JPH01292334A - Image forming method for thermodevelopment type copying material - Google Patents

Abstract

PURPOSE:To make possible to apply the low temp. development capable ofobtaining a high coloring density, to the title material by incorporating a diazo compd. to be mounted on a photosensitive layer, in a microcapsule, and by uniformly wetting the whole of the photosensitive layer immediately before a thermal development. CONSTITUTION:The diazo compd., a coupling component and a coloring auxiliary agent are prevented to be allowed to contact with each other in the state of preserving them at a room temp. by incorporating the diazo compd. in the microcapsule, in the photosensitive layer capable of applying the thermal development, and the generation of the fog is prevented. And, as the whole of the photosensitive layer is wetted immediately before the thermal development, the sufficient high coloring density of the copying material is obtd. by supplying a moisture (a wetting water) to said material even in case that the development temp. is reduced by >=30 deg.C comparing with the case that the moisture is not supplied to the material. The shell of a capsule is constituted of a polymer (is composed of at least one kind of polyurethane and polyurea) which is formed by polymerizing the polymerizable substance around a core substance after emulsifying the core substance. The wetting water is composed of an aqueous solution contg. an anionic or a nonionic surface active agent.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a copying material in which a diazo compound (diazonium salt) is encapsulated in microcapsules, and which has a particularly good shelf life and a high color density even when subjected to low-temperature thermal development. The present invention relates to a copying material that can be obtained and an image forming method thereof.

<Prior Art> There are three types of copying materials that utilize the photosensitivity of diazo compounds. One type is known as a wet development type, in which a photosensitive layer containing a diazo compound and a coupling component as main components is provided on a support.
This material is superimposed on the original, and after exposure, it is developed with an alkaline solution. The second type is known as a dry development type, which, unlike the wet type, develops with ammonia gas. The third type is known as a heat-developable type, and includes a type that contains an ammonia gas generating agent such as urea that can generate ammonia gas when heated in the photosensitive layer, or a type that contains an ammonia gas generating agent such as urea that can generate ammonia gas when heated, or a type that contains ammonia gas generating agent such as trichloroacetic acid in the photosensitive layer. There are types that contain an alkali salt of an acid that loses its properties as an acid when heated, and types that use a higher fatty acid amide as a coloring aid and activate the diazo compound and coupling component by heating and melting.

In addition to maintenance problems such as the need for replenishing and discarding the developer as it uses a developer and the large size of the device, the wet type also has problems with maintenance, such as the fact that it is wet immediately after copying, making it difficult to make additions immediately. There are several problems such as copy images not being able to withstand long-term storage. In addition, like the wet type, the dry type requires replenishment of developer, requires gas absorption equipment to prevent the generated ammonia gas from leaking outside, and therefore requires larger equipment.
There are problems such as the smell of ammonia immediately after copying. On the other hand, unlike the wet and dry types, the heat-developable type has the advantage of maintenance because it does not require a developing solution. Moreover, if the temperature is not controlled to about ±10° C., insufficient development may occur or the color tone may change, resulting in a problem of increased equipment cost. Furthermore, the diazo compound used for such high-temperature development is required to have high heat resistance, but such compounds are often disadvantageous in forming high concentrations. Low temperature development (90°C to 130'C
) have been attempted, but they have the drawback of decreasing the shelf life of the material itself.

As described above, although the thermal development type is expected to have sufficient advantages in terms of maintenance compared to the wet and dry types, the current situation is that it has not yet become the mainstream of diazo copying systems.

Now, in order to obtain the desired color density by heating a material in which a layer containing a diazo compound, a coupling component, and a coloring aid is provided on a support, each component instantly melts, diffuses, and reacts by heating. It is necessary to generate a coloring pigment by If we design a material that can sufficiently develop color and obtain a high concentration even at low heating temperatures, there is always the possibility that this reaction will occur even while it is stored at room temperature before copying, resulting in white color. This appears as a phenomenon in which the bare skin becomes colored.

