JPH10197976A - Production of silver halide photographic emulsion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an emulsion consisting plate-like particles which are small in thickness and are monodisperse in the distribution of projected area diameters by specifying the ion intensity in a dispersion medium soln. during a specific stage, etc., to a specific value or above by ions exclusive of halogen ions. SOLUTION: This process includes (a) the stage for forming sliver halide particle nuclei including twin particle nuclei in the dispersion medium soln., (b) the stage for maturing the particle nuclei to allow the plate-like particle nuclei to preferentially remain and (c) the stage for growing the plate-like particle nuclei to the plate-like particles. In this process for production, the ion intensity in the dispersion medium soln. during the stage (b) or just before the stage (c) is specified to >=0.2 by the ions exclusive of the halogen ions. The dispersion medium contains at least one kind of the polymers having repeating units expressed by -(R-O)n -. In the formula, R denotes >=2 to <=10C alkylene group; (n) denotes the average number of the repeating unit and denotes >=4 to <=200.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a silver halide emulsion,
In particular, it relates to a method for producing a silver halide tabular grain emulsion for photography.

[0002]

2. Description of the Related Art Silver halide grains containing two or more twin planes in parallel have a tabular form. (Hereinafter "tabular grain")
Call. ) These tabular grains have the following photographic properties: 1) Ratio of surface area to volume (hereinafter referred to as specific surface area)
And a large amount of sensitizing dye can be adsorbed on the surface. As a result, the color sensitization sensitivity is relatively high. 2) When an emulsion containing tabular grains is coated and dried, the grains are arranged in parallel to the surface of the support, so that light scattering by the grains can be reduced and sharpness and resolution can be improved. In addition, the thickness of the coating layer can be reduced by this arrangement, and the sharpness can be improved. 3) Since the specific surface area is large, development can be accelerated. 4) High covering power enables silver saving. Because of these many advantages, they have been used in high-sensitivity commercial photosensitive materials. JP-A-58-113926
Nos. 58-113927 and 58-113928 disclose emulsion grains having an aspect ratio of 8 or more. Here, the aspect ratio is indicated by a ratio of a diameter to a thickness of a tabular grain. Further, the diameter of a particle indicates the diameter of a circle having an area equal to the projected area of the particle (hereinafter, referred to as a projected area diameter). The thickness is indicated by the distance between two parallel main surfaces constituting the tabular grains.

Further, since tabular grains having a larger aspect ratio have a larger specific surface area, the above-mentioned advantages of tabular grains can be greatly utilized. Various attempts have been made to reduce the thickness of tabular grains in order to increase the aspect ratio. Japanese Patent Publication No. 5-12696 discloses a method for preparing tabular grains having a small thickness using gelatin in which a methionine group in gelatin has been invalidated with hydrogen peroxide or the like as a dispersion medium. Japanese Patent Application Laid-Open No. 8-82883 discloses a method for preparing thin tabular grains using gelatin in which amino groups and methionine groups have been invalidated as a dispersion medium. U.S. Pat. No. 5,380,642 and Japanese Patent Application No. 7-117684 disclose a method for preparing thin tabular grains using a synthetic polymer as a dispersion medium.

Various attempts have been made to monodisperse tabular grains, and several patents have been disclosed.
For example, JP-A-52-153428, JP-A-55-142329, JP-A-51-39027, JP-A-61-112142, French Patent No.
No. 2534036. Also, JP-A-63-11928,
JP-A-63-151618 and JP-A-2-838 disclose monodisperse tabular grains containing hexagonal tabular grains. Unlike hexagonal tabular grains, these hexagonal tabular grains are monodisperse tabular grains in which the ratio of tabular grains having two parallel twin planes to the total projected area is 99.7% and the coefficient of variation of the equivalent circle diameter is 10.1%. There is a description of particles. However, tabular grains having a small thickness and a large aspect ratio have a wide distribution of projected area diameters, making it difficult to obtain a monodispersed emulsion. Meanwhile, U.S. Pat.
Nos. 1, 51,716,59, 5177772, 51,7773 and EP514742A disclose a method for producing monodisperse tabular grains by allowing a polyalkylene oxide block copolymer to be present during nucleation. ,
There is a description of monodisperse tabular grains having a coefficient of variation of 4.7%. JP-A-7-28183 and JP-A-7-98482 also disclose methods for preparing monodisperse tabular grains using a synthetic polymer. These techniques have achieved a small thickness and excellent monodispersity in the AgBr system, but it has been difficult to achieve both monodispersity and thinning in the AgBrI system.

[0005]

In view of the above, an object of the present invention is to produce an emulsion comprising tabular grains having a small thickness (ie, a large aspect ratio) and a monodisperse distribution of projected area diameters. It is to provide a way to do it.

