering to the porous structure and to prevent clogging. And tends to impair its effect.

However, the dye of the general formula (I) used in the recording material of the present invention has sufficient heat resistance to heating and hardly causes kogation due to decomposition products. Even at times, the action of the porous structure can be maintained and effectively exerted. When the recording material of the present invention is heated to 300 ° C. or more, 90% by weight or more is vaporized and the residue is 10% by weight or less, and the dye (dye) is 5% at 50 ° C. or less. % Or more of a solvent having a boiling point of 150 ° C. or higher to be dissolved or dispersed.

The solvent used in the recording liquid should be one that sufficiently dissolves or disperses the above-mentioned dye and has a boiling point of 150 ° C. or higher. This is because the above-mentioned porous structure has a large surface area, and if the boiling point is not higher than 150 ° C., the solvent evaporates or volatilizes to dry the recording portion, and the recording liquid concentration fluctuates, and the recording performance changes. Is to deteriorate.

In particular, the solvent has a melting point of 50 ° C. or less, a boiling point in the range of 150 ° C. to 400 ° C., and is preferably colorless. When the melting point exceeds 50 ° C., the melting point of the dye is generally 100 ° C. or higher. Therefore, the recording liquid prepared by mixing the dye and the solvent solidifies within a range from room temperature, which is the non-transferred recording part temperature, to 50 ° C. Easier to do.
If the boiling point is lower than 150 ° C., the recording portion is exposed to the atmosphere, so that only the solvent tends to volatilize from the recording liquid. When the boiling point is 400 ° C. or higher, the efficiency of vaporization is low, and the transfer sensitivity tends to decrease.

The solvent preferably has a molecular weight of 450 or less. If the molecular weight is too high, the expansion rate during vaporization is low, and the transfer sensitivity tends to decrease. Further, a solvent having a residual ratio of 0.01% by weight or less when heated to 200 ° C. in air is preferable. The solvent is PPC paper (plain paper),
It is preferable to have the property of being spontaneously absorbed by fibers such as art paper from the viewpoint of transfer to plain paper.

The solvent is 5% by weight of the above dye at 50 ° C. or less.
As described above, especially in order to dissolve 10% by weight or more, the value of the solubility parameter of the solvent at 25 ° C. (as defined by JH Hildebrand) is preferably in the range of 7.5 to 10.5. preferable. Further, it is preferable that the flash point is 150 ° C. or higher, the toxicity to the human body is low, and the color is colorless. When the solubility parameter exceeds 10.5, the solubility of the dye becomes low, and the reproducibility of the transfer sensitivity is liable to deteriorate due to the adsorption of water vapor in the air. When the solubility parameter is less than 7.5, the solubility of the dye tends to be low.

Specifically, di- and trialkyl esters of aromatic carboxylic acids such as phthalic acid and trimellitic acid; succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, dodecandioic acid Dialkyl esters of aliphatic dicarboxylic acids such as; octanoic acid, nonanoic acid, decanoic acid, dodecanoic acid, alkyl esters of aliphatic monocarboxylic acids such as myristic acid; diethylene glycol, triethylene glycol,
Tetraethylene glycol, dipropylene glycol,
Dialkyl ethers of glycols such as tripropylene glycol; ethylene glycol, propylene glycol, 1,4-butanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, 2,2,4-trimethyl Monoalkyl ether monoalkyl esters of glycols such as pentanediol; ethylene glycol, propylene glycol,
1,4-butanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, 2,
Examples thereof include dialkyl esters of glycols such as 2,4-trimethyl-pentanediol; and aromatic hydrocarbons such as alkylbenzene and alkylnaphthalene.

The alkyl group of the alkyl ester of the carboxylic acids is substituted with a linear or branched unsubstituted alkyl group or a heterocyclic group such as an alkoxy group, an aryloxy group, an aryl group or a tetrafurfuryl group. An alkyl group having 1 to 20 carbon atoms is suitable. Further, as the alkyl group of the above-mentioned alkyl esters and alkyl ethers of glycols, a linear or branched one having about 1 to 20 carbon atoms is suitable.

