JP2603168B2 - Method for producing silver halide photographic emulsion - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a silver halide photographic emulsion.

[0002]

BACKGROUND OF THE INVENTION For color, X-ray,
Silver iodobromide emulsions are used for light-sensitive materials for general black and white use, and chemical sensitization methods such as reduction sensitization, sulfur sensitization, and gold sensitization are performed.

[0003] High sensitivity can be obtained by using such chemical sensitization.

However, at the same time, the sensitivity to red light is increased only by chemical sensitization without performing spectral sensitization to red light, and fog is generated by red safelight. (See US Pat. No. 3,411,914, Japanese Patent Publication No. 45-8831, etc.).

That is, workability under a relatively bright red safelight is significantly impaired.
There is a high risk of unexpected fog due to safelights during handling by general consumers.

As a technique for eliminating such red safelight fog, for example, US Pat. No. 3,411,914,
JP-A-46-6073 discloses a method of adding a tetrazaindene during chemical sensitization or providing a dye filter layer.

However, this method has a disadvantage that the thermal stability of the photosensitive material is remarkably deteriorated and thermal fog frequently occurs.

Further, Japanese Patent Publication No. 45-8831 discloses a method of performing chemical sensitization with (I) a mercaptide.
This method has the disadvantage that the thermal stability is greatly deteriorated, and the sensitivity is reduced during long-time exposure at low illuminance and the low illuminance reciprocity failure characteristic is deteriorated.

Furthermore, Japanese Patent Publication No. 56-24937 discloses a method of chemical sensitization using a thiosuccinimide compound, but this method cannot provide sufficient sensitivity.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its main objects to reduce fog due to red safelight, to reduce heat fog increase, and to obtain low illuminance reciprocity failure characteristics. It is an object of the present invention to provide a method for producing a high-sensitivity silver halide emulsion with little deterioration of the emulsion.

[0011]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a monodisperse emulsion of silver halide grains, wherein silver ions and halide ions are supplied in the presence of a protective colloid to grow seed crystals. And the supply rate of halide ions are gradually increased with the growth of the grains.
A portion containing silver iodide at a concentration of 20 mol% or more inside
In the formation, the supply of iodine ions in the halide ion solution is terminated before the supply of silver ions is completed, and
After the addition of the halide solution containing iodide ions,
Supply a halide solution that does not contain ON, and when supplying iodide ions , adjust the ammonia content of the liquid phase to 0.3 N or more,
This is achieved by a method for producing a silver halide photographic emulsion having a pAg value lower than 8.

Hereinafter, the present invention will be described in detail.

The silver halide grains in the emulsion of the present invention are silver halides containing silver iodide, and may be any of silver iodochloride, silver iodobromide, and silver iodochlorobromide. It is preferable that silver iodobromide is used from the viewpoint that the following can be obtained.

The average silver iodide content in such silver halide grains is 0.5 mol% to 10 mol%, preferably 1 mol% to 8 mol%. This is because those in such a range have high sensitivity, little fog, and good developability and fixability.

[0015] Inside such silver halide grains,
There is a portion containing at least 20 mol% or more of a high concentration of silver iodide.

In this case, the inside of the particle is preferably located as far as possible inside from the outer surface of the particle, particularly preferably a portion separated from the outer surface by 0.1 μm or more.

The portion containing silver iodide at a high concentration may exist in a layered form or the whole core.
A more preferable result is obtained when the particle core is part or all of the particle except the shell having a thickness of 0.01 μm or more from the outer surface.

A more preferable result is obtained when the silver iodide concentration in the portion containing silver iodide at a high concentration is 30 mol% or more, particularly 30 mol% to 40 mol%.

The outside of the portion containing such a high concentration of silver iodide is covered with silver iodide-free silver halide.
It is covered. That is, in a preferred embodiment, from the outer surface
The shell portion having a thickness of 0.01 μm or more, particularly 0.01 to 1.5 μm, is formed of silver halide containing no silver iodide (usually silver bromide).

It is preferable that such silver halide grains have been subjected to chemical sensitization inside and / or on the surface of the grains.

Chemical sensitization includes, for example, sulfur sensitization using sodium thiosulfate, a thiourea compound, etc., gold sensitization using chloroaurate, gold trichloride, etc., thiourea dioxide, stannous chloride, silver ripening. Or reduction sensitization using electromagnetic radiation, other palladium sensitization, selenium sensitization, etc., and these can be used alone or in combination of two or more.

When reduction sensitization is performed on the inside or the surface of the grain and gold sensitization and sulfur sensitization are further performed on the grain surface,
Ru obtain a more favorable result.

