JPH07152099A - Silver halide photographic emulsion, silver halide photographic sensitive material using the same emulsion, silver halide photographic sensitive material for medical use, and its processing method - Google Patents

Abstract

PURPOSE:To obtain a silver halide emulsion comprising platy silver halide particles, high in sensitivity and excellent in pressure characteristics, to obtain a silver halide photographic sensitive material, silver halide photographic sensitive material for medical use, and a processing method of the silver halide photographic sensitive material for medical use. CONSTITUTION:The silver halide photographic emulsion contains plate-like silver halide particles occupying >50% of the whole projection area of silver halide particles. In the plate-like particle, the distance L from the center P of the particle to the outer surface, distance L1 from P to the point A1 where the content of silver iodide is the max., and L2 from P to the point A2 where the content of silver iodide is min., are in the relation of L1<0.67L and L2>0.58L. Further, the content of silver iodide near the point A1 is not uniform but the content of silver iodide is substantially monotonously decreased from the point A1 to A2. The average content of silver iodide in the plate-like particle is <2mol%.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a tabular silver halide emulsion, a silver halide photographic light-sensitive material using the emulsion, particularly a medical silver halide photographic light-sensitive material, and a processing method for processing the light-sensitive material. It is a thing.

[0002]

2. Description of the Related Art Increasing the sensitivity of silver halide emulsions is the most effective means for improving various characteristics of photographic light-sensitive materials.
For example, recent high-sensitivity color photographic light-sensitive materials have been achieved by increasing the sensitivity of emulsion itself. It is widely known that the graininess can be improved by using a silver halide having a smaller grain size and a higher sensitivity as to the improvement of the image quality. Further, in the X-ray photographic light-sensitive material, in order to cut the crossover light to achieve high sharpness and maintain the sensitivity, it is essential to increase the sensitivity of the silver halide emulsion. For this reason, various researches and developments have been made in the art to increase the sensitivity of silver halide emulsions.

In particular, in recent years, many sensitization techniques using tabular silver halide grains have been disclosed, and examples thereof are JP-A Nos. 58-111935, 58-111936 and 58-111937.
No. 58-113927, No. 59-99433, etc.

These tabular silver halide grains are hexahedral,
Compared with so-called regular crystal silver halide grains such as octahedron, the surface area is large in the same volume, so it is possible to increase the adsorption amount of the sensitizing dye on the grain surface, and as a result, it is possible to achieve high sensitivity. There is.

Further, JP-A-63-92942 discloses a technique for providing a core having a high silver iodide content inside a tabular silver halide grain, and JP-A-63-151618 discloses a hexagonal tabular silver halide grain. Is disclosed, and the effect of increasing the sensitivity is shown.

In addition to this, Japanese Patent Laid-Open Nos. 63-106746 and 1
-183644 and JP-A-1-279237 disclose techniques relating to the composition distribution of tabular silver halide grains.

On the other hand, many techniques for improving the drawbacks of tabular silver halide grains have been disclosed. Tabular silver halide grains have the disadvantage of poor pressure characteristics. Here, the pressure characteristics mean two things: so-called pressure fog in which an unexposed portion is developed when a pressure is applied to a silver halide photographic light-sensitive material, and pressure desensitization in which sensitivity decreases during exposure. To do. If these characteristics are poor, they will cause serious defects as a silver halide photographic light-sensitive material. In general, silver halide grains are sensitive to pressure, and with increasing sensitivity, they become more sensitive to pressure, but in the case of tabular silver halide grains, the degree is It is remarkable. This means that when compared in the same volume, even if the materials have the same mechanical strength, the tabular grains are thinner than the spherical grains, so that a large moment is likely to be applied, and the mechanical strength of the grains as a whole is large. We interpret this as being weak.

