Waxy crayon or ink-like diazotype developer composition comprising heat transferrable azo coupler and transfer promotor

Abstract

A process for diazo-type multicolor reproduction according to which it is possible to obtain multi-colored copies in which portions corresponding to predetermined portions of an original area colored selectively in different hues without substantial mingling of colors, by conducting the heat transfer at relatively low temperatures (for instance, at 60.degree. - 80.degree.C.), and a color former to be used in such process, which comprises a thermosublimative coupler and a thermosublimative, organic, solid transfer promotor having no coupling property in itself.

Parent Case Text

This is a continuation of application Ser. No. 139,442, filed May 3, 1971, now abandoned.

Description

This invention relates to a process for diazo-type multi-color reproduction and to a color former to be used in such process. More particularly, this invention relates to a process for the diazo-type multicolor reproduction according to which it is possible to obtain multi-colored copies in which portions corresponding to predetermined portions of an original are colored selectively in different hues without substantial mingling of colors, by conducting the heat transfer at relatively low temperatures (for instance, at 60.degree. - 80.degree.C.), and to a color former to be used in such process.

A process for the diazo-type multi-color reproduction has been previously proposed based on the discovery that predetermined portions of an original can be reproduced into different hues regardless of difference or similarlity of the light transmission in the original, by conducting the steps of (A) exposing to light a diazo-type photosensitive material containing at least one diazonium salt (which will be referred to as "diazonium salt (c)") and (B) heating a layer of at least one thermovolatile or thermosublimative coupler (which will be referred to as "coupler (a)") disposed in face-to-face contact with such diazo-type photosensitive material at a portion corresponding to a predetermined portion of the original to be colored in a different hue, the steps being carried out coincidentally or in an order of (A) to (B) or (B) to (A), and then developing the light-exposed photosensitive material in the presence of a coupler having a lower coupling rate under developing conditions (which will be referred as "coupler (b)") than the thermovolatile or thermosublimative coupler (a). In this diazo-type multicolor reproduction process, a thermovolatile or thermosublimative coupler is combined with the back face of an original at one or more portions predetermined to be colored in a different hue. The thermovolatile coupler in the form of, for instance, an ink-like or waxy coloring composition is combined with the back face of the original by coating or transferring. Most of thermovolatile and thermosublimative couplers have relatively high volatilizing or sublimating temperatures, and therefore, the heat transfer must be conducted at temperatures exceeding 100.degree.C. The high heat transfer temperature results in the following disadvantages. Namely, the life of a copying machine is extremely shortened and its structure is inevitably complicated. Further, the high heat transfer temperature causes various operational difficulties. Still further, when multi-colored copies are obtained by employing two or more thermovolatile or thermosublimative couplers differing in their volatilizing or sublimating temperature, it is difficult to determine the heat transfer temperature. More specifically, when the heat transfer temperature is determined depending on a coupler having a lower volatilizing or sublimating temperature, the amount of the coupler having a higher volatilizing or sublimating temperature transferred is very low and copies of a high color contrast cannot be obtained, whereas if the heat transfer temperature is determined depending on the coupler of a higher volatilizing or sublimating temperature, great excess of the coupler of a lower volatilizing or sublimating temperature is transferred by one transfer treatment, with the result that the transfer layer is consumed by conducting the heat transfer only several times and the number of copies is extremely lowered.

Further research on the above-mentioned diazo-type multicolor reproduction process has been conducted with a view to overcoming these defects, and it has now been found that when a certain solid substance having no coupling property in itself is incorporated into the thermovolatile or thermosublimative coupler (a), the transfer of the coupler (a) to a diazo-type photosensitive material can be effected at a relatively low temperature very easily and even if two or more couplers (a) are used, heat transfer temperatures and the amounts of the couplers transferred can be almost approximated. Based on this finding, the present invention has been developed.

Accordingly, the primary object of this invention is to provide a diazo-type multicolor reproduction process according to which the heat transfer of one or more couplers to a diazo-type photosensitive material can be effected at a relatively low temperature, and to provide a color former for use in conducting such process.

Another object of this invention is to provide a diazo-type multicolor reproduction process according to which two or more couplers to be combined with a diazo-type photosensitive material can be heat-transferred with almost equal amounts at approximating temperatures, whereby many copies can be obtained from one original with the heat transfer layer formed thereon, while conducting the heat transfer at relatively low temperatures, and to provide a color former to be used in such process.

In accordance with this invention, a color former for use in the diazo-type multicolor reproduction is provided, which comprises a thermovolatile or thermosublimative coupler, and a thermosublimative, organic, solid transfer promotor having no coupling property in itself. The above objects of this invention can be attained by the use of such color former.

In accordance with this invention, an improvement of the above-mentioned diazo-type multicolor reproduction process previously proposed, is provided wherein a color former comprising a thermovolatile or thermosublimative coupler, and a thermosublimative, organic, solid transfer promotor having no coupling property in itself is used as the coupler (a).

In this invention it is essential that the thermosublimative, organic, solid, transfer promoter should not possess any coupling property in itself. As such transfer promotor any organic compound that exhibits a high sublimating property at temperatures exceeding room temperature, especially at temperatures exceeding 60.degree.C. and has a melting point above 60.degree.C., preferably above 100.degree.C. can be used

The transfer promoter may be chosen from naphthalene, naphthalene derivatives, terpene compounds, halogenated benzenes and other organic solid sublimative compounds. Typical examples of such transfer promotor are as follows:

Naphthalene

d-Camphor

Menthol

Camphene

Benzoic acid

Maleic anhydride

Phthalic anhydride

Oxalic acid

Fromic acid

Anthranilic acid

Ethylboric acid

Phenylhydrazine hydrochloride

p-Hydroxyphenyl acetic acid

Atropine

2-Aminoquinoline

.alpha.-Chloroacrylic acid

o-Chlorobenzoic acid

p-Dichlorobenzene

Chlorofumaric acid

Diacetone-D-glucose

1,4 Cyclohexadione

2,6-Dichlorobenzoic acid

Di-.alpha.-naphthyl ketone

N,N-diphenyl acetamide

2,4-Dimethyl-3-furan-carboxylic acid

Dimethylphosphinic acid

Cinnamylideneacetic acid

Tartronic acid

Thiourethane

2,3,4,5-Tetramethylpyrrol

Triiodobenzene

.alpha.-Naphthyl ketone

1,8-Naphthylene diamine

Nitrobenzonitrile

Hydrochelidonic acid

Pyridine carboxylic acid

Pyrene

Phenanthrene

Phenylpropiolic acid

3-Furancarboxylic acid

o-Benzylbenzoic acid

Bornane

Meconine

Mesitylenic acid

5-Methyl-2-furancarboxylic acid

Lapachol

It is essential that among the thermovolatile or thermosublimative coupler (a) to be used in the color former of this invention, a coupler (b) and a diazonium salt (c) the following relations should be established in conducting the multicolor reproduction according to this invention:

I. thermovolatile or thermosublimative coupler (a) has a higher coupling rate under developing conditions than coupler (b).

Ii. dyestuff (b)-(c), dyestuff (a)-(c), dyestuff (a')-(c) . . . .. formed at the development have hues different from one another.

Any coupler that can be volatilized or sublimated under heating conditions may be used as the thermovolatile or thermosublimative coupler (a) in this invention. As such coupler (a) phenol derivatives, hydroxynaphthalene derivatives, aniline derivatives and active methylene group-containing compounds may be mentioned. In view of facilitation of the heat transfer operation it is preferred that these derivatives do not contain soluble groups such as a sulfonic acid group.

