JPH07234470A - Silver halide emulsion - Google Patents

Abstract

PURPOSE:To obtain a silver halide emulsion good in the reproducibility of manufacture and superior in uniformity among the grains, sensitivity, graininess, and spectral sensitizability by forming specified flat grains in a specified amount of the silver halide grains. CONSTITUTION:The flat silver halide grains having principal faces {100} and an aspect ratio (diameter/thickness) of >=1.5 are contained in >=30% of the projection areas of the total silver halide grains. The difference between the contents of Cl<-> or Br<-> acrossing a gap in the central part of each grains is 10-100mol%, and that in the content of I<-> is 5-100mol%, and one or more halogen composition gap faces are formed by adding a solution of halogen salt different by >=10mol% in Cl<-> or Br<->, and by >=5mol% in I<-> from the halogen ion composition of a host silver halide nucleus to this nucleus, thus permitting uniform defects to be formed among each grain and to obtain silver halide emulsion to be improved in the reproducibility of the manufacture and enhanced in spectral sensitizability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silver halide (hereinafter referred to as "AgX") emulsion useful in the field of photography, and particularly to an AgX emulsion containing tabular grains having {100} faces as major faces. Regarding

[0002]

2. Description of the Related Art When tabular AgX emulsion grains are used in a photographic light-sensitive material, color sensitization, sharpness, light scattering characteristics, covering power, development progress and graininess are improved as compared with non-tabular AgX grains. It For this reason, tabular grains having twin planes parallel to each other and having a {111} plane as a main plane have been frequently used. However, when a large amount of the sensitizing dye is adsorbed on the AgX grains, the grains having {100} faces generally have better color sensitizing properties. Therefore, the main plane is {10
Development of tabular grains having a 0} plane is desired. The {100} tabular grains whose main plane shape is a right-angled parallelogram are described in JP-A-51-88017, JP-B-64-8323 and EP-A-0,534,395A1. However, none of these grains has a discontinuous halogen composition gap surface in the center, and is of a uniform halogen composition type or a gentle halogen composition change type. in this case,
It is difficult to properly prepare the tabular grains, the production variation is large, and the AgX emulsion has a wide size distribution. Also,
The particles were not satisfactory in terms of sensitivity, graininess and image quality. The tabular grains having a halogen composition gap surface in the center are described in Japanese Patent Application No. 5-96250. However, the inter-particle uniformity of defect formation, manufacturing reproducibility, sensitivity, and graininess were not sufficient. Further, the spectral sensitization sensitivity of the grains was not sufficient.

[0003]

The object of the present invention is to provide good production reproducibility, more excellent interparticle uniformity, sensitivity, graininess,
An object is to provide an AgX emulsion having more excellent spectral sensitization characteristics.

[0004]

The objects of the present invention have been achieved by the following items. (1) In a silver halide emulsion having at least a dispersion medium and silver halide grains, 30% or more of the total projected area of the silver halide grains has a {100} plane as a main plane and an aspect ratio (diameter / thickness). ) Is a tabular grain having a grain size of 1.5 or more, and the central portion of the grain has one or more halogen composition gap faces having the following (a) and (b). (a) The gap has a Cl ^- content or a Br ^- content of 10 to 10
The difference is 100 mol%, or the difference in I ⁻ content is 5 to 100 mol%. (b) The gap is in the host silver halide nucleus, and the halogen ion composition of the nucleus and the Cl ⁻ content or the Br ⁻ content is 10.
It is a gap surface formed substantially by a halogen conversion reaction caused by adding a halogen salt solution different in mol% or more, or in I ^- content by 5 mol% or more.

(2) In a silver halide emulsion having at least a dispersion medium and silver halide grains, 30% or more of the total projected area of the silver halide grains has a main plane of {100}.
Surface is a tabular grain having an aspect ratio (diameter / thickness) of 1.5 or more, and the tabular grain has the following (a) to
(B) A silver halide emulsion having a core part and a shell part. (a) of the core Cl ^- in content: 60 mol% or more, the shell portions Br ^- and the content: 30 mol% or more and, (Cl shell portion ^- content / the core portion Cl ^- content: ) Is 0.8 or less. (b) The shell portion is laminated substantially uniformly on at least the main plane of the core portion, and has a thickness of 3 atomic layers or more.

Other preferred embodiments of the present invention are as follows: (3) The silver halide emulsion according to (1) above, wherein the halogen composition of the halogen salt solution satisfies the following relationship. The solubility of silver halide having the halogen composition is smaller than that of silver halide having the halogen composition of the host nucleus under the same conditions. (4) The grain has at least one halogen composition gap surface in the center thereof, and the gap has a Cl ⁻ content or a Br ⁻ content of 1 or less.
The silver halide emulsion according to (2) above, which has a difference of 0 to 100 mol% or a difference of 5 to 100 mol% in I ^- content.

Next, the present invention will be described in more detail. In the above (1) and (2), the projected area means the size of the grains when the AgX emulsion grains do not overlap each other and the tabular grains are arranged on the substrate in a state where the main plane is parallel to the substrate surface. Refers to the projected area. The AgX emulsion of the present invention is an AgX emulsion having at least a dispersion medium and AgX grains.
30% or more of the total projected area of the grains, preferably 60 to
100%, more preferably 80 to 100%, the main plane is the {100} plane and the aspect ratio (diameter / thickness) is 1.5.
The number of tabular grains is not less than 2, preferably not less than 2, more preferably 3 to 25, still more preferably 3 to 10.

The diameter of the tabular grain means the diameter of a circle having an area equal to the projected area of the grain when the grain is observed with an electron microscope. The thickness refers to the distance between the main planes of tabular grains. The thickness is preferably 0.5 μm or less, more preferably 0.03 to 0.3 μm, and 0.05 to
0.2 μm is more preferable. The tabular grains have a circle-equivalent projected particle size of preferably 10 μm or less, more preferably 0.2 to 5 μm. The halogen composition of the tabular grains is not particularly limited, and any composition is possible, but the I ⁻ content is preferably 20 mol% or less, more preferably 0 to 10 mol%. The diameter distribution of the particles is preferably monodisperse, and the coefficient of variation (standard deviation / average diameter) of the distribution is preferably 0 to 0.4, more preferably 0 to 0.3, still more preferably 0 to 0.2. preferable.

