JPH04177337A - Heat developing sensitive material - Google Patents

Abstract

PURPOSE:To improve overlapping of an exposed part and developing latitude by specifying the amount of weak acid strong base included in a polyvinyl alcohol used for a protective layer, in relation to the polyvinyl alcohol. CONSTITUTION:A heat developing sensitive material is composed of a sensitive halogenated silver formed on a supporting body, an organic silver salt, a heat developing sensitive layer including reducer and color toner, and of a protective layer primarily made of polyvinyl alcohol, formed on the sensitive layer. The amount of weak acid strong base included in the protective layer is not more than 0.2wt% in relation to the polyvinyl alcohol. The weak acid strong base is preferred to be sodium acetate. A heat developing sensitive material of broad heat developing latitude, and low level of overlapping of unexposed part of image, can thus be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a heat-developable photoreceptor using an organic silver salt. This invention relates to an 11-sex photoreceptor.

[Prior Art] Silver salt photography using silver halide is a widely used recording technique with excellent sensitivity and gradation. but,
After image exposure, processes such as development, stopping, and fixing are performed in a wet manner, which has caused problems in terms of workability, simplicity, stability, etc. In response to this, research was conducted on dry materials that eliminated these wet treatments, and
The contents are disclosed in Japanese Patent Publication No. 43-4924 and Japanese Patent Publication No. 43-4924. These use a catalytic amount of photosensitive silver halide and use a non-photosensitive organic silver salt as an image forming material. The mechanism by which organic silver salts function as image forming materials is said to be as follows.

That is, (1) a latent image is formed on the photosensitive silver halide by imagewise exposure. (2) The latent image acts as a catalyst, and when heated, an oxidation-reduction reaction occurs between the organic silver salt and the reducing agent, the organic silver salt is reduced to silver, and this becomes an image.

Such a heat-developable photoreceptor has a heat-developable photosensitive layer containing photosensitive silver halide, organic silver salt, reducing agent, color toning agent, etc. on a support, and the transparency of the photosensitive layer and its shelf life are improved. Generally, a protective layer is provided on the photosensitive layer in order to improve the properties, mechanical strength, etc. The thickness of the protective layer is suitably between 1 micron and 20 microns. If it is too thin, the above effects will be lost, and if it is too thick, there will be no special advantage and the cost will increase. Suitable polymers are preferably heat-resistant, colorless, and soluble in solvents, such as polyvinyl chloride, polyvinyl acetate, copolymers of vinyl chloride and vinyl acetate, and preferably 50 mol% vinyl chloride. above), polyvinyl butyral, polystyrene, polymethyl methacrylate, benzyl cellulose, ethyl cellulose, cellulose acetate butyrate,
Cellulose diacetate, cellulose triacetate, polyvinylidene chloride, chlorinated polypropylene, polyvinylpyrrolidene,
Examples include cellulose propionate, polyvinyl formal, cellulose acetate phthalate, polycarbonate, and cellulose acetate propionate. Further examples include gelatin derivatives such as seratin and phthalated seratin, acrylamide polymers, polyisobutylene, butadiene-styrene copolymers (any monomer ratio), polyvinyl-alcohol, and the like. Among these, cellulose derivatives and polyvinyl alcohol are particularly preferred polymers because they are water-soluble. However, cellulose derivatives have the disadvantage that they have high gas permeability and are easily desensitized during raw storage, and polyvinyl alcohol has the disadvantage that the thermal development latitude is narrow and fogging is likely to occur in unexposed areas of the image.

[Problems to be Solved by the Invention] The present invention was made in view of the above circumstances, and its purpose is to provide a heat-developable photoreceptor with less fog in unexposed areas of the image and a wide thermal development latitude. In particular, the present invention provides a heat-developable photoreceptor having a wide heat development latitude using polyvinyl alcohol as a protective layer.

[Means for Solving the Problems] In order to solve the above problems, the present inventors have conducted various studies on the problem of fogging in unexposed areas of images when polyvinyl alcohol is used as a protective layer, and as a result, the present inventors have found the following: Surprisingly, it has been discovered that the above problem can be solved by reducing the weak acid/strong base component in the polyvinyl alcohol forming the protective layer to 0.2% by weight or less based on the polyvinyl alcohol. To explain this further, polyvinyl alcohol is manufactured by saponifying polyvinyl acetate, so alkali is used in the manufacturing process, and this is hydrolyzed to form a salt with the acetate anion, containing weak acids and strong bases as impurities. ing. The inventors have discovered that when the content of this weak acid and strong base component is reduced to 0.2% by weight or less as mentioned above, the fog in the unexposed areas of the image is reduced and the development latitude is widened, leading to the completion of the present invention. It is something.

