JPH04310795A - Image-receiving sheet for thermal transfer recording - Google Patents

Abstract

PURPOSE:To provide an image receiving sheet for thermal transfer recording wherein both transfer defect and curl in forming an image are prevented. CONSTITUTION:In an image-receiving sheet for thermal transfer recording composed of an image-receiving layer and a base material, the base material is a laminated material having a polyethylene resin mixture layer containing high density polyethylene and low density polyethylene on both surfaces of paper. The weight ratio of the high density polyethylene to the low density polyethylene in the polyethylene resin mixture layer on a front surface side of said paper is 0.5 or over. The weight ratio of the high density polyethylene to the lower density polyethylene in the polyethylene resin mixture layer on the rear surface side of the paper is 1.0 or over.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to an image-receiving sheet for thermal transfer recording, and more specifically, the present invention relates to a thermal transfer recording sheet that prevents deterioration of image quality due to transfer omissions during image formation and prevents curling (warping or bending). The present invention relates to an image receiving sheet.

0002

[Prior Art and Problems to be Solved by the Invention] In recent years, inkjet,
Color recording technologies using electrophotography, thermal transfer, etc. are being considered.

Among these, the thermal transfer method in particular has many advantages, such as ease of operation and maintenance, the ability to make the device compact, and the ability to reduce costs.

In this thermal transfer method, a transfer sheet having a meltable ink layer on a support is imagewise heated by a laser or a thermal head to melt and transfer the meltable ink layer onto a transfer sheet. Thermal diffusion transfer method (sublimation) uses a transfer sheet having an ink layer containing a heat-diffusible dye (for example, a sublimable dye) on a support to diffusely transfer only the heat-diffusible dye to the transfer sheet. There are two types: transfer method).

The latter thermal diffusion transfer method has recently been developed as a method that can control the gradation of an image by changing the amount of heat-diffusible dye transferred in response to changes in the thermal energy of the thermal head. Attention has been paid.

On the other hand, as a typical image-receiving sheet for thermal transfer recording used in the above-mentioned thermal transfer recording system, there can be mentioned a laminated sheet having an image-receiving layer containing a thermoplastic resin and a release agent on the surface of a support.

In this image-receiving sheet for thermal transfer recording, a heat-diffusible dye is transferred to the image-receiving layer.

The support for this image-receiving sheet for thermal transfer recording may be, for example, paper, coated paper, synthetic paper (polypropylene, polystyrene, or a composite material made by laminating these with paper), white polyethylene terephthalate substrate, etc. - base film, transparent polyethylene aphthalate base film,
Transparent polyvinyl chloride-based films, polyolefin-coated papers, etc. are used.

Among these, polyolefin-coated paper has been widely used in recent years because it has better heat resistance than other supports and can be produced at low cost. However, when paper, particularly paper with a high moisture content, is used as a support, the heat-diffusible dye in the ink layer tends to escape to the back side of the image-receiving sheet for thermal transfer recording during transfer, which tends to cause so-called transfer omission.

[0010] In addition, a support for thermal transfer recording using a support formed by laminating a thermoplastic resin layer on the surface of paper is comparatively less curable than a support using a plastic film or synthetic paper.
Although it can be said that the occurrence of bleeds is small, it is still not satisfactory.

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

An object of the present invention is to provide an image-receiving sheet for thermal transfer recording that can prevent transfer dropout and curling during image formation while using paper as a component of the support.

[0013]

Means for Solving the Problems In order to achieve the above object, the present invention comprises forming an image-receiving layer on a support, and the support is made of polyethylene containing high-density polyethylene and low-density polyethylene on both sides of the paper. A laminate having a resin mixed layer, and the weight ratio of high density polyethylene to low density polyethylene in the polyethylene resin mixed layer on the image receiving layer side is 0.5 or more, and the polyethylene resin mixture on the side opposite to the image receiving layer. This is an image-receiving sheet for thermal transfer recording, characterized in that the weight ratio of high-density polyethylene to low-density polyethylene in the layer is 1.0 or more.

