JP2001158181A - Laser thermal transfer recording ink sheet and method for forming image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser thermal transfer recording ink sheet capable of obtaining a good image having no laser scanning unevenness even in a laser thermal transfer recording method by a high output multi-channel laser and a method for forming an image. SOLUTION: In the laser thermal transfer recording ink sheet comprising at least a photothermal conversion layer, an intermediate layer and an ink layer on a support, the ink layer contains a carbon black, and a dry adhering amount of a solid content for constituting the ink layer is 0.4 to 1.0 g/m2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink sheet for laser thermal transfer recording which is advantageously used in an image forming method for forming a high-resolution image by irradiating a laser beam. In particular, the present invention relates to color proofing (DDC) in the printing field by laser recording from digital image signals.
P: direct digital color proof) and an ink sheet for laser thermal transfer recording useful for producing a direct digital color proof and an image forming method.

[0002]

2. Description of the Related Art In recent years, in the field of graphic arts, with the introduction of CTP (computer to plate), laser light has been used as a digital color proof capable of obtaining output equivalent to printing by directly inputting digital data. DDCP for outputting fine images
(Direct digital color proof) has been proposed. Among them, the laser thermal transfer recording method using the same pigment as printing has attracted attention as a high-precision proof because it has the same color tone as printing on the actual printing paper, can be calibrated, and it can reproduce halftone dots I have.

[0003] The laser thermal transfer recording system includes a laser thermal transfer recording ink sheet having at least a light-to-heat conversion layer and an ink layer (hereinafter sometimes referred to as a “thermal transfer sheet” or an “ink sheet”) and a laser thermal transfer recording ink sheet. Using an image receiving sheet having an image receiving layer for receiving the ink layer, the ink layer side of the laser thermal transfer recording ink sheet and the image receiving layer side of the image receiving sheet face each other, and irradiating laser light imagewise from the ink sheet side to form the ink layer This is an image forming method in which the image is thermally transferred to the image receiving layer side, and the image is retransferred from an image receiving sheet carrying the image to a permanent support.

In the laser recording method, in order to increase the output speed, the use of a multi-beam laser and a high output laser have recently been performed. What does not happen is required.

Although various ink sheets for laser thermal transfer recording have been proposed, it is difficult for conventional ink sheets for laser thermal transfer recording to make the beam intensity completely flat with a multi-channel laser scanning system. For this reason, there is a problem in that the transfer energy varies in the sub-scanning direction, resulting in an image having laser scanning unevenness.

[0006]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a laser thermal transfer recording ink sheet and an image capable of obtaining a good image without laser scanning unevenness even in a laser thermal transfer recording system using a high-output multi-channel laser. It is to provide a forming method.

[0007]

[Means for Solving the Problems] In an ink sheet for laser thermal transfer recording having at least a light-to-heat conversion layer, an intermediate layer and an ink layer on a support, the ink layer contains carbon black and the solid component constituting the ink layer has a dry amount of 0. An ink sheet for laser thermal transfer recording characterized by having a weight of 4 to 1.0 g / m ² .

[0008] 2. 2. The ink sheet for laser thermal transfer recording according to 1, wherein the intermediate layer contains a photothermal conversion substance.

3. The image is overlaid so that the ink layer surface of the laser thermal transfer recording ink sheet having at least the photothermal conversion layer, the intermediate layer and the ink layer on the support and the image receiving surface of the image receiving sheet having at least the image receiving layer on the support face each other. In the image forming method in which an image is formed by thermally transferring the ink layer to the image receiving layer by exposing and heating as described above, the image is transferred onto a permanent support, and the ink sheet for laser thermal transfer recording according to 1 or 2 is used. An image forming method comprising:

The above object of the present invention is achieved by the following constitution. (Ink Sheet for Laser Thermal Transfer Recording) The ink sheet for laser thermal transfer recording of the present invention comprises at least a light-to-heat conversion layer, an intermediate layer and an ink layer on one surface of a support. It has a configuration in which layers having various functions such as a cushion layer are laminated between the support and the support, and has a back coat layer on the other surface as necessary.

