JP3075481B2 - Ink sheet for thermal transfer recording - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an ink sheet for thermal transfer recording, and more particularly, to an ink sheet for thermal storage recording, which has improved storage stability, is fused to an image receiving sheet for thermal transfer recording, and is soiled on the sheet. To prevent the occurrence of
The present invention relates to a thermal transfer recording ink sheet capable of suppressing a decrease in image density.

[Prior Art and Problems to be Solved by the Invention] Conventionally, as a method for obtaining a color hard copy, a color recording technique using ink jet, electrophotography, thermal transfer, or the like has been studied.

Among them, the thermal transfer method has advantages such as easy operation and maintenance, downsizing of the apparatus and cost reduction.

 The following two types of thermal transfer systems are available.

That is, a transfer sheet having a fusible ink layer on a support is heated imagewise (imagewise) by a laser or a thermal head, and the fusible ink layer is melt-transferred onto an image receiving sheet for thermal transfer recording. Using a thermal transfer recording ink sheet having an ink layer containing a thermal diffusible dye (sublimable dye) on a support, and thermally diffusing the thermal diffusible dye to an image receiving sheet for thermal transfer recording. And two types.

Of these, the thermal diffusion transfer method can control the gradation of the image by changing the amount of dye transfer according to the change in the thermal energy of the thermal head. In recent years, attention has been paid to a method of obtaining a color image having a continuous change in color shading by performing the method.

However, the first problem with this thermal diffusion transfer method is that the storage stability of the thermal transfer recording ink sheet used is not good. When stored, the heat-diffusible dye is released from the binder over time and is accumulated on the surface of the heat-sensitive layer,
Moreover, since it moves to the back of the sheet where it is in contact,
At the time of recording, the entirety of the thermal head and the sheet to be transferred (hereinafter, referred to as an image receiving sheet for thermal transfer recording) may be contaminated with a dye (ground contamination).

The second problem is that it is difficult to suppress a decrease in image density in the thermal transfer recording ink sheet in which the heat diffusible dye is released from the binder as described above.

The third problem is that, during thermal transfer, the entire ink layer from the thermal transfer recording ink sheet is fused to the thermal transfer recording image receiving sheet side.

The present invention has been made to solve the above various problems.

That is, an object of the present invention is to provide a thermal transfer recording method which can improve the storability, prevent fusion with an image receiving sheet for thermal transfer recording and prevent the sheet from being stained, and can also suppress a decrease in image density. To provide an ink sheet for printing.

[Means for Solving the Problems] The present invention for achieving the above object is selected from the group consisting of a heat diffusible dye, a binder resin, a polyester-modified silicone resin, a urethane-modified silicone resin, and an acryl-modified silicone resin. An ink sheet for thermal transfer recording, wherein an ink layer containing at least one modified silicone resin is laminated on a support.

 Hereinafter, the present invention will be described in detail.

(I) Thermal Transfer Recording Ink Sheet The thermal transfer recording ink sheet of the present invention basically has a structure in which an ink layer 2 is laminated on a support 1 as exemplified in FIG. The layer 2 is not limited to a single layer and may be composed of a plurality of layers.

-Ink- The ink layer in the present invention basically contains a heat diffusible dye, a binder resin, and a modified silicone resin.

Heat-diffusing dye The heat-diffusing dye used in the present invention is not particularly limited as long as it is heat-diffusing or sublimable.

Thermal diffusible dyes include cyan dye, magenta dye,
Yellow dyes can be mentioned.

Examples of the cyan dye include JP-A-59-78896 and JP-A-59-78896.
-227948, 60-24966, 60-53563, 60-13
No. 0735, No. 60-131292, No. 60-239289, No. 61-1939
No. 6, No. 61-22993, No. 61-31292, No. 61-31467,
No. 61-35994, No. 61-49893, No. 61-148269, No. 62
-191191, 63-91288, 63-91287, 63-29
Examples include naphthoquinone-based dyes, anthraquinone-based dyes, and azomethine-based dyes described in each publication such as No. 0793.

Examples of the magenta dye include JP-A-59-78896, JP-A-60-30392, JP-A-60-30394, and JP-A-60-2535.
No. 95, JP-A-61-262190, JP-A-63-5992, JP-A
Examples include anthraquinone dyes, azo dyes, and azomethine dyes described in JP-A-63-205288, JP-A-64-159, JP-A-64-63194, and the like.

As yellow dyes, JP-A-59-78896, JP-A-6-78896
0-27594, JP-A-60-31560, JP-A-60-53565,
Examples thereof include methine dyes, azo dyes, quinophthalone dyes and anthrisothiazole dyes described in JP-A Nos. 61-12394 and 63-122594.