The present invention will be explained in detail below.

(1) Image-receiving sheet for thermal transfer recording The image-receiving sheet for thermal transfer recording of the present invention can basically consist of a support and an image-receiving layer formed thereon.

-Support- The support in the present invention consists of paper and a polyethylene resin mixed layer formed on both sides of the paper.

1. Paper As the paper constituting the support in the image-receiving sheet for thermal transfer recording of the present invention, paper containing natural pulp as a main component can be used.

[0018] As this natural pulp, wood pulp is preferable. As the wood pulp, chemical pulp, kraft pulp (sulfate pulp), sulfite pulp, bleached pulp, etc. can be suitably used.

Further, the paper may contain additives such as a softener, a paper strength enhancer, a sizing agent, a filler, and a fixing agent during its production. Furthermore, this paper includes paperboard, medium-quality paper,
High quality paper, art paper, coated paper, cast coated paper, kraft paper, synthetic resin emulsion impregnated paper, etc. can be used.

The whiteness of the paper used in the present invention is, for example, Hunter whiteness L≧85, a=-1 to 3, b=-
It is preferably in the range of 1 to -6, especially L≧90, a
It is preferable that b = 0.5 to 1.5 and b = -3 to -5. If the Hunter whiteness of the paper is within the above range,
The clarity of a thermally transferred image can be improved. Hunter whiteness is determined by measuring the spectral reflectance using a spectrophotometer according to JIS Z 8722.
8730. When the paper has a whiteness within this range, the clarity of the image can be improved. In order to bring the whiteness of the paper within the above range, it may be adjusted by bleaching the pulp used for papermaking, using a fluorescent brightener, using a pigment, etc.

The paper used in the present invention preferably has a smoothness of, for example, Bekk smoothness of 100 (unit: seconds) or more. Beck smoothness can be measured using a Beck tester according to JIS P 8119. If paper with low smoothness and rough surface is used, the heat diffusible dye will not be transferred well because the surface of the support will be uneven.
On the other hand, if paper with high smoothness is used, the surface of the support will have fewer irregularities, so it is possible to obtain images of good quality. The smoothness of the paper can be adjusted to a desired value by, for example, performing a calendering process such as on-machine calendering in a paper machine or supercalendering after papermaking.

Further, the paper used in the present invention preferably has a Taber stiffness of 7 or more in the paper-making direction and 3 or more in the perpendicular direction, particularly 10 to 20 in the paper-making direction and 5 to 10 in the perpendicular direction. It is preferable to have one. When the rigidity of the paper is within the above range, the transportability of the image-receiving sheet for thermal transfer recording will be improved and handling will be facilitated. The stiffness is measured using the Taber stiffness meter (
Teledyne Company (USA).

On the other hand, the thickness of the paper used in the present invention is usually 100 μm or more, and preferably 150 to 250 μm.

[0024] The paper used in the present invention is preferably surface-treated, and corona discharge treatment is particularly preferred as the surface treatment. By performing the corona discharge treatment, it is possible to improve the adhesion of the thermoplastic resin layer, which will be described next.

2. Polyethylene resin mixed layer The polyethylene resin mixed layer laminated on both sides of the paper is a polyethylene resin mixed layer containing high density polyethylene and low density polyethylene.

In the present invention, a specific range exists in the weight ratio of high-density polyethylene and low-density polyethylene on the front side and the back side of the paper.