<Support> As the support, for example, paper,
Various papers such as coated paper, synthetic paper (polypropylene, polystyrene, or a composite material obtained by laminating them with paper), vinyl chloride resin sheet, ABS resin sheet (acrylonitrile-butadiene-styrene resin sheet), polyethylene terephthalate film , Polybutylene terephthalate film, polyethylene naphthalate film, polyacrylate film, polycarbonate film, polyetherketone film, polysulfone film, polyethersulfone film, polyetherimide film, polyimide film, polyethylene film, polypropylene film, polystyrene film, syndrome Tactic polystyrene, stretched nylon film, polyacetate film, polymethyl methacrylate film, etc. Layers or various plastic films or sheets obtained by laminating two or more layers thereof, films or sheets formed of various metals, films or sheets formed of various ceramics, and further, such as aluminum, stainless steel, chromium, nickel, etc. Examples thereof include a metal plate and a resin-coated paper laminated or vapor-deposited with a metal thin film. In the present invention,
A conventionally known surface modification treatment may be performed. These surface modification treatments include flame radiation treatment, sulfuric acid treatment, corona discharge treatment, plasma treatment, glow discharge treatment and the like. In the present invention, an adhesive layer may be provided on the support instead of the surface modification treatment. As the adhesive layer, a conventionally known material can be used without any particular limitation. As a method of providing the adhesive layer, water-based resin coating, solvent-based resin coating,
Examples include aqueous latex coating and hot melt coating.

If an image is formed by irradiating a laser beam from the ink sheet side, the support of the ink sheet is preferably transparent. If an image is formed by irradiating a laser beam from the image receiving sheet side, the support of the ink sheet need not be transparent. The thickness of the support is preferably about 6 to 200 μm, more preferably about 2 to 200 μm.
5 to 100 μm.

<Cushion Layer> It is preferable to provide a cushion layer between the support and the ink layer in order to enhance the adhesion between the ink sheet and the image receiving sheet during thermal transfer, or to use a support having a cushion property. The cushion layer is a layer having thermal softening properties or elasticity, and may be made of a material which can be sufficiently softened and deformed by heating, a material having a low elastic modulus, or a material having rubber elasticity. The cushion layer is a layer having a cushioning property, and the elasticity or the penetration can be used as a guideline indicating the cushioning property here. For example, the elastic modulus at 25 ° C. is 1
~ 250kg / mm ² or JIS K2
The penetration specified in 530-1976 is 15-500,
More preferably, about 30 to 300 layers have been confirmed to exhibit suitable cushioning properties for forming a color proof image in the printing field, but the required degree depends on the intended use of the image. It can be selected as appropriate. The cushion layer preferably has a TMA softening point of 70 ° C. or lower, more preferably 60 ° C. or lower. Preferred characteristics of the cushion layer can not necessarily be defined only by the type of the material, but as the characteristics of the material itself is preferable, polyolefin resin, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer,
Polybutadiene resin, styrene-butadiene copolymer (SBR), styrene-ethylene-butene-styrene copolymer (SEBS), acrylonitrile-butadiene copolymer (NBR), polyisoprene resin (IR), styrene-isoprene copolymer (SIS), acrylate copolymer, polyester resin, polyurethane resin,
Acrylic resin, butyl rubber, polynorbornene and the like can be mentioned. Among them, those having a relatively low molecular weight easily satisfy the requirements of the present invention, but are not necessarily limited in relation to the material. The cushion layer can be provided by solvent application, but can also be applied and formed in the form of an aqueous dispersion such as latex or emulsion. In addition,
Water-soluble resins can also be used. These resins can be used alone or in combination as necessary. Further, even with materials other than those described above, favorable characteristics can be imparted to the cushion layer by adding various additives. Examples of such additives include low-melting substances such as wax, and plasticizers. Specific examples include phthalic acid ester, adipic acid ester, glycol ester, fatty acid ester, phosphoric acid ester, chlorinated paraffin, and the like. In addition, various additives described in, for example, "Practical Handbook of Additives for Plastics and Rubber" and Chemical Industries (issued in 1970) can be added. The amount of these additives to be added may be selected in an amount necessary for expressing preferable physical properties in combination with a cushion layer material serving as a base, and is not particularly limited. %, More preferably 5% by mass or less.

In order to provide the cushion layer, coating (blade coater, roll coater, bar coater, curtain coater, gravure coater, etc.) or lamination (eg, extrusion lamination by hot melt, etc.) to provide a certain thickness. Etc.), by laminating films, etc., and further finishing by coating in order to further improve the surface smoothness. The thickness of the cushion layer is 0.3
10 to 10 μm, more preferably 0.5 to 5 μm
It is.

