JP2022113924A - Heat-sensitive recording material - Google Patents

Abstract

To provide a heat-sensitive recording material that can give a high-contrast image by irradiation with infrared laser light.SOLUTION: A heat-sensitive recording material has, on a light-transmitting support, at least an infrared absorption layer, a heat-sensitive recording layer, and a protective layer in the stated order. The infrared absorption layer contains an infrared absorption dye with a ratio ε(830)/ε(365) of 4.0 or more between a molar extinction coefficient ε(830) at 830 nm and a molar extinction coefficient ε(365) at 365 nm. The heat-sensitive recording layer contains non-photosensitive organic silver salts and is substantially free of photosensitive silver halides.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a heat-sensitive recording material that forms an image by irradiation with an infrared laser beam, and more particularly to a heat-sensitive recording material that is suitable for the production of an original.

2. Description of the Related Art A wet processing image forming method using a silver halide photosensitive material has been generally used for a long time as a high quality image recording method used for preparing a block copy. However, wet processing image forming methods require disposal of waste liquids such as developing solutions and fixing solutions, which imposes a large environmental burden. At present, image forming systems such as inkjet printers, electrophotography, dye thermal transfer systems, and the like have been put to practical use. However, with these dry image forming methods, it is difficult to obtain a so-called high-contrast block copy having excellent light-shielding properties in image areas and excellent light transmittance in non-image areas.

As a dry image forming method capable of obtaining a high contrast equivalent to that of a wet processing image forming method using a silver halide light-sensitive material, a thermal head or an infrared laser is applied to a heat-sensitive recording material having a heat-sensitive recording layer on a support. A method of forming an image using light may be mentioned. Among them, the thermal recording method using an infrared laser beam is superior from the viewpoint of high-density recording and high-quality recording. As a heat-sensitive recording material that can be drawn with an infrared laser beam, for example, JP-A-6-194781 (Patent Document 1) describes a thermally reducible silver source and a reducing agent for silver ions that can record high-density images. , a dye that absorbs laser light in the wavelength range of about 500 to 1100 nm, and a heat-sensitive recording material containing a polymerizable binder are disclosed. A recordable thermal recording material for infrared laser light is disclosed which contains an organic silver salt, an organic silver salt developer, an infrared absorbing dye, and a water-soluble binder. Further, Japanese Patent Application Laid-Open No. 2001-10229 (Patent Document 3) contains a non-photosensitive organic silver salt, a reducing agent for silver ions, a binder, a color tone adjusting agent, and an absorber that absorbs radiation in the wavelength range of 750 to 1100 nm. Therefore, a thermochromic image-forming material having a low ultraviolet density and little residual color is disclosed.

However, in recent years, there has been a demand for higher density and higher definition images. Insufficient or excessive light irradiation to the material may cause fine images such as fine lines and small dots to be missing, and there has been a demand for further improvement in the contrast of thermal recording materials that form images by irradiating infrared laser light. .

JP-A-6-194781 JP-A-10-29377 JP-A-2001-10229

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat-sensitive recording material capable of obtaining a high-contrast image when irradiated with an infrared laser beam.

The above problems are solved by the following inventions.
An infrared absorbing dye having a molar extinction coefficient ε(830) at 830 nm and a molar extinction coefficient ε(365) at 365 nm having a ratio ε(830)/ε(365) of 4.0 or more is contained on a light-transmitting support. a heat-sensitive recording layer containing a non-photosensitive organic silver salt and substantially free of photosensitive silver halide; and a protective layer in this order.

The present invention can provide a heat-sensitive recording material capable of obtaining a high-contrast image by irradiation with an infrared laser beam.

The details of the present invention will be described below.

The heat-sensitive recording material of the invention has a light-transmitting support. Examples of such light-transmitting supports include resin films such as polyethylene terephthalate, polyethylene naphthalate, cellulose nitrate and polycarbonate, and inorganic materials such as glass. In the present invention, the light-transmitting support means a support having a total light transmittance of 60% or more, more preferably 70% or more. Further, the haze value of the light-transmitting support is preferably 10% or less. The light-transmitting support may have known layers such as an easy-adhesion layer, a hard coat layer and an antistatic layer. Although the thickness of the light-transmitting support in the invention is not particularly specified, it is preferably 50 to 300 μm from the viewpoint of handling.