[0006]

The object of the present invention has been attained by the following items. (1) (a) a step of forming silver halide grain nuclei containing twin grain nuclei in a dispersion medium solution; (b) a step of ripening the grain nuclei to preferentially leave tabular grain nuclei; c) a step of growing the tabular grain nuclei into tabular grains, wherein at least during the step (b) or in the dispersion medium solution immediately before the step (c), A method for producing a silver halide photographic emulsion, wherein the ionic strength is adjusted to at least 0.2 or more with ions other than halogen ions. (2) The method for producing a silver halide photographic emulsion according to the above (1), wherein the dispersion medium contains at least one kind of a polymer having a repeating unit represented by the following general formula (1). . Formula (1)-(RO) _n -wherein R represents an alkylene group having 2 to 10 carbon atoms.
n represents the average number of repeating units, and represents 4 or more and 200 or less. (3) A mixing vessel is provided outside the reaction vessel in which the nucleation step and / or the growth step is performed, and an aqueous solution of a water-soluble silver salt and an aqueous solution of a water-soluble halogen salt are supplied to the mixing vessel and mixed. The grains are formed, and the fine grains are immediately supplied to the reaction vessel, where nucleation of silver halide grains and / or
Or (1) characterized in that growth is performed.
The method for producing a silver halide photographic emulsion described in (2).

[0007] The silver halide emulsion thus obtained is a silver halide emulsion comprising a dispersion medium and silver halide grains, and has a total projected area of 80%.
% Or more is occupied by tabular grains having two or more twin planes parallel to the main plane, and the tabular grains have a hexagonal shape and the size distribution of the tabular grains is monodisperse. It is assumed that. The hexagonal tabular grains referred to in the present invention are:
Tabular grains in which the ratio of the lengths of two adjacent sides of six sides forming a hexagon are 2 or less. The thickness of the hexagonal tabular grains of the present invention is from 0.01 μm to 0.2 μm, preferably from 0.02 μm to 0.15 μm. The hexagonal tabular grains of the present invention are monodisperse, and the monodispersity referred to herein is represented by a variation coefficient of a projected area diameter. The monodispersity of the tabular grains of the present invention is a coefficient of variation of 30% or less, preferably 5 to 25%. The average aspect ratio of the hexagonal tabular grains of the present invention is from 2 to 60, preferably from 3 to 50. Here, the average aspect ratio means an average value of aspect ratios of all tabular grains having a diameter of 0.2 μm or more present in the emulsion.

When silver halide grains are formed in a dispersion medium solution, a silver salt solution (eg, silver nitrate (AgNO ₃ )) and a halide salt solution (eg, KBr, NaBr, NaCl, KI, etc.) are added to the dispersion medium solution to precipitate silver halide (AgX). At this time, a plurality of ions (NO ₃ ⁻ , K ⁺ , Na ^+, etc.) unrelated to the precipitation of silver halide remain in the dispersion medium solution. When this ion is applied to the base in the presence of a large amount and dried, the salt precipitates and exerts an adverse effect. Thus, ions are present in the dispersion medium solution in normal particle formation. However, the ion concentration changes with particle formation, that is, usually increases, so that the ion concentration is low in the early stage of particle formation and is high in the last stage of particle formation. Also,
Although a method of increasing the ionic strength by using a halogen ion is considered, it is not preferable because the solubility of the silver halide changes depending on the concentration of the halogen ion. In fact, U.S. Patent No.
In Example (2-A) of No. 5061617, 0.826 mol / liter (ionic strength: 0.248) of CaCl ₂ was added to form nuclei, but the solubility was extremely high, and favorable tabular grains were not obtained. In the present invention, it has been found that the thickness of the tabular grains is reduced in tabular grain formation by adding various ions other than halogen ions before grain formation and increasing the ion concentration (ionic strength) in advance.

Generally, ions have a positive or negative charge, and the number of charges varies depending on the type of ion. It can be defined by a value called "ionic strength" as an index showing the overall effect of the number of charges and the concentration of ions in the solution.
The ionic strength (μ) is defined as follows. _{μ = (ΣC i × Z i} 2) / 2 , where the C _i concentration of ions i, the Z _i represents the charge of the ion i. The ionic strength during grain formation and the thickness of the tabular grains generally correlated. That is, when the ionic strength was increased, the thickness of the tabular grains was reduced. Preferred ionic strength and preferred ionic species will be described later.