In order to solve this incompatible problem, the inventors of the present invention made extensive studies and found that a copying material is provided with a heat-developable photosensitive layer containing a diazo compound, a coupling component, and a coloring aid on a support. discovered that one basic solution is to contain the diazo compound in microcapsules. However, this alone did not produce sufficient effects, and further investigation led to the present invention.

Accordingly, a first object of the present invention is to provide a copying material and an image forming method thereof that can obtain high color density even by low-temperature development.

A second object of the present invention is to provide a copying material that has a good shelf life, that is, a low density of background coloring (fog) during storage before copying.

A third object of the present invention is to provide a copying material which exhibits excellent long-term preservation of copy images (lower decrease in color density and smaller increase in background density when stored in bright and dark places).

A fourth object of the present invention is to provide a copying material with excellent water resistance, chemical resistance, and abrasion resistance.

A fifth object of the present invention is to provide a copying material that has a simplified layer structure and is easy to manufacture.

A sixth object of the present invention is to provide a simple and easy-to-maintain image forming method that uses the copying material described above and combines a latent image forming process by exposure and a developing process by heating.

Means for Solving the Problems> The above aspects of the present invention include a diazo compound, a diazo compound,
In a copying material provided with a heat-developable photosensitive layer containing a coupling component and a coloring aid, the diazo compound is contained in microcapsules. A first step in which a latent image is formed on the photosensitive layer by exposure corresponding to the image of the photosensitive layer, and the area other than the image forming area is fixed by light irradiation, and after the first step, the entire photosensitive layer of the copying material is soaked with moisture. This has been achieved by an image forming method characterized by comprising a second step of uniformly moistening the image, and a third step of developing by heating with a heating means. At this time, the wall of the microcapsule is preferably made of a polymer material formed around the core material by polymerization after emulsifying the core material of the microcapsule, and the polymer material is selected from polyurethane and polyurea. It is preferable that the material be formed of at least one kind of:

Effects> The copying material of the present invention enables a low thermal development temperature while maintaining a good shelf life. By containing the diazo compound in the microcapsules, the diazo compound, the coupling component, and the coloring aid are prevented from coming into contact with each other during storage at room temperature, thereby preventing the occurrence of fog. Furthermore, as a result of studies aimed at lowering the heat development temperature, the present inventors found that by providing moisture so that the entire photosensitive layer is uniformly wetted before heat development, compared to the case where this is not done, the present inventors found that We have made the surprising discovery that sufficiently high color density can be obtained even if the developing temperature is lowered by as much as 30°C.

However, it is consistent with the purpose of the present invention to provide this moisture before thermal development, and if the same amount of moisture is present in the photosensitive layer during storage before copying, a significant increase in the background J degree will occur. Accompany. Further, even when this water was provided into the photosensitive layer after thermal development, no further increase in color density was observed.

In the present invention, the water (dampening water) provided before thermal development can be conveniently provided by any method that uniformly wets the photosensitive layer. The amount is preferably adjusted to 0°19/m2 to 209/m2.

The dampening solution in the present invention can be an aqueous solution of a known 7-ionic or non-ionic surfactant in order to uniformly wet the photosensitive layer.

Preferred surfactants include sodium flukylbenzenesulfonate, sodium alkylsulfate, dioctyl sodium sulfosuccinate, polyalkylene glycol (
For example, polyoxyethylene nonylphenyl ether)
etc. can be mentioned.

The dampening water in the present invention can be provided to the photosensitive layer either from the support side or from the opposite side. In addition to the usual spray coating, dip coating, coating with a coating bar, etc., there are two methods to choose from, such as the method described in "Coating Engineering" by Yuji Harasaki, p. 253 (published by Asakura Shoten in 1973). I can do it.

The dampening solution used in the present invention may contain a pigment dispersant, a thickener, a flow modifier, an antifoaming agent, a foam inhibitor, a mold release agent, a coloring agent, etc. as appropriate. .

The diazo compound and the coupling component contained in the photosensitive layer of the present invention develop color when they come into contact with each other when heated, and the diazo compound decomposes when exposed to light of a specific wavelength before the coloring reaction. Photodegradable compounds are used.