In the heat-sensitive recording material of the present invention, the molar absorption coefficient ε(830) at 830 nm and the molar absorption coefficient ε(365) at 365 nm have a ratio of ε(830)/ε(365) of 4 on the above-mentioned light-transmitting support. It has an infrared absorbing layer containing an infrared absorbing dye of 0.0 or more. The infrared absorbing dye in the present invention refers to a dye having absorption in the wavelength range of 600 to 1500 nm, preferably having an absorption maximum in the wavelength range of 650 to 1100 nm, and having an absorption maximum in the wavelength range of 750 to 1100 nm. is more preferred. In addition, the infrared absorbing dye in the present invention has small absorption in the wavelength range of 350 to 450 nm where there is an emission peak in the ultraviolet region of high-pressure mercury lamps and chemical lamps, that is, ε(830)/ε(365) described above. When it is 4.0 or more, it is possible to obtain a heat-sensitive recording material capable of obtaining a high-contrast image by irradiation with an infrared laser beam, and the upper limit is not particularly limited. Examples of such dyes include compounds having a polymethine skeleton such as squarylium, cyanine, merocyanine, and bis(aminoaryl)polymethine. Specifically, compounds represented by the following general formulas (1) to (3) are listed. However, the present invention is not limited to these.

R ¹ to R ¹⁰ in general formulas (1) to (3) are substituents, hydrogen atom, alkyl group, aryl group, alkoxy group, acyl group, ester group, amide group, halogen atom, hydroxy group, thiol group. , a thioether group, a sulfonyl group, and the like. These may be the same substituents or different substituents, and may be combined with other substituents to form a ring structure. X 1 ⁻ represents a negatively charged atom or atomic group, and includes halogen ions, oxoacids such as perchlorate ions, tetrafluoroborate, hexafluorophosphate, alkyl and arylsulfonates. Specific examples include compounds such as exemplary compounds (1) to (3), but are not limited to these.

The content of the infrared absorbing dye is preferably 0.1 to 20 mass % with respect to the total solid content of the infrared absorbing layer.

In the present invention, the infrared absorbing layer preferably contains a binder component together with the infrared absorbing dye described above. Thermoplastic resins are preferred as such binder components, and typified by, for example, cellulose derivatives such as hydroxyethyl cellulose and hydroxypropyl cellulose, acrylic resins, polyester resins, polyurethane resins, vinyl chloride resins, vinyl acetate resins, polyolefin resins, and polyvinyl butyral resins. Polyvinyl acetal resin, polyvinyl alcohol resin and the like are exemplified. These binder components may be used by dissolving them in water or an organic solvent, or latex in which hydrophobic polymer solids are dispersed in the form of fine particles, or polymer molecules in which micelles are formed and dispersed. In the present invention, the above binder component preferably forms a transparent film after drying. Moreover, these binder components may be used in combination of two or more kinds of mutually compatible resins, if necessary.

The infrared absorbing layer of the heat-sensitive recording material of the present invention is prepared by preparing an infrared absorbing layer coating solution containing the above-described infrared absorbing dye and binder component, and coating the infrared absorbing layer coating solution on the above-described light-transmitting support. , preferably formed by drying. Further, the film thickness of the infrared absorption layer is preferably 0.01 to 5.0 μm.

For the purpose of improving coatability, the infrared absorption layer coating solution may contain various surfactants. Nonionic surfactants, anionic surfactants, and cationic surfactants may be used without any particular limitation.

The infrared absorbing layer of the heat-sensitive recording material of the present invention contains a non-photosensitive organic silver salt, a reducing agent, and a toning agent, which will be described later, from the viewpoint of improving the efficiency of image formation by infrared laser light and suppressing the increase in haze. , and stabilizers. The term "substantially free" as used herein means that the total amount of each component described above is less than 5 mass % of the solid content of the infrared absorbing layer.

The heat-sensitive recording layer of the heat-sensitive recording material of the present invention contains an organic silver salt. The organic silver salt is a non-photosensitive organic silver salt, and is reduced by heating with a reducing agent to be described later to form a silver image. Specifically, gallic acid, oxalic acid, behenic acid, stearic acid, palmitic acid, lauric acid, etc., as described in Research Disclosure, Sections 17029(II) and 29963(XVI) of Research Disclosure concerning photothermographic materials. silver salts of organic acids; silver salts of carboxyalkylthiourea such as 1-(3-carboxypropyl) thiourea and 1-(3-carboxypropyl)-3,3-dimethylthiourea; formaldehyde, acetaldehyde, butyraldehyde and the like Complexes of silver with polymer reaction products of aldehydes and aromatic carboxylic acids such as salicylic acid, benzoic acid, 3,5-dihydroxybenzoic acid and 5,5-thiodisalicylic acid; 3-(2-carboxyethyl) -silver salts or complexes of thiones such as 4-hydroxymethyl-4-thiazoline-2-thione, 3-carboxymethyl-4-methyl-4-thiazoline-2-thione; imidazole, pyrazole, urazole, 1,2, silver salts or complexes of nitrogen-containing heterocycles selected from 4-triazole, 1H-tetrazole, 3-amino-5-benzylthio-1,2,4-triazole and benzotriazole; silver such as saccharin and 5-chlorosalicylaldoxime; Salt; includes silver salts of mercaptides and the like. Of these, fatty acid silver having 10 or more carbon atoms is preferred, and silver stearate and silver behenate are particularly preferred.