Next, the polymer used in the silver halide emulsion of the present invention will be described in detail. The polymer used for forming the tabular grain emulsion of the present invention is a polymer having a repeating unit represented by the following general formula (1). Formula (1)-(RO) _n -wherein R represents an alkylene group having 2 to 10 carbon atoms.
n represents the average number of repeating units, and represents 4 or more and 200 or less. In forming the emulsion of the present invention, it is preferable to use a repeating unit of the general formula (1) as long as it contains at least one monomer represented by the following general formula (2). A vinyl polymer as a component or a polyurethane represented by the following general formula (3) is preferably used, and a vinyl polymer having a repeating unit represented by the general formula (2) is particularly preferable. General formula (2)

[0011]

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General formula (3)

[0013]

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Where R^FiveIs an alkyl having 2 to 10 carbon atoms
Represents a len group. n represents the average number of repeating units, and 4 or less
Represents the upper 200 or less. R¹Is hydrogen atom, lower alkyl
Group, R ^TwoRepresents a monovalent substituent, and L represents a divalent linking group.
You. R^Three, R^FourIs an alkylene group having 1 to 20 carbon atoms,
A phenylene group having 6 to 20 carbon atoms, or a phenylene group having 7 carbon atoms
And represents an aralkylene group of 20. x, y, z are each component
X represents 1 to 70, and y represents 1 to 70.
70 and z represent 20 to 70. Where x + y + z
= 100.

Specific examples of the polymer used in the present invention are shown below, but the polymer of the present invention is not limited to these. Further detailed examples and general descriptions are described in Japanese Patent Application No. 8-113454.

[0016]

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[0017]

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[0018]

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[0019]

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[0020]

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Preferred examples of the polymer having a repeating unit represented by the general formula (1) of the present invention include polyalkylene oxide block polymers represented by the following general formulas (4) and (5). Can be General formula (4)

[0022]

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Formula (5)

[0024]

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In the formula, R ⁵ represents a hydrogen atom, an alkylene group having 1 to 10 carbon atoms, or an aryl group having 6 to 10 carbon atoms;
n represents an integer of 1 to 10. Here, when n = 1,
R ⁵ is not a hydrogen atom. R ⁶ represents a hydrogen atom or a lower alkyl group having 4 or less carbon atoms and substituted by a hydrophilic group. x and y represent the number of repetitions of each unit (number average degree of polymerization).

Specific examples of the block polymer used in the present invention are shown below, but the polymer of the present invention is not limited to these. More detailed examples,
General descriptions are given in European Patents 513722, 513723, 51
3724, 513735, 513742, 513743, 5180
No. 66, Japanese Patent Application No. 8-113454.

[0027]

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[0028]

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[0029]

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Next, the mixing container for forming silver halide fine particles used in the present invention will be described.
You can refer to the description of 7219. The mixing vessel is a stirring vessel provided with a predetermined number of supply ports through which a water-soluble silver salt and a water-soluble halogen salt to be stirred are introduced, and an outlet through which a silver halide fine particle emulsion generated after the stirring process is discharged, This is a stirring device provided with stirring means for controlling the stirring state of the liquid in the stirring tank by rotating the stirring blades in the stirring tank. As the stirring means, stirring and mixing are performed by two or more rotationally driven stirring blades in a stirring tank, and at least two stirring blades are arranged at opposing positions in the stirring tank and are opposite to each other. It is driven to rotate in the direction. The stirring blades have a structure that does not have a shaft penetrating the tank wall by an external magnet and a magnetic coupling arranged outside the tank wall to which each stirring blade is close, and each external magnet is arranged outside the tank. Each stirring blade is rotated by being rotationally driven by the set motor. On one of the stirring blade and the external magnet connected by the magnetic coupling, two surfaces 2 each having an N-pole surface and an S-pole surface arranged so as to be parallel to the rotation center axis and to overlap each other with the rotation center axis interposed therebetween. A pole-type magnet is used, and a left-right dual-portion magnet in which the N-pole surface and the S-pole surface are arranged symmetrically with respect to the rotation center axis on a plane perpendicular to the rotation center axis is used as the other. FIG. 1 shows an embodiment of a mixing container (stirring device) according to the present invention.

The stirring tank 18 is composed of a tank main body 19 whose central axis is oriented in the vertical direction, and a seal plate 20 serving as a tank wall for closing upper and lower open ends of the tank main body 19. Stirring blade 2
Numerals 1 and 22 are arranged at opposing upper and lower ends in the stirring tank 18 so as to be separated from each other, and are driven to rotate in opposite directions. Each of the stirring blades 21 and 22 forms a magnetic coupling C with an external magnet 26 disposed outside the tank wall to which the respective stirring blades 21 and 22 are adjacent. That is, each stirring blade 21, 2
2 are magnetically connected to the respective external magnets 26,
By rotating each external magnet 26 with independent motors 28 and 29, the rotation can be performed in opposite directions. Stirring tank 1
Reference numeral 8 denotes a silver salt aqueous solution, a halogen salt aqueous solution, and, if necessary, a colloid solution supplied to the liquid supply ports 11, 12, 1;
3 and an outlet 16 for discharging the silver halide fine grain emulsion after the stirring process. In the present invention, when the opposing stirring blades are driven in the mixing vessel, the number of rotations is 10
It is at least 00 rpm, preferably at least 3000 rpm. Further, the stirring blades rotating in opposite directions may have the same rotation speed or different rotation speeds.