The main plane of the tabular grains is a right-angled parallelogram, and the ratio of adjacent sides [(length of long side / length of short side) of one grain] is 1 to 10, preferably. 1 to 5, more preferably 1 to 2, a shape in which one or more of four corners of a right-angled parallelogram are non-equivalently omitted (details are described in Japanese Patent Application Nos. 4-145031 and 5-264059). No.) can be referred to), an aspect in which at least two opposite sides of the four sides constituting the main plane are curved curves outwardly convex, four angles of a right-angled parallelogram As shown in FIG. 1, one or more of the two are missing in a rectangular parallelepiped shape, and the four corners are equivalently missing [(maximum missing area / minimum missing area of the main plane within one particle. ) <2 aspect can be mentioned. , And more preferably, and tabular grains having a {111} plane in the lacking part are more preferable. {11 for all surfaces of tabular grains
The area ratio of the 1} plane is preferably 0 to 40%, and 0.5 to 2
0% is more preferable.

Next, the aspect (1) will be described. The tabular grains have the following characteristics (a) and (b). (A)
The tabular grain has a halogen composition gap surface in the center thereof, and the gap has a Cl ⁻ content or a Br ⁻ content of 10 to 10.
The difference is 100 mol%, preferably 30 to 100 mol%, more preferably 50 to 100 mol%. Or I ^-
The content is 5 to 100 mol% difference, preferably 10 to 100 mol% difference, and more preferably 30 to 100 mol% difference.
(B) The gap surface is in the host AgX nucleus in terms of halogen ion composition and Cl ⁻ content or Br ⁻ content of the nucleus of 10 mol% or more, preferably 30 to 100 mol%, more preferably 50 to 100 mol%. , Or I ^- content of 5 mol% or more, preferably 10 to 100 mol%, more preferably 3
It is a gap surface formed substantially by a halogen conversion reaction caused by adding halogen salt solutions that differ by 0 to 100 mol%. Here, "substantially" means that the molar amount a ₁ of the Ag ⁺ solution added at the same time as the halogen salt solution and the molar amount a ₂ of the halogen salt solution added are a ₁ / a ₂ <0.9. , Preferably a ₁ / a ₂ = 0
To 0.6, more preferably 0 to 0.3, still more preferably 0 to 0.1.

The halogen composition of the halogen salt solution more preferably satisfies the following relationship. A of the halogen composition
Solubility b _{1 of} gX and AgX of halogen composition of the host nucleus
(B ₁ / b ₂ ) is preferably less than 1, more preferably 0.8 or less, still more preferably 10 ^{−5 to} 0.3 under the same solubility b ₂ of. The halogen conversion reaction can be carried out once or more, preferably 1 to 4 times, more preferably 1 to 2 times. A specific example is as follows. AgNO ₃ solution and halogen salt solution (hereinafter "X
^- "Salt solution") is added to the dispersion medium solution with stirring to form AgX ₁ nuclei. Next, X ^- salt solution is added to carry out a halogen conversion reaction, and (AgX ₁ | A
gX ₂ ) form nuclei. This can be the end of nucleation, or AgNO ₃ or AgNO ₃ and X ^- salt solution can be further added to form (AgX ₁ | AgX ₂ | AgX ₃ ) nuclei. Alternatively, X ^- salt solution is further added to carry out a halogen conversion reaction, and (AgX ₁ | A
The gX ₂ | AgX ₃ | AgX ₄ ) nuclei can be formed or can be repeated. The AgX ₁
And AgX ₃ may have the same halogen composition or different halogen compositions. The most preferable halogen composition can be selected and used.

The molar amount of the halogen salt solution added to carry out the conversion reaction is Ag of the host nucleus.
The molar amount of X ₁ is preferably 0.01 times or more, more preferably 0.1 times or more. The (AgX ₁ | AgX ₂ | Ag
In the case of X ₃ ) nuclei, the thickness of the gap plane AgX ₂ phase is 0.1.
The atomic layer or more is preferable, and the atomic layer or more is more preferable.
By carrying out the conversion reaction, crystal defects causing the formation of the tabular grains are formed. The Ag
The size of X ₁ is preferably 0.2 μm or less, and is 0.02 to
0.1 μm is more preferable.

Next, the method for preparing the particles will be described in detail. First, the nucleation process will be described in order. (1) Nucleation Ag ⁺ and X ⁻ are reacted in a dispersion medium solution containing at least a dispersion medium and water to first form a host silver halide nucleus AgX ₁ nucleus. Next, an X ^- salt solution is added to cause a halogen conversion reaction on the surface of the AgX ₁ nucleus to substantially form a crystal defect that causes tabular grain formation. In order to form the defects, the reaction condition must be a {100} plane forming atmosphere. For details, refer to Japanese Patent Application No. 5-962.
The description of No. 50 can be referred to. Therefore {1
00} surface formation promoter can coexist. The coexisting amount is preferably 5% or more of the saturated adsorption amount to the nucleus, and 10
~ 300% is more preferable. The crystal habit controlling agent refers to a compound which, by the coexistence, lowers the equilibrium crystal habit silver potential of AgX particles under the nucleation condition by 10 mV or more, preferably 30 to 200 mV.

Specifically, the area of the [{100} plane / {1
It means that particles having the same [11} plane area] ratio can be obtained under the lower silver potential by allowing the compound to coexist. As the crystal habit controlling agent, European Patent 0,534,395
In addition to the compounds described in A1, gelatin with a high methionine content (preferably 10 μmol / g or more, more preferably 3
0 to 200 μmol / g), a water-soluble dispersion medium known for AgX emulsions (research disclosure for general,
Volume 307, Item 307105, November 1989 can be referred to, especially Japanese Patent Publication No. 52-163.
No. 65, JP-A-59-8604, Journal of Imaging
Science, Volume 31, 148 to 156 (1987) are more preferable).

