JPH0448109B2 - - Google Patents

Description

[Detailed description of the invention]

(A) Technical Field of the Invention The present invention relates to a sublimation transfer type diazo thermal recording material that is capable of multi-tone multicolor expression using a thermal recording method. (B) Prior art and its problems In recent years, with the development of information systems, various output formats are required for hard copies. In particular, there is a strong demand for colorization of hard copies, colorization of displays for soft copies, and responding to the diversity of information. Furthermore, recording devices for obtaining these hard copies are required to have excellent operability, maintainability, and reliability, as well as to be small and low-noise. In response to these demands, thermal recording devices using thermal recording paper are now widely used in facsimile machines, printers, and the like. In other words, as a thermal recording method, a method of obtaining a desired colored recording by bringing a thermal head into contact with a thermal recording paper provided with a recording layer that develops color by causing a physical or chemical change when heated is widespread. but,
This recording method has the disadvantage that the thermal recording paper used is susceptible to color staining due to unavoidable pressure and heat during storage and handling, and it is technically difficult to obtain multicolor recording. There is. Therefore, as an alternative to the above heat-sensitive recording method, for example, as described in Japanese Patent Publication No. 54-10495, paper or resin film is used as a coloring material layer containing a coloring material that is solid or semi-solid at room temperature together with a binder. The color material layer on the base material is brought into contact with the recording sheet, and the binder in the color material layer on the base material is melted and softened by a thermal head, and the color material is mixed with the color material. A method in which adhesive transfer is applied to a recording sheet is generally used, but although multicolor recording is possible with this method, multitone recording is theoretically difficult. As an attempt to overcome these drawbacks and achieve multi-tone, multi-color recording, Japanese Patent Laid-Open No. 55-97984, 55-
As described in Publication No. 101484, there is a method in which the color material layer is composed of a sublimable dye and a high softening point binder. Multi-tone, multi-color recording becomes possible by controlling such that it has the same characteristics. Many such sublimable dyes have been known in the past, for example in the field of sublimation transfer printing of textiles, and some dyes with relatively good coloring properties are found among disperse dyes and basic dyes, but they generally have a high sublimation temperature. , the types of dyes that can be used for thermal recording are quite limited because they require long-term or high-temperature heating for transfer.
Generally, it is limited to some disperse dyes such as nitro, azo, quinoline, anthraquinone, etc. However, when such sublimation dyes are used, dyes with large molecular weights tend to have high sublimation temperatures, making them unsuitable for high-speed thermal recording;
On the other hand, dyes with small molecular weights tend to cause re-sublimation of the dye transferred onto the receiving sheet, which poses a problem in the storage stability of recorded images. (C) Object of the Invention The object of the present invention is to overcome the above-mentioned drawbacks and provide a heat-sensitive recording medium capable of multi-gradation and multi-color expression with high sensitivity and excellent image storage stability. (D) Structure and operation of the invention The present invention provides a transfer sheet having a transfer layer on a substrate containing a sublimable coupler and a high softening point binder as main components, and a diazonium salt that reacts with the sublimable coupler to form a dye. The present invention also relates to a sublimation transfer type diazo thermal recording material comprising a receiving sheet having a receiving layer containing an organic basic compound as a main component. As the sublimable coupler used in the present invention, it is preferable to use a relatively low molecular weight heat sublimable coupler with a sublimation temperature of 70° C. to 200° C. Specific examples include the following compounds. (1) Phenol derivatives Phenol Ortho-phenylphenol Pyrocatechol Resorcin Phloroglycine Pyrogallol Ortho-aminophenol Meta-aminophenol Para-aminophenol Diethylaminophenol 3,3',5-trihydroxydiphenyl 3,3',5,5'-tetraside Roxidiphenyl diresorcin sulfide 4-bromoresorcin 4-tertiary octylresorcin 2-methylresorcin salicylic acid salicyl alcohol 2,5-dihydroxybenzoic acid (2) Oxynaphthalene derivative 2,3-dihydroxynaphthalene β-naphthol α-naphthol 1,6-dihydroxynaphthalene 2-hydroxy-3-naphthoic acid-N-β-hydroxyethyl-amide 2-hydroxy-3-naphthoic acid-N,N-bisβ-hydroxyethylamide 5-(paranitro)-benzamide- 1-naphthol 1-naphthol-3-(N-β-hydroxyethyl)-sulfone-amide 2-hydroxy-3-propylmorpholinonaphthoic acid 2-hydroxy-3-naphtho-O-toluidide 2-hydroxy-3-naphthoic acid Morpholinopropylamide 2-hydroxy-3-naphthoic acid-4'-chloroanilide (3) Compound containing active methylene group 1-phenyl-3-methyl-pyrazolone (5) Acetoacetic acid anilide acetoacetic acid-O- Chloranilide acetoacetate cyclohexylamide acetoacetate benzylamide cyanoacetanilide cyanoacetomorpholin The substrate of the transfer sheet that can be used in the present invention must have high thermal conductivity and high heat resistance.