<Light-to-heat conversion layer> The light-to-heat conversion layer is a layer that converts laser light into heat between the support and the ink layer. The light-to-heat conversion layer is generally made of a light-to-heat conversion material (dye, pigment, etc.)
And a binder. Examples of light-to-heat conversion materials that can be used include black pigments such as carbon black, pigments of macrocyclic compounds having absorption in the visible to near-infrared region such as phthalocyanine and naphthalocyanine, and laser absorption of high-density laser recording such as optical disks. Organic dyes (cyanine dyes such as indolenine dyes, anthraquinone dyes, azulene dyes, and phthalocyanine dyes) used as materials, and organic metal compound dyes such as dithiol nickel complexes can be used. The light-to-heat conversion layer is preferably as thin as possible. Therefore, it is preferable to use a cyanine-based dye or a phthalocyanine-based dye exhibiting a large absorption coefficient in a laser light wavelength region.

The material of the binder for the light-to-heat conversion layer is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include acrylic acid such as acrylic acid, methacrylic acid, acrylic acid ester, and methacrylic acid ester. Homopolymers or copolymers of a series of monomers, methyl cellulose, ethyl cellulose, cellulose polymers such as cellulose acetate, polystyrene, vinyl chloride / vinyl acetate copolymer, polyvinyl polymers such as polyvinyl pyrrolidone, polyvinyl butyral, and polyvinyl alcohol, and vinyl compounds Copolymers, polyesters, condensation polymers such as polyamides, rubber-based thermoplastic polymers such as butadiene / styrene copolymers, and polymers obtained by polymerizing and crosslinking photopolymerizable or thermopolymerizable compounds such as epoxy compounds. Can be

When the light-to-heat conversion layer contains a light-to-heat conversion material and a binder, the mass ratio of the two (light-to-heat conversion material:
The binder is preferably 1: 5 to 10: 1, particularly preferably 1: 3 to 3: 1. If the amount of the binder is too small, the cohesive force of the light-to-heat conversion layer is reduced, and when the formed image is transferred to the image receiving sheet,
They tend to be easily transferred together, causing color mixing of images. On the other hand, if the amount of the binder is too large, it is necessary to increase the thickness of the light-to-heat conversion layer in order to achieve a constant light absorptivity, which tends to cause a decrease in sensitivity.

The thickness of the light-to-heat conversion layer is generally 0.05 to 2 μm, preferably 0.1 to 1 μm.
Further, it is preferable that the light-to-heat conversion layer has a light absorption rate of 70% or more at the wavelength of laser light used for optical recording.

Further, by incorporating various release agents into the light-to-heat conversion layer, the releasability between the light-to-heat conversion layer and the ink layer is increased,
Sensitivity can also be improved. As the release agent, a silicone release agent (polyoxyalkylene-modified silicone oil, alcohol-modified silicone oil, etc.), a fluorine-based surfactant, and various other surfactants are effective.

The light-to-heat conversion layer is formed by a conventionally known coating method (blade coater, roll coater, bar coater,
Curtain coater, gravure coater, etc.).

<Intermediate Layer> The intermediate layer is a layer containing a heat-sensitive material that generates gas by the action of heat generated in the light-to-heat conversion layer. As a heat-sensitive material, a compound (polymer or low-molecular compound) which itself decomposes or degrades by heat to generate a gas, or as a characteristic of the material, absorbs or adsorbs a considerable amount of easily vaporizable gas such as moisture. A compound (a polymer or a low molecular compound) or the like can be used. These can be used in combination.

Examples of the polymer which decomposes or degrades by heat to generate a gas include a self-oxidizing polymer such as nitrocellulose, chlorinated polyolefin, chlorinated rubber, polyvinyl chloride, polyvinyl chloride, polyvinylidene chloride and the like. Halogen-containing polymers, acrylic polymers such as polyisobutyl methacrylate in which volatile compounds such as water are adsorbed, cellulose esters such as ethyl cellulose in which volatile compounds such as water are adsorbed, and volatile compounds such as water are adsorbed And naturally occurring high molecular compounds such as gelatin. Examples of the low molecular weight compound which decomposes or changes due to heat to generate a gas include compounds which generate a gas upon exothermic decomposition such as a diazo compound or an azide compound. The decomposition or alteration of the heat-sensitive material due to heat as described above preferably occurs at 280 ° C. or lower, more preferably 230 ° C. or lower.

