JP2670877B2 - Method for producing silver halide emulsion - Google Patents

Description

TECHNICAL FIELD The present invention relates to a silver halide emulsion useful in the field of photography, and more particularly to a method for producing monodisperse silver halide emulsion grains having a narrow grain size distribution width.

(Prior Art) In order to produce monodisperse silver halide emulsion grains having a narrow grain size distribution width, it is necessary to grow crystals of the silver halide emulsion grains under high supersaturation conditions. As a method therefor, Japanese Patent Publication No. Sho 48-36890 and Japanese Unexamined Patent Publication No. Sho 48-8660 propose a flow rate accelerated addition method in which the flow rate of the solubilizing solution is increased with the addition time. However, this method has a disadvantage that the total amount of the added liquid remarkably increases with the addition time. In order to improve this, U.S. Pat.No. 4,242,445, JP-A-55-158
No. 124 proposes a method of increasing the concentration of the addition solution with the addition time. In this method, the disadvantage that the total amount of the added liquid increases remarkably with the addition time is solved, but there is a problem in that the addition rate of the solute can be increased continuously and accurately with a simple device. . In order to continuously increase the concentration, a concentrated solution is added to the dilute solution by controlling the flow rate, equipment for stirring the solution and a device for controlling the addition flow rate of the solution are required, which makes the device complicated. And the accuracy is not good. For example, when a concentrated solution is added to a dilute solution, a certain period of time is required until both solutions are uniformly mixed. Also, at this time,
Since the solution concentration added from the addition port has a complicated function as described in Reference 1, which will be described later, the corresponding calculation is troublesome. In the system in which the diluting liquid and the concentrated liquid are mixed and added in the middle of the addition system tube, two addition systems and the flow rate control system are required for one solution addition system, which complicates the apparatus. The patent states that the concentration increasing method and the flow rate accelerating method can be used in combination, but there is no specific description on how to use them together. Therefore, it has been desired to develop a highly accurate and simple accelerated addition method for solutes, which solves both the drawbacks of the flow rate accelerated addition method and the drawbacks of the concentration acceleration method. Further, it is desired to develop a method and an apparatus for producing a silver halide method emulsion in which a solute which is controlled and added with high precision is uniformly added to a reaction solution, and variation in supersaturation degree in the reaction solution is small. .

(Problems to be Solved by the Invention) An object of the present invention is to eliminate the drawbacks of the flow rate acceleration method as described above.
Moreover, the drawbacks of the concentration increasing method are eliminated, and the addition rate of the solute can be increased continuously and accurately with a simple apparatus, and therefore, crystal growth can be performed with high accuracy and under high supersaturation conditions. Another object of the present invention is to provide a method for producing silver halide emulsion grains, which is capable of producing monodispersed silver halide emulsion grains rapidly.

(Means for Solving the Problems) The object of the present invention is (1) a silver halide emulsion having a step of accelerating addition of at least a silver salt and a halogen salt with an addition time to an aqueous dispersion medium solution containing at least water and a dispersion medium. In the method for producing particles, the accelerated addition is performed by at least two steps of substantially double jet addition of a silver salt solution and a halogen salt solution, and within the step, accelerated flow addition is performed.
The flow rate acceleration rate (final flow rate of the step / initial flow rate of the step) is 1.1 to 20, and the concentration of the added solution is increased between adjacent steps.
A method for producing a silver halide emulsion, characterized in that

(2) The method for producing a silver halide emulsion according to (1) above, wherein the accelerated flow rate addition is performed according to the following formula.

In the formula, y is the addition rate, K is 4πN (N is the total number of particles), n is an arbitrary value between 0.3 and 0.97, r is the particle radius, and dr / dt is the critical growth rate.

(3) The method for producing a silver halide emulsion according to the above (1) or (2), wherein the accelerated flow rate addition is carried out by a capacity control type addition device.

(4) The method for producing a silver halide emulsion as described in the above items (1) to (3), wherein the flow rate accelerating addition is carried out by a plurality of alternating volume control type pumps.

 Hereinafter, the present invention will be described in detail.

(Basic idea of the invention) The main points of this manufacturing method are as follows. "For frequent small accelerated addition of solute (eg continuous flow accelerated addition) with respect to the addition time, the accelerated flow addition method is superior, so the accelerated flow addition method is used. For example, an acceleration signal is given to the plunger of the plunger pump. When the plunger is lowered, the signal immediately gives an increase in the flow rate from the addition port according to the principle of Pascal, that is, the quick response is good, and when the plunger is lowered according to a complicated relationship. The solution added according to Pascal's principle is also very promptly added according to the complicated function of the solution, such as the concentration increasing method, in which a thick solution and a thin solution are uniformly mixed and then sent. Because there is no time consuming process of adding, but continuing to accelerate the flow rate greatly increases the total reaction solution volume, since it is Compared with this, the amount of reaction solution increases by the amount of accelerated flow rate.Therefore, in order to avoid this, the step is changed and the initial flow rate is decreased by using a more concentrated reaction solution to accelerate the next flow rate. At this time, if a plurality of adding devices are used, the next thicker solution can be prepared while adding with one device, so that the problem of waiting time can be avoided. In the present invention, the production of silver halide emulsion grains is 2
The process of substantially double jet addition of the silver salt solution and the halogen salt solution is carried out over the above steps.