Next, a method for producing the silver halide emulsion of the present invention will be described. The silver halide emulsion of the present invention can be produced in the process of nucleation → ripening → growth. In the present invention, it is preferable that the ionic strength in the dispersion medium solution be at least 0.2 or more and 2.0 or less, more preferably 0.3 or more and 1.0 or less, by adding ions other than the halogen salt at least during ripening or before growth. . Preferred ionic species are listed below, but are not limited thereto. Ions having a positive charge include H ⁺ , Na ⁺ , Mg
²⁺ , Ca ²⁺ , K ⁺ , Ba ²⁺ , Sr ²⁺ , Co ²⁺ , Ni ²⁺ ,
Examples thereof include Cu ²⁺ , Zn ²⁺ , and Al ³⁺ , and divalent or higher is more preferable. The ions having a negative ^charge, OH -, NO
₃ ⁻ , SO ₄ ²⁻ , ClO ₄ ⁻ , BF ₄ ⁻ , BF ₆ ⁻ ,
N ₃ ⁻ , CN ⁻ , C ₂ O ₄ ²⁻ , SCN ⁻ , C
O ₃ ^2-, COO ^-, and the like. As a method of supplying these ions, there is a method of supplying as an aqueous solution of an inorganic salt. Examples of the kind of the inorganic salt include, but are not limited to, the inorganic salts described in Chemical Handbook, Basic Edition II, pages 453 to 455 (Maruzen). The concentration of these inorganic salt aqueous solutions may be an appropriate concentration as long as the concentration is not more than the saturation concentration. As another supply method, an inorganic salt can be directly added in a powder state. At this time, the amount of addition is an amount that becomes the saturation concentration or less. In addition, the presence of the water-soluble polymer represented by the general formula (1) can improve monodispersity. When the water-soluble polymer represented by the general formula (1) is present during particle formation,
It may be present anywhere during grain formation, but it is desirable that it be present at least before growth, preferably before ripening, and more preferably before nucleation. The amount is 0.1 times or more by weight with respect to silver nitrate used for nucleation.
It can be used at times or less, preferably 0.1 times or more and 30 times or less.

Hereinafter, each process of nucleation, ripening, and growth will be described. 1. Nucleation The nucleation of tabular grains is generally performed by adding a silver salt aqueous solution and a halogen salt aqueous solution to a reaction vessel holding an aqueous solution of gelatin, or by a double jet method, or by adding a silver salt aqueous solution to a gelatin solution containing a halogen salt. A single jet method for addition is used. In addition, a method of adding an aqueous solution of a halogen salt to a gelatin solution containing a silver salt as needed can be used. Further, a silver salt aqueous solution and a halogen salt aqueous solution, and if necessary, a colloid solution are added and mixed to the mixing vessel of the present invention, and the mixture is immediately transferred to a reaction vessel to form nuclei of tabular grains. At this time, the protective colloid may be dissolved in the halogen salt aqueous solution. Also, as disclosed in US Pat. No. 5,104,786, nucleation can be carried out by passing an aqueous solution containing a halogen salt and a protective colloid solution through a pipe and adding an aqueous solution of a silver salt thereto. For the nucleation, it is preferable that the protective colloid is used as a dispersion medium and the dispersion medium is formed under the condition of pBr of 1 to 4. Gelatin is used as the protective colloid, but natural polymers other than gelatin are also used. Examples of the types of gelatin include alkali-treated gelatin, oxidized gelatin obtained by oxidizing methionine groups in gelatin molecules with hydrogen peroxide (methionine content of 40 μmol / g or less), phthalated gelatin, trimellitized gelatin, succinated gelatin, maleic Chemically modified gelatin such as gelatinized gelatin and esterified gelatin, and low molecular weight gelatin (molecular weight: 3000 to 40,000) are used. The natural polymer is Japanese Patent Publication No. 7-111550, Research Disclosure Magazine
Volume 176, No. 17643 (December 1978), section IX. The concentration of the dispersion medium is preferably 10% by weight or less, more preferably 1% by weight or less. The temperature during nucleation is 5
The temperature is preferably from 60 to 60 ° C, and more preferably from 5 to 48 ° C in the case of preparing fine tabular grains having an average particle size of 0.5 µm or less.
The pH of the dispersion medium is preferably 2 or more and 10 or less. The composition of the silver salt solution added, Br ^- for I ^- content is solid solubility limit of AgBrI generating less, preferably 1
0 mol% or less.