In the present invention, the content of the organic silver salt contained in the thermosensitive recording layer can be appropriately adjusted depending on the maximum density required for use as a block copy, and is 0.5 to 0.5 per square meter in terms of silver. 2.0 g is preferred.

The heat-sensitive recording layer in the invention does not substantially contain silver halide. The term "substantially free" as used herein means that the amount of silver halide contained in the heat-sensitive recording layer is less than 1% by mass based on the total solid content of the heat-sensitive recording layer. A heat-sensitive recording material is obtained in which an increase in transmission density in a non-image area during storage and during normal use of the recording material is suppressed, and a high-contrast image can be plated.

In the present invention, the heat-sensitive recording layer preferably contains a reducing agent. Such reducing agents include pyrogallol, 4-stearoylpyrogallol, isopropyl gallate, ethyl 3,4-dihydroxybenzoate, 2,5-dihydroxybenzoic acid, etc., described in US Pat. Polyhydroxyindanes described in Japanese Patent No. 3,440,049 or JP-A-06-317870, and dihydroxybenzoic acid derivatives described in JP-A-2001-328357 are preferred.

The content of the above-mentioned reducing agent can vary widely depending on the type of reducing agent and the type of organic silver salt, but it is preferably 0.1 to 3.0 mol per 1 mol of the organic silver salt. More preferably 5 to 2.0 mol. For various purposes, two or more of the above reducing agents may be used in combination.

The heat-sensitive recording layer of the heat-sensitive recording material of the present invention preferably contains a so-called toning agent known in the field of thermography or photothermography. Examples of the toning agent are known in Research Disclosure Nos. 17029(V) and 29963(XXII) of the above-mentioned photothermographic materials. Specifically, imides represented by phthalimide, 3-mercapto -mercapto compounds represented by 1,2,4-triazole, phthalazine, phthalazone, 4-methylphthalic acid, tetrachlorophthalic acid and phthalic acid derivatives represented by their anhydrides, 1,3-benzoxazine-2, Benzoxazine derivatives such as 4-diones are included. For various purposes, two or more of the above-described toning agents may be used in combination.

The heat-sensitive recording layer of the heat-sensitive recording material of the present invention contains various accelerators, stabilizers and their precursors for the purpose of suppressing or promoting the formation of image silver and improving the storage stability of the heat-sensitive recording material before and after image formation. It may contain a body. Specifically, benzotriazole, 5-methylbenzotriazole, 5-chlorobenzotriazole, 2-mercaptobenzotriazole, 2-mercaptobenzimidazole, 2-mercaptobenzothiazole, 2, which are known as photographic stabilizers and inhibitors, -mercaptobenzoxazole, 4-hydroxy-6-methyl-1,3,3a,7-tetrazaindene, 1-phenyl-5-mercaptotetrazole, 2-amino-5-mercapto-1,3,4-thiadiazole, It can be selected from 3-mercapto-5-phenyl-1,2,4-triazole, 4-benzamido-3-mercapto-5-phenyl-1,2,4-triazole and the like. For various purposes, two or more of the above accelerators and stabilizers may be used in combination.

The heat-sensitive recording layer of the heat-sensitive recording material of the present invention preferably contains a binder component. A thermoplastic resin is preferable as such a binder component, and for example, the same thermoplastic resin as the binder component of the infrared absorbing layer described above can be preferably used. Moreover, as the binder component, two or more kinds of resins compatible with each other may be used in combination, if necessary.

The content of the binder component contained in the heat-sensitive recording layer is preferably 10 to 70 mass % with respect to the total solid content of the heat-sensitive recording layer.

It is preferable that the binder component described above does not contain free halide ions such as chloride ions and bromide ions. Halide ions react with silver ions of the organic silver salt to form photosensitive silver halide, which causes the heat-sensitive recording material of the present invention to deteriorate in light resistance. Specifically, it is preferably 100 ppm or less with respect to the binder component amount.

