JPH0692074A - Thermal recording material - Google Patents

Abstract

(57) [Summary] [Object] The present invention can record necessary visible information arbitrarily, and at the same time, can arbitrarily form a pattern which cannot be visually discerned in a random portion, which is more secure. The purpose is to provide high recording materials. A first thermosensitive coloring layer containing, on a support, an electron-accepting compound and an electron-donating compound which forms a dye having absorption in the near infrared region by reaction with the electron-accepting compound; By sequentially laminating an accepting compound and a second thermosensitive coloring layer containing an electron-donating compound which forms a dye having no absorption in the near infrared region by reaction with the electron-accepting compound, the desired heat-sensitive compound is obtained. Obtain recording material.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The present invention is capable of arbitrarily forming an image having an absorption in the visible light portion and an image having an absorption in the near infrared portion by heating, is difficult to forge / reproduce, and distinguishes between true and false. The present invention relates to a heat-sensitive recording material that can be easily processed.

[0002]

2. Description of the Related Art With the recent widespread use of various types of cards and the like, there are various risks of forgery, falsification, and unauthorized use, and there is a constant demand for new fraud prevention techniques.

Various methods have been proposed for preventing counterfeiting or falsification of securities, boarding tickets, commuter tickets, horse tickets, prepaid cards and the like. As a magnetic method, a magnetic recording layer is provided on the base material, and when recording information, the magnetic density or the signal encoding method is changed so that it cannot be read or written by a general device, such as a magnetic bar code. There are a method of providing fixed data and a method of providing a magnetic shield layer on the magnetic recording layer. In addition, as a method that uses vision, a method that uses a hologram that makes a three-dimensional image appear when light is applied by using interference of light, uses a fluorescent ink to make a pattern print so that it is invisible, and uses ultraviolet light. When it hits, it fluoresces,
There is a method of performing hidden character printing so that the pattern can be visually confirmed. Also, the one utilizing optical reading is widely used. For example, there is a method of recording image information on the surface of a card or the like and reading the information by a barcode, OMR, OCR or the like. However, since the image information itself can be visually confirmed, it is possible to easily forge or falsify.

As an improved version of these, Japanese Patent Laid-Open No. 63-
116286, JP-A-64-87397,
Japanese Patent Application Laid-Open No. 4-70394 discloses a material such as a dye that absorbs light in a specific wavelength range other than the visible light range in a stripe shape,
A method of printing or applying in the form of a bar code is shown. In such a method, it is difficult to visually determine the stripe-shaped or barcode-printed or applied portion, and it can be read only by an optical reading device that detects light in a specific wavelength range other than the visible light range. Cannot be forged or tampered with.

[0005]

However, even with these methods, it is necessary to print a pattern on a card or the like in advance, so that there is a problem that the pattern is inevitably limited to a specific limited pattern due to the complexity of printing. Contains. Further, in order to put visible information, a thermosensitive coloring layer, a thermal transfer image receiving layer and the like must be provided separately. The present invention is capable of arbitrarily recording necessary visible information, and at the same time, it is possible to arbitrarily form a pattern which can be discriminated by an optical reading device in a random portion although it cannot be discriminated by visual observation.
The purpose is to provide a new recording material with higher security.

[0006]

The present inventor has conducted various studies on recording materials satisfying the above conditions in a heat-sensitive recording system characterized by miniaturization and maintenance-free of the device. A first thermosensitive coloring layer containing an acceptor compound and an electron-donating compound which forms a dye having absorption in the near infrared region by reaction with the electron-accepting compound,
Laminating sequentially an electron-accepting compound and a second thermosensitive coloring layer containing an electron-donating compound that forms a dye having substantially no absorption in the near infrared region by reaction with the electron-accepting compound. Thus, the intended heat-sensitive recording material could be obtained.

