JPH0414036A - Direct positive silver halide photographic sensitive material - Google Patents

Abstract

PURPOSE:To enhance contrast of the direct positive photosensitive material and maximum density and to regulate minimum density to a sufficiently low value by incorporating a specified compound. CONSTITUTION:This photosensitive material is provided on a support with at least one prefogged direct positive silver halide emulsion layer and this layer or its adjacent hydrophilic colloidal layer contains at least one kind of the compound represented by formula I in which each of R1 and R2 is H, alkyl, alkoxy, or the like, and the compound can be embodied by formula II and the like.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a pre-fogged direct positive silver halide photographic material, and more particularly to a direct positive silver halide photographic material that exhibits improved photographic properties. This invention relates to silver halide photographic materials.

(Prior Art) Direct positive silver halide photographic light-sensitive materials are often used mainly in the printing industry for the "turning" process in the photolithography process.

In this "returning" process, the original original image is reproduced from a positive image to a positive image or from a negative image to a negative image, but the important point in this process is to faithfully reproduce the fine lines and halftone dot images of the original image. required.

The photographic properties of the direct positive silver halide emulsion used to meet these requirements are that the tone is high (particularly high contrast in the toe area), the maximum density (Dmax) is high, and the minimum density (Dm
ir)) is required to be low.

Generally, the emulsions used in direct-positive silver halide photosensitive materials are thick (divided into two types. One type contains an electron-trapping compound that is said to trap electrons inside the silver halide grains. It is a type of emulsion consisting of silver halide grains whose surfaces are prefogged and which directly reverses itself.

The other type of emulsion is one in which the electron-trapping compound is not formed inside the silver halide grains, but the grain surfaces are fogged, and the emulsion is reversed only by the addition of an organic desensitizer.

The former emulsion is disclosed in US Patent No. 3. 367, 778
, 3,632.340, etc.

In this patent, a core emulsion is made in advance, and the core emulsion is
The shell was coated by chemical sensitization treatment such as sulfur sensitization, gold sensitization, reduction sensitization, and treatment with metals belonging to Group 8 of the periodic table (rhodium, palladium, iridium, othnius, platinum, ruthenium, etc.) A method is described in which the surface of the shell is then fogged to directly produce a positive reversal emulsion.

Further, when a metal belonging to Group 8 of the periodic table is used as an electron trapping compound, a method of adding the metal at the time of silver halide precipitation when preparing an emulsion is also a known technique.

The latter emulsion is disclosed, for example, in US Pat. No. 1,186.
No. 717, No. 1,186,714, No. 1.1.86,
No. 716, U.S. Pat. No. 3,501. .

No. 306, 3,501. , No. 307, 3. No. 501゜310, No. 3,531,288, etc., and organic desensitizers include, for example, U.S. Pat. No. 2,669.
．． Nitrostyryl type compounds described in No. 515, pinacryptol yellow, 5-meth, nitrobenzylidene rhodanine, etc., bis-pyridinium compounds described in Japanese Patent Publication No. 481-3059, phenazine compounds described in Japanese Patent Publication No. 47-8746, etc. Are known.

However, the reversal emulsions produced by these methods do not always produce a good reversal image, and the reversal image may have a soft tone or a high Dmjn. In particular, it is currently difficult to obtain sufficient quality required for direct positive silver halide photographic materials used in the "returning" process in the photolithography process in the printing industry.

(Objective of the Invention) The object of the present invention is to achieve a high maximum density (Dmax) with a high tone (particularly high contrast in the foot part), and a high minimum density (Dmin).
) is to provide a silver halide photographic material for direct positive use which is sufficiently low.

(Structure of the Invention) The object of the present invention is to comprise at least one pre-fogged direct positive silver halide emulsion layer on a support, and in the emulsion layer or an adjacent hydrophilic colloid layer, the following general Formula (1) As the alkyl group of R1 and R2, methyl group, ethyl group, n-propyl group, n-butyl group, t-butyl group, n-
Examples include pentyl group and n-hexyl group, hydroxyalkyl groups include hydroxymethyl group and hydroxylethyl group, and alkoxy groups include methoxy group and ethoxy group.

