JPH0314164B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a silver halide photographic material in which the surface sensitivity of silver halide grains is improved.More specifically, the present invention relates to a silver halide photographic material in which the surface sensitivity of silver halide grains is improved. The present invention relates to a silver halide photographic material having a sensitized emulsion. In recent years, silver halide photographic light-sensitive materials have been made into fine grains to ensure stability in development processing, that is, running stability in development processing, or stable processing characteristics even in development processing conditions that differ slightly from one photofinishing laboratory to another. There has been a demand for something with high sensitivity and good graininess. For example, Japanese Patent Publication No. 50-36978 shows a photographic emulsion made by the conversion method, and JP-A No. 52-18309 shows a photographic emulsion made by the partial conversion method.
No. 49-106321 discloses a photographic emulsion made by periodically changing pAg. However, these emulsions with a certain degree of graininess have relatively high grain internal sensitivity, and as shown in "The Theory of Photographic Processes" by Mies and James, 3rd edition, page 161, It is difficult to obtain high surface sensitivity with ordinary chemical sensitization, such as sulfur sensitization, reduction sensitization, and heavy metal sensitization. Further, if an attempt is made to obtain an excessively high surface sensitivity, there are problems in that fogging occurs and soft gradations are obtained. Furthermore, conventionally, silver halide photographic materials using silver halide grains having a laminated structure were developed in Japanese Patent Application Laid-open No.
As described in No. 8524, its use as a direct positive silver halide emulsion as an internal latent image type emulsion is indicated due to its high sensitivity inside the grains.
These emulsion grains have excellent graininess, but when attempting to impart surface sensitivity, the above-mentioned problems occur. Furthermore, in recent years, in the photographic industry, there has been a desire for faster development processing, and there has been a demand for silver halide photographic light-sensitive materials having emulsions that are quick to develop and generate less fog even during high-temperature processing. An object of the present invention is to provide a silver halide photographic material containing silver halide grains with small grain size and excellent granularity, which has an emulsion with high sensitivity, high contrast, and little fog. It's about doing. A second object of the present invention is to provide a silver halide photographic material having an emulsion with good manufacturing stability. That is, if the photosensitive material has small variations in photographic properties between product lots, the user will not have to change the usage conditions for each product lot, and can use the product efficiently. Another object of the invention is to provide a silver halide photographic material that is less prone to partial desensitization (hereinafter referred to as pressure desensitization) that occurs when pressure is applied from the front or back side of the silver halide photographic material. It is in. Yet another object of the present invention is to provide a silver halide photographic material that causes less fog even during rapid development processing. It has been found that these above objects can be achieved in the following manner. In other words, silver halide grains absorb silver bromide.
Is it a three-layer structure in which a second layer containing silver chloride of 60 mol% or more is laminated on a core containing 50 mol% or more, and a layer containing 80 mol% or more of silver bromide is provided as the outermost layer, or Or 60mol% silver chloride
It has a two-layer structure in which a core containing the above and an outermost layer containing 80 mol% or more of silver bromide is provided, and the silver halide grain is 0 to 5 mol% of the silver halide grain.
of silver iodide, and the surface of the silver halide grains contains 10 mol% or less of fine-grain silver chloride and 0.01 mol% or less of unstable silver iodide, based on 1 mol of silver halide in the silver halide grains. It has been found that this can be achieved by a silver halide photographic light-sensitive material characterized by having on a support at least one emulsion layer containing silver halide grains chemically sensitized in the presence of sulfur. The other layer of the present invention is preferably made of silver chloride or silver bromide or a mixture thereof, and is preferably silver chlorobromide containing substantially no silver iodide. It may contain less than mol% of silver iodide. The thickness of the nucleus constituting the silver halide grain of the present invention and the laminated layers can be freely selected, but the size of the nucleus is particularly preferably 10 to 50% of the grain size of the silver halide grain. The thickness of the outermost layer is preferably 20% or more of the silver halide grain size. The method for forming the silver halide grains of the present invention is mainly the PAg control-double jet method, but of course the usual double jet method, forward mixing, back mixing, conversion method, acidic method, neutral method, etc.