In the heat-sensitive recording material of the present invention, necessary visible information is printed and recorded on an arbitrary portion on the second thermosensitive coloring layer by a thermal printing method such as thermal head printing or laser irradiation. At the same time, the first thermosensitive coloring layer allows a pattern having absorption in the near infrared region to be formed in an arbitrary portion in a random state. That is, when printed at low temperature, the second thermosensitive coloring layer in the upper layer develops color and can be recognized as visible information, and when printed at high temperature, the second thermosensitive coloring layer in the upper layer and the first thermosensitive coloring layer in the lower layer. Since and develop color at the same time, a dye image having absorption in the near infrared region is formed along with recognition as visible information. The near-infrared part indicates a wavelength region of 700 nm to 1300 nm. That is, since the dye having absorption in the near infrared region formed in the first thermosensitive coloring layer has absorption in this wavelength region, it is possible to read mechanically in this wavelength region, but in the second thermosensitive coloring layer. The formed dye having substantially no absorption in the near infrared region has almost no absorption in this wavelength region and does not hinder mechanical reading in this wavelength region. Forgery
In order to enhance the effect of tampering prevention, it is more preferable that the image of visible information and the image having absorption in the near-infrared part have the same hue because it is difficult to identify.

That is, the second upper layer which provides a visible information image
Of the heat-sensitive color-developing layer and the color-developing hue of the first heat-sensitive color-developing layer in the lower layer which gives an image having absorption in the near infrared region are the same, or the second heat-sensitive color-developing layer of the upper layer is colored in black Preferably. Even if the hue of the first thermosensitive coloring layer in the lower layer is not particularly black, it is sufficient if it is visually mixed with the black of the second thermosensitive coloring layer in the upper layer and cannot be visually identified as black in the visible information image. .

Among the conventional heat-sensitive recording materials, there is known a two-color heat-sensitive recording material in which two kinds of electron-donating compounds are contained in different heat-sensitive color-forming layers to form two different hues depending on the difference in printing temperature. Has been. For example, JP-A-49-65239
It is disclosed in the publication. However, this two-color heat-sensitive recording material is characterized by only forming two different hues and obtaining a visible image, and has no security.

Specific examples of the electron-donating compound forming a dye having absorption in the near infrared region, which is contained in the first thermosensitive coloring layer under the thermosensitive recording material according to the present invention, are shown below.
It is not limited to these.

3,6-bis (dimethylamino) fluorene-9-spiro-3 '-(6'-dimethylamino) phthalide, 3,6-bis (diethylamino) fluorene-9
-Fluorene compounds such as spiro-3 '-(6'-diethylamino) phthalide, 3,3-bis [2'-(p-dimethylaminophenyl) -2 '-(p-methoxyphenyl) vinyl] -4, 5,6,7-Tetrachlorophthalide, 3,3-bis [2 '-(p-dimethylaminophenyl) -2'-(p-methoxyphenyl) vinyl] -4,
5,6,7-Tetrabromophthalide, 3,3-bis [2
'-(P-Methoxyphenyl) -2'-(p-pyrrolidinophenyl) vinyl] -4,5,6,7-tetrachlorophthalide, bis (p-dimethylaminostyryl) -p-
Toluenesulfonylmethane, bis (p-diethylaminostyryl) -p-toluenesulfonylmethane, bis (p-dimethylaminostyryl) -benzenesulfonylmethane, 1,1-bis [2 ', 2'-(p-dimethylaminophenyl) Vinyl] -2,2-dinitrileethane and other divinyl compounds,

2-Methyl-6-p- (p-dimethylaminophenyl) aminoanilinofluorane, 2-methoxy-6-p- (p-dimethylaminophenyl) aminoanilinofluorane, 2-chloro-6 -P- (p-dimethylaminophenyl) aminoanilinofluorane, 2-diethylamino-6-p- (p-diethylaminophenyl)
Aminoanilinofluorane, 2-phenyl-6-p-
(P-Phenylaminophenyl) aminoanilinofluorane, 2-benzyl-6-p- (p-phenylaminophenyl) aminoanilinofluorane, 3-diethylamino-6-p- (p-diethylaminophenyl) aminoani Rinofluorane, 2-chloro-3-methyl-6-p-
Examples thereof include fluoran compounds such as (p-phenylaminophenyl) aminoanilinofluorane. These electron donating compounds may be used alone or in admixture of two or more.

The electron-donating compound for forming a dye having no absorption in the near infrared region, which is contained in the second heat-sensitive color forming layer as the upper layer of the heat-sensitive recording material according to the present invention, is generally used for pressure-sensitive recording paper or heat-sensitive recording paper. There are things that have been done. Specific examples are shown below, but the invention is not limited thereto.