Specific examples of compounds used in the present invention are shown below, but the invention is not limited thereto.

-N (wherein R and R2 represent a hydrogen atom, an alkyl group, a hydroxyalkyl group, or an alkoxy group.

However, R5 and R2 are never hydrogen atoms at the same time. ) -N -N -N N -N N-N -N The compound represented by the general formula (I) is preferably contained in an amount of IXl, O-' to 5X10-' mol per mol of silver halide, In particular, a preferable addition amount is in the range of lXl0-5 to 2 x 10-2 mol.

The compound represented by general formula (I) can be prepared in an aqueous solution or
As a solution in a water-miscible organic solvent such as alcohols such as methanol and ethanol, esters such as ethyl acetate, and ketones such as acetone, it can be used as a direct positive silver halide emulsion solution or for its adjacent layer. It can be added to a hydrophilic colloid solution. When added to the emulsion solution, it can be added at any time before coating, but it is particularly preferable to add it to the coating solution prepared for coating.

The hydrophilic colloid layer adjacent to the direct positive silver halide emulsion layer is located between the support and the emulsion layer. For example, it is an undercoat or subbing layer, which is located outside the emulsion layer from the support. For example, an intermediate layer or a protective layer can be mentioned.

Generally, in silver halide photographic materials, Dmi
It is an essential condition that n is low. To this end, many techniques have been proposed to date. In particular, it is well known that it is useful to add organic compounds called stabilizers or antifoggants to emulsions, and typical compounds include thihydroxy-6-methyl-L 3,3
a, 7-chitrazaindene, benzotriazole, 6-
Nidropenzimidazole, 2-mercaptobenzothiazole, 1-phenyl-5-mercaptotetrazole, and the like are known.

However, the effects of these compounds depend on the silver halide composition of the emulsion, the type and degree of chemical ripening, and the type and amount of coexisting spectral sensitizing dyes. It is not uniform due to differences. moreover,
Even if it shows the same overall effect on negative emulsions, although the effect may be different, it does not necessarily show the same effect on direct positive silver halide emulsions. Furthermore, it is not possible to easily predict the influence of the pre-fogged direct positive silver halide emulsion used in the present invention. In fact, an attempt was made to lower Dmin using 1-phenyl-5-mercaptotetrazole, but the effect was not sufficient, and other problems occurred in photographic performance. By using a compound in which R1 and R2 are limited substituents as described above, a pre-fogged direct positive silver halide photographic light-sensitive material with sufficiently low Dmin without affecting other photographic properties can be obtained. I was able to get

Silver halides used in the present invention include silver chloride, silver bromide,
Silver chlorobromide, silver chloroiodide, or silver bromoiodide are used. These silver halides are produced by various methods, such as a neutral method, an ammonia method, and an acid method. Particle size is 0.05μ
-1μ is used, preferably 0.1μ to 0.5μ.

Further, the particle shape may be a regular crystal such as a cube or an octahedron, or an irregular shape such as a spherical or plate shape, but the particle size distribution is preferably monodisperse.

Recently, direct positive silver halide photosensitive materials for bright rooms, which are exposed using ultraviolet-rich light sources such as xenon, metal halide, mercury lamps, and ultra-high-pressure mercury lamps, and are handled under ultraviolet-cut fluorescent lamps, have been widely used. It is becoming more and more common.

The direct positive silver halide photographic light-sensitive material of the present invention can be the above-mentioned bright room light-sensitive material. It has the advantage of being much easier to work with since it can be handled in a bright room compared to the photosensitive materials that were handled in a dark room in Jubei.

Such sensitive materials for use in bright rooms are required to have good safelight properties under fluorescent lamps that block ultraviolet rays. As a direct positive silver halide emulsion for bright room use, the grain size is 0.
．． The thickness is preferably 3μ or less.