That is, the present invention provides a support, a heat-developable photosensitive layer containing a photosensitive silver halide, an organic silver salt, a reducing agent, and a toning agent formed on the support, and a main component formed on the photosensitive layer. A heat-developable photoreceptor having a protective layer made of polyvinyl alcohol, wherein a weak acid and strong base component contained in the protective layer is 0.2% by weight or less based on the polyvinyl alcohol, and the weak acid and strong base component is The base is sodium acetate.

The present invention will be explained in detail below.

The heat-developable photoreceptor according to the present invention has a heat-developable photosensitive layer formed on a support, and a protective layer made of polyvinyl alcohol laminated on the upper surface of the heat-developable photosensitive layer.

A wide variety of types of supports can be used in the present invention. Typical supports include cellulose nitrate film, cellulose ester film, poly(vinyl acetal) film, polystyrene film, poly(ethylene terephthalate) film, polycarbonate film, and glass, paper, metal, etc. is suitable when the support paper is hydrophilically treated and an organic solvent is used in the emulsion layer.

Paper sized with polysaccharides or the like is also suitable.

In the present invention, a heat-developable photosensitive layer is formed on one surface of the support, and the photosensitive silver halide used in the photosensitive layer of the present invention includes silver chloride, silver bromide, and chlorobromide. Silver, silver iodobromide, silver chloroiodobromide, etc. may be used, and these may be subjected to chemical sensitization or optical sensitization treatment as is applied to ordinary photographic emulsions. That is, as chemical sensitization, sulfur sensitization, noble metal sensitization, reduction sensitization, etc. can be used, and as optical sensitization, methods using conventionally well-known sensitizing dyes can be applied.

Sensitizing dyes include cyanine dyes, merocyanine dyes,
Trinuclear dyes are preferably used, for example, 3.3'-
Dicarboxyethyl-2,2°-thiacarbocyanine iodide, 3,3°-diethyl-2.2′-thiacarbocyanine iodide, 3,3°-disulfoethyl-
2,2°-thiadicarbocyanine promite, 3.3'
-diethyl-2,2'-thiatricarbocyanine iodide and the like.

Furthermore, the halogen composition within the particles may be uniform or may have a different multilayer structure. Two or more types of silver halides having different halogen compositions, grain sizes, grain size distributions, etc. may be used in combination.

The organic silver salts used in the medium of the present invention include "Fundamentals of Photographic Optics" (1st edition, published in 1982), non-silver salt edition, p.
47, organic silver salts and triazole silver salts described in JP-A-59-55429, etc., and it is preferable to use silver salts with low photosensitivity. Examples include silver salts of aliphatic carboxylic acids, aromatic carboxylic acids, thiocarbonyl compounds having a mercapto group or a-hydrogen, and imino group-containing compounds.

Aliphatic carboxylic acids include acetic acid, butyric acid, succinic acid, sebacic acid, adipic acid, oleic acid, linoleic acid, linoleic acid, tartaric acid, valmitic acid, stearic acid, behenic acid, camphoric acid, etc. Silver salts with a small number of carbon atoms are unstable, so those having an appropriate number of carbon atoms (for example, those in the range of 16 to 26 carbon atoms) are preferred.

Examples of aromatic carboxylic acids include benzoic acid derivatives, quinolinic acid derivatives, naphthalenecarboxylic acid derivatives, salicylic acid derivatives, gallic acid, tannic acid, phthalic acid, phenylacetic acid derivatives, and pyromellitic acid.

Examples of compounds having a mercapto or thiocarbonyl group include 3-mercapto-4-phenyl-1,2,4-1-
Riazole, 2-mercaptobenzimidazole, 2-
Mercapto-5-aminothiadiazole, 2-mercaptobenzothiazole, S-alkylthioglycolic acid (
Alkyl group with 12 to 22 carbon atoms), dithiocarboxylic acids such as dithioacetic acid, thioamides such as thiostearamide,
5-carboxy-1-methyl-2-phenyl-4-thiopyridine, mercaptotriazine, 2-mercaptobenzoxazole, mercaptooxadiazole or 3-
Examples include amino-5-benzylthio-1,2,4-triazole and mercapto compounds described in US Pat. No. 4,123,274.