2. Aging 1. In the nucleation in (1), fine particles other than tabular grains (particularly, octahedral and single twin grains) are formed. Prior to the growth process described below, it is necessary to eliminate grains other than tabular grains to obtain nuclei having a shape to be tabular grains and good monodispersity. To make this possible, it is well known to carry out Ostwald ripening following nucleation. Immediately after the nucleation, pBr is adjusted, and the temperature is increased to ripen until the hexagonal tabular grain ratio becomes maximum. At this time, a gelatin solution may be additionally added. At that time, the concentration of gelatin in the dispersion medium solution is preferably 10% by weight or less. The additional gelatin used at this time is
The above-mentioned alkali-treated gelatin, chemically modified gelatin, oxidized gelatin, or a natural polymer is used. The aging temperature is 40 to 80 ° C, preferably 50 to 80 ° C, and the pBr is 1.2 to 3.0. At this time, a silver halide solvent may be added in order to quickly eliminate grains other than tabular grains. In this case, the concentration of the silver halide solvent is preferably 0.3 mol / liter or less,
It is more preferably 2 mol / liter or less. When used as an emulsion for direct reversal, a silver halide solvent such as a thioether compound used on a neutral or acidic side is preferable as a silver halide solvent than NH ₃ used on an alkaline side. The ripening is carried out in this way to obtain almost 100% tabular grains only. After ripening, if the silver halide solvent is unnecessary in the next growth process, the silver halide solvent is removed as follows. In the case of an alkaline silver halide solvent such as NH ₃ , an acid having a large solubility product with Ag ⁺ such as HNO ₃ is added to nullify the solvent. In the case of a thioether-based silver halide solvent, JP-A-6060
Add an oxidizing agent such as H ₂ O ₂ to invalidate as described in -136736.

3. The pBr during the crystal growth period following the ripening process is preferably maintained at 1.4 to 3.5. If the gelatin concentration in the dispersion medium solution before the growth process is low (1% by weight or less), gelatin may be additionally added. At that time, the gelatin concentration in the dispersion medium solution is preferably set to 1 to 10% by weight.
As the gelatin used at this time, the above-mentioned alkali-treated gelatin, chemically modified gelatin, oxidized gelatin, or a natural polymer is used. It is preferable that the addition rate of Ag ⁺ and halogen ions in the crystal growth period is 20 to 100%, preferably 30 to 100% of the critical crystal growth rate. In this case, the addition rates of silver ions and halogen ions are increased along with the crystal growth. In this case, Japanese Patent Publication Nos. 48-36890 and 52
As described in JP-A-16364, the addition rate of the aqueous solution of the silver salt and the halogen salt may be increased, and the concentration of the aqueous solution may be increased. Further, a silver salt aqueous solution and a halogen salt solution, and if necessary, a colloid solution are added to the mixing container of the present invention, and the mixture is stirred and mixed. Silver halide grains can be grown. At this time, a protective colloid (gelatin, synthetic polymer) may be dissolved in the aqueous halogen salt solution. Ag deposited on its nucleus during growth
The iodine content of X is preferably from 0 mol% to the solid solution limit concentration.

The silver halide in the present invention includes, for example, silver bromide, silver iodobromide, silver chlorobromide having a silver chloride content of 30 mol% or less, silver chloroiodobromide and the like. Other constitutions of the emulsion layer of the silver halide photographic light-sensitive material of the present invention are not particularly limited, and various additives can be used as needed. Chemical sensitizers, spectral sensitizers, antifoggants, metal ion dopants, silver halide solvents, stabilizers, dyes, color couplers, DIR couplers, binders, hardeners, coating aids, which can be added, Thickeners, emulsion sedimentants, plasticizers, dimensional stability improvers, antistatic agents, fluorescent brighteners, lubricants, surfactants, ultraviolet absorbers, scattering or absorbing materials, hardeners, anti-adhesion, photographic properties improvement Photographically advantageous fragments (development inhibitors or accelerators, bleaching accelerators, developers, silver halide solvents, toners, hardeners, antifoggants) Agents, competitive couplers, chemical or spectral sensitizers and desensitizers)
Releasing couplers, image dye stabilizers, self-suppressing developers,
And its use, also supersensitization in spectral sensitization, halogen acceptor effect and electron acceptor effect of spectral sensitizing dye, antifoggant, stabilizer, action of development accelerator or inhibitor,
In addition, a production apparatus, a reaction apparatus, a stirring apparatus, a coating method, a drying method, an exposure method (light source, an exposure atmosphere, an exposure method) used for producing the emulsion of the present invention, a photographic support, a microporous support, an undercoat layer, For the surface protective layer, matting agent, intermediate layer, antihalation layer, AgX emulsion layer structure, photographic processing agent and photographic processing method, see Research Disclosure, 1
Volume 76, December 1978 (item 17643),
184, August 1979 (item 1843)
1), 134 volumes, June 1975 issue (item 134
52), Product Licensing Index, Vol. 92, 107-110 (December, 1971), JP-A-58-113926-113928, JP-A-61-3134, JP-A-62-6251
No., JCIA Monthly Report, December 1984, pp. 18-27, JP-A-62-219982, TH James, The Theory of The Pho
tographic Process, Fourth Edission, Macmillan, New
York, 1977, VLZelikman et al. Making and
Coating Photographic Emulsion (The Focal Press,
1964) can be referred to. One or more silver halide emulsions of the present invention can be provided on a support together with other emulsions, if necessary. Further, the support can be provided not only on one side but also on both sides. Also,
It can also be overlaid as emulsions of different color sensitivity. The silver halide emulsion of the present invention can be used for black-and-white silver halide photographic light-sensitive materials (for example, X-ray light-sensitive materials, squirrel-type light-sensitive materials, negative films for black-and-white photography) and color photographic light-sensitive materials (for example, color negative films, color reversal films) , Color paper, etc.). Further, it can be used as a light-sensitive material for diffusion transfer (for example, a color diffusion transfer element, a silver salt diffusion transfer element), and a heat-developable light-sensitive material (black and white, color). Next, the present invention will be described in more detail by way of examples, but embodiments of the present invention are not limited thereto.