Here, “substantially” means that the double jet method in which the addition of the halogen salt aqueous solution is preceded by 1 minute is included. It is preferable that 70% or more, and more preferably 90% or more, be added at the same time.

Here, the flow rate acceleration rate in each step = (final flow rate of the step / initial flow rate of the step) is 1.1 to 20, preferably 1.2 to 10, and more preferably 1.3 to 5. When the amount is 20 times or more, the total reaction solution amount is greatly increased, which is not preferable. The smaller the magnification, the better. This is because the total reaction solution volume is less increased and the production efficiency is increased. That is, when using a reactor having the same volume, a larger amount of silver halide emulsion can be produced, it can be used in the addition flow rate region most suitable for the addition system, and the total amount of solution added in one step is Less, for example, the cylinder capacity of the adding plunger pump can be reduced,
This is because it is possible to further reduce the size of the addition device, avoid an excessive pressure load on the addition system, and improve safety.

The rate of increase in the solution concentration between adjacent steps (concentration mol of the addition liquid added in the subsequent step / liter / concentration mol of the addition liquid added in the previous step / liter) is 1.
1 to 20 times, preferably 1.2 to 10 times, more preferably 1.3 to
5 times. This is because, as the flow rate acceleration rate decreases, the concentration increase rate decreases accordingly.

In the present invention, the production of AgX emulsion grains comprises the steps of having the above-mentioned characteristics in two or more steps, preferably three or more steps, more preferably 3 to 20 steps, further preferably 4 to 16 steps. Substantially double jet addition process. In this case, for example, a system in which a constant velocity double jet addition of the silver salt aqueous solution and the halogen salt aqueous solution (that is, double jet addition not having the above characteristics) is included in the step is also included in the present invention. That is, two or more steps having the above characteristics are included, but steps without the above characteristics may be interrupted. However, since it only serves to make the effect of the present invention smaller, it is preferably not included. Further, the switching of each step can be performed in such a manner that the end part of the previous stage and the initial part of the next stage overlap.
In this case, as described in Japanese Patent Application No. 63-22842, an embodiment in which the total addition rate of both solutes is controlled is more preferable.

The silver halide emulsion construction method of the present invention is particularly effective when the solute addition rate is continuously increased with the addition time. In this case, it is necessary to obtain in advance what kind of continuous function to increase, and to input the function into the system controller of FIG. Regarding the method of obtaining the continuous function, the description of Japanese Patent Application No. 63-223739 by the present inventor can be referred to. A brief description is as follows.

The critical growth rate that changes with the growth of AgX particles is experimentally obtained as a function f (r) of the particle radius r, And put. Transform this By calculating the inverse function r = F (t), the rate of addition of the solute with respect to the addition time (y) is expressed as Can be obtained by Here, K is a constant (K = 4π
N is the total number of particles). If r and the initial addition rate (yo) at t = 0 are determined, K can be determined.

More simply, graphing equation (2) for any r ₁ , r ₂ ,
Determine r ₃ ... And read the corresponding values of t ₁ , t ₂ , t ₃ ... From the graph. On the other hand, the corresponding y ₁ , y ₂ ,
y ₃ ... (If r is determined, read dr / dt from the graph. K is known), make a table of y vs.t, write a graph of y vs.t based on the table, and draw the graph. Y = G (t) is obtained by functionalizing.

G (t) Then, for example, simply And three representative points (y ₀ , t ₀ ) on the graph,
By selecting (y ₁ , t ₁ ) and (y ₂ , t ₂ ) and substituting them into equation (4), the respective constants of A, B, and C can be obtained. However, when a solute is added in accordance with the critical addition rate curve thus determined, it is highly likely that a new nucleus is generated due to a slight fluctuation of stirring or the like. Therefore, normally, the critical growth rate n
The AgX particles are grown at a double (n = 0.97-0.3) growth rate.

In this case, it is sufficient to solve by multiplying f (r) in the equation (1) by n. That is, equation (3) is Becomes

In this way, the graph of equation (3) or equation (3 ′) y vs. t corresponding to it can be obtained. yv
In general, the graph of st can often be approximated by combining two or three straight lines. Therefore, for convenience, it is possible to
Crystals can be grown according to the straight line increasing method according to three straight lines.