The nucleation temperature is preferably 5 to 70 ° C., 1
0-50 degreeC is more preferable. The smaller the size of the nucleus, the easier the next ripening proceeds. From that point, it is preferable to perform nucleation at a low temperature. On the other hand, in order to cause the halogen conversion reaction to form the defects, energy is required and high temperature is required. In order to satisfy both of them, the formation of AgX ₁ nuclei and the addition of the X ^- salt solution are carried out at a low temperature, then preferably 2 ° C or higher, more preferably 5 to 3
It is sufficient to raise the temperature by 0 ° C.

After the (AgX ₁ | AgX ₂ ) nuclei are formed in this way, the aging process can be started next, but Ag ⁺ salt solution, or Ag ⁺ salt solution and X ^- salt solution is added. ,
More preferably, (AgX ₁ | AgX ₂ | AgX ₃ ) nuclei are formed. Here, it is preferable that X ₁ and X ₃ have substantially the same halogen composition. It is the next aging process,
This is because it is possible to prevent the accumulation of AgX ₂ deposits on the tabular grains and to generate more defects in the tabular grains. AgX
_{When three} phases are present, X ₂ is diluted with X ₃ during aging, so that the defect formation is prevented. Here, “substantially the same” means that the difference in Cl ⁻ , Br ⁻ and I ⁻ content is preferably 30.
It is within mol%, more preferably 0 to 10 mol%. The addition amount of AgX ₃ is preferably 1 time or more, and more preferably 5 to 300 times the amount of AgX ₂ .

(Number of defects / particles) = If C ₁ is too large,
The finally obtained particles are thick particles having a low aspect ratio, which are growth-promoted in the x-, y-, and z-axis directions. Where x, y
The axes are parallel and orthogonal to the major plane and the z-axis is perpendicular to the major plane. Therefore, the defect formation amount may be controlled so that the generation frequency of thick grains is low and the generation frequency of tabular grains is high. The larger the difference in halogen composition gap between AgX ₁ and AgX ₂ , the greater the defect formation amount becomes (AgX ₂ /
It increases as the molar ratio of AgX ₁ ) increases. The dispersion medium concentration is usually 0.1 to 10% by weight, and the pH is 1 to 12, preferably 2 to 7. The defect formation is I ^- not the content: difference, Br ^- or Cl ^- it is more preferably formed by content: difference. The potential can be determined by a so-called potentiometric method, which is a potential difference between a silver ion selective electrode (for example, a silver electrode) and a saturated calomel electrode.

(2) Aging It is difficult to prepare only tabular grain nuclei during nucleation. Therefore, grains other than tabular grains are eliminated by Ostwald ripening in the next ripening process. The temperature is preferably higher than the nucleation temperature by 10 ° C. or higher, usually 50 to 9
0 ° C is used. Non-tabular nuclei disappear by aging and deposit on tabular grains. Almost all of the non-tabular nuclei (preferably 70% or more in number, preferably 95 to 100%) can be eliminated by the aging, but the following method can also be preferably used. In order to prevent AgX _{2 from} being deposited on the tabular grains during aging and causing more defects in the tabular grains, it is preferable to add fine particles having the composition of AgX ₃ after the nucleation. And / or Ag
⁺ Salt solution and X ₃ ^- is preferably ripening while adding salt solution. It is preferable that the AgX ₂ is diluted with the AgX ₃ and added in an amount such that no new defects are substantially generated in the tabular grains.

Here, “substantially” means preferably 50% or less, more preferably 0 to 20%, of the already existing defect amount,
0 to 10% is more preferable. In addition, these methods can be used in combination. For example, first, 10% or more, preferably 20 to 95% of the non-platen nucleus is aged to be eliminated, and then the remaining non-platen nucleus is added with a low supersaturation degree of Ag ⁺ salt solution and X ^- salt solution. Method to eliminate or Ag
⁺ Tabular grains are preferentially grown in the edge direction while adding a low supersaturation degree of salt solution and X ^- salt solution to increase the size difference from non-tabular grains and then aged to eliminate non-tabular grains. You can also Here, the low supersaturation degree means that (growth rate of grains having no defect / growth rate of tabular grains in the edge direction) = d ₁ is preferably 0.5 or less, more preferably 0.1 or less, and further preferably Indicates a state of 0 or less.

(3) Growth After the aging, the particles can be further grown to a desired size, if necessary. In this case, 1) an ion addition method of growing by adding Ag ⁺ salt solution and X ^- salt solution, 2)
Examples thereof include a method of forming AgX fine particles in advance and adding the fine particles to grow the particles, 3) a combination method of both. Regarding the halogen composition structure in the tabular grains, the description in Japanese Patent Application No. 5-96250 can be referred to.

Next, the aspect (2) will be described. The tabular grains have a core part and a shell part having the characteristics described in (a1) and (b1) below. (A1): (1) in FIG.
In (2), Cl core portion AgX ₅ ^- content: 60 mol% or more, preferably from 70 to 99.99 mol%, more preferably 90～99,95 mole%, the shell section Ag
The Br ⁻ content of X ₆ is 30 mol% or more, preferably 50 to
It is 100 mol%, more preferably 70 to 100 mol%. Furthermore (Cl shell portion ^- Cl of content: / core section ^- content) is 0.8 or less, preferably 0 to 0.5, more preferably 0 to 0.2. (B1): the shell portion is laminated substantially uniformly on at least the main plane of the core portion,
The thickness is 3 atomic layers or more, preferably 5 to 700 atomic layers, and more preferably 5 to 300 atomic layers. Here, “substantially uniform” means that the variation coefficient of variation in the laminated thickness within one particle is 0.4 or less, preferably 0 to 0.3, and more preferably 0 to 0.1. More preferably, an embodiment in which the core portion is laminated substantially uniformly on all surfaces can be mentioned. More preferably, it is possible to cite an embodiment in which the laminated thickness on the main plane is substantially uniform even among particles. More preferably, an embodiment in which the laminated thickness on all surfaces of the core part is substantially uniform even among particles can be mentioned. The above-mentioned "substantially uniform" complies with the above definition.