Although any method such as the ammonia method may be used, the double jet method is particularly preferred in order to improve the graininess. Further, if necessary, a silver halide solvent such as a thioether or a crystal habit control agent such as a mercapto group-containing compound or a sensitizing dye may be used. When forming the silver halide grains of the present invention, platinum group elements such as iridium and rhodium may be included if necessary. The silver halide grains of the present invention may have any shape and may be a regular hexahedron, a regular octahedron, a regular tetradecahedron, or a mixture thereof. The average grain size of the silver halide grains of the present invention is preferably about 0.2 to 2 μm, particularly preferably 0.3 to 1 μm, depending on the purpose. What is the average particle size?
The measurement method is the average value of the diameter of a circle corresponding to the projected area of individual silver halide grains, for example, "Fundamentals of Photographic Engineering - Silver Salt Photography Edition" (edited by the Photographic Society of Japan, published January 30, 1978). It is described on pages 227-228. In order to increase the surface sensitivity of the internal latent image type silver halide grains with the so-called laminated structure obtained in this way and to obtain high-contrast photographic properties with near fog, it is necessary to add 10 mol% to 1 mol of silver halide in the grains. Chemical ripening is carried out in the coexistence of the following fine-grained silver chloride and unstable sulfur of 0.01 mol% or less. The amount of fine grain silver chloride of the present invention is
It is preferably 0.5 to 5 mol % per 1 mol, and the size of the fine silver chloride particles is preferably 0.01 to 0.2 μ. and,
This fine grain silver chloride may be added at any time from after physical ripening and washing with water until the end of chemical ripening. The fine grain silver chloride may be added in the form of silver chloride, or silver ions may be added after chlorine ions are added, or chlorine ions may be added after silver ions are added. Also, it is possible to add only silver ions using chlorine ions after washing with water, but
It is preferable that the chlorine ion is present in an amount equal to or more than the silver ion. Examples of the sulfur sensitizer containing unstable sulfur of the present invention include thiourea, acrylisocyanate, cystine,
Examples include, but are not limited to, alkali, metal thiocyanates, alkaline earth metal thiocyanates, ammonium thiocyanates, alkali metal thiosulfates, ammonium thiosulfates, and sodium thiosulfate (hypo) is particularly preferred. A particularly preferred amount of unstable sulfur is 0.001 to 0.005 mol% per mole of silver halide. The sulfur sensitizer may be added at any time from the time of physical ripening to the end of chemical ripening. Further, the sulfur sensitizer may be added before, during or after the addition of fine silver chloride particles, but substantial chemical ripening proceeds in the coexistence of fine silver chloride particles and unstable sulfur. Further, if necessary, gold sensitization or reduction sensitization may be combined. Such a method of chemical ripening in the coexistence of fine grain silver chloride is shown in, for example, U.S. Pat. By doing so, major problems such as low surface sensitivity, soft tone, and large pressure desensitization, which are disadvantages of silver halide grains having a laminated structure, can be solved, and the granularity, which is the feature of silver halide grains, can be improved. It is possible to make use of it. These are great effects that cannot be predicted from the above-mentioned patents, and will be explained in more detail. That is, silver halide grains having a layered structure are
The particle has a phase boundary surface inside it, and this surface is likely to become an electron trap. For this reason, problems such as large pressure desensitization and low surface sensitivity of photographic emulsions made of silver halide grains having a laminated structure have been solved by sulfur sensitization of these silver halide grains in the coexistence of fine grain silver chloride. This problem can be solved all at once, and a photographic emulsion with a small average grain size and excellent graininess can be obtained. The silver halide emulsion of the present invention is applied to negative-positive type photographic materials having relatively high contrast. For example, it is mainly used for color printing paper, black and white printing paper, photosensitive material for copying, photosensitive material for printing plate making, etc. The silver halide emulsion layer used in the present invention may contain the following compounds commonly used in silver halide photographic materials. Examples of sensitizing dyes include Japanese Patent Publication No. 43-10773 and U.S. Patent No.
Cyanine dyes such as cyanine dyes, merocyanine dyes, and carbocyanine dyes described in No. 3511664, No. 3694217, etc. can be used alone or in combination of two or more. Furthermore, the sensitizing dye may be added at any time from before to after the chemical ripening of the present invention. As stabilizers and anti-fogging agents, for example, U.S. Pat. No. 2,444,607, U.S. Pat.
German Patent No. 3342596, German Patent No. 1189380, German Patent No.
Specifications of No. 2058626 and No. 211841, Special Publication No. 1977
-4133, 39-2825, JP-A-50-22626,
Methods using stabilizers and fog suppressants described in Publications No. 50-25218 and No. 53-133954 may be applied, and particularly preferred compounds include 5,
6-trimethylene-7-hydroxy-S-triazolo(1,5-s)pyrimidine, 5,6-tetramethylene-7-hydroxy-S-triazolo(1,5-s)pyrimidine, 5-methyl-7-hydroxy -S-triazolo(1,5-s)pyrimidine, 7-hydroxy-S-triazolo(1,5-s)