The photodegradable diazo compound as used in the present invention mainly refers to aromatic diazo compounds, and more specifically refers to aromatic diazonium salts, diazosulfonate compounds, and diazoamino compounds. It is generally said that the photodecomposition wavelength of a diazo compound is its maximum absorption wavelength. Also, the maximum absorption wavelength of diazo compounds ranges from around 200 nm to 70 nm, depending on their chemical structure.
It is known that it changes to about 0 nm. (“Photodecomposition and chemical structure of photosensitive diazonium salts” by Takahiro Tsunoda and Ao Yamaoka, Journal of the Photographic Society of Japan 29 (4) pp. 197-205 (
1965)) That is, when a diazo compound is used as a photodegradable compound, it is decomposed by light of a specific wavelength depending on its chemical structure. Furthermore, by changing the chemical structure of the diazo compound, the hue of the dye after the reaction can be changed even when the same coupling component is used for the coupling reaction.

A diazo compound is a compound represented by the general formula ArN2X. (In the formula, Ar represents a monocyclic or unsubstituted aromatic ring,
N2 represents a diazonium group, and X represents an acid anion. ) In the present invention, a multicolor heat-developable copying material can be obtained by using diazo compounds having different photodecomposition wavelengths or different photodecomposition rates.

Specific examples of the diazo compound used in the present invention include the following examples.

4-Diazo-1-dimethylaminobenzene, 4-diazo-2-butoxy-5-chloro-1-dimethylaminobenzene, 4-diazo-1-methylbenzyl 7-minobenzene, 4-diazo-1-ethylhydroxyethyl 7-minobenzene , 4-diazo-1-diethylamino-3-methoxybenzene, 4-diazo-1-morpholinobenzene, 4-
Diazo-1-morpholino-2,5-dibutoxybenzene.

4-Diazo-1-tolylmercapto-2,5-jethoxybenzene, 4-diazo-1-piperazino-2-methoxy-5-chlorobenzene, 4-diazo-1-(N,N
-dioctyl7minocarponyl)benzene, 4-diazo-1-(4-tert-octylphenoxy)benzene, 4-diazo-1-(2-ethylhexanoylpiperidino) -2゜5-dibutoxybenzene, 4 -Diazo-1
-(2゜5-di-tert-7milphenoxyα-butanoylpiperidino)benzene, 4-diazo-1-(4
-methoxy)phenylthio-2,5-jethoxybenzene, 4-diazo-1-(4-methoxy)benzamide-
2,5-jethoxybenzene.

4-Diazo-1-pyrrolidino-2-methoxybenzene Specific examples of the acid that forms a diazonium salt with the above diazo compound include the following examples.

C, F2n++C0OH (n is an integer from 1 to 9), 01F
211+l S 03 H (m is an integer from 1 to 9),
Boron tetrafluoride, tetraphenylboron, hexafluorophosphoric acid, aromatic carboxylic acid, aromatic sulfonic acid.

Metal halides (zinc chloride, cadmium chloride, tin chloride)
etc.) The coupling components used in the present invention are those that form a dye by coupling with a diazo compound in a basic atmosphere, and include so-called active methylene compounds having a methylene group next to a carbonyl group, phenol derivatives, naphthol derivatives, etc. The following are specific examples:

Resorcin, phloroglucin, sodium 2,3-dihydroxynaphthalene-6-sulfonate, 1-hydroxy-2-naphthoic acid morpholinopropylamide, 1,5-
Dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,3-dihydroxy-6-sulfanylnaphthalene, 2-hydroxy-3-naphthoic acid morpholinopropyl 7mide, 2-hydroxy-3-naphthoic acid octylamide, 2-hydroxy-3 -Naphthoic acid 7nilide, benzoyl 7cetonylide, 1-phenyl-3-methyl-5
-pyrazolone, 1-(2,4,6-drichlorophenyl)-3-7nilino-5-pyrazolone, 2-(3-(
X-(2,5-di-tert-amylphenoxy)-butanamidobenzamide]phenol, 2,4-bis-
(benzoylacetamino)toluene, 1,3-bis-
(pivaloyl7cetaminomethyl)benzene These coupling components can be used alone or in combination of two or more, and any hue can be obtained as required.