Particularly preferred solvents are dibutyl phthalate, dioctyl phthalate, diethyl sebacate, dibutyl sebacate, dioctyl sebacate, di (2-ethylhexyl) sebacate, diethyl azelate,
Dibutyl azelate, dioctyl azelate, di (2-ethylhexyl ester) azelate, ethyl decanoate, propyl decanoate, butyl decanoate, amyl decanoate, hexyl decanoate, heptyl decanoate, Octyl decanoate, (2-ethylhexyl) decanoate, decyl decanoate, ethyl octanoate, propyl octanoate, butyl octanoate, amyl octanoate, hexyl octanoate, heptyl octanoate, octane octane Acid octyl ester, octanoic acid (2-ethylhexyl) ester, octanoic acid decyl ester, octanoic acid (2-butoxyethyl) ester,
Octanoic acid (2-phenoxyethyl) ester, octanoic acid (2-phenylethyl) ester, octanoic acid tetrahydrofurfuryl ester, dodecanoic acid butyl ester, myristic acid butyl ester, diethylene glycol dibutyl ether, triethylene glycol dimethyl ether, triethylene glycol di Butyl ether,
Tetraethylene glycol dimethyl ether, diethylene glycol monobutyl ether acetate, 2,2
4-trimethyl-pentanediol diisobutyl ester, acetyl tributyl citrate and the like.

The dyes used in the conventional ink-jet method generally contain many acid dyes, which are hydrophilic and flow on the recording paper when they adhere to the recording paper.
It is poor in water resistance, hardly develops color, and easily generates kogation due to self-decomposition due to heat during recording. On the other hand, since the above-mentioned cyan dye does not cause such a phenomenon, the cyan dye adheres well to recording paper and develops color more than enough, and kogation hardly occurs.

Further, when the above-mentioned solvent is used in combination with the cyan dye, the solvent has good permeability into the recording paper, can sufficiently adhere the dye, and It also acts as a color-forming aid for coloring. Therefore, when this recording liquid is used, transfer to PPC paper is possible, and a high-quality image can be formed. Further, the dye concentration of the recording liquid was conventionally at most 5% by weight, but in the recording liquid composed of the above combination, the solvent amount can be set in a wide range of 50 to 90% by weight, and the dye concentration is 10% by weight. As described above, the image density can be improved.

The transfer head using the recording material of the present invention may comprise a recording section provided with a heating means, an ink tank for storing recording liquid, and a recording liquid passage connecting the recording section and the ink tank. The entire transfer head can be heated to 50 ° C. in order to adjust the viscosity of the recording liquid. In order to shorten the transfer time, two recording units are provided on one recording head.
More than one can be provided. The recording liquid consumed in the recording unit can be continuously supplied to the recording unit through the recording liquid passage.

The heating means is a heating element such as a resistance heater,
A laser whose output changes in accordance with recording information, a combination of a laser and a laser light absorber (photothermal converter) provided in a recording unit, or the like can be used. When a semiconductor laser is used as a laser, a small and lightweight head can be configured with high controllability. The resistance heater is manufactured by directly attaching a conductive substance such as polysilicon on the recording unit.

The printing paper which can be used for the transfer of the recording material of the present invention is plain paper such as PPC paper, high-quality paper such as art paper, etc. In order to obtain a high quality image having particularly high gradation and density. In addition, a special paper prepared by applying polyester, polycarbonate, acetate, epoxy resin, polyvinyl chloride, or the like on a base paper as a resin for coloring a dye can also be used. In order to improve the storage stability of the obtained image, it is effective to laminate a resin film on the photographic paper after transfer.

In order to achieve multicolor recording (especially full color) using the recording material of the present invention, a recording liquid containing a dye exhibiting one of the three primary colors of subtractive color mixing, A recording liquid containing at least one kind of dye exhibiting three subtractive primary colors is selectively heated. For example, this operation is decomposed into yellow (Y), magenta (M), and cyan (C). Full colorization can be achieved by repeating each of these image signals.

