JPH0254932B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an apparatus for producing a silver halide photographic emulsion, and more particularly to a silver halide photographic emulsion manufacturing apparatus that can produce silver halide grains with a narrow grain size distribution and uniform grain crystal habit even in the case of mass production. This relates to manufacturing equipment. U.S. Patent No. 3,145,650, British Patent No. 1,323,464, and U.S. Patent No.
Techniques disclosed in the specification of No. 3692283, Japanese Patent Publication No. 55-10545, etc. are known. These devices were invented to create uniform reaction conditions for water-soluble silver salts and water-soluble halogen salts, and to simplify the manufacturing process of silver halide photographic emulsions. The shape of the halogen salt solution and the supply method of the halogen salt aqueous solution and silver salt aqueous solution have been improved. However, with these techniques, it is difficult to produce silver halide grains with a sufficiently narrow grain size distribution and uniform grain crystal habit due to drawbacks such as lack of uniformity in the circulation flow of the liquid throughout the reaction vessel. On the other hand, Japanese Patent Application Laid-open No. 57-92524 discloses that the circulation flow of liquid throughout the reaction vessel can be made uniform by converting the discharge flow from a stirring blade into a mainly vertical flow using a liquid flow regulating plate. An apparatus for producing a silver halide emulsion is disclosed which improves the performance of silver halide emulsions. However, even with this technology, the circulation of the liquid is still insufficient.
It was not possible to produce silver halide grains with a sufficiently narrow grain size distribution. The present inventors improved the conventional technology and disclosed in Utility Model Application No. 59-3921 a production apparatus for silver halide photographic emulsion that can produce silver halide grains with a narrow grain size distribution and uniform grain crystal habit. did. An apparatus for producing a silver halide photographic emulsion based on this technique is shown in FIGS. 1, 2, and 3. A reaction vessel 1 filled with a protective colloid aqueous solution has a mixer 2 installed so that the interior thereof is filled with the protective colloid aqueous solution, and a halogen salt aqueous solution and silver are introduced into the mixer from its lower open end 21 The aqueous salt solution and the aqueous salt solution are separately supplied through the supply pipes 3 and 3', and both reaction solutions are diluted with the aqueous protective colloid solution in the mixer 2. The liquids are stirred and mixed rapidly to cause a reaction and produce silver halide particles, which are immediately discharged through the conduit 6 into the protective colloid aqueous solution in the reaction vessel above the outside of the mixer 2. The discharge circulating flow discharged from the mixer 2 is made into a uniform vertical flow through the conduit 6, improving the circulation between the reaction vessel and the mixer, and uniformizing the growth process of individual silver halide grains. This method produces silver halide grains with a narrow diameter distribution. Based on this technology, the present inventors have continued to conduct intensive studies on production equipment for silver halide grains with a narrower particle size distribution and production equipment suitable for producing a large amount of silver halide grains. It has become clear that silver halide grains with a narrow diameter distribution can be achieved by increasing the rotational speed of the stirring blade in the mixer and increasing the amount discharged from the mixer conduit. However, when the discharge rate from the mixer conduit is increased, the crystal, which is generally called a spindle type crystal, has only one twin plane, and the interface with the dispersion medium is the (1,0,0) plane. , (1,1,1) planes, or a mixture of these planes, it was found that irregularly shaped silver halide crystal grains were generated, and a uniform silver halide grain crystal habit could not be obtained. An object of the present invention is to improve the techniques shown in FIGS. 1, 2, and 3, and to produce silver halide grains with a narrower grain size distribution and uniform grain crystal habit. An object of the present invention is to provide an apparatus for producing a silver photographic emulsion. Another object of the present invention is to provide an apparatus for producing a silver halide photographic emulsion, which facilitates the production of silver halide grains in large quantities. The above-mentioned object of the present invention is to have a mixer consisting of a stirring blade and a casing fixed around the stirring blade in a reaction vessel, and the casing has a lower end portion containing a halogen salt aqueous solution, a silver salt aqueous solution, and a protective colloid aqueous solution. It has an opening for introducing the silver halide particles into the mixer, and has an opening at the upper end for discharging the silver halide particles generated in the mixer, and the upper end opening allows the liquid flow to be discharged from the stirring blade rotating shaft. In a silver halide photographic emulsion production apparatus comprising a plurality of conductive paths opening in the direction of the stirring blade rotation axis and having a sufficient length in the direction of the rotation axis of the stirring blade to create a vertical flow in the direction, the cross-sectional area of the conduction path is defined as the conduction path. This is achieved by a silver halide photographic emulsion producing apparatus in which a circumferential flow component is added to the liquid flow discharged from the conduit passage by increasing the flow rate continuously toward the upper opening. Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic sectional view of a silver halide photographic emulsion manufacturing apparatus showing one embodiment of the present invention, FIG. 4 is a plan view of the upper end of the mixer 2, and FIG. FIG. 4 is an enlarged longitudinal cross-sectional view taken along FIG. 4a-a. The aqueous halogen salt solution and the silver salt solution are continuously supplied to the lower end of the mixer 2 provided in the reaction vessel 1 through supply pipes 3 and 3', respectively. A reaction vessel 1 is filled with an aqueous protective colloid solution, a mixer 2 is provided below the surface of the aqueous protective colloid solution, and the inside of the mixer 2 is filled with the aqueous protective colloid solution. The protective colloid aqueous solution in the reaction vessel 1 is always caused to convect by the action of the mixer 2 so as to cross the inside of the mixer 2 from the bottom to the top. The mixer 2 has an opening with a circular cross section at the lower end 21 of a cylindrical casing, and has a conduction path 6 that opens only in the direction of the stirring blade rotation axis 5 at the upper end of the cylindrical casing. The conduit 6 has a sufficient length in the direction of the stirring blade rotation axis 5 to make the discharge flow vertical. Although the length of the conductive path varies depending on the specifications of the device, it is preferable that the ratio of the length of the conductive path to the area of the opening of the conductive path is in the range of 0.01 or more. The conductive path 6 has a circular cross section at the lower opening 61, but the cross sectional area continuously expands from the intermediate point b toward the center of the adjacent conductive path, and at the upper opening 62, the cross section becomes semi-elliptical. It is the shape. The amount of increase and continuous change in the area of the upper opening of the conductive passage 6 from the area of the lower opening cannot be determined unconditionally, and it depends on the discharge amount from the conductive passage 6 or the internal volume of the mixer 2. 6
Any configuration may be used as long as it adds a component in the circumferential direction of the stirring blade rotation axis to the vertical flow discharged from the stirring blade. The mixer 2 is provided with pitched paddle type stirring blades 4 attached to a vertical rotating shaft 5.
The stirring blade 4 rapidly stirs both reaction liquids supplied to the opening of the lower end 21 of the cylindrical casing through the supply pipes 3 and 3' after the reaction liquids are diluted with the protective colloid aqueous solution in the mixer 2. mix,
Silver halide particles are generated, and the protective colloid aqueous solution in the reaction vessel 1 is immediately discharged from the conduit 6 to the outside and above of the mixer 2. The silver halide photographic emulsion manufacturing apparatus used in the present invention is not limited to the configuration shown in FIGS. 1, 4, and 5, but various modifications may be made within the scope of the claims. It goes without saying that this is possible. Further, in the present invention, it is advantageous to use a flow control plate immediately below the surface of the protective colloid aqueous solution above the mixer 2 because the discharge circulation flow rate discharged from the conduction path 6 can be increased without causing foaming. It is use. In the present invention, the silver halide particles produced in the mixer are discharged outside the mixer along with the discharge flow of the stirring blade, and then circulated within the reaction vessel and recycled back to the mixer. In the process of growing silver halide grains through the repetition of this recycling movement, in order to shorten the cycle of the recycling movement of individual silver halide grains and to reduce the period difference between grains, When the discharge rate is increased, irregularly shaped silver halide particles, which occur due to a decrease in the residence time of the circulation flow inside the mixer, can be eliminated by uniform vertical discharge from the conduction path without expanding the internal volume of the mixer. This was realized by a silver halide photographic emulsion manufacturing apparatus having an upper opening of a conduit passage configured to add a circumferential flow component to the flow to supplement the stirring and mixing in the mixer. When the present invention is applied to the so-called single-jet method, double-jet method, or controlled double-jet method, the reaction in the mixer can be carried out quickly and completely. By maintaining the amount added at approximately the same amount, it is possible to maintain the silver ion concentration in the dispersion (aqueous protective colloid solution containing suspended silver halide particles) at a preset value relatively easily. It has extremely great advantages in the production of silver halide photographic emulsions. Hereinafter, the effects of the present invention will be illustrated by specific examples. Example The following three types of solutions were prepared. Solution [A] Gelatin 600g NaCl 2.5g Add water to make 15000c.c. Solution [B] NaCl 1170g Add water to make 10000c.c. Solution [C] AgNO ₃ 3400g Add water to make 10000c.c. The manufacturing apparatus used had the configuration shown in FIGS. 1, 4, and 5. That is, a hemispherical bottom cylindrical reaction vessel (diameter 400 mm) was filled with solution [A], and solutions [B] and [C] were passed through tubes 3 and 3' at a constant rate (166
cc/min) separately and continuously. The mixer has a cylindrical casing with a diameter of 80 mm and a height of 70 mm, the lower end 21 is open with a diameter of 30 mm, and the upper end conduction path 6 has a circular lower opening 61 with a diameter of 25 mm and a length of 0 mm in the vertical direction. The cross-sectional area increases continuously from point b 5 mm below the upper opening 62 toward the center of the adjacent conductive path, and the upper opening 62 has a long diameter.
It is a semi-elliptical joint shape with a short diameter of 30 mm and a short diameter of 25 mm. The stirring blade 4 was a 45° pitched paddle with a blade length of 20 mm, and was rotated at a rotation speed of 1500 rpm. On the other hand, a comparative experiment was conducted in the case where the cross-sectional area of the conductive path was constant and the upper opening 62 was made circular with a diameter of 25 mm in the above embodiment of the present invention. The silver halide grains thus obtained were measured for average grain size, standard deviation, and number of irregularly shaped grains using electron micrographs. The results are in Table-1
It was hot on the street.