That is, in the present invention, in the polyethylene resin mixed layer on the surface side (image receiving layer side) of the paper, the weight ratio of high density polyethylene (HDPE) to low density polyethylene (LDPE) (HDPE/LDPE) is 0.
．． 5 or more, and the ratio of high density polyethylene (HDP) to low density polyethylene (LDPE) in the polyethylene resin mixed layer on the back side of the paper (the side opposite to the image receiving layer) is
The weight ratio (HDPE/LDPE) of E) is 1.0 or more. When all of these conditions are satisfied, the image-receiving sheet for thermal transfer recording can prevent transfer omission and curling during image formation. On the other hand, if the weight ratio of high-density polyethylene to low-density polyethylene in the polyethylene resin mixed layer on the surface side of the paper is less than 0.5, the image-receiving sheet for thermal transfer recording is likely to suffer from transfer omission during image formation. Further, if the weight ratio of high-density polyethylene to low-density polyethylene in the polyethylene resin mixed layer on the back side of the paper is less than 1.0, the image-receiving sheet for thermal transfer recording tends to curl.

In the present invention, the thickness of the polyethylene resin mixed layer formed on both sides of the paper is preferably within the range of 5 to 35 μm.

3. Manufacturing method of support The support of the image-receiving sheet for thermal transfer recording of the present invention can be manufactured by, for example, extrusion lamination of a polyethylene resin mixture.
It can be manufactured by laminating polyethylene resin mixed layers on both sides of paper.

After the polyethylene resin mixed layers are formed on both sides of the paper, the surface treatment as described above is carried out in order to give the surface of one of the polyethylene resin mixed layers a predetermined surface roughness.

[0031] If necessary, a back coat layer is further formed on the other polyethylene resin mixed layer that has not been adjusted to a predetermined surface roughness.

[0032] The forming components of this back coat layer are as follows:
The following water-soluble resins and water-based emulsion resins can be mentioned. That is, as the water-soluble resin, for example, casein, soy protein, starch, modified starch, polyvinyl alcohol, carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, acrylic ester copolymer, water-soluble polyester, etc. can be suitably used. In addition, as the water-based emulsion resin, for example, styrene-butadiene copolymer latex, methyl methacrylate-butadiene copolymer latex, vinyl acetate emulsion, acrylic emulsion, ethylene copolymer latex, modified resins of these, etc. can be suitably used. Can be done. The above-mentioned water-soluble resin and water-based emulsion resin can be used alone or in combination of two or more. Furthermore, it is also possible to use a mixture of a water-soluble resin and a water-based emulsion resin.

The back coat layer may contain pigments, lubricants, dispersants, etc. The main pigments include, for example, clay, calcium carbonate, aluminum hydroxide, titanium oxide, zinc oxide, plastic pigment, hydrous silicic acid, and barium sulfate. Examples of lubricants include soluble soaps (sodium stearate, ammonium stearate), insoluble soaps, and paraffin waxes. Examples of the dispersant include sodium tripolyphosphate, sodium hexametaphosphate, sodium pyrophosphate, and sodium polyacrylate. In addition, as components other than the above three types, antifoaming agents,
Preservatives, waterproofing agents, etc. can also be used.

[0034] In order to form the back coat layer on the back surface of the recording support, known coating techniques can be employed. However, in order to prepare a coating liquid, water is used as a solvent for water-soluble resins and water-based emulsion resins.

Regarding the thickness of the back coat layer, usually
It is 1 to 30 μm, preferably 1 to 20 μm. If the thickness is less than 1 .mu.m, the effects of the present invention will not be sufficiently exhibited, and if it exceeds 30 .mu.m, the heat-sensitive recording material may become heavy, which is not preferable.

The thickness of the support formed as described above is usually 20 to 300 μm, preferably 30 to 300 μm.
It is μm.

-Image-receiving layer- The image-receiving layer can be formed only from a binder. Moreover, depending on the case, it can also be formed from a binder and various additives.

1. Binder The binder includes, for example, polyvinyl chloride resin,
Copolymer resins of vinyl chloride and other monomers (such as vinyl acetate), polyester resins, acrylic esters, polyvinylpyrrolidone, polycarbonates, cellulose triacetate, styrene acrylate resins, vinyl toluene acrylate resins, polyurethane resins, polyamide resins, Examples include urea resin, polycaprolactone resin, styrene-maleic anhydride resin, and polyacrylonitrile resin.