In addition, high mechanical strength is also an important condition for repeated use, and any material that satisfies these conditions can be used, regardless of whether it is paper or synthetic resin film. Particularly suitable papers include glassine paper, condenser paper, thin paper, etc., and synthetic resin films such as polyethylene terephthalate, polyvinyl fluoride, polytetrafluoroethylene, etc.
Examples include films of polyvinylidene chloride, polyvinyl chloride, high density polyolefins such as polyethylene and polypropylene, certain cellulose acetates, polycarbonates, polyimides, and the like. In addition, heat-resistant materials such as silicone resin, epoxy resin, melamine resin, phenol resin, fluororesin, polyimide resin, nitrocellulose, etc. are applied to the surface that contacts the thermal head on the opposite side of the transfer layer applied to these papers or films. It is also possible to provide a protective film. Further, as a high softening point binder for adhering the sublimable coupler to the substrate to form a transfer layer on the substrate, natural or synthetic polymer compounds can be used, and specific examples include cornstarch, gum arabic,
Glue, gelatin, casein, methylcellulose, ethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, polyacrylamide, starch such as carboxymethyl starch, dialdehyde starch or its modified products and derivatives, polyvinyl alcohol or its modified products and derivatives, polyvinylpyrrolidone, isobutylene- Maleic anhydride copolymer, polyacrylate, styrene-maleic anhydride copolymer, polyvinyl chloride, polyvinylidene chloride, polystyrene,
Styrene styrene butadiene rubber (=SBR), polyester, polycarbonate, polysulfon, nitrocellulose, acetyl cellulose, methacrylate butadiene rubber (=MBR), nitrile butadiene rubber (=NBR), polymethyl methacrylate, polypropylene, polyacrylonitrile, acrylic ester, etc. These can be dissolved or dispersed in water, emulsified and used as an emulsion, or dissolved in an organic solvent. Additionally, if necessary, a curing agent can be used in combination with these binders to impart heat resistance to prevent the transfer layer from fusing to the receiving layer during heating recording, thereby preventing a decrease in the clarity and resolution of the recorded image. It is possible. Specific examples of curing agents include silane coupling agents, zirconium chelating agents, Mg, Ca, Zn,
Conventionally known hardening agents such as polyvalent metal compounds such as Pb, melamine-formalin resin, urea-formalin resin, etc. can be used. In order to obtain good clarity and resolution of recorded images, it is desirable that the thermal softening temperature of the transfer layer is higher than the sublimation temperature of the sublimable coupler, and it is particularly preferable that the softening point is 100° C. or higher. Another method for achieving this purpose is to use a resin that cures and crosslinks with radiation such as ultraviolet rays or electron beams as a binder for the transfer layer. Such resins are composed of monomers, prepolymers, or polymers, or mixtures thereof, having at least one polymerizable unsaturated double bond in their structure, and optionally contain a photopolymerization initiator. These crosslinkable resins themselves are known. Furthermore, in addition to the sublimable coupler and binder, non-sublimable particles may be added to the transfer layer of the present invention, if necessary. The material constituting the non-sublimable particles is selected from metals, metal oxides, metal sulfides, graphite, carbon black, minerals, inorganic salts, and organic pigments. Examples of highly effective methods are listed below. Metals: aluminum, silicon, germanium, tin, copper, zinc, silver, iron, cobalt, nickel,
Chromium and alloys mainly composed of chromium. Metal oxides: alumina, beryllium oxide, magnesium oxide, zinc oxide, tin oxide, titanium oxide, silicon oxide, iron oxide, cobalt oxide, nickel oxide, manganese oxide, tantalum oxide, vanadium oxide, tungsten oxide. Metal sulfides: copper sulfide, zinc sulfide, tin sulfide, molybdenum sulfide. Minerals: lime minerals, barium minerals, zirconium minerals, titanium minerals, phosphorous minerals, aluminum minerals (waxite, kaolin, clay), silicon minerals (mica, talc, zeolite, diatomaceous earth). Inorganic salts: carbonates or sulfates of alkaline earth metal elements (magnesium carbonate, calcium carbonate, strontium carbonate, barium carbonate, magnesium sulfate, calcium sulfate, strontium sulfate,
