JPH0820696B2 - Chemical sensitization method of silver halide photographic emulsion - Google Patents

Description

TECHNICAL FIELD The present invention relates to a chemical sensitization method for silver halide photographic emulsions, and more particularly to a chemical sensitization method for controlling the formation position or number of chemical sensitization nuclei. Further, it relates to a silver halide photographic light-sensitive material using a silver halide emulsion chemically sensitized by such a method.

(Prior Art and its Problems) In general, in order to prepare highly sensitive photosensitive silver halide grains (hereinafter referred to as AgX grains), it is necessary to control the position and number of chemically sensitized nuclei serving as the photosensitization center. The limiting method is to use the halogen conversion method or the Ag conversion method at the corners and edges of AgX particles with or without adsorption of adsorbents (sensitizing dyes, antifoggants, stabilizers, etc.).
A method in which epitaxial particles are grown by adding NO ₃ and an alkali halide solution, the adsorbent is adsorbed and stabilized, and then chemically sensitized to limit the latent image forming position to the epitaxial portion.

Regarding this, JP-A-58-108526 and 57-133540
No. 62-32443 can be referred to.

A method in which an adsorbent such as a sensitizing dye is added during grain formation to introduce a defect portion into the grain, and a chemical sensitization nucleus is preferentially formed only in the defect portion.

This method is described in U.S. Patents 2,735,766 and 3,628,9.
Reference can be made to the descriptions of 60, 4,183,756, 4,225,660, Research Disclosure, Item 19227, Volume 192, P.155 (1980).

By using AgX particles having two or more kinds of crystal planes on one AgX grain and utilizing the difference in reactivity of the sulfur sensitizer to those crystal planes, the chemical sensitization nucleus is present only on one crystal plane. How to form.

Regarding this, reference can be made to FIG. 3 of J. Phot. Sci. 23, 249 (1975), Journal of the Photographic Society of Japan, Volume 47, P. 255 (1984). Regarding the method of forming the gold-sulfur sensitized nuclei only on one crystal face by utilizing this difference in reactivity, the description in Japanese Patent Application No. 62-219982 can be referred to.

A method of chemically sensitizing by adding a chemical sensitizer after adsorbing an adsorbent on AgX particles. In this method, the number of chemically sensitized nuclei is controlled, but the position is not controlled, because the chemically sensitized nuclei are formed only in the places where the adsorbent is not adsorbed. For this method, for example, JP-A-58-113926,
58-113927, 58-113928, U.S. Patent 4,439,520
No. 4,435,501, Research Disclosure, Item.17643.
Section III, JP-A-62-6251, JP-A-58-126526, JP-A-62-56949, and JP-A-62-43644.

A having two or more crystal planes on one AgX particle surface
Using gX particles, an adsorbent (face-selective adsorbent) that has selectivity for adsorbing on those crystal faces is added, and the crystal face where the adsorbent is adsorbed at a high density and the crystal face where the adsorbent is adsorbed loosely are added. After the formation, a chemical sensitizer is added to perform chemical sensitization, and a chemical sensitization nucleus is formed on the crystal surface where the adsorbent is loosely adsorbed. This method attempts to control the position of the chemical sensitization nucleus.

Regarding this, JP-A-58-113928 and Japanese Patent Application No. 62-2036
No. 35, No. 62-219982, No. 62-197741, No. 62-219983
Nos. 62-219984, 62-231373, and 62-251377 can be referred to.

AgX particles having at least two kinds of crystal planes on the surface of one AgX grain and having different halogen compositions in the surface layer of the crystal surface are used, and the selectivity for the difference in the crystal plane and the difference in the halogen composition is used. After forming an adsorbent with a high density and a crystal surface where the adsorbent adsorbed at a high density and a crystal surface where the adsorbent adsorbed sparsely, a chemical sensitizer was added to chemically sensitize the adsorbent A method of preferentially forming chemically sensitized nuclei on an adsorbed crystal face.

Regarding this, the description in Japanese Patent Application No. 62-251377 can be referred to.

In the AgX particles whose surface consists essentially of one kind of crystal plane, the surfaces have the same crystal system, and the halogen composition is different AgG particles made of AgX are used, and the adsorptivity is selected depending on the difference in the halogen composition. The adsorbent is added to the adsorbent to form a crystal surface where the adsorbent adsorbs at a high density and a crystal surface where the adsorbent adsorbs at a high density, and then a chemical sensitizer is added to chemically sensitize the adsorbent A method of preferentially forming chemically sensitized nuclei on a crystal surface adsorbed on.

Regarding this, it is possible to refer to the description of the patent application (B) (hereinafter referred to as the patent A) filed by the applicant, Fuji Photo Film Co., Ltd. on December 17, 1987.

A method of controlling both the position and number of chemically sensitized nuclei simultaneously. For example, a method combining the method of or a method combining the method of or a method combining the method.

Regarding this, the description of Patent A can be referred to.

The present invention relates to an improvement of the method of among these methods. The following problems remain in the methods of, and.

(1) From the viewpoint of more completely controlling the generation position and number of chemically sensitized nuclei, an adsorbent having a stronger adsorptive power (for example, 1-phenyl-5-mercapto-tetrazol) is used.
It is preferable to use e or a merocyanine dye having a mercapto group), but this is not preferable because it causes desensitization due to development inhibition in the subsequent development process. Further, in the case of a sensitizing dye, it is preferable to perform chemical sensitization in the adsorbed state of an aggregate that is more difficult to desorb, such as J-aggregate, but the stable state in which the aggregation has progressed is This is not preferable because it causes desensitization such as development inhibition.

(2) Usually, in order to completely control the number and position of chemically sensitized nucleation, the adsorption amount of the adsorbent is 50 to 50% of the saturated adsorption amount.
The 100% region is more preferable, but from the viewpoint of photographic properties, for example, in the case of a sensitizing dye, the optimum adsorption amount is 30 to 50% region, and there is a problem that such adsorption state cannot be utilized.

(3) In order to completely control the position where the chemically sensitized nuclei are generated, it is preferable to use an adsorbent having the largest crystal habit dependence of adsorption, but the adsorbent (for example, a spectral sensitizing dye) is In many cases, it is not the most preferable material in terms of photographic property.

(4) From the viewpoint of completely controlling the position where the chemically sensitized nuclei are formed, it may be preferable to use an adsorbent having the largest dependence of adsorption on the halogen composition. However, the adsorbent may not be the most preferable material in terms of photographic properties.

That is, in the conventional method, the adsorbent has a functional role of controlling the number and position of chemically sensitized nuclei, and a spectral sensitizing dye has a functional role of a spectral sensitizing dye. If priority is given to more complete control of the number and position of chemically sensitized nuclei, photographic properties such as development progress will deteriorate,
Both are often conflicting requirements. In principle, it is difficult to satisfy both functions.

Therefore, these problems are solved, and the number of chemically sensitized nuclei generated and their positions are well controlled, and the sensitivity is high, and the photosensitive material is composed of silver halide grains excellent in reciprocity law characteristics, development progress, and stability over time. Has the appearance of material.

(Object of the invention) The object of the present invention is to provide a method for sufficiently controlling the number and position of chemically sensitized nuclei on a silver halide grain, thereby providing sensitivity, gradation, reciprocity law characteristics, development progress, and stability over time. , Graininess, sharpness, resolution, covering power, image quality,
And a method for producing a silver halide emulsion capable of improving pressure resistance.

DISCLOSURE OF THE INVENTION The object of the present invention has been achieved by the following items.

(1) In the chemical sensitization method of a silver halide emulsion, the chemical sensitization is carried out by [adsorbing an adsorbent on the surface of silver halide grains → adding a chemical sensitizer and chemically ripening → desorbing the adsorbed adsorbent]. The process is performed by removing the desorbed product from the silver halide emulsion to remove 10 to 100% of the adsorbed adsorbent from the silver halide emulsion. Chemical sensitization method of silver emulsion.

(2) The chemical sensitization of a silver halide emulsion as described in (1) above, wherein the adsorbent is a spectral sensitizing dye, an antifoggant, a stabilizer, and a compound obtained by organically bonding them. Feeling method.

(3) The desorption changes the pH value of the emulsion to (pKa +
The chemical sensitization method as described in (1) above, wherein the chemical sensitization method is performed by setting the ratio to 0.5) or less. Here, pKa represents the acid dissociation constant or the protonation constant of the sensitizing dye.