The pressure characteristics differ depending on the silver halide shape, the halogen composition distribution in the silver halide grains, and the chemical sensitization conditions. Generally, when the degree of chemical sensitization is insufficient (chemical ripening is insufficient), pressure desensitization is poor, and when the degree of chemical sensitization is excessive, pressure desensitization is reduced but pressure fog is deteriorated.
The presence of a high iodine portion inside the silver halide grain improves the pressure fog but tends to increase the pressure desensitization.

For such deterioration of pressure characteristics, JP-A-59-99433, JP-A-60-35726, JP-A-60-147727, and JP-A-63-30
1937, 63-149641, 63-106746, 63-151618
No. 63-220238, JP-A No. 1-131541, and No. 2-193138.
No. 3, 3-172836, No. 3-231739 and the like, means for improving the pressure characteristics are disclosed, but the present inventors have found that these means do not achieve sufficient improvement effect. .

[0010]

An object of the present invention is to firstly provide a silver halide emulsion comprising tabular silver halide grains having high sensitivity and excellent pressure characteristics, and secondly, high sensitivity. And to provide a silver halide photographic light-sensitive material having excellent pressure characteristics. Thirdly, to provide a medical silver halide photographic light-sensitive material having high sensitivity and excellent pressure characteristics. A fourth object is to provide a method for processing a medical silver halide photographic light-sensitive material having high sensitivity and excellent pressure characteristics.

[0011]

The above object of the present invention can be achieved by the following constitutions.

1. 50% or more of the total projected area of the silver halide grains contained in the emulsion are tabular silver halide grains, and the distance P from the center P of the tabular grains to the outer surface L less than the distance L ₁ to the point a ₁ of halide content is the highest is 0.67 L, also the distance L ₂ of the silver iodide content from P to a point a ₂ as the lowest greater than 0.58L,
Furthermore, the silver iodide content in the vicinity of A ₁ is not uniform, and A ₁
The silver iodide content ranging A ₂ is substantially monotonously decreased from, and average silver iodide content of the tabular grains is 2 mol%
A silver halide photographic emulsion characterized by being less than.

2. In the tabular silver halide grain described in 1, the distance from the center P of the tabular silver halide grain to the side surface is L _b0 , and the distance L _b1 to the point B ₁ where the silver iodide content is the highest, The distance from the center P to the main plane is L _c0 , and the distance to the point C ₁ where the silver iodide content is highest is L.
_The silver halide photographic emulsion as described in 1 above, wherein when represented by _c1 , the following (I) is satisfied.

(L _b1 / L _b0 ) <(L _c1 / L _c0 ) ... (I) 3. Of the total projected area of silver halide grains contained in the emulsion
50% or more is a tabular silver halide grain having an average silver iodide content of less than 2 mol%, and when the tabular grain diameter is D, the radius from the center of the tabular silver halide grain is 0.05
A silver halide photographic emulsion containing 20% or less of total silver iodide in a grain within D and 70% or more of total silver iodide in a grain within a radius of 0.3 D from the center.

4. A silver halide photographic light-sensitive material containing the silver halide emulsion described in 1, 2, and / or 3.

5. A medical silver halide photographic light-sensitive material containing the silver halide emulsion described in 1, 2, and / or 3.

6. The medical silver halide photographic material as described in 5, wherein the medical silver halide photographic light-sensitive material is processed for a total processing time of 15 seconds to 90 seconds in a processing step including a processing bath containing no hardening agent. Method of processing photosensitive material.

The present invention will be described in more detail below.

In the silver halide emulsion of the present invention, silver iodobromide, silver iodochloride, silver chloroiodobromide and the like can be used as the silver halide, and particularly silver iodobromide and silver chloroiodobromide are usable. Is preferred. When silver iodobromide is used, the silver iodide content is preferably less than 2 mol% as the average silver iodide content in the entire silver halide grains. More preferably
It is 1.5 mol% or less. Most preferably, it is 1.0 mol% or less.

