Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Silver compound sensitizer containing
Reexamination Certificate
2002-08-01
2003-10-28
Le, Hoa Van (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Silver compound sensitizer containing
C430S605000
Reexamination Certificate
active
06638705
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a silver halide photographic light-sensitive material having high sensitivity and low fog and after storage, reduced in the fluctuation of photographic performance and the generation of fogging.
Also, the present invention relates to a silver halide emulsion having low fog, high sensitivity, high contrast, excellent reciprocity law property at high illuminance (i.e., at high intensity), small fluctuation of sensitivity due to difference in the exposure condition at exposure, and excellent wet abrasion resistance. More specifically, the present invention relates to a silver halide emulsion for use in a silver halide photographic light-sensitive material, which achieves these properties by a specific gold-chalcogen compound. The present invention also relates to a chemical sensitization method of the silver halide emulsion.
BACKGROUND OF THE INVENTION
In recent years, the color printing paper is demanded to have high performances such as high sensitivity, high image quality and toughness at the processing. To satisfy these requirements, demands for an emulsion having low fog, high sensitivity and high contrast, an emulsion reduced in the fluctuation of sensitivity during storage, an emulsion reduced in the fluctuation of photographic property due to difference in the temperature and humidity conditions at exposure, or an emulsion having excellent wet abrasion resistance are increasing. On the other hand, due to popularization of laser scanning exposure apparatuses, suitability for short-time and high-intensity exposure becomes one of important performances. A great characteristic feature of laser scanning exposure is to enable high-speed exposure and elevation of resolution. If this exposure system is applied to color printing paper, the color printing paper is required to have suitability for unusually very short-time (specifically 10
−6
second) and high-intensity exposure.
A gold sensitization method is effective means for achieving high sensitivity. It is long known to use an Au(III) compound such as chloroauric acid. The chloroauric acid is satisfactorily stable in an aqueous solution but has a problem in the photographic properties such as sensitivity, gradation, suitability for high-intensity exposure, fluctuation of sensitivity during storage, wet abrasion resistance and toughness against the temperature and humidity environment at exposure. Thus, improvements in these points are being demanded.
A gold(I) compound containing a mesoionic ligand (hereinafter referred to as a “mesoionic gold(I) compound”) is known as the gold compound for use in the gold sensitization and JP-A-4-267249 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”) discloses that this compound is useful for the production of a high-sensitivity and high-contrast emulsion. However, as disclosed in JP-A-11-218870, the mesoionic gold(I) compound has a problem in the stability in a solution. The stability in a solution is an indispensable condition for the stable production of emulsions having a constant quality and therefore, an improvement is demanded.
For solving this problem, JP-A-11-218870 proposes a method of using a gold(I) complex of a mercapto compound. This gold sensitizer is improved in the solution stability but still undergoes decomposition to fail in satisfactorily solve the problem. Furthermore, this compound gives insufficient photographic properties, for example, in wet abrasion resistance and toughness against temperature and humidity environment at exposure. Thus, an improvement is demanded.
As understood from the use of Au
2
S in U.S. Pat. No. 2,642,361, the chemical sensitization using gold sulfide colloid is one long known useful sensitization method. The production process of gold sulfide colloid is described, for example, in
Research Disclosure
, 37154 (1995) in addition to the above-described U.S. patent. As described in JP-A-11-218870, the sensitization by this gold sulfide colloid has a problem of giving many distributions and undesired sensitometry properties. Also, the preparation of gold sulfide colloid has a problem of requiring very long time and large expense.
Furthermore, in recent years, the silver halide photographic material is demanded to have high sensitivity and the importance of a high aspect ratio emulsion is increasing. For elevating the sensitivity of a silver halide photographic emulsion, chemical sensitization using various chemical substances so as to obtain desired sensitivity, gradation or the like is usually employed. Various chemical sensitization methods are known and representative examples thereof include sulfur sensitization, selenium sensitization, tellurium sensitization, noble metal sensitization using, for example, gold, reduction sensitization and a combination thereof. As described, for example, in JP-A-6-332093, it is known to elevate the sensitivity by combining selenium sensitization with a high aspect ratio tabular grain emulsion. Recently, the demand for high sensitivity, excellent graininess and high sharpness in a silver halide photographic light-sensitive material and for rapid processing by expediting the progress of development is strong and various improvements have been made on the above-described sensitization methods.
Among those sensitization methods, the tellurium sensitization method and tellurium sensitizer in general are disclosed in U.S. Pat. Nos, 1,623,499, 3,320,069, 3,772,031, 3,531,289 and 3,655,394, British Patents 235,211, 1,121,496, 1,295,462 and 1,396,696, Canadian Patent 800,958, JP-A-61-67845, JP-A-61-20940, and U.S. Pat. Nos. 1,574,944 and 4,704,349, but the detail and specific description of tellurium sensitizer is known only in British Patents 1,295,462 and 1,396,696 and Canadian Patent 800,958.
Specifically, colloidal tellurium and potassium telluride described, for example, in Canadian Patent 800,958, which are conventionally known tellurium sensitizers, have an excellent aspect such that higher sensitivity can be achieved as compared with sulfur sensitization usually performed widely in the art. However, the colloidal tellurium is prepared by using a strong reducing agent such as stannous chloride and therefore, cannot have good reproducibility due to remaining of the reducing agent or subtle changes in the preparation conditions. Also, the potassium telluride has a problem in that the compound itself is low in stability, difficult to deal with and poor in the reproducibility.
The tellurium compounds are described also in JP-A-53-57817, JP-A-2-118566, JP-A-2-140736, U.S. Pat. Nos 4,607,000 and 4,607,001, JP-A-62-234153, JP-A-2-158730 and JP-A-3-91735, however, these are very inferior in the chemical sensitization (tellurium sensitization) intended in the present invention.
As the emulsion has higher sensitivity, the fog generated during storage is liable to more increase and when the higher sensitivity is achieved by higher aspect ratio or by selenium sensitization or tellurium sensitization, there arises a problem that the photographic property greatly changes in aging, such as generation of fog during storage. Accordingly, in the art of proceeding toward higher sensitivity, a technique for improving storability is strongly demanded at the same time with higher sensitivity by higher aspect ratio or by selenium sensitization or tellurium sensitization. Of course, such a technique should not involve any problem such as reduction in sensitivity.
On the other hand, gold sensitization is a long known important technique for obtaining a high-sensitivity emulsion and, for example, East German Patent 249,106 discloses a gold sensitization method using a gold complex of a thioether compound or a gold complex of a mercaptoamino acid, JP-A-4-67032 discloses a gold sensitization method using a gold complex having a heterocyclic ligand, and European Patent 915,371 discloses a gold sensitization method using a gold complex of a mercapto compound having a water-soluble group.
JP-A-4-204724 describes a method for applying g
Inaba Tadashi
Mizuno Masafumi
Sasaki Hirotomo
Suzuki Hiroyuki
Yamada Kohzaburoh
Fuji Photo Film Co. , Ltd.
Le Hoa Van
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