Examples of these derivatives usable as coupler (a) are as follows:

Phenol Derivatives

Phenol

Pyrocatechol

Resorcin

Phloroglucin

o-Hydroxybenzalcohol

Resorcin monoglycol ether

Resorcin diglycol ether

Hydrotoluquinone

Pyrogallol

5-Hydroxy-isophthalic acid

Pyrogallol-4-carboxylic acid

Vanillin

Isovanillic acid

Vanillic acid

2-Hydroxy-terephthalic acid

2-Hydroxy-p-toluylic acid

3-Hydroxy-p-toluylic acid

5-Hydroxy-o-toluylic acid

6-Hydroxy-m-toluylic acid

Para-Hydroxyphenylacetic acid

Para-hydroxybenzaldehyde

Ortho-hydroxybenzoic acid

Ortho-hydroxybenzyl alcohol

4,4-Dihydroxybiphenol

3,5-Dichloro-salicylic acid

5-Chloro-2-nitrophenol

2,5-Dihydroxyacetophenone

2,5-Dinitrophenol

2,4-dinitrophenol

2,4-Dinitroresorcin

4,6-Dibromo-2-nitrophenol

2,5-Dimethyl hydroquinone

Aniline Derivatives

Meta-aminobenzoic acid

Dimethyl-meta-amino-phenol

2-Amino-p-cresol

Ortho-aminophenol

Meta-aminophenol

Para-aminophenol

Para-chloroaniline

3,4-Diaminotoluene

Active Methylene Group-Containing Compounds

1-Phenyl-3-methylpyrazolone (5)

1-Phenyl-3-carboxypyrazolone

Acetoacetic acid anilide

Acetoacetic-o-chloroanilide

Hydroxynaphthalene Derivatives

2,3-Dihydroxynaphthalene

.beta.-Naphthol

.alpha.-Naphthol

1,6-Dihydroxynaphthalene

8-Amino-2-naphthol

2,6-Dihydroxynaphthalene

2,7 Dihydroxynaphthalene

5-Hydroxy-1-naphthonic acid

2,2'-dihydroxy-1,1'-binaphthyl

4,4'-dihydroxy-1,1'-binaphthyl

3-Carboxy-2-naphthol

As coupler (b) to be used in combination with the thermovolatile or thermosublimative couple (a) for conducting the multicolor reproduction with use of the color former of this invention, any coupler that has a lower coupling rate with the diazonium salt (c) under the developing conditions than the rate of coupling of the thermovolatile or thermosublimative coupler (a) contained in the color former with the diazonium salt (c) can be used. When a plurality of thermovolatile or thermosublimative couplers (a) are used, the coupling rate of the coupler (b) should be lower than that of any of couplers (a). Selection of couplers (a) and (b) meeting the above requirement may be easily performed by those skilled in the art based on simple experiments.

Couplers having a relatively lower coupling rate may be selected among couplers recited above with respect to the thermovolatile or thermosublimative couplers (a) and be used as the coupler (b). In addition, the following may be used as coupler b) in this invention.

Phenol Derivatives

2,5,6-Trimethylphenol

2-Hydroxymethylphenol

.beta.-(2-hydroxyphenyl)-propionic acid

2-(.epsilon.-Phenylaminomethyl)-phenol

.beta.-(4-Methyl-2-hydroxyphenyl)-glutaric acid

2,5-Dimethyl-6-(N-dimethylaminomethyl)-phenol

1,3-Dimethyl ether of pyrogallol

.alpha.-Resorcylic acid ethanolamine

.beta.-Resorcylic acid

N-Lauryl-p-aminophenol

N-Acyl-m-aminophenol

Meta-hydroxy-acetoanilide

Ortho-N-hydroxyphenyl-monoguanidine

Para-N-hydroxyphenyl-biguanidine

2,5-Dimethyl-4-morpholinomethyl phenol

2-Methyl-5-isopropyl-morpholinomethyl phenol

4-Morpholinomethylresorcinol monomethyl ether

3,3',5-Trihydroxydiphenyl

3,3',5,5'-Tetrahydroxydiphenyl

2,2',4,4'-Tetrahydroxydiphenyl

2,4,4'-Trihydroxydiphenyl-2'-sulfonic acid

2,4,6,3',5'-Pentahydroxydiphenyl

2,2',4,4'-Tetrahydroxydiphenyl sulfide

Naphthols

2,3-Dihydroxynaphthalene-6-sulfonic acid

2-Naphthol-3,6-disulfonic acid

2,7-Dihydroxynaphthalene-3-sulfonic acid

2,8-Dihydroxynaphthalene-6-sulfonic acid

1,8-Dihydroxynaphthalene-8-sulfonic acid

1,8-Aminonaphthol-5-sulfonic acid

2,7-Dihydroxynaphthalene-3,6-disulfonic acid

1,8-Benzoylaminonaphthol-2-sulfonic acid

1,8-Dihydroxynaphthalene-6-sulfonic acid

2-Hydroxy-3-naphthionic-N-.beta.-hydroxyethyl amide

.beta.-Hydroxynaphthionic acid aminoethylamine

2-Hydroxy-3-naphthionic-N,N-bis-.beta.-hydroxy ether amide

8-Hydroxy-2-naphthionic-hydroxyethyl amide

1-(N-Carboethoxymethylamino)-8-naphthol-4-sulfonic acid

5-(Para-nitro)-benzamido-1-naphthol

1-Hydroxynaphthyl-7-phenyl-guanidine

2-Hydroxynaphthyl-8-biguanidine

1-Naphthol-3-(N-.beta.-hydroxyethyl)-sulfonic amide

1-Naphthol-3-(N-o-methoxyphenyl)-sulfonic amide

Bis-(5-hydroxy-7-sulfo-naphthyl(2)!-amine

N,N-Bis?1-hydroxy-3-sulfo-naphthyl(6)!-thiourea

Active Methylene Group-Containing Compounds

Acetoacetic acid cyclohexylamide

Acetoacetic acid benzylamide

Cyanoacetoanilide

Cyanoacetomorpholine

Heterocyclic Compounds

1-(3'-Sulfoamide)-phenyl-3-methylpyrazolene-5

1-(4'-Carboxy-ethylphenyl)-3-dodecyl-pyrazolone-5

8-Hydroxy-1,2-naphthylimidazole

2-Methyl-4-hydroxybenzimidazole

7-Methyl-4-hydroxybenzothiazole

1,7-Dimethyl-4-hydroxy-benzotriazole

3-Hydroxythiophene-5-carboxylic acid

1-3-4-Cyclopentatrione

In conducting the diazo-type multicolor reproduction with use of the color former comprising the above-mentioned thermovolatile or thermosublimative coupler (a) and thermosublimative, organic, solid transfer promotor in accordance with this invention, at first an original for multicolor development is formed by applying at least one transparent or semi-transparent layer of a mixture of a thermovolatile or thermosublimative coupler (a) and a thermosublimative, organic, solid transfer promotor onto the back surface of a transparent or semi-transparent original to be copied, in one or more predetermined portions thereof.

The so formed original for multicolor development is over-lapped on the diazo-type photosensitive material containing at least one diazonium salt in a manner such that the layer of coupler (a) will confront the photosensitive surface of the photosensitive material, and the light-exposure and heating are effected coincidentally or successively in this order or the reverse order. Thus, the thermovolatile or thermosublimative coupler (a) is heat-transferred to the predetermined portion of the surface of the photosensitive material together with the transfer promotor at a relatively low temperature (60.degree. - 100.degree.C.), and the light resolution of the diazonium salt (c) in the photosensitive material occurs depending on the light transmission of the original. When the so exposed photosensitive material is developed by a method known per se, at the predetermined portion to which the coupler (a) has been heat-transferred, the diazonium salt (c) at the non-exposed area reacts selectively and preferentially with the coupler (a) to form a dyestuff (c) - (a) and at other portions the diazonium salt (c) in the non-exposed area reacts with coupler (b) to form a dyestuff (c) - (b). As a result a multicolored reproductive copy in which the predetermined portion is colored in a hue different from that of the other portion is obtained.