In the present invention, the "projected area of silver halide grains" is the "projected area" commonly used in the art.
Is used interchangeably with. (For example, James and Higgin
s, Fundamentals of Photographic Theory, Morgen and M
(Organ, New York, p. 15) The silver halide grains contained in the silver halide emulsion of the present invention are tabular silver halide grains in which 50% or more of the total projected area is tabular, and the effect of the present invention is sufficient if less than 50%. Can't get to. The tabular silver halide grain means a grain having two parallel main planes facing each other, and the tabular silver halide grain means an average value of the ratio of grain diameter to grain thickness (hereinafter referred to as average aspect ratio and (Named) is greater than 1.3. Here, the grain size means a projected area diameter (hereinafter referred to as grain size), which is a diameter corresponding to a circle of the projected area of the tabular silver halide grains (a diameter of a circle having the same projected area as the silver halide grains). ), And means the thickness of tabular silver halide grains 2
Shows the distance between two parallel principal planes.

The average aspect ratio of the tabular silver halide grains contained in the silver halide emulsion of the present invention (hereinafter sometimes abbreviated as tabular silver halide grains of the present invention) is preferably 2.0 or more and less than 20. Yes, but more preferably 2.0 or more
It is less than 8.0, most preferably 2.0 or more and less than 5.0. With very thin tabular silver halide grains having an average aspect ratio of 20 or more, the effect of improving the pressure resistance is not sufficient even if the silver iodide content has the distribution of the present invention. Further, in thick grains having an average aspect ratio of less than 2.0, the silver iodide content distribution of the present invention causes the sensitization to be insufficient.

The tabular silver halide grains of the present invention have an average silver iodide content of less than 2 mol%, preferably 1.5 mol% or less, more preferably 1.0 mol% or less. When the average silver iodide content is 2 mol% or more, desensitization is substantially observed, which is not practical.

In the present invention, the center of a tabular silver halide grain means that the silver halide grain is dispersed in a methacrylic resin in the same manner as the method described in the abstract of Inoue et al. Then, solidify it, make it into an ultra-thin section with a microtome, and pay attention to the section sample with the maximum cross-sectional area ~ 90% or more of the cross-sectional area, and draw the minimum circumscribed circle for the cross-section. It is the center of the circle.

In the present invention, the distance L from the center to the outer surface is defined as the distance between the center of the circle and the point intersecting the outer circumference of the particle when a straight line is drawn from the center of the circle to the outside. In addition, the method of detecting the points where the silver iodide content is the highest and the highest, and the points where the silver iodide content is the lowest, and the distances L ₁ and L ₂ from the center are measured by using a straight line drawn from the center of the circle to the outer circumference of It is determined by measuring the silver iodide content and position by the method.

When L, L ₁ and L ₂ defined on a straight line drawn in any direction from the center of the circumscribed circle satisfy the relational expression of the present invention, the present invention Of silver halide grains. Further, in the method for measuring the internal structure of a silver halide grain in the present invention, when there are a plurality of points having the highest silver iodide content, a point farther from the center is present, and when there are a plurality of points having the lowest silver iodide content. , The point near the center should be selected.

In the tabular silver halide grains of the present invention, the silver iodide content at the point where the silver iodide content becomes the highest (Ima
x) is preferably 5 to 40 mol%, more preferably 5 to 30 mol%. The silver iodide content (Imin) at the point where the silver iodide content becomes the minimum is preferably 0 to 5 mol%, and more preferably 0 to 2 mol%. Also, the difference (Im) between the highest silver iodide content (Imax) and the lowest silver iodide content (Imin)
ax-Imin) is preferably 2 to 40 mol%, 5 to 30
More preferably, it is mol%. The highest silver iodide content
When it exceeds 40 mol%, desensitization is observed, and when it is below 5 mol%, the effect of improving pressure resistance is lost. Further, when the minimum silver iodide content exceeds 5 mol%, desensitization becomes remarkable.