[0037]

【Example】

(Comparative Example 1) 1 liter of a dispersion medium solution containing 0.38 g of KBr and 0.5 g of low molecular weight gelatin (molecular weight: 15000) (pH = 5)
Is kept in a reaction vessel at 40 ° C., and while stirring it, a double jet method is used to prepare 0.29 mol / L of a silver nitrate solution.
mol / liter of a KBr solution was added in 20 cc portions for 40 seconds. After the addition, this dispersion medium solution was heated to 75 ° C. over 15 minutes. Alkali-treated gelatin 15 minutes after temperature rise
A dispersion medium solution (A) containing 35 g and 250 cc of water was newly added. At this time, the pH was adjusted to 6. After this, 1.2mol
734 cc / liter of silver nitrate solution were added at an accelerated flow rate. During this time, the KBr solution was added simultaneously so that the pBr was kept at 2.93. Comparative Example 2 Particle formation was performed in the same manner as in Comparative Example 1 except that a dispersion medium solution containing 35 g of oxidized gelatin and 250 cc of water was used instead of the dispersion medium solution (A). Was. Here, the oxidized gelatin is obtained by oxidizing alkali-processed gelatin with hydrogen peroxide to completely oxidize methionine in gelatin. Comparative Example 3 Particle formation was performed in the same manner as in Comparative Example 1 except that the dispersion medium containing 35 g of phthalated gelatin and 250 cc of water was used instead of the dispersion medium solution (A). . Here, phthalated gelatin is obtained by replacing 98% of amino groups in alkali-treated gelatin with phthalic anhydride. Comparative Example 4 Particle formation was performed in the same manner as in Comparative Example 1 except that a dispersion medium containing 35 g of trimellitated gelatin and 250 cc of water was used instead of the dispersion medium solution (A). Was. Here, the trimellitated gelatin means that the amino group in the alkali-treated gelatin is trimmed with trimellitic anhydride.
% Is replaced.

Example 1 Comparative Examples 1 to 4 were the same as Comparative Examples 1 to 4, except that the salt shown in (Table 1) was added at the same time as the addition of the dispersion medium solution (A) in the amount shown in (Table 1). Particle formation was performed in the same manner as in Nos. 1 to 3 to obtain particles A to K.

[0039]

[Table 1]

Each of the particles obtained in (Comparative Examples 1 to 4) and (Example 1) is a hexagonal AgBr tabular particle having a principal plane of {111} plane, and the size and size distribution are as shown in Table 2. ) And (Table 3). The grain thickness decreased with increasing average ionic strength during grain growth. By the method of increasing the ionic strength during grain growth according to the present invention, tabular grains having a small thickness and a narrow distribution of projected area diameter were obtained.