(4) The adsorbent is a selective adsorption adsorbent, and the selective adsorption is [(the number of adsorbed molecules in the selective adsorption portion / cm ² ) / (the number of adsorbed molecules in the non-selective adsorption portion / cm ² )] / ≧ 2.5, and the chemical sensitization method of the silver halide emulsion according to (1) above, wherein the adsorbent is an adsorbent selected by the method (a) below.

(A) N kinds of emulsion coatings of single-seed emulsion particles are put into a dye solution in the same container to adsorb the dyes on the emulsion particles, and then the coatings are taken out to obtain (adsorption amount of dye / c
m ² ), and select by comparing among the n types of particles.

(5) The method for chemically sensitizing a silver halide emulsion as described in (1) above, wherein the temperature for adsorbing the adsorbent is higher than the temperature for chemical ripening.

(6) The silver halide grains are parallel double twinned grains having {100} faces at the edges, and [{111] face area / {100} face area] = 20 to 1.0. The method of chemically sensitizing a silver halide emulsion as described in (1) above, wherein

 Other preferable embodiments of the present invention are as follows.

(7) The adsorbent is a spectral sensitizing dye, and the spectral sensitizing dye added in the step after the desorption has a molecular structure different from that of the desorbed spectral sensitizing dye. A method for chemically sensitizing the described silver halide emulsion.

The AgX emulsion of the present invention is manufactured through at least the following manufacturing steps. [Grain formation → Adsorption of adsorbent on AgX emulsion particles → Chemical sensitization by adding chemical sensitizer → 10 to 100 of the adsorbent
% Desorption from AgX emulsion, removal → redispersion, addition of additives]. However, a washing step can be appropriately inserted in any part of this step. For example, the adsorbent may be adsorbed after a particle washing process and a water washing process.

In the above-mentioned conventional methods 1 to 3, the adsorbent has a functional role of controlling the number and position of chemically sensitized nuclei, and on the other hand, a spectral sensitizing dye has a functional role of a spectral sensitizing dye. However, the two functions are in conflict with each other, so a satisfactory result was not obtained.

On the other hand, in the chemical sensitization method of the present invention, these adsorbents do not have the functions of one person and two roles, but are the function-separated type chemical sensitization method of one person. That is, the adsorbent to be adsorbed before chemical sensitization is the most optimal adsorbent, adsorption amount and adsorption state from the viewpoint of controlling the number and position of chemically sensitized nuclei. Can be ignored. Then, after chemical sensitization, a part or all of these adsorbents are desorbed and removed. After washing the emulsion with water,
It is redispersed and the spectral sensitizing dye, antifoggant and stabilizer which are optimal from the viewpoint of photographic properties are adsorbed in the optimal adsorption state from the viewpoint of photographic properties.

 The present invention will be described in more detail in the order of the steps.

I Grain formation As the silver halide grain used in the present invention, I-1 is a silver halide grain in which the grain surface has substantially one type of crystal plane and one type of halogen composition.

 For example, the following particles can be mentioned.

 Cubic, octahedral particles.

Rhombohedral dodecahedron, trioctahedral, rhomboid icosahedron, tetrahedron, hexaoctahedron.

 Tabular grains prepared by a conventional method.

(JF Hamilton and LE Brady, Journal of Applied
Physics, 35 , P.414-421 (1964)], both the parallel main outer surface and the outer surface of the edge portion are {111} planes. ] Particles can be produced by the control double jet method, and the details can be referred to the following documents.

E.Moisar and E.Klein, Ber.Bunsenges.Phy.Chem., 67 , 94
9 (1963) the same, 67, 356~359. RWBeniman, J.Photogr.Sci ., 12, 121 (1964) K.Murofushi et al., International Congress of Photo
graphic Science, Tokyo (1967) Regarding the particle forming method of British Patent No. 1,335,925 and US Patent No. 4,242,445, see Joe E. Maskasky, J. Imag, Sci., 30 , 247-254 (1986). 62-42148, Japanese Patent Publication No. 55-42737, Open Technique 86-959
8, EP-171238, JP-A-62-123446, 62-123447, 62
-124550 to 62-1245523 can be referred to. However, since the adsorbent (crystal habit control agent) is adsorbed on the AgX particles as it is as described, 10 to 100% of the adsorbent is used by the "desorption / washing removal method of the adsorbent" described later. May be removed before use.

Regarding the tabular grain forming method of JP-A-58-113926 to 58-113928, Japanese Patent Application No. 61-48950,
Reference can be made to the description in JP-A 61-299155, Patent A.

I-2 AgX particles having at least two crystal faces on the surface of one AgX particle.

Specifically, (i) a tetrahedral grain having {100} faces and {111} faces. Regarding the method for producing the particles, reference can be made to the above-mentioned literature of item I-1 and Japanese Patent Application No. 62-219982.

The area ratio of the {100} plane is [area of the {111} plane / {100}
Area of surface] = 20 to 1 is preferable, and 15 to 2.0 is more preferable.

(Ii) Parallel double twin grains having {100} faces at the edges. Regarding the method for producing these particles, Japanese Patent Application No. 62-219982 and 6
The description of No. 2-251377 can be referred to.

(Iii) At least {111} plane or {100} plane and {110}, {hll} h> l, {hhl} h on one AgX grain surface
AgX particles having a total of two types of one of the> l, {kko}, and {hkl} planes. If the addition of a specific adsorbent to be added during grain growth is delayed, and crystal growth is stopped before the dodecahedron, trioctahedron, rhomboid icosahedron, tetrahedron, and hexaoctahedron are completed, Becomes Specific adsorbent in this case, dodecahedron, trioctahedral, rhomboid icosahedron, tetrahedron,
Regarding the production method of the hexaoctahedral, the description in the literature of the section I-1 can be referred to.

I-3 A silver halide grain which has at least {100} and {111} crystal surfaces on the surface of one AgX grain, and the halogen compositions of the surface layers of the crystal surface are different from each other.

Specifically, it is a tabular grain having a tetrahedral grain and a parallel twin plane. For the production method of these grains, the description in Japanese Patent Application No. 62-251377 by the present inventor can be referred to.

I-4 AgX whose particle surface consists essentially of one type of crystal plane
In the particles, AgX particles whose surfaces have the same crystal system and different halogen compositions.

The term "substantially" here means 90% or more, preferably 95% or more.

Specifically, (i) grains having different halogen compositions in the host grain portion of the tetradecahedron and the guest portion of the corner portion added later. For this,
The description in JP-A-55-124139 and the description in Japanese Patent Application No. 62-251377 regarding the preparation method can be referred to.

(Ii) Silver halide grains in which AgX layers having different halogen compositions are laminated in the direction perpendicular to the principal planes of tabular grains. Regarding this, Japanese Patent Application No. 61-253371 can be referred to.

(Iii) A tabular grain having a core portion and an additional portion having a halogen composition different from that of the core portion in the lateral direction. In this case, for example, AgBr
The iodine content of I may be core> additional, or core
Part <additional part may be used.

(Iv) A tabular grain in which a circular tabular grain is used as a host grain and AgX having a halogen composition different from that of the host grain is selectively grown only at a corner portion of the circular tabular grain.

Regarding the particles (iii) and (iv), the description in Patent A can be referred to.

(V) Tabular grains having different halogen compositions in a lateral ring shape.

The particles have the structure shown in FIG. 1 and can be produced by the production method of the above item (iii). That is, forming core particles,
Next, it can be made by growing AgX having a halogen composition different from that of the core part only in the lateral direction (direction having a trough), and then growing AgX having the same halogen composition as the core part only in the lateral direction. . PBr value during crystal growth is 1.5-
By setting it to 2.0, crystals can be grown only in the lateral direction.

In addition, in the above (i) to (iv), the halogen composition of AgBrIcl may differ depending on the iodine content and / or the cl content (however, the Br content is automatically determined if the 1 content and the cl content are determined). preferable. When the iodide contents are different, it is preferable that they are different from each other by 2 to 40 mol%, preferably 3 to 30 mol%. When the cl contents are different, 7 to 100 mol%, preferably 10 to 80 mol% of each other
It is preferable to make them different.