The above-mentioned original for multicolor development may be prepared, for instance, by a method comprising applying a coating composition containing the above-mentioned color former comprising the thermovolatile or thermosublimative coupler (a) and the transfer promotor onto the back surface of a portion predetermined to have a different hue, of a transparent or semi-transparent original to be copied, or by a method comprising coating or impregnating a transparent or semi-transparent substrate with a coating composition comprising the color former of this invention and combining the resulting sheet for heat-transferring the coupler, with the back surface of the specific portion of the original predetermined to have a different hue in a manner such that the layer for heat-transferring the coupler will confront the photosensitive material.

The color former of this invention for use in the diazo-type multicolor reproduction can be easily prepared by dispersing a thermovolatile or thermosublimative coupler (a) and a thermosublimative, organic, solid transfer promotor in a liquid, semi-solid or solid dispersion medium.

Such color former composition will now be described by referring to some embodiments.

1. Ink-like color former composition:

Coupler (a) 5.0 - 40.0 % Thermosublimative transfer promotor 5.0 - 30.0 % Coloring material 0 - 3.0 % Binder 0 - 5.0 % Dispersion assistant 0 - 2.0 % Dispersion medium balance

As the dispersion medium aliphatic alcohols such as methanol, ethanol, propanol, isopropanol, isobutyl alcohol and dimethyl formamide; aromatic solvents such as benzene, toluene, xylene; esters; and neutral liquids having OH groups and boiling points of 100.degree. - 250.degree.C. such as water, high boiling point alcohols, e.g., n-hexyl alcohol, n-heptyl alcohol, 3-heptanol, 4-heptanol, and octanol, and glycols, e.g., glycerine, ethylene glycol, propylene glycol, polyethylene glycol, 1,3-butanediol, 1,4-butanediol and 2,3-butanediol may be used. These liquid substances may be used singly or in combination.

It is possible to incorporate a coloring material so as to confirm the formation of a film of the color former composition, or to use a binder for the purpose of obtaining a good fixation of the coupler (a).

The composition of the above recipe is applied to the back surface of an original in a portion predetermined to have a different hue by means of a brush, an installed felt pen, a ball pen, a coating roller, a sprayer or a printing machine.

2. Waxy color former composition:

Coupler (a) 0.5 - 40.0 % Thermosublimative transfer promotor 0.5 - 25 % Wax 80 - 5 % Oil 10 - 30 % Coloring material 0 - 10 %

The composition of the above recipe is shaped to have a crayon stick-like form or a chalk-like form, and the back surface of a portion of an original predetermined to have a different hue is painted therewith. It is also possible to form a pressure-sensitive transfer sheet by melting the above composition or dissolving it in a suitable solvent and coating the melt or solution on a substrate such as paper and plastic film. The so formed pressure-sensitive transfer sheet is overlapped on the back surface of an original sheet, and then pressing is effected thereon by means of a typewriter or other writing means to form a heat-transferable layer comprising the coupler (a) and transfer promotor on the back surface of an image predetermined to have a different hue.

3. Coupler-transferring sheet for treating the back surface of an original:

The ink-like color former composition for treating the back surface of an original, which was described in (1), or a composition obtained by incorporating a binder or an extender into such ink-like composition is coated on a transparent or semi-transparent sheet such as paper, plastic film or non-woven fabric. The so formed sheet for heat-transferring the coupler is cut into a desired size, if necessary, and then applied to the back surface of a portion of an original predetermined to have a different hue. It is possible to form a pressure-sensitive adhesive layer on the back surface of the coupler-transferring layer for preventing it from exfoliating from the original.

The so prepared original for multicolor development may be generally used 5 to 100 times repeatedly for the multicolor development, though the applicable frequency of the repeated use varies depending on the amount of coupler (a) coated, the coating method, the heating method and the developing method. Of course, when the heat-transferability of coupler (a) in the layer for heat-transferring the coupler is lowered, it is sufficient to newly supply an additional layer for heat-transferring the coupler.

The above-mentioned color former composition in use for the multicolor reproduction is applied to the back surface of a predetermined portion of an original to be copied, and is overlapped on a photosensitive material in a manner such that the heat transfer layer containing the coupler (a) and thermosublimative transfer promotor will be in face-to-face contact with the photosensitive surface of the photosensitive material. Then, the assembly is exposed to light and heated.

The photosensitive material containing a diazonium compound (c) may be prepared by coating a sensitizing composition comprising the diazonium compound (c) and optionally the coupler (b) according to need depending on the developing method, on a substrate such as paper, plastic film, non-woven fabric and metal foil. The preparation of such photosensitive material will now be described by referring to same examples.

A. Sensitizing composition for dry development:

Azo coupling component (b) 0.2 - 5.0 % Diazonium compound (c) 0.2 - 5.0 % Organic acid 0.1 - 5.0 % Coloring matter 0.001 - 0.025 Development promotor 1.0 - 10.0 % Extender 0 - 2.5 % Solvent balance

The sensitizing composition of the above recipe is coated on a substrate such as paper and plastic film and dried to form a photosensitive sheet.

B. Two-component-type sensitizing composition for wet development:

Azo coupling component (b) 0.2 - 5.0 % Diazonium compound (c) 0.2 - 5.0 % Organic acid 0.1 - 5.0 % Extender 0 - 2.5 % Stabilizer 0 - 5.0 % Coloring matter 0.001 - 0.025 % Solvent balance

The sensitizing composition of the above recipe is coated on a substrate such as paper and plastic film to form a photosensitive sheet.

C. One-component-type sensitizing composition for wet development:

Diazonium compound (c) 0.2 - 5.0 % Organic acid 0.1 - 5.0 % Extender 9 - 2.5 % Coloring matter 0.001 - 0.025 % Solvent balance

The sensitizing composition of the above recipe is coated on a substrate such as paper, and dried to form a photosensitive sheet.

As the diazonium compound (c) any diazonium compound that can couple with the above-mentioned couplers (a) and (b) under ordinary developing conditions can be used. Typical examples of such diazo component (c) are mentioned below:

Para-phenylene-diamine-N,N-substituted compounds of the following general formula: ##EQU1## wherein X stands for an anion, R' and R" each are aliphatic groups, and Z and Y denote groups which can be introduced into the benzene nucleus.

Specific examples of the compounds of this type are as follows:

4-Diazo-N,N-dimethyl aniline (referred to simply as "MA salt")

4-Diazo-N,N-diethyl aniline (referred to simply as "EA salt")

4-Diazo-N-ethyl-N-.beta.-hydroxyethyl aniline (referred to simply as "EH salt")

4-Diazo-N,N-bis-.beta.-hydroxyethyl aniline

4-Diazo-N-methyl-N-.beta.-hydroxyethyl aniline

4-Diazo-N-ethyl-N-.beta.hydroxypropyl aniline

Other diazonium salts of p-phenylene diamines N,N-substituted with alkyl or hydroxy-alkyl groups:

4-Diazo-N-ethyl-N-(.beta.-diethylamino)-ethyl aniline

4-Diazo-2-chloro-N,N-diethyl aniline

4-Diazo-2-methyl-N,N-diethyl aniline

4-Diazo-2-iodo-N,N-diethyl aniline

4-Diazo-2-trifluoromethyl-N,N-diethyl aniline

4-Diazo-N-ethyl-N-benzyl aniline

4-Diazo-N-methyl-N-benzyl aniline (referred to simply as "methyl benzyl")

Aminohydroquinone ether-type compounds of the following general formula: ##EQU2## wherein R, R' and R" are alkyl or aryl groups and X stands for an anion.