As the pump for accelerating the flow rate, a gas pressure addition system (a method of applying pressure to the addition solution by air or N ₂ and controlling the flow rate according to the Hagen-Poiseuille equation through one or more holes, that is, By changing the pressure difference ΔP on both sides of the hole, the effective area of the hole, or both,
A method of controlling the flow rate), a gear pump, a plunger pump, a diaphragm type pump or the like can be used. Regarding these, Japanese Patent Application No. 1-28862, edited by the Society of Chemical Engineers, "Chemical Equipment Handbook", Chapter 18, published by Maruzen (1989),
Reference can be made to Japanese Patent Application No. Sho 63-22842, "Encyclopedia of Chemical Equipment", Chapter 1, published by Kagaku Kogyo Co., Ltd. (1976), and FIGS.

However, in general, the flow rate control accuracy is higher when the flow rate is controlled by the amount of liquid actually added than by the physical quantity related to the flow rate. For example, when the above ΔP value is controlled to control the flow rate, there is no guarantee that the flow rate is really set. For example, the following specific examples can be given. When the fluid passes through the pores at a high speed, Bernoulli's theorem causes the pores to be in a depressurized state, which is likely to occur. When the pore portion plays the role of a zeolite, adhered bubbles are generated in the pore portion, which causes a flow rate error. When the liquid surface height of the added solution changes, the ΔP value is changed by the siphon principle. When the affected reaction solution is vigorously stirred, the pressure in the vicinity of the stirring is reduced by Bernoulli's theorem. When the addition port is installed in the vicinity, the ΔP value is affected. Since the stirring flow is not a laminar flow but a turbulent flow, the depressurized state is a random unsteady state. Therefore, the flow rate is randomly disturbed. At the start of addition
A phenomenon called "overshoot" may occur in which the flow rate exceeds the set flow rate.

In addition, there is also a method of measuring the flow rate of the solution flowing through the addition tube and controlling the flow rate as (addition flow rate = flow rate × cross-sectional area of the tube). However, the flow velocity of the liquid flowing through the tube is not uniform, and the flow velocity decreases as approaching the tube wall, and the above equation does not hold strictly. Also, when turbulent flow enters,
The flow velocity value becomes an incorrect value. Therefore, these flow rate control methods are not preferable.

On the other hand, for example, when the plunger is pushed into the cylinder by the plunger pump, if it is controlled by (displacement position / time of the plunger), (displacement amount of the plunger = added liquid amount). Exactly (addition amount / time) is controlled. Therefore, as a flow rate control method, a control method (volume control type addition device) based on an easy factor (actually added liquid amount) is more preferable than a control method based on a strength factor (ΔP value or flow velocity value described above). preferable. Specifically, for example, in the case of the plunger pump shown in FIG.
A pulse motor is used for the drive unit 15. Pulse motor 15
When driven by 1 pulse, for example, it rotates by a rotation angle of 1 ° and pushes down the plunger 3 by 1 pulse through the shaft 18 with a screw for power transmission [For details, see "Mechatronics Practical Handbook", supervised by the Mechatronics Committee). You can refer to the description in Chapter 9, Issued by the Technical Research Committee (1983)]. Then, a solution amount corresponding to one pulse is added. The amount of added liquid per pulse can be arbitrarily selected according to the production level. Usually 50-500
In the reaction container of 0.1 to 100 ml / pulse region. The number of pulses during the addition is preferably 200 to 0.02 pulse / sec, more preferably 50 to 0.1 pulse / sec.

Next, the present invention will be described more specifically with reference to FIG. 1, which is a preferred embodiment of the present invention. 1 is a homogeneous solute solution and 2 is the container. 3 is a plunger of the plunger pump, and 4 is the cylinder. Reference numeral 5 is a suction / drainage switching valve of the plunger pump, and 6 is an air vent switching valve for the air in the cylinder. First, the homogeneous solute solution is put into the container 2, and the valve 6 is closed. The valve 5 is opened to the solution 1 side, the plunger of 3 is raised, and the solution is sucked into the cylinder 4. The valve 5 is closed, the valve 6 is opened to the 7 side, the plunger is lowered, and the air in the cylinder is discharged from 7 through the valve 6. Next, the valve 6 is closed, the valve 9 is opened, and the solution is added through the addition port 20.

