JPH0574807B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a silver halide photographic light-sensitive material with improved photographic properties, furthermore, fogging is prevented and
The present invention also relates to a silver halide photographic material that achieves high sensitivity and excellent storage stability. [Prior Art] In recent years, demands on silver halide photographic light-sensitive materials (hereinafter simply referred to as light-sensitive materials) have become increasingly strict, and in particular, there is a strong demand for the development of light-sensitive materials with high sensitivity and excellent image characteristics. Conventionally, in order to obtain a silver halide emulsion with high sensitivity, a silver halide emulsion in which the halogen composition is different inside the silver halide grains and in the vicinity of the surface has been actually used. Furthermore, by using a monodispersed emulsion,
Quantum efficiency is improved, making it possible to obtain emulsions with high sensitivity and low fog, and also in the chemical sensitization process.
It is now expected that sensitization can be achieved efficiently while maintaining low fog density. However, in reality, chemical sensitization is difficult to control when a substantially monodisperse emulsion is chemically sensitized, and not only low fog and high sensitivity cannot be achieved as expected, but also undesirable results in storage stability. There is a lot to gain. One of the causes of this is the gold-gelatin complex. In other words, the gold ions of the gold sensitizer, which is commonly used as a chemical sensitizer, form a complex (gold-gelatinate) with gelatin and are captured in the gelatin, making it difficult to control chemical sensitization and preventing capture. The gold ions removed have a negative effect on the storage stability of photosensitive materials. [Object of the Invention] The object of the present invention is to solve the above-mentioned inhibition of chemical sensitization by gold-gelatinate, to achieve stable control of chemical sensitization, and to provide a photosensitive material that has high sensitivity, low fog, and excellent storage stability. It's about doing. [Structure of the Invention] As a result of repeated studies for the above-mentioned purpose, the present inventors have discovered a method for producing a photosensitive material with high sensitivity, low fog, and excellent storage stability much more stably than conventional methods. . That is, the presence of a chalcogen sensitizer, a gold sensitizer, and a water-soluble salt of Pd produces core/shell type silver halide grains that are substantially monodisperse and have different silver iodide contents on the grain surface and inside the grain. By performing chemical ripening below, gold ions were released from the gold-gelatinate and adsorption of gold ions to silver halide grains was promoted, thereby making it possible to stably control chemical sensitization. A light-sensitive material obtained by coating at least one layer of the emulsion thus prepared on a support fully satisfies the above objectives. In the present invention, substantially monodisperse silver halide grains are those in which the shape of each silver halide grain appears uniform when the emulsion is observed using an electron micrograph, the grain size is uniform, and the grain size is the same as that of the following formula. It has a particle size distribution as defined. That is, when the drift deviation S of the particle size distribution is divided by the average particle size, the value is 0.20 or less.