In this way, AgX particles of types I-1 to I-4 can be prepared.

In this case, the halogen composition of the AgX grains of I-1 to I-4 is silver chloride, silver bromide, silver iodobromide (iodine content is 0 to
Solid solubility limit, preferably 0 to 20 mol%), silver chloroiodobromide (cl
The content is 0 to 100 mol%, the I content is 0 to the solid solution limit, preferably 0 to 20 mol%), and the halogen composition is not particularly limited.

II Adsorption of adsorbent After the silver halide grains are thus formed, the adsorbent is adsorbed.

Here, the adsorbent is about 50% of the saturated adsorption amount under the chemical sensitization condition.
% When added to the AgX emulsion at 50% or more of the added amount, preferably 90 to 100%, more preferably 97 to 99.999.
% Refers to a compound adsorbed on the surface of AgX particles, and specifically refers to the following compounds.

In this case, the adsorbent is an adsorbent that adsorbs to Ag ₊ sites or halogen ion (X ₋ ) sites on the surface of silver halide grains, and specifically includes spectral sensitizing dyes, antifoggants, stabilizers, and those Are chemically bonded to each other (for example, sensitizing dye-stabilizer or sensitizing dye-pendant dye such as antifoggant).

The sensitizing dye, antifoggant and stabilizer can be selected from the compounds described below known in the photographic industry and used. Regarding the pendant dye, the description in Japanese Patent Application No. 62-219982 can be referred to.

Among these adsorbents, adsorbent bind Ag ₊ is, Ag ₊ -
It may form an adsorbent complex and act as a kind of AgX solvent during chemical aging. From this point of view, therefore, the adsorbent adsorbed on the halogen ion site is more preferable than the adsorbent adsorbed on Ag ₊ on the AgX particle surface. In the case of an adsorbent that adsorbs on Ag ₊ , its pKsp value is 10.5.
Above all, the larger one is preferable.

As a method for adding these adsorbents, only one kind of sensitizing dye, antifoggant, stabilizer and pendant dye described below may be added, or two or more kinds of additives may be mixed and added. , May be added separately.

The types of this adsorbent include the following II-1 uniform adsorption type and II
It can be classified into two types: -2 selective adsorption type.

II-1 Homogeneous adsorption type In general, the adsorption power of an adsorbent depends on the halogen composition and crystal habit of the substrate. Therefore, even if it is a uniform adsorption type, one Ag
If there are different crystal habits or different halogen composition sites on the surface of the X particles, larger or smaller selective adsorption occurs. Here, the homogeneous adsorption type means that the selective adsorption generated on one AgX particle is (the number of adsorbed molecules in the selective adsorption part / cm ² ) / (the number of adsorbed molecules in the non-selective adsorption part / cm ² ) <2.5 Refers to. Basically, the adsorption of particles of type I-1 is a homogeneous adsorption type. In this case, the adsorbent will be of uniform adsorption type even if any adsorbent described later is used.

 This type of adsorption corresponds to the case described above.

In addition, for example, as a sensitizing dye that almost uniformly adsorbs to {111} face and {100} face of AgBr, 1,1′-diethyl-2,2′- cyanine bro
mide, 3,3′-dimethyl thiazolinocyanine bromide and the like can be mentioned.

II-2 Selective adsorption type The selective adsorption type here means that the selective adsorption generated on one AgX particle is (the number of adsorbed molecules in the selective adsorption part / cm ² ) / (the number of adsorbed molecules in the non-selective adsorption part / cm ² )> 2.5 preferably 3 to 3
The adsorption is 0, more preferably 5 to 30, and basically corresponds to the cases 1 to 3 above.

In this case, the adsorbent to be adsorbed is preferably a surface-selective adsorbent or an adsorbent having different adsorption power depending on the halogen composition of the substrate.

Specifically, 3,3'-bis (4-sulfobutyl) -9-me
thylthiacarbo cyanine is preferentially adsorbed on the {100} surface,
3,3′−dimethyl thiazolino dicarbo cyanine bromide
And Br ⁻ are preferentially adsorbed on the {111} plane, and 1,1′-diethyl−
2,2'-cyanine chloride, 1,1 ', 3,3'-tetramethy-
2,2'-cyanine, anionic 9-methylthia carbocyani
The adsorption strength of ne and the like increases as the iodine content of the substrate increases.

Generally, the adsorption strength of cyanine dyes is AgCl <AgBr <AgBr
It is known to be I. Therefore, in that case, A
It is preferable to form a chemically sensitized nucleus on the priority of gBr I → AgBr → Agel.

On the other hand, antifoggants and stabilizers are generally in acid form (HL).
In the represented, its solubility product pKsp = -log [Ag ^+] [L ^-] and A
When the pKsp of gX is compared, the adsorption rate is preferentially adsorbed on the AgX particles that are larger than the pKsp value of AgX and the difference is larger, so that the adsorption rate becomes smaller in the order of AgBr 1 <AgBr <AgCl. Therefore, in that case, the adsorption amount is AgBr 1 <AgBr <
The order is AgC l. In this case, AgC l → AgBr → AgBr I
It is preferable to form the chemically sensitized nuclei thereon with the priority of.

As a specific compound, 1-phenyl-5-mercaptotetrazole (pKsp = 16.2),
5-Methylbenzotriazole (pKsp13.6), 5-Bromobenzotr
Examples thereof include iazole (pKsp12.7) and 4-Nitro-6-chlorobenzotriazole (pKsp11.2).

For the adsorption characteristics of adsorbents due to differences in halogen composition and crystal planes of these substrates, see TH James, The Theory of
the Photographic Process, Fouth Edition, Macmillan, N
ew York, 1977, Chap.9, Chap.1 , Chap.13. A.Herz and J.Helling, J.Colloid Interface Sci., 22, 3
91 (1966). SLScrutton, J.Phot.Sci., 22 , 69 (1974), J, Nys, Dye Sensitization, Bressanone Symposium, Focal Press, London, 1970, P.26-43, 57-6
5. T. Tani, Journal of Imaging Science, 29 , 165 (1985). Japanese Patent Application No. Sho 62-197741, No. 62-219983, No. 62-219984
Nos. 62-231373 and 62-251377 can be referred to.

Practically, it can be investigated by measuring Langmuir adsorption isotherms of various adsorbents for cubic particles, octahedral particles, and particles having different halogen aggregability, which is described in the book by TH James above. Can be used as a reference.

More practically, the following method is effective. N kinds of emulsion coatings of single seed emulsion particles such as cubic grains, octahedral grains, grains having different halogen compositions (for example, cut products of emulsion coating film or emulsion coating dry plate) are put in a dye container of the same container, Adsorb the dye on the particles. Next, the coated material is taken out, the liquid adhering to the surface is removed, and then the (dye adsorption amount / cm ² ) of the particles is measured, and the (dye adsorption amount / cm ² ) between the n kinds of particles is compared. To do. Here, it is preferable to take out the coated material after the adsorption equilibrium is reached. Here, the adsorption equilibrium refers to a state in which there is no change in the amount of dye adsorbed between the coated materials even if it takes more time. The adsorption is preferably performed with stirring. As a method for removing the adhered liquid, washing with cold water within a short time (for example, with water at 5 to 45 ° C.
Washing with water for up to 300 seconds) is preferred. As a method for measuring the amount of adsorption, the Kubelka-Munk method, a method of placing a sample in an integrating sphere to determine the amount of light absorption, and the like are preferable.

The adsorbent to be adsorbed is preferably an adsorbent that strongly adsorbs from the viewpoint of controlling the number and position of chemically sensitized nuclei.

The adsorption force is usually represented by the adsorption free energy (ΔG), and can be conveniently determined from a Langmuir adsorption isotherm curve.

In addition, the adsorption power of sensitizing dyes and additives to silver halide is not limited to the crystal habit and halogen composition of the substrate, but various atmospheres of emulsion (emulsion pH, pAg, coexistence of temperature adsorption promoter, etc.)
Is known to depend on. Therefore, by utilizing the knowledge, the adsorption strength of the sensitizing dye and the additive can be adjusted.

For example, TH James, The Theory of th
e Photographic Procsess, Fourth Edition, Macmillan, N
The description in ew York, 1977, Chap.9, Chap.1, Chap.13 can be referred to.