The various resins mentioned above may be newly synthesized and used, but commercially available products may also be used.

Among the binders, vinyl chloride copolymer resins typified by vinyl chloride-vinyl acetate copolymer resins, polyvinyl chloride resins, polyester resins, and the like are preferred.

The vinyl chloride-vinyl acetate copolymer resin preferably has a vinyl chloride component content of 85 to 97% by weight and a degree of polymerization of about 200 to 800.

The vinyl chloride-vinyl acetate copolymer resin used in the present invention does not necessarily have to be composed only of vinyl chloride components and vinyl acetate components, and may contain vinyl alcohol components and maleic components as long as it does not impede the purpose of the present invention. It may also contain an acid component or the like.

Examples of such vinyl chloride-vinyl acetate copolymers include S-LEC A, S-LEC C, S-LEC M [manufactured by Sekisui Chemical Co., Ltd.], Vinyrite VACH, Vinylyte VYHH, Vinylyte VMCH,
Viny Light VYHD, Viny Light VYLF, Viny Light VYNS, Viny Light VMCC, Viny Light VMCA,
Vinilite VACD, Vinilite VERR, Vinilite VROH (manufactured by Union Carbide), Denkabinir 1000GKT, Denkabinir 1000L, Denkabinir 1000CK, Denkabinir 1000A, Denkabinir 1000LK2, Denkabinir 1000AS,
Denkabinir 1000MT2, Denkabinir 1000
CSK, Denkabinir 1000CS, Denkabinir 10
00GK, Denkabinir 1000GSK, Denkabinir 1000GS, Denkabinir 1000LT3, Denkabinir 1000D, Denkabinir 1000W [manufactured by Denka Kagaku Kogyo Co., Ltd.], and the like.

[0044] As the polyester resin, Vylon 20
0, Byron 290, Byron 600, etc. [manufactured by Toyobo Co., Ltd.], KA-1038C [manufactured by Arakawa Chemical Co., Ltd.]
220, TP235 [all manufactured by Nippon Gosei Co., Ltd.], etc. can be used.

In any case, from the viewpoint of physical properties, resins with glass transition points (Tg) in the range of -20 to 150°C, particularly 30 to 120°C, are suitable as binders for the image-receiving layer.
It is preferable to use a resin having an Mw in the range of .degree.

[0046] In forming the image-receiving layer, the various resins mentioned above utilize their reactive active sites (if there are no reactive active sites, they are added to the resin), and radiation, heat, moisture, catalysts, etc. It may be crosslinked or cured by, for example. In that case, a radiation active monomer such as epoxy or acrylic or a crosslinking agent such as isocyanate can be used.

2. Additives Antioxidants, UV absorbers, light stabilizers, fillers (inorganic fine particles, organic resin particles), and pigments may be added to the additive image-receiving layer. Furthermore, a plasticizer or the like may be added as a sensitizer.

[0048] As the antioxidant, JP-A-59-1
No. 82785, No. 60-130735, JP-A-1-1
Antioxidants described in publications such as No. 27387, and compounds known to improve image durability in photographs and other image recording materials can be mentioned. As the UV absorber and light stabilizer, JP-A-59-15
No. 8287, No. 63-74686, No. 63-1450
No. 89, No. 59-19692, No. 62-229594
Compounds described in publications such as No. 63-122596, No. 61-283595, and JP-A-1-204788,
and compounds known to improve image durability in photographs and other image recording materials.

[0049] 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, alumina, etc., and examples of the organic fine particles include fluororesin particles, guanamine resin particles, acrylic resin particles, silicone resin particles, etc. The following resin particles can be mentioned. These inorganic/organic resin particles vary depending on their specific gravity, but are 0.1
Addition of ~70% by weight is preferred.