-s) Pyrimidine, gallic acid ester (e.g., isoamyl gallate, dodecyl gallate, propyl gallate, sodium gallate, etc.), mercaptans (e.g., 1-phenyl-5-mercaptotetrazole, 2-mercaptobenzthiazole, etc.), benzene Triazoles (e.g. 5-bromobenztriazole, 4-methylbenztriazole, etc.), benzimidazoles (e.g. 6-brombenztriazole, etc.),
nitrobenzimidazole, etc.). As binders gelatin, colloidal albumin, agar, gum arabic, alginic acid or hydrolyzed cellulose acetate, acrylamide, imidized polyamide, polyvinyl alcohol, hydrolyzed polyvinyl acetate,
For example, British Patent No. 523611, German Patent No.
No. 2255711, No. 2046682, U.S. Patent No. 3341332
It is possible to use water-soluble polymers etc. described in each specification of the issue. Examples of gelatin derivatives include phenylcarbamyl gelatin, acylated gelatin, and phthalated gelatin as described in U.S. Pat. No. 2,614,928 and U.S. Pat. No. 2,525,753; These hydrophilic colloids include gelatin graft-polymerized with polymerizable monomers having ethylene groups such as styrene acrylate, acrylic ester, methacrylic acid, and methacrylic ester described in the book. They are used in auxiliary layers, with or without silver halide, such as filter layers, protective layers, interlayers, etc. As a hardening agent, for example, organic hardening agents such as vinyl sulfone type, cyanuric chloride type, acryloyl type, ethyleneimine type, etc. or inorganic hardening agents such as chromium alum or potassium alum are used alone or in combination of two or more types. be able to. Examples of surfactants include saponin, dodecylbenzenesulfonic acid sodium salt, sodium sulfosuccinate, and JP-A-49-46733;
-10722 and 50-16525 can be used. When the present invention is applied to color photographic paper, various couplers can be used. For example, an open-chain ketomethylene type coupler can be used as a yellow coupler, and a pyrazolone type or pyrazolotriazole type coupler can be used as a magenta coupler. , pyrazolinobenzimidazole, indazolone, and the like can be used. Further, as the cyan coupler, compounds such as phenols and naphthols can be used. Even if these couplers are 4-equivalent type couplers, 2
It may also be an equivalent type coupler. Furthermore, the photographic emulsion in this case is a colored magenta coupler, a colored cyan coupler, or a DIR coupler.
BAR couplers, Wise couplers, combining couplers, etc. may also be used. Further, as ultraviolet absorbers, for example, benzotriazole compounds, thiazolidone compounds, acrylonitriles compounds, benzophenone compounds, etc. may be used, and if necessary, antistatic agents, fluorescent whitening agents, antioxidants, etc. A stain inhibitor or the like can be used. The silver halide photographic material of the present invention is subjected to conventional black-and-white development or color development. Useful color developing agents for color development include aromatic primary amine compounds such as N,N-diethyl-p-phenylenediamine, N-ethyl-N-
Hydroxyethylparaphenylenediamine, 4-
(N-ethyl-N-hydroxyethyl)amino-
2-Methylaniline, 4-N-ethyl-N-β-
Methanesulfonamidoethyl)amino-2-methylaniline, 4-(N,N-diethyl)amino-
Examples include 2-methylaniline, 4-(N-ethyl-N-methoxyethyl)amino-2-methylaniline, and their sulfates, hydrochlorides, sulfites, p-toluenesulfonates, and the like. After color development, bleach-fixing is performed. Preferred bleaching agents for developed silver include polyvalent metal salts of organic acids, such as ferric salts of organic acids. Specific examples include nitrilotriacetic acid, diethylenetriaminepentaacetic acid, ethylene glycol bis(aminoethyl ether)tetraacetic acid, diaminopropanoltetraacetic acid, N-(2-hydroxyethyl)ethylenediaminetriacetic acid, ethyliminodipropionic acid, and cyclohexanediaminetetraacetic acid. There are iron salts such as acetic acid and ethylenediaminetetraacetic acid. Further, iron salts of polycarboxylic ferrous acids such as oxalic acid, malonic acid, succinic acid, tartaric acid, malic acid, tartaric acid, citric acid, and salicylic acid as shown in JP-A-49-107737 may also be used. As the polyvalent metal, in addition to the above-mentioned ferric salts, cupric salts and cobalt salts may be used. Further, depending on the purpose, inorganic polyvalent metal salts such as ferric chloride and ferric sulfate may be used. In addition, as a fixing agent, conventionally known thiosulfates, thiocyanates, etc., and
water-soluble alkali metal salts such as potassium bromide, ammonium bromide, sodium iodide, etc. or ammonium bromide described in JP-A-48-101934;
Alternatively, it can also contain iodide. Further, in combination with color development and bleach-fixing, various treatments such as prehardening, neutralization, water washing, and stabilization can also be performed. Further, the silver halide photographic emulsion of the present invention is generally coated and dried on a suitable support to produce a silver halide photographic light-sensitive material, and the supports used at this time include paper, glass, cellulose acetate,
A support such as cellulose nitrate, polyester, polyamide, or polystyrene, or a laminate of two or more substrates such as a laminate of paper and polyolefin (polyethylene, polypropylene, etc.) is used. This support is generally subjected to various surface improvement treatments to improve its adhesion to silver halide emulsions.
For example, those that have been subjected to surface treatment such as electron impact treatment or undercoat treatment to provide an undercoat layer are used. The silver halide photographic emulsion is coated and dried on this support by a commonly known coating method, such as dip coating, roller coating, bead coating, curtain flow coating, etc., and then dried. EXAMPLES The present invention will be specifically explained below with reference to Examples, but the present invention is not limited thereto. Example 1 Emulsion preparation method