As mentioned above, the direct positive silver halide emulsions used in the present invention are generally classified into two types.

This type has an electron-trapping compound that is said to trap electrons inside one of the silver halide grains. A center that generates a latent image, that is, a center that becomes a nucleus for generating a latent image, and that center also acts as an electron acceptor. These compounds include U.S. Pat. No. 448,467, U.S. Pat. 632
．． Examples include rhodium, palladium, iridium, platinum, osmium, and ruthenium, which belong to Group 8 of the periodic table and are listed in No. 340. It is also useful to chemically sensitize the center (core) of silver halide grains (for example, gold sensitization, sulfur sensitization, reduction sensitization, and sensitization methods that combine these).

These compounds may be added at the time of precipitation of silver halide, or after grain formation, these compounds may be added to the surface of the grain using the grain as a core, and/or after chemical sensitization, the grain may be added. A silver halide shell may be coated on top. These compounds can be added in the form of metal salts as an aqueous solution, and the amount added is approximately 1X10-7 to 1X10-3 mol per 1 mol of silver halide. In addition, if chemical sensitization is performed, for example,
If it is based on a gold compound and a thiosulfate, the amount of gold compound is 3 x 10-7 to 4 x per mol of silver halide in the core emulsion.
The amount added is preferably 10-5 mol, and the amount of thiosulfate added is in the range of 3 x 10 to 3 x 10-' mol.

Aging temperature is 40-70℃, pH is 4-10, time is 30℃.
It may be carried out for ~120 minutes. These conditions may be appropriately selected depending on desired photographic characteristics. Further, the silver halide grains may have a two-layer or more multilayer structure, such as a so-called core/shell structure, or may have a uniform single-layer structure. It is also possible to change the halogen composition between the core and shell.

Another type of organic desensitizer that is used is one that is reversed only by the addition of the organic desensitizer, and is characterized by its polarographic half-wave potential, that is, its redox potential determined by polarography. Organic desensitizers useful in the present invention are those in which the sum of polarographic anode potential and polarographic cathode potential is positive. Methods for measuring these redox potentials are described, for example, in US Pat. No. 3,501,307.

A particularly effective organic desensitizer used in the present invention is the imidazo(4,5-b)quinoxaline cyanine dye described in Belgian Patent No. 660,253. Another particularly effective organic desensitizer is U.S. Pat.
．． This is an indole cyanine dye having an aromatic substitution at the 2-position and is described in specifications such as No. 314.796 and No. 3,505.070.

Yet another example of an effective organic desensitizer is U.S. Pat.
No. 01,310, No. 4,097,285, No. 4,
No. 259,439 and other specifications. However, it goes without saying that the invention is not limited to these. Specific examples of organic desensitizers used in the present invention include:
1.1'-dimethyl-2,2'-diphenyl-3,3'
-introcarbocyanine bromide, 2,2--dyl-methoxyphenyl-1,1'-dimethyl-3,3'
-Indolocarbocyanine bromide, 1.1゛-dimethyl-2,2-,8-1riphenyl 3.3--indolocarboxyanine verchlorate, ■,3-diaryl-2- (2-(9methyl -3-carbazolyl)vinyl]imidazo(4,5-b)quinoxaline p-1 luenesulfonate, 1,3-diethyl-1--2-phenyl imidazo(4,5-b)quinoxarif-3- −
Indolocarbocyanine iodide, 1.1″, 3
．． 3--Tetraethylimidazo[4゜5-b]quinoxalinolupocyanine φ chloride, 1. 1. -3.
3--Tetramethyl-2-phenyl-3-indropyrrolo[2,:3-b) pyridocarbocyanine iodide, 1.1-. 3゜3.3-. 3-hexamethylpyrrolo(2,3-b)pyridocarbocyanine verchlorate, 1°1"3.3-tetramethyl-5-nitro-
2'phenylindo-3'-indocarbocyanine iodide, 1.1-. 3,3.3”, 3-hexamethyl-5,5′-dinitroindocarbocyanine-・p-
Toluenesulfonate, 3'-ethyl-1-methyl-2
-Phenyl-6'-nitro3-indrothiarufocyanine, p-1 luenesulfonate, pinacryptol,
Yellow 5-m-nitrobenzylidene rhodanine, 5-
m-nitrobenzylidene-3-phenylrhodanine, 1.
Examples include iodine compounds such as 3-diethyl-6-nitrothia-2-monocyanine iodide.

