Granulated solid processing agent for silver halide...

Radiation imagery chemistry: process – composition – or product th – Nonradiation sensitive image processing compositions or... – Developer

Reexamination Certificate

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C430S458000

Reexamination Certificate

active

06524780

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a photographic development processing agent (hereinafter referred to as merely “a processing agent”) for a silver halide photographic material (hereinafter sometimes referred to as merely “photographic material”), and specifically relates to a granulated solid processing agent and a producing method of the same.
BACKGROUND OF THE INVENTION
For expediting DP for general customers or for rationalizing collection and delivery work between photo processing shops and processing laboratories, a small scale automatic processor called a mini-lab which is installed at photo processing shops for performing photographic processing has increasingly prevailed in these years. Concentrated liquid processing agents were supplied to mini-labs but there were a variety of problems because the processing agents were liquids, such as the regulations on transportation, the risks of the breakage of containers due to a shock, the inconveniences in handling at processing shops, and the restrictions on storing spaces. For solving these problems, processing techniques of directly adding processing agents to processing tanks are proposed, e.g., a granulated processing agent is disclosed in U.S. Pat. No. 4,923, 786, a tablet type processing agent in JP-A-5-127322 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”), and a solid processing agent in U.S. Pat. No. 5,334,492.
Although a processing agent can be supplied as a solid in accordance with these methods, new problems have been arisen such that a processing agent absorbs moisture when stored for a long period of time and the stability of the agent is impaired, further, the processing agent adheres to each other and solidifies. In particular, when a processing agent contains highly hygroscopic alkali metal hydroxide and thiosulfate, if the above methods of directly adding a solid processing agent to a processing tank is used, since a solid processing agent is placed in a highly humidity condition in a processor until it is added to a processing tank, solidification occurs and hinders development processing operations, which at the same time adversely affect the finished quality of photographs.
For preventing a solid processing from solidifying with the lapse of time, a method of uniformly mixing a composition containing alkyl-substituted hydroxylamine and alkali metal hydroxide is disclosed in JP-A-6-123947, and a granule and a tablet having layer structure of two or more layers are disclosed JP-A-5-93991 and JP-A-5-134362. However, the effect of preventing solidification is not sufficient under a highly humid condition, and none of these methods can solve the above problem.
SUMMARY OF THE INVENTION
Accordingly, a first object of the present invention is to provide a granulated solid processing agent which is excellent in storage stability and compact, and a producing method of the same. A second object is to provide a granulated solid processing agent in which hygroscopicity of the hygroscopic constitutional components, in particular, alkali metal hydroxide and thiosulfate, is reduced, solidification of granules by adhering to each other is prevented, and the storage stability of which in a highly humid environment is conspicuously improved, and a producing method of the same. A third object is to provide a granulated solid processing agent which can be stably used in a processing method of directly adding a granulated solid processing agents to the processing tank of a processor.
These objects of the present invention have been accomplished by the following means:
(1) A granulated solid processing agent for a silver halide photographic material, wherein the granule is a core/shell type spherical granule comprising an internal nucleus and layer structure of one or more layers coating the internal nucleus, and the critical relative humidity of the internal nucleus is 70% or less.
(2) The granulated solid processing agent for a silver halide photographic material as described in the above item (1), wherein the critical relative humidity of the coating layer is higher than the critical relative humidity of the internal nucleus.
(3) The granulated solid processing agent for a silver halide photographic material as described in the above item (1), wherein the internal nuclei of the granules have an average particle diameter of from 0.5 to 5.0 mm.
(4) The granulated solid processing agent for a silver halide photographic material as described in the above item (1), (2) or (3), wherein the granules have an average particle diameter of from 1 to 20 mm.
(5) The granulated solid processing agent for a silver halide photographic material as described in any one of the above items (1) to (4), wherein the granules having a particle diameter of 0.5 mm or less account for 10 mass % or less based on the entire mass of the granulated solid processing agent.
(6) The granulated solid processing agent for a silver halide photographic material as described in any one of the above items (1) to (5), wherein the granule comprises an internal nucleus and layer structure of two or more layers coating the internal nucleus.
(7) The granulated solid processing agent for a silver halide photographic material as described in any one of the above items (1) to (6), wherein the internal nucleus constituting the granule contains alkali metal hydroxide.
(8) The granulated solid processing agent for a silver halide photographic material as described in the above item (7), wherein the alkali metal hydroxide is lithium hydroxide.
(9) The granulated solid processing agent for a silver halide photographic material as described in any one of the above items (1) to (6), wherein the internal nucleus constituting the granule contains thiosulfate.
(10) The granulated solid processing agent for a silver halide photographic material as described in any one of the above items (1) to (9), wherein the surface of the outermost layer of the granule is coated with a water-soluble polymer.
(11) A method for producing a granulated solid processing agent for a silver halide photographic material, wherein the granule is a core/shell type spherical granule comprising an internal nucleus and layer structure of one or more layers coating the internal nucleus, the method comprising the steps of granulating the internal nucleus having critical relative humidity of 70% or less, and then forming a coating layer on the surface of the internal nucleus.
(12) A granulated solid processing agent for a silver halide photographic material, wherein the granule is a core/shell type spherical granule comprising an internal nucleus and multi-layer structure of three or more layers coating said internal nucleus.
(13) The granulated solidprocessing agent for a silver halide photographic material as described in the above item (12), wherein the internal nucleus is composed of four or less compounds.
(14) The granulated solid processing agent for a silver halide photographic material as described in the above item (12) or (13), wherein the internal nucleus contains alkali metal hydroxide.
(15) The granulated solid processing agent for a silver halide photographic material as described in the above item (14), wherein the alkali metal hydroxide is lithium hydroxide.
(16) The granulated solidprocessing agent for a silver halide photographic material as described in the above item (12) or (13) , wherein the internal nucleus contains thiosulfate.
(17) The granulated solid processing agent for a silver halide photographic material as described in any one of the above items (12) to (16), wherein the internal nuclei have an average particle diameter of from 0.5 to 5.0 mm.
(18) The granulated solid processing agent for a silver halide photographic material as described in any one of the above items (12) to (17), wherein the granules have an average particle diameter of from 1 to 20 mm.
(19) The granulated solid processing agent for a silver halide photographic material as claimed in any one of the above items (12) to (18), wherein granules hav

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