When a low molecular weight compound is used as the heat-sensitive material in the intermediate layer, it is desirable to combine it with a binder. The binder may be a polymer which itself decomposes or degrades by heat to generate a gas, or an ordinary polymer binder having no such properties. When a heat-sensitive low-molecular compound and a binder are used together, the mass ratio of the former to the latter is preferably 0.02: 1 to 3: 1, and the mass ratio is preferably 0.02: 1 to 3: 1.
More preferably, the ratio is from 05: 1 to 2: 1.

The intermediate layer preferably contains a light-to-heat conversion material. Examples of the light-to-heat conversion substance that can be used include those described for the light-to-heat conversion layer. Among them, carbon black is preferable.

When the intermediate layer contains a light-to-heat conversion material and a heat-sensitive material, the mass ratio of the two (light-to-heat conversion material: heat-sensitive material) is preferably 1:10 to 10: 1, and 1: 1 to 10: 1.
A ratio of 5 to 5: 1 is particularly preferred.

The intermediate layer desirably covers the light-to-heat conversion layer over substantially the entire surface, and preferably has a thickness of 0.03 to 1 μm, and a thickness of 0.05 to 1 μm.
More preferably, it is 0.5 μm.

<Ink Layer> The ink layer usually contains at least a coloring material and a binder for visualizing a recorded image, and further contains other components appropriately selected as necessary. The ink layer is formed so as to be melted or softened at the time of thermal transfer so as to be peelable and transferable from the support.

The dye or pigment contained in the ink layer can be appropriately selected from conventionally known dyes and pigments. Such dyes include, for example, Disperse Red 1, Disp.
erase Yellow 3, Disperse Ye
lower 23, Disperse Yellow 6
Azo dyes such as 0, Disperse Violet
28, Disperse Blue 14, Disp
erse Blue 26, Disperse Red
4, Disperse Red 60, Dispers
e Anthraquinone dyes such as Yellow 13;
And Disperse Yellow 54, Disp
erase Yellow 61, Disperse Y
yellow 82, Disperse Blue 20
And the like.

The pigment is not particularly limited and may be appropriately selected from various known pigments. Examples thereof include carbon black, azo-based, phthalocyanine-based, quinacridone-based, thioindigo-based, and anthra-based pigments. Quinones and isoindolines are preferred. In the present invention, it is preferable to contain carbon black.

The content of carbon black in the ink layer is preferably from 10 to 70 parts by mass, and more preferably from 15 to 60 parts by mass.
Parts by mass are more preferred. If the content is less than 10 parts by mass, a desired image density may not be obtained, and if it exceeds 70 parts by mass, the dispersion stability of the pigment may be deteriorated.

These pigments may be used alone or in combination of two or more, and a known dye may be used in combination for adjusting the hue. As the average particle size of the pigment, for example, 70% or more of all the pigments is preferably 1.0 μm or less. If the average particle size of the pigment is too large, the transparency of the overlapping portion of each color during color reproduction may be impaired.

The pigment can be dispersed in the binder by dissolving the binder in a solvent selected as appropriate, and adding and mixing the pigment therein.
Various dispersing methods used in the coatings field can be applied.

Examples of the binder include the following thermoplastic polymers. Methylcellulose, ethylcellulose, cellulose derivatives such as cellulose triacetate, homopolymers or copolymers of acrylic monomers such as acrylic acid, methacrylic acid, acrylates and methacrylates, polyvinyl chloride, vinyl acetate, polyvinyl butyral , Vinyl polymers such as polyvinyl formal, styrene polymers such as polystyrene and styrene / maleic acid copolymer, rubber polymers such as polybutadiene and polyisoprene, and polyolefins such as polyethylene and ethylene / vinyl acetate copolymer and copolymers thereof. Coalescence, phenolic resin, ionomer resin.

Among the above resins, those having a Tg (glass transition temperature) in the range of 30 to 120 ° C. are preferable.
For example, polyvinyl butyral or an acrylic polymer is preferable. Use of polyvinyl butyral is advantageous in terms of transfer sensitivity, dot shape, and pigment dispersion stability. The average molecular weight of the thermoplastic polymer is 5000
It is desirably in the range of -100,000.