The size of such silver halide grains is not particularly limited, but the average grain size is usually about 0.2 to 3 μm.

The emulsion of the present invention is a monodispersed emulsion of such silver halide grains.

That is, the size distribution of the silver halide grains dispersed in the protective colloid is narrow, and specifically, the coefficient of variation = ( standard deviation / average particle size ) is 20% or less. The average particle size may be determined by measuring 500 or more of one side or diameter of the particles using a micrograph or the like.

By using such a monodispersed emulsion, sensitization such as chemical sensitization can be sufficiently performed, and extremely high sensitivity can be obtained. Can be. At this time, red safelight fog does not occur, and thermal stability is extremely high.

In the Journal of the Photographic Society of Japan, Vol. 31, pp. 28-30, there is a report on an example in which iodide ions are localized inside grains in a silver iodobromide emulsion. However, none of the examples in this report has a silver iodide concentration profile as in the present invention, is a polydisperse emulsion having a wide grain size distribution, and has not been subjected to chemical sensitization. Therefore, the effect of the present invention is not realized in such an emulsion.

Further, Japanese Patent Application Laid-Open No. 57-179835 discloses that 0.5 to 10
A monodisperse emulsion having a pure silver bromide shell having a thickness of 0.01 μm or more on a core having a silver iodide concentration of mol% is described. However, it can not be said that the effect of the present invention is sufficient .

In order to produce such a silver halide emulsion, the following method is preferably employed.

Thus, a silver halide emulsion having excellent monodispersibility can be produced stably and quickly. That is,
In the presence of a protective colloid, from seed that is substantially free of twin supplies ammoniacal silver ions and halide ions
Grow crystals .

In this case, the supply rates of silver ions and halide ions increase gradually with the growth of silver halide grains.

In the stepwise increase, the feed rate is usually increased in proportion to the increase in the surface area of the silver halide grains.

Silver iodide at a concentration of 20 mol% or more
In order to form the portion to be contained, the ammonia concentration in the liquid phase is set to 0.
Halide ions containing iodine ions are supplied under an atmosphere of 3N or more and pAg lower than 8.

The supply of halide ions containing iodide ions is terminated before the end of supply of silver ions , and after the addition of the halide ion solution containing iodide ions , the supply of iodide ions is stopped. By supplying halide ions (usually only bromine ions) containing no ions, silver halide grains are grown.

In such a case, the seed crystal substantially containing no twin is 90% of the total number of the constituent particles.
The above-mentioned particles are so-called regular particles and have a regular octahedral, regular hexahedral or tetrahedral shape.

The seed crystal is preferably a monodisperse emulsion as described above. Further, it is preferably silver bromide or silver iodobromide, and particularly preferably silver iodobromide containing 40 mol% or less, more preferably 30 to 40 mol% of iodine.

Such a seed crystal may enter the growing step immediately after the seed crystal is formed, or may enter the growing step after desalting the seed crystal emulsion and adjusting the conditions again. .

The seed crystal used in the present invention is the seed crystal at the end of its growth.
Amount of silver corresponding to 1/250 to 1/3 of the amount of silver used before
Is used.

In such a case, the seed crystal may be subjected to reduction sensitization before its growth. As the reduction sensitization method used,
An organic reducing agent such as thiourea dioxide may be used, and reduction sensitization can also be achieved by a method of ripening at a low pAg or a method of exposure to electromagnetic radiation such as X-rays, γ-rays, and visible light. it can.

Using a seed crystal, a silver halide crystal is
The silver ion source of silver halide supplied in the growing step (hereinafter referred to as a seed crystal growing step) is an ammoniacal silver ion solution, and ammonia is added to a silver nitrate solution to form an ammine complex salt equivalent, Alternatively, it contains ammonia in an equivalent amount or more.

On the other hand, the halide ion source is a halide solution containing various halides, such as potassium bromide, potassium iodide, sodium chloride, alone or a mixture thereof.
Alternatively, it is an ammoniacal halide solution.

According to the present invention , 20
In order to form a portion having a silver iodide concentration of at least mol%, the halide solution added simultaneously with silver ions must contain iodine ions at least 20 mol % of the silver amount added at the same time. The part containing silver iodide at a concentration of 20 mol% or more
In the step of forming the fraction, it is necessary to previously set the ammonia ion concentration in the liquid phase to be charged to 0.3 N or more and to make the pAg lower than 8 at 40 ° C.

If the ammonia ion concentration is too low, or if the pAg is 8 or more, small grains are generated during the growth of silver halide grains, making it impossible to obtain a monodisperse emulsion.