On the contrary, when chemical sensitization is performed, when the optimum emulsion conditions for chemical sensitization (eg pH, pAg, temperature, coexistence of other additives) are determined, an adsorbent that strongly adsorbs under those conditions Is preferably selected.

In general, as the adsorptive power increases, the sensitizing dye
J aggregates are easily formed, but J aggregates are preferable because they more sufficiently prevent the formation of chemically sensitized nuclei.

Also, as a method of adsorbing the sensitizing dye, low temperature (30 ~
When adsorbed at 45 ℃) for a short time, the dye is almost fixed at the position where it was adsorbed first, so it adsorbs in a more random pattern.

Then, when it is chemically aged at a high temperature (50 to 80 ° C),
By repeating adsorption and desorption, aggregates such as J aggregates grow. Thus, during the chemical ripening, when the dye repeatedly adsorbs and desorbs and the aggregate grows, a chemical sensitizing nucleus is not formed at the position where the adsorbent is adsorbed during the chemical ripening.
It is not preferable because del cannot be established.

However, adsorption equilibrium is rapidly achieved by addition of high temperature (50-80 ° C), and the dye is most stable (in other words, Gibbs free energy change ΔG is the largest) at the final adsorption position and adsorption state (J-aggregate, etc.). ) Is absorbed. And
Even if the chemical ripening is subsequently performed, the adsorption state is less likely to change during the chemical ripening, and a model in which the chemical sensitized nuclei are not formed at the position where the adsorbent is adsorbed is preferable.

In order not to change the adsorption state of the adsorbent during the chemical aging, the adsorption of the adsorbent is performed at a temperature higher than the temperature during the next chemical aging (preferably 3 ° C or higher, more preferably 6 to 60 ° C).
And, it is preferable to take a time of 7 minutes or more (7 to 60 minutes).

Further, it is preferable to form an aggregate such as a J-aggregate of the sensitizing dye in the final adsorption state. Adsorption of the adsorbent is generally in the equilibrium relationship of adsorption and desorption [for this, see T. Tani, J. Imaging Sci., 29 , 165 (1985).
17 can be referred to], but this desorption frequency is due to molecular adsorption> aggregate adsorption.

Regarding the adsorption amount of the adsorbent, in the present invention, for example, a sensitizing dye can be used in a so-called desensitization region and a so-called large addition region.

Therefore, the addition amount is not particularly limited, but practically 10 to 150% of the saturated adsorption amount, preferably 30 to 100%, particularly preferably
A 50-100% area is used.

As described above, in the present invention, in order to desorb and remove 10 to 100% of the adsorbent adsorbed after the chemical sensitization, the adsorption is performed by selecting the optimum adsorbent from the viewpoint of controlling the number and position of the chemical sensitized nuclei. It has an advantage that it can be used in an optimal adsorption amount and an optimal adsorption state.

In the present invention, as a method of adsorbing the adsorbent, as described above, only one of the II-1 type adsorbent or the II-2 type adsorbent may be added. The adsorbents may be mixed and added, or may be added separately.

When both adsorbents are added, the II-1 type adsorbent plays a role in controlling the number of chemosensitized nuclei, and the II-2 type adsorbent plays a role in controlling the position of chemosensitized nuclei. do.

In the case of the improvement of the above-mentioned method, after adsorbing the adsorbent, the epi particles are grown on the host particles. Regarding the method of forming the epi-particles, JP-A-58-108526 and 59-13
No. 3540, No. 55-124139, No. 59-162540, No. 62-32443
No. 62-7040 and European Patent No. 0019917A can be referred to.

III Chemical sensitization After the adsorbent has been adsorbed in this manner, chemical sensitized nuclei are formed on the crystal plane where the adsorbent is not adsorbed.

As the chemical sensitization method, any of the following methods is appropriately used.
Can be selected and used.

a. Commonly used chemical sensitization method. That is, the temperature of the emulsion
After 40 to 80 ℃, after adding the sulfur sensitizer and gold sensitizer,
Method of aging for 20 to 80 minutes. Regarding the conventional chemical sensitization method, reference can be made to Kenichi Kushita, Nikkan Magazine 50 , 108 (1987), and the description of the literature described later.

The chalcogenide sensitizers and gold sensitizers as the chemical sensitizers are preferably added in an amount of 10 ⁻³ to 10 ⁻⁸ mol / mol AgX,
^-4 to 10 ^-7 mol / mol AgX.

b. Area-selective chemical sensitization. In AgX grains having at least {111} faces and {100} faces on one grain surface, a face-selective sulfur sensitizer that reacts preferentially on the crystal faces for which chemical sensitizing nuclei are preferentially formed. Chemically aged using
This is a method in which after 80% or more of the reaction is completed, or after the residual sulfur sensitizer is washed and removed, a gold sensitizer is added for aging.

In this case, gold-sulfur sensitized nuclei are preferentially formed on one crystal face. Regarding the surface selective reactivity of the sulfur sensitizer and this method, the description in Japanese Patent Application No. 62-219982 can be referred to.

c. In sulfur sensitization and gold sensitization, if the total amount of the chemical sensitizer to be added is added instantaneously, the reaction of the chemical sensitizer spreads over the entire crystal plane, and the surface selectivity tends to be reduced. Therefore, it is effective to add it over time. The preferred addition time is 3-40 minutes. It is preferable to add the chemically sensitized nuclei formed in the first 3 minutes at a rate at which new chemically sensitized nuclei are not formed.

Whether or not new chemically sensitized nuclei are generated can be confirmed by using the suppressed development method described later.

d. A method of carrying out the chemical sensitization reaction at a low temperature. Usually, the chemical sensitization reaction is carried out in the range of 50 to 75 ° C. However, under this condition, the reversible reaction of the adsorbent in the adsorbed state and the desorbed state occurs more frequently, so that the model in which the chemical sensitized nucleus is not formed at the position where the adsorbent is adsorbed cannot be established. This tendency becomes more remarkable as the temperature increases. On the other hand, in the method of performing the chemical sensitization reaction at a low temperature, the adsorption position of the adsorbent is more firmly fixed, and the generation position and number of the chemical sensitization nuclei are more accurately controlled.

In this case, the preferable temperature is 25 to 50 ° C, more preferably 30 to 45 ° C. In this case, the reaction rate of chemical sensitization becomes slow, but it can be dealt with as follows.

(B) When the emulsion is ripened with a low pAg, the reaction speed will be high. In this case, the pAg is preferably 4-8.

(B) When the addition amount of the chemical sensitizer is increased, the required amount of the chemical sensitization nucleus is generally generated in a shorter time as expected from the reaction rate equation. In this case, the amount of unreacted residual chemical sensitizer increases, but since it can be removed in the next water washing desorption step,
It doesn't matter.

(C) Use a chemical sensitizer with a fast reaction rate.

Specifically, 5-benzylidene-3-ethylrhodanine
Such as rhodanine and 3-allyl-4-oxo-oxazolidine-
Thiones such as 2-thione can be mentioned.

Regarding (a) and (c), the description in Reference Example 1 of Japanese Patent Application No. 62-219982 can be referred to.

Next, a chemical sensitizer is added to form chemical sensitization nuclei on the epi grains or at the boundary between the epi grains and the host grains.
As the chemical sensitization method in this case, any one of the chemical sensitization methods of a to b can be appropriately selected.

IV Desorption / Removal of Adsorbent After controlling the generation position and number of chemically sensitized nuclei in this manner, a part or all of the adsorbent is desorbed / removed in the present invention. When the adsorption amount is too large and the adsorption amount of the dye is in the desensitizing dye amount region, it is preferable to desorb and remove the dye to the optimum addition amount, or to adsorb the dye of the optimum addition amount after the desorption and removal.

Although preferable from the viewpoint of controlling the generation position and number of chemically sensitized nuclei, an adsorbent which is not optimal in terms of photographic properties is desorbed / removed in this step.

In this case, the proportion of the adsorbent to be desorbed is 10 to 100 mol%, preferably 25 to 100 mol%.

The adsorption equilibrium formula for antifoggants and stabilizers is Can be written as The left balance equation is specified in pKa and the right balance equation in pKsp. Lowering the pH of the emulsion to below pKa, of the left formula equilibrium shifts to the left, [L ^-]
The concentration decreases and the adsorbed L ⁻ is desorbed.