Specific examples of the compounds of the above type are as follows:

4-Diazo-2,5-dibutoxy-N,N-diethyl aniline

4-Diazo-2,5-diethoxy-N-benzoyl aniline (referred to simply as "BB salt")

4-Diazo-2,5-diethoxy-N-ethyl-N-benzoyl aniline

4-Diazo-2,5-dibenzyloxy-N-benzoyl aniline

4-Diazo-2-chloro-5-methoxy-N-benzoyl aniline

4-Diazo-2,5-diethoxy-N-benzoyl-methyl aniline

4-Diazo-2,5-diethoxy-N-benzoyloxy-methyl aniline

Other 4-diazo-2,5-dioxyalkyl (or dioxyaryl)-N-alkyl (or aryl) compounds and derivatives thereof

Aminodiphenyl compounds, aminodiphenyl amine compounds and their analogues of the following general formulas:

X.sup.-.sup.+ N.sub.2 --R--A--R' and .lambda..sup.-.sup.+ N.sub.2 --R--A--R' .sup.+.sup.-.lambda.

wherein .lambda. is an anion, R is a divalent aryl group, R' is a monovalent or divalent aryl or alkyl group, A is a divalent group or a direct bond and examples of the R--A--R' are diarylamine (A; --NH--), diphenyl A; direct bond), diphenyl oxide (A; --O--), diaryl methane (A; --CH.sub.2 --), stilbene (A; --CH=CH--) and diaryl or dialkyl sulfide (A; --S--).

Specific examples of the compounds of the above type are as follows:

Para-diazophenyl amine

4-diazo-2,5,4'-triethoxydiphenyl amine

4-Diazo-2,5,4'-triethoxydiphenyl

4,4'-Bis-diazo-2,2',5,5'-tetrahydroxydiphenyl methane

Bis-diazo-8,8'-dichloro-5,5'-dimethoxy benzidine

4-Diazo-2,5-dimethoxyphenylethyl sulfide

4-Diazo-2,5-diethoxy-4'-methyl-diphenyl sulfide

Heterocyclic amine derivatives of the following general formula: ##EQU3## wherein X stands for an anion, Y and Z are groups which can be introduced into the benzene nucleus, and A is a direct bond (phenyl pyrrolidine) or a divalent group such as --O-- (morpholine), --S-- (thiomorpholine) and methylene (phenylpiperidine).

Specific examples of the compounds of this type are as follows:

4-Diazo-2,5-dibutoxy-N-phenyl morpholine

4-Diazo-2,5-diethoxy-N-phenyl morpholine

4-Diazo-2-methoxy-N-thio morpholine

4-Diazo-N-phenyl piperidine

4-Diazo-N-phenyl pyrrolidine

4-Diazo-2,5-di-n-butoxy-N-phenyl piperidine

Other derivatives of 4-Diazo-N-phenyl heterocyclic amines.

N,N-Substituted ortho-phenylene diamine derivatives and orthoamino-phenol derivatives.

Specific examples of the compounds of this type are as follows:

2-Diazo-4-methylmercapto-N,N'-dimethyl aniline

2-Diazo-5-benzoylamino-N,N' -dimethyl aniline

2Diazo-1-naphthol-5-sulfonic acid

The above-mentioned diazonium compounds may be used in the form of a relatively stable salt with sulfuric acid or hydrochloric acid. They may be also used in the form of a double salt with zinc chloride, tin chloride, aluminum sulfate or the like. Further, they may be used in a state stabilized by an aryl sulfonate (in the form of a diazonium salt of an aromatic sulfonic acid), a diazosulfonate or the like.

The light exposure of the photosensitive material and the transfer of the color former of this invention to the photosensitive surface of the photosensitive material may be effected coincidentally. For instance, when a mercury lamp is used as the light source for exposure, the heat transfer of the coupler (a) may be effected coincidentally with the exposure by the heat conveyed through a cylinder glass of the light source maintained at a relatively high temperature. Of course, the heat transfer of the coupler (a) may be also effected by the radiation heating of an image of the original. The heat transfer of the coupler (a) may be effectively performed at a temperature above 50.degree.C., preferably 60.degree. - 100.degree.C., though a preferable heating temperature varies to some extent depending on the type of the coupler (a) and heating time.

It is also possible to adopt a method comprising piling the above-mentioned original for multicolor development and the photosensitive material, passing the assembly through a heated roller or an infrared radiation zone to heat the coupler layer of the original at the above-mentioned temperature and to effect the heat transfer of the coupler (a), and then passing the same through an exposure zone to effect the exposure of the photosensitive material.

It is also possible to adopt a method in which the exposure and heat transfer are conducted in an order reverse to that of the above method, namely a method comprising forming an assembly of the original for multicolor development and the photosensitive material, passing the assembly through an exposure zone to effect the exposure of the photosensitive material and then passing the same through a heating zone to effect the heat transfer of the coupler (a).

Since the color former of this invention contains a thermosublimative, organic, solid transfer promoter as well as the coupler (a), in the heat transfer of the coupler (a) the heat transfer temperature can be considerably lowered by the interaction of the coupler (a) and the transfer promoter, as compared with the case where the coupler (a) is used singly. Further, when a plurality of couplers (a), (a'), (a") . . . forming colors differing in hues are coated on predetermined portions of an original to be copied and the heat transfer is conducted, the heat transfer temperatures of couplers (a), (a'), (a") . . . can be approximated because of the presence of the thermosublimative, organic, solid transfer promotor.

The photosensitive material which has been thus exposed to light and on a predetermined portion of which the coupler (a) has been heat-transferred, is developed by customary known developing methods. The coupler (b) may be either contained in the photosensitive material in advance or made present in the developer. The development may be conducted by either a dry method or a wet method. When a photosensitive material containing coupler (b) as well as diazonium salt (c) is used, it is preferred that prior to the development the photosensitive material on which the coupler (a) has been heat-transferred is subjected to an affinity-increasing pre-treatment with a treating liquor comprising, singly or in combination, an aliphatic alcohol, an aromatic solvent, an ester, a glycol or a liquid having OH groups and boiling at 100.degree. - 200.degree.C. such as water or high boiling point alcohols, to thereby attain a uniform contact between the heat-transferred coupler (a) and the diazonium salt remaining unexposed. In conducting the above pre-treatment it is desired to allow the above treating liquor to contact the photosensitive material while keeping the liquor in the liquid or vapor state. In the case of the dry development, the development may be accomplished sufficiently only by exposing the light-exposed photosensitive material to a mixture of ammonia and steam. When a one-component-type photosensitive sheet for wet development is used, the development can be accomplished by dipping, roller coating or spraying methods with use of a liquid developer having, for instance, the following recipe: Coupler (b) 0.2 - 5 % Alkali 0.5 - 10 % Reducing agent 0 - 20 % Surfactant 0 - 0.5 % Water balance

When a two-component-type photosensitive sheet for wet development is used, the development may be accomplished by contacting the light-exposed photosensitive sheet with a liquid developer containing an alkali.

Thus multi-colored reproductive copies in which the portion corresponding to the predetermined portion of the original is colored with a dyestuff (a)-(c) and other portions are colored with a dyestuff (b)-(c) can be obtained.

The diazo-type multicolor reproduction process with use of the color former of this invention will now be explained by referring to the accompanying drawings.

FIGS. 1 and 2 are diagrams illustrating the process for obtaining multi colored copies with use of the color former of this invention.