Barium sulfate) These non-sublimable particles eliminate background fog during storage due to direct contact between the sublimable coupler during transfer and the diazonium salt in the receiving layer, and also eliminate heat applied from the thermal head through the substrate by non-sublimating. It conducts smoothly to the sublimable coupler near the sexual particle itself, and helps the coupler to sublimate uniformly. The transfer layer of the present invention can be prepared by using a blade coater, an air knife coater, etc. by adding other solvents, pigments, additives, etc. as the main ingredients, and if necessary, the above-mentioned components.
It can be provided on the base of the transfer sheet using a known coating or printing means such as a roll coater, curtain coater, or gravure coater. On the other hand, as the diazonium salt which is the main component of the receptor layer, any compound used in conventionally known diazo type copying materials can be used. For example, 4-N,N-dimethylaminobenzenediazonium Chloride, 3-chlor-4-
N,N-dimethylaminobenzenediazonium chloride, 4-N,N-diethylaminobenzenediazonium chloride, 2,5-diethoxy-4-
N,N-diethylaminodiazonium chloride,
4-N-ethyl-N-hydroxyethylaminobenzenediazonium chloride, 4-N,N-diethoxyaminobenzenediazonium chloride, 4
-phenylaminobenzenediazonium chloride, 4-N-(P-methoxyphenyl)-aminobenzenediazonium chloride, 4-morpholinobenzenediazonium chloride, 2,5-diethoxy-4-morpholinobenzenediazonium chloride, 4 -Oxazolidinobenzenediazonium chloride, 3-methyl-4-piperidinobenzenediazonium chloride, 4-ethylmercapto-2,5-diethoxybenzenediazonium chloride, 4-tolylmercapto-2,5-diethoxybenzenediazonium chloride , 4-benzylmercapto-2,5-dimethoxybenzenediazonium chloride, etc., but these include zinc chloride salt and other anion components such as tetrafluoroborate, and water-insoluble diazonium salts such as teleraphenylborate. It can also be added after being dispersed in the form of fine particles. These diazonium salts react with couplers to produce yellow dyes, generally with phenolic derivatives or coupler compounds containing active methylene groups, and magenta dyes by reacting with certain couplers such as pyrazolone derivatives or polyphenolic couplers. ,
Further, it reacts with certain oxynaphthalene derivatives to form a cyan dye, but it is possible to form a dye of a desired hue by combining one or several types of diazonium salts. Therefore, as in the present invention, by using a sublimable coupler whose amount of sublimation changes depending on the amount of thermal energy provided by the thermal head, yellow, magenta, and cyan dyes are produced by reacting with the diazonium salt in the receiving layer. By sequentially sublimation-transferring couplers capable of forming , onto the receiving layer, it becomes possible to express multi-tone and multi-color using a heat-sensitive recording method. Moreover, since the azo dye produced by the reaction of the sublimable coupler with the diazonium salt naturally has a larger molecular weight than the molecular weight of the sublimable coupler itself, it is less likely to be re-sublimated compared to the case where a general sublimable dye is used. A stable recorded image can be formed, and a sublimable coupler having a relatively low molecular weight can be selected, so that multi-tone, multi-color recording with high color development sensitivity and excellent image storage stability is possible. The receiving sheet on which a recorded image has been formed can be stored as is, but if necessary, the entire surface may be exposed to light to photodecompose the diazonium salt remaining in the receiving layer. Further, as the organic basic compound used in the present invention, as long as it is a compound having basicity to the extent that it promotes the coupling reaction between the coupler and the diazonium salt, for example, thiazole, pyrrole, pyrazole,
Pyrimidine, piperidine, indole, imidazole, triazole, morpholine, guanidine,
Although any generally known organic basic compounds such as pyridine, hydrazine, and amines can be used, particularly preferred organic basic compounds include fine particle dispersions of hydrophobic guanidine derivatives of the following general formulas () and (). By doing so, a sublimation transfer type diazo thermosensitive recording material having high sensitivity and excellent storage stability can be obtained. General formula () General formula () [In the formula, R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are hydrogen, alkyl having 18 or less carbon atoms, cyclic alkyl, aryl, aralkyl, amino, alkylamino, acylamino, carbamoylamino, or a heterocyclic residue. and R ₆ is lower alkylene, phenylene, naphthylene or