Unlike the present invention, silver iodide is contained at a high concentration.
When part that is on the surface, the effect of the present invention can not be obtained, the sensitivity is low, becomes very accept easily red safelight fog. In order to obtain the effect of the present invention, silver iodide must be used at a high concentration.
Moiety containing preferably be in as much as possible inside the particles, follicle-free shell thickness high AgI mixed crystal is preferably at least 0.01 [mu] m.

Therefore, the halide solution containing iodide ions is preferably added at a relatively early stage of the seed crystal growth process . The part containing the silver iodide in high concentration
The concentration of iodide ions in the halide when forming
20 to 30 mol%.

The addition of the halide ion and ammoniacal silver ion solution to the emulsion containing crystal grains that grow by receiving silver halide with the seed crystal as a growth nucleus includes:
Although it may be performed alternately in time series, it is preferable to use the double jet method, and two or more jets can be used simultaneously.

The silver halide emulsion of the present invention can be doped with various metal salts or metal complex salts during or after the growth of the silver halide grains. For example,
Gold, platinum, palladium, iridium, rhodium, bis Ma <br/> scan, cadmium and copper or the like metal salts or metal complexes, and a combination of these applications.

[0048] Further, excess halogenated compounds produced during steel tone of the emulsions of the present invention, or by-product or nitrates has become unnecessary, salts such as ammonia, compounds such as may be removed. As these removal methods, a commonly used Nudel washing method, a dialysis method, a coagulation precipitation method, or the like can be appropriately used.

The emulsions of the present invention have very good properties when subjected to chemical sensitization.

Among the chemical sensitization methods, sulfur sensitization can be performed by using, for example, sodium thiosulfate, thiourea, allylthiourea, and the like. Gold sensitization is performed by using, for example, sodium chloroaurate, gold It can be performed by using potassium thiocyanate or the like. Also,
As the gold-sulfur sensitization, chemical sensitization can be performed by using at least one of the above sensitizers in combination. In such a case, it is preferable to further add ammonium thiocyanate or the like to perform chemical sensitization.

The silver halide photographic emulsion having been subjected to chemical sensitization, according to purposes, further sensitizing dyes and their addition are added various additives. In this case, for example, the techniques described in Research Disclosure Nos. 17643 and 18431 can be applied.

The type of silver halide photographic light-sensitive material to which the emulsion of the present invention can be applied is not limited, and color photographic paper, color negative film, color positive film, black-and-white film (eg, X-ray light-sensitive material, printing light-sensitive material, etc.) ), It is also useful when used for any photosensitive material such as a photographic photosensitive material of a diffusion transfer system.

As described above, according to the production method of the present invention, there is no occurrence of red safelight fog and monodispersion.
Sufficiently high sensitivity can be obtained by chemical sensitization because it is an emulsion.
And fog generation due to high temperature storage is extremely small. Further
According to the method of the present invention, a photographic emulsion comprising silver halide grains having a relatively large particle size and excellent in monodispersity requiring high sensitivity can be stably and rapidly produced.

[0054]

EXAMPLES Next, the present invention will be described in more detail by way of examples, but embodiments of the present invention are not limited to these examples. Example 1 An average particle size of 0.3 was obtained by a double jet method while controlling at 60 ° C., pAg = 8 and pH = 2.0.
A monodisperse cubic silver iodobromide emulsion containing 1.5 mol% of silver iodide was obtained. When an electron micrograph of this emulsion was observed, the incidence of twin grains was 1% or less.

After desalting it, a silver nitrate solution was added to add
C., pAg = 3, pH = 6 to perform silver ripening.

This emulsion was seeded as an emulsion containing silver equivalent to 50 g in terms of silver nitrate. This amount corresponds to 2% of the silver amount after growth.

8.4 l of 2.5% gelatin aqueous solution kept at 40 ° C.
The seed crystal emulsion was dissolved in the solution, and 0.2 N equivalent of aqueous ammonia was added. Further, the pH was adjusted to 9.0 using glacial acetic acid, and a 3.2 N aqueous ammonia silver ion solution and a halide aqueous solution were added according to the flow rate profile shown in FIG. 1A, followed by stirring and mixing.

As the aqueous halide solution, KB containing iodine ions corresponding to 2 mol % of the silver ions used is used.
A mixture of r and KI was used.

The pAg is kept constant at 9.0 and the pH is between 9 and 8.
The amount was changed in proportion to the amount of added ammoniacal silver ion. The obtained grains had silver iodide distributed throughout the grains, the average silver iodide content was 2 mol%, and the average grain size was 1.
The coefficient of variation was 21 μm and the coefficient of variation was 0.12.

The obtained emulsion was subjected to coagulation precipitation to remove excess water-soluble salts, and ammonium-thiocyanate, chloroauric acid and hypo were added to perform gold-sulfur sensitization.