In the embodiment of this invention illustrated in FIG. 1, different thermovolatile or thermosublimative couplers 2' and 3' are coated on the back surfaces of images 2 and 3, respectively, of an original having images 1, 2 and 3. When the so formed original for multicolor development is overlapped on a photosensitive paper, and exposed to light emitted from a suitable light source, latent images 1", 2" and 3" corresponding to images 1, 2 and 3 are formed on the photosensitive layer and couplers 2' and 3' are transferred on the upper surface of the photosensitive layer by the heat from the light source. When this photosensitive sheet is developed, the diazonium salt in latent images 2" and 3" of the photosensitive layer reacts selectively with transferred couplers 2' and 3', while the diazonium salt in latent image 1" reacts with a coupler contained in the photosensitive layer. As a result a reproductive copy which has images 11, 12 and 13 colored in different hues is obtained.

FIG. 2 is a view illustrating an embodiment similar to the above embodiment shown in FIG. 1, except that a heat-transferable sheet containing coupler 2' and another heat-transferable sheet containing coupler 3' are applied to the back surfaces of images 2 and 3, respectively.

When the color former of this invention is used for the multicolor reproduction, it is possible to heat transfer the coupler (a) from the predetermined portion of the original to be copied in a different hue to the photosensitive material at a relatively low temperature, i.e., a temperature only 10.degree. - 20.degree.C. higher than the temperature adopted in the ordinary diazo-type reproduction process, and therefore, it is possible to obtain a copy in which the portion corresponding to the predetermined portion of the original is colored selectively in a different hue very distinctly without substantial mingling of colors. Further, formation of a plurality of different colors may be accomplished by one development treatment. Once an original is treated with the color former of this invention, at least 5 multi-colored copies, usually 20 - 100 multi-colored copies, can be obtained from the original, and it is unnecessary to treat the original repeatedly every time one copy is formed. Further, the treated original used for the multicolor reproduction can be returned to the original state only by peeling off the layer or sheet of the color former applied thereto or by heating the color former-colored original at about 100.degree.C.

The multicolor reproduction process with use of the color former of this invention is effectively and conveniently applied when copies in which special portions are colored in different hues are desired, and further, ordinary multi-colored copies can be obtained with ease in accordance with this invention.

This invention will now be explained by referring to examples.

Examples of Preparation of Ink-like Color Former Composition for Use in Multicolor Reproduction:

EXAMPLE 1

An ink-like composition of the following recipe is prepared as a yellow color-forming agent for treating the back surface of an original: Acetoacetic anilide 20 g Alkyd resin 3 g Camphor 15 g Diethylene glycol 5 g Tolyol balance Total 100 ml

The above composition is directly used as a material to be coated on the back surface of a portion of the original desired to be reproduced in yellow by means of a brush, a coating roller or a sprayer, or after it has been charged in a felt pen or a ball pen, it is used as a material for treating the back surface of a portion of the original desired to be reproduced in yellow.

EXAMPLE 2

An ink-like composition for forming a yellowish orange color is prepared by using acetoacetic-o-chloroanilide instead of the acetoacetic anilide of Example 1.

EXAMPLE 3

An ink-like composition of the following recipe is prepared as a red color-forming agent for treating the back surface of an original:

1-Phenyl-3-methylpyrazolone (5) 25 g Hydrochloric acid (36 %) 5 ml Naphthalene 15 g Glycerine 10 g Ethanol balance Total 100 ml

The above composition is directly used as a material to be coated on the back surface of a portion of the original to be reproduced in red by means of a brush, a coating roller or a sprayer, or after it has been charged in a felt pen or a ball pen, it is used as a material for treating the back surface of a portion of the original to be reproduced in red.

EXAMPLE 4

An ink-like composition of the following recipe is prepared as a brown color-forming agent for treating the back surface of an original:

Resorcin 20 g Vinyl acetate resin 3 g Oxalic acid 15 g Methanol 60 ml Water balance Total 100 ml

The above composition is directly used as a material to be coated on the back surface of a portion of the original desired to be reproduced in brown by means of a brush, a coating roller or a sprayer, or after it has been charged in a felt pen or a ball pen, it is used as a material for treating the back surface of a portion of the original desired to be reproduced in brown.

EXAMPLE 5

An ink-like composition of the following recipe is prepared as a blue color forming agent for treating the back surface of an original:

2,3-Dihydroxynaphthalene 20 g Alkyd resin 3 g Bornane 15 g Ethylene glycol 10 g Ethanol balance Total 100 ml

The above composition is directly used as a material to be coated on the back surface of a portion of the original desired to be reproduced in blue by means of a brush, a coating roller or a sprayer, or after it has been charged in a felt pen or a ball pen, it is used as a color former for treating the back surface of a portion of the original to be reproduced in blue.

EXAMPLE 6

An ink-like composition of the following recipe is prepared as a reddish brown color-forming agent for treating the back surface of the original:

Dimethyl-m-aminophenol 20 g Naphthalene 15 g Glycerine 10 g Ethanol balance Total 100 ml

The above composition is directly used as a color former to be coated on the back surface of a portion of the original predetermined to be copied in reddish brown by means of a brush, a coating roller or a sprayer, or after it has been charged in a felt pen or ball pen, it is used as a color former for treating the back surface of a portion of the original to be copied in reddish brown.

Examples of Preparation of Waxy Color Former Composition for Use in Multicolor Reproduction:

EXAMPLE 7

A waxy composition to be used as a yellow color-forming agent for treating the back surface of an original is prepared by heat melting

Acetoacetic acid anilide 25 g Camphor 15 g Stearic acid 100 g Paraffin 50 g Terra abla 50 g

and solidifying the melt.

The above composition is molded into a crayon stick-like or chalk-like form and is used as a color former to be coated on the back surface of a portion of the original desired to be reproduced in yellow.

EXAMPLE 8

A waxy composition to be used as a yellowish brown color-forming agent is prepared by heat melting

Pyrogallol 20 g Menthol 15 g Paraffin 50 g Terra abla 70 g Haze wax 20 g Stearic acid 100 g Magnesium carbonate 20 g

and solidifying the melt.

The so formed composition is molded into a crayon stick-like or chalk-like form and is used as a material for coating the back surface of a portion of an original desired to be reproduced in a different hue.

EXAMPLE 9

To the composition of Example 8 100 g of mineral oil and 30 g of oleic acid are added, and the mixture is kneaded in a ball mill. Then, the kneaded mixture is coated on a substrate such as paper to obtain a pressure-sensitive copy sheet. The so formed copy sheet is overlapped on the back surface of an original and the pressing is effected thereon by means of a typewriter or other writing tool. Thus, the sheet is used as a material for forming a layer of the waxy color former agent on the back surface of a portion of the original desired to be reproduced in a different hue.

EXAMPLE 10

A waxy composition for forming a red color is prepared by heat melting

1-Phenyl-3-methylpyrazolone (5) 25 g p-Dichlorobenzene 15 g Paraffin 50 g Stearic acid 100 g Diatomeceous earth 30 g Haze wax 20 g

and solidifying the melt.

The above composition is molded into a crayon stick-like or chalk-like form and is used as a material for coating the back surface of a portion of the original desired to be reproduced in a different hue.

EXAMPLE 11

To the composition of Example 10 100 g of mineral oil, 50 g oleic acid and 20 g of Permanent Red are added, and the mixture is kneaded in a ball mill to disperse additional components uniformly. Then, the kneaded mixture is coated on a substrate as paper to obtain a pressure-sensitive copy sheet. The so formed pressure-sensitive copy sheet is used as a material for forming a layer of the waxy color former composition on the back surface of a portion of the original to be copied in a different hue, in the same manner as described in Example 9.