In the tabular silver halide grains of the present invention, the silver iodide content is not uniform in the vicinity of the point A ₁ where the silver iodide content becomes the highest. That is, the silver iodide content becomes maximum at the point A ₁ .

The point A ₁ where the silver iodide content is the highest is less than 0.67 L from the center, but is preferably 0.15 L or more and less than 0.67 L. Further, when the point A ₁ is not the center, the silver iodide content decreases once toward the inside, but may further increase again after reaching the minimum value inside thereof.

In the tabular silver halide grains of the present invention, the grain internal structure in which the silver iodide content is substantially monotonically decreased means a point A ₁ (distance L from the center where the silver iodide content is the highest). _{From 1} ) toward the point A ₂ (distance L ₂ from the center) where the silver iodide content is the lowest, (1) decreases linearly or (2) follows a curve having no maximum or minimum. It is a structure.

[0030] In the tabular silver halide grains of the present invention, it is preferable that (L ₂ -L ₁₎ is /L≧0.05, and more preferably further (L ₂ -L ₁₎ /L≧0.10.

If (L ₂ −L ₁ ) / L <0.05, the sensitization is insufficient. The silver iodide content from the point A ₂ where the silver iodide content is the lowest to the outermost surface of the grain can take any distribution of the silver iodide content from the highest content to the lowest content.

In the present invention, the distance L _b0 from the center to the side surface of the tabular silver halide grain is defined as 1/2 of the grain size, and the distance L _c0 from the center to the main plane is 1 of the grain thickness. /
Defined in 2. Further, regarding L _b1 and L _c1 , the above L
It can be obtained in the same manner as ₁ and L ₂ .

The silver halide emulsion of the present invention preferably satisfies the following (I): (L _b1 / L _b0 ) <(L _c1 / L _c0 ) ... (I) _Within the range of (II) below, the pressure is Little or no improvement in resistance.

(L _b1 / L _b0 )> (L _c1 / L _c0 ) ... (II) In the present invention, L _b1 / L _b0 and L _c1 / L _c0 are less than 0.67, preferably 0.15 or more and less than 0.67. Is.

In the present invention, 20% or less of total silver iodide in the grain is contained within a radius of 0.05D from the center of the tabular silver halide grain, and 70% of total silver iodide in the grain is contained within a radius of 0.3D from the center. %
It is characterized by containing the above, but it is preferable to contain 10% or less of the total silver iodide in the grain within a radius of 0.05D.
Also, within the radius of 0.3D from the center, 80% of the total silver iodide in the grain
It is preferable to contain the above, and it is preferable to contain 70% or more of the total silver iodide amount within the grain within a radius of 0.2 D, and further to contain 70% or more of the total silver iodide amount within the grain within a radius of 0.1 D. Preferably.

If the amount of silver iodide within a radius of 0.05 D is larger than 20% of the total silver iodide in the grain, the pressure resistance deteriorates and the radius of 0.3
Even if the amount of silver iodide within D is less than 70% of the total silver iodide in the grain, the pressure resistance deteriorates.

In the present invention, the amount of silver iodide having a radius of 0.3 D or less includes the amount of silver iodide having a radius of 0.05 D or less.

In the tabular silver halide grain of the present invention, the silver iodide content on the outermost surface of the grain is preferably 0 to 5 mol%, more preferably 0 to 2 mol%, and particularly 0 mol%. Is preferred.

Further, potassium iodide, silver iodide or the like is added to the silver halide emulsion of the present invention at the time of chemical sensitization or color sensitization or before or after the chemical sensitization to deposit iodine on the grain surface. Is also preferably used.

The silver iodide content on the outermost surface of silver halide grains contained in the silver halide photographic emulsion can be measured by X-ray photoelectron spectroscopy.