Frequent fine-accelerated additions (eg, continuous flow-accelerated additions) to the addition time are done by flow-accelerated additions during this period. In this case, when a signal for accelerated addition is applied to the plunger and the descending speed of the plunger increases, it immediately becomes a flow rate increase from the addition port 20 due to the principle of Pascal, and the prompt response of signal transmission is very good. Therefore, this method is suitable for frequent and fine accelerated addition of solute with respect to the addition time. However, when the solution is added, the flow rate of the addition solution at the addition port is preferably higher than the rate at which the reaction solution 10 flows backward from the addition port 20 due to molecular diffusion, and therefore a flow rate lower than that is preferable. Absent. Generally, a flow rate of V> 10 cm / min is preferable, and V> 30 cm / min is more preferable.

On the other hand, the high flow velocity side is restricted because the pressure applied to the addition system becomes too large and the addition liquid amount becomes too large. Therefore, V <
It is preferably 4000 cm / min or less, more preferably V <1500 cm / min.

The addition port 20 has 100 pores of 0.15 mmφ, which are evenly scattered on the inner wall side on one side of the bottom surface of the chamber, the addition port 21 is the same addition port, and when 20 is an X ^- salt addition system, 21 Is an Ag ⁺ salt addition system.

While the addition solution is being added to the reaction solution 10 using the addition system of A in this manner, the addition solution of the next step is placed in the second container. The valve 6'is closed, the valve 5'is opened to the solution 1 side, the plunger 3'is raised, and the solution is sucked into the cylinder 4 '. The valve 5'is closed, the valve 6'is opened to the 7'side, the plunger 3'is lowered, and the air in the cylinder is discharged from 7'through the valve 6. Close valve 6'and wait. When pump A addition is complete, valve 9 is closed, valve 9'is opened and pump B solution addition is started. While adding the B side, the A side is washed and the next addition solution is put in the system, that is, when the valve 6 is opened to the 7 side and the valve 5 is opened, air is released from 7 Enter, and the residual solution of the A addition system is in container 1
Is discharged. Since the discharge amount is fixed, the next added solution is put into the container 2 and stirred to obtain a liquid having a predetermined concentration. The valve 6 is closed, the plunger 3 is raised, and the solution is sucked into the cylinder 4. After that, the above steps are repeated until silver halide grains having a desired size are obtained. When it is desired to wash the addition system, the drainage solution, the valve 6 is closed, the plunger 3 is raised, water is sucked from 8 and then the plunger 3 is lowered and drained from 8 or Close 5,
The plunger 3 may be lowered, the valve 6 may be opened, and the liquid may be drained from 7. If further washing is desired, this may be repeated. The second container can also be washed and then filled with fresh solution. In addition, stop adding pumps A and B, and
It is also possible to open between 12 and drain the solution in the tube from 12. Further, when the concentration of the solution and the halogen composition are not largely different and mixing of the residual liquid is allowed, the residual liquid can be continuously operated without draining. In addition, when the waiting time before the addition of A is completed after the addition of A is completed, the valve 13 is switched to the 12 side, the solution between 13 and 20 is added at a constant speed, and the space between 13 and 20 is emptied. It is preferable to wait. valve
By choosing 13 or 12 aperture diameters, or 12
The flow rate can be controlled by controlling the applied pressure.

In addition, as the plunger pump, A in FIG.
Only one may be used repeatedly. In this case, there is an advantage that the equipment is simplified, but there is also a disadvantage that a waiting time is inserted between steps.

The plural alternating pumps referred to in the present invention refer to pumps having two or more such capacity control type pumps, and preferably to pumps having two to three groups.

Reference numeral 11 in FIG. 1 denotes a shield packing, which is usually made of an organic polymer material or its composite material (for example, Teflon on the surface and silicone rubber on the inside) which is inert to the added solution and has elasticity. Used. Regarding this, edited by The Chemical Society of Japan, "Handbook of Chemistry", Chapter 10, published by Maruzen (1980), edited by The Polymer Society of Japan, one point new polymer material
-19, "Elastomer" published by Kyoritsu Publishing (1989), Hideo Kaneko, "20 lectures on applied rubber physical properties" published by Taiseisha (1978) can be referred to. In general, 11 is less likely to be scratched by an elastic body such as rubber.

Reference numeral 19 is a mixing chamber, which can be referred to the description in JP-A-51-72,994. Reference numeral 17 is a system controller. The system controller is used to control the opening and closing of various solution valves, start and stop of stirring, metering of solutions, start and stop of suction and addition, flow rate control, start and stop of CDJ control, etc. It refers to a control device that sequentially and systematically adjusts according to the order. As a control device, a general one can be used. For details, refer to the description of "Sequence Automatic Control Handbook" by Ohmsha (1971), supervised by Zensaburo Sawai. Therefore, in FIG. 1, the control of each switching valve and each on-off valve is performed systematically in accordance with a command from the system controller 17 (that is, in accordance with a program input in advance).