EXAMPLE 12

A waxy color former composition for forming a blue color is prepared by heat melting

2,3-Dihydroxynaphthalene 30 g Naphthalene 15 g Stearic acid 100 g Paraffin 50 g Diatomaceous earth 30 g Haze wax 20 g

and solidifying the melt.

The above composition is molded into a crayon stick-like form and is used as a material to be coated on the back surface of a portion of the original desired to be reproduced into a different hue.

EXAMPLE 13

To the composition of Example 12 100 g of mineral oil, 30 g of oleic acid, 20 g of Oil Blue and 50 ml of ethanol are added. The mixture is well kneaded in a ball mill and coated on a substrate such as paper to form a pressure-sensitive copy sheet. The sheet is used as a material for forming a layer of the waxy color former composition on the back surface of the original to be reproduced in a different hue, in the same manner as described in Example 9.

Examples of Preparation of Coupler-Transferring Sheets Comprising Color Former:

EXAMPLE 14

A composition of the following recipe is prepared as a red color-forming agent for treating the back surface of an original:

1-Phenyl-3-methylpyrazolone (5) 25 g Camphor 15 g Triacetate resin 10 g Methanol 50 ml Acetone 50 ml

The above composition is coated on a transparent or semi-transparent sheet such as polyester film by means of a rod coater and dried at a relatively low temperature (40.degree. - 50.degree.C.) to form a sheet for heat-transferring the coupler. After being cut into a desired size according to need, the sheet is used as a material to be applied to the back surface of a portion of an original desired to be reproduced in a different hue.

EXAMPLE 15

A composition of the following recipe is prepared as a brown color-forming agent for treating the back surface of an original:

m-Aminophenol 25 g Anthranic acid 15 g Triacetate resin 10 g Methanol 50 ml Acetone 50 ml

The above composition is coated on a transparent or semi-transparent sheet such as polyester film by means of a rod coater and dried at a relatively low temperature (40.degree. - 50.degree.C.) to form a sheet for heat-transferring the coupler. After being cut into a desired size according to need, the sheet is used as a material to be applied to the back surface of a portion of the original desired to be reproduced in a different hue.

EXAMPLE 16

A composition to be used as a brown color-forming agent for treating the back surface of an original is prepared by using pyrogallol instead of 1-phenyl-3-methylpyrazolone (5) in Example 14. From this composition a sheet is formed for heat-transferring the coupler capable of forming a brown color.

EXAMPLE 17

A composition to be used as a blue color-forming agent for treating the back surface of an original is prepared by using 1,6-dihydroxynaphthalene instead of 1-phenyl-3-methylpyrazolone in Example 14. From this composition a sheet is prepared for heat transferring the coupler capable of forming a blue color.

Application of Color-Forming Agents to Diazo-type Multicolor Reproduction:

EXAMPLE 18

Multicolor-forming diazo-type photosensitive paper in use for wet development

First, 10 g of 4-diazo-2,5-diethoxy-benzoylaniline chloride 1/2ZnCl.sub.2, 8 g of citric acid, 0.1 g of Patent Blue and 10 g of dextrin are dissolved successively in water, and the amount of the solution is adjusted to 1 liter by controlling the amount of water added. The so formed solution is coated on a base paper of a photosensitive sheet by a customary coating method employing an air knife coater, and dried to form a photosensitive sheet.

The sheet is overlapped on an original in which the back surface of a portion is treated with the ink-like color former composition prepared in Example 1 and the back surface of another portion is treated with the color former composition prepared in Example 3. Then the assembly is heated and light exposed by means of a mercury lamp and developed with a liquid developer of the following recipe:

NW acid 20 g Potassium carbonate 20 g Sodium bicarbonate 30 g Sodium thiosulfate 40 g Activator 1 g Water balance Total 1 liter

by a customary developing method using a roller or sprayer.

As a result a clear three color copy in which a portion corresponding to the portion treated with the composition of Example 1 is colored in a yellow color, a portion corresponding to the portion treated with the composition of Example 3 is colored in red and another portion corresponding to the untreated portion is colored in blueish violet is obtained.

EXAMPLE 19

Multicolor-Forming Diazo-type Photosensitive Sheet for Dry Development

A solution of the following recipe is prepared:

4-Diazo-N-ethyl-N-.beta.-hydroxyethylaniline chloride 1/2ZnCl.sub.2 10 g Diethylene glycol 50 g Citric acid 20 g Bis-?5-hydroxy-7-sulfonaphthyl(2)!amine 15 g Zinc chloride 40 g Thiourea 30 g Patent Blue 0.1 g Water balance Total 1 liter

The solution is coated on a base paper by a customary coating procedure such as using an air knife coater and dried to form a photosensitive sheet.

The sheet is piled on an original in which one portion of the back surface is treated with the color former composition prepared in Example 2, another portion of the back surface is treated with the color former composition prepared in Example 3 and still another portion of the back surface is treated with the color former composition of Example 5. Then, the assembly is heated and exposed to light by means of a mercury lamp to form a latent image of the diazonium salt.

Next, the so treated sheet is subjected to development with gasified ammonia and steam. Thus, there is obtained as a result a clear multicolor copy in which a portion corresponding to the portion treated with the material of Example 2 is colored in yellowish orange, a portion corresponding to the portion treated with the material of Example 3 is colored in reddish brown, a portion corresponding to the material of Example 5 is colored in bluish violet, and a portion corresponding to the untreated portion of the original is colored in dark blue is obtained.

EXAMPLE 20

Multicolor-forming diazo-type photosensitive paper in use for dry development

A solution of the following recipe is prepared:

4-Diazo-N,N-dimethyl-aniline chloride.1/2ZnCl.sub.2 10 g Diethylene glycol 40 g Citric acid 50 g 2,3-Dihydroxynaphthalene-6- sulfonic acid 20 g Zinc chloride 50 g Thiourea 50 g Patent Blue 0.1 g Water balance Total 1 liter

In the same manner as in Example, 18, a photosensitive paper is prepared from the above solution by coating and drying. The photosensitive paper is piled on an original, a portion of the back surface of which is treated with the coupler-heat-transferring sheet prepared in Example 14. Then the assembly is heated and printed by means of a mercury lamp, followed by development with gaseous ammonia and steam. As a result a clear two-color reproductive copy in which a portion corresponding to the portion treated with the treating agent of Example 14 is colored in red and another portion corresponding to the untreated portion is colored in dark blue is obtained.

Example 21

Multicolor-forming photosensitive paper in use for dry development

A solution of the following recipe is prepared:

4-Diazo-N,N-dimethylaniline chloride.1/2ZnCl.sub.2 15 g Ethylene glycol 50 g Citric acid 20 g 2,7-Dihydroxynaphthalene- 3,6-disulfonic acid sodium salt 8 g Zinc chloride 20 g Thiourea 100 g 1,3,6-Naphthalene-trisulfonic acid sodium salt 20 g Patent Blue 0.1 g Water balance Total 1 liter

By a customary coating method such as using an air knife coater, a photosensitive paper is prepared from the above solution. The photosensitive paper is overlapped on an original in which a portion of the back surface is treated with the waxy composition prepared in Example 8 and another portion of the back surface is treated with the composition prepared in Example 10. The assembly is exposed to light and heated by means of a mercury lamp. Then, the so treated sheet is subjected to development with gasified ammonia and steam. As a result a clear three-color reproductive copy in which a portion corresponding to the portion of the original treated with the composition of Example 8 is colored in brown, a portion corresponding to the portion treated with the composition of Example 10 is colored in red, and other portion corresponding to the untreated portion of the original is colored in bluish violet is obtained.