Furthermore the Br of the shell portion ^- variation coefficient between the particles of the content: (the Br ^- standard deviation of the particle distribution among content: / Mean Br ^- content:) is preferably 0.4 or less, more preferably Is preferably 0 to 0.3, more preferably 0 to 0.1. In addition, in FIGS. 2A and 2B, the shell layer has a multi-layer structure of two or more layers, and the Br ⁻ content gradually decreases from the surface to the inside of the particle. You can The Br ⁻ content gap of the joint surface between the core portion and the shell portion is preferably 70 mol% or less, more preferably 5 to 35 mol%. This is because if the content difference is too large, the core portion may dissolve during the lamination, and the shape of the tabular grains may collapse. Furthermore, the shell portion may contain I ^{− in an amount} of 20 mol% or less, preferably 0.1 to 10 mol%.

It is more preferable that the I ^- content in the shell portion decreases in order from the surface to the inside, and it is more preferable that the I ^- content is localized within 10 atomic layers, preferably within 5 atomic layers from the surface. It is preferable that I ⁻ is substantially uniformly distributed at least on the main planes of the particles, and it is preferable that I ⁻ is also substantially uniform among the particles. Furthermore, the shell part may contain SCN ^{− in an amount} of preferably 0.1 mol% or more, and more preferably 1 to 50 mol%. It is preferable that SCN ⁻ is localized within 10 atomic layers, more preferably within 3 atomic layers from the surface. SC
It is preferable that N ⁻ is substantially uniformly distributed at least on the main plane, and it is preferable that N ⁻ is also substantially uniform among particles. The term “substantially uniform” means preferably 0.4 or less, more preferably 0 to 0.3, and further preferably 0 to 0.1.

Such a particle structure has the following advantages.
Since most of the AgX particles (preferably 60% or more, more preferably 75 to 98%) are AgCl, development progresses quickly, and the processing amount of the photosensitive material per unit developing solution amount is large. Therefore, the amount of waste developer can be reduced. On the other hand, A
When the surface of the gX particle is AgCl, the polarizability thereof is small, so that the adsorption of the sensitizing dye mainly adsorbed by the Van der Waalska is weak, but in the case of the particle, Br ^{− of} the particle surface is ^−. Adsorption of the sensitizing dye is enhanced due to the increased content. Further, if necessary, the surface I ^- content is increased to enhance the adsorption power of the sensitizing dye. Br
^Since- and I ^- are localized on the surface of the particle and in the vicinity of the surface, the highest purpose is obtained with a small content. Further, Br ⁻ and I ⁻ on the grain surface lower the solubility of AgX grains and also have a function of preventing an increase in fog during chemical sensitization and during storage of emulsions and light-sensitive materials. That is, the particle surface characteristics are the same as those of conventional AgB.
It is close to the rI particle system.

When the development processing speed is increased, if the initial development speed is increased, the differentiation between the latent image and the fog nucleus is reduced, resulting in low feeling,
Higher fog. On the other hand, even if the late development speed is increased, the effect is small. Since the particles accelerate the late development rate more than the initial development, the defects thereof are less. Most of the particle surface (preferably 60% or more, more preferably 8% or more).
0 to 100%, more preferably 95 to 100%) is {1
Since it is the {00} plane, the polarizability of the grain surface is larger than that of the {111} plane, so that the sensitizing dye adsorption ability is enhanced. It has a surface A, rather than a {111} plane with only X ^- ions.
This is based on the fact that the Heitler-London dispersive force and the induced dipole moment are larger in the {100} plane composed of g ⁺ and X ⁻ ions. Therefore, the I ⁻ content and Br ⁻ content of the grain surface can be further reduced as compared with the conventional {111} plane system.

Regarding the fact that the {100} plane has higher spectral sensitization efficiency than the {111} plane, Japanese Patent Application No. 5-264059.
You can refer to the description of the issue. The comparison of the Van der Waals interaction forces of the {100} plane and the {111} plane can be simply compared by the magnitude of the dielectric constant in the direction parallel to the plane. The dielectric constant of the {100} plane and the dielectric constant of the {111} plane are obtained by forming a capacitor using AgX single crystal, and measuring the dielectric constant in the direction parallel to the {100} plane and the dielectric constant in the direction parallel to the {111} plane. It can be determined by measuring the dielectric constant. At this time, the ion conductive component of the AgX single crystal can be removed and measured by increasing the measurement frequency. In addition, a clean AgX single crystal {1
It is also possible to obtain the reflectance n of the transparent light with respect to the {00} plane and the {111} plane, and obtain the respective surface high-frequency permittivities from the relationship of n ² = permittivity, and make a comparison.

[0027] of the surface layer I ^- the Ag ⁺ salt solution and X ^- can either be mixed by the simultaneous mixing method of adding liquid salt, X after grain growth ^- by adding a salt solution but also it is incorporated it can. However, the latter is preferred because I ⁻ can be localized on the surface, and the desired effect can be obtained with a smaller addition amount. In order to form the grains having the structure shown in FIG. 2, it is necessary to grow the AgX ₆ layer almost uniformly on all surfaces of the tabular grains. For that, A
g ⁺ salt solution and X ^- High supersaturation addition of salt solution, and / or X
^- it may be high supersaturation addition of salt solution. The most preferable addition conditions may be determined by adding them at various addition rates, examining the halogen composition structure of the produced particles.