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

[0052] As the plasticizer, phthalate esters (
For example, dimethyl phthalate, dibutyl phthalate, dioctyl phthalate, didecyl phthalate, etc.), adipate esters (dioctyl adipate, methyl lauryl adipate, di-2-ethylhexyl adipate, ethyl lauryl adipate, etc.), and other oleic acids. acid esters,
Succinic acid esters, maleic acid esters, sebacic acid esters, citric acid esters, epoxy stearic acid esters, phosphoric acid esters such as triphenyl phosphate and tricresyl phosphate, ethyl phthalylethyl glycolate and glycol esters such as butylphthalyl butyl glycolate.

In the present invention, the total amount of additives added is usually in the range of 0.1 to 50% by weight based on the binder.

(2) Production of image-receiving sheet for thermal transfer recording The image-receiving sheet for thermal transfer recording of the present invention is prepared by preparing a coating liquid for the image-receiving layer by dispersing or dissolving the components forming the image-receiving layer in a solvent; It can be manufactured by a coating method in which the image-receiving layer coating liquid is applied to the surface of the support and dried. It can also be produced by a lamination method or the like in which a mixture containing the components forming the image-receiving layer is melt-extruded and attached to the surface of the support.

[0055] Examples of the solvent used in the above coating method include conventionally known solvents such as water, alcohol, methyl ethyl ketone, toluene, dioxane, and cyclohexanone. When employing the lamination method,
A coextrusion method can also be employed.

The image-receiving layer may be formed over the entire surface of the support, or may be formed on a part of the surface of the support.

The thickness of the image-receiving layer formed on the surface of the support is generally about 2 to 50 μm, preferably about 5 to 20 μm.

In the image-receiving sheet for thermal transfer recording of the present invention, a barrier layer or an intermediate layer (adhesive layer) can be provided between the support and the image-receiving layer.

(3) Ink sheet for thermal transfer recording The ink sheet for thermal transfer recording can basically consist of a support and an ink layer formed thereon.

-Ink layer- The ink layer contains a heat-diffusible dye and a binder as essential components.

1. Heat-diffusible dyes Examples of heat-diffusible dyes include cyan dyes, magenta dyes, and yellow dyes.

[0062] As the cyan dye, JP-A-59-7
No. 8896, No. 59-227948, No. 60-249
No. 66, No. 60-53563, No. 60-130735
No. 60-131292, No. 60-239289, No. 61-19396, No. 61-22993, No. 6
No. 1-31292, No. 61-31467, No. 61-3
No. 5994, No. 61-49893, No. 61-1482
No. 69, No. 62-191191, No. 63-91288
Examples include naphthoquinone dyes, anthraquinone dyes, and azomethine dyes described in publications such as No. 63-91287 and No. 63-290793.

[0063] As the magenta dye, JP-A-59-
No. 78896, JP-A-60-30392, JP-A-60
-30394, JP 60-253595, JP 61-262190, JP 63-5992, JP 63-205288, JP 64-159, JP 64-63194 Examples include anthraquinone dyes, azo dyes, azomethine dyes, etc., which are described in various publications such as No.

[0064] As a yellow dye, JP-A-59-78
No. 896, JP-A-60-27594, JP-A-60-3
No. 1560, JP-A-60-53565, JP-A-61-
Examples include methine dyes, azo dyes, quinophthalone dyes, and anthrisothiazole dyes described in publications such as No. 12394 and JP-A-63-122594.

Particularly preferred as the heat-diffusible dye is a compound having an open-chain or closed-chain active methylene group, and an oxidized product of a p-phenylenediamine derivative or a p-phenylenediamine derivative.
Azomethine dye obtained by a coupling reaction with an oxidized product of an aminophenol derivative and indoaniline obtained by a coupling reaction with an oxidized product of a phenol or naphthol derivative or a p-phenylenediamine derivative or an oxidized product of a p-aminophenol derivative. It is a pigment.

The heat-diffusible dye contained in the ink layer may be any of yellow, magenta, and cyan dyes as long as the image to be formed is monochromatic.

[0067] Depending on the tone of the image to be formed, the composition may contain two or more of the above three types of dyes or other heat-diffusible dyes.