With the recent demand for high performance of printing technology, it is required to carefully select the color tone of each of Y, M, and C in full-color printing.
It is also excellent in that a beautiful color tone satisfying the demand can be obtained. The dye of the present invention is preferable because it can obtain a beautiful cyan color tone having a peak wavelength of 650 to 680 nm in a reflection spectral spectrum when transferred to a recording paper coated with a base paper coated with a polyester resin. When such a good cyan (C) dye of the present invention is combined with a yellow (Y) dye and a magenta (M) dye, the yellow (Y) dye is represented by the following general formula (II) and has a molecular weight of 400: It is preferred to combine the following dyes.

[0048]

Embedded image

(Wherein C is p which may have a substituent)
R ³ and R ⁴ are each a hydrogen atom, a substituted or unsubstituted alkyl or alkenyl group, a cycloalkyl group, or a substituted or unsubstituted phenyl group. R ³ furthermore cooperates with the nitrogen atom bonded to the phenylene group C and phenylene group C may form a heterocyclic 5- or 6-membered heterocyclic ring, or a nitrogen atom bonded to R ⁴ and phenylene group C Together, they may form a 5-membered heterocyclic ring or a 6-membered heterocyclic ring. )

Among them, the phenylene group C is preferably a linear or branched alkyl or alkoxy group having 1 to 4 carbon atoms, a halogen atom, or a carbon atom having 1 to 4 carbon atoms.
Those having further a substituent consisting of a fluoroalkyl group of from 4 to 4 are preferred. R ³ and R ^{4 each} have 1 carbon atom.
A linear or branched, substituted or unsubstituted alkyl or alkenyl group having 5 to 12 carbon atoms, a cycloalkyl group having 5 or 6 carbon atoms, or a linear or branched alkyl group having 1 to 8 carbon atoms, or A phenyl group having an alkoxy group, a halogen atom or a fluoroalkyl group having 1 to 4 carbon atoms as a substituent is preferable.

Among them, R ³ and R ^{4 each} represent a linear or branched unsubstituted alkyl or alkenyl group having 1 to 8 carbon atoms, or a linear or branched alkoxy group having 1 to 4 carbon atoms. More preferably, it is a linear or branched alkyl or alkenyl group having 1 to 4 carbon atoms substituted with a group, a phenyl group, a phenoxy group or an allyloxy group, or an alkyl group substituted with a heterocyclic group.

R ³ is a phenylene group C or a phenylene group C
Examples of the dye having a heterocyclic ring formed in cooperation with a nitrogen atom bonded to a compound represented by the following general formula (III) or (VI) include:

[0053]

Embedded image

(In the formula, C and R ⁴ are the same as defined in the formula (II), and R ⁵ and R ⁶ are a hydrogen atom or an alkyl group.)

[0055]

Embedded image

(However, in the general formula (VI), C and R ⁴ are the same as defined in the general formula (II), and R ⁷ and R ⁸
And R ⁹ are a hydrogen atom or an alkyl group. Among the yellow (Y) dyes having the above structure, it is particularly preferable to use the dyes having no heterocyclic ring in the molecule shown in Table 2 below in combination with the cyan dye of the present invention.

[0057]

[Table 2]

[0058]

[Table 3]

[0059]

[Table 4]

[0060]

The present invention will be described below in more detail with reference to examples. First, a description will be given with reference to the drawings. 1 to 4 are views showing a vaporized thermal transfer printer head used in the embodiment. FIG. 1 (a) is a sectional view thereof, FIG. 1 (b) is a perspective view, FIG. 2 is a plan view, and FIG. FIG. 4 is a plan view showing a state in which a cover 7 described later is removed, and FIG. 4 is a partially enlarged view of a part thereof. FIG. 5 is a schematic diagram of a serial type printer. Figure 1
As shown in FIG. 3, the printer head 1 includes an aluminum head base 2 also serving as a heat sink, a vaporizing section heated by a heater according to image information, and a recording liquid for guiding the recording liquid to the vaporizing section by a capillary action. A heater chip 3 integrally formed on a silicon substrate and a driver IC 5 covered with a potting resin 4 are mounted, and wiring is formed so as to supply current to each heater in accordance with image data to be transferred. Printed circuit board 6 and driver I
It is composed of a cover 7 which also serves as protection of C5 and a supply path of the dye.

