Fuji Photo Film Company, Limited

Yasushi Sano

Yoshitsugu Moizumi

Kazuaki Miyashita

In the apparatus for liquid preparation, the silver halide emulsion contained in a dedicated pot is transferred as liquid by a mohno pump via a piping into a measuring tank. The silver halide emulsion transferred into the measuring tank is measured with a load cell and is melted by heating with a jacket while being stirred by a stirrer. Accordingly, even when a small amount is used as in the case of the silver halide emulsion used in the heat-developable photosensitive material, the time for heating the silver halide emulsion, within the time range from the liquid preparation of the silver halide emulsion to its utilization, can be made short to the utmost, and hence the time elapse in melt can be suppressed. Thus, the time elapse in melt, reagent loss, and mutual contamination in the liquid preparation of photographic reagents can be effectively prevented. Under the preparation condition that the silver halide grains are prepared by adding a solution of a water soluble silver salt at an addition rate equal to or larger than 4 kg/min as converted to the weight of silver, the circulating flux of the circulating current at an opening for circulation is set to be equal to or larger than 500 L/min. By setting the circulating flux of the circulating current to be equal to or larger than 500 L/min., the two solutions added from reacting solution feeding pipes can be instantly diluted by a colloidal solution. Thus, the grain diameter and distribution width thereof can be made small in the preparation of silver halide grains for the purpose of producing a silver halide emulsion.

Method and apparatus for liquid preparation of photographic reagent

A coating liquid for photothermographic materials excellent in photographing performance with high sensitivity and reduced fogging and having satisfactory surface conditions is produced. A silver halide particle feeding solution is added and mixed in a mother liquid of coating liquid during a time period between the instant 30 minutes before a substrate is coated with the produced coating liquid by a coating head and the instant just before the coating is started, and in addition, an in-plant mixer is configured such that a mixing container has an inner surface of a spherical shape, an oblate-spherical shape or a prolate-spherical shape so that a mixing blade forms a mixing area in proximity to any part of the inner surface of the mixing container when a rotation axis supporting the mixing blade is driven in a reciprocal manner, whereby the mixing performance of the in-plant mixer is significantly improved.

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Fujinomiya, Japan

Yasushi Sano