Further, as the heat diffusible dye, an azomethine dye obtained by coupling a compound having a closed or open chain active methylene group with an oxidized form of a p-phenylenediamine derivative or an oxidized form of a p-aminophenol derivative; And phenol or naphthol derivatives or p
An indoaniline dye obtained by a coupling reaction with an oxidized form of a phenylenediamine derivative or an oxidized form of a p-aminophenol derivative can also be suitably used.

The thermal diffusible dye may be any of a yellow dye, a magenta dye, and a cyan dye as long as the image to be formed is a single color.

Further, depending on the color tone of the image to be formed, two or more of the three types of heat diffusible dyes or other colors may be included.

The amount of the heat-diffusible dye used in the present invention depends on the support.
It is usually 0.1 to 20 g, preferably 0.2 to 5 g per 1 m ² .

Binder Resin In the present invention, a resin known in the field of thermal transfer recording can be used as a binder resin used for the ink layer, but preferred are acetal resins and / or cellulose resins described below. is there.

First, as the acetal-based resin, there are various compounds depending on the degree of acetalization and the content of acetyl groups and the like. Representative examples include polyvinyl acetoacetal and polyvinyl butyral.

Among the acetal resins, preferred for the purpose of the present invention are those having a polymerization degree of 300 or more, desirably 1500 to 2400, a glass transition point (Tg) of 50 to 200 ° C., an acetalization degree of 60 mol% or more, and acetyl. It is an acetal resin having a group of 10 mol% or less.

The commercial names of the acetal resins satisfying such conditions include KS-1, KS-5, KS-8, BL-1, BL-2,
BL-3, BL-S, BM-1, BM-2, BM-5, BM-S, BH
-3, BX-1 [all manufactured by Sekisui Chemical Co., Ltd.].

Examples of the cellulose resin include nitrocellulose, ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, cellulose acetate, and cellulose acetate butyrate.

Among these cellulose resins, nitrocellulose is particularly preferred.

Furthermore, among the nitrocellulose, preferred for the purpose of the present invention are, based on the test method of JIS K-6703, a nitrogen content of 10.7-12.2%, a polymerization degree of 35-110, and a viscosity of 1.0-6.2 seconds, respectively. (Measured at 25.0% solids), 3 to
8 seconds (measured at 20.0% solids), 1.5-500 seconds (solids 12.2%)
%), 1.1-5.2 seconds (measured at 30% solids), 100-1
Nitrocellulose having a value of 40 cps (measured by dissolving 1.5 g of dry nitrocellulose in 100 cc of butyl acetate).

Nitro-cellulose brands that meet these conditions are listed as HIG1 / 16, HIG1 / 8, HIG1 / 4, HIG1 / 2, HIG1, H
IG2, HIG7, HIG20, HIG60, HIG120, HIG500, LIG1 / 8, L
IG1 / 4, LIG1 / 2, SL-1, HI1000, HI2000, clear H1 /
4, chip H1 / 2, etc. [all manufactured by Asahi Kasei Kogyo Co., Ltd.].

In the present invention, as the binder resin, in addition to the acetal-based resin and the cellulose-based resin, resins conventionally known in the field of thermal transfer recording can be used.

For example, examples of the known resin include acrylic resin, methacrylic resin, polycarbonate, polyvinyl alcohol, polyvinyl formal, polyvinyl ether, polyvinyl pyrrolidone, polystyrene, polystyrene copolymer, and ionomer resin.

In the present invention, one or more of the various binder resins described above can be used.

These binder resins are usually blended in an amount of 0 to 50% by weight based on the total amount of the resins in the ink layer.

Further, the weight ratio of the binder resin and the heat-diffusing dye in the ink layer in the present invention is preferably in the range of 1:10 to 10: 1.

Modified Silicone Resin In the present invention, it is important that the ink layer contains at least one modified silicone resin selected from the group consisting of a polyester-modified silicone resin, a urethane-modified silicone resin, and an acryl-modified silicone resin.

When the ink layer contains the specific modified silicone resin, the thermal transfer recording ink sheet improves the releasability from the thermal transfer recording image receiving sheet, and as a result, mutual fusion is prevented.

In addition, since the specific modified silicone resin has good compatibility with the binder resin, unlike silicone oil and straight silicone, the storage stability of the thermal transfer recording ink sheet is improved, and the image density (transfer density) Is not reduced.

As the specific modified silicone resin, room temperature (20
C), and a wax-like modified silicone resin having a melting point of 35 to 100C is particularly preferable.