【table】

[Table] As shown in Table 1, while stirring No. () liquid at 60℃, mix it with No. () and () liquids in a controlled manner so that the PAg is 7.2, and then
Add No. () and () solutions to this mixed solution while controlling the PAg to 8, lower the temperature to 40℃, flocculate with magnesium sulfate, wash with water, and add No. () solution to the mixture. redispersed. The obtained silver halide emulsions (A) and (B) have dodecahedral grains with an average grain size of 0.4 μm, and when taking the grain size distribution of each, the half-width is as follows for emulsion (A).
It was 0.12 μm, and in emulsion (B) it was 0.36 μm, indicating that the graininess was greatly improved. Next, after chemical ripening at 55°C under the following conditions, an antifoggant, 2-hydroxytetrazaindene, and the following edge color dye (a) were added per mole of silver halide.
Sensitized using 2.5 x 10 ^-4 mol of the following magenta coupler (b) dissolved in dibutyl phthalate per ¹ mol of silver halide, hardener bis(vinylsulfonylmethyl) ether, and the above. After the addition, it was coated on RC paper (resin-treated paper) and dried so that the amount of silver coated was 4 mg/dm ² . The sample was KS-7 type sensitometer (Konishi Roku Photo Industry KK)
UV-filter, green filter,
The sample was exposed through an optical wedge for 0.5 seconds, processed with the following color developing solution at 32.8°C for 3 minutes and 30 seconds, and then processed with the following bleach-fix solution for 1 minute and 30 seconds, washed with water and dried to prepare a sample. Color developer composition N-ethyl-N-β-methanesulfone amidoethyl-3methyl-4-aminoaniline sulfate 4.0g Hydroxylamine, sulfate 2.0g Potassium carbonate 25g Sodium chloride 0.1g Sodium bromide 0.2g Anhydrous sodium sulfite 2.0g Benzyl alcohol 10.0ml Polyethylene glycol (average degree of polymerization 400)
Add 3.0ml of water to bring the volume to 1, and adjust the pH to 10.0 using sodium hydroxide. Bleach-fix solution composition Ethylenediaminetetraacetic acid iron sodium salt
60.0g Ammonium thiosulfate 100.0g Sodium bisulfite 20.0g Sodium metabisulfite 5.0g Add water to make 1, and adjust to PH7.0 using sulfuric acid. Redox potential -70mV The density of the magenta dye image formed on each sample is
PDA-60 type densitometer (Konishi Roku Photo Industry)
Table 2 shows the results of measuring the optical density using KK (manufactured by KK).