The organic desensitizer is used in an amount of 0.2 to 2.0% per mole of silver halide.
It is used at concentrations in the range of 0g.

The provision of fog nuclei to the surface of silver halide grains carried out in the present invention is described in U.S. Pat.
, 340, 3,501,305, Japanese Patent Publication No. 50-681
Fogging can be carried out using a known method such as using a reducing agent alone or a reducing agent and a gold compound, or using light, as described in No. 33.

Particularly suitable is the combination of a reducing agent and a gold compound. The fogging conditions may be varied depending on the desired photographic properties, but generally the pH is in the range of 4 to 10, the temperature is in the range of 40 to 80°C, and the PAg is in the range of 4 to 9.

As the reducing agent, aldehydes such as formalin, hydrazine, triethylenetetramine, thiourea dioxide, stannous chloride, amine borane, etc. are used.

The amount of reducing agent used is 1 mole of silver genide.
x10-S to 2X10-2 moles are preferred.

Gold compounds are monovalent and trivalent water-soluble gold salts, such as chloroauric acid, gold thiocyanate, sodium chloroaurate, potassium aurate, potassium chloroaurate, potassium bromoaurate, potassium iodoaurate, and potassium gold cyanide. , potassium gold thiocyanide, sodium gold thiomaleate, gold thioglycose, etc. are used. The amount used is preferably 3.times.10@-7 to 5.times.10@-5 mol per mol of silver halide.

As the protective colloid and binder for the silver halide grains used in the practice of the present invention, as well as the binder for the adjacent hydrophilic colloid layer, gelatin is most preferable, but polymeric compounds other than gelatin (for example, polyvinyl alcohol ,
Cellulose derivatives such as polyvinylpyrrolidone, polyacrylamide, polyacrylic acid, polyvinylimidazole, polyethylene glycol, maleic anhydride, polystyrene sulfonic acid, polyvinylpyridine, methylcellulose, hydroxymethylcellulose, carboxymethylcellulose, etc., and copolymers of these monomers, etc.) Part or all of the gelatin can be replaced. The gelatin used is alkali-treated gelatin, acid-treated gelatin (isoionic point 5 to 9), enzyme-treated gelatin, low calcium content gelatin (content IQQPPM or less), high jelly strength gelatin (PAGI method jelly strength 270 or more), gelatin Derivatives (for example, chemically modified gelatin such as phthalated gelatin and carbamylated gelatin) are used.

Also, to improve dimensional stability as part of the binder,
Polymer latex can be used. Examples of the polymer latex include polyacrylic acid types such as polyvinyl acetate, polymethyl acrylate, ethyl, and butyl, polymethacrylic acid types such as polymethyl methacrylate, ethyl, and butyl, polystyrene types, polybutadiene types, and the like. There are copolymers of monomers, etc. The particle size and physical properties such as glass transition point of the polymer latex are not particularly limited, but the particle size is preferably 1 μm or less, or less.

Dyes with absorption wavelengths between 400 nm and 700 nm can be used in the practice of this invention.

These dyes can be added to emulsion layers, protective layers, interlayers, subbing layers, and backing layers. In particular, in direct positive silver halide photosensitive materials for bright rooms, it is necessary to reduce or cut the photosensitivity of silver halide in the visible light region in order to improve safelight properties in bright rooms, and to increase absorption maximum. 400～
It is desirable to use a dye having a wavelength of 550 nm, which is eluted during the development of the photosensitive material, or whose color is erased by alkali, reducing agent, etc. in the processing solution. Examples of these dyes include oxonol dyes, azo dyes, benzylidene dyes, merocyanine dyes, styryl dyes, and quinoline dyes. 59-154439, 58-176635
, 58-215643, 52-20822, 49
-5616 shows a dye having an absorption maximum between 400 and 700 nm.