Among the modified silicone resins described above, polyester-modified silicone resins are preferred for the purpose of the present invention,
Further, a polyester-modified silicone resin having a molecular weight of 500 to 20,000 is preferred.

The polyester portion of the polyester-modified silicone resin can be formed by copolymerization of a dicarboxylic acid and a diol or ring-opening polymerization of a lactone ring.

The dimethylpolysiloxane-bonded portion and the polyester portion in the polyester-modified silicone resin may be, for example, a polyester having a main chain to which a dimethylpolysiloxane portion is grafted, and a polyester portion in a block shape on both sides or one side of the dimethylpolysiloxane. They may be combined.

Further, the specific modified silicone resin used in the present invention may have a reactive group such as a hydroxyl group or a carboxyl group at a terminal, and in that case, it can be crosslinked with a crosslinking agent such as a diisocyanate.

In the present invention, the amount of the specific modified silicone resin in the ink layer is usually 0.01 to 10% by weight, preferably 0.05 to 5% by weight. 0.01% by weight
If it is less than 10%, the effect of the present invention cannot be sufficiently exhibited, and if it exceeds 10% by weight, it is not preferable because soiling may occur or storage stability may be deteriorated.

Additives In the present invention, various additives can be added to the ink layer as needed.

Examples of the additives include fluororesins, surfactants, release compounds such as waxes, fillers such as metal fine powder, silica gel, carbon black, and resin fine powder, and curing agents capable of reacting with binder components (for example, isocyanates and Radiation-active compounds such as acrylics and epoxies).

Further, in order to promote the transfer, for example, JP-A-59-10
Hot-melt substances such as waxes and higher fatty acid esters described in No. 6997 can be used.

The amount of the additive to be added is not uniformly determined depending on the type and purpose of the additive, but the total amount of the additive is usually 20% by weight or less based on the binder resin.

Formation of Ink Layer The ink layer was prepared by dispersing or dissolving the heat diffusible dye, the binder resin and the modified silicone resin, and optional components added as necessary in a solvent to prepare an ink layer forming coating liquid. It can be formed by applying the coating liquid on a support and drying.

The binder resin may be used not only by dissolving one kind or two or more kinds in a solvent, but also dispersed in a latex form.

Examples of the solvent include water, alcohols (eg, ethanol, propanol), cellosolves (eg, methyl cellosolve, ethyl cellosolve, etc.), aromatics (eg, toluene, xylene, chlorobenzene, etc.), ketones (eg, acetone, methyl ethyl ketone, etc.). ), Ethers (eg, tetrahydrofuran, dioxane, etc.),
Chlorine solvents (eg, chloroform, trichloroethylene, etc.) can be mentioned.

These solvents may be used alone or in combination of two or more.

The above-mentioned coating can be performed by a known gravure roll, such as face-to-face coating, extrusion coating, wire bar coating, and roll coating.

The ink layer is 0.2 to 10 μm on the support, and 0.3 to 10 μm.
It is desirable to form it with a thickness of 3 μm.

Further, the ink layer, a yellow ink layer containing a binder resin and a yellow dye, a magenta ink layer containing a binder resin and a magenta dye, and a cyan ink layer containing a binder resin and a cyan dye, are fixed along the surface direction. It is preferable that the support is repeatedly formed on the support.

Further, in addition to the three ink layers arranged along the surface direction, a black ink layer containing a black image forming substance may be interposed between any two adjacent layers in the surface direction.

In particular, for the black ink layer, a diffusion transfer type ink may be used, but a clear character can be obtained even with a melt transfer type ink.

-Support-As the support used in the present invention, any material can be used as long as it has good dimensional stability and can withstand the heat of a heat source such as a thermal head at the time of image recording.
Thin paper such as glassine paper, heat-resistant plastic films such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyamide, polycarbonate, polysulfone, polystyrene, and polyimide can be used.

 The thickness of the support is usually preferably in the range of 2 to 10 μm.

-Other layers- An undercoat layer can be provided between the ink layer and the support in order to enhance the adhesiveness and the like.

Further, a fusion preventing layer can be provided on the ink layer.

The thickness is usually 0.01-5 μm, preferably 0.05-1 μm
m.

If the thickness is less than 0.01 μm, the effect of preventing fusion is not sufficiently exhibited, and if it exceeds 5 μm, the diffusion of the heat diffusing dye from the ink layer to the image receiving layer is inhibited, and a sufficient image density is obtained. It is not preferable because it becomes difficult.

The anti-fusion layer can usually be formed of, for example, solid waxes such as polyethylene wax, amide wax, Teflon powder, fluorine, phosphate-based surfactant silicone oil, silicone resin, fluorine resin and the like.