As a grain analyzing method, a section of the tabular grain is scan-excited with an electron beam to detect emission of halogen atoms (for example, characteristic X-ray) in each section of the section (scanning electron microscope method), Secondary ion mass spectroscopy
The law can be mentioned, Journal of the Photographic Society of Japan, vol. 53, 1
25-131 (1990) can be referred to. When they are added at a high flow rate, the formation of the AgX ₆ phase becomes non-uniform among particles. In addition, the I ⁻ distribution on the particle surface becomes non-uniform. In this case, the addition is carried out through a porous body existing in the reaction solution, preferably a hollow tubular rubber elastic body porous membrane (for details, see JP-A-3-21339, 4-193336, 4-229852). Issue, Japanese Patent Application No. 4
No. 240283), JP-A-4-28.
It is preferable to use one or more, preferably two or more of the uniform mixing methods described in Japanese Patent Application No. 3741 and Japanese Patent Application No. 4-302605.

The particles of the above structure in FIG. 2 have a Cl ⁻ concentration of 1
0 ^-3 mol / liter or more, preferably 10 ^-2.5 to 10 ^-1 mo
It is preferably formed under the condition of 1 / l. Also in the case of grains having other halogen composition structures, it is preferable to form them at the Cl ⁻ concentration. This is because it is preferable that the tabular grain formation is carried out under the cubic grain formation condition, and the Cl ^- concentration condition corresponds to the cubic grain formation condition. The excess Cl ⁻ can be regarded as a kind of crystal habit controlling agent. When the tabular grains having an AgCl content of 99.5% or more are cooled to −100 ° C. or less and the transmission electron micrograph image of the grains is observed, dislocation lines as shown in FIG. 3 may be observed. Many.

[0030] Other, wherein (1) to sulfur in between flat of the gap of the particles adjacent phase (4), selenium, ^{tellurium, SCN -, SeCN -, TeCN} -, CN -, Ag
The content difference of at least one kind of metal ion other than ⁺ and a complex of the metal ion (as the ligand, X ^- ligand, CN ^- ligand, isocyano, nitrosyl, thionitrosyl, amine and hydroxyl) can be mentioned. Preferably 0.1 to 100 mol% difference, more preferably 1 to 100 mol% difference, further preferably 10 to 100 mol% difference.
An embodiment in which there is a mol% difference can be mentioned. As representative examples of metal ions other than Ag ⁺ , Group 8 metal ions of the periodic table, Cu, Zn, Cd, In, Sn, Au, Hg, P
Examples thereof include metal ions of b, Cr and Mn.

In addition, there can be mentioned a mode in which the entire AgX particles are doped with these impurity ions, a mode in which the AgX particles are doped in a specific place, and a mode in which the impurities are localized within 0.1 μm from the particle surface and doped. . In this case, the dope concentration is preferably 10 ^-8 to 10 ^-1 mol / mol AgX, more preferably 10 ^-7 to 10 ^-2 mol / mol AgX.
For specific examples of these impurity ions and details of the method of doping the AgX phase, see Research Disclosure, 3
Volume 07, Item 307105, November, 1989,
US Pat. Nos. 5,166,045, 4,933,272 and 5,
No. 164292, No. 5132203, No. 426992
No. 7, No. 4847191, No. 4933272, No. 4
No. 981781, No. 5024931, Japanese Patent Laid-Open No. 4-30
No. 5644, No. 4-321024, No. 1-18364
The descriptions of No. 7, No. 2-20853, No. 1-285941, and No. 3-118536 can be referred to.

Other details regarding the method and structure for producing the tabular grains of the above-mentioned modes (1) to (4) are described in JP-A-5-31.
No. 3273, No. 5-281640, Japanese Patent Application No. 5-962
No. 50, No. 5-248218, No. 5-264059.
No. 5, No. 5-117624, No. 4-214109, and the description of the homogeneous mixing method can be referred to.
During the growth of the particles and the AgX ₆ layer, it is preferably 0.2 μm or less prepared in advance, and more preferably 0.02 μm or less.
A method of growing by adding AgX fine particles having a diameter of 0.1 μm can be preferably used. Compared with the ion addition method, the selective growth property of tabular grains in the edge direction is higher, and the Cl ⁻ concentration and pH range are wider (Cl ⁻ concentration is 10 ⁻¹ to 10 ⁻³ mol / liter region). Preferably p
H is preferably 3 to 8 and the temperature is more preferably 30 to 90 ° C.), and is more preferable in order to give tabular grains having a high aspect ratio.

At the time of grain growth, the {100} plane formation promoter can be made to coexist according to the above rules. Alternatively, a {111} plane formation accelerator can coexist. The crystal habit controlling agent causes the equilibrium crystal habit potential of the AgX particles produced by the coexistence to be 10 mV or more, preferably 30 to 200.
Refers to compounds that raise mV. In this case, the particles of the above aspect can be obtained more easily. Regarding specific compound examples, US Pat. Nos. 4,399,215 and 44143.
No. 06, No. 4400463, No. 4713323, No. 4804621, No. 4783398, No. 49524.
91, 4983508, Journal of Imaging Sci
ence, 33, 13 (1989), 34, 44
(1990), Journal of Photographic Science, 3
Reference can be made to the description in Volume 6, 182 (1988).

Since most of the grains are {100} planes,
The adsorption group of gelatin (eg, methionine group) is strongly adsorbed to Ag ⁺ on the surface of the grain. Therefore, the adsorption of the spectral sensitizing dye, the antifoggant and other photographic additives may be excluded. In this case, the dispersion medium gelatin having the optimum methionine content can be selected. Specifically, the photosensitive material AgX
The average methionine content of gelatin in the emulsion layer is preferably 0 to 50 μmol / g, and more preferably 3 to 30 μmol / g. The chemical sensitizer can be added to the AgX emulsion at 10 ^-2 to 10 ^-8 mol / mol AgX, and the sensitizing dye can be added at a saturated adsorption amount of preferably 5 to 100% for sensitization. As the spectral sensitizing dye for the tabular grains, the sensitizing dye described in U.S. Pat. No. 4,987,064 can be preferably used, especially when the Cl ^- concentration on the grain surface is 10 to 100 mol%.