As a compound containing an imino group, Japanese Patent Publication No. 44-302
70 or 45-18416 or its derivatives, such as alkyl-substituted benzotriazoles such as hensitriazole and methylbenzotriazole, halogen-substituted benzotriazoles such as 5-chlorobenzotriazole, butylcarboimidobenzo Carboimidhencytriazoles such as triazole, nitrobenzotriazoles described in JP-A-58-118639, sulfobenzotriazole, carboxybenzotriazole or its salt, or hydroxybenzotriazole as described in JP-A-58-115638, etc. 1,2,4-triazole and IH-tetrazole described in U.S. Pat. No. 4,220,709,
Representative examples include carbazole, saccharin, imidazole and derivatives thereof.

The reducing agent used in the present invention is one that is capable of reducing an organic silver salt to produce silver when heated in the presence of exposed photosensitive silver halide. The reducing agent can be appropriately selected and used depending on the type of organic silver salt used. Such reducing agents include, for example, monophenols, bisphenols, trisphenols, tetrakisphenols, mononaphthols, bisnaphthols, dihydroxynaphthalenes, trihydroxynaphthalenes, dihydroxybenzenes, trihydroxybenzenes. , tetrahydroxybenzenes, hydroxyalkyl monoethers, ascorbic acids, 3-pyrazolidones, pyrazolones, pyrazolines, sugars, phenylenediamines, hydroxyamines, reductones, hydroxamines, hydrazines, hydrazides, These include acidoximes and N-hydroxyureas.

Among these reducing agents, 1,1-bis(2-hydroxy-3,5-dimethylphenyl)-3,5 is a specific example of a reducing agent that can be preferably used when fatty acid silver is used as the organic silver salt. , 5-trimethylhexane,
1.1-bis(2-hydroxy-3-tert-butyl-5-methylphenyl)methane, 1.1-bis(2-hydroxy-3,5-di-tert-butylphenyl)
Methane, 2,6-bis(2-hydroxy-3-tert
-butyl-5-methylphenyl)-4-methylphenol, 6,5°-benzylidene bis(2,4-diter)
t-butylphenol), 4.4°-methylenebis(2
, 6-di-t-butylphenol), 2.6-di-t-
Butyl-4-(3°,5°-dimethyl-4°-hydroxypencyl)phenol, 2,6-sheet t-butyl-4
-(3°,5°-diethyl-4′-hydroxybenzyl)phenol, 6.6°-benzylidene bis(2-te
rt-butyl-4-methylphenol), 6,6''-benzylidenebis(2,4-dimethylphenol), 1.
1-bis(2-hydroxy-3,5-dimethylphenyl)-2-methylpropane, 1,1,5.5-tetrakis(2-hydroxy-3,5-dimethylphenyl)-2,
4-diethylpentane, 2.2-methylenebis(4-methyl-6-t-butylphenol), 2.2-methylenebis(4-ethyl-6-t-butylphenol), 2
．． 2-bis(4-hydroxy-3-methyl-5-ter
t-butylphenyl)propane, 2,2°-bis(4-
hydroxy-3,5-di-tert-butylphenyl)
Propane, 2.2°-dihydroxy-1,1'-binaphthyl, 6.6'-dibromo-2,2'-dihydroxy-
1,1°-binaphthyl, 6,6゛-dinitro-2,2°
-dihydroxy-1,1′-binaphthyl, bis(2-hydroxy-1-naphthyl)methane, 4.4°-dimethoxy-1,1°-dihydroxy-2,2′-binaphthyl,
Examples include 4-sulfonamidophenol, 2-benzenesulfonamidophenol, and 2,6-dichloro-4-benzenesulfonamidophenol.

Specific examples of reducing agents that can be preferably used when benzotriazole silver salts are used as organic silver salts include:
l-phenyl-3-pyrazolidones, ascorbic acid,
Examples include monocarboxylic acid esters of ascorbic acid and naphthols represented by 4-methoxy-1-naphthol. Specific examples of reducing agents that can be preferably used for silver behenate include O-bisphenols and hydroquinones having a bis(hydroxyphenyl)methane structure.

