JPS6343736B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a silver halide photographic emulsion, and more particularly to an ultra-low sensitivity silver halide photographic emulsion for light-sensitive materials for bright rooms. In recent years, in the printing field, the complexity of printed matter,
With the development of scanners, there is a need to improve the efficiency of the turning process. In response to this demand, improvements have been made in terms of equipment such as printers and in light-sensitive materials. Silver halide photosensitive materials with a sensitivity of 10 ^-4 to 10 ^-5 have been developed. However, these light-sensitive materials have drawbacks such as soft tone, low sensitivity to printer light sources, and lack of suitability for processing with Lithium developer, and further improvements are desired. As a method of reducing the photosensitivity of photosensitive materials, inorganic desensitizers such as cupric chloride, rhodium chloride, and iridium chloride, and organic desensitizers such as pinacryptor yellow and phenosafranine are used in silver halide emulsions. The method is generally known. However, by these conventionally known means, it is not possible to obtain a photosensitive material for bright room use that fully satisfies market requirements. The first object of the present invention is to provide a silver halide photographic emulsion with ultra-low sensitivity. A second object of the present invention is to provide a silver halide photographic emulsion that exhibits high sensitivity and high contrast when printed with a light source rich in ultraviolet light. A third object of the present invention is to provide a silver halide photographic emulsion that can be handled in a bright room where ultraviolet light is excluded. A fourth object of the present invention is to provide a silver halide photographic emulsion that exhibits sufficient characteristics even in a Lith type developer. A fifth object of the present invention is to provide a method for producing a silver halide emulsion as described above. Other objects of the invention will be understood from the description herein. The purpose of the present invention is to prepare a silver halide emulsion containing 90 mol% or more of silver chloride by adding a water-soluble rhodium salt to the silver halide emulsion in the presence of 10 ^-3 to ^{10 -5} mol/mol Agx. This is achieved by incorporating a compound represented by the general formula []. General formula [] In the formula, R ₁ , F ₂ and R ₃ each represent a hydrogen atom, an amino group, a hydroxyl group, a mercapto group, an alkyl group or an aryl group. The following are representative compounds represented by the general formula [] that are advantageously used in the present invention. Such compounds can be added to the photographic emulsion at any time. The amount added varies depending on the time of addition, but is generally 0.5 to 100 mg/mol.
Agx, preferably 1 to 50 mg/mol Agx. Naturally, if the amount added is small, the effect will not be apparent.
On the other hand, if the amount is too large, particle formation will be inhibited and development will be significantly inhibited, making it impossible to achieve the object of the present invention. As the silver halide used in the silver halide emulsion of the present invention, silver chloride, silver chlorobromide, silver chloroiodobromide, and silver chloroiodide are used, but in any case, the content of silver chloride is 90 mol% or more. , preferably 95 mol% or more. If the hydrochloric acid content is less than 90 mol %, the sensitivity will be high, the tone will be soft, and the density will decrease, making it impossible to achieve the object of the present invention. Examples of water-soluble rhodium salts used in the present invention include rhodium dichloride, rhodium trichloride, and ammonium hexachlororhodate, but preferably a complex compound of rhodium trichloride and a halogen. The amount added is 10 ^-3 per mole of silver halide.
10 ^-5 mol, more preferably 10 ^-3 to 10 ^-4 mol. If the amount of the water-soluble rhodium salt is 10 ^-3 or more, although there is still a tendency for desensitization, the object of the present invention cannot be achieved because the tone becomes soft. On the other hand, if it is less than 10 ^-5 mol, the sensitivity required for use in a bright room, which is the objective of the present invention, cannot be lowered, and the objective cannot be achieved. In the present invention, the water-soluble rhodium compound is present during the preparation of the silver halide emulsion.
The time of preparation refers to the process of emulsification and physical ripening, and it may be added by any method at any time during this process. However, the preferred addition time is during emulsification, and a particularly preferred method is to add a water-soluble rhodium salt to the halide solution.
This is because in order to maximize the high contrast desensitization effect of rhodium, rhodium atoms must be uniformly distributed inside and on the surface of silver halide grains, and for this purpose it is necessary to add them to the halide liquid. On the other hand, rhodium atoms added during physical ripening are thought to be distributed only on the particle surface, making it difficult to achieve the goal of low sensitivity. Furthermore, as a method for preparing an emulsion, forward mixing, back mixing, semi-back mixing, and simultaneous mixing are all possible.