Most antifoggants and stabilizers have pKa values above pH 3. The pKa value of each compound is THJames, The Theory of
The Photographic Process, Fourth Edition, Macmilla
n, New York, 1977, Chap. 1 can be referred to.

When desorbing the adsorbent, the preferred pH range is (pKa + 0.5) to (pKa-3), preferably (pKa + 0.25) to (pKa-3), more preferably the pKa value of the adsorbent used. Is represented by (pKa) to (pKa-2). The lower the pH, the faster the desorption. However, when the pH is lowered to 1.5 or less, the hydrolysis of gelatin rapidly proceeds and the chemically sensitized nuclei are affected, so that the pH range of 1.5 to 6 is practically preferable. The pH at which the adsorbent is desorbed and the pH at which the AgX emulsion is washed with water may be the same or different. The adsorbent desorption step and the emulsion water washing step can be combined.

In the present invention, it is preferable to remove the adsorbent that has been desorbed by washing with water after desorbing the adsorbent.

On the other hand, when desorbing the adsorbed sensitizing dye, the following method can be used.

i A method in which a sensitizing dye is protonated, solubilized, and then desorbed.

For example, cyanine is protonated and solubilized as follows.

The pH at which half the amount present is protonated is expressed as pKa. The sensitizing dye having a pKa value in the range of pH 1.5 to 6 can be desorbed by adjusting the pH of the emulsion to 1.5 to 6.

ii A method utilizing a substitution desorption reaction with a positively charged gelatin molecule.

When gelatin is brought to a pH below the isoelectric point (pH 4.9 or below),
It has a positive charge and substitutes for adsorption on the halogen ion site on the surface of AgX particles. This is a method of desorption utilizing this reaction.

 The preferred pH range in this case is pH 1.5 to 5.0.

iii A method utilizing a substitution / desorption reaction with Ag ⁺ or Br ⁻ .

Cationic dyes, the higher the Ag ⁺ concentration of washing Ag ⁺
And replace it.

On the other hand, dyes such as merocyanine which has an affinity for Ag ⁺ are B
r ^- The higher the concentration, Br ^- and to replace desorption. This is a method of utilizing this reaction to desorb the dye. The Ag ⁺ concentration and the Br ⁻ concentration are preferably in the range of 10 ^−1.8 to 10 ⁻⁶ M / l.

In this case, the AgX emulsion is treated with a low pA at pH 6 to 7 which is usually used.
Low pH (1.5-5.0) because fogging occurs in the emulsion when g is set.
It is preferable that Also, at low pAg, the surface of AgX particles becomes Ag ⁺ charged, so that the charged dye is difficult to adsorb. Especially for dyes with pKa values of 1.5 or less,
This method is preferred.

iv A method of desensitizing the sensitizing dye by making it Ag ⁺ , solubilizing it.

This is a method in which the above i is converted to Ag ⁺ instead of protons and solubilized and desorbed.

In this case, the Ag ⁺ concentration is preferably in the range of 10 ^−1.3 to 10 ⁻⁶ M / l.

v A method of desorbing a dye by adding an antifoggant or a stabilizer.

For example, glutathione, thiourea and its derivatives, 5-
Phenylmercaptotetrazole, tetrazaindene,
Substitution or desorption of part or all of the dye with benzotriazole, benzimidazole, etc. (pH at this time is preferably a pH above the pKa of the antifoggant or stabilizer, usually pH 4-9), and then fog prevention Adjust the pH below the pKa of the agent or stabilizer to desorb the antifoggant or stabilizer.

Since there are quite a few dyes whose pKa is less than 1.5, the method i may not be used. On the other hand, for antifoggants and stabilizers
Since pKa is 3.0 or higher in most cases, this method can effectively desorb the dye even in such a case.

In the above, when washed with water at low pH and low pAg conditions, i-iv
By receiving the synergistic effect of, the effective desorption of the cationic color can be performed.

The preferred pH range is pH 1.5 to 6.0, and the pAg range is 1.8 to 6.0.

As a general tendency, the magnitude of the pKa value of the sensitizing dye depends on the size of the imidazoline dye such as benzimidazolocarbocyanine>
The thiacyanine dye> oxacyanine dye, and the imidacyanine dye is preferable because it can be desorbed at a higher pH value. In addition, the order is also in terms of the stability of the dye that has been desorbed by protonation or silver ionization, and the imidacyanine dye is preferable also from this viewpoint. When the desorbed dye decomposes quickly, it is preferable to quickly remove the desorbed dye by washing with water. In this case, "quick" means within 1 hour.

For the pKa values of various sensitizing dyes and the above i to iv,
THJames, The Theory of The Photographicd Process,
Fourth Edition.Macmillan, New York, 1977, Chap.8,9, AHHerz, Phot, Sc
i, Eng., 18 , 207 (1974), P. Beretta and A. Jaboli, Phot.
Sci.Eng., 18 , 197 (1974), S.Boyer and L.Pichon, Phot.Sci.Eng., 18 , 555 (197
4), J.Nys, Dye Sensitization, Bressano Symposium, Focal P
The description of ress, London, 1970, P.26-43, 57-65. can be referred to.

After the desorption of the adsorbent, or when the desorption and the water washing are carried out simultaneously, the emulsion water washing method has been conventionally used (i) Noudel water washing method, (ii) sedimentation water washing method by centrifugation, (iii) Washing method in which a settling agent is added to settle, (i
v) Settling water washing method using modified gelatin such as phthalated gelatin, (v) Ultrafiltration method (Japanese Patent Publication No. 59-43727), etc. (For details, see GFDuffin. “Photographic Emulsion Chemistry,” Fo
In addition to cal Press.London.1966 and the literature below), (vi) "a method of making 70% or more of the dispersion medium at the time of washing with low molecular weight gelatin (molecular weight 2000 to 40,000) and washing with sedimentation" is effective.

This is because gelatin having an average molecular weight of about 100,000 is usually used as the dispersion medium of a silver halide emulsion, but in that case, even if stirring is stopped, the emulsion does not easily settle,
When the dispersion medium is low molecular weight gelatin, it is a water-washing method that utilizes the fact that it sediments without adding a precipitating agent. The emulsion settles in the pH 1.5-5 region.

The washing method of (iii) is usually carried out near pH 4.0, but KN
When an irrelevant salt such as O ₃ is added, it becomes flocked at pH 4 to 1.5, precipitates, and can be washed with desorption water. Therefore, the pH can be selected by selecting the salt concentration. In that case, the preferable salt concentration is 0.5 to 10% by weight. However, the salt concentration in this case also includes salts such as KNO ₃ generated during AgX particle formation.

Once the emulsion is flocked, the flock stabilizes and the pH
The flock does not redissolve in the 5 to 1.5 region. Therefore, the emulsion can be washed with water in the pH range of 1.5 to 5 by the method (iii).

In addition, in this washing step, it is preferable that the unreacted residual chemical sensitizer is also washed and removed. In this case, as the washing water, -log (X ^-.] = PX = 1.0 to 6.0 using an aqueous halide salt solution to information about a method of removing the residual chemical sensitizers, the description of Japanese Patent Application No. Sho 62-219982 Can be used as a reference.

Further, in order to remove the unreacted residual gold sensitizer simultaneously with water, it is preferable to wash with an aqueous solution containing a complex that forms a stable complex with gold ions. In this case, a complexing agent that forms a gold complex having a large stability constant can more effectively remove the residual gold sensitizer in gelatin, but can be appropriately selected according to the purpose of use. As a specific example, sulfite, thiocyanate, Br ^- salt or the like can be used. For stability constants of various gold complexes, see WPRapson and T. Groenewald, Gold Usage, Academic Pr.
The description of ess, (1978), P.200 can be referred to.

The removal of the chemical sensitizer by washing with water may be carried out before or at the same time as the above-mentioned desorption and washing with water of the adsorbent, or after the desorption and washing with water is completed. When the unreacted residual chemical sensitizer is removed, the stability of the emulsion over time is improved.