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

2. Binder Binders for the ink layer include cellulose resins such as ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, cellulose acetate, and cellulose acetate butyrate; polyvinyl alcohol, polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone,
polyester, polyvinyl acetate, polyacrylamide,
Examples include vinyl resins such as polyvinyl acetoacetal, styrene resins, styrene copolymer resins, polyacrylic esters, polyacrylic acids, and acrylic acid copolymers, rubber resins, ionomer resins, and olefin resins. Among these resins, polyvinyl butyral, polyvinyl acetoacetal, or cellulose resins, which have excellent acid resistance, are preferred. The above-mentioned various binders can be used alone or in combination of two or more.

The weight ratio of the binder to the heat-diffusible dye is preferably 1:10 to 10:1, particularly preferably 2:8 to 8:2.

3. Other Optional Components Furthermore, various additives may be added to the ink layer as long as they do not impede the object of the present invention.

The additives include fillers such as fine metal powder, silica gel, metal oxide, carbon black, and fine resin powder, mold release agents such as silicone resin and fluororesin, and curing agents that can react with the binder component ( Examples include radiation active compounds such as isocyanates, acrylics, and epoxies.

Furthermore, examples of additives include heat-melting substances for accelerating transfer, such as waxes and higher fatty acid esters, which are described in JP-A-59-106997.

-Support- Any support for the ink sheet for thermal transfer recording may be used as long as it has good dimensional stability and can withstand the heat during recording with a thermal head, but condenser paper, glassine paper, etc. Heat resistant plastic films such as tissue paper, polyethylene terephthalate, polyethylene naphthalate, polyamide, polycarbonate, polysulfone, polyvinyl alcohol, cellophane, polystyrene can be used.

The thickness of the support is preferably 2 to 10 μm, and the support has a subbing layer for the purpose of improving adhesion with the binder and preventing transfer and dyeing of the dye to the support. You can leave it there.

Furthermore, the back side of the support (the side opposite to the ink layer)
A backing layer may be provided for purposes such as running stability, heat resistance, and antistatic properties. The thickness of this backing layer is usually 0.1 to 1 μm.

[0077] There are no particular restrictions on the shape of the support;
For example, it can be of any shape, such as wide sheets or films, or narrow tapes or cards.

(4) Production of ink sheet for thermal transfer recording The ink sheet for thermal transfer recording is prepared by dispersing or dissolving the various components forming the ink layer in a solvent to prepare a coating liquid for forming the ink layer. It can be manufactured by coating this on the surface of a support and drying it. Note that one or more of the binders are used by dissolving them in a solvent or dispersing them in a latex form.

Examples of the solvent include water, alcohols (eg, ethanol, propanol), cellosolves (eg, methyl cellosolve, ethyl cellosolve), and aromatics (eg, methyl cellosolve, ethyl cellosolve).
(e.g., toluene, xylene, chlorobenzene), ketones (e.g., acetone, methyl ethyl ketone), ester solvents (e.g., ethyl acetate, butyl acetate, etc.), ethers (e.g., tetrahydrofuran, dioxane), chlorinated solvents (e.g., chloroform, trichloroethylene)
etc.

[0080] For the above-mentioned coating, conventional methods such as surface sequential coating using a gravure roll, extrusion coating, wire bar coating, roll coating, etc. can be employed.

[0081] The ink layer may be formed as a layer containing a monochromatic heat-diffusible dye on the entire surface or a part of the surface of the support, or may be formed as a layer containing a monochromatic heat-diffusible dye, or a layer containing a yellow ink containing a binder and a yellow dye. A magenta ink layer containing a binder and a magenta dye and a cyan ink layer containing a binder and a cyan dye are formed on the entire surface or a part of the surface of the support in a constant repetition along the plane direction. You can leave it there.

The thickness of the ink layer thus formed is usually 0.2 to 10 μm, preferably 0.3 to 3 μm.
It is μm.