[Table] Most of the silver halide grains in the comparative experiment were crystals having (1,0,0) planes, but the irregularly shaped grains were clam-shaped crystals. As is clear from the above description, the following effects can be obtained by the present invention. (1) By adding a circumferential flow component to the vertical flow discharged from the mixer by using a conductor passage whose upper opening area is larger than the lower opening area, It is possible to produce a silver halide photographic emulsion with a narrow grain size distribution and a uniform crystal habit by supplementing stirring and mixing to prevent the generation of irregularly shaped silver halide grains. (2) By increasing the circulation flow rate discharged from the mixer, the problem of poor circulation on a large scale is solved, and it becomes possible to produce a large amount of silver halide photographic emulsion. (3) Since silver halide with a narrow grain size distribution and uniform crystal habit can be produced, it is possible to improve photographic performance, and in particular to save silver.

[Brief explanation of drawings]

1 is a schematic longitudinal sectional view of a device according to the prior art and according to the invention; FIG. 2 is an enlarged longitudinal sectional view of a mixer portion according to the prior art; and FIG. 4 is an enlarged plan view of the mixer section of the apparatus according to the invention, and FIG. 5 is an enlarged longitudinal sectional view of the mixer section of the apparatus according to the invention taken along the line a--a in FIG. In the figure, 1 is a reaction container, 2 is a mixer, 21 is a lower open end, 3 and 3' are reaction liquid supply pipes, 4 is a stirring blade,
Reference numeral 5 indicates the rotation shaft of the stirring blade, 6 indicates the conduit passage, 61 indicates the lower opening of the conduit passage, and 62 indicates the upper opening of the conduit passage.

Claims (1)

[Claims] 1 A mixer consisting of a stirring blade and a casing fixed around the stirring blade is provided in the reaction vessel, and the casing has an opening at the lower end for introducing a halogen salt aqueous solution, a silver salt aqueous solution, and a protective colloid aqueous solution into the mixer. The upper end has an opening for discharging the silver halide particles generated in the mixer, and the upper end opening allows the liquid flow to be discharged to be a vertical flow in the direction of the rotation axis of the stirring blade. In a silver halide photographic emulsion manufacturing apparatus comprising a plurality of conductive passages that have a sufficient length in the direction of the rotation axis of the stirring blade and are open in the direction of the rotation axis of the stirring blade, the cross-sectional area of the conduction passage is defined as the upper opening of the conduction passage. 1. An apparatus for producing a silver halide photographic emulsion, characterized in that a circumferential flow component is added to the liquid flow discharged from the conduction path by increasing the flow rate continuously toward .