As one of the color development aids of the present invention, it is preferable to add a basic substance as necessary for the purpose of making the system basic during thermal development and promoting the coupling reaction.

As these basic substances, used are sparingly water-soluble or water-insoluble basic substances, and substances that generate alkali upon heating.

Basic substances include inorganic and organic ammonium salts,
organic amines, amides, urea and thiourea and their derivatives,
Nitrogen-containing compounds such as thiazoles, virols, pyrimidines, piperazines, guanidines, indole necks, imidazoles, imidacillins, triazoles, morpholines, piperidines, 7midines, form 7midines, pyridines, etc. Examples include compounds. Two or more of these basic substances can be used in combination.

In addition, the coloring aids of the present invention include phenol derivatives, naphthol derivatives, flukoxy-substituted benzenes, alkoxy-substituted naphthalenes, hydroxy compounds, amide compounds, sulfonamide compounds can be added. These compounds are thought to lower the melting point of the coupling component or the basic substance, or to improve the thermal permeability of the microcapsule wall, resulting in a high color density.

The coloring aids of the present invention also include thermofusible substances.

The heat-melting substance is a substance having a melting point of 50°C to 150°C that is solid at room temperature and melts by heating, and is a substance that dissolves a diazo compound, a coupling component, or a basic substance. Specific examples of these compounds include fatty acid amides, N-substituted fatty acid amide, ketone compounds, urea compounds, esters, and the like.

Microcapsules containing the diazo compound of the present invention can be prepared, for example, by the method described in JP-A-59-190886. The polyurea and polyurethane that form the walls of the microcapsules can be obtained by polymerizing the corresponding monomers by the method described above, but the amount of monomer used is such that the average particle size of the microcapsules is 0.3μ to 12μ.
, the wall thickness is determined to be 0.01 to 0.3. Moreover, it is preferable to apply the diazo compound at 0.05 to 5.09/m2.

The microcapsules containing the diazo compound of the present invention are prepared by dissolving a diazonium salt and the same or different compounds that react with each other to produce a polymeric substance in a non-aqueous solvent having a boiling point of 406C or more and 95C or less at normal pressure. After dispersing and emulsifying the solution in a hydrophilic protective colloid solution, the temperature of the system is raised while reducing the pressure in the reaction vessel to distill off the non-aqueous solvent, move the wall-forming substance to the oil droplet surface, and remove heavy particles on the oil droplet surface. Substantially solvent-free microcapsules produced by forming a wall film through addition and polycondensation polymer production reactions are particularly preferred in terms of achieving a good shelf life.

In the present invention, the coupling component is 0.1 to 30 parts by weight and the basic substance is 0.1 to 30 parts by weight per 1 part by weight of the diazo compound.
．． It is preferable to use it in a proportion of 1 to 30 parts by weight.

The coupling component, basic substance, and other coloring aids used in the present invention are preferably used after being solidly dispersed together with a water-soluble polymer using a sand mill or the like. Preferred water-soluble polymers include water-soluble polymers used when preparing microcapsules (for example, Japanese Patent Application Laid-Open No. 1986-1999).
190886). In this case, the diazo compound, coupling component, and coloring aid are each added in an amount of 5 to 40% by weight based on the water-soluble polymer solution.

Preferably, the dispersed particle size is 10 microns or less.

A free radical generator (a compound that generates free radicals when irradiated with light) used in photopolymerizable compositions can be added to the copying material of the present invention for the purpose of reducing yellowing of the background after copying. . As free radical generators, aromatic ketones,
Examples include quinones, benzoin, benzoin ethers, 7zo compounds, organic disulfides, and acyloxime esters. The amount to be added is 1 part 1 part diazo compound.
0.01 to 5 parts by weight of the free radical generator.

Similarly, for the purpose of reducing yellowing, a polymerizable compound having an ethylenically unsaturated bond (hereinafter referred to as a vinyl monomer) can be used.