The content of the binder in the ink layer is preferably from 25 to 80 parts by mass, more preferably from 30 to 60 parts by mass.

If the content of the binder is less than 25% by mass, the transfer sensitivity is not sufficient, and image defects may occur. If it exceeds 80% by mass, adhesion resistance and blocking properties may be deteriorated.

The above-mentioned other components are not particularly limited, and those appropriately selected from known additives such as various polymers, adhesion improvers, surfactants, release agents, plasticizers and the like can be used in the present invention. In the range that does not impair the purpose, specifically 1 to 15
About parts by mass can be used. For example, in the ink layer, from the viewpoint of improving the releasability and thermal sensitivity of the ink layer from the support at the time of thermal printing, various release agents and softeners are used in an amount of 1 to 20% by mass based on the total amount of the ink layer. Parts may be added. More specifically, for example, palmitic acid, higher fatty acids such as stearic acid, fatty acid metal salts such as zinc stearate,
Fatty acid esters or partially saponified products thereof, fatty acid derivatives such as fatty acid amides, higher alcohols, derivatives such as esters of polyhydric alcohols, waxes such as paraffin wax, carnauba wax, montan wax, beeswax, wood wax, and candelilla wax. , Low molecular weight polyethylene having a viscosity average molecular weight of about 1,000 to about 10,000,
Polyolefins such as polypropylene and polybutylene,
Or olefins, α-olefins and maleic anhydride, organic acids such as acrylic acid and methacrylic acid, low molecular weight copolymers with vinyl acetate and the like, low molecular weight oxidized polyolefins, halogenated polyolefins, lauryl methacrylate, stearyl methacrylate and the like Methacrylates having long alkyl side chains, acrylates or acrylates having a perfluoro group, methacrylates alone or copolymers with vinyl monomers such as styrene, polydimethylsiloxane, poly Low molecular weight silicone resins such as diphenylsiloxane and silicone-modified organic substances, and furthermore, ammonium salts having long-chain aliphatic groups, cationic surfactants such as pyridinium salts, or similarly anions having long-chain aliphatic groups, Nonionic surfactant, Such Furoro based surfactant may be added. As the other components, one kind may be used alone, or two or more kinds may be used in combination.

In the present invention, the dry amount of the solid component constituting the ink layer is 0.4 to 1.0 g / m ² , preferably 0.5 to 0.8 g / m ² .

(Image-Receiving Sheet) Examples of the image-receiving sheet that can be used in the present invention include those that form an image by receiving an ink layer peeled imagewise from the ink sheet for laser thermal transfer recording. Usually, the image receiving sheet is provided with at least one or more image receiving layers on one surface of the support, but may be formed only from the support. It is desirable that the image receiving sheet has appropriate heat resistance and excellent dimensional stability so that an image can be appropriately formed.

As the support of the image receiving sheet, those similar to those described for the ink sheet can be used.

The image receiving layer formed on the support comprises a binder, various additives which are added as required, and a mat material. In some cases, it is formed only with a binder. As a binder for an image receiving layer having good image receiving properties, adhesives such as a polyvinyl acetate emulsion adhesive, a chloroprene adhesive, an epoxy resin adhesive, a natural rubber, a chloroprene rubber, a butyl rubber, a polyacrylate ester, Adhesives such as nitrile rubbers, polysulfides, silicone rubbers, rosins, vinyl chlorides, petroleum resins and ionomer resins, recycled rubbers, SBR, polyisoprene, polyvinyl ether and the like can be mentioned.

When the image formed on the image receiving layer is retransferred to another recording medium by heating and / or pressurizing, a resin having a relatively small polarity (small SP value) is used as the image receiving layer. Is particularly preferred. For example, polyethylene, polypropylene, ethylene-vinyl chloride copolymer, polybutadiene resin, ethylene-acrylic copolymer, vinyl chloride resin, various modified olefins, and the like. The thickness of the image receiving layer is usually 1 to 10 μm, but is not limited to the case where the cushion layer is used as the image receiving layer. The cushion layer described in the ink sheet can be used as the cushion layer. In addition, if necessary, a release layer may be provided between the image receiving layer and the support, more preferably between the image receiving layer and the cushion layer, and a back coat layer, an antistatic layer and the like may be provided on the surface of the support opposite to the image receiving layer. it can.