Here, a recording liquid introduction hole 8 for introducing recording liquid into the printer head 1 is provided in the head base 2.
When the heater chip 3 is adhered to the head base 2, a groove 9 is formed as an escape area for an excess adhesive that protrudes.
The inside of the cover 7 is a recording liquid supply path 10 for supplying the recording liquid to the recording liquid introduction path of the heater chip 3. In addition, the printed circuit board 6 includes a connector terminal 11.
Is provided.

The surface of the heater chip 3 is made of N for protection.
It is covered with an i-sheet 3a, and a sheet resist 3b for forming a recording liquid introduction path is formed in a line inside the i-sheet 3a. The heater chip 3 also includes a plurality of heaters for heating and vaporizing the recording liquid, wirings for applying signal voltages based on image signals to the respective heaters, and supplying current to the heaters, and supplying the recording liquid to the heaters. Liquid introduction path for this is formed by a lithography process.

That is, as shown in FIG. 4 (a partial enlarged view of the vaporizing portion 13 at the tip of the heater chip 3 and its vicinity), for example, when the pitch Lp = 84.7 μm and the heater 14 is 2
56 are formed. At this time, one heater 14 is 1
Since the dots are transferred, a resolution of 300 DPI can be realized. Each of the heaters 14 is formed of polysilicon having a size of 20 μm × 20 μm. The heater 14 is connected to an individual electrode 15 made of aluminum and a common electrode 16 for applying and energizing a signal voltage based on an image signal. Have been. Here, the vaporizing sections 13 are separated from each other by the partition walls 17, and the recording liquid is stored in the concave portion (the recording liquid storing section 18) surrounded by the partition walls 17. On the heater 14 and around it, a fine columnar small column 19 having a diameter of 2 μm, a partition of 2 μm, and a height of 6 μm is formed of 13 × 13 via a protective film SiO ₂ (not shown). A group of books is provided as one of the constituent elements of the vaporizing unit 13.

The height of the small columnar body 19 is
8, that is, the height from the bottom surface to the top surface thereof, that is, the height of the partition wall 17 surrounding the recording liquid storage portion 18 of each heater 14, Are provided with a minute gap from each other so as to have a porous structure. Accordingly, the porous structure causes a capillary action, and thus each of the small columns 19 can hold the recording liquid in the recording liquid storage portion 18. At the same time, heater 1
When the recording liquid is heated in step 4, the surface tension of the recording liquid decreases as the temperature rises, but the recording liquid can be prevented from escaping from the vicinity of the surface of the heater 14 by the capillary action. Therefore, at the time of image transfer, a necessary recording liquid is continuously supplied.

As shown in FIG. 1A, the printer head 1 comes into contact with the recording material (printing paper) 12 at only one end 2a of the base, and has a predetermined angle with respect to the recording material 12. So it is held. Thus, the distance between the vaporizing section 13 and the recording material 12 can be kept constant. For example, the center position of the heater 14 of the vaporizing section 13 (FIG. 1)
The dashed line in (a)) is located 1.85 mm from the head base end 2 a in contact with the recording material 12, and the heater is formed on a 0.4 mm thick silicon substrate. The angle between the head base 2 and the recording material 12 such that the distance between the recording material 12 and the recording material 12 is 50 μm (however, the thickness of the adhesive layer between the silicon substrate and the head base 2 is 10 μm). At 14 °.