Color toning agents are used when it is desired to blacken the silver produced by reduction.2 Effective color toning agents depend on the organic silver salt and reducing agent used, but the most common color toning agents include phthalazinones, oxazinediones, Cyclic imides, urazoles, 2-pyrazolin-5-ones, quinazolines, N-
Examples include hydroxynaphthalimides, uracils, phthalazinediones, and thiazolidinediones.

In addition to this, it is preferable to contain an appropriate binder for the purpose of improving the monodispersity of film properties.

Examples of binders include cellulose esters such as nitrocellulose, cellulose phosphate, cellulose sulfate, cellulose acetate, cellulose propionate, cellulose butyrate, cellulose myristate, cellulose palmitate, cellulose acetate/propionate, cellulose acetate/butyrate, and methylcellulose. , cellulose ethers such as ethyl cellulose, propyl cellulose, butyl cellulose, polystyrene, polyvinyl chloride, polyvinyl acetate, polyvinyl butyral, polyvinyl acetal,
Vinyl resins such as polyvinyl alcohol and polyvinylpyrrolidone, copolymer resins such as styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-butadiene-acrylonitrile copolymer, vinyl chloride-vinyl acetate copolymer, polymethyl methacrylate, polymethyl acrylate, Acrylic resins such as polybutyl acrylate, polyacrylic acid, polymethacrylic acid, polyacrylamide, polyacrylonitrile, polyesters such as polyethylene terephthalate, poly(4,4-isopropylidene-diphenylene-co-1,4-cyclohexylene dimethylene) carbonate)
, poly(ethylenedioxy-3,3'-phenylene thiocarbonate), poly(4,4°-isobropylidene diphenylene carbonate coated terephthalate), poly(4,4°-isopropylidene diphenylene carbonate), poly (4,4'-5ec-butylidene diphenylene carbonate), polyacrylate resins such as poly(4,4°-isopropylidene diphenylene carbonate block-oxyethylene), polyamides, polyimides, epoxy resins , phenolic resins, polyolefins such as polyethylene, polypropylene, and chlorinated polyethylene, and natural polymers such as seratin.

In addition, an antifouling agent, an alkali generator, and the like may be added to the photosensitive layer, if necessary.

The preferred blending ratio of the above components in the photosensitive layer of the present invention is as follows.

The amount of organic silver salt used is 0.3-30 g7m2,
Especially 0.7 to 15 g/m2, and even 1.2 to 8 g/m
2 is preferred.

Also, preferably 0.01 to 2 mol, more preferably 0.05 mol of photosensitive silver halide per 1 mol of organic silver salt.
It is desirable to contain up to 0.4 mol. Further, the reducing agent is preferably 0.05 to 3 mol per mol of the organic silver salt,
More preferably, it is contained in an amount of 0.2 to 1.3 moles.

The amount of toning agent used ranges from about 0.0001 mole to about 2 moles, preferably from about 0.0005 moles to about 1 mole, per mole of organic silver salt.

Note that the photosensitive layer may be formed in a multilayer structure.

The heat-developable photosensitive layer can be applied by a variety of coating methods, including dipping, air knife, curtain coating, and hopper coating as described in U.S. Pat. No. 2,681,294. There is an extrusion coating method using Two or more layers can be formed simultaneously if desired.

In the present invention, a protective layer made of polyvinyl alcohol is further formed on the heat-developable photosensitive layer constructed as described above. 0.2% by weight or less.

Methods for removing weak acid and strong base components include a method of washing polyvinyl alcohol powder with methanol, ethanol, etc., and a method of repeatedly removing the component by reprecipitation.

In addition, as a method for quantifying the weak acid and strong base component, there is a method of dissolving polyvinyl alcohol in water and measuring the content by titrating using a suitable indicator such as methyl orange.

The protective layer can be formed by the same method as the method for forming the heat-developable photosensitive layer.

The thickness of the protective layer is preferably 0.5 to 4 μm.

The heat-developable photoreceptor according to the present invention produced by the above method can further be provided with an antistatic layer or a conductive layer.

Antihalation substances and antihalation dyes may also be included.