A sticking prevention layer may be provided on the back surface of the support (on the side opposite to the ink layer) for the purpose of preventing the head from sticking, sticking, and wrinkling to the support.

The thickness of the anti-sticking layer is preferably in the range of 0.1 to 1 μm.

Further, by forming perforations on the thermal transfer recording ink sheet or providing detection marks for detecting the positions of areas having different hues, convenience in use can be achieved.

(II) Thermal Transfer Recording Image-Receiving Sheet The thermal transfer recording image-receiving sheet can usually be composed of a substrate and an image receiving layer formed thereon.

In some cases, the image-receiving sheet for thermal transfer recording can be formed with a self-supporting image-receiving layer.

In the heat-sensitive transfer recording image-receiving sheet comprising the self-supporting image-receiving layer, the base material is not particularly used, so that the number of parts can be reduced.

-Image Receiving Layer- This image receiving layer can be usually formed with a binder for an image receiving layer and various additives.

In some cases, the image receiving layer can be formed using only the binder for the image receiving layer.

Image receiving layer binder As the image receiving layer binder, for example, polyvinyl chloride resin, a copolymer resin of vinyl chloride and other monomers,
(For example, vinyl chloride-vinyl acetate copolymer resin, ethylene-vinyl chloride copolymer), polyester resin, acrylate ester, chlorinated polyethylene, ethylene-vinyl acetate copolymer, ketone resin, alkyd resin, polyvinylpyrrolidone, polycarbonate, Examples thereof include cellulose triacetate, styrene acrylate resin, vinyl toluene acrylate resin, polyurethane resin, polyamide resin, urea resin, polycaprolactone resin, styrene-maleic anhydride resin, and polyacrylonitrile resin. Among them, vinyl chloride-vinyl acetate copolymer resin, polyester resin, polyvinyl chloride resin and the like are preferable.

These can be used alone or in combination of two or more.

The above various resins may be newly synthesized and used,
Commercial products can also be used. For example, commercially available polyester resins include Byron 200, Byron 290, Byron 600, etc. [all manufactured by Toyobo Co., Ltd.], KA-1038C (Arakawa Chemical), TP220, TP235 [all manufactured by Nihon Gosei Co., Ltd.]
Manufactured) can be used.

The vinyl chloride-vinyl acetate copolymer resin has a vinyl chloride component content of 50 to 100% by weight and a degree of polymerization of 50 to 250.
About 0 is preferable.

The vinyl chloride-vinyl acetate copolymer resin preferably used in the present invention does not necessarily need to be composed only of a vinyl chloride component and a vinyl acetate component, and a vinyl alcohol component and a maleic acid as long as the object of the present invention is not impaired. It may contain components and the like. Such vinyl chloride-vinyl acetate copolymers include, for example, Eslek A,
Esrec C, Esrec M [Sekisui Chemical Co., Ltd.], Vinylite VACH, Vinylite VYHH, Vinylite VMCH, Vinylite VYHD, Vinylite VYLF, Vinylite VYNS, Vinylite VMCC, Vinylite VMCA, Vinylite
VACD, Vinylite VERR, Vinylite VROH (all manufactured by Union Carbide), Denka Vinyl 1000GKT, Denka Vinyl 1000L, Denka Vinyl 1000CK, Denka Vinyl 1000A,
DENKAVINYL 1000LK _2, DENKAVINYL 1000AS, DENKAVINYL 1000MT _2, DENKAVINYL 1000CSK, DENKAVINYL 1000
CS, DENKAVINYL 1000GK, DENKAVINYL 1000GSK, DENKAVINYL 1000GS, DENKAVINYL 1000LT _3, DENKAVINYL 1
000D, Denka Vinyl 1000W [or more, Denki Kagaku Kogyo Co., Ltd.]
Manufactured].

In any case, from the viewpoint of physical properties, the binder for the image receiving layer is preferably a resin having a glass transition point (Tg) in the range of −20 to 150 ° C., particularly preferably a resin in the range of 30 to 120 ° C. In terms of molecular weight, Mw is 2000 to 100.00
Resins in the range of 0 are preferred.

In forming the image receiving layer, the above various resins are crosslinked by radiation, heat, moisture, a catalyst, or the like by utilizing their reactive active points (if there is no reactive active point, it is applied to the resin). Alternatively, it may be cured.

In that case, a radiation-active monomer such as epoxy or acrylic, or a crosslinking agent such as isocyanate can be used.