The most preferred method is the simultaneous mixing method. The reason is the same as above. In addition, there are ammonia method, neutral method, and acid method for preparing emulsions, but when the silver chloride content is 90 moles or more as in the present invention, the ammonia method may cause fog or increase sensitivity. , is not suitable for the purpose of the present invention. The distribution of silver halide grains in the emulsion may be either monodisperse or heterodisperse, but monodisperse is preferable for uniform grain sensitivity. Further, the grain crystal habit may be cubic, octahedral, or any other shape. The particle size is preferably 1μ or less, preferably 0.5μ or less. More preferably, it is 0.3μ or less. This is because it is necessary to make the developed silver particles finer in order to prevent them from becoming rough and to achieve the required photographic density with a small amount of silver in order to save resources. The emulsion thus prepared can also be chemically sensitized (for example, sulfur sensitization, reduction sensitization, etc.) using a chemical sensitizer. However, the object of the present invention can be achieved without any chemical sensitization. Furthermore, the emulsion thus prepared may contain stabilizers such as tetrazaindenes, antifoggants,
For example, triazoles, tetrazoles, covering power improvers, anti-irradiation agents, such as oxanol dyes, dialkylaminobenzylidene dyes, etc., wetting agents, such as terraces, and other additives used in general photographic emulsions, such as spreading agents, hardeners. It is possible to add agents, etc. The silver halide emulsion of the present invention is coated on a support, and commonly used supports such as polyester base, baryta paper, laminated paper, glass, etc. are used. As a light source for exposing the silver halide photographic light-sensitive material thus prepared, a light source rich in ultraviolet light used mainly in the printing field, such as a xenon, metal halide, mercury lamp, or ultra-high pressure mercury lamp, is used. As the developer for the silver halide emulsion of the present invention,
Any developer used for general silver halide photographic light-sensitive materials or a lithium developer can be used. As developing agents, hydroquinone, chlorhydroquinone, dihydroquinobenzenes such as catechol, 1-phenyl-3-pyrazolidone, 1-phenyl-4,4-dimethyl-3-pyrazolidone, 1-phenyl-4-methyl-4- 3-pyrazolidones such as hydroxymethyl-3-pyrazolidone, 1-phenyl-4-methyl-4-hydroxymethyl-3-pyrazolidone, N-methyl-p-aminophenol, N-(4-hydroxyphenyl)glycine p-phenylene diamines such as para-aminophenols such as β-methanesulfonamidoethyl, ethylaminotoluidine, N,N-diethyl-p-phenylene diamine, and ascorbic acids. An aqueous solution containing one or more of the active ingredients is used, along with potassium sulfite, sodium formaldehyde bisulfite, hydroxylamine, preservatives such as ethylene urea, development inhibitors such as potassium bromide and potassium iodide, and 1-phenyl -5-
Mercaptotetrazole, 5-nitrobenzimidazole, 5-nitrobenztriazole, 5-
Organic antifoggants such as nitroindazole, 5-methyl-benztriazole, 4-thiazoline-2-thione, alkaline and buffering agents such as sodium carbonate, potassium hydroxide, borax, diethanolamine, triethanolamine,
Salts such as sodium sulfate, sodium acetate, sodium citrate, water softeners such as EDTA-2Na, nitrotriacetic acid, hydroxyethylenediaminetriacetic acid, developer hardeners such as glutaraldehyde, diethylene glycol, dimethylformamide, ethyl alcohol. , solvents for developing agents and organic inhibitors such as benzyl alcohol, methylimidazoline, methylimidazole, average molecular weight
Development accelerators such as polyethylene glycol 1540 and dodecylpyridinium bromide can be added. Although the pH of the developer is not subject to any restrictions, a pH of 8 to 13 is usually used, preferably 9 to 12. When developing a light-sensitive material obtained using the silver halide emulsion of the present invention, development sludge may be produced. This sludge contaminates the developer, adheres to and contaminates the photosensitive material, contaminates the wall surface during automatic processor processing, and obstructs the circulation of the developer, making it impossible to obtain desirable photographic performance. . It has been found that such a phenomenon can be suitably prevented by adding 1-phenyl-5-mercaptotetrazole and its derivatives to the developer. Generally, the amount of this compound added to a developer is 1 to 20 mg per developer, but there is no practical sludge-preventing effect within this amount range. In order to properly prevent sludge, the amount is 40 to 300 mg per developer, preferably 60 to 300 mg.
The objective is achieved by adding 200 mg. Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto. Example 1 A silver chlorobromide emulsion having the silver bromide content and the added amounts of rhodium chloride and compound-1 shown in Table 1 was prepared at 60%
It was prepared by simultaneous mixing method at ℃ for 15 minutes. Rhodium chloride was dissolved in a common salt solution and added to the halide solution.