Reference numeral 15 is a drive unit, which includes a speed reducer and a pulse motor. A pulse motor, a DC servo motor, or an AC servo motor can be used as the motor, but the pulse motor is more preferable as described above. Reference numeral 18 denotes a power transmission shaft, specifically, a shaft having a feed screw on the surface. The pitch of the screw is determined according to the outflow rate of the added solution and the control accuracy.

When it is desired to continuously change the halogen composition as the crystal grows, another addition system may be provided in the halogen salt aqueous solution addition system, and the embodiment shown in FIG. 2 may be used. The halogen composition can be continuously changed by continuously changing the flow rate ratio of X ₁ and X ₂ . Where x ₁
And X ₂ represent halogen salt aqueous solutions having different halogen compositions.

When the halogen composition is to be changed sharply, an aqueous solution of a halogen salt having a different halogen composition may be used between steps.

As the material of the liquid contact part of the reaction vessel or pump, an inert material that does not react with the added solution is preferable, and specifically, other than organic polymer materials such as polyethylene, polypropylene and Teflon, hard glass, Stainless steel (SUS316,
316L, 329J), and composite materials thereof (for example, stainless steel coated with Teflon). Further, in order to reduce the thermal expansion error due to temperature fluctuation, the room temperature of the addition system may be kept constant at, for example, 23 ± 2 °.

Other examples of the capacity control type liquid feed pump include a diaphragm type pump. Since the diaphragm pump does not have a shield part and is a closed system, it has an advantage of never causing air leakage or liquid leakage. Further, since there are no portions that are in rubbing contact with each other, troubles due to scratches due to dust or the like do not occur. Therefore, in these respects, the diaphragm pump is more preferable. Specifically, the third
An example is a serpentine membrane pump as shown in the figure. In FIG. 3, a and b are bent portions, and rubber elastic bodies (elastomers) are used. Regarding the rubber elastic body, the description in FIG. 1 and FIG. 11 can be referred to.

It is preferable that the added solution added to the reaction solution is rapidly and uniformly mixed into the reaction solution. The solute ion inhomogeneity in the reaction solution is reduced, and the intergranular heterogeneity of AgX growth and A
Non-uniformity of gX composition can be reduced. Further, it is possible to grow at a high supersaturation without generating new nuclei, and it is possible to rapidly prepare AgX emulsion grains having better monodispersity. Therefore, it is preferable that the addition solution is directly added to the reaction solution (that is, directly added below the liquid surface) and vigorously stirred by a stirring blade installed near the addition port. Regarding these addition systems, stirrers and reaction vessels, baffles, and stirring blades, Research Disclosure, Volume 166, No. 16662 (1978)
February), U.S. Patents 3,897,935, 3,790,386, 3,
415,650, 3,692,283, 4,289,733, 3,785,7
No. 77 each specification, JP-A-57-92524, 60-117834,
Reference can be made to the descriptions in JP-A-62-182623, Japanese Patent Application No. 1-207513, and JP-A-1-258862 or each specification.

When the addition is performed through the porous body addition system, the solute concentration becomes more non-uniform, and uniform growth with higher supersaturation can be achieved. Therefore, it is more preferable. For the details, the description in Japanese Patent Application No. 1-76678 can be referred to. The solute addition method of the present invention is described in Japanese Patent Application No. 1-258862.
No. 2-188243, No. 2-142635, the production apparatus and the production method can be preferably used.

As a method for adding the solute, fine silver halide emulsion grains having a diameter of 0.15 μm or less prepared in advance can be used in addition to an aqueous solution of a silver salt or an aqueous solution of a halide salt. The silver halide grains refer to AgCl, AgBr, AgI and mixed crystals of two or more thereof. The fine particles may be prepared immediately before in the container 2 shown in FIG. It is preferable because problems such as storage stability of fine grain silver halide can be solved. When the fine particles are prepared near room temperature (15 to 35 ° C.), it is preferable to use low molecular weight gelatin that does not gel even in the temperature range. As the low molecular weight gelatin in this case, gelatin having a molecular weight of 100 to 100,000, preferably 3000 to 70,000 is used.
Gelatin containing 30 to 100% by weight, preferably 50 to 100% by weight is preferred.

In addition, gelatin can be contained in the silver salt aqueous solution and / or the halogen salt aqueous solution. Regarding this, Japanese Patent Application Nos. 63-315741, 63-223739, and Japanese Patent Application No. 63-11
The description of No. 928 can be referred to.

The nucleation of the silver halide emulsion manufacturing method of the present invention is as follows. Regarding the nucleation conditions of non-twinned particles, the description in Japanese Patent Application No. 63-223739 is given, and regarding the nucleation of monodisperse parallel double twinned particles, Japanese Patent Application No. 63-315741 and Japanese Patent Application No. 1-90.
The description of No. 089 can be referred to for the nucleation of other particles, and the description of the following documents can be referred to.