As described above, by appropriately changing the distance from the head base end portion 2a to the center position of the heater and the angle between the recording material 12 and the head base 2, the heater 14 and the recording material 12 Can be set to an arbitrary size. In this embodiment, a serial type printer as shown in FIG. 5 having the above-described printer heads 1Y, 1M and 1C for each color of yellow (Y), magenta (M) and cyan (C) was used. . Each printer head is connected to a head drive circuit board (not shown) via a flexible harness.

This serial type printer has a vertical (X
A paper feed roller 20 for transporting paper in the direction
A head feed shaft 21 for scanning the printer head in a direction (Y direction) orthogonal to the X direction is provided. The head feed shaft 21 is freely rotated by a motor (not shown) based on image information, and the printer head 1 is moved. It can be scanned. The paper feed in the vertical direction and the head scan in the horizontal direction are configured to be performed alternately.

Since each of the printer heads 1Y, 1M, and 1C is provided with 256 heaters 14, the serial type printer used in this embodiment is
It has the ability to print 256 lines in one scan. In addition, at the end of one scan, the platen 2 is moved by the paper feed roller 20 also serving as a head support.
The recording material (printing paper) 12 on the sheet 2 is fed by 256 lines,
Since it is possible to start printing by sequentially changing the timing for each color so that the heads 1Y, 1M, and 1C of each color start printing from a predetermined position on the printing paper 12, a color image can be printed by one scan. You can do it. FIG.
Instead of the serial type printer shown in FIG. 1, a color printer having a head configured in a line type can be used. Hereinafter, an embodiment of recording using the above-described serial type printer will be specifically described.

Example 1 No. 1 in Table 1 5% by weight of dye 4 in dibutyl phthalate
To obtain a cyan recording liquid. When this was introduced into the ink tank from the recording liquid introduction hole of the printer head shown in FIG. 1, the recording liquid spontaneously was introduced into the vaporizing portion at the tip of the recording heater chip through the passage. Next, by applying the following pulse voltage to the heater of the printer head, the recording liquid was thermally transferred to photographic paper.

(Pulse voltage condition) With 80 mW and one pulse for one gradation, ON time 12 μs and OFF time 2 μs, 256 pulses are applied per dot. When thermally transferred to plain paper under the above conditions, a clear cyan dot having an optical density of 0.8 could be formed as measured by a Macbeth reflection densitometer. When this transfer was continued, scorching occurred on the columnar portion of the printer head, making it impossible to transfer cyan. However, a large number of 5,000 or more prints could be made. The peak wavelength in the reflection spectrum of the obtained recording portion was 670 nm.

Examples 2 to 3 In place of the dyes used in Example 1, of the dyes shown in Table 1 above, Nos. And the maximum absorption wavelength (λmax) of the dye in the same manner as in Example 1.
), The measurement of the solubility in a solvent, and the transfer test of the recording liquid were carried out. As a result, as shown in Table 2, a high-solubility, clear cyan color record was obtained,
The number of prints was also good.

Examples 4 and 5 In place of the dye compound of Example 1, of the dyes shown in Table 1 above, No. 2 shown in Table 2 below. A cyan recording solution was obtained by dissolving the above dye in dibutyl phthalate at a concentration of 10% by weight, and a transfer test was performed in the same manner as in Example 1 using this recording solution. As shown in Table 2, it was possible to obtain a record of cyan with a clear color density, and the number of negative images was good.

Comparative Example In place of the dye used in Example 1, JP-A-8-2443
Using the following dye compounds A and B described in Examples of JP-A No. 66, measurement of melting point, maximum absorption wavelength, solubility, and transfer test were carried out in the same manner as in Examples. Table 3 shows the results.

[0074]

Embedded image

[0075]

[Table 5]

[0076]

The recording material of the present invention containing the dye represented by the above general formula (I) has a sufficient heat resistance to heating and hardly causes kogation due to decomposition products. . For this reason, the function of the porous structure can be maintained even during repeated recording, and can be effectively exerted. Further, since the solubility of the dye in the solvent is good, a recorded matter having high sensitivity can be obtained. According to the present invention, a large number of small-sized droplets can be formed by the porous structure, and the number of generated droplets can be freely controlled according to the heating energy corresponding to the information recorded on the recording liquid heating unit. Therefore, multi-value density gradation becomes possible, and it is possible to obtain a recording (for example, a full-color image) having image quality equal to or higher than that of a silver halide image. In addition, since it is a thermal transfer recording, the described miniaturization, maintainability, immediacy, high-quality images,
It has features such as high gradation.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view (FIG. 1A) and a lower perspective view (FIG. 1B) of a printer head used in an embodiment.