3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (crystal violet lactone), 3,3-bis (p-dimethylaminophenyl) phthalide, 3- (p-dimethylaminophenyl) ) -3- (1,2-Dimethylindol-3-yl)
Phthalide, 3- (p-dimethylaminophenyl) -3-
(2-Methylindol-3-yl) phthalide, 3-
(P-Dimethylaminophenyl) -3- (2-phenylindol-3-yl) phthalide, 3,3-bis (1,
2-Dimethylindol-3-yl) -5-dimethylaminophthalide, 3,3-bis (1,2-dimethylindol-3-yl) -6-dimethylaminophthalide, 3,
3-bis (9-ethylcarbazol-3-yl) -5-
Dimethylaminophthalide, 3,3-bis (2-phenylindol-3-yl) -5-dimethylaminophthalide, 3-p-dimethylaminophenyl-3- (1-methylpyrrol-2-yl) -6 -Triarylmethane compounds such as dimethylaminophthalide,

Diphenylmethane compounds such as 4,4'-bis (dimethylaminophenyl) benzhydrylbenzyl ether, N-chlorophenylleukoauramine and N-2,4,5-trichlorophenylleucoauramine, rhodamine B anilino. Lactam, rhodamine Bp
-Chloroanilinolactam, 3-diethylamino-7-
Dibenzylaminofluorane, 3-diethylamino-7
-Octylaminofluorane, 3-diethylamino-7
-Phenylfluorane, 3-diethylamino-7-chlorofluorane, 3-diethylamino-6-chloro-7-
Methylfluorane, 3-diethylamino-7- (3,4
-Dichloroanilino) fluorane, 3-diethylamino-7- (2-chloroanilino) fluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3
-(N-ethyl-N-tolyl) amino-6-methyl-7
-Anilinofluorane, 3-piperidino-6-methyl-
7-anilinofluorane, 3- (N-ethyl-N-tolyl) amino-6-methyl-7-phenethylfluorane,
3-diethylamino-7- (4-nitroanilino) fluorane, 3-dibutylamino-6-methyl-7-anilinofluorane, 3- (N-methyl-N-propyl) amino-6-methyl-7-anilino Fluoran, 3- (N-
Ethyl-N-isoamyl) amino-6-methyl-7-anilinofluorane, 3- (N-methyl-N-cyclohexyl) amino-6-methyl-7-anilinofluorane,
3- (N-ethyl-N-tetrahydrofuryl) amino-
Xanthene-based compounds such as 6-methyl-7-anilinofluorane,

Thiazine compounds such as benzoyl leuco methylene blue and p-nitrobenzoyl leuco methylene blue, 3-methylspirodinaphthopyran, 3-ethylspirodinaphthopyran, 3,3'-dichlorospirodinaphthopyran, 3-benzylspiro Dinaphthopyran, 3-methylnaphtho- (3-methoxybenzo) spiropyran, 3
Examples thereof include spiro compounds such as -propylspirobenzopyran, which may be used alone or in combination of two or more.

The electron-accepting compound contained in the first heat-sensitive coloring layer as the lower layer and the second heat-sensitive coloring layer as the upper layer in the heat-sensitive recording material according to the present invention is the same kind as long as it is an acidic substance generally used in heat-sensitive paper. However, different types are not particularly limited. As these electron accepting compounds, for example, polyvalent metal salts such as phenol derivatives, aromatic carboxylic acid derivatives, N, N'-diarylthiourea derivatives, and zinc salts of organic compounds can be used.

Particularly preferred are funol derivatives, specifically p-phenylphenol, p-hydroxyacetophenone, 4-hydroxy-4'-methyldiphenylsulfone, 4-hydroxy-4'-isopropoxydiphenylsulfone. , 4-hydroxy-4'-benzenesulfonyloxydiphenyl sulfone, 1,1-bis (p-hydroxyphenyl) propane, 1,1-bis (p-hydroxyphenyl) pentane, 1,1-bis (p-hydroxyphenyl) ) Hexane, 1,1-bis (p-hydroxyphenyl) cyclohexane, 2,2-
Bis (p-hydroxyphenyl) propane, 2,2-bis (p-hydroxyphenyl) hexane, 1,1-bis (p-hydroxyphenyl) -2-ethylhexane,
2,2-bis (3-chloro-4-hydroxyphenyl)
Propane, 1,1-bis (p-hydroxyphenyl)-
1-phenylethane, 1,3-di- [2- (p-hydroxyphenyl) -2-propyl] benzene, 1,3-di- [2- (3,4-dihydroxyphenyl) -2-propyl] benzene , 1,4-di- [2- (p-hydroxyphenyl) -2-propyl] benzene,