[0041]

[Table 2]

[0042]

[Table 3]

Comparative Example 5 A dispersion medium solution 1 containing 0.38 g of KBr and 0.5 g of low molecular weight gelatin (molecular weight: 15000)
Liter (pH = 5) was kept in a reaction vessel at 40 ° C., and while stirring it, 20 cc of each of 0.29 mol / l of silver nitrate solution and 0.29 mol / l of KBr solution were added by double jet method.
Added over 40 seconds. After the addition, this dispersion medium solution was heated to 75 ° C. over 15 minutes. 15 minutes after the temperature rise, a dispersion medium solution containing 35 g of alkali-treated gelatin and 250 cc of water (A)
Was newly added. At this time, the pH was adjusted to 6. Thereafter, a 1.2 mol / liter silver nitrate solution was added at an accelerated flow rate of 73
4 cc was added. During this time, a mixed solution of a KBr solution and a KI solution was added simultaneously so that the pBr was kept at 2.93. At this time, the KI solution in an amount of 3 mol% with respect to the amount of silver added was mixed with the KBr solution. Comparative Example 6 Particle formation was performed in the same manner as in Comparative Example 4 except that a dispersion medium solution containing 35 g of oxidized gelatin and 250 cc of water was used instead of the dispersion medium solution (A). Was.

(Example 2) In Comparative Example 5, the salt shown in (Table 1) was added simultaneously with the addition of the dispersion medium solution (A) (Table 1).
The particles were formed in the same manner as in Comparative Examples 5 and 6, except that the amounts shown in (1) and (2) were added to obtain particles from L to Q. The particles obtained in (Comparative Example 5), (Comparative Example 6), and (Example 2) are all hexagonal AgBrIs whose main plane is a {111} plane.
It was a tabular grain. Size and size distribution (Table 4)
And (Table 5). In the AgBrI tabular grain system, a tabular grain having a small thickness and a small distribution of projected area diameter was obtained by increasing the average ionic strength during grain growth.

[0045]

[Table 4]

[0046]

[Table 5]

(Example 3) In Example 1, immediately after the temperature was raised to 75 ° C, 50 cc of the synthetic polymer (P-1) of the present invention, which was a 4% aqueous solution, was added, and the pH was adjusted to 9.
The same steps as those for the C particles of Example 1 were performed. Each of the grains obtained in Example 3 was a hexagonal AgBr tabular grain having a principal plane of {111} plane, and the projected area diameter was 1.19 μm.
m, its coefficient of variation is 9.1%, and its thickness is 0.1%.
It was 11 μm. Further monodisperse tabular grains were obtained by using the synthetic polymer of the present invention.

Example 4 Dispersion medium solution 1 containing 0.38 g of KBr and 0.5 g of low molecular weight gelatin (molecular weight: 15000)
Liter (pH = 5) was kept in a reaction vessel at 40 ° C., and while stirring it, 20 cc of each of 0.29 mol / l of silver nitrate solution and 0.29 mol / l of KBr solution were added by double jet method.
Added over 40 seconds. After the addition, this dispersion medium solution was heated to 75 ° C. over 15 minutes. 15 minutes after the temperature rise, a dispersion medium solution containing 35 g of alkali-treated gelatin and 250 cc of water (A)
And (Table 1) No. 3 salt were added simultaneously. At this time, pH
Was adjusted to 6. Next, as shown in FIG. 1, a 0.6 mol / l silver nitrate solution and a 0.61 mol / l KBr solution containing 5% by weight of low molecular weight gelatin (average molecular weight: 15000) were placed in a mixer (volume: 2 cc), respectively. Was added at an accelerated flow rate. All of the grains obtained in Example 4 were hexagonal AgBr tabular grains having a principal plane of {111} faces, a projected area diameter of 1.23 μm, and a variation coefficient of 12.1%. The thickness was 0.08 μm. Using the mixer of the present invention, silver halide fine grains are previously produced in a mixing vessel, and this fine grain emulsion is added to a reaction vessel to grow tabular grains, whereby thinner, more monodisperse tabular grains are obtained. Was done.

(Example 5) After the particles were formed in exactly the same manner as in Example 1, the particles were cooled to 35 ° C, washed with water by flocculation, and dispersed at 50 ° C (emulsion Z). I got (Example 6) The emulsion Z obtained in Example 5 was subjected to chemical sensitization and spectral sensitization to give the fifth photosensitive material of Sample 6 (Sample No. 101) of Example 3 of JP-A-6-258788. Good performance was obtained by using the same layer and performing the same treatment as in the same example. (Example 7) Emulsion Z obtained in Example 5 was subjected to chemical sensitization and spectral sensitization to give photosensitive material X of Example 1 of JP-A-6-273866.
And used in the same manner as in Example 1 in combination with Screen B to obtain good performance. (Example 8) The emulsion Z obtained in Example 5 was subjected to chemical sensitization and spectral sensitization to give Example 1 of JP-A-2-854 (Sample No. 10).
It was used for the sixth layer of the light-sensitive material of 1) above, and was treated in the same manner as in the example to obtain good results.