Vinyl monomers have at least one ethylenically unsaturated bond (vinyl group, vinylidene group, etc.) in their chemical structure.
It is a compound that has the chemical form of a monomer or a prepolymer. Examples thereof include unsaturated carboxylic acids and salts thereof, esters of unsaturated carboxylic acids and aliphatic polyhydric alcohols, amides of unsaturated carboxylic acids and aliphatic polyhydric amine compounds, and the like. The vinyl monomer is used in an amount of 0.2 to 20 parts by weight per 1 part by weight of the diazo compound.

It is preferable to use it by being contained in a microcapsule together with the free radical generator and the vinyl monomer 1-di and diazo compound.

In the present invention, in addition to the above materials, citric acid is used as an acid stabilizer.
Tartaric acid, oxalic acid, boric acid, phosphoric acid, pyrophosphoric acid, etc. can be added.

The copying material of the present invention is prepared by preparing a coating solution containing microcapsules containing a diazo compound, a coupling component, a basic substance, and other additives, and applying the coating solution onto a support such as paper or a synthetic resin film. The photosensitive layer is coated and dried by a coating method such as bar coating, blade coating, air knife coating, gravure coating, roll coating, spray coating, or dip coating to provide a photosensitive layer having a fraction of 2.5 to 3 (1+/m2).

The copying material of the present invention may have a laminated structure in which the microcapsules, coupling component, base, etc. may be contained in the same layer as described in the above method, or may be contained in separate layers. You can also do it.

It is also possible to provide an intermediate layer on the support as described in Japanese Patent Application No. 59-177669 and then apply a photosensitive layer.

As the support of the present invention, any paper support used for ordinary pressure-sensitive paper, thermal paper, dry or wet diazo copying paper, etc. can be used, as well as neutral sizing agents such as furkyl ketene dimer. Neutral paper with a pH of 6 to 9 (described in Japanese Patent Application No. 55-14281) sized by Paper with an optical surface roughness of 8μ or less and a thickness of 30 to 150μ as described in JP-A-58-136492, density 0.9c+/ as described in JP-A-58-69091 c.
m' or less and an optical contact ratio of 15% or more, Canadian Standard Freeness (JI) described in JP-A No. 58-69097.
The glossy side of the base paper made by the Yankee machine described in JP-A No. 58-65695 is used as the coated surface, and the color density and It is also possible to use paper that improves resolving power, such as paper that has been subjected to corona discharge treatment on the base paper described in JP-A No. 59-35985 to improve coating suitability.

Further, the synthetic resin film used as a support in the present invention can be arbitrarily selected from known materials that do not deform even when heated during the development process and have dimensional stability. Examples of such films include polyester films such as polyethylene terephthalate and polybutylene terephthalate, cellulose derivative films such as cellulose triacetate films, polystyrene films, polypropylene films, and polyolefin films such as polyethylene. Can be used. The thickness of the support is 20 to 200
μ is used.

The following method is preferred for forming an image on the copying material of the present invention. In the first step of performing exposure corresponding to the image of the original to form a latent image on the photosensitive layer and fixing areas other than the image forming area by light irradiation, various types of fluorescent lamps, xenon lamps, etc. can be used as the light source for exposure. Mercury lamps are used,
It is preferable that this emission spectrum substantially matches the absorption spectrum of the diazo compound used in the copying material, since areas other than the image forming area can be efficiently optically fixed.

Further, in the third step of heating and developing the entire surface of the photosensitive layer of the material using a heating means, the heating means may include a thermal pen, a thermal head, an infrared ray, a high frequency, a heat block,
A heat roller or the like can be used.

<Effects of the Invention> As detailed above, the copying material of the present invention has a good shelf life by containing a diazo compound in microcapsules, and also has a good shelf life for the copying material of the present invention. Between a first step in which a latent image is formed on the photosensitive layer by performing exposure corresponding to the above-mentioned photosensitive layer and the area other than the image forming area is fixed by light irradiation, and a third step in which development is performed by heating with a heating means. Low-temperature development is made possible by providing a second step of uniformly moistening the entire photosensitive layer of the copying material with water. The development temperature can be set arbitrarily depending on the characteristics of the material such as the diazo compound used and the development conditions, but the present invention has made it possible to freely select a development temperature of 150°C or less, which was previously impossible.