Additives A release agent, an antioxidant, a UV absorber, a light stabilizer, a filler (inorganic fine particles, organic resin particles), and a pigment may be added to the image receiving layer. Further, a plasticizer, a thermal solvent or the like may be added as a sensitizer. These are appropriately used in consideration of compatibility with the binder, storage stability of the image, and the like.

The release agent can improve the releasability between the thermal transfer recording ink sheet and the thermal transfer recording image receiving sheet.

Examples of such release agents include solid waxes such as silicone oil, polyethylene wax, amide wax, and Teflon powder; fluorine-based and phosphate-based surfactants; and among them, silicone oil is preferred.

This silicone oil is classified into a type that is simply added (simple addition type) and a type that is cured or reacted (curing reaction type).

In the case of the simple addition type, it is preferable to use a modified silicone oil as the silicone oil in order to improve the compatibility with the binder.

Examples of the modified silicone oil include polyester-modified silicone resin (or silicon-modified polyester resin), acryl-modified silicone resin (or silicon-modified acrylic resin), urethane-modified silicone resin (or silicon-modified urethane resin), and cellulose-modified silicone resin ( Alternatively, a silicon-modified cellulose resin), an alkyd-modified silicone resin (or a silicon-modified alkyd resin), an epoxy-modified silicone resin (or a silicon-modified epoxy resin), and the like can be given.

That is, a polyester-modified silicone resin containing a polysiloxane resin in the main chain and copolymerizing polyester in a block shape, a silicon-modified polyester resin having a dimethylpolysiloxane portion as a side chain bonded to the polyester main chain, and dimethylpolysiloxane. Block copolymers, alternating copolymers, graft copolymers, random copolymers, etc. of siloxane and polyester moieties can also be used as modified silicone oils or resins.

In particular, in the present invention, it is preferable to add a polyester-modified silicone resin.

Typical polyester-modified silicone resins include, for example, block copolymers of dimethylpolysiloxane with polyesters, which are copolymers of diols and dibasic acids or ring-opening polymers of caprolactone (both terminals or fragments of dimethylpolysiloxane). Including copolymers whose ends are blocked with the above polyester portion, or conversely, where the above polyester is blocked with dimethylpolysiloxane.) Or (dimethyl) polysiloxane bonded to the side chain with the above polyester as the main chain Examples of the copolymer include:

The amount of these simple addition type silicone oils is
Although it cannot be determined uniformly because it may vary variously depending on the type, generally speaking, it is usually 0.5 to 50% by weight, preferably 1 to 20% by weight, based on the binder for the image receiving layer. % By weight.

Examples of the curing reaction type silicone oil include reaction curing type, light curing type, and catalyst curing type.

As the reaction-curable silicone oil, there is one obtained by reacting and curing an amino-modified silicone oil and an epoxy-modified silicone oil.

KS-705F-PS, KS-705F-PS-1, KS-770-P as catalyst-curable or photocurable silicone oils.
L-3 [all are catalyst-curable silicone oils: manufactured by Shin-Etsu Chemical Co., Ltd.], KS-720, KS-774-PL-3 are all photo-curable silicone oils: manufactured by Shin-Etsu Chemical Co., Ltd. No.

The addition amount of these curable silicone oils is preferably 0.5 to 30% by weight of the binder for the image receiving layer.

The release agent layer may be provided on a part of the surface of the image receiving layer by dissolving or dispersing the above-mentioned release agent in a suitable solvent and applying the resultant, followed by drying.

Next, examples of the antioxidant include JP-A-59-182785 and JP-A-59-182785.
60-130735, antioxidants described in JP-A-1-127387 and the like,
And known compounds for improving image durability in photographic and other image recording materials.

As the UV absorber and light stabilizer, JP-A-59-15
8287, 63-74686, 63-145089, 59-196292, 6
2-229594, 63-122596, 61-283595, JP-A-1-204
Examples of the compounds include compounds described in 788 and known compounds for improving image durability in photographs and other image recording materials.

Examples of the filler include inorganic fine particles and organic resin particles.

Examples of the inorganic fine particles include silica gel, calcium carbonate, titanium oxide, acid clay, activated clay, and alumina.
Resin particles such as guanamine resin particles, acrylic resin particles, and silicon resin particles can be used. These inorganic and organic resin particles vary depending on the specific gravity.
Is preferred.

Representative examples of the pigment include titanium white, calcium carbonate, zinc oxide, barium sulfate, silica, talc, clay, kaolin, activated clay, and acid clay.