(Example 9) The emulsion obtained in Example 4 was
A sensitizing dye was added at 40 ° C. in the same type and in the same amount as that of Emulsion D described in Japanese Patent Application No. 8-23714, and sodium thiosulfate, potassium chloroaurate and potassium thiocyanate were added. To give emulsion D. The obtained emulsion D was used in place of the emulsion D in the coating sample 106 of Example 1 of Japanese Patent Application No. 8-023714 to prepare multilayer color light-sensitive materials 201 and 202. The coating samples 201 and 202 were developed (first development time: 6 minutes) by the method described in Japanese Patent Application No. 8-023714, and as a result of comparing the curve on the high density side of the color cyan density, the sensitivity was high and the gradation was hard. That was confirmed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a schematic configuration of a stirring device according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Stirrer 11, 12, 13 Liquid supply port 16 Liquid discharge port 18 Stirring tank 19 Tank main body 20 Seal plate 21, 22 Stirring blade 26 External magnet 28, 29 Motor

Claims (7)

[Claims] 1. A step of forming silver halide grain nuclei containing twin grain nuclei in a dispersion medium solution, and b. Ripening the grain nuclei to preferentially leave tabular grain nuclei. ,
(C) a step of growing the tabular grain nuclei into tabular grains, wherein at least during the step (b) or in the dispersion medium solution immediately before the step (c), A method for producing a photosensitive silver halide photographic emulsion, characterized in that the ionic strength of the emulsion is adjusted to at least 0.2 or more with ions other than halogen ions. 2. The method for producing a silver halide photographic emulsion according to claim 1, wherein the dispersion medium contains at least one polymer having a repeating unit represented by the following general formula (1). Formula (1)-(RO) _n -wherein R represents an alkylene group having 2 to 10 carbon atoms.
n represents the average number of repeating units, and represents 4 or more and 200 or less. 3. A polymer having a repeating unit represented by the general formula (1) is a vinyl polymer containing at least one kind of a monomer represented by the following general formula (2) or a vinyl polymer represented by the following general formula (3): 3. The method for producing a silver halide photographic emulsion according to claim 2, wherein the emulsion is at least one polymer selected from polyurethane. General formula (2) General formula (3) In the formula, R represents an alkylene group having 2 to 10 carbon atoms. n represents the average value of the repeating unit and represents 4 or more and 200 or less. R ¹ represents a hydrogen atom or a lower alkyl group;
² represents a monovalent substituent. L represents a divalent linking group. R
³ and R ⁴ are an alkylene group having 1 to 20 carbon atoms, a phenylene group having 6 to 20 carbon atoms, or a C 7 to 2 carbon atom.
Represents an aralkylene group of 0. x, y, z represent the weight percentage of each component, x is 1 to 70, y is 1 to 70,
z represents 20 to 70. Here, x + y + z = 10
0. 4. A polymer having a repeating unit represented by the general formula (1) has a polyalkylene oxide block polymer component represented by the following general formulas (4) and (5). A method for producing a silver halide photographic emulsion according to claim 2. General formula (4) General formula (5) In the formula, R ⁵ is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms,
Represents an aryl group having 6 to 10 carbon atoms, and n is 1 to 10
Represents an integer. Here, when n = 1, R ⁵ does not become a hydrogen atom. R ⁶ represents a hydrogen atom or a lower alkyl group having 4 or less carbon atoms and substituted by a hydrophilic group. x,
y represents the number of repetitions of each unit (number average degree of polymerization). 5. A mixing vessel is provided outside the reaction vessel for performing the nucleation step and / or the growing step, and an aqueous solution of a water-soluble silver salt and an aqueous solution of a water-soluble halogen salt are supplied to the mixing vessel and mixed. The silver halide grains are formed, the fine particles are immediately supplied to the reaction vessel, and nucleation and / or growth of the silver halide grains is performed in the reaction vessel. 5. The method for producing a silver halide photographic emulsion according to item 4. 6. A closed stirring tank provided with a predetermined number of supply ports through which the mixing vessel flows the additive liquid to be stirred and a discharge port through which a silver halide fine grain emulsion formed after the stirring process is discharged. And stirring means for controlling the stirring state of the liquid in the stirring tank by rotating at least one stirring blade having no rotation axis penetrating the stirring tank wall in the stirring tank. The method for producing a silver halide emulsion according to claim 5, wherein 7. A closed stirring tank provided with a predetermined number of supply ports through which the mixing vessel flows the additive liquid to be stirred and a discharge port through which silver halide fine grain emulsion produced after completion of the stirring process is discharged. And stirring means for controlling the stirring state of the liquid in the stirring tank by rotating the stirring blades in the stirring tank, and two or more rotation-driven stirrings in the stirring tank. 6. The silver halide emulsion according to claim 5, wherein the stirring is performed by the blades, and at least two stirring blades are separately arranged at opposing positions in the stirring tank and are driven to rotate in directions opposite to each other. Manufacturing method.