In the present invention, the heat-sensitive recording layer is preferably adjacent to the above-mentioned infrared absorption layer without any other layer interposed therebetween. image can be obtained. As a method for forming the heat-sensitive recording layer, a heat-sensitive recording layer coating solution containing the above-described organic silver salt, reducing agent, toning agent, binder component, etc. is prepared, and the heat-sensitive recording layer coating solution is applied to the above-described infrared absorption layer. It is preferably formed by coating and drying on the surface. The film thickness of the thermosensitive recording layer is preferably 0.5 to 20 μm.

For the purpose of improving coatability, the thermosensitive recording layer coating solution may contain various surfactants. Nonionic surfactants, anionic surfactants, and cationic surfactants may be used, and are not particularly limited.

The heat-sensitive recording material in the present invention has a protective layer on the heat-sensitive recording layer for the purpose of protecting the heat-sensitive recording layer from contact with the photosensitive material, impact during handling, and the like. The protective layer preferably contains a resin component, and specific resin components include gelatin, acrylic resin, polyester resin, polyurethane resin, vinyl chloride resin, vinyl acetate resin, polyolefin resin, polyvinyl alcohol resin, polyvinyl acetal resin, and the like. are exemplified. These resins and aqueous dispersions of resins are commercially available and readily available. Moreover, a cross-linking agent may be contained in order to improve the scratch resistance of the protective layer.

In the present invention, the protective layer may contain various matting agents for the purpose of enhancing vacuum properties and scratch resistance. In forming the protective layer, the matting agent is preferably used by dispersing it in the protective layer. A high-speed stirrer such as a homodisper is suitable for dispersing the matting agent.

Matting agents can be either organic or inorganic. Examples of organic matting agents include silicone, polytetrafluoroethylene, polymethyl methacrylate, and polyacrylate, and examples of inorganic matting agents include silica, alumina, talc, and mica. Examples of commercially available products include Tospearl (registered trademark) 120, 130, 145, and 2000B sold by Momentive Performance Materials Japan LLC as silicone resin-based matting agents, and AGC Si Tech as silica-based matting agents. Sunsphere (registered trademark) H-31, H-51, NP-30, and the like, which are sold by Co., Ltd., can be exemplified. Although these are single fine particles, as the form of the matting agent, both single fine particles and fine particle aggregate particles in which fine particles are aggregated may be used.

The amount of the matting agent contained in the protective layer is preferably 0.5 to 40% by mass, more preferably 1 to 30% by mass, based on the amount of the resin component.

As a method for forming a protective layer in the present invention, a protective layer coating solution containing the above-mentioned resin component, matting agent, etc. is prepared, the protective layer coating solution is applied on the above-mentioned thermosensitive recording layer, and dried. preferably formed. For the purpose of improving coatability, the thermosensitive recording layer coating solution may contain various surfactants. Nonionic surfactants, anionic surfactants, and cationic surfactants may be used, and are not particularly limited.

The film thickness of the protective layer of the heat-sensitive recording material of the present invention can vary widely depending on the type of resin component used and the desired heat-sensitive sensitivity, but is selected from the range of 0.1 to 10 μm.

In the present invention, there are no particular restrictions on the method of coating the infrared absorbing layer, the heat-sensitive recording layer, and the protective layer described above. D. Cohen, E. B. Gutoff, "Modern Coating and Drying Technology", WILEY-VCH, Inc.; A variety of coating methods can be selected, such as those described in New York, 1992. Furthermore, simultaneous coating of multiple layers by a slide coating method using a slit-type die coater, or a tandem coating method that repeats coating and drying processes by combining the same or different types of coater equipment is also useful in terms of improving productivity. Especially preferred.

The heat-sensitive recording material of the present invention may further include an easy-adhesion layer, a heat-insulating layer, etc. An intermediate layer, etc., is placed between the infrared absorption layer, the heat-sensitive recording layer, and the protective layer, and an easily peelable layer, etc., is placed on the protective layer, and charged on the opposite side of the light-transmitting support as seen from the heat-sensitive recording layer and the protective layer. Although it may have a protective layer or the like, it is preferable that the infrared absorption layer and the heat-sensitive recording layer are adjacent to each other as described above.

