Radiation imagery chemistry: process – composition – or product th – Post imaging processing – Developing
Reexamination Certificate
1996-03-18
2002-02-26
Le, Hoa Van (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Post imaging processing
Developing
C430S453000, C430S455000, C430S458000
Reexamination Certificate
active
06350562
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method for processing a silver halide photographic light-sensitive material (hereinafter sometimes referred to as a photographic material or a light-sensitive material) and, particularly, to a fixing solution and a fixing processing method.
BACKGROUND OF THE INVENTION
A silver halide black-and-white photographic material is processed, after being subjected to an exposure, by steps of developing, fixing, washing and drying. In general, a hardening fixing solution containing a water-soluble aluminum salt is used for a hardening processing in the fixing step to shorten the drying time and facilitate a passage of the photographic material in an automatic processor.
However, although the hardening fixing solution containing a water-soluble aluminum salt can prevent generation of a hardly soluble aluminum salt by reducing the pH thereof, a problem of sulfurization arises when it is preserved as a concentrated solution because it contains a thiosulfate as a fixing agent. On the other hand, although the stability of the fixing agent is improved and dyes in the photographic material during processing can be easily dissolved and removed by raising the pH of the hardening fixing solution, the generation of the hardly soluble aluminum salt is accelerated by raising the pH. According, it is preferable that a hardening fixing solution of one ingredient type has a pH of from 4.6 to 4.9. However, the generation of the hardly soluble aluminum salt cannot be completely inhibited if the pH is adjusted to such a range, and particularly the concentrated solution cannot be easily prepared. In general, a boron compound is used to solve these problems in a large amount. The boron compound is carried over to a washing step because the fixing solution is carried over thereto along with the photographic material during processing, and as a result, it is released in environment with a waste water. In the meantime, the environmental preservation has become a world-wide problem in recent years, and it has been strongly demanded in photographic processing to reduce the boron compound contained in a waste water.
To cope with this problem, a method processed by a fixing solution which does not substantially contain a boron compound has been proposed. In this method, a fixing solution is divided into two ingredients, one is an acidic solution containing a water-soluble aluminum salt and the other is a solution containing a thiosulfate and having a pH of from 4.6 to 5.0 or more, and the ingredients are mixed when used. However, it is important and necessary to supply these solutions in one ingredient from the point of conveniences of the supply to users and the usage thereof and further from the production costs.
Regarding this point, it has already been known that an organic acid is effective to prevent the generation of a hardly soluble aluminum compound in the solution used. For example, use of an organic acid such as a gluconic acid, a glycolic acid or a maleic acid instead of a boron compound is disclosed in
Research Disclosure
, No. 18728. In addition to this, examples of replacing a part or the whole of a boron compound with an organic acid are disclosed in
Research Disclosure
, No. 16768 and JP-A-63-284546 (the term “JP-A” as used herein means a “published unexamined Japanese patent application”), but they do not disclose the stability of the solutions which are concentrated. However, when these solutions are supplied to users, it is essential for them to be in the form of concentrated solutions from the point of convenience of the transportation and the storage, and from the viewpoint of reducing the waste package materials, and the storage stability of them is an indispensable characteristic. However, the use of an organic acid in concentrated solution components of one ingredient type hardening fixing solution has not yet been known because a sufficient stability cannot be obtained such that depositions of components arise due to high concentrations of salts of concentrated solution components.
The stabilization of an aluminum salt by an organic acid can be explained by the complex formation thereof but, as described above, components of a concentrated solution of high concentration of salts are liable to be deposited, therefore, it is extremely difficult to apply using methods of organic acids in the known form of solutions used to a concentrated solution. Therefore, whether the stability of one ingredient type concentrated hardening fixing solution can be obtained or not by the use of an organic acid cannot be known at all from the use examples in the form of solutions used.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a concentrated hardening fixing solution of one ingredient type (hereinafter sometimes referred to as “one ingredient type concentrated fixing solution”) which does not substantially contain a boron compound that pollutes the environment and which is excellent in aging stability.
Another object of the present invention is to provide a method for processing a photographic material by using the fixing solution.
These and other objects of the present invention have been achieved by a concentrated fixing solution of one ingredient type which comprises at least a thiosulfate, a water-soluble aluminum salt, and a compound having an absorbance of from 0.25 to 1.15, and does not substantially contain a boron compound, wherein the absorbance is measured by an absorptiometer of ultraviolet light/visible light in a solution having a pH of 4.85 and containing a buffer solution of 1.55 mol/liter of an acetic acid/sodium acetate, 2.5×10
−4
mol/liter of Al
3
+, 2.5×10
−5
mol/liter of the following compound A, and 5×10
−3
mol/liter of a compound for evaluation:
Further, these and other objects of the present invention have been achieved by a method of processing a silver halide photographic material, which comprises the steps of developing an exposed silver halide photographic material, and then processing the developed photographic material with a fixing solution obtained by diluting the above-described concentrated fixing solution to a prescribed concentration.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is described in detail below.
In the present invention, the phrase “which does not substantially contain a boron compound” means that the concentration of the boron compound is 0.04 mol/liter in the fixing solution.
A colorimetric method used in the present invention is a method indirectly representing the stability of a complex formed by an organic acid to be evaluated and Al
3+
by measuring the absorbance of the complex formed by Al
3+
which is not masked by the organic acid and compound A. That is, the smaller the absorbance, the larger is the masking ability of Al
3+
.
Practically, a solution having a pH of 4.85 and containing a buffer solution of acetic acid/sodium acetate (1.55 mol/liter in terms of acetic acid), Al
3+
(2.5×10
−4
mol/liter), compound A (2.5×10
−5
mol/liter), and a compound to be evaluated (5×10
−3
mol/liter) is prepared, and the absorbance of the solution is measured by an absorptiometer of ultraviolet light/visible light at a wavelength of from 500 to 600 nm. The absorbance value of boric acid conventionally used is 1.14 when measured by this method, on the other hand, those of 5-sulfosalicylic acid, iminodiacetic acid, sodium gluconate, malic acid, and tartaric acid are 0.54, 0.90, 0.93, 0.28 and 0.34, respectively.
When a compound having an absorbance value of less than 0.25 by this method is used alone, a sufficient hardening effect cannot be obtained in processing of a photographic material because its masking ability of Al
3+
is too strong. On the other hand, when a compound having an absorbance value exceeding 1.15 is used alone, since its masking ability of Al
3+
is too weak, an aluminum compound is deposited during the preparation of a concentra
Hirano Mitsunori
Okada Hisashi
Watanabe Harumi
Yamada Minoru
Fuji Photo Film Co. , Ltd.
Le Hoa Van
Sughrue & Mion, PLLC
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