[0083] In the present invention, convenience in use can be made by forming perforations on the ink sheet for thermal transfer recording, or providing detection marks for detecting the positions of areas with different hues. . Note that the ink sheet for thermal transfer recording is not limited to the structure consisting of a support and a heat-sensitive layer formed thereon, and other layers may be formed on the surface of the ink layer. for example,
An overcoat layer may be provided for the purpose of preventing set-off (blocking) of the heat-diffusible dye.

(5) Image formation (thermal transfer recording) To form an image, the ink layer of the ink sheet for thermal transfer recording and the image receiving layer of the image receiving sheet for thermal transfer recording of the present invention are superimposed, and the ink layer and the image receiving layer of the image receiving sheet for thermal transfer recording of the present invention are overlapped. Apply thermal energy imagewise to the interface of the image-receiving layer. In this way, the heat-diffusible dye in the ink layer is vaporized or sublimated in an amount corresponding to the applied thermal energy, and transferred to and received by the image-receiving layer. As a result, an image is formed on the image receiving layer.

[0085] The heat source for providing the thermal energy is as follows:
A thermal head is generally used, but other known devices such as a laser beam, an infrared flash, and a thermal pen can also be used.

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 stages by modulating the voltage or pulse width applied to the thermal head.

[0087] When using laser light as a heat source for providing thermal energy, the provided thermal energy can be changed by changing the amount of laser light and the irradiation area. In this case, in order to facilitate the absorption of laser light, a laser light absorbing material (for example, in the case of a semiconductor laser, carbon black, an infrared absorbing substance, etc.) may be present in the ink layer or near the ink layer. When using a laser beam, it is preferable to bring the ink sheet for thermal transfer recording and the image-receiving sheet for thermal transfer recording into close contact with each other.

If a dot generator incorporating an acousto-optic element is used, thermal energy can be applied depending on the size of halftone dots.

When an infrared flash lamp is used as a heat source for providing thermal energy, heating is preferably performed through a colored layer such as black, as in the case of using laser light. Alternatively, heating may be performed through a pattern or halftone dot pattern that continuously expresses the shading of an image, such as black, or a colored layer such as black and a negative pattern corresponding to the negative of the above pattern. Heating may be performed in combination.

Thermal energy may be applied from the ink sheet side for thermal transfer recording, from the image receiving sheet side for thermal transfer recording, or from both sides, but priority is given to effective use of thermal energy. If so, it is desirable to do so from the ink sheet side for thermal transfer recording.

By the above thermal transfer recording, a one-color image can be recorded on the image-receiving layer of an image-receiving sheet for thermal transfer recording, but according to the method described below, it is possible to obtain a color photographic color image consisting of a combination of each color. You can also do it. For example, by sequentially replacing yellow, magenta, cyan, and, if necessary, black thermal transfer recording sheets and performing thermal transfer for each color, it is possible to obtain a color photo-like color image consisting of a combination of each color. .

In addition, the following method is also effective. That is, instead of using ink sheets for heat-sensitive transfer recording of each color as described above, an ink sheet for heat-sensitive transfer recording is used that has areas pre-painted in each color.

[0093] First, the yellow area is used to thermally transfer the yellow color separation image, and then the magenta area is used to thermally transfer the magenta color separation image. , and, if necessary, a method of thermally transferring the black color image in this order. Although it is possible to obtain a color photographic-like color image with this method as well, this method has the further advantage that there is no need to replace the heat-sensitive sheet for heat-sensitive transfer recording as described above.

[0094]

[Examples] (Examples 1 to 3), (Comparative Examples 1 to 5) Canadian Standard Freeness (JIS P-812
1-76) 20% by weight of softwood bleached sulfite pulp (NBSP) beaten to 250 ml and 80% by weight of hardwood bleached sulfite pulp (LBKP) beaten to 280 ml of Canadian standard freeness are mixed, and this mixed pulp is The material was supplied to a mesh paper machine to make a base paper having a basis weight of 140 g/m2, a tightness of 1.05 g/m2, and a moisture content of 8%. At this time, the following paper-making additives were used in the following amounts based on the absolute dry weight of the pulp.