Examples of the plasticizer and the thermal solvent include phthalic esters (for example, dimethyl phthalate, dibutyl phthalate, dioctyl phthalate, didecyl phthalate, etc.) and adipic esters (dioctyl adipate, methyl lauryl adipate, di-adipate). 2-ethylhexyl, ethyl lauryl adipate, etc.), other oleates, succinates, maleates, sebacates, citrates, epoxystearate epoxies, and triphenyl phosphate And glycol esters such as ethyl phthalyl ethyl glycolate and butyl phthalyl butyl glycolate.

In the present invention, the amount of the additive as a whole is usually in the range of 0.1 to 50% by weight based on the binder for the image receiving layer.

Formation of the image receiving layer The image receiving layer is prepared by dispersing or dissolving the components for forming the image receiving layer in a solvent to prepare a coating solution for the image receiving layer, and applying the coating solution for the image receiving layer to the surface of the substrate, It can be formed by a coating method of drying, a lamination method of melt-extruding a mixture having a component for forming the image receiving layer, and laminating the mixture on the surface of a substrate.

Examples of the solvent used in the above coating method include methyl ethyl ketone, toluene, diquioxane, anone, methyl isobutyl ketone, alcohol, ethyl acetate, butyl acetate, chloroform and the like. When the above-described laminating method is employed, when the base material is a synthetic resin as described later, a co-extrusion method may be employed. The image receiving layer is
It may be formed over the entire surface of the substrate, or may be formed on a part of the surface.

The thickness of the image receiving layer is generally 3 to 50 μm, preferably 3 to 50 μm.
It is about 15 μm.

On the other hand, when the image receiving layer itself forms a thermal transfer recording image receiving sheet because the image receiving layer is self-supporting, the thickness of the image receiving layer is usually 60 to 200 μm, preferably 90 to 150 μm.
It is about.

-Substrate-Examples of the substrate include paper, coated paper, synthetic paper (polypropylene, polystyrene or a composite material obtained by laminating them with paper), white polyethylene terephthalate base film, transparent polyethylene terephthalate base film, polyolefin coating. Paper can be mentioned.

The thickness of the substrate is usually 30 to 300 μm, preferably 80 to 200
μm.

-Other layers- An overcoat layer may be laminated on the surface of the image receiving sheet for thermal transfer recording for the purpose of preventing fusion and improving image storability. This layer can be formed by a usual coating method or a laminating method. The thickness of this layer is usually from 0.05 to 5 μm. In addition, a cushion layer can be provided between the base material and the image receiving layer of the image transfer sheet for thermal transfer recording in order to reduce noise and transfer and record an image corresponding to image information with good reproducibility.

Examples of the material constituting the cushion layer include urethane resin, acrylic resin, ethylene-based resin, butadiene rubber, and epoxy resin.

 The thickness of the cushion layer is preferably 5 to 25 μm.

(III) Formation of Image To form an image, the ink layer surface of the ink sheet for thermal transfer recording of the present invention and the image receiving layer surface of the image receiving sheet for thermal transfer recording are overlapped so as to be in contact with each other. Apply heat energy imagewise.

Then, the thermal diffusible dye in the thermal transfer recording ink sheet vaporizes or sublimates by an amount corresponding to the applied thermal energy, moves to the thermal transfer recording image receiving sheet side, and is fixed to the image receiving layer and there. Form an image.

A thermal head is generally used as a heat source for applying the heat energy. In addition, a known heat source such as a laser beam, an infrared flash, and a hot pen can be used.

The thermal energy may be applied from the thermal transfer recording image receiving sheet, from the thermal transfer recording ink sheet side, or from both.

However, from the viewpoint of effective use of heat energy,
It is preferred that the heat transfer recording be performed from the ink sheet side.

It is also used for controlling the thermal energy to express the shades of the image, or for promoting the diffusion of the dye to the image-receiving sheet for thermal transfer recording to more reliably express the continuous tone of the image. It is more preferable to apply thermal energy from the side of the thermal transfer recording image receiving sheet.

Further, from the viewpoint that the advantages of the above two methods can be enjoyed at the same time, it is preferable to carry out from the side of the ink sheet for thermal transfer recording and the side of the image receiving sheet for thermal transfer recording.

When a thermal head is used as a heat source for applying thermal energy, the applied thermal energy can be changed continuously or in multiple steps by modulating the voltage or pulse width applied to the thermal head.

When laser light is used as a heat source for providing heat energy, the applied heat energy can be changed by changing the amount of laser light or the irradiation area.

By using a dot generator with a built-in acousto-optic element, it is possible to apply heat energy according to the size of a halftone dot.

When a laser beam is used as a heat source, it is desirable that the thermal transfer recording ink sheet and the thermal transfer recording image receiving sheet be sufficiently adhered to each other, and the surface irradiated with the laser beam is to improve the absorption of the laser beam. For example, it may be colored black.