An image can be obtained by using the heat-sensitive recording material described above and irradiating an infrared laser beam imagewise from the protective layer side of the heat-sensitive recording material. Examples of the infrared laser light source include semiconductor lasers, He--Ne lasers, Ar lasers, carbon dioxide lasers, YAG lasers and fiber lasers. In the heat-sensitive recording material of the present invention, the density of the image portion can be changed by changing the energy of the irradiated infrared laser light and the exposure time.

The present invention will be described below using examples, but the present invention is not limited by these descriptions. In addition, "%" in description is a mass standard.

<Example 1>

<Preparation and Application of Infrared Absorbing Layer Coating Solution>
2-Butanone 81 g, methanol 24 g, polyvinyl butyral resin (Butvar (registered trademark) B-79, manufactured by Eastman Chemical Japan Co., Ltd.) 9.0 g, an infrared absorbing dye Exemplified compound (3) (Showa Denko Co., Ltd. 0.45 g of ε(830)/ε(365)=6.2, manufactured by IRT, was added to prepare an infrared absorbing layer coating solution. This infrared absorption layer coating solution was applied to a 100 μm thick PET base (total light transmittance of 92%, haze value of 4%) so that the film thickness after drying was 1.2 μm, and dried at 50 ° C. let me ε(830) and ε(365) were obtained by measuring the absorption spectrum of a 2-butanone solution of an infrared absorbing dye with a UV-visible spectrophotometer UV-2600 (manufactured by Shimadzu Corporation, using a quartz cell with an optical path length of 1 cm). Measured and calculated.

<Preparation of silver behenate dispersion>
20 g of silver behenate crystals and 22 g of polyvinyl butyral resin (Butvar B-79) were added to 175 g of 2-butanone, and a bead mill apparatus (DYNO-MILL KD20B type, manufactured by Willie & Bacchofen) was filled with zirconia beads of 0.65 mm in diameter. ) to obtain a silver behenate dispersion (average particle size: 0.6 μm).

<Preparation and Application of Heat-Sensitive Recording Layer Coating Solution>
45 g of 2-butanone, 2.4 g of polyvinyl butyral resin (Butvar B-79), 30 g of the silver behenate dispersion described above, 1.5 g of ethyl 3,4-dihydroxybenzoate as a reducing agent, and 0.5 g of tetrachlorophthalic anhydride. 6 g and 1.2 g of phthalazone were added to prepare a heat-sensitive recording layer coating solution. This heat-sensitive recording layer coating liquid was applied onto the infrared absorption layer already obtained as described above so as to have a silver conversion value of 1.1 g/m ² and dried at 80°C to form a heat-sensitive recording layer. did. The amount of silver halide contained in the resulting heat-sensitive recording layer was less than 0.1% with respect to the total solid content of the heat-sensitive recording layer.

<Preparation and Application of Protective Layer Coating Solution>
Beamset (registered trademark) 3702 (manufactured by Arakawa Chemical Industries, Ltd.; a mixture containing an epoxy acrylate polymer, a polyfunctional acrylate compound, and a photopolymerization initiator) as a photocurable resin in 15.0 g of 2-butanone, solid content 59%) was added to obtain 30 g (including 8.4 g of the solid content of the binder component) of the protective layer coating liquid. This protective layer coating solution was applied onto the thermosensitive recording layer so that the film thickness after drying was 3.0 μm, dried at 60° C., and then irradiated with a high-pressure mercury lamp at a distance of 10 cm and a conveying speed of 5 m/s. A heat-sensitive recording material of Example 1 was obtained by curing the protective layer by irradiation under the condition of min.

<Example 2>
Preparation and application of the infrared absorbing layer coating solution of Example 1 were carried out in the same manner as in Example 1, except that the infrared absorbing layer coating solution was applied so that the film thickness of the infrared absorbing layer after curing was 1.5 μm. A thermal recording material of Example 2 was obtained.

<Example 3>
In the preparation and application of the infrared absorbing layer coating liquid of Example 1, the infrared absorbing layer coating liquid was applied so that the film thickness of the infrared absorbing layer after curing was 1.9 μm. A thermal recording material of Example 3 was obtained.

<Example 4>
In the preparation and application of the protective layer coating solution of Example 1, 9 g of polyvinyl butyral resin (Butvar B-79) was added to 81 g of 2-butanone and 24 g of methanol to prepare a protective layer coating solution. A heat-sensitive recording material of Example 4 was obtained in the same manner as in Example 1 except that the coating was applied so as to have a thickness of 6 μm.