As the grain forming method for forming the halogen composition gap in the nuclei, in addition to the above-described embodiment, i) the nucleation → ripening in the {100} plane forming region and growing in the {111} plane forming region, ii ) In the {111} plane forming region, the nucleation → aging,
Examples thereof include a method of growing in the {111} plane forming region, iii) a method of growing in the {100} plane forming region by nucleating and aging the {111} plane forming region. ii) gives {111} twin grains (mainly single twin and parallel double twin grains),
iii) gives {100} twinned grains. The condition iii) usually forms edge dislocations, but since it does not give the tabular grains, it seems that mere edge dislocations cannot be the cause of the tabular grain formation. The growth mode of the particles in the edge direction is 0.5 to 3 mol% difference A with different iodine contents.
A method of additionally growing a gX layer and (i) observing its low temperature luminescence [eg, Journal of Imaging Science, Vol. 31,
15-26 (1987)], or (ii) a method of observing the iodine content gap face with a direct method low-temperature transmission electron micrograph image of the particles. it can. For example, the aspects of FIGS. 4A to 4C are observed.

The obtained particles may be used as host particles, and epitaxial particles may be formed on the edges and / or corners of the particles before use. Further, particles having dislocation lines inside may be formed using the particles as a core. In addition, by using the particles as a substrate and stacking an AgX layer having a halogen composition different from that of the substrate, particles having various known particle structures can be prepared. Regarding these, it is possible to refer to the description of the literature described later. Also,
Chemical sensitization nuclei are usually imparted to the obtained emulsion grains.

In this case, the number and location of the chemically sensitized nuclei are generated.
It is preferred that cm ² be controlled. Regarding this, JP-A-2-838, 2-146033 and 1-2.
No. 01651, No. 3-121445, JP-A-64-7
No. 4540, Japanese Patent Application Nos. 3-73266 and 3-1407.
No. 12 and No. 3-115872 can be referred to.

A shallow inner latent emulsion may be formed by using the tabular grains as a core. It is also possible to form core / shell type particles. Regarding this, JP-A-59-
133542, 63-151618, U.S. Pat. Nos. 3,206,313, 3,317,322, 3,761,276, 4,269,927, 3,267,778. Can be referred to. The AgX emulsion grains produced by the method of the present invention can also be used as a blend with one or more other AgX emulsions.
The blending ratio can be appropriately selected and used in the range of 1.0 to 0.01.

There are no particular restrictions on the additives that can be added to these emulsions during the period from grain formation to the coating step, and any of the heretofore known photographic additives are preferably used, preferably 10 ^-8 to 10 ^-1 mol.
It can be added in an amount of / molAgX. For example, A
gX solvent, dopant for AgX particles (for example, Group 8 noble metal compounds, other metal compounds, chalcogen compounds, S
CN compound, etc.), dispersion medium, antifoggant, sensitizing dye (blue,
Green, red, infrared, panchromatic, ortho), supersensitizer,
Chemical sensitizers (sulfur, selenium, tellurium, gold and Group 8 noble metal compounds, phosphorus compounds, rhodan compounds, reduction sensitizers singly and in combination of two or more thereof), fogging agents, emulsion precipitants, surfactants Agents, hardeners, dyes, color image forming agents, color photographic additives, soluble silver salts, latent image stabilizers, developers (hydroquinone compounds, etc.), pressure desensitizing agents, matting agents, etc. it can.

The AgX emulsion grains of the present invention and the AgX emulsion produced by the production method can be used in all conventionally known photographic light-sensitive materials. For example, black-and-white silver halide photographic light-sensitive material [for example, X-ray sensitive material, printing sensitive material, photographic paper,
Negative film, microphone film, direct positive photosensitive material, ultrafine particle dry plate photosensitive material (for LSI photomask, shadow mask, liquid crystal mask)], color photographic light-sensitive material (eg negative film, photographic paper, reversal film, direct positive color feeling) Materials, silver dye bleaching method photographs, etc.). Further, a diffusion transfer type photosensitive material (for example, a color diffusion transfer element,
Examples thereof include a silver salt diffusion transfer element), a photothermographic material (black and white, color), a high-density digital recording light-sensitive material, and a holographic light-sensitive material.

The silver coating amount can be selected to be a preferable value of 0.01 g / m ² or more. There is also a restriction on the constitution of the photographic light-sensitive material (for example, layer composition silver / color-forming material molar ratio, silver amount ratio between the layers, etc.), exposure, development processing and photographic light-sensitive material manufacturing equipment, and emulsion dispersion of photographic additives. However, any conventionally known modes and techniques can be used. Regarding the conventionally known photographic additives, photographic light-sensitive materials and their constitutions, exposure and development treatments, photographic light-sensitive material manufacturing apparatus, etc., the descriptions in the following documents can be referred to.

Research Disclosure
Disclosure), Volume 176 (Item 17643) (12
Mon, 1978), volume 307 (item 30710)
May, November, 1989) Duffin, Photographic Emulsion Chemistry, Focal
Press, New York (1966), by Bill (EJBir
r), Stabilization of photographic silver halide emulsions
of Photographic Silver Halide Emulsions), Focal Press, London (1974),
James (TH James), Theory of the Photographic Process (The Theo
ry of PhotographicProcess) 4th Edition, Macramin (Mac
millan), New York (1977)

P. Glafkides, Chemistry and Physics of Photography (Chimie et Physique Photographiques), No. 5.
Edition, Edition da Lysine Never (Edition de
I'Usine Nouvelle, Paris (1987) Second Edition, Paul Montel, Paris (1957), Zelikmann et al. (VL Zalikman at al.), Preparation and coating of photographic emulsions (Maki
ngand Coating Photographic Emulsion), Focal Press
(1964), KR Hollister Journal of Imaging Science (Journal of Im
aging science), Vol. 31, p. 148-156 (19
1987), Muskasky (JEMaskasky), volume 30,
p. 247-254 (1986), 32 volumes, 160
~ 177 (1988), 33 volumes, 10-13 (19)
1989)