V Redispersion and Addition of Additives After the adsorbent is partially or completely washed off with water in this manner, the emulsion is redispersed. When this emulsion is redispersed, a treatment for recovering the surface reduction sensitization performance lost by the above-mentioned low pH treatment may be carried out. The pH of the emulsion when redispersed is 5 to 30 minutes, pH 6.5 to 9, temperature 35 to 60 ° C.
It is achieved by aging in the state of. Add the most optimal spectral sensitizer for the spectral sensitization of the emulsion in the optimal amount and adsorption state, and the optimal antifoggant and stabilizer for the emulsion system in the optimal adsorption state. You can

The spectral sensitizing dyes and additives added at this time are the same as those mentioned above.
II-1 and II-2, those that adsorb on the AgX particle surface without selectivity, those that selectively adsorb on specific crystal planes,
Any of those that selectively adsorb the halogen composition on the adsorption surface can be appropriately selected and used. In addition, the above-mentioned pendant dye can be used as an emulsion additive. The additive in this case is not limited to the control of the chemically sensitized nuclei, and the optimum additive can be selected in consideration of the photographic property and the development progress.

As a method of adding these additives, only one kind of sensitizing dye, antifoggant, stabilizer and pendant dye may be added, or two or more kinds of additives may be mixed and added, or separately. May be added to.

The lowest cost step in the method for producing the AgX emulsion of the present invention is AgX grain formation → adsorption of adsorbent → chemical sensitization → desorption / washing removal of adsorbent up to the optimum addition point + remaining unreacted chemical sensitizer Removal → redispersion.

From the viewpoint of preventing the latent image from being destroyed by the dye holes, it is preferable that the position where the chemical sensitizing nucleus is formed and the position where the sensitizing dye is adsorbed are separated from each other. Therefore, in this case, it is preferable to selectively adsorb the sensitizing dye or the above-mentioned pendant dye onto the crystal surface or the halogen composition surface on which the chemically sensitized nuclei are not formed. Regarding the selective adsorption method of this sensitizing dye, the above-mentioned item II-2 can be referred to. For details of the effect, see
The description of No. 62-251377 can be referred to.

It is difficult to directly observe the chemically sensitized nuclei in the AgX particles in which the position and / or number of the chemically sensitized nuclei of the present invention are controlled.

However, it was exposed to a silver halide emulsion coating, the latent image was crystallized in the chemically sensitized nuclei (photosensitive nuclei), and the suppressed development was performed, and the suppressed development nuclei were made visible under an electron microscope, and then the suppressed development was performed. The above ratio of chemically sensitized nuclei can be obtained by counting the number of nuclei.

See DC Birch et al., Journal of Phot for this approach.
ographic Science, 23, P.249-256 (1975).

Here, the chemical sensitization nucleus is a chemical sensitization nucleus consisting of sulfur, selenium, tellurium, gold and a Group 8 noble metal compound alone or in combination, most preferably a gold-sulfur sensitization nucleus. It is usually called a sulfur sensitized nucleus, a gold sensitized nucleus, a noble metal sensitized nucleus, or a combination thereof, and the details can be referred to the literatures described later.

The silver halide grains of the present invention can be used as an emulsion by the above-mentioned silver halide grains themselves, but a core / shell type direct inversion emulsion can be formed by using the grains as a core and used. Regarding this, Example 13 of Japanese Patent Application No. 61-299155 and U.S. Pat. Nos. 3,761,276 and 4,269,927,
Reference can be made to No. 3,367,778.

Also, a shallow inner latent emulsion may be formed using the grains as a core. Regarding this, JP-A-59-133542,
Reference may be made to British Patent No. 145,876.

Also, H ₂ O ₂ until the particles of the gold sensitizer ripening is completed, adding an oxidizing agent such as peroxy acid, then, a method of adding a reducing substance, after gold sensitization ripening, in the photosensitive material of A method of reducing free gold ions can be used. Regarding this, JP-A-61-3134, 61-3136, 60-96237,
61-219948, 61-219949, Japanese Patent Application No. 61-184890,
Reference can be made to Nos. 61-1839949 and 60-96237.

The spectral sensitization of the grains is described in Japanese Patent Application No. 61-51396.
The spectral sensitization methods described in 61-284271 and 61-284272 can be referred to.

Examples of the sensitizing dye, antifoggant, and stabilizer that can be used as an adsorbent or an additive after redispersion in the AgX emulsion production method of the present invention include the following.

Examples of the sensitizing dye include cyanine dyes, merocyanine dyes, complex cyanine dyes, complex merocyanine dyes, holopolar cyanine dyes, hemicyanine dyes, styryl dyes, hemioxonol dyes, oxonols, polymethine dyes containing streptocyanin. it can.

Examples of the antifoggants and stabilizers include tetrazaindenes, azoles such as benzothiazolium salts, nitroindazoles, nitrobenzimidazoles, chlorobenzimidazoles, bromobenzimidazoles, mercaptothiazoles, and mercapto. Benzimidazoles, aminotriazoles, benzotriazoles, nitrobenzotriazoles, mercaptotetrazoles (particularly 1-phenyl-5-mercaptotetrazole) and the like, and also mercaptopyrimidines, mercaptotriazines, for example thioketo compounds such as oxazolithion, Furthermore, benzenethiosulphonic acid, benzenesulphonic acid, benzenesulphonic acid amide, hydroquinone derivatives, aminophenol derivatives, gallic acid derivatives, ascorbic acid derivatives Mention may be made of the body.

For more specific compounds, the documents described in Section VI can be referred to.

Other specific compounds of the selective adsorption type adsorbent described in the paragraph II-2 of the present invention include, for example, {11} with respect to {100} plane of AgBr.
5,5'-Dichloro-3,3'-diethylthiacyanine bromide, 5,5'-dichloro-3,3'-di (4-sulfobutyl)-
Thiacyanine Na salt, 5-methoxy-4,5-benzo-3,3'-di (3-sulfopropyl) thiacyanine Na salt, 5,5'-dichloro-3,3'-diethylselenacyanine iodide, 5, 5'-dichloro-9-ethyl-3,3'-di (3-sulfopropyl) thiacarbocyanine pyridinium salt, anhydro-5,5'-dichloro-9-ethyl-3-
(4-sulfobutyl) -3'-ethyl hydroxide, 1,1'-diethyl-2,2'-cyanine bromide, 1,1'-dibenzil-2,2'-cyanine perchlorate, AgBr 9-methyl-3,3'-di (4-sulfobutyl) -thiacarbocyanine pyridinium salt as an adsorbent which is more selectively adsorbed on the {100} plane of Diphenyl-9-ethyl-3,3'-di (2
-Sulfoethyl) -oxacarbocyanine Na salt, 5-chloro-5'-phenyl-9-ethyl-3- (3
-Sulfopropyl) -3 '-(2-sulfoethyl) oxacarbocyanine Na salt, 5,5'-dichloro-9-ethyl-3,3'-di (3-sulfopropyl) oxacarbocyanine Na salt, 5, 5'-dichloro-6,6'-dichloro-1,1'-diethyl-3,3'-di (3-sulfopropyl) imidacarbocyanine Na salt, 5,5'-diphenyl-9-ethyl-3 , 3'-di (3-sulfopropyl) thiacarbocyanine Na salt and the like can be mentioned.

VI Others The additives that can be added between the grain forming step and the coating step in the AgX emulsion of the present invention are not particularly limited, and various additives can be added as necessary.

Chemical sensitizers, spectral sensitizing dyes, antifoggants, metal ion dopes, silver halide solvents, stabilizers, dyes, color couplers, DIR couplers, binders, hardening agents, coating aids, sensitizers that can be added. Sticky agent, emulsion precipitation agent, plasticizer,
Dimension stability improver, antistatic agent, fluorescent whitening agent, lubricant, matting agent, surfactant, ultraviolet absorber, scattering or absorbing material,
Hardening agents, anti-adhesion agents, photographic property improving agents (for example, development accelerators, contrast enhancers, etc.), developers, and other photographically useful fragments (development inhibitors or accelerators, bleaching accelerators, developers, etc.)
Silver halide solvents, toners, hardeners, antifoggants, competitive couplers, couplers that release chemical or spectral sensitizers and desensitizers, image dye stabilizers, self-inhibiting developers, and their use, In addition, supersensitization in spectral sensitization, halogen acceptor effect and electron acceptor effect of spectral sensitizing dye, action of antifoggant, stabilizer, development accelerator or inhibitor, and others, in the production of the emulsion of the present invention. Manufacturing equipment used, reaction equipment, stirring equipment, coating, drying method, exposure method (light source, exposure atmosphere, exposure method), photographic support, microporous support, undercoat layer, surface protective layer, matting agent, intermediate layer , Anti-halation layer, photographic processing agent, and photographic processing method, Research Disclosure Magazine, Volume 176, December 1978 issue (Item 17643), Volume 184, August 1979 issue (Item
No. 18431), Volume 134, June 1975 (Item 13452),
Product Licensing Index, Vol. 92, 10
7-110 (December 1971), JP-A-58-113926, 58-1139
27, 58-113928, 61-3134, JCIA Monthly Report 1984
, December issue P18-27, THJames, The Theory of The Pho
tographic Process, Fourth Edition, Macmillan, New Yor
k, 1977, Making and Coatin by VL Zelidman et al.
g Photographic Emulsion (The Focal Press, 1964
Year), and the description in JP-A-62-6251 can be referred to.