EXAMPLE 22

Multicolor-forming photosensitive paper for dry development

A solution of the following recipe is prepared:

4-Diazo-N,N-diethylaniline chloride.1/2ZnCl.sub.2 20 g 2,7-Dihydroxynaphthalene-3,6- disulfonic acid sodium salt 15 g Diethylene glycol 50 g Tartaric acid 20 g Resorcinol monomethyl ether 10 g Zinc chloride 10 g Thiourea 50 g 1,3,6-Naphthalene-trisulfonic acid sodium salt 20 g Patent Blue 0.1 g Water balance Total 1 liter

The above solution is applied to a photosensitive paper substrate by a customary coating method such as using an air knife coater, and the resulting photosensitive sheet is piled on an original in which the back surface of a part of an image is treated with the ink-like composition obtained in Example 3, the back surface of another part of the image is treated with the composition of Example 4 and the back surface of still another part is treated with the composition of Example 5. Then, the assembly is heated and printed at 70.degree. - 80.degree.C. by means of a mercury lamp, and the so treated photosensitive sheet is developed with gaseous ammonia and steam. As a result a four-colored copy of a clear color contrast is obtained in which a portion corresponding to the portion treated with the composition of Example 3 is colored in red, a portion corresponding to the portion treated with the composition of Example 4 is colored in yellowish brown, a portion corresponding to the portion treated with the composition of Example 5 is colored in blue, and a portion corresponding to the untreated portion of the original is colored in black.

EXAMPLE 23

Multicolor-forming diazo-type photosensitive paper for dry development for forming second original

A solution of the following recipe is prepared: 4-Diazo-N,N-dimethylaniline chloride 1/2.DELTA.nCl.sub.2 30 g Ethylene glycol 50 g Tartaric acid 20 g 2,4,2',4'-Tetrahydroxydiphenyl 11 g sulfide Thiourea 25 g Zinc chloride 50 g Patent Blue 0.1 g Water balance Total 1 liter

The above solution is coated on a semi-transparent paper for second original such as tracing paper and dried to form a photosensitive paper. The photosensitive paper is piled on an original, a portion of the back surface of which is treated with the waxy color former composition prepared in Example 12. Then the assembly is heated and printed by means of a mercury lamp, followed by development with gaseous ammonia and steam. As a result a clear two-color reproductive copy usable as the intermediate second original is obtained in which a portion corresponding to the portion of the original treated with the composition of Example 12 is colored in red and another portion corresponding to the untreated portion of the original is colored in yellowish brown.

EXAMPLE 24

Multi-color-forming photosensitive paper for dry development

A solution of the following recipe is prepared:

4-Diazo-N-ethyl-N-hydroxyethylaniline chloride.1/2ZnCl.sub.2 15 g Diethylene glycol 50 g Citric acid 30 g .alpha.-resorcylic acid ethanol amine 8 g Zinc chloride 50 g Thiourea 25 g Patent Blue 0.1 g Water balance Total 1 liter

By a customary coating method such as using an air knife coater, the above solution is applied to a substrate of a photosensitive paper and dried. The so formed photosensitive paper is piled on an original, a portion of the back surface of which is treated with a coupler-heat-transferring sheet prepared in Example 17, and the assembly is heated at 60.degree. - 70.degree.C. and printed by means of a mercury lamp, followed by development with gaseous ammonia and steam. As a result a clear two-color reproductive copy without any substantial mingling of colors is obtained, in which a portion corresponding to the portion of the original treated with the sheet obtained in Example 17 is colored in blue and the remaining portion corresponding to the untreated portion of the original is colored in red.

EXAMPLE 25

Multicolor-forming sensitive paper in use for either dry or wet development

A solution of the following recipe is prepared:

4-Diazo-2,5-dibutoxy-N-phenyl- morpholine.1/2ZnCl.sub.2 15 g Citric acid 30 g Diethylene glycol 40 g .beta.-Hydroxynaphthonic acid aminoethyl amine (hydrochloride) 7 g Thiourea 40 g Zinc chloride 30 g Patent Blue 0.1 g Water balance Total 1 liter

From the above solution, a photosensitive paper is prepared by conducting the coating and drying in the same manner as in Example 18. The so formed photosensitive paper is piled on an original, a portion of the back surface of which is treated with the pressure-sensitive sheet prepared in Example 9 and another portion of the back surface of which is treated with the pressure-sensitive sheet prepared in Example 11. Then the assembly is heated and printed by means of a mercury lamp, followed by development with gaseous ammonia and steam or with an alkaline liquid developer of the following recipe:

Potassium carbonate 20 g Sodium thiosulfate 40 g Sodium bicarbonate 30 g Potassium tetraborate 5 g Water balance Total 1 liter

As a result a clear three-color reproductive copy without any substantial mingling of colors is obtained, in which a portion corresponding to the portion of the original treated with the pressure-sensitive sheet of Example 9 is colored in brown, a portion corresponding to the portion of the original treated with the pressure-sensitive sheet of Example 11 is colored in red and the remaining portion corresponding to the untreated portion of the original is colored in blue.

EXAMPLE 26

Multicolor-forming film

A solution of the following recipe is prepared:

4-Diazo-2,5-dibutoxy-N-phenyl morpholine.1/2ZnCl.sub.2 15 g Citric acid 10 g .beta.-Hydroxynaphthoic acid ethanol amine 7 g Triacetate resin 15 g Oil Blue 0.2 g Acetone 400 ml Methanol 700 ml

The solution is coated on a polyester film by a rod coater and dried at a relatively low temperature (40.degree. - 50.degree.C.) by warm air to form a photosensitive film. The film is piled on an original in which a part of the back surface of an original image is treated with the color-forming agent prepared in Example 3 and another part of the back surface of the original image is treated with the color-forming agent prepared in Example 4. The assembly is exposed to light by a mercury lamp and heated and printed. The photosensitive film containing a latent image of the diazonium salt is developed with gasified ammonium and steam. As a result a clear three-color reproductive copy without any substantial mingling of colors is obtained, in which a portion corresponding to the part treated with the treating material of Example 3 is colored in red, a portion corresponding to the part treated with the treating material of Example 4 is colored in brown, and another portion corresponding to the untreated part of the original is colored in blue.

COMPARATIVE EXAMPLE 1

This example illustrates results of comparative experiments conducted to confirm effects attained by the incorporation of the thermosublimative, organic, solid transfer promotor in the color former of this invention.

EXPERIMENTAL PROCEDURES

Four ink-like color-forming compositions of the following recipes are prepared.

______________________________________ Recipe 1 ______________________________________ 1-Phenyl-3-methylpyrazolone (5) 25 g Ethanol balance Total 100 ml Recipe 2 1-Phenyl-3-methylpyrazolone (5) 25 g Camphor 15 g Ethanol balance Total 100 ml Recipe 3 Resorcin 25 g Ethanol balance Total 100 ml Recipe 4 Resorcin 25 g Naphthalene 15 g Ethanol balance Total 100 ml ______________________________________

Each of the above solutions is coated on the back surface of a semi-transparent original (tracing paper; Chemical No. 60) in an amount of about 0.2 g/m.sup.2. The so coated original is dried to form a sample sheet original. Then, the sample sheet is piled on the photosensitive sheet prepared in Example 21 in a manner such that the treated surface of the sample is in face-to-face contact with the photosensitive layer of the photosensitive sheet. Then, the assembly is allowed to pass through hot rolls maintained at 50.degree.C., 60.degree.C., 70.degree.C., 80.degree.C. and 90.degree.C., respectively, to effect the heat transfer of the thermovolatile or thermosublimative coupler. Then, the so treated photosensitive sheet is subjected to the development with gaseous ammonia and steam. With respect to each sample original, the number of copies of a distinct color contrast obtained at each heat transfer temperature is counted. Results are shown in Table 1 below.