4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfone, 3,
3'-dichloro-4,4'-dihydroxydiphenyl sulfone, 3,3'-diallyl-4,4'-dihydroxydiphenyl sulfone, 3,3'-dichloro-4,4'-
Dihydroxydiphenyl sulfide, 2,2-bis (4
-Hydroxyphenyl) methyl acetate, 2,2-bis (4
-Hydroxyphenyl) butyl acetate, 4,4'-thiobis (2-t-butyl-5-methylphenol), 2,
2'-bis (4-hydroxyphenylthio) diethyl ether, 1,7-di (4-hydroxyphenylthio)-
3,5-Dioxaheptane, benzyl p-hydroxybenzoate, chlorobenzyl p-hydroxybenzoate, 4-
Examples thereof include dimethyl hydroxyphthalate, benzyl gallate, stearyl gallate, salicylanilide, and 5-chlorosalicylanilide. These can be used alone or in combination of two or more. These electron-accepting compounds are 10 to 40 relative to the electron-donating compounds.
It is preferable to use 0% by weight, further 30 to 250
It is more preferable to use the weight percent.

The binder used in the first and second thermosensitive coloring layers of the thermosensitive recording material according to the present invention includes starches, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, gelatin, casein, polyvinyl alcohol, modified polyvinyl alcohol and poly. Sodium acrylate, acrylic acid amide / acrylic acid ester copolymer, acrylic acid amide / acrylic acid ester / methacrylic acid terpolymer, alkali salt of styrene / maleic anhydride copolymer, ethylene / maleic anhydride copolymer Water-soluble polymer such as combined alkali salt, polyvinyl acetate, polyurethane, polyacrylic acid ester, styrene / butadiene copolymer, acrylonitrile / butadiene copolymer methyl acrylate / butadiene copolymer, ethylene / vinyl acetate Such as latex, such as a copolymer thereof. It is used in an amount of 1 to 40% by weight, preferably 3 to 20% by weight, based on the total solid content of the thermosensitive coloring layer excluding the binder.

The first of the heat-sensitive recording materials according to the present invention,
And, a heat fusible substance may be contained in order to improve the thermal response of the second thermosensitive coloring layer. 60 ℃ ~ 180
Those having a melting point of ℃ are preferable, and especially 80 ℃ ~ 140
Those having a melting point of ° C are preferred. It is also possible to use a sensitizer which is used in general thermal recording paper. Examples of these compounds include waxes such as N-hydroxymethylstearic acid amide, stearic acid amide, and palmitic acid amide, naphthol derivatives such as 2-benzyloxynaphthalene, and biphenyl derivatives such as p-benzylbiphenyl and 4-allyloxybiphenyl. 1,2-bis (3
-Methylphenoxy) ethane, 2,2'-bis (4-methoxyphenoxy) diethyl ether, bis (4-methoxyphenyl) ether and other polyether compounds, diphenyl carbonate, dibenzyl oxalate, bis (p-oxalate)
Examples thereof include carbonic acid such as methylbenzyl) ester and oxalic acid diester derivatives, which can be used alone or in combination. In order to obtain sufficient thermal response, it is preferable to use 30 to 700% by weight, more preferably 50 to 550% by weight, of the electron donating compound.

Various additives can be added to each thermosensitive coloring layer. Examples of the pigment include diatomaceous earth, talc, kaolin, calcined kaolin, calcium carbonate, magnesium carbonate, titanium oxide, zinc oxide, silicon oxide, aluminum hydroxide and other inorganic pigments, and urea-formalin resin and other organic pigments. Inorganic and organic infrared absorbers that heat-convert laser light, as well as higher fatty acid metal salts such as zinc stearate and calcium stearate for the purpose of preventing head wear and sticking, paraffin, oxidized paraffin, polyethylene, polyethylene oxide, stearin. Waxes such as acid amide and castor wax, dispersants such as sodium dioctylsulfosuccinate, ultraviolet absorbers such as benzophenone and benzotriazole, surfactants, fluorescent dyes and the like are added as necessary.