The amount used in each layer (e.g. protective layer, backing layer, etc.)
So IT? 0.02-0.3g per serving, preferably 0.05
It can be used in the range of ~0.2g.

Spectral sensitizers may be used in the practice of this invention.

Spectral sensitizing dyes include known dyes such as dimethine dyes, trimethine cyanine dyes, halogen-substituted hydroxyphthalein dyes, phenazine dyes, benzothiazole, cyanine dyes containing a benzoselenazole nucleus, cyanine dyes containing a naphthoxazole nucleus, and trimethine dyes. Phenylmethane dyes, cyanine dyes containing indolenine nuclei, cyanine dyes containing thiazole nuclei, etc. can be used.

Known additives can be added to the direct positive silver halide photographic light-sensitive material of the present invention. Stabilizers include mercapto compounds, benzotriazole compounds, oxazole compounds, etc. Hardeners are not particularly limited, but include aldehyde compounds, 2-hydroxy-4,6-dichloro-1,
3,5) riazine, N-methylol compounds, vinyl sulfone compounds, coating aids include saponin, alkylene oxide type, glycidol type nonionic surfactants, carboxylic acid, sulfonic acid, phosphoric acid, sulfuric acid ester groups,
anionic activators containing acidic groups such as phosphate ester groups;
Ampholytic surfactants such as amino acids and aminosulfonic acids,
Polyalkylene oxide compounds are used.

Supports used in the practice of the present invention include, for example, glass,
Film bases such as cellulose acetate, polyethylene terephthalate, baryta paper, resin coated paper, aluminum foil, concrete, etc. can be used.

The direct positive silver halide photographic light-sensitive material of the present invention may further contain a brightening agent, an ultraviolet absorber, a matting agent, an antistatic agent, and the like, if necessary.

The direct positive silver halide photographic light-sensitive material of the present invention can be processed under various conditions, such as 30-50°C, 20-60°C.
Processes such as high-temperature rapid automatic processor processing in seconds and dexterous image processing are not particularly limited.

As the developer, either a developer used for general silver halide photographic light-sensitive materials or a Lith developer can be used.

The present invention will be explained in more detail with reference to Examples below, but the embodiments of the present invention are not limited thereto.

(Example) Example 1 A 2N potassium bromide aqueous solution containing 6 mol% sodium chloride and a silver nitrate aqueous solution of the same concentration were added to a gelatin aqueous solution kept at 50°C for 15 minutes using a controlled double jet method to form a core emulsion. adjusted. Subsequently, 70 mg of sodium thiosulfate and 7 μg of chloroauric acid were added as an aqueous solution to 1 kg of silver halide (converted to silver nitrate),
Chemical aging was performed at 50°C for 70 minutes. Further, the same halogen and silver nitrate aqueous solutions used for mixing the core emulsion were mixed for 110 minutes to prepare a core/shell type emulsion in which the core was chemically sensitized.

This emulsion was demineralized and washed with water by the flocculation method, and then an aqueous solution of inert gelatin was added and redissolved at 40°C. The average grain size of these silver halide grains is 0.13μ
Met.

To the redissolved emulsion, 150 mg of thiourea dioxide and 2 mtz of chloroauric acid were added to 1 kg of silver nitrate as an aqueous solution, and heated under I'H6, 60°C for 70 minutes to fog the surface of the silver halide grains. I set it.

This emulsion was divided, no additives were added, the comparative compound shown below and the exemplified compound represented by general formula (1) were added, and 2-hydroxy-4,6-dichloro-1,3 was added as a hardening agent. , 5-triazine and a suitable amount of sodium lauryl sulfonate as a surfactant were added, and the mixture was coated on a polyethylene terephthalate film base having a thickness of 100 μm in an amount of silver nitrate of 5 g per 1 d. At the same time, as a protective layer, a gelatin solution containing a yellow dye having the following structural formula (80 mg per lrrr) was simultaneously coated in an amount of 1 g per 1 gelatin.