FIG. 2 is a plan view of a printer head used in the embodiment.

FIG. 3 is a plan view of a printer head used in the embodiment.

FIG. 4 is a partially enlarged view of a printer head used in the embodiment.

FIG. 5 is a schematic view of a serial type printer used in the embodiment.

FIG. 6 is a schematic front view of a main part of a printer using a conventional thermal recording head.

[Description of Signs] 1 Printer head 2 Head base 3 Heater chip 4 Potting resin 5 Driver IC 6 Printed circuit board 7 Cover 8 Recording liquid introduction hole 9 Groove 10 Recording liquid supply path 11 Connector terminal 12 Recording material (photographic paper) 13 Vaporization section 14 Heater 15 Individual electrode 16 Common electrode 17 Partition wall 18 Recording liquid storage section 19 Column

Continued on the front page (72) Inventor Yukichi Murata 1000 Kamoshita-cho, Aoba-ku, Yokohama-shi, Kanagawa Prefecture Inside Mitsubishi Research Institute Yokohama Research Laboratory (72) Inventor Kenji Shinozaki 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Inside (72) Inventor Eiki Hirano 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Corporation (72) Inventor Tatsuhiko Matsumoto 6-35, Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Corporation F term (reference) 2H086 BA03 BA04 BA14 BA26 BA52 BA56 2H111 AA12 AA27 AA35 AA47 AA48 AB00 BA03 BA41 BA47 BA55 BA76 4H056 AA01 AB03 AD26B FA03

Claims (8)

[Claims] 1. A thermal transfer recording material which is guided by a capillary phenomenon to a transfer portion having a porous structure, changes its state by heating, and is transferred to an object to be transferred facing the transfer portion. A thermal transfer recording material containing the dye represented by I). Embedded image (Wherein, rings A and B may further have a substituent,
R ¹ is an alkyl group having 4 to 12 carbon atoms which may have a substituent, R ² is a branched alkyl group having 4 to 12 carbon atoms which may have a substituent, R ¹ ≠ R ² . ) 2. The thermal transfer recording material according to claim 1, wherein R ¹ in the general formula (I) is a group selected from an i-butyl group, an n-hexyl group and an n-octyl group. 3. The compound of the formula (I) wherein R ² has 5 to 9 carbon atoms.
3. The thermal transfer recording material according to claim 1, which is an unsubstituted branched alkyl group. 4. The thermal transfer recording material according to claim 1, wherein R ² in the general formula (I) is an alkyl group branched at the β-position. 5. The thermal transfer recording material according to claim 1, wherein R ² in the general formula (I) is a 2-ethylhexyl group. 6. The transfer section has a porous structure of 0.5 to 0.3 μm.
6. A fine columnar body having a height of 1 to 15 [mu] m on one side or diameter of m, formed by arranging three or more rows and three or more columns at intervals of 0.5 to 10 [mu] m. 2. The thermal transfer recording material according to claim 1. 7. A polymer having a molecular weight of 450 or less and a melting point of 50
A solvent having a boiling point of 150 ° C. or lower and 400 ° C. or lower, being colorless and having a residual content of 0.01% by weight or less when heated to 200 ° C. in air. The thermal transfer recording material according to any one of claims 1 to 6, wherein the dye represented by the general formula (I) is dissolved in an amount of 5% by weight or more at 50 ° C or less. 8. The thermal transfer recording material according to claim 7, wherein the solvent is at least one selected from aromatic carboxylic esters, aliphatic carboxylic esters, glycol ethers, glycol esters and aromatic hydrocarbons.