[Formula] S/r≦0.20 The average grain size here refers to the diameter in the case of spherical silver halide grains, or the projected image of the same area in the case of grains with shapes other than cubic or spherical. It is the average value of the diameter when converted into a circular image, and is defined by the following formula, where the individual grain size is ri and the number is ni. =Σni ri/Σni The above particle diameter can be measured by various methods commonly used in the technical field for the above purpose. A typical method is Loveland's "particle size analysis method" AS.
TM Symposium on Light Microscopy, 1955, pp. 94-122 or "Theory of the Photographic Process" by Mies and James, No. 3
Edition, published by Macmillan (1966), Chapter 2. The particle size can be measured using the projected area of the particle or an approximate diameter. If the particles are of substantially uniform shape, the particle size distribution can be described fairly accurately as diameter or projected area. The silver halide emulsion of the present invention is described by P. Glafkides, Chimie et Phyeique Photography.
Photographique) (Paul Montel, 1967);
Photographic Emulsion Chemistry (The
(Focal Press, 1966); Co-authored by VLZelikman et al., Making and Coating Photographic Emulsion (Making and Coating Photographic Emulsion)
Emulsion) (The Focal Press, 1964).
That is, any of the acidic method, neutral method, ammonia method, etc. may be used, and the method for reacting the soluble silver salt with the soluble halogen salt may be an injection mixing method, a simultaneous mixing method, or a combination thereof. It's okay. As one type of simultaneous mixing method, a method in which the pAg in the liquid phase in which silver halide is produced can be kept constant, that is, a so-called controlled double jet method can also be used. The core/shell type silver halide grains in the present invention have a grain structure composed of two or more layers having different silver iodide contents, and the iodine in the vicinity of the surface of the two or more layers is It is preferable that the silver oxide content is lower than that in the interior.
Here, near the surface means that the thickness from the surface is 0.01~
Refers to the 0.3μm part. It is preferable that the difference between the silver iodide content near the surface and inside the surface is 1 mol % or more. In the present invention, the silver iodide content near the surface is preferably as low as possible, and preferably consists essentially of silver bromide. Emulsions containing such silver halide grains have high sensitization efficiency and are particularly suitable for obtaining surface latent image type emulsions. In the core/shell type silver halide grains of the present invention, the gradient due to the difference in content from a layer with a high silver iodide content to a layer with a low silver iodide content may have a sharp boundary; , the boundaries may change continuously and not necessarily be obvious. The distribution state of silver iodide in the above-mentioned silver halide grains can be detected by various physical measurement methods. It can also be investigated by measuring luminescence at such low temperatures. A preferred embodiment of the silver halide grains of the present invention includes 0 to 4 mol% of silver iodide near the surface of the grains, and 2 to 4 mol% of silver iodide inside.
It is silver halide containing 15 mol%. In the present invention, the silver halide composition other than the above-mentioned silver iodide is mainly silver bromide, but it may also contain silver chloride as long as it does not impair the effects of the present invention.
Preferably, the limit is less than approximately 1 mole percent. The silver halide emulsion according to the present invention may be a mixture of octahedral and tetradecahedral grains. The silver halide emulsion having core/shell type silver halide grains of the present invention has substantially monodisperse 1
It can be produced by using a silver halide grain as a core and coating the core with a shell. In order to produce monodisperse silver halide grains of the core, grains of a desired size can be obtained by a double jet method while keeping the pAg constant. For example, a monodisperse silver halide emulsion can be prepared by The method described in JP-A-54-48521 can be applied. For example, potassium iodobromide-
It is produced by adding an aqueous gelatin solution and an ammoniacal silver nitrate aqueous solution to an aqueous gelatin solution containing silver halide seed particles at varying addition rates as a function of time. At this time, highly monodisperse silver halide grains can be obtained by appropriately selecting the time function of addition rate, PH, pAg, temperature, etc. Regarding the method for producing the above-mentioned core/shell type silver halide grains, see, for example, West German Patent No. 169290, British Patent No. 1027146, Japanese Patent Application Laid-Open No. 154232/1983,
You can refer to the descriptions in Japanese Patent Publication No. 51-1417 and other publications. In the present invention, for example, cadmium salts, zinc salts, lead salts, thallium salts, iridium salts or complex salts thereof, rhodium salts or chain salts thereof, etc. may be allowed to coexist in the manufacturing process of silver halide grains according to the present invention. good. The chalcogen sensitizer in the present invention is a general term for sulfur sensitizers, selenium sensitizers, and tellurium sensitizers, and sulfur sensitizers and selenium sensitizers are preferred for use in photography. As the sulfur sensitizer, known ones can be used. For example, thiosulfate,
Examples include allylthiocarbamide, thiourea, allylisothiocyanate, cystine, p-toluenethiosulfonate, and rhodanine. Other U.S. Patents No. 1574944, U.S. Patent No. 2410689, U.S. Pat.
No. 2278947, No. 2728668, No. 3501313, No.
No. 3656955 specifications, West German open application (OLS)
No. 1422869, Japanese Patent Publication No. 1983-24937, Japanese Patent Application Publication No. 1983-
Sulfur sensitizers described in Publication No. 45016 and the like can also be used. The amount of sulfur sensitizer added may be sufficient to effectively increase the sensitivity of the emulsion.
This amount varies over a considerable range under various conditions such as the amount of nitrogen-containing heterocyclic compound added, pH, temperature, and size of silver halide grains, but as a guide, 1 mol of silver halide Approximately 10 ^-7 mol to approx.
About 10 ⁻¹ mol is preferable. A selenium sensitizer can be used instead of a sulfur ring-enhancing agent, and examples of the selenium sensitizer include aliphatic isoselenocyanates such as allyl isoselenocyanate, selenoureas, selenoketones, selenoamides, and selenocarboxylate. acids and esters,
Selenophosphates, diethyl selenide, diethyl diselenide, and other selenides can be used, and specific examples thereof are described in U.S. patents.
It is described in the specifications of No. 1574944, No. 1602592, and No. 1623499. The amount added varies over a wide range as with the sulfur sensitizer, but as a guide, it is preferably about 10 ^-7 mol to 10 ^-1 mol per mol of silver halide. In the present invention, various gold compounds are used as the gold sensitizer, and the oxidation number of gold may be +1 or +3. Typical examples include chlorauric acid salts, potassium chloroaurate, oleic trichloride, potassium oleic thiocyanate, potassium iodooleate, tetracyanoolithic acid, ammonium aurothiocyanate, pyridyltrichlorogold, and the like. The amount of gold sensitizer added varies depending on various conditions, but as a rough guide, it is preferably in the range of about 10 ^-7 mol to 10 ^-1 mol per mol of silver halide. Preferred compounds that release gold ions from gold-gelatinade and promote adsorption of gold ions to silver halide grains have the following general formula []
There is a water-soluble salt of Pd shown by, but of course, it is not limited to this. General formula [] R ₂ PdX ₄ In the formula, R represents a hydrogen atom, ammonium or an alkali metal, and X represents a halogen atom. Specific compounds include Na ₂ PdCl ₄ ,
Examples include (NH ₄ ) ₂ PdCl ₄ , and particularly preferred is ammonium tetrachloropalladate (NH ₄ ) ₂ PdCl ₄ . The amount added is preferably in the range of 10 to 100 times the stoichiometric ratio (molar ratio) to the gold sensitizer. The timing of addition may be at the start of chemical ripening, during ripening, or after the end of ripening, but preferably during chemical ripening, and particularly preferably at the same time as or before or after the addition of the gold sensitizer. In the present invention, reduction sensitization can also be used in combination. The reducing agent is not particularly limited, but includes known stannous chloride, thiourea dioxide, hydrazine derivatives, polyamines, and the like. Although reduction sensitization is carried out during the growth of silver halide grains, it is preferably carried out after completion of chalcogen sensitization, gold sensitization, and sensitization with the water-soluble salt of Pd of the present invention. Furthermore, the silver halide grains used in the present invention can be chemically ripened in the presence of a silver halide solvent, thereby making it possible to achieve significantly higher sensitivity, which is preferable. Examples of silver halide solvents used in the present invention include U.S. Pat.
3574628 specifications, JP-A-54-1019, JP-A No. 54-
(a) Organic thioethers described in Publication No. 158917, etc., JP-A-53-82408, JP-A-55-77737, JP-A-55-
(b) Thiourea derivatives described in No. 2982 publications, etc.
(c) A silver halide solvent having a thiocarbonyl group sandwiched between an oxygen or sulfur atom and a nitrogen atom, described in JP-A No. 144319-1983
(d) Imidazole, (e) described in Publication No. 100717
Examples include sulfites, (f) thiocyanates, and the like. These specific compounds are shown below. (a)