[Table] The emulsion thus prepared was desalted and redispersed to obtain a monodispersed emulsion with a grain size of 0.2μ. A small amount of sodium thiosulfate was further added to these emulsions and chemically sensitized at 50°C for 30 minutes, and 6-methyl-4-hydroxy-1,3,3a,7 was added as a stabilizer.
-tetrazaindene, 1-phenyl-5-mercaptotetrazole as an antifoggant, 4,5-dimethyl-4-thiazoline-2-thione as a sensitizer, tartrazine as an irradiation inhibitor, saponin as a spreading agent, hardening agent Mucochloric acid was added thereto, and the film was coated on a film base to a silver content of 3.5 g/m ² and dried. The sample thus obtained was exposed to light through a light wedge using a bright room printer (HMW-215 manufactured by Oak Seisakusho) and processed with the following developer. Developer formulation Hydroquinone 16g Formaldehyde and bisulfite 50g Adduct with sodium Potassium sulfite 4g Potassium carbonate 50g Boric acid 2g KBr 2.5g Triethylene glycol 49g EDTA・2Na 2g Diethanolamine 7g 5-nitroindazole 3mg Ethylene urea 0.5g Polyethylene glycol (average molecular weight 1500)
Add 0.2g sodium hydroxide 1g water to 1000c.c. Development conditions are 27°C, 1 minute 40 seconds and 2 minutes. In addition, a fading light (Toshiba FL40SW/NU) approximately 500
After 30 minutes of irradiation under lux, the same development process as above was performed and fogging was measured. Development conditions: 27℃, 1 minute
It is 40 seconds. The results are shown in Table-2.

[Table] It is represented by symbols.
As shown in Table 2, Sample A- according to the present invention has a high γ and has little variation due to development time, and can be used in a bright room. Example 2 Using the emulsion A- of Example 1, samples to which the compound of the present invention was added as shown in Table 3 were prepared. Then, the same treatment as in Example 1 was performed. The results are shown in Table-3.

[Table] From the results in Table 3, it can be seen that the samples according to the present invention have high γ, have little sensitivity fluctuation due to development time, and have little fogging.

Claims (1)

[Scope of Claims] 1. A silver halide photographic emulsion containing at least 90 mol % of silver chloride, prepared in the presence of 10 ^-3 to 10 ^-5 mol of a water-soluble rhodium salt per mol of silver halide, A silver halide photographic emulsion characterized by containing a compound represented by the following general formula []. General formula [] [In the formula, R ₁ , R ₂ and R ₃ each represent a hydrogen atom, an amino group, a hydroxyl group, a mercapto group, an alkyl group or an aryl group. ]