(Thermal transfer recording system) The transfer of the ink layer may be any of a thermal fusion transfer, an ablation transfer, and a sublimation transfer. The laser beam is converted into heat, and the ink is transferred to the image receiving sheet using the heat energy. And a method of forming an image on an image receiving sheet. In the present invention, the fusion / ablation method is preferable in that an image having a hue similar to printing is produced.

[0044]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited to these examples. (Preparation of Image Receiving Sheet Sample) A first image receiving layer coating solution and a second image receiving layer coating solution having the following compositions were prepared. (First image receiving layer coating solution) Vinyl chloride / vinyl acetate copolymer (MPR-TSL, manufactured by Nissin Chemical Co., Ltd.) 25 parts Dibutyl octyl phthalate (DOP, manufactured by Daihachi Chemical Co., Ltd.) 12 parts Surfactant (MegaFac F) -177, manufactured by Dainippon Ink and Chemicals, Inc. 4 parts Methyl ethyl ketone 75 parts (coating solution for the second image receiving layer) Polyvinyl butyral (Denka butyral # 2000-L, manufactured by Denki Kagaku Kogyo) 16 parts N, N-dimethylacrylamide / butyl Acrylate copolymer 4 parts Surfactant (Megafac F-177, manufactured by Dainippon Ink and Chemicals, Inc.) 0.5 part n-propyl alcohol 200 parts 100 μm thick polyethylene terephthalate film (T100: manufactured by Mitsubishi Chemical Polyester) Apply the above-mentioned coating solution for the first image receiving layer on one surface of, and dry at 100 ° C. Thickness was formed first image receiving layer of 25 [mu] m. Next, on the first image receiving layer, the above-mentioned coating solution for the second image receiving layer is further coated in the same manner so that the dry film thickness becomes 2 μm.
After drying at 0 ° C., an image receiving sheet sample was prepared.

Example 1 (Preparation of Ink Sheet Sample 1) 1) Preparation of Photothermal Conversion Layer Coating Solution The following components were mixed with stirring with a stirrer to prepare a photothermal conversion layer coating solution. (Coating solution for photothermal conversion layer) Infrared absorbing dye (IR-820, manufactured by Nippon Kayaku Co., Ltd.) 5 parts Binder (polyamic acid: PAA-A, manufactured by Mitsui Toatsu Chemicals) 40 parts Methyl ethyl ketone 1000 parts 1-methoxy-2- Propanol 1000 parts Surfactant (Megafac F-177P, manufactured by Dainippon Ink and Chemicals, Inc.) 1 part The above polyamic acid (PAA-A) (obtained by the reaction of an aromatic tetracarboxylic dianhydride with a diamine). Is a 25% by weight solution of N, N-dimethylacetamide. 2) Formation of a light-to-heat conversion layer on the surface of the support The above-mentioned coating solution for a light-to-heat conversion layer was applied to one surface of a 100 μm-thick polyethylene terephthalate film (manufactured by Mitsubishi Chemical Polyester Corporation, T100) using a wire bar. The resulting film thickness was 0.1 μm. 3) Preparation of coating solution for intermediate layer The following components were mixed with stirring with a stirrer to prepare coating solution 1 for intermediate layer. (Intermediate layer coating liquid 1) Nitrocellulose (Type HIG120, manufactured by Asahi Kasei Corporation) 1.3 parts Methyl ethyl ketone 26 parts Propylene glycol monomethyl ether acetate 40 parts Toluene 92 parts Surfactant (Megafac F-177, Dainippon Ink & Chemicals, Inc.) 4) Formation of an intermediate layer on the surface of the light-to-heat conversion layer The above-mentioned intermediate layer coating solution 1 was applied to the surface of the light-to-heat conversion layer using a wire bar. The thickness of the intermediate layer is 0.1μ
m. 5) Preparation of Ink Layer Coating Liquid The following components were dispersed for 2 hours using a paint shaker (manufactured by Toyo Seiki Co., Ltd.) to prepare a pigment dispersion mother liquor 1. Then, the obtained dispersed mother liquor 1 was diluted with n-propyl alcohol and measured with a particle size measuring device (laser light scattering method). As a result, 70% by mass or more of the pigment was 18% by mass.
It was in the range of 0-300 nm. (1 composition of pigment dispersion mother liquor) Polyvinyl butyral (Denka butyral # 2000-L, manufactured by Denki Kagaku Kogyo Co., Ltd.) 12 parts Color material (carbon black pigment, type MA-1, manufactured by Mitsubishi Chemical Corporation) 12 parts Dispersing aid (Solsperse S 0.80 parts n-propyl alcohol 110 parts glass beads 100 parts The following components were mixed with stirring with a stirrer to prepare an ink layer coating liquid 1. (Ink layer coating liquid 1) Pigment dispersion mother liquor 1 20 parts n-propyl alcohol 60 parts Surfactant (Megafac F-177P, manufactured by Dainippon Ink and Chemicals, Inc.) 0.05 parts 6) Ink on intermediate layer surface Formation of Layer On the surface of the intermediate layer, the ink layer coating liquid 1 is applied with a wire bar and dried to form an ink layer so as to have a dry amount of a solid component of 0.4 g / m ^2. Then, an ink sheet sample 1 was prepared.