The silver halide emulsion grains that can be produced by the method for producing a silver halide emulsion of the present invention include tabular grains having parallel twin planes and normal grains having no twin planes (eg, cubic, tetradecahedral, octahedral). Other, rhombohedral dodecahedron,
It can be used as a grain forming method for all existing AgX grains such as trioctahedral, rhomboid icosahedron, tetrahedron and hexaoctahedral grains. The halogen composition is not particularly limited, and Ag
It can be used for Cl, AgBr, AgI and mixed crystals thereof. The particle size is 0.05 μmφ or more, preferably 0.
It can be used as a method for producing all silver halide grains having a diameter of 1 to 5 μm. Regarding these, the description in the following literature can be referred to.

As the dispersion medium used when producing a silver halide emulsion, those commonly used for silver halide emulsions can be used, and various hydrophilic colloids such as gelatin can be used. Usually, gelatin is preferred, and in addition to alkali-processed gelatin, acid-processed gelatin, derivative gelatin such as phthalated gelatin,
Low molecular weight gelatin (molecular weight of 200,000 to 100,000, enzyme-decomposed gelatin, acid-alkali hydrolyzed gelatin) can be used, or a mixture of two or more thereof can also be used.

For details of these, reference can be made to the descriptions in the literature described below.

In order to control the degree of supersaturation during the nucleation of the silver halide grains, to accelerate the ripening in the ripening process, and to accelerate the growth in the crystal growth process, and after the grain formation and / or
Alternatively, a silver halide solvent can be used in order to effectively smooth the chemical sensitization during the chemical sensitization.

Examples of the silver halide solvent often used include thiocyanate, ammonia, thioethere and thioureas. About this, the description of the literature mentioned later can be referred to.

There are no particular restrictions on the additives that can be added during the production of the silver halide emulsion of the present invention from the time of grain formation to the time of coating. Additives that can be added are silver halide solvents (also called ripening accelerators), dope agents for silver halide grains [group 8 noble metal compounds, other metal compounds (gold,
Iron, lead, cadmium, etc.), chalcogen compounds, SCN compounds, etc.], dispersion media, antifoggants, stabilizers, sensitizing dyes (blue,
Green, red, infrared, panchromatic, ortho, etc.), supersensitizers,
Chemical sensitizer (sulfur, selenium, tellurium, gold and Group 8 noble metal compounds, phosphorus compounds alone or in combination thereof, most preferably a chemical sensitizer comprising a combination of gold, sulfur and selenium compounds , First chloride
Reduction sensitizers such as tin, thiourea dioxide, polyamines and amine borane type compounds), fogging agents (organic fogging agents such as hydrazine compounds, inorganic fogging agents), surfactants (foaming agents, etc.), emulsion precipitation Agent, soluble silver salt (AgSC
N, silver phosphate, silver acetate, etc.), emulsion precipitation agent, latent image stabilizer,
Pressure desensitizers, thickeners, hardeners, developers (hydroquinone compounds, etc.), development modifiers, etc. For specific compounds and methods of use, refer to the descriptions in the following documents. You can

In addition, the AgX emulsion can use any known combination of known techniques and known compounds described in the following documents.

Research Disclosure
e) Volume 176 (No.17643) (December, 1978), Volume 184 (No.18431) (August, 1979), Volume 216 (No.21728)
(May, 1982), "Hitachi Kyodo Monthly Report," December 1984, 18-27.
P., "Journal of the Photographic Society of Japan", Volume 49, pp. 7-12 (1986),
Volume 52, pages 144-166 (1989), JP-A-58-113926-1139
28, 59-90842, 59-142539, 62-253159, 62
-99751, 63-151618, 62-26251, 62-115035,
63-305343, 62-269958, 61-112142, 56-50
1776, Japanese Patent Application Nos. 63-223739, 63-315741, and 61-10977
3, the same 62-54640, the same 62-263319, the same 62-208241, the same 63-
129226, JP-A-1-131541, US Patents 4,705,744, 4,7
07,436, TH James, `` The Theory of The Photographic
Process (Fourth Edition) "Macmillan, New York, 197
7, VL Zelikman et al. `` Making and Coating Photogr
aphic Emulsion (The Focal Press, 1964) ", P. Glafki
des, Tchimie et physiques Photgraphiques "Fifth Edi
tion de l′ Usine Nouvelle, Paris, 1987, Second Edi
tion Paul Montel, Paris, 1957, KRHoilister, "Jour
nal of Image.Sci. " 31 , pp. 148-156 (1987). JEMask
asky, "Journal of Imaging Science" 30 , 247-254 (1986). H. Frieser et al., `` Die Grundlagen Der Ph
otographischen Prozesse Mit Silverhalogeniden "Aca
demishe Verlagsgesellschaft Frankfurt Am Main (196
8), Japanese Patent Application No. 1-76678, No. 1-258862, No. 1-1447
No. 24.