The silver halide emulsion of the present invention can be provided on the support together with other emulsions, a protective layer, an intermediate layer and a filter layer in one or more layers (for example, two layers or three layers) if necessary. Further, it is not limited to one side of the support, and may be provided on both sides. It is also possible to superpose different color sensitive emulsions.

Regarding this layer structure, other, JP-A-61-3134,
The description in Japanese Patent Application No. 61-299155 can be referred to.

The silver halide emulsion of the present invention can be used as a black-and-white silver halide photographic light-sensitive material (for example, X-ray light-sensitive material, squirrel-type light-sensitive material, negative film for black-and-white photographing) or a color photographic light-sensitive material (for example,
Color negative film, color reversal film, 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), a photothermographic material (black and white, color).

(Effects of the present invention) The function-separated type chemical sensitization method of the present invention has the following features (a) to (g) as compared with the above-mentioned conventional methods (1) to (3).

(A) Regarding the amount of the adsorbent added, in the present invention, a part or the whole amount of the additive is washed and removed after chemical sensitization. Therefore, at this stage, only from the viewpoint of controlling the number and position of the chemically sensitized nuclei. The addition amount can be selected. So, for example,
The sensitizing dye can be used in the so-called desensitization region and the so-called large addition region.

(B) Regarding the adsorption strength of the adsorbent, the adsorbent that strongly adsorbs more completely blocks the formation of chemosensitized nuclei,
preferable. In the present invention, since part or all of the additive is washed off with water after chemical sensitization, 1-phenyl-6-mcrcapto-
Even compounds having a strong development adsorption effect such as tetrazole and merocyanine dyes can be preferably used as the adsorbent.

(C) In order to control the generation position and number of chemically sensitized nuclei, it is preferable to adsorb the adsorbent in a stable aggregation state with less desorption frequency such as a J-aggregate of the sensitizing dye. In the present invention, because of the function separation type, such an adsorbed state can be used without being bothered by the subsequent photographic property.

(D) In the present invention, since almost all of the adsorbent is removed by washing with water after the chemical sensitization, the sensitizing dye for the red sensitive layer may be adsorbed to the emulsion for the green sensitive layer of the color film to be chemically sensitized. There is no problem even if chemical sensitization is carried out by adsorbing a sensitizing dye for the green-sensitive layer or the red-sensitive layer to the emulsion for the blue-sensitive layer. That is, the adsorbent can be selected from a wider range of adsorbents regardless of the color sensitivity. In the conventional blue-sensitive layer emulsion which is used without using a sensitizing dye,
Although the sensitizing dye could not be used as the adsorbent in the above method, it can be used freely in the present invention.

(E) In addition, when adsorbing the above-described surface-selective adsorbent or halogen composition-selective adsorbent, the optimum adsorption is obtained from the viewpoint of controlling the generation position and number of chemically sensitized nuclei without being restricted by the photographic property. The agent can be selected. Therefore, there is a merit that the selection range of the adsorbent becomes wider.

(F) If the unreacted residual chemical sensitizer is also removed by washing with water after desorption and washing with water after the chemical sensitization, the unreacted residual chemical sensitizer remaining in the sensitized material is Few.
Therefore, it has excellent stability over time.

(G) After chemical sensitization, the adsorbent is desorbed, washed and removed, and the sensitizing dye, antifoggant and stabilizer to be added next are selected from the viewpoint of photographic properties, the optimum compound, addition amount and adsorption state. You can

Due to the effects of (a) to (g), it is possible to obtain a light-sensitive material comprising AgX particles having a small latent image dispersion, high sensitivity, reciprocity law characteristics, development progress, gradation, stability over time, and image quality.

(Examples) Hereinafter, the present invention will be described specifically with reference to Examples, but the embodiments of the present invention are not limited thereto.

Example-1 An aqueous gelatin solution (955 ml H ₂ O, 40 g gelatin,
pBr 2.8, pH 6.0), the temperature was raised to 75 ° C, and the AgNO ₃ aqueous solution (0.7 g AgNO ₃ in 100 ml) and the kBr aqueous solution were added by the quantitative addition method at 4 ml / min for 10 minutes. Added at 28 ml / min for 7 minutes. The pBr value was kept at 2.8 during the addition. Then kBr = 3
g was added, Ag-N silver potential -25 mV, during the AgNO ₃ solution (100ml
(Including 10 g of O ₃ ) and an aqueous solution of kBr, the initial addition rate is 3 ml /
Min, final addition rate 20 ml / min for 50 minutes, add CDJ, and add 0.8
Preparation of μm octahedral AgBr emulsion grains, washing with water, pH 6.4, pA
dispersed with g8.6. This emulsion was heated to 60 ° C., and a sensitizing dye (Dye 1) having the following structural formula (pKa value when adsorbed on {111} face of AgBr was 4.6) was adsorbed at 90% of saturated adsorption amount, and after 20 minutes, , J after growing aggregate (this state is the desensitizing dye amount region in terms of dye addition amount, and the adsorption state is
J aggregate has grown and is in the adsorption state in the desensitized area), and then
_{Na 2 S 2 O 3 · 5H} 2 O aqueous solution only ^{1.0 × 10 -5 mol / mol AgGr} , 10
After 5 minutes, 5 minutes later, a gold sensitizer (gold-thiocyanic acid complex) was added by 0.4 × 10 ⁻⁵ mol / mol AgBr, followed by aging for 50 minutes. Next, the temperature was lowered to 35 ° C., the pH was lowered to 3.0, the sensitizing dye was desorbed by almost 100%, the emulsion was washed with water at pH 3.0, and the desorption / water washing process was repeated twice. Next, re-disperse the emulsion and bring it to 40 ° C. to adsorb Dye 2 at 38% of the saturated adsorption amount (optimum addition amount for sensitivity), and then to prevent fog inhibitor TAI (4-hydro).
xy-6-methyl-1,3,3a, 7-tetraazaindene) and a coating aid were added (coating silver amount: 1.5 g / m ² , base: polyethylene terephthalate film).

Example-2 The same as Example 1 except that Dye1 was added to the emulsion at 40 ° C. for 20 minutes, the temperature was raised to 50 ° C., and the chemical sensitizer was added. To prepare an emulsion coating film.

Comparative Example-1 The same octahedral AgBr emulsion as in Example 1 was used, and the emulsion temperature was set to 40.
C., 38% of the saturated adsorption amount of Dye 2 was added, and after 20 minutes, the temperature was raised to 50.degree. C., the same chemical sensitizer as in Example 1 was added, and after chemical sensitization, the temperature was set to 40. The temperature was lowered to ℃, the antifoggant TAI and a coating aid were added and coating was performed.

The emulsion coating films of Examples 1 and 2 and Comparative Example 1 were coated with 500 nm.
The above-mentioned light was passed through the filter to carry out a wet exposure for 1/1000 seconds, followed by development with a MAA-1 developer at 20 ° C. for 10 minutes. The sensitivities obtained from the obtained characteristic curves are shown in Table 1.

On the other hand, the emulsion coating films of Examples 1 and 2 and Comparative Example 1 were exposed for 1 second (three times the exposure amount giving the maximum density in the sample of Example 1) through a red filter which transmits light of 550 nm or more, After developing with Birch's suppressed developer at 20 ℃ for 6 minutes, gelatin is removed and the TE of the particles is prepared by the replica method.
The M image was observed. The development starting point per particle of the particles of Examples 1 and 2 and Comparative Example 1 was counted. The results are shown in Table 1.