Example 2 (Preparation of Ink Sheet Sample 2) An ink sheet sample 2 was prepared in the same manner as in Example 1 except that the following intermediate layer coating liquid 2 was used as the intermediate layer coating liquid. (Intermediate layer coating liquid 2) Nitrocellulose (Type HIG120, manufactured by Asahi Kasei Corporation) 1.2 parts Carbon black pigment (Type MA-1, manufactured by Mitsubishi Chemical Corporation) 0.5 parts Methyl ethyl ketone 26 parts Propylene glycol monomethyl ether acetate 40 parts Toluene 92 parts Surfactant (Megafac F-177, manufactured by Dainippon Ink and Chemicals, Inc.) 0.01 part Example 3 (Preparation of Ink Sheet Sample 3) The drying amount of the solid component of the ink layer was 0.6 g / m. except for using ^2, to prepare an ink sheet sample 3 in the same manner as in example 1.

Example 4 (Preparation of Ink Sheet Sample 4) The following components were dispersed for 2 hours using a paint shaker (manufactured by Toyo Seiki Co., Ltd.) to prepare a pigment dispersion mother liquor 2. Then, the obtained dispersed mother liquor 2 was diluted with n-propyl alcohol, and measured with a particle size measuring device (laser light scattering method).
More than 70% by weight of the particles were in the range from 180 to 300 nm. (Pigment dispersion mother liquor 2 composition) Polyvinyl butyral (Denka butyral # 2000-L, manufactured by Denki Kagaku Kogyo) 12 parts Coloring material (carbon black pigment, type MA-1, manufactured by Mitsubishi Chemical Corporation) 10 parts Coloring material (cyan pigment, CI Pigment Blue 15: 4) 1 part Color material (magenta pigment CI Pigment Red 57: 1) 1 part Dispersing aid (SOLSPERS S-20000, manufactured by ICI Japan) 0.8 part n-propyl Alcohol 110 parts Glass beads 100 parts The following components were mixed with stirring with a stirrer to prepare an ink layer coating liquid 2. (Ink layer coating liquid 2) Pigment dispersion mother liquor 2 20 parts n-propyl alcohol 60 parts Surfactant (Megafac F-177P, manufactured by Dainippon Ink and Chemicals, Inc.) 0.05 parts The above ink as an ink layer coating liquid Using the layer coating solution 2,
An ink sheet sample 4 was prepared in the same manner as in Example 1 except that the amount of the solid component in the ink layer with drying was set to 1.0 g / m ² .

Example 5 (Preparation of Ink Sheet Sample 5) The following intermediate layer coating liquid 3 was used as the intermediate layer coating liquid, and the above-mentioned ink layer coating liquid 2 was used as the ink layer coating liquid. An ink sheet sample 5 was prepared in the same manner as in Example 1, except that the amount of drying was set to 1.0 g / m ² . (Intermediate layer coating liquid 3) Nitrocellulose (Type HIG120, manufactured by Asahi Kasei Corporation) 1.2 parts Infrared absorbing dye (IR820B, manufactured by Nippon Kayaku Co., Ltd.) 0.3 parts Methyl ethyl ketone 26 parts Propylene glycol monomethyl ether acetate 40 parts Toluene 92 parts Surfactant (Megafac F-177, manufactured by Dainippon Ink and Chemicals, Inc.) 0.01 part Example 6 (Preparation of ink sheet sample 6) Using ink layer coating liquid 2 described above as ink layer coating liquid, ink layer Ink sheet sample 6 was produced in the same manner as in Example 1, except that the amount of the solid component with drying was 0.8 g / m ² .