(Examples) Next, the present invention will be described in more detail with reference to Examples, but the embodiments of the present invention are not limited thereto.

Example 1 An aqueous gelatin solution (H ₂ O 1000 ml, gelatin 40
g, KBr 0.2 g, pH 5,) was added, the temperature was raised to 75 ° C., and the apparatus of the embodiment shown in FIG. 1 was stirred (the drive unit was a pulse motor and used in 0.01 ml / Pulse specifications). Using AgNO ₃ aqueous solution 1 (concentration is AgNO ₃ 0.007g / ml) and KBr aqueous solution 1 (KBr0.
0053g / ml) at 4ml / min for 10 minutes, then 24ml simultaneously
Simultaneous additions were made at a rate of 7 minutes per minute. Next, KBr aqueous solution (10 wt%
Solution) and add silver potential (against saturated calomel electrode) to -25 mV.
I made it. Next, using AgNO ₃ aqueous solution 2 (AgNO ₃ 0.1 g / ml) and KBr aqueous solution 2 (KBr 0.075 g / ml), the initial velocity was 5 ml / min at that potential.
A controlled double jet (CDJ) was added for 16 minutes with a linear flow rate accelerated addition of 0.7 ml / min. Next, AgNO ₃ aqueous solution 3 (AgNO ₃ 0.2 g / ml) and KBr aqueous solution 3 (KBr 0.145 g / ml)
With an initial velocity of 8.1 ml / min and a linear flow rate accelerated addition of 0.6 ml / min.
CDJ was added for 40 minutes. After stirring for 2 minutes, the temperature
Lower the temperature to 35 ° C, wash the emulsion with a settling water wash method, re-disperse,
The pH was adjusted to 6.2 and pBr2.8. From the TEM image of a replica of the emulsion grains, octahedral grains having an average equivalent projected grain diameter of 0.89 μm, a grain size distribution variation coefficient of 2% and a completely twin-free grain number ratio of 99.8% were obtained. That is, it was a silver halide grain having a very high monodispersity.

Here, the concentration ratio of each AgNO ₃ aqueous solution is AgNO ₃ 1: AgNO ₃ 2: AgNO ₃
It was 3≈1: 14.29: 28.57. Further, the first flow rate and a final flow rate ratio of each step in the AgNO ₃ 1 Step 1: 6, the AgNO ₃ 2 step 3.24, the AgNO ₃ 3 Step was about 4. The total amount of the added liquid was about 235 ml. When this was carried out by the simple flow rate acceleration method, the amount was about 51200 ml. However, according to the method of the present invention, the amount of the added liquid is about 4%. it is obvious.
The effect of the invention on the particle size distribution is also clear.

Example 2 aqueous gelatin solution in the reaction vessel [H ₂ O 1100 ml deionized bone gelatin 44g, NaCl0.3g, pH3] put, using the apparatus embodiment of FIG. 1 with stirring at a temperature 60 ° C., AgNO ₃ aqueous solution 1 (concentration AgNO ₃ 0.014g / ml) and NaCl aqueous solution 1 (concentration 0.05
4 g / ml) was co-added at 4 ml / min for 10 minutes. 18m in a row
Simultaneous addition was performed at l / min for 10 minutes. After stirring for 2 minutes,
59 ml of 10 wt% NaCl solution was added, and the pH was adjusted to 5 with NaOH 1N solution. Next, AgNO ₃ aqueous solution 2 (AgNO ₃ 0.09 g / ml) and NaCl aqueous solution 2 (NaCl 0.039 g / ml) were added to the initial potential of 12 ml / min and 0.3 ml / min of linear flow rate accelerated addition method at a silver potential of 80 mV for 20 minutes CDJ. Was added. Next, AgJO ₃ aqueous solution 3 (AgNO ₃ 0.18g / ml) and NaCl aqueous solution 3 (NaCl 0.07g / ml) were added to the CDJ at a silver potential of 80 mV for 30 minutes using the linear flow rate accelerated addition method at initial speeds of 9 ml / min and 0.12 ml / min. Was added.
After stirring for 2 minutes, the temperature was lowered to 35 ° C., the emulsion was washed with a precipitation washing method, redispersed and adjusted to pH 6.0 and pCl 2.56.
From the TEM image of the replica of the emulsion grains, cubic grains having an average circle-equivalent projected grain diameter of 0.73 μm, a variation coefficient of grain size distribution of 2% and a perfect twin-free grain ratio of 99.9% were obtained. That is,
The silver halide grains were very monodisperse.