Table 1 ______________________________________ Number of Copies of Distinct Color Contrast Heat Transfer Temperature (.degree.C.) Recipe No. 50 60 70 80 90 ______________________________________ 1 0 3 7 15 32 2 0 5 14 27 50 3 3 11 20 35 21 4 5 18 42 23 13 ______________________________________

COMPARATIVE EXAMPLE 2

This example illustrates results of experiments conducted to confirm the effect of the thermosublimative, organic, solid transfer promotor for accelelating the volatilization or sublimation of the thermovolatile or thermosublimative coupler.

EXPERIMENT PROCEDURES

As the thermovolatile or thermosublimative coupler sample 1-phenyl-3-methylpyrazolone (5) and resorcin are selected. Each of the sample chemicals is sufficiently ground in a mortar and is sufficiently dried in a silica gel desiccator. A precisely weighed amount (0.3 g) of each sample is charged in a vessel having a certain inner surface area and subjected to a heat treatment at 100.degree.C., 110.degree.C. and 120.degree.C. The weight of the sample is determined at certain time intervals and the weight loss is calculated each time.

Then, each sample is blended with 1.5 g of camphor (special grade) and the blend is sufficiently mixed and ground in a mortar. Then, the blend is subjected to the same heat treatment as above to determine the weight loss of the blend. Then, the weight loss of the coupler alone is calculated by reducing the weight loss of camphor alone determined separately, from the above determined weight loss of the blend. Thus, the effect of camphor for promoting the volatilization or sublimation of the sample coupler is examined. Results are shown in Tables 2 and 3 below.

Table 2 ______________________________________ Weight Loss (mg) of 1-Phenyl-3-Methylpyrazolone (5) Treatment Time Treatment Temperature (hr) (.degree.C.) ______________________________________ 100 110 120 0.5 1.03 3.21 7.06 (3.96) (9.03) (18.61) 1.0 2.87 6.76 12.22 (8.21) (17.93) (35.96) 2.0 5.12 13.86 24.58 (15.82) (35.16) (71.28) ______________________________________

Table 3 ______________________________________ Weight Loss (mg) of Resorcin Treatment Time Treatment Temperature (hr) (.degree.C.) ______________________________________ 100 110 120 0.5 4.82 9.58 13.86 (11.38) (15.92) (22.54) 1.0 10.70 18.90 26.12 (21.72) (29.48) (46.14) 2.0 21.23 35.74 53.47 (45.18) (59.27) (93.54) ______________________________________

In Tables 2 and 3, the values are values in parenthesis obtained when d-camphor is incorporated in the sample coupler.

From the results of Comparative Examples 1 and 2, the following can be concluded.

As is seen from the results shown in Table 1, the use of the color former of this invention increases the number of copies by 7 sheets at 70.degree.C., by 12 sheets at 80.degree.C. and by 18 sheets at 90.degree.C. in the case of 1-phenyl-3-methylpyrazolone (5), as compared with the use of the coupler alone. Accordingly, it is construed that the heat transfer temperature may be lowered by about 10.degree. - 15.degree.C. with the use of the color former of this invention comprising the thermovolatile or thermosublimative coupler and the thermosublimative, organic, solid transfer promotor. In the case of resorcin, the use of the color former of this invention increases the number of copies by 7 sheets at 60.degree.C. and by 22 sheets at 70.degree.C. Accordingly, it is construed that also in this case the heat transfer temperature may be lowered by about 10.degree. - 15.degree.C. with the use of the color former of this invention.

As is seen from the results of Comparative Example 2 shown in Tables 2 and 3, when comparison is made at the same treatment temperature, in the case of the color former of this invention the weight loss of 1-phenyl-3-methylpyrazolone (5) is about 2.5 times as large as in the case of the color former free of camphor, and the weight loss of resorcin in the case of the color former of this invention is about 2 times as large as in the case of the color former comprising resorcin alone. Accordingly, it is construed that the heat transfer temperature may be lowered by about 10.degree. - 15.degree.C. with the use of the color former of this invention.

In view of the foregoing, it can be readily understood that when the thermosublimative, organic, solid transfer promotor is used in combination with a thermovolatile or thermosublimative coupler, the efficiency of transfer of the coupler can be greatly improved.

Claims

What we claim is:

1. A waxy color former composition of crayon stick-like form or a chalk-like form for treating the back surface of an original in diazo-type multicolor reproduction, which consists essentially of

a. a thermovolatile or thermosublimable azo coupler; and

b. a solid organic thermosublimable compound selected from the group consisting of camphor, naphthalene, bornane, menthol, and p-dichlorobenzene,

said components (a) and (b) dispersed in a wax.

2. The waxy color former composition of claim 1, in which said composition consists essentially of

a. 0.5-40.0% by weight of a thermovolatile or thermosublimable azo coupler;

b. 0.5-25% by weight of a solid organic thermosublimable compound selected from the group consisting of camphor, naphthalene, bornane, menthol, and p-dichlorobenzene,;

c. 80-5% by weight of a wax; and

d. 0-10% by weight of color material.

3. The waxy color former composition of claim 1 in which said thermovolatile or thermosublimable azo coupler is at least one member selected from the group consisting of phenol compounds, hydroxynaphthalene compounds, aniline compounds and active methylene group-containing compounds.

4. The waxy color former composition of claim 1 in which said composition consists essentially of:

5. The waxy color former composition of claim 1 in which said composition consists essentially of:

6. The waxy color former composition of claim 1 in which said composition consists essentially of:

7. The waxy color former composition of claim 1 in which said composition consists essentially of:

8. The waxy color former composition of claim 1 wherein said solid organic thermosublimable compound (b) is camphor.

9. The waxy color former composition of claim 1 wherein said solid organic thermosublimable compound (b) is naphthalene.

10. The waxy color former composition of claim 1 wherein said solid organic thermosublimable compound (b) is bornane.

11. The waxy color former composition of claim 1 wherein said solid organic thermosublimable compound (b) is menthol.

12. The waxy color former composition of claim 1 wherein said solid organic thermosublimable compound (b) is p-dichlorobenzene.

13. An ink-like color former composition for treating the back surface of an original in the diazo-type multicolor reproduction, which consists essentially of

a. 5.0-40.0% by weight of a thermovolatile or thermosublimable azo coupler;

b. 5.0-30.0% by weight of a solid organic thermosublimable compound selected from the group consisting of camphor, naphthalene, bornane, menthol, and p-dichlorobenzene;

c. 0-0.3% by weight of a color material; and

d. 0-5.0% by weight of a resinous binder, said components (a), (b), (c) and (d) dispersed in a dispersion medium selected from aliphatic alcohols, aromatic solvents and neutral liquids containing OH groups, said dispersion medium boiling at 100.degree.-250.degree.C.

14. The ink-like color former composition of claim 13 wherein said solid organic thermosublimable compound (b) is camphor.

15. The ink-like color former composition of claim 13 wherein said solid organic thermosublimable compound (b) is naphthalene.

16. The ink-like color former composition of claim 13 wherein said solid organic thermosublimable compound (b) is bornane.

17. The ink-like color former composition of claim 13 wherein said solid organic thermosublimable compound (b) is menthol.

18. The ink-like color former composition of claim 13 wherein said solid organic thermosublimable compound (b) is p-dichlorobenzene.

19. The ink-like color former composition of claim 13 in which said thermovolatile or thermosublimable azo coupler is at least one member selected from the group consisting of phenol compounds, hydroxynaphthalene compounds, aniline compounds, and active methylene group-containing compounds.