This result indicates that (i) the optimum addition amount of the sensitizing dye is not sufficient to control the number and position of the chemically sensitized nuclei, (ii)
i) Regarding the adsorption state of the dye, it is shown that the adsorption state in which the aggregate is more developed controls the chemical sensitization nucleus and the position.

Example-3 Using the octahedral AgBr emulsion prepared in Example 1, powder Dye3 was added to the emulsions A, B and C in an amount of 90% of the saturated adsorption amount, respectively. A at 40 ° C and B at 60 ° C. And C at 75 ℃
Aged for 20 minutes. A part of this emulsion is taken out and its reflection spectrum is measured. The results are shown in FIG. A →
In the order of B → C, the J-aggregates are formed, the peak wavelength is also increased, and the J-aggregates grow larger. This emulsion A, B, C
They were respectively _{55 ℃, Na 2 S 2 O} 3 · 5H 2 O aqueous solution 1.0 × 10 ^-5
Only mol / mol AgBr was added over 10 minutes, and after 5 minutes, 0.4 × 10 ⁻⁵ mol / mol AgBr of the above-mentioned gold sensitizer was added, followed by aging for 50 minutes. After aging, almost all the adsorbed dye was desorbed at pH 2.5 and pAg3.4, washed with water, redispersed, Dye4 was added at 38% of the saturated adsorption amount, and then the antifoggant TAI and coating aid were added. In addition, coating (the coated silver amount was 1.5 g / m ² ). The emulsion coating films of A, B, and C were subjected to a wet exposure for 1/1000 seconds through a filter which transmits light of 500 nm or more, and the MAA-1 developer solution
Develop for 10 minutes at 0 ° C. The sensitivities obtained from the obtained characteristic curves are shown in Table 2. The film of C, which was chemically sensitized in the state where the J aggregate was grown large, showed higher sensitivity.

Example-4 0.9 μm prepared by extending the crystal growth time of Example 1
φ octahedral AgBr emulsions D to J with Dye 1 40m each
was added in g / 150 ml emulsion (0.14 mol), then _{Na 2 S 2 O 3 · 5H} 2 O is aging 30 minutes at 55 ° C. and 1.0 × 10 ^-5 mol / mol AgBr the above gold sensitizer 0.4 × 10 ^-5 mol / mol AgBr only added, 50
Aged for minutes. After ripening, the emulsions of D to J were kept at 45 ° C. for 20 minutes under the conditions shown in Table 3, and then centrifuged and precipitated. The first settling supernatant liquid was taken out, and each pH was adjusted to 6 with NaOH.
4 and measured the spectral absorption spectrum of the solution,
The results shown in FIGS. 3 (a) and 3 (b) were obtained. At pH 6.4, all the dye remains adsorbed on the AgX particles, but at pH 4
In the following, most of the dye is desorbed. And, it is shown that the desorption is promoted more when the solution condition is set to low pAg.

Example-5 A sample was prepared by using the emulsion prepared in Example 1 above as the emulsion for the fourth layer of Example-1 Sample 104 of JP-A-62-215271 and processed in the same manner as in Example-1. After that, good photographic properties were exhibited.

 A preferred embodiment of the present invention is as follows.

1. The chemical sensitization method according to claim 1, wherein the AgX grains are the AgX grains described in I-1 to I-4.

2. The chemical sensitization method according to the claims, wherein the adsorbent is a compound selected from the antifoggants, stabilizers and sensitizing dyes described in II-1 and II-2.

3. The chemical sensitization method according to the claims, wherein the adsorbent is imidacyanin.

4. The chemical sensitization method according to claim 1, wherein the adsorbent is an antifoggant or stabilizer having a pKsp value of 10.5 or more.

5. The chemical sensitization method according to the claim, wherein the adsorption amount of the adsorbent is in a range of 50 to 100% of the saturated adsorption amount (a desensitization amount region referred to as a sensitizing dye).

6. The chemical sensitization method according to claim 1, wherein the adsorption of the adsorbent is performed at a temperature higher than the temperature at the next chemical ripening and for 7 minutes or more.

7. The chemical sensitization method according to claim 1, wherein the chemical sensitization is performed by adding a sulfur sensitizer and a gold sensitizer.

8. The chemical sensitization method according to claim 1, wherein the chemical sensitization is performed at a low temperature of 30 to 50 ° C.

9. The chemical sensitization method according to the claims, characterized in that the adsorbent is desorbed and then removed by washing with water.

10. Chemical sensitization according to claim 1, characterized in that the pH of the solution at the time of desorption / washing removal is (pKa + 0.5) to (pKa-3) using the pKa value of the adsorbent. Law.

11.The pH and pAg of the solution at the time of desorption / washing removal are pH 1.5-6.0, pAg
The chemical sensitization method according to claim 1, wherein the chemical sensitization method is 1.8 to 6.0.

12. Desorption and washing with water of the adsorbent is 10 ~ 1% of the adsorbent adsorbed.
Chemical sensitization method according to the claims, characterized in that it is 00%, preferably 25-100%, more preferably 50-100%.

13. The chemical sensitization method according to the claim, wherein the desorption and washing with water of the adsorbent are the desorption and washing with water up to the optimum addition amount point in terms of photographic properties.

14. The chemical sensitization method according to claim 1, wherein unreacted residual chemical sensitizer is removed by washing during or after the steps of desorbing and washing and removing the adsorbent.

15. In order to recover the reduction sensitization performance of the particle surface, which was lost due to the low pH treatment during desorption and washing with water, pH 6.5-
9. The chemical sensitization method according to claim 1, wherein the chemical sensitization is performed for 5 to 30 minutes.

16. The chemical sensitization method according to the claims, characterized in that after redispersion, the most suitable additives (sensitizing dye, antifoggant, stabilizer) from the viewpoint of photographic properties are added.

17. The sensitizing dye added after redispersion is a selective adsorption type described in II-2, and the formation position of the chemical sensitizing nucleus and the selective adsorption position of the sensitizing dye are different from each other. Sensitization method.

[Brief description of drawings]

FIG. 1 is a schematic view showing one form of typical AgX particles preferably used in the present invention. FIG. 2: Reflection spectra of emulsions A, B and C before chemical sensitization in Example 3. The horizontal axis represents the spectral wavelength, and the vertical axis represents the absorptance. 3 (a) and (b): Absorption spectra of desorbed dye in the first sedimentation supernatant of the emulsion of Example 4.

Claims (5)

[Claims] 1. A method for chemically sensitizing a silver halide emulsion, wherein the chemical sensitization is performed by [adsorbing an adsorbent on the surface of silver halide grains → adding a chemical sensitizer and chemically ripening → adsorbed adsorbent]. Desorption of the adsorbent is removed from the silver halide emulsion to remove 10 to 100% of the adsorbed adsorbent from the silver halide emulsion]. Chemical sensitization method of silver halide emulsion. 2. The adsorbent is a spectral sensitizing dye, an antifoggant,
2. The chemical sensitization method for silver halide emulsions according to claim 1, which is a stabilizer or a compound obtained by organically bonding them. 3. The pH value of the desorption is adjusted to the pH value of the adsorbent (pK
The chemical sensitization method according to claim (1), wherein the chemical sensitization is performed by setting a + 0.5) or less. Here, pKa represents the acid dissociation constant or the protonation constant of the sensitizing dye. 4. The adsorbent is a selective part adsorption type adsorbent, and the selective adsorptivity is [(number of adsorbed molecules in selective adsorption part / cm ² ) / (number of adsorbed molecules in non-selective adsorption part / cm ² )]. The method of chemical sensitization of a silver halide emulsion according to claim 1, wherein /≧2.5 and the adsorbent is an adsorbent selected by the method (a) below. (A) n kinds of emulsion coatings of single-seed emulsion particles are put into a dye solution in the same container, and the dye is adsorbed on the emulsion particles,
The coated material is taken out, the (dye adsorption amount / cm ² ) on the particles is determined, and it is selected by comparing the n kinds of particles. 5. The method of chemically sensitizing a silver halide emulsion according to claim 1, wherein the temperature at which the adsorbent is adsorbed is higher than the temperature at the chemical ripening.