If desired, the heat-developable photosensitive layer may further contain a matting agent such as starch, titanium dioxide, zinc oxide, or silica. Further, optical brighteners 1 such as stilbenes, triazines, oxazoles, and coumarin optical brighteners may be included.

The heat-developable photoreceptor of the present invention is exposed to a light source such as a xenon lamp, tungsten lamp, mercury lamp, laser, or LED array, and then developed simply by heating the photoreceptor. The heating temperature is suitably 100°C to 160°C, more preferably 110°C to 140°C. Higher or lower temperatures within the above ranges can be used by lengthening or shortening the heating time. Development time is usually about 1 second to 60 seconds.

There are various methods for heat developing the photoreceptor of the present invention.
For example, the photoreceptor may be brought into contact with a simple heating plate, a heated drum, or in some cases passed through a heated space, or heated with high frequency heating or a laser beam. You may.

[Example 1 Hereinafter, the present invention will be specifically explained with reference to Examples.

Stream side 1, 2, (1) A dispersion having the following composition was prepared using a homomixer under safe light.

Polyvinyl butyral -3.0 parts Silver behenate -2.5 parts Silver bromide -0.5 parts Behenic acid -1.0 parts Azelaic acid -0.3 parts Phthalazinone -・0.5 part 2.2
'-Methylenebis(4-methyl...1.9 parts-6-
(t-butylphenol) xylene...-30 parts n-
Butanol...30 parts Using this dispersion, polyethylene terephthalate (PET)
) A photosensitive layer was provided on the film to have a dry film thickness of 10 μm, and a protective layer with a dry film thickness of 2 μm was coated on the film using polyvinyl alcohol with different contents of sodium acetate listed in Table 1. I got a body.

These photoreceptors were exposed to a mask using a tungsten lamp at an intensity of 10,001 ux for 10 seconds. The optical density of the exposed area and the optical density (fog) of the unexposed area as a result of thermal development under the conditions listed in Table 1 are listed in Table 16 Table 1 The content of acetic acid sorter, which is a weak acid and strong base, is 0. .20% by weight
The following photoreceptor (Example 1.2) did not cause fogging even when developed under high temperature conditions, and a clear image could be obtained.

3.4, Proportion 2 In Example 1, 1.9 parts of 2.2°-methylenebis(4-methyl-6-t-butylphenol) was replaced with 2.6-di-t-butyl-4-(3,5-dimethyl -4-hydroxybenzyl)phenol 1.9 parts, the film thickness of the photosensitive layer is 1
A photoreceptor was obtained in the same manner as in Example 1 except that 4μ was used.

The results are listed in Table 2.

Table 2 For the OD in Table 2, the value at 400 nm measured with a spectrophotometer was used.

In Example 1, the protective layer contained 54.9% by weight of polyvinyl alcohol, a pH of 4 or less, and a particle size of 10 to 20 nm.
m 20% dispersion of colloidal silica, 45% by weight of water, impurity sodium acetate 0.2% with respect to polyvinyl alcohol.
A photoreceptor was produced in the same manner as in Example 1 except that 0% by weight was used.

When evaluated in the same manner as in Example 1, there was no difference in performance from photoreceptor 1 on the actual flow side, and clear images without fog were obtained even under heat development conditions of 1.25° C. for 10 seconds.

[Effects of the Invention] In the present invention, the content of weak acid and strong base in the polyvinyl alcohol used for the protective layer is set to 0.2% by weight or less based on the polyvinyl alcohol, thereby improving fog in unexposed areas of the image and development latitude. It was possible to obtain a heat-developable photoreceptor.

Patent applicant Oriental Photo Industry Co., Ltd. Canon Co., Ltd. Patent attorney Tadashi Wakabayashi

Claims (1)

[Scope of Claims] 1. A support, a heat-developable photosensitive layer containing a photosensitive silver halide, an organic silver salt, a reducing agent, and a toning agent formed on the support, and a heat-developable photosensitive layer formed on the photosensitive layer. A heat-developable photoreceptor having a protective layer whose main component is polyvinyl alcohol, characterized in that a weak acid/strong base component contained in the protective layer is 0.2% by weight or less based on the polyvinyl alcohol. A heat-developable photoreceptor. 2. The heat-developable photoreceptor according to claim 1, wherein the weak acid and strong base is sodium acetate.