In the present invention, the silver iodide content and the average silver iodide content of each silver halide grain are determined by the EPMA method (Electr.
on Probe Micro Analyzer method). According to this method, a sample in which emulsion grains are well dispersed so as not to come into contact with each other is prepared, and an X-ray analysis by electron beam excitation and electron beam excitation is performed. By this method, the silver halide composition of each grain can be determined by obtaining the characteristic X-ray intensity of silver and iodide emitted from each grain. If the silver iodide content of at least 50 grains is determined by the EPMA method, the average silver iodide content can be determined from the average thereof.

The tabular silver halide grains of the present invention preferably have a more uniform iodide content between grains.
When the distribution of the iodide content between grains is measured by the EPMA method, the relative standard deviation is preferably 35% or less, more preferably 20% or less.

The average grain size of the tabular silver halide grains of the present invention is preferably 0.4 to 3.0 μm, more preferably 0.4 to 2.0 μm.

The average thickness of the tabular silver halide grains of the present invention is preferably 0.05 to 1.0 μm, more preferably 0.05 to 0.40 μm, still more preferably 0.05 to 0.30 μm.

The grain size and grain thickness can be optimized to optimize sensitivity, pressure characteristics and the like. Optimum particle size, optimum particle depending on other factors (sensitivity of hydrophilic colloid layer, hardening degree, chemical ripening condition, set sensitivity of photosensitive material, amount of silver, etc.) of photosensitive material that affect sensitivity and pressure characteristics. Have different thickness.

The tabular silver halide grain of the present invention is preferably a monodisperse emulsion having a narrow grain size distribution, specifically, (standard deviation of grain size / average grain size) × 100 = broadness of grain size distribution (% When the breadth of distribution is defined by), it is preferably 25% or less, more preferably 20% or less, and particularly preferably 15% or less.

The tabular silver halide grains of the present invention preferably have a small thickness distribution. Specifically, when the width of the distribution is defined by (standard deviation of thickness / average thickness) x 100 = width of thickness distribution (%), it is preferably 25% or less, more preferably 20%. It is as follows, and particularly preferably 15% or less.

The tabular silver halide grains of the present invention are crystallographically classified as twins. Twins are silver halide crystals that have one or more twin planes within one grain. The twin morphology is classified by Klein and Moiser in the article Photographishe Korresponts.
respondenz) Volume 99, page 99, volume 100, page 57.

The tabular silver halide grain of the present invention has two or more twin planes parallel to the main plane. The twin plane can be observed with a transmission electron microscope. The specific method is as follows. First, a photosensitive silver halide emulsion is coated so that the main planes of the tabular silver halide grains contained are oriented substantially parallel to the support, and a sample is prepared. It is cut with a diamond cutter to a thickness of 0.1.
Obtain a thin section of about μ. The presence of twin planes can be confirmed by observing this section with a transmission electron microscope.

In the present invention, the average value of the distance between twin planes is preferably 0.008 μ or more, more preferably
It is 0.010μ or more and 0.05μ or less.

Here, the twin plane distance means the distance between twin planes when there are two twin planes, and the distance between twin planes among the twin planes when there are three or more twin planes. The longest distance.

In the present invention, the average value of the distance between twin planes can be obtained as follows. That is, by observing the section using the transmission electron microscope, arbitrarily select 100 or more tabular silver halide grains showing a cross section cut substantially perpendicular to the main plane, and twin for each grain. The face-to-face distance can be measured and the average can be obtained.

In the present invention, in the tabular silver halide grains, the outer wall of the crystal may be substantially composed of {111} faces or {100} faces. Further, it may have both a {111} plane and a {100} plane. In this case, 50% or more of the grain surface is a {111} plane, more preferably 60% to 90% is a {111} plane,
Particularly preferably, 70 to 95% is the {111} plane. It is preferable that the planes other than the {111} plane are mainly the {100} plane.
This plane ratio is {111} plane and {10} in adsorption of sensitizing dye.
The difference in adsorption dependence with the 0} plane was used [T. Tani, J. Imag
ing Sci., 29, 165 (1985)].