Comparative Example 1 (Preparation of Ink Sheet Sample 7) An ink sheet sample 7 was prepared in the same manner as in Example 1, except that the amount of the solid component in the ink layer with drying was 0.2 g / m ² .

Comparative Example 2 (Preparation of Ink Sheet Sample 8) An ink sheet sample 8 was prepared in the same manner as in Example 1 except that the amount of the solid component in the ink layer with drying was 1.4 g / m ² .

Comparative Example 3 (Preparation of Ink Sheet Sample 9) The following components were dispersed in a paint shaker (manufactured by Toyo Seiki Co., Ltd.) for 2 hours to prepare a pigment-dispersed mother liquor 3. (Pigment dispersion mother liquor 3 composition) Polyvinyl butyral (Denka butyral # 2000-L, manufactured by Denki Kagaku Kogyo Co., Ltd.) 12 parts Coloring material (cyan pigment, CI Pigment Blue 15: 4) 12 parts Dispersing aid (Solsperse S- 0.8000 n-propyl alcohol 110 parts Glass beads 100 parts The following components were mixed with a stirrer under stirring to prepare an ink layer coating liquid 3. (Ink layer coating liquid 3) Pigment dispersion mother liquor 3 20 parts n-propyl alcohol 60 parts Surfactant (Megafac F-177P, manufactured by Dainippon Ink and Chemicals, Inc.) 0.05 parts The above ink as an ink layer coating liquid Using the layer coating liquid 3,
An ink sheet sample 9 was prepared in the same manner as in Example 1, except that the amount of the solid component in the ink layer with drying was 0.5 g / m ² .

Comparative Example 4 (Preparation of Ink Sheet Sample 10) Except that the above-mentioned ink layer coating liquid 3 was used as the ink layer coating liquid and the amount of the solid component of the ink layer with drying was 0.3 g / m ² . An ink sheet sample 10 was produced in the same manner as in Example 1.

Comparative Example 5 (Preparation of Ink Sheet Sample 11) Except that the above-mentioned ink layer coating liquid 3 was used as the ink layer coating liquid and the amount of the solid component of the ink layer with drying was 1.2 g / m ² . An ink sheet sample 11 was produced in the same manner as in Example 1. <Laser scanning unevenness evaluation method> An image receiving sheet sample and each of the ink sheet samples 1 to 11 were combined, and an exposure machine (EV-laser-proof manufactured by Konica Corporation) was used.
r), exposure was performed under an exposure condition of an exposure surface power of 100 mW / ch, and a rotation speed of 400 to 600 rpm to output a solid image. Then, a laminator (EV-EV manufactured by Konica Corp.) was used.
The image was re-transferred to art paper by a laminator) to obtain a final image. The obtained images were visually evaluated for laser scanning unevenness, and classified according to the following criteria. Table 1 shows the results.

A: No laser scanning unevenness Δ: Slight laser scanning unevenness X: Laser scanning unevenness

[0055]

[Table 1]

As is clear from Table 1, it is understood that the use of the ink sheet for laser thermal transfer recording and the image forming method of the present invention can provide a good image with no laser scanning unevenness.

[0057]

According to the present invention, even in a laser thermal transfer recording system using a high-power multi-channel laser,
An ink sheet for laser thermal transfer recording and an image forming method capable of obtaining a good image without laser scanning unevenness can be provided.

Claims (3)

[Claims] 1. An ink sheet for laser thermal transfer recording having at least a light-to-heat conversion layer, an intermediate layer and an ink layer on a support, wherein the ink layer contains carbon black and a solid component constituting the ink layer is dried. An ink sheet for laser thermal transfer recording, wherein the coating weight is 0.4 to 1.0 g / m ² . 2. The ink sheet for laser thermal transfer recording according to claim 1, wherein the intermediate layer contains a photothermal conversion material. 3. The ink layer surface of a laser thermal transfer recording ink sheet having at least a light-to-heat conversion layer, an intermediate layer and an ink layer on a support, and an image receiving surface of an image receiving sheet having at least an image receiving layer on the support. The image forming method according to claim 1, wherein the ink layer is thermally transferred to the image receiving layer by imagewise exposing and heating to form an image, and then the image is transferred onto a permanent support. An image forming method using an ink sheet for thermal transfer recording.