Paper is mainly used as the support for the heat-sensitive recording material according to the present invention. In addition to paper, various non-woven fabrics, woven fabrics, synthetic resin films, laminated papers, synthetic papers, metal foils and the like, or these A composite sheet obtained by combining the above can be arbitrarily used according to the purpose. Also,
In order to protect the thermosensitive recording layer, an overcoat layer consisting of a single layer or a plurality of layers is provided on the second thermosensitive coloring layer which is an upper layer, or a single layer or a plurality of layers are provided between the first thermosensitive recording layer and the support. It is also possible to provide an undercoat layer containing a pigment or a resin formed of a layer, or to provide an intermediate layer between the first thermosensitive coloring layer and the second thermosensitive coloring layer. Further, a back coat layer may be provided on the surface of the support opposite to the surface on which the thermosensitive recording layer is provided for the purpose of preventing curling and antistatic, and various known methods for producing general thermosensitive recording materials are known. Technology can be used.

[0024]

When the heat-sensitive recording material according to the present invention is printed with low energy, the heat-sensitive color-forming layer located in the upper layer develops a color and a visible image having absorption only in the visible light region is obtained. When printing with higher energy, the thermosensitive coloring layer located in the lower layer together with the upper layer develops a color, and a visible image having absorption in the near infrared region is obtained. Since a normal thermal head or laser light irradiation can be used for printing, it is possible to form a visible image having absorption only in the visible light region and a visible image having absorption in the near infrared region at an arbitrary portion. If the hues of the two colors are the same or close to each other, it is impossible to visually distinguish them. If a reading device using near infrared light is used, the two can be clearly distinguished. That is, it is possible to arbitrarily form a pattern that cannot be visually identified in a random state. Therefore, if it is forged or altered, it can be easily identified and forged.
It is possible to provide a new recording material that is more effective in preventing alteration and has higher security.

[0025]

EXAMPLES Next, the present invention will be described in more detail by way of examples. The parts and% shown below are based on weight.

Example 1 Preparation of heat-sensitive recording material (A) Preparation of heat-sensitive coating liquid for the first heat-sensitive recording layer 3,6-bis (dimethylamino) as an electron-donating compound in which the color developing material has absorption in the near infrared region. 25 parts of fluorene-9-spiro-3 '-(6'-dimethylamino) phthalide was pulverized with 80 parts of 2.5% aqueous polyvinyl alcohol solution by a ball mill for 24 hours to obtain a leuco dye dispersion. Next, 40 parts of 2,2-bis (p-hydroxyphenyl) propane as an electron-accepting compound was pulverized with a ball mill for 60 hours together with 60 parts of a 2.5% aqueous polyvinyl alcohol solution to obtain a developer dispersion. As a sensitizer, 55 parts of 2-benzyloxynaphthalene was crushed together with 120 parts of a 2.5% aqueous solution of polyvinyl alcohol in a ball mill for 24 hours to obtain a dispersion liquid.

After mixing the above-mentioned three kinds of dispersions, with stirring,
100 parts of 50% dispersion of calcium carbonate, 170 parts of 10% aqueous solution of polyvinyl alcohol, and 124 parts of water were added to prepare a heat-sensitive coating liquid for the first heat-sensitive recording layer.

(B) Preparation of heat-sensitive coating liquid for second heat-sensitive recording layer 3-di-n-butylamino is used as an electron-donating compound in which the color former has absorption in the visible light region and does not have absorption in the near infrared region. 2.5 parts of 6-methyl-7-anilinofluorane was added to 2.5
% Polyvinyl alcohol aqueous solution together with a ball mill for 24 hours to obtain a leuco dye dispersion. Next, 40 parts of 2,2-bis (p-hydroxyphenyl) propane as an electron-accepting compound was pulverized with a ball mill for 60 hours together with 60 parts of a 2.5% aqueous polyvinyl alcohol solution to obtain a developer dispersion. As a sensitizer, 55 parts of 2-benzyloxynaphthalene was crushed together with 120 parts of a 2.5% aqueous solution of polyvinyl alcohol in a ball mill for 24 hours to obtain a dispersion liquid.