In the present invention, the tabular silver halide grains are preferably hexagonal. A hexagonal tabular grain (hereinafter sometimes referred to as a hexagonal tabular grain) has a hexagonal main plane ((111) plane) and a maximum side ratio of 1.0 to 2.0. Say that. Here, the maximum side ratio is the ratio of the length of the side having the maximum length to the length of the side having the minimum length forming a hexagon. In the present invention, it is also preferable that the hexagonal tabular grains have rounded corners if the maximum side ratio is 1.0 to 2.0. When the corner is rounded, the length of the side is represented by the distance between the straight line portion of the side and the intersection with the line obtained by extending the straight line portion of the adjacent side. Further, it is also preferable that the tabular grains are more rounded and have a substantially circular shape.

In the present invention, it is preferable that each side forming the hexagon of the hexagonal tabular grain has at least ½ thereof substantially a straight line. In the present invention, the side ratio is more preferably 1.0 to 1.5.

The silver halide emulsion of the present invention is preferably grown by a method of precipitating silver halide on seed grains.

For example, in a method for producing a silver halide photographic emulsion, which is carried out by supplying a water-soluble silver salt solution and a water-soluble halide solution to the presence of a protective colloid to obtain the tabular silver halide emulsion of the present invention. , (A) Silver iodide content of 0
A core particle forming step of maintaining pBr of the mother liquor at 2.5 to -0.7 for a period of ½ or more from the initial stage of forming a silver halide precipitate of 5 mol% is provided, and (b) following the core particle forming step, Providing a seed grain forming step of forming a silver halide seed grain which is substantially monodisperse spherical twin crystals by containing 10 ^{−5 to} 2.0 mol of a silver halide solvent per mol of silver halide, or
Subsequent to the core particle forming step, a seed particle forming step of forming a silver halide twin seed particle by raising the temperature of the mother liquor to 40 to 80 ° C. is provided, and (c) Next, a water-soluble silver salt solution is added. A method of adding a water-soluble halide solution and / or silver halide fine grains and providing a growth step of growing seed grains is preferably used. Here, the mother liquor is a liquid (including a silver halide emulsion) that is used in the preparation stage of a silver halide emulsion up to a completed photographic emulsion.

The silver halide grains formed in the nucleus grain forming step are twin grains composed of 0 to 5 mol% silver iodide.

A water-soluble silver salt may be added for the purpose of controlling ripening during the seed grain forming step.

The seed grain growing step for growing the silver halide seed grains includes pAg, pH, temperature, silver halide solvent concentration and silver halide composition, silver salt and halogen during silver halide precipitation and Ostwald ripening. This is achieved by controlling the addition rate of the chloride solution.

In order to obtain the silver halide photographic emulsion of the present invention, it is preferable to change pAg, pH and the like during the seed grain growing step. Also, the so-called conversion method can be advantageously used.

In preparing the emulsion of the present invention, a known silver halide solvent such as ammonia, thioether or thiourea can be present during the seed grain forming step and the seed grain growth.

To obtain the tabular silver halide grains of the present invention, the conditions for growing the produced seed grains are as follows: JP-A-51-39027, JP-A-55-142329, JP-A-58-113928, and JP-A-58-113928. 54
-48521 and 58-49938, the water-soluble silver salt solution and the water-soluble halide solution were added by the double jet method, and the nucleation did not occur depending on the growth rate of the particles. , And the rate at which the size distribution does not spread due to Ostwald ripening, that is, the rate at which new nuclei occur
There is a method of gradually changing it in the range of 100%. Further, as another condition for growing seed grains, a method of growing by adding silver halide fine particles, dissolving and recrystallizing is preferably used, as shown in section 88 of the 1983 Annual Meeting of the Photographic Society of Japan. To be Particularly, silver iodide fine particles, silver bromide fine particles, and silver iodobromide fine particles are preferably used.