[ka] (b)

[ka] (c)

[ka] (d)

〔Example〕

The present invention will be specifically described below with reference to Examples, but the present invention is not limited thereto. Example 1 A monodisperse core/shell type silver iodobromide emulsion (grain size distribution S/=
0.12, shell thickness 0.3μ, silver iodide content 2 mol % in core part, 0.5 mol % in shell part, tetradecahedral crystal).
This emulsion was divided into six parts, and each emulsion was divided into six parts: sodium thiosulfate, dimethylselenourea, chloroauric acid, ammonium thiocyanate, 4-hydroxy-6-methyl-
1,3,3a,7-tetrazaindene and a sensitizing dye (structure below) were added, one was added as is (referred to as emulsion A), and the other was further added with ammonium tetrachloropalladate() in the amounts shown in Table 1. After changing and adding (referred to as emulsions B, C, D, E, F),
Chemical sensitization and spectral sensitization were performed under optimal conditions. [Sensitizing dye]

[ka]

[Chemical formula] 4-hydroxy-6-methyl-1,3,
3a,7-tetrazaindene, 1-phenyl-5
- Mercaptotetrazole, saponin as a coating aid, appropriate amounts of 1,2-bis(vinylsulfonyl)ethane as a hardening agent, and 3 g of polyvinylpyrrolidone were added, and the following color coupler,
dodecyl gallate, tricresyl phosphate,
Add a dispersion of ethyl acetate, triisopropylnaphthalene sodium sulfonate and gelatin;
Coated on a triacetate base and dried to form a sample (A
~F). [Color coupler]

[Color developer composition]

4-amino-3-methyl-N-ethyl-N-
(β-Hydroxyethyl)aniline sulfate 4.8g Anhydrous sodium sulfite 0.14g Hydroxylamine 1/2 sulfate 1.98g Sulfuric acid 0.74g Anhydrous potassium carbonate 28.85g Anhydrous potassium bicarbonate 3.46g Potassium bromide 1.16g Anhydrous potassium sulfite 5.10g Nitrilotriacetic acid trisodium salt (monohydrate)
1.20g Sodium chloride 0.14g Potassium hydroxide 1.48g Add water to make 1 and adjust the pH to 10.0. [Bleach solution composition] Ethylenediaminetetraacetic acid iron ammonium salt
100.0g Ethylenediamineacetic acid diammonium salt 10.0g Ammonium bromide 150.0g Glacial acetic acid 10.0ml Add water to 1 and adjust the pH to 6.0. [Fixer composition] Ammonium thiosulfate (70% aqueous solution) 175.0g Anhydrous sodium sulfite 3.6g Sodium metasulfite 2.3g Add water to 1 and adjust the pH to 6.0. [Stabilizing liquid composition] Formalin (37% aqueous solution) 5.0ml Konidax (manufactured by Konishiroku Photo Industry Co., Ltd.)
Add 7.5ml water to make 1. The sensitometry results are shown in Table 1 below.
Note that the sensitivity is expressed relative to the sensitivity of emulsion A as 100.