Freezer et al., The Basics of Silver Halide Photographic Process (Die Grundlagen Der Photographischen Prozesse
Mit Silverhalogeniden), Akademische Verlaggesellschaf
t), Frankfurt (1968). JCIA Monthly Report 19
1984, December issue, p. 18-27, Journal of the Photographic Society of Japan,
Volume 49, 7-12 (1986), Volume 52, 144-
166 (1989), 52 volumes, 41-48 (198)
9), JP-A-58-113926 to 113928,
59-90841, 58-111936, 6
2-99751, 60-143331, 60-
143332, 61-14630, 62-62.
No. 51, No. 63-220238, No. 63-15161.
No. 8, No. 63-281149, No. 59-133542.
No. 59-45438, No. 62-269958,
63-305343, 59-142539, 62-253159, 62-266538, 6
No. 3-107813, No. 64-26839, No. 62-
No. 157024, No. 62-192036,

Japanese Unexamined Patent Publication Nos. 1-297649 and 2-127
No. 635, No. 1-158429, No. 2-42, No. 2
No. 24643, No. 1-146033, No. 2-838.
No. 2, No. 28286, No. 3-109539, No. 3
-175440, 3-121443, 2-73
No. 245, No. 3-119347, and U.S. Pat. No. 4,63.
6,461, 4,942,120, 4,26
9,927, 4,900,652, 4,97
5,354, European Patent No. 0355568A2, Japanese Patent Application Nos. 2-326222, 2-415037, and 2-
No. 266615, No. 2-43791, No. 3-1603
No. 95, No. 2-142635, No. 3-146503.
No. 4-77261. The emulsion of the present invention is disclosed in JP-A-62-1
269958, 62-266538, 63-2
No. 20238, No. 63-305343, No. 59-14
No. 2539, No. 62-253159, JP-A-1-13.
1541, 1-297649, 2-42, 1-158429, 3-226730, 4-1
No. 51649, Japanese Patent Application No. 4-179961, European Patent 0
It can be preferably used as a constituent emulsion of the light-sensitive material of Example 508398A1.

[0046]

EXAMPLES The present invention will now be described in more detail by way of examples, but the embodiments of the present invention are not limited thereto. Example 1 An aqueous gelatin solution [H ₂ O 1.2 liter,
22 g of deionized alkali-treated gelatin (EA-Gel) having a methionine content of 48 μmol / g and 0.5 g of NaCl were added and pH was adjusted to 4.0 with HNO ₃ ], and Ag-1 liquid [in 100 ml was stirred at 30 ° C.]. 20 AgNO ₃
g, low molecular weight gelatin with an average molecular weight of 20,000 (2 MGel)
, 0.6 g of HNO ₃ (1N) solution 0.2 ml], and X-1 solution [7 g of NaCl in 100 ml, 2 MGel,
Was added at a rate of 50 ml / min for 30 seconds to form an AgCl nucleus. Then X-2 solution (KBr1.4G and 2MGel in 100 ml, the containing 0.8g i.e., Br ^-.. A content: 100%) of the hollow tube-type rubber present in the reaction solution at 100ml / min Elastic porous membrane (Number of pores 1
0 ⁴ pieces were added for 20 seconds through the opening diameter of 0.1 mm at the time of addition. Next, the temperature was raised to 40 ° C., and Ag-1 solution and X-1 solution were simultaneously mixed and added at 50 ml / min for 90 seconds. That is, (AgCl | AgBr | AgCl) nuclei were formed. Next, adjust the pH to 5.0 with 1N NaOH solution and
Aqueous solution (containing 2.1 g of NaCl) was added and the temperature was adjusted to 1
Raised to 70 ° C in 5 minutes.

After aging for 15 minutes, Ag-1 solution and X-1
The solution was simultaneously mixed and added at 10 ml / min and linear flow rate acceleration of 0.1 ml / min for 47 minutes while maintaining pCl = 1.45. It was further aged for 8 minutes. The composition of the additive solution was about AgCl _.994 B _.006 . Solution Ag-1 and solution X-3 (KBr in 100 ml)
It contains 4.2 g and 5.0 g of NaCl. That is, the Br ^- content is about 29 mol%. ) Was added at 50 ml / min for 1 minute through the hollow tubular elastic porous membrane. Next, Ag-1 solution and X-4 solution (8.4 g of KBr in 100 ml, NaCl
Contains 2.9 g. That is, the Br ^- content is about 59 mol%. ) Was added at 50 ml / min through the porous membrane for 1 minute. Then, X-5 solution (containing 20 g of KI in 100 ml) was added at 40 ml / min for 12 seconds. After aging for 3 minutes, the temperature was lowered to 40 ° C., and the sensitizing dye 1 was added by 70% of the saturated adsorption amount. After stirring for 7 minutes, a precipitating agent was added, the temperature was lowered to 28 ° C., the pH was adjusted to 4.0, and the emulsion was allowed to settle. The precipitated emulsion was washed with water, a gelatin solution was added at 38 ° C., and the emulsion was redispersed to pH 6.1 and pCl 2.8.

A part of the emulsion was sampled and a TEM image (transmission electron micrograph image) of a replica of the emulsion grains was observed. According to it, 93% of the projected area of all AgX particles
Is a right-angled parallelogram whose main plane is a {100} plane and has an aspect ratio of 3 or more. The tabular grains have an average particle diameter of 1.4 μm, an average aspect ratio of 6.2, and a diameter. The coefficient of variation of distribution (standard deviation of diameter distribution / average diameter) was 0.2. When the experiment was repeated 10 times, the variation coefficient of variation in the average particle diameter and the average aspect ratio was 0.03 or less.

[0049]

[Chemical 1]

Comparative Example 1 Instead of adding the X-2 solution in Example 1, the Ag-2 solution (10
AgNO ₃ containing 2g) and X-21 solution in 0 ml (100 m
40 ml of 62 ml / min was simultaneously mixed and added. Others were the same as in Example 1. Therefore, the halogen composition structure of the produced particles is almost the same as that of the first embodiment. ) Observation of TEM images of the obtained replicas of AgX particles shows that 90% of the projected area of all AgX particles is a tabular grain having a main plane of {100} plane, a right parallelogram and an aspect ratio of 3 or more. The average particle size of the tabular grains was 1.37 μm, the average aspect ratio was 6.0, and the variation coefficient of the diameter distribution was 0.23. When the experiment was repeated 10 times, the variation coefficient of variation in the average particle diameter and the average aspect ratio was 0.05. Therefore, the production reproducibility of the particles was better in Example 1 than in Comparative Example 1.