<Example 5>
In the preparation and application of the infrared absorbing layer coating solution of Example 1, 0.45 g of Exemplified Compound (1) (ε(830)/ε(365) = 18.5) was added instead of IRT as an infrared absorbing dye. A heat-sensitive recording material of Example 5 was obtained in the same manner as in Example 1 except that the absorption layer coating liquid was applied so that the film thickness after drying was 1.5 μm.

<Example 6>
In the preparation and application of the infrared absorbing layer coating solution of Example 1, 0.45 g of Exemplified Compound (1) was added instead of IRT as an infrared absorbing dye, and the film thickness of the infrared absorbing layer coating solution after drying was 2.3 μm. A heat-sensitive recording material of Example 6 was obtained in the same manner as in Example 1, except that the coating was carried out as follows.

<Comparative Example 1>
Comparison was made in the same manner as in Example 1 except that the infrared absorption layer was not applied and the thermosensitive recording layer was applied on a PET base having a thickness of 100 μm (total light transmittance 92%, haze value 4%). A thermal recording material of Example 1 was obtained.

<Comparative Example 2>
In Example 1, the infrared absorbing layer was not applied, and 0.045 g of Exemplified Compound (3) was added as an infrared absorbing dye in the preparation and application of the thermosensitive recording layer coating solution, and a 100 μm thick PET base (total light transmittance of 92 A heat-sensitive recording material of Comparative Example 2 was obtained in the same manner as in Example 1, except that the composition was applied onto the surface of the material (%, haze value 4%).

<Comparative Example 3>
In Example 1, without coating the infrared absorption layer, the thermosensitive recording layer coating liquid was coated on a 100 μm thick PET base (total light transmittance 92%, haze value 4%), and the protective layer coating liquid was prepared and For coating, a protective layer coating solution was prepared by adding 9 g of polyvinyl butyral resin (Butvar B-79) and 0.45 g of Exemplified compound (3) as an infrared absorbing dye to 81 g of 2-butanone and 24 g of methanol. A heat-sensitive recording material of Comparative Example 3 was obtained in the same manner as in Example 1 except that the coating was applied so that the film thickness after drying was 1.6 μm.

<Comparative Example 4>
In the preparation and application of the infrared absorbing layer coating solution of Example 1, IX-2-IR-14 (manufactured by Nippon Shokubai Co., Ltd., phthalocyanine dye, ε(830)/ε(365) was used instead of IRT as the infrared absorbing dye. A heat-sensitive recording material of Comparative Example 4 was obtained in the same manner as in Example 1 except that 0.07 g of )=2.6) was added.

The heat-sensitive recording materials of Examples 1 to 6 and Comparative Examples 1 to 4 thus obtained were subjected to thermal CTP setter (manufactured by Guangzhou Amsky Technology Co Ltd, AURA600E) at a drum rotation speed of 300 rpm and an exposure output of 200 mW to 800 mW. , an image (20 mm (width)×200 mm (length)) having 50 minute dots (negative image) with a diameter of 20 μm and a solid portion was formed.

<Transmission density measurement>
The transmission densities of solid images and non-image areas of the heat-sensitive recording materials of Examples 1 to 6 and Comparative Examples 1 to 4 after the image formation were measured with X-Rite (registered trademark) 361T (UV mode) manufactured by X-Rite. . Table 1 shows the exposure output value, solid area transmission density (Dmax), and non-image area transmission density (Dmin) at which the maximum transmission density of each thermosensitive recording material was obtained.

<Return performance evaluation>
Using the heat-sensitive recording material after image formation as a mask film, a negative type resin plate (Treleaf (registered trademark) MF95DIIJ, thickness 0.95 mm, manufactured by Toray Industries, Inc.) was prepared by a plate making machine (manufactured by Takano Kikai Seisakusho Co., Ltd.). , Takano Processor DX-A4), and the rebound characteristics of the heat-sensitive recording material were evaluated. Of the 50 micropoints with a diameter of 20 μm described above, ◯ indicates that 49 or more remain on the resin plate after plate making, △ indicates that 30 to 48 remain, and 0 to 29 remain. The evaluation results are shown in Table 1, with X indicating that there is a failure.

As is clear from the results in Table 1, the present invention provides a heat-sensitive recording material capable of providing high-contrast images.

Claims (1)

An infrared absorbing dye having a molar extinction coefficient ε(830) at 830 nm and a molar extinction coefficient ε(365) at 365 nm having a ratio ε(830)/ε(365) of 4.0 or more is contained on a light-transmitting support. a heat-sensitive recording layer containing a non-photosensitive organic silver salt and substantially free of photosensitive silver halide; and a protective layer in this order.