[Formula] (In the formula, X is lower alkylene, SO ₂ , S ₂ , S, O, -NH-
or a single bond), and the aryl group in the formula includes those having a substituent selected from lower alkyl, alkoxy, nitro, acylamino, alkylamino groups, and halogen. ] Typical specific examples are shown in Table 1, but the invention is not limited thereto. In the table

[Creating a reception sheet]

A coating solution for the receptor layer was prepared with the following formulation, and coated onto a support so that the coating amount after drying was 3.0 g/m ² , and dried to prepare a receptor sheet. The unit is parts by weight. Water 50 Citric acid 1 2,5-diethoxy-4-dimethylaminobenzenediazonium tetrafluoroborate 2 Calcined kaolin 10 Part A 60 10% polyvinyl alcohol 100 Part A was obtained by grinding the following composition in a ball mill for 48 hours. It was prepared using A liquid 50 (Compound (7) in Table 1) Stearamide 50 10% methyl cellulose 50 Water 150 [Preparation of transfer sheet] Example 1 A coating liquid for a transfer layer was prepared with the following formulation, and a thickness of 10μ was prepared.
The amount of coating after drying on the condenser paper is 1.5g/
A transfer sheet was prepared by applying the coating to a total area of 2 m ² and drying it. The unit is parts by weight. Ethylcellulose 10 Resorcinol 5 Non-sublimable particles (alumina) 5 Ethanol 50 A mixture of the above composition was prepared using glass beads.
Treated with paint conditioner for about 30 minutes. Example 2 A transfer sheet was prepared in the same manner as in Example 1 except that β-naphthol was used instead of resorcinol. Example 3 A transfer sheet was prepared in the same manner as in Example 1 except that ortho-phenylphenol was used instead of resorcinol. The transfer sheet and receptor sheet created as described above were placed one on top of the other, and the transfer layer and receptor layer were placed relative to each other, and heated for 3 seconds with a thermal block (5 cm x 5 cm) at 120°C from the opposite side of the substrate to the transfer layer. A colored image was obtained on the receiving sheet. Example 1 formed a red image with a color density of 1.2, Example 2 formed a blue image with a color density of 1.1, and Example 3 formed a yellow image with a color density of 1.1. (The color density was measured using a Macbeth densitometer RD-514) In addition, for each of Examples 1 to 3, the amount of heating energy was changed by changing the pulse width in stages using a facsimile, and the results corresponded to the amount of heating energy. A transferred image with a certain density was recorded on the receiving layer. Comparative Examples 1 to 3 Receiving sheets of Comparative Examples 1 to 3 were prepared in the same manner as in Examples, except that the hydrophobic guanidine derivative of liquid A used in Examples 1 to 3 was replaced with amine stearate. The transfer sheets corresponded to those used in Examples 1 to 3, respectively, and were used in Comparative Examples 1 to 3.
Each transfer sheet and receiving sheet were overlapped and heated to develop color in the same manner as in the example. Comparative examples 1 to 3
The color density obtained is 0.55 (reddish) and 0.55 (redish), respectively.
0.60 (blue color) and 0.45 (yellow color), which were lower values compared to the transfer sheet using the hydrophobic guanidine derivative of Example. (F) Effects of the Invention By using the sublimation transfer type diazo thermal recording material of the present invention, it is possible to express multi-tone multi-colors using a thermal recording method, and the transfer sheet maintains almost the same color density even after multiple uses. A recorded image could be generated on the receiving layer without any deterioration.

Claims (1)

[Scope of Claims] 1. A transfer sheet having a transfer layer mainly composed of a sublimable coupler and a high softening point binder on a substrate, a diazonium salt that reacts with the sublimable coupler to form a dye, and the following general A sublimation transfer type diazo thermosensitive recording material comprising a receiving sheet having a receiving layer containing a hydrophobic guanidine derivative represented by the formula () or () as a main component. General formula () General formula () [In the formula, R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are hydrogen, alkyl having 18 or less carbon atoms, cyclic alkyl, aryl,
Represents aralkyl, amino, alkylamino, acylamino, carbamoylamino, heterocyclic residue,
R ₆ represents lower alkylene, phenylene, naphthylene, or [Formula] (wherein X represents lower alkylene, SO ₂ , S ₂ , S, O, -NH-, or a single bond), and the aryl group in the formula is lower Also included are those having substituents selected from alkyl, alkoxy, nitro, acylamino, alkylamino groups and halogen. 2. The sublimation transfer type diazo thermal recording material according to claim 1, wherein the high softening point binder has a softening point of 100° C. or higher. 3. The sublimation transfer type diazo thermosensitive recording material according to claim 2, wherein the organic basic compound is contained in the receiving layer as a fine particle dispersion with a particle size of 0.1 to 10 μm.