Fuji Photo Film Company, Limited

Akira Katoh

Shigeharu Urabe

Yasunori Ichikawa

Hiroshi Ohnishi

Akira Kojima

A process and apparatus for producing silver halide grains wherein by removing water, etc., from a liquid containing fine, silver halide grains formed in a mixer and being added to a reaction vessel, the yield of the silver halide grains grown in the reaction vessel per unit amount of the raw materials used is increased. Also, by removing a portion of the water, used for the dilution, from the liquid being added to the reaction before the addition thereof, the amount of diluting water effective for the formation of silver halide fine grains in the mixer is increased, to thereby form finer silver halide grains in the mixer.

Process of producing silver halide grains and apparatus therefor

An apparatus for forming silver halide grains comprises a reaction vessel for causing the nucleus formation and the crystal growth of silver halide grains. The apparatus further includes: a mixer disposed outside of the reaction vessel and having a high-speed stirring blade; conduits for supplying an aqueous solution of a water-soluble silver salt, an aqueous solution of water-soluble halide, and an aqueous protective colloid solution to the mixer while controlling the rotational speed of the high-speed stirring blade to form fine, silver halide grains; and a conduit for connecting the mixer to the reaction vessel for immediately supplying the fine grains in the mixer to the reaction vessel.

Apparatus for forming silver halide grains

A process of producing silver halide grains by disposing a mixer outside of a reaction vessel for causing a nucleus formation and/or a crystal growth of silver halide grains and containing an aqueous protective colloid solution. The process further includes the steps of: supplying an aqueous solution of a water-soluble silver salt, an aqueous solution of a water-soluble halide(s), and an aqueous solution of a protective colloid to the mixer while controlling the flow rates of the solutions; mixing them while controlling the rotational speed of a stirring blade of the mixer to form fine, silver halide grains; and immediately supplying the fine grains into the reaction vessel to perform the nucleus formation and/or the crystal growth of the silver halide grains in the reaction vessel. The silver halide fine grains thus formed in the mixer are quickly diluted with a liquid withdrawn from the reaction vessel and then the diluted mixture is supplied to the reaction vessel.

Process of forming silver halide grains

A process of forming silver halide grains which comprises disposing a mixer outside of a reaction vessel for causing the nucleus formation and crystal growth of silver halide grains. The process further includes the steps of: supplying an aqueous solution of a water-soluble silver salt, an aqueous solution of a water-soluble halide, and an aqueous protective colloid solution into the mixer to form fine, silver halide grains therein; immediately supplying the fine grains into the reaction vessel; and performing the nucleus formation and crystal growth of the silver halide grains in the reaction vessel. The formation of the fine grains is controlled by controlling the flow rates of the solutions being supplied to the mixer and the r.p.m. of a stirrer provided in the mixer.

A control process and apparatus for the formation of silver halide grains comprising a mixer disposed outside of a reaction vessel containing an aqueous protective colloid solution and causing a nucleus formation (nucleation) and/or a crystal growth of silver halide grains. The process and apparatus further include: supplying an aqueous solution of a water-soluble silver salt, an aqueous solution of water-soluble halide(s), and an aqueous solution of a protective colloid to the mixer through supply conduits while controlling the flow rates of the solutions; mixing them while controlling the rotational speed of a stirrer of the mixer to form fine, silver halide grains; and immediately supplying the fine grains into the reaction vessel through a conduit connecting the mixer to the reaction vessel to perform the nucleus formation and/or the crystal growth of the silver halide grains in the reaction vessel. The control process and apparatus further comprise measuring the silver ion potential of the fine grains formed in the mixer or the silver ion potential in the reaction vessel with an electrode, and controlling the flow rate of at least one of the aqueous silver salt solution, the aqueous halide solution, and the aqueous protective colloid solution being added to the mixer, such that the measured value equals a predetermined value.

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Kanagawa, Japan

Akira Katoh