Yellow Dye So, Na So, Na The polyethylene terephthalate film base used was coated in advance with a gelatin backing layer containing 100 mg of the above yellow dye per 1 d. The coated sample was heated at 50° C. for 4 days and then subjected to sensitometry.

Exposure was carried out using a bright room printer (Dainippon Screen P-627 printer) through a sensitometry light wedge.
Count exposure. It was developed for 30 seconds at 38° C. with a developer having the composition shown below, followed by fixing, washing with water, and drying.

Developer formulation Hydroquinone 35.0g Phenidone 0.2g Sodium hydroxide 12g Potassium triphosphate
83g sodium sulfite
65g ethynediaminetetraacetic acid disodium 1.5g3-
Diethyl-amino-1,2-propanediol 15g 5-methylbenzotriazole 0.3g Sodium bromide
Add 1.7g water to make II. (PHIl, 6
) The developed sample was prepared using Macbeth Transmission Density Clock (RD917
The transmission density was measured using a mold) and the photographic characteristics were calculated. The results are shown in Table-1.

Comparative compound -N -N -N (blank below) Example 2 A 2N potassium bromide 3% gelatin aqueous solution containing 2 mol% potassium iodide and a 2N silver nitrate aqueous solution were mixed in a gelatin aqueous solution kept at 60°C. A silver iodobromide emulsion was prepared by addition over a period of 80 minutes using a controlled double jet method under the condition of pAg 7°4.

This emulsion was demineralized and washed with water by the flocculation method, and then an aqueous solution of inert gelatin was added and redissolved at 40°C. It was a cubic monodisperse emulsion with an average particle size of 0.28 μm.

To the redissolved emulsion, 10 mg of thiourea dioxide and 30 mg of chloroauric acid were added as an aqueous solution per 1 kg of silver nitrate.
Fog was applied by heating for 90 minutes under the conditions of H6, 5, 65° C., pAg 6.2.

After this, the pH was adjusted to 5.0 and the pAg to 8.6, and Pinacryptol Yellow was added at 1.5 to 1 kg of silver nitrate.
g was dissolved in a mixture of water and methanol and added. After this, the emulsion was divided, and 2x10-'' moles of comparative compounds and exemplified compounds shown in Table 2 were added per mole of silver nitrate, and a hardening agent and a surfactant were added to paper laminated with polyethylene. The amount of silver nitrate is 2.2 per 1rd.
It was coated to give a weight of g.

After heating the thus prepared sample at 50°C for 3 days, it was exposed through a light wedge for sensitometry with a density difference of 0.15, developed with Geracol (manufactured by Mitsubishi Paper Corporation) for 90 seconds at 20°C, fixed, washed with water, Dry.

The photographic characteristics of the developed samples were calculated by removing the reflected density.

The results are shown in Table-2.

(The following is a blank space) Table 2 (Effects of the invention) As shown in Tables 1 and 2, the photographic properties of the direct positive silver halide photographic light-sensitive material of the present invention are sufficiently low.
It shows min, Dmax, and condition are good and has excellent performance.

*3 Sensitivity: Return density 0. 6 (comparative sample Nα22 is set to 100)
γ: Slope between return density 0.2 and 1.5.

(Margin below)

Claims (1)

[Scope of Claims] Consisting of at least one pre-fogged direct positive silver halide emulsion layer on a support, the emulsion layer or an adjacent hydrophilic colloid layer has the following general formula (I). A silver halide photographic material for direct positive use, characterized in that it contains at least one of the compounds shown below. General formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R_1 and R_2 are hydrogen atoms, alkyl groups,
Represents a hydroxyalkyl group or an alkoxy group. However, R_1 and R_2 are never hydrogen atoms at the same time. )