The heat development temperature of the present invention is determined by several factors, such as ensuring that the copy after development is completely dry, that curling is not large, and that the copying speed is fast, but is in the range of 60°C to 140°C. It is possible to set it to .

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples.

<Example> 3.45 parts of 1-morpholino-2,5-dibutoxybenzene-4 to diazonium hexafluorophosphate, xylylene diisocyanate and trimethylolpropane (3.45 parts)
: 1) 18 parts of the adduct were added to a mixed solvent of 6 parts of tricresyl phosphate and 5 parts of ethyl acetate, and dissolved by heating. This diazo compound solution was mixed with an aqueous solution containing 5.2 parts of polyvinyl alcohol dissolved in 58 parts of water, and emulsified and dispersed at 20°C to obtain an emulsion with an average particle size of 2.5 μm. Add 100 parts of water to the resulting emulsion and heat to 60°C while stirring.
After 2 hours, a capsule liquid containing a diazo compound in the core substance was obtained.

Next, 10 parts of 2-hydroxy-3-naphthoic acid anilide and 10 parts of triphenylguanidine were added to 200 parts of a 5% polyvinyl alcohol aqueous solution and dispersed in a punto mill for about 24 hours to obtain a dispersion with an average particle size of 3 μm.

To 50 parts of the capsule solution of the diazo compound obtained as described above, 50 parts of a dispersion of a coupling component and triphenylguanidine and 10 parts of a 40% calcium carbonate dispersion were added to prepare a coating liquid. Spread this coating solution on smooth high-quality paper (7
5q/m2) using a coating bar to dry weight 10
Copying material A was prepared by applying the coating to a coating film of c+/m2 and drying at 50°C for 1 minute.

A test manuscript (a circle with a diameter of 3 cm painted uniformly black with a 28 pencil on tracing vapor) was placed on copy material A and exposed to fluorescent light.

At this time, a fluorescent lamp whose emission spectrum has a maximum value at 420 nm was used. Next, an image was formed by heating for 3 seconds using a heat block heated to 120°C. Similarly, the temperature of the heat block was set to 80°C, i
It was also tested at oo°C.

On the other hand, after exposure and before heating, 29 parts m2 of water was applied to copying material A using a coating bar, and then heated using a heat block in the same manner. In addition, to test the shelf life, the samples were stored at 40° C. and 90% RH for 24 hours, exposed to light in the same manner, and developed at various temperatures. A 24 hour storage test was also conducted at 60°C and 30% RH. The densities of the colored parts and background parts of the samples obtained in each test were measured using a Macbeth densitometer. Table 1 shows the results of tests at different heating temperatures, and Table 2 shows the results of the pre-copy storage test.

As shown in Table 1, it can be seen that sufficient color density can be obtained even at low temperatures when developing in the presence of dampening water. When combined with the results shown in Table 2, the effects of the present invention become clear.

In the table, (*) indicates that the test was performed with dampening water, and (-) indicates that the test was conducted without dampening water.

Claims (1)

[Scope of Claims] 1) A copying material in which a heat-developable photosensitive layer containing a diazo compound, a coupling component, and a coloring aid is provided on a support, wherein the diazo compound is contained in microcapsules. A heat-developable copying material characterized by: 2) Thermal development according to claim 1, wherein the wall of the microcapsule is made of a polymer material formed by polymerization around the core material after emulsifying the core material of the microcapsule. Type copying material. 3) The heat-developable copying material according to claim 2, wherein the polymeric substance is formed of at least one selected from polyurethane and polyurea. 4) A first step of exposing the copying material according to claim 1 to light corresponding to the image of the original to form a latent image on the photosensitive layer and fixing the area other than the image forming area by light irradiation. , a second step of uniformly moistening the entire photosensitive layer of the copying material with moisture after the first step, and a third step of developing by heating with a heating means. Method.