After mixing the above-mentioned three kinds of dispersions, with stirring,
Calcium carbonate 50% dispersion liquid 100 parts, 10% polyvinyl alcohol aqueous solution 170 parts, zinc stearate 40%
25 parts of the dispersion liquid and 140 parts of water were added to prepare a heat-sensitive coating liquid for the second heat-sensitive recording layer.

(C) Preparation of heat-sensitive recording material A base paper having a basis weight of 40 g / m ² was coated with the heat-sensitive coating liquid (A) for the first heat-sensitive recording layer so as to have a solid content of 9 g / m ² . Further, the heat-sensitive coating liquid (B) for the second heat-sensitive recording layer was smeared thereon so that the solid content smeared amount was 9 g / m ² , to prepare a heat-sensitive recording material.

Example 2 3,6-bis (dimethylamino) fluorene-9-spiro-3 '-(6'-dimethylamino) used in Example 1
3,3-bis [2 '-(p-dimethylaminophenyl) -2'-(p-methoxyphenyl) instead of phthalide
Vinyl] A thermosensitive recording material was prepared in the same manner as in Example 1 except that the first thermosensitive recording layer was prepared using -4,5,6,7-tetrachlorophthalide.

Example 3 3,6-bis (dimethylamino) fluorene-9-spiro-3 '-(6'-dimethylamino) used in Example 1
2-chloro-3-methyl-6-p- instead of phthalide
A thermosensitive recording material was prepared in the same manner as in Example 1 except that the first thermosensitive recording layer was prepared using (p-phenylaminophenyl) aminoanilinofluorane.

Example 4 In place of 3-di-n-butylamino-6-methyl-7-anilinofluorane used in Example 1, 3-diethylamino-7-dibenzylaminofluorane was used in the second step. A thermosensitive recording material was prepared in the same manner as in Example 1 except that the thermosensitive recording layer of 1 was prepared.

Comparative Example 1 3,6-bis (dimethylamino) fluorene-9-spiro-3 '-(6'-dimethylamino) used in Example 1
3-di-n-butylamino-6-methyl-7-anilinofluorane was used in place of phthalide to prepare the first thermosensitive recording layer and then 3-di-n-butylamino-6-methyl-
A heat-sensitive recording material was prepared in the same manner as in Example 1 except that the second heat-sensitive recording layer was prepared by using 3-diethylamino-7-dibenzylaminofluorane instead of 7-anilinofluorane.

Test The thermosensitive recording materials obtained in Examples 1 to 4 and Comparative Example 1 were applied with a voltage of 26 by using a G3 facsimile printing tester.
Printing was performed under a low energy condition of V and an energization time of 0.6 msec, and then on another portion under a high energy condition of an applied voltage of 26 V and an energization time of 0.9 msec. The hue of each image obtained and 580 nm in the visible light region and 78 in the near infrared light region
The respective absorbances at 0 nm were measured and summarized in Table 1.

[0036]

[Table 1]

[0037]

As is clear from Table 1, Examples 1 to 4
The heat-sensitive recording material according to the present invention compares the color image obtained by printing with low energy and the color image obtained by printing with high energy, and the absorbances in the visible light region are both the same hue. Although it hardly changes, it can be seen that the absorbance in the near infrared region is low in low energy printing and high in high energy printing. Therefore, it is usually not possible to visually distinguish between the two by printing with low energy and printing the required pattern with high energy, but using an optical reading device that uses near infrared light clearly distinguishes between the two. You can do it. However, in the heat-sensitive recording material according to Comparative Example 1, the color image obtained by printing at low energy and the color image obtained by printing at high energy both have low absorbance in the near infrared region and can be read by an optical reader. It is not possible to distinguish between the two.

Therefore, the heat-sensitive recording material according to the present invention can be easily discriminated when it is forged or altered by recognizing the specific pattern of the near infrared portion formed at the time of printing. Further, the specific pattern of the near infrared region can be changed even one by one, which is more effective in preventing forgery and alteration.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location B41M 5/26 G06K 19/06

Claims (1)

[Claims] 1. A first thermosensitive coloring layer containing, on a support, an electron-accepting compound and an electron-donating compound which forms a dye having absorption in the near infrared region by a reaction with the electron-accepting compound. , An electron-accepting compound, and a second thermosensitive coloring layer containing an electron-donating compound that forms a dye having substantially no absorption in the near infrared region by reaction with the electron-accepting compound, are sequentially laminated. A heat-sensitive recording material characterized in that