[Table] From the results in Table 1 above, it is clear that low fog and high sensitivity can be achieved by adding 10 to 100 parts of palladium salt to 1 part of gold salt in a stoichiometric ratio. Table 2 shows the results of examining the thermal stability of Samples A and D.

[Table] From the above results, it can be seen that Sample D according to the present invention has improved storage stability at high temperatures, and in particular, an increase in fog is suppressed. Example 2 Using the monodisperse core/shell type silver iodobromide emulsion used in Example 1, chemical sensitization and spectral sensitization were carried out under the same conditions as for Emulsions A and D of Example 1. These emulsions were treated with the same stabilizers and couplers as in Example 1.
A coupler dispersant, a hardening agent, a coating aid, etc. were added, and the mixture was coated onto a support, dried, and subjected to sensitometry. Table 3 shows the results of repeating the above process and comparing the stability of the sensitization process with and without Pd salt. The sensitivity is that of sample A obtained from emulsion A in Example 1.
Expressed relatively as 100.

[Table] From the above results, it can be seen that the addition of the Pd salt according to the present invention greatly stabilized the sensitization process. Example 3 Apart from the monodisperse silver iodobromide tetradecahedral crystal emulsions (A, D) used in Example 1, a polydisperse silver iodobromide twin crystal emulsion (average grain size 1.5μ, S/=0.34iodine) was used. A silver oxide containing 2 mol % (uniformly distributed in the grains) was prepared, and both were subjected to chemical sensitization and spectral sensitization in the same manner as in Example 1. These sensitized emulsions were coated on a support in the same manner as in Example 1, dried (Samples G and H), and subjected to sensitometry. The results are shown in Table 4. The sensitivity is shown as a relative value, with the sensitivity of sample A being 100.

[Table] As is clear from the table, monodisperse emulsions (and have a non-uniform silver halide composition structure) are superior to polydisperse emulsions.
The effect of increasing sensitivity by adding Pd salt is greater. Example 4 A monodisperse core/shell type silver iodobromide emulsion with an average grain size of 0.9μ (S/γ=0.10, shell thickness 0.016μ, silver iodide content 2 mol% in the core part, 0 mol% in the shell part) was prepared. Prepared. This was divided into two parts, each containing sodium thiosulfate, dimethylselenourea, chloroauric acid, ammonium thiocyanate, 4-hydroxy-6-methyl-
1,3,3a,7-tetrazaindene was added, one was left as is (emulsion), the other was further added with ammonium tetrachloropalladate (emulsion J), and then chemically ripened under optimal conditions. did. After completing the training, the stabilizer used in Example 1, a commonly used hardening agent, and a coating aid were added, and the mixture was coated on a polyethylene terephthalate base and dried. Sensitometry of these samples was performed as follows. For exposure, a tungsten bulb (color temperature 5400〓) was used as the light source, and a 1/50 light was used through an optical wedge.
I took a second exposure. Develop with the following developer at 20℃, 10
I did it for a minute. Metol 2.5g Ascorbic acid 10.0g Sodium metaborate dihydrate 44g Potassium bromide 1.0g Add water 1 The results are shown in Table 5. Sensitivity is the sensitivity of the sample.
Relative sensitivity was expressed as 100.

[Table] As is clear from the table, it can be seen that sample J of the present invention has significantly improved storage stability not only at room temperature but also at high temperature.

Claims (1)

[Scope of Claims] 1. In a silver halide photographic material having at least one silver halide emulsion layer on a support, at least one of the silver halide emulsion layers has a silver iodide content near the surface. A silver halide obtained by chemically ripening substantially monodisperse core/shell type silver halide grains that differ internally from each other in the presence of a chalcogen sensitizer, a gold sensitizer, and a water-soluble salt of Pd. A silver halide photographic material characterized by containing an emulsion. 2. The silver halide photographic material according to claim 1, wherein the silver halide grains are chemically ripened in the presence of a silver halide solvent. 3. The silver halide photographic material according to claim 1 or 2, wherein the silver halide grains are silver iodobromide grains. 4. The silver halide photographic material according to claim 1, 2, or 3, wherein the water-soluble salt of Pd is a compound represented by the following general formula []. General formula [] R ₂ PdX ₄ [wherein R represents a hydrogen atom, ammonium or an alkali metal, and X represents a halogen atom]. ] 5. The amount of the compound represented by the general formula in the preceding paragraph is 10:1 to 10:1 to the gold sensitizer in terms of stoichiometric ratio (molar ratio).
The silver halide photographic light-sensitive material according to claim 1, 2, 3, or 4, characterized in that the ratio is in the range of 100:1.