Further, 4-hydroxy-6-methyl-1,3,3a, 7
-Add tetrazaindene, add general photographic additives such as spreading agents, thickeners, hardeners, etc.
It was applied and dried by a conventional method so as to have a concentration of 60 mg / 100 cm ^2, and a sample for sensitometry was obtained to obtain Comparative Sample 1-1.

On the other hand, in growing the seed emulsion,
Table 1 below shows the specified amount of ammonia to be added toStrange
e,Also, particle size0.5-0.8μm rangeTable 1 shows the silver iodide concentration of
To achieve the indicated concentration, And 0.8μmBeyondOuter surfaceTo
ReachSo that only AgBr exists in the range up to
Controls iodine ion concentration when adding iodideComparative sample except for
Like 1-1As a result, samples 1-2 to 1-5 were obtained.

[0063] Incidentally, pAg and pH upon addition high concentration iodide ion was shown in Table 1 below. Further, the flow rate at the time of adding a high concentration of iodide ions were 1/3 of Comparative Sample 1-1.

Each sample was subjected to gold-sulfur sensitization in the same manner as the comparative sample, and the same additives were added.

[Table 1] For sensitometric evaluation, exposure was performed for 1/100 second through an optical wedge using a light source having a color temperature of 5400 ° K. The exposure amount was 3.2 CMS.

Next, a developing treatment was carried out at 35 ° C. for 30 seconds using the following developing solution. <Developer> Potassium anhydride 50 g Hydroquinone 10 g Boric anhydride 1 g Potassium carbonate monohydrate 15 g 1-Phenyl-3-pyrazolidone 0.5 g Potassium hydroxide 4 g 5-Methyl-benzotriazole 0.005 g Potassium bromide 5 g Glutaraldehyde bisulfite 15 g Add 8 cc of glacial acetic acid to make 1 liter.

The sensitometric sample was left at 60 ° C. and 50% relative humidity for 3 days, and the increase in fog density was measured. (Oven test) Further, using a filter having the transmittance shown in FIG. 1B, red light was irradiated with incandescent light for 5 minutes, and the red light safelight fog density was measured.

Table 2 shows the results.

[Table 2] It can be seen that Samples 1-3 to 1-5 of the present invention exhibit higher sensitivity than Samples 1-1 and 1-2, and have a low rise in thermal fog and a low rise in red light fog. Comparative Example Each comparative sample was obtained in the same manner as in the sample 1-4 of the example.

In this case, in Sample 2-1, the end of the addition of iodine ions was matched with the end of the addition of silver ions (Sample 2).
-1).

As shown in Table 3, the preparation conditions were changed with reference to Samples 1-4, and Comparative Samples 2-2 to 2-2 were prepared.
-3 was obtained. In this case, only Samples 2-1 and 1-4 were monodisperse emulsions.

The same sensitometry, oven test and red fog test as in the example were performed.

The results are shown in the following table.

[Table 3]

[Table 4]

The silver halide photographic emulsion of the present invention and the photographic material using the same hardly cause red safelight fog. Further, since the emulsion is a monodisperse emulsion, a sufficiently high sensitivity can be obtained by chemical sensitization. And fog due to high temperature storage is extremely small.

Further, according to the production method of the present invention, it is possible to produce a photographic emulsion of silver halide grains having a relatively large grain size and excellent in monodispersity requiring high sensitivity stably and promptly. it can.

From the results shown in Table 4, the effect of the present invention is clear.

[Brief description of the drawings]

FIG. 1A is a graph showing a supply flow rate change profile of silver ions and halide ions during silver halide grain growth of each sample in an example. (B) It is a graph of the transmission spectrum distribution of the filter over the irradiation incandescent lamp light for evaluating red safelight fog in an Example.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-58-49938 (JP, A) JP-A-54-118823 (JP, A) JP-A-48-65925 (JP, A) JP-A-59-1983 177535 (JP, A) JP 2-59968 (JP, B2)

Claims (1)

(57) [Claims] When producing a monodisperse emulsion of silver halide grains, silver ions and halide ions are supplied in the presence of a protective colloid to grow seed crystals, and the supply rates of silver ions and halide ions are controlled by the grain size. , And more than 20 mol% inside the silver halide grains.
To form a portion containing silver iodide at a concentration of
The supply of iodide ions in the halide ion solution ended before the end supply of silver ions, and including iodide ion
After the addition of the halide solution is completed,
A method for producing a silver halide photographic emulsion, characterized in that, when an iodine ion is supplied, an ammonia content in a liquid phase is 0.3 N or more and a pAg is lower than 8 when an iodine ion is supplied.