When an infrared flash lamp is used as a heat source for applying heat energy, irradiation of the lamp is preferably performed through a colored layer such as black as in the case of using laser light.

Irradiation of this lamp can be performed through a pattern or a halftone pattern that continuously expresses the shading of an image such as black, or a colored layer such as black and a negative corresponding to the negative of the pattern. It can also be performed in combination with a pattern.

When the thermal energy is applied in this manner, a dye in an amount corresponding to the energy amount is thermally transferred from the thermal transfer recording ink sheet to the image receiving layer of the thermal transfer recording image receiving sheet, and a one-color image is recorded thereon. However, when the ink sheet for thermal transfer recording is replaced, a color image of a color photograph can be obtained.

For example, if the thermal transfer recording ink sheets of yellow, magenta, cyan and, if necessary, black are exchanged sequentially, and thermal transfer is performed in accordance with each color, a color photographic color image composed of a combination of each color can be obtained.

Instead of using the thermal transfer recording ink sheet of each color as described above, the following method can be used.

That is, a thermal transfer recording ink sheet having areas formed separately in each color in advance is prepared, first, a yellow color separation image is thermally transferred using a yellow area, and then a magenta color separation image is formed using a magenta area. The color image is thermally transferred, and thereafter, this operation is sequentially repeated to thermally transfer the yellow, magenta, cyan, and, if necessary, black and color separated images.

This method has an advantage that it is not necessary to replace the thermal transfer recording ink sheet.

[Examples] Next, the present invention will be described more specifically based on examples.

 In the following, “parts” means “parts by weight”.

Example 1 A coating liquid for forming an ink layer having the following composition was applied to a corona-treated surface of a polyethylene terephthalate film having a thickness of 9 μm as a support by a wire bar coating method so that the thickness after drying became 1 μm. After drying, apply one or two drops of silicone oil (X-41, 4003A, manufactured by Shin-Etsu Silicone Co., Ltd.) on the back surface that has not been corona-treated and spread it over the entire surface. I got a sheet.

Coating solution for forming ink layer Disperse dye [Kayaset Zaru 13 manufactured by Nippon Kayaku Co., Ltd.]
6] ······ 4 parts polyvinyl butyral [degree of polymerization 1700, Tg 85.5 ° C, degree of acetalization 64 mol%, acetyl group 3 mol% or less, trade name BX-1: manufactured by Sekisui Chemical Co., Ltd. ] 5 parts Polyester modified silicone [Shin-Etsu Chemical Co., Ltd.]
Manufactured by: trade name X-24-8310] 0.4 parts Toluene 40 parts Methyl ethyl ketone 40 parts Dioxane ········· 10 parts Next, synthetic paper with a thickness of 150 μm [trade name Yupo F
PG-150; manufactured by Oji Yuka Synthetic Paper Co., Ltd.], a coating solution for forming an image receiving layer having the following composition is applied by a wire-bar coating method, and further temporarily dried with a drier, and then heated to 100 ° C.
Dry for 1 hour in an oven of 5μm thick on synthetic paper
Was obtained.

Coating liquid for forming image receiving layer Vinyl chloride-vinyl acetate copolymer (trade name: VYHH: manufactured by Union Carbide Co., Ltd.) 10 parts Methyl ethyl ketone 90 parts Next, the thermal transfer After storing the recording ink sheet at 60 ° C. for 8 days, the sheet and the thermal transfer recording image receiving sheet are overlapped so that the former ink layer surface and the latter image receiving layer surface are in contact with each other. 0.35W / dot output using a thermal head from the support side of
By heating under the condition of dot density 8 dots / mm,
Image recording was performed.

After image recording, background stain on an unprinted portion (white background) of the image receiving layer surface of the thermal transfer recording image receiving sheet, transfer density of the image receiving layer surface, fusion of the thermal transfer recording ink sheet and the thermal transfer recording image receiving sheet. The condition was evaluated according to the following criteria.

 The results are shown in Table 1.

Background stain: ○: There was no staining by the dye in the unprinted area on the surface of the image receiving layer.

 X: The unprinted portion was contaminated with dye.

Transfer density: The reflection density OD value was measured with an optical densitometer.

 ◎ ・ ・ ・ ・ ・ ・ OD value is 2.3 or more.

 ○ ・ ・ ・ ・ OD value is 2.0 or more.

 X: OD value is 2.0 or less.

Fusion: ○: Only the paint was transferred to the image receiving layer, and the heat-sensitive layer was peeled off from the support.

 X: The entire ink layer was transferred to the image receiving layer.