Here, the concentration ratio of each AgNO ₃ aqueous solution is AgNO ₃ 1: AgNO ₃ 2: AgNO ₃
It was 3 = 1: 6.43: 12.8. Also the first flow rate and a final flow rate ratio AgNO ₃ 1 step of each step 1: 4.5, the AgNO ₃ 2 step 1.5, the AgNO ₃ 3 Step was about 1.4.

The total addition flow rate was about 1680 ml. When this is carried out by a simple flow rate accelerating method, the volume becomes about 12600 ml. According to the method of the present invention, the effect of the present invention is apparent because the liquid volume is about 13%.

(Reference 1) The case of FIG. 1 of US Pat. No. 4,242,445 will be described. The aqueous solution of silver nitrate flowing from tank A to tank B is B
Assuming that the mixture is instantly mixed to have a uniform concentration in B by the stirring operation inside, the time change of the concentration of the aqueous solution of silver nitrate flowing from B to C can be solved as follows.

Now, from A to a silver nitrate aqueous solution with a concentration of A ₀ at a flow rate of V ml / sec B
At the time t, the concentration of the silver nitrate aqueous solution in B is B (t). When the volume of the solution in _B is constantly kept at V _B ml, the increase of silver nitrate in B during the dt time is given by [VA ₀ dt-VB (t) dt). Therefore, the change of silver nitrate aqueous solution concentration in B tank during dt time Given by Transform the expression, (Effects of the present invention) 1. There is no disadvantage of the flow rate accelerating method (a defect that the total amount of the added liquid increases remarkably with the addition time), and there is no defect of the concentration increasing method (the response is good continuously with a simple apparatus). It is also possible to control the addition rate of the solute accurately and continuously according to an arbitrary function with a simple device. Therefore, crystals can be grown with high accuracy under high supersaturation conditions, and monodisperse AgX emulsion grains can be rapidly produced.

2. Since the accelerated addition of the additive solution is performed in two or more steps, the pump capacity of the addition system becomes smaller. This is because the total amount of added liquid can be increased infinitely by increasing the number of times of using the pump.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the silver halide emulsion producing apparatus of the present invention. Reference numeral 1 is an addition solution, 2 is a container, 3 and 3'is a plunger, 4 and 4'is a cylinder, 5 and 5'and 13 are three-way switching valves, 6 and 6 ', 9, and 9'are open / close valves, and 7, 7 ',
8, 8 ', 12 are exhaust port and drain port, 10 is reaction solution, 11, 1
1'is a rubber elastic packing, 18, 18 'is a shaft with a screw, 15 is a drive motor for moving the shaft up and down, its power control part and a drive part consisting of a speed reducer, 16 is a stirring blade, 17
Is a system controller. 20 and 21, respectively, hole diameter 0.15μ
The number of pores of mφ is 100 and the pores are uniformly distributed on the inner wall side of the bottom surface of one side of the chamber. When 20 is a halide salt aqueous solution addition port, 21 is an Ag ⁺ salt aqueous solution addition port. Represents an addition device when the halogen composition ratio in the effluent solution is continuously changed. X ₁ and X ₂ represent an X ⁻ salt aqueous solution having different halogen compositions. Reference numerals 6 and 6'indicate open / close valves, and A and B indicate the same plunger pumps as A and B in FIG. FIG. 3 shows an embodiment of the diaphragm pump. 1,
2, 5, 6, 7, 8, 9, 16, 18 are the same as in FIG. a,
Reference numeral b is a bent portion made of a rubber elastic body.

Claims (4)

(57) [Claims] 1. A method for producing silver halide emulsion grains, which comprises a step of accelerating addition of at least a silver salt and a halogen salt in an aqueous dispersion medium solution containing at least water and a dispersion medium with the addition time, wherein the accelerating addition is at least 2. Substantially double jet addition of a silver salt solution and a halogen salt solution in steps or more and accelerated flow rate addition in the step, and the flow rate acceleration rate (final flow rate of the step / initial flow rate of the step) is 1.1. -20, the concentration of the added solution is increased between adjacent steps, and the rate of increase in the concentration of the solution is
1. A method for producing a silver halide emulsion, which is carried out under conditions of 1.1 to 20. 2. The method for producing a silver halide emulsion according to claim 1, wherein the accelerated flow rate addition is performed according to the following formula. In the formula, y is the addition rate, K is 4πN (N is the total number of particles),
n is an arbitrary number between 0.3 and 0.97, r is the particle radius, dr /
dt represents the critical growth rate. 3. A method for producing a silver halide emulsion according to claim 1, wherein said flow rate accelerating addition is carried out by a volume control type adding apparatus. 4. The method according to claim 1, wherein the accelerated flow rate addition is performed by a plurality of alternating displacement control type pumps.
(3) The method for producing a silver halide emulsion described in (3).