Fuji Photo Film Company, Limited

Kazuaki Miyashita

Yoshitsugu Moizumi

Yasushi Sano

Junichi Yamanouchi

Yoshihisa Hashi

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 silver halide photographic material has at least one photosensitive silver halide emulsion layer and at least one non-photosensitive hydrophilic colloid layer on a support. The silver coverage per surface is 1.0-2.2 g/m.sup.2. The silver halide emulsion layer contains silver halide grains wherein tabular silver halide grains having an aspect ratio of at least 5 account for at least 50% of the entire projected area of silver halide grains. The silver halide grains have been grown on pure silver bromide or silver chlorobromide grains as nuclei so as to form silver iodobromide or silver chloroiodobromide having a silver iodide content of 0.1-3.20 mol % at the end of growth. This X-ray photosensitive material having high sensitivity and sharpness is used with a regular screen.

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Fujinomiya, Japan

Kazuaki Miyashita