(Example 2) In Example 1, the composition of the ink layer forming coating liquid was set to the following composition, the image receiving layer forming coating liquid was set to the following composition, and the thickness of the image receiving layer after drying was changed. Except having set it as 10 micrometers, it implemented similarly to Example 1.

 The results are shown in Table 1.

Coating liquid for forming ink layer Dispersion paint [Kayat Blue 136 manufactured by Nippon Kayaku Co., Ltd.] 4 parts Nitrocellulose [Viscosity 1/2 second, nitrogen content 11.5-12.2]
%, Degree of polymerization 80-95, trade name HIG 1/2: manufactured by Asahi Kasei Kogyo Co., Ltd.] 3.5 parts polyvinyl acetoacetal [trade name KS-5: Sekisui Chemical Co., Ltd. 5) Polyester modified silicone [trade name: X-24-8301:
Shin-Etsu Chemical Co., Ltd.] 0.4 parts Toluene 40 parts Methyl ethyl ketone 40 parts Dioxane ... 10 parts Coating solution for forming image receiving layer Polyester resin [trade name: Byron 200: manufactured by Toyobo Co., Ltd.] 10 parts Methyl ethyl ketone 90 Example 3 Example 3 was carried out in the same manner as in Example 1 except that the compositions of the coating liquid for forming an ink layer and the coating liquid for forming an image receiving layer in Example 1 were changed to the following compositions.

 The results are shown in Table 1.

Coating solution for ink layer Dispersion paint [Kayaset Blue 136, manufactured by Nippon Kayaku Co., Ltd.] 4 parts Nitrocellulose [trade name: HIG 1/16: manufactured by Asahi Kasei Corporation]・ 5 parts polyvinyl butyral [degree of polymerization 1700. Trade name BX-1,
Sekisui Chemical Co., Ltd.] 3.5 parts Polyester modified silicon [trade name X-24-8310: Shin-Etsu Chemical Co., Ltd.] 0.4 parts Methyl ethyl ketone 100 parts Coating solution for forming image receiving layer Vinyl chloride resin (degree of polymerization 600) 10 parts Methyl ethyl ketone 100 parts Cyclohexanone ... 50 parts (Example 4) In Example 1, a polyester-modified silicone which is one of the components of the coating liquid for forming an ink layer was replaced with a urethane-modified silicone [trade name: Diaromer SP-2105: Dainichi Seika Co., Ltd.
Ex.] Was carried out in the same manner as in Example 1. The results are shown in Table 1.

(Example 5) In Example 2, a polyester-modified silicone, which is one of the components of the coating liquid for forming an ink layer, was replaced with an acrylic-modified silicone [trade name: Cymac US-270: Toa Gosei Chemical Co., Ltd.]
Ex.] Was carried out in the same manner as in Example 1.

 The results are shown in Table 1.

(Example 6) In Example 2, the polyester-modified silicone which is one of the components of the coating liquid for forming an ink layer was replaced with a urethane-modified silicone resin (trade name: Diaromer SP-712: manufactured by Dainichi Seika Co., Ltd.). Except for this, the procedure was the same as in Example 1.

 The results are shown in Table 1.

(Comparative Example 1) The procedure was performed in the same manner as in Example 1 except that the polyester-modified silicone which was one of the components of the coating liquid for forming an ink layer was not used. The results are shown in Table 1.

(Comparative Example 2) The procedure was performed in the same manner as in Example 2 except that the use of the polyester-modified silicone, one of the components of the coating liquid for forming an ink layer, was omitted.

 The results are shown in Table 1.

(Comparative Example 3) The procedure of Example 1 was repeated, except that dimethylpolysiloxane was used instead of the polyester-modified silicone, which is one of the components of the coating liquid for forming an ink layer.

 The results are shown in Table 1.

[Effect of the Invention] The ink sheet for thermal transfer recording of the present invention has improved storage stability, prevents fusion with the image receiving sheet for thermal transfer recording, prevents generation of background stain on the sheet, and reduces image density. Reduction can be suppressed.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of an ink sheet for thermal transfer recording of the present invention. 1 ... support, 2 ... ink layer.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-126590 (JP, A) JP-A-4-4189 (JP, A) JP-A 4-112085 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) B41M 5/38-5/40

Claims (1)

(57) [Claims] An ink layer containing a heat-diffusible dye, a binder resin, at least one modified silicone resin selected from the group consisting of a polyester-modified silicone resin, a urethane-modified silicone resin and an acryl-modified silicone resin is provided on a support. An ink sheet for thermal transfer recording, characterized by being laminated on a sheet.