Papermaking additives:
Cationized starch・・・・・・・・・・・・・・・
・・・・・・2.0% Alkyl ketene dimer resin・・・・・・・・・・・・0.4% Anionic polyacrylamide resin・・・・・・・・・・・・・・・
・0.1% Polyamide polyamine epichlorohydrin resin 0.7% Caustic soda...
・・・・・・・・・Adjust the pH to 7.5.

[0096] Also, counting from the press side of the drying section, 75
% position, mix carboxyl-modified polyvinyl alcohol and sodium chloride at a ratio of 2:1, dissolve this mixture in water, and apply 20g of the 5% size liquid prepared on both sides of the base paper. /m2 coating amount,
Base paper samples E and F were obtained.

Next, corona discharge treatment was applied to the wire side of the paper base paper, and high density polyethylene (density 0.94 g/cm2, MI=8.0) and low density polyethylene (density 0 .92g/cm2, MI=4.
6) at the mixing ratio shown in Table 1 at a resin temperature of 330
Laminated by melt extrusion at ℃, cooled while applying matte molding with a cooling roll to a thickness of 10 μm.
A back coating layer was formed.

Next, the felt surface of the base paper was subjected to corona discharge treatment, and a mixture of high-density polyethylene and low-density polyethylene containing 10% titanium oxide at the mixing ratio shown in Table 1 was melt-extruded at a resin temperature of 320°C. By doing so, they were laminated to form a resin coating layer with a thickness of 10 μm, thereby obtaining a glossy support.

A coating solution for forming an image-receiving layer having the following composition was applied onto the various supports obtained in this manner by a gravure coating method, and dried at a temperature of 130° C. for 5 minutes to form an image-receiving layer with a thickness of 5 μm. Eight types of image receiving sheets for thermal transfer recording were obtained.

Coating liquid for forming image-receiving layer:
Vinyl chloride-isobutyl ether copolymer...
...9.0 parts (manufactured by BASF, Larofl
ex-MP25) Polyester modified silicone resin
・・・・・・・・・・・・・・・ 1.0 part [manufactured by Shin-Etsu Silicon Co., Ltd., X-24-8300] Methyl ethyl ketone・・・・・・・・・・・・・・・・・・・・４０．
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[0101] Next, commercially available FJIX VideoGr
Printing was carried out using a FUJIX video graphic printer using the aphic VP-H ink sheet and the above image-receiving sheet for thermal transfer recording, and the performance was evaluated as follows. The results are shown in Table 1.

Transfer defects: After printing, the sample is left at room temperature, and after three months, transfer defects are observed from the back side. ×: The printed portion is clearly visible from the back side. △...Printed area is slightly visible from the back side. 〇...The printed part is not visible from the back side.

Curl: After printing, the sample is left in a room with a relative humidity of 55% for 20 hours, and the occurrence of curl is evaluated. ×...Curl size. △...Slight curling. 〇... There are almost no curls.

[0104]

[Table 1]

[0105]

[Effect of the invention] The image-receiving sheet for thermal transfer recording of the present invention is
High quality is guaranteed because transfer omissions and curls are prevented during image formation.

Claims (1)

[Claims] Claim 1: An image-receiving layer is formed on a support, the support is a laminate having polyethylene resin mixed layers containing high-density polyethylene and low-density polyethylene on both sides of paper, and the image-receiving layer side The weight ratio of high density polyethylene to low density polyethylene in the polyethylene resin mixed layer on the side opposite to the image receiving layer is 0.5 or more, and the weight ratio of high density polyethylene to low density polyethylene in the polyethylene resin mixed layer on the side opposite to the image receiving layer is 1. An image-receiving sheet for thermal transfer recording, characterized in that it is 0 or more.