Comparative Example 2 The X-3 solution and the X-4 solution in Comparative Example 1 were mixed with the X-32 solution (100 ml).
The emulsion grains were prepared in the same manner as Comparative Example 1 except that 7 g of NaCl was included in the solution) and the addition of the X-5 solution was omitted. The surface of this particle is AgCl, and the composition of the produced particle is AgC.
l _.994 Br _.006 . Observation of the TEM image of the particles showed that 90% of the projected area of all the AgX particles was {10
0} plane, tabular grains having an aspect ratio of 3 or more,
The tabular grains had an average particle size of 1.4 μm, an average aspect ratio of 6.1, and a coefficient of variation of diameter distribution of 0.24.

The emulsions of Example 1 and Comparative Example 2 were each subjected to the following sensitization treatment, a thickener and a coating aid were added, and the emulsion was coated on a TAC base together with a protective layer. Next, it was dried to obtain coating samples A and B. Sensitization treatment: The emulsions of Example 1 and Comparative Example 2 were heated to 55 ° C., and NaCl solution was added to obtain pCl 2.2. Hypo was added by 2.5 × 10 ^-5 mol / mol AgX and chloroauric acid was added by 10 ^-5 mol / mol AgX, and after aging, an antifoggant (4-hydroxy-6-methyl-
1,3,3a, 7-tetraazaindene) was added in an amount of 3 × 10 ⁻³ mol / mol AgX and the temperature was raised to 40 ° C. The coated sample was exposed for 10 ^-2 seconds through a minus blue filter (light having a wavelength of 520 nm or more), developed, and stopped.
The fixing solution and the washing solution were passed through and dried. The results of the photographic characteristics are shown in Example 1 (10
0)> Comparative Example 2 (52)), which is shown in FIG.
The superiority of the particles having the structure of was confirmed. When coating sample A was cut and the cross section was subjected to scanning analysis and electron microscopic analysis, the tabular grain surface was uniformly covered with a high Br ^- content layer with a thickness of about 0.02 μm, and I ⁻ was present on the grain surface. They exist uniformly, and the coefficient of variation of their intra-particle and inter-particle distribution is 0.1.
It was within 5. The coefficient of variation of the interparticle distribution of the Br ^- content was also 0.15 or less.

Example 2 In Example 1, the Ag-1 solution and the X-1 solution were added at 10 ml / min and a linear flow rate acceleration of 0.1 ml / min for 37 minutes. 0.06 μm, the number ratio of grains containing twins and dislocations is 0.1% or less)
Same as Example 1 except that was added. Regarding the addition, 0.15 mol was added first, and after 10 minutes, the remaining 0.366 mol was added. Then, it was further aged for 20 minutes. The finally obtained particles have an average diameter of 1.48.
The average distribution was 0.2 μm, the average aspect ratio was 7.3, and the variation coefficient of the diameter distribution was 0.2. The emulsion was subjected to the same sensitization treatment as in Example 1 to prepare a coated sample C, and the same exposure and development treatments were performed. The (sensitivity / granularity) ratio is 1 with Example 1 being 100.
It was 05, which was superior.

[0054]

EFFECTS OF THE INVENTION Since the formation of the defects is performed only by adding a halogen salt solution to the host nucleus, the reaction system is further simplified. Therefore, the defects are formed more uniformly among the grains, the production reproducibility is good, and finally tabular grains having a narrower diameter distribution and excellent sensitivity and graininess are obtained. The tabular grains having the structure shown in FIG. 2 have excellent spectral sensitization characteristics and development processability.

[Brief description of drawings]

FIG. 1 shows an example of the shape of the main plane of a tabular grain.

2 (a) and 2 (b) show examples of preferable halogen composition structure in a cross section of a tabular grain. AgX ₅ and AgX ₆ are (A
Cl of gX ₆ ^- Cl of content: / AgX ₅ ^- content:) 0.8
Refers to the following relationship phases:

3 (a) and 3 (b) are transmission electron microscope photographic images at -130 ° C. showing the grain structure of tabular grains having an AgCl content of 99.6 mol% or more.

FIG. 4 shows examples of main plane shapes before and after growth of tabular grains.

Claims (2)

[Claims] 1. In a silver halide emulsion having at least a dispersion medium and silver halide grains, 30% or more of the total projected area of the silver halide grains has a {100} plane as a main plane and an aspect ratio (diameter / diameter). Tabular grains having a thickness of 1.5 or more, and the central part of the grains is the following (a),
(B) A silver halide emulsion having one or more halogen composition gap faces. (A) The gap has a Cl ⁻ content or a Br ⁻ content of 10
~ 100 mol% difference or 5-100 mol% in I ^- content
It is the difference. (B) A halogen salt in which the gap differs from the host silver halide nucleus with the halogen ion composition of the nucleus in terms of Cl ⁻ content or Br ⁻ content of 10 mol% or more, or I ⁻ content of 5 mol% or more. It is a gap surface formed substantially by a halogen conversion reaction caused by adding a solution. 2. A silver halide emulsion having at least a dispersion medium and silver halide grains, wherein 30% or more of the total projected area of the silver halide grains has a {100} plane as a main plane and an aspect ratio (diameter / diameter). Tabular grains having a thickness of 1.5 or more, and the tabular grains are the following (a) and (b):
A silver halide emulsion having a core portion and a shell portion of (A) The Cl ^- content of the core part is 60 mol% or more, the Br ^- content of the shell part is 30 mol% or more, and (Cl ^- content of the shell part / Cl content of the core part) Is 0.8 or less. (B) The shell portion is laminated substantially uniformly on at least the main plane of the core portion, and has a thickness of 3 atomic layers or more.