[Table] Emulsion (A) with a layered structure can achieve high sensitivity and high contrast when chemically ripened in the coexistence of fine grain silver chloride and unstable sulfur (sodium thiosulfate) (Sample No. 3,
4). On the other hand, emulsion (B) which does not have a substantially laminated structure can be sensitized in the coexistence of fine grain silver chloride and unstable sulfur.
The effect is small. Note that here, it represents the slope of the characteristic curve and is an indicator of the gradation level. Example 2 Emulsion preparation method

[Table] At 60℃, while stirring the () solution, add the () and () solutions to the () solution in a controlled manner so that the PAg is 8, then add the () and () solutions.
Add K ₂ (Ircl ₆ ) () in a controlled manner so that it becomes PAg8, then (), ()
After addition, the temperature was lowered to 40°C while controlling the liquid to have a PAg of 9, and the mixture was flocculated using magnesium sulfate, washed with water, and redispersed in gelatin liquid (2008). The average grain size of the obtained emulsions (C) and (D) was 0.8 μm, the crystal habit was close to octahedral, and the grain size distribution was narrow. These emulsions were chemically aged at 55°C under the following conditions and then treated with antifoggant 2.
-Hydroxy-tetrasindene, the following sensitizing dye
The following yellow coupler is obtained by adding (C) to 2.5×10 ^-4 mol dibutyl phthalate per mol of silver halide.
(d) was applied to RC paper at 2×10 ^-1 mol per mol of silver halide and a hardener bis(vinylsulfone methyl ether) was added to give a coated silver amount of 4 mg/dm ² and dried. The sample was exposed to UV light as in Example 1.
A 0.5 second exposure was performed through a blue filter optical wedge. The exposed samples were treated in the same manner as in Example 1 and measured with a densitometer, and the results are shown in Table 4.

[Table] Silver halide emulsion (C) with a layered structure had high sensitivity and high contrast in the presence of fine grain silver chloride and unstable sulfur (sodium thiosulfate), and the pressure desensitization was greatly improved. (Sample No. 13, 14) Example 3 Emulsion preparation method

【table】

【table】

[Table] At 60℃, add the () solution to the () solution over 3 minutes while stirring the () solution, then add the () solution to this over 3 minutes, and after stirring for 10 minutes, the () solution was added over 7 minutes, then solution () was added over 7 minutes, and after stirring for 20 minutes, the temperature was lowered to 40℃, the flocculation was washed with water using magnesium sulfate, and the solution was re-incubated in gelatin solution (). Dispersed. The obtained emulsions (E) and (F) were chemically aged at 55°C under the following conditions in the presence of a sensitizing dye (2.5 x 10 ^-4 mol of the same compound as in Example 2), and then treated with antifoggant 2. −
Hydroxytetrazaindene, yellow coupler (2 x 10 ^-1 mol of the same compound as in Example 2), hardener bis (after adding vinyl sulfone methyl ether, coated silver amount was 4 mg/dm ² on RC paper) The sample was coated and dried. The sample was exposed, processed, and measured with a tensitometer in the same manner as in Example 2, and the results are shown in Table 6.

[Table] Silver halide emulsion (E) with a layered structure has low sensitivity and soft tone (sample Nos. 19 and 20) even when chemically ripened in the presence of unstable sulfur alone, but fine-grain silver chloride and non-silver By chemically ripening in the coexistence of both stable sulfur, we were able to achieve significantly higher sensitivity and higher contrast. (Sample No. 21,
22) On the other hand, silver halide emulsion (F) that does not substantially have a laminated structure does not have this effect.

Claims (1)

[Claims] 1 Silver halide grains have a core containing 50 mol% or more of silver bromide and a second grain containing 60 mol% or more of silver chloride.
It has a three-layer structure with a layer containing 80 mol% or more of silver bromide as the outermost layer, or a core containing 60 mol% or more of silver chloride and 80 mol% of silver bromide. The silver halide grains have a two-layer structure including an outermost layer containing the above, and the silver halide grains contain 0 to 5 mol% of silver iodide, and further the silver halide grains contain 0 to 5 mol% of silver iodide. The surface is silver halide in the silver halide grains.
It is characterized by having at least one emulsion layer on a support containing silver halide grains chemically sensitized in the presence of 10 mol% or less of fine grain silver chloride and 0.01 mol% or less of unstable sulfur based on 1 mol. A silver halide photographic light-sensitive material.