In the production of the silver halide emulsion of the present invention, the stirring conditions during production are extremely important. As the stirring device, the device disclosed in JP-A-62-160128, in which the additive liquid nozzle is installed in the liquid near the mother liquid inlet of the stirrer, is particularly preferably used. At this time, the stirring rotation speed is 100 to 1
It is preferably 200 rpm.

The details regarding the above-mentioned supersaturation factor are as follows.
For example, the description in JP-A-63-92942 or JP-A-1-213637 can be referred to.

The silver halide grains contained in the silver halide emulsion of the present invention include a cadmium salt, a zinc salt, a lead salt, a thallium salt and an iridium salt (including a complex salt) in the process of forming and / or growing the grains. ), A rhodium salt (including a complex salt), and an iron salt (including a complex salt), at least one metal ion is added to allow the metal element to be contained inside and / or on the surface of the particle. it can.

In the present invention, it is preferable to use gelatin as the dispersion medium for the protective colloid of silver halide grains. Examples of the gelatin include alkali-processed gelatin, acid-processed gelatin and low molecular weight gelatin (molecular weight of 20,000 to 10).
10,000), modified gelatin such as phthalated gelatin is used. Other hydrophilic colloids can also be used. Specifically, Research Disclosure (Research D
isclosure, hereinafter abbreviated as RD. ) Volume 176 NO.17643 (1978
The items described in Section IX of December) are listed.

The silver halide emulsion of the present invention may remove unnecessary soluble salts during the growth of silver halide grains,
Alternatively, it may remain contained. The removal of the salts can be carried out according to the method described in IX of RD Vol. 176, No. 17643.

In the present invention, the silver halide photographic emulsion can be chemically sensitized. There are no particular restrictions on the conditions of the chemical ripening, that is, the steps of chemical sensitization, such as pH, pAg, temperature, time, etc., and the conditions generally used in the art can be used. For chemical sensitization, a sulfur sensitization method using a compound containing sulfur capable of reacting with silver ions or active gelatin, a selenium sensitization method using a selenium compound, a tellurium sensitization method using a tellurium compound, or a reducing substance is used. The reduction sensitization method to be used, gold and other noble metal sensitization methods using a noble metal can be used alone or in combination.
A selenium sensitization method, a tellurium sensitization method, a reduction sensitization method and the like are preferably used.

In the case of selenium sensitization, the selenium sensitizer used comprises a wide variety of selenium compounds. For example, in this regard, U.S. Pat.Nos. 1,574,944, 1,602,592, 1,62.
3,499, JP 60-150046, JP 4-25832, 4-1
09240, 4-147250, etc. Useful selenium sensitizers include colloidal selenium metal, isoselenocyanates (eg, allyl isoselenocyanate, etc.), selenoureas (eg, N, N-dimethylselenourea, N, N, N′-triethylselenoate). Urea, N, N, N'-trimethyl
-N'-heptafluoroselenourea, N, N, N'-trimethyl-N '
-Heptafluoropropylcarbonyl selenourea, N, N,
N'-trimethyl-N'-4-nitrophenylcarbonyl selenoureas, etc.), selenoketones (eg, selenoacetone,
Selenoacetophenone, etc.), selenoamides (eg,
Selenoacetamide, N, N-dimethylselenobenzamide, etc.), selenocarboxylic acids and selenoesters (eg, 2-selenopropionic acid, methyl-3-selenobutylate, etc.), selenophosphates (eg, tri-p- Triselenophosphate, etc.) and selenides (diethylselenide, diethyldiselenide, etc.).
Particularly preferred selenium sensitizers are selenoureas, selenoamides, and selenium ketones.

Specific examples of techniques for using these selenium sensitizers are disclosed in the following patents. U.S. Pat.No. 1,574,944
No. 1, No. 1,602,592, No. 1,623,499, No. 3,297,446
Issue 3,297,447, 3,320,069, 3,408,196,
3,408,197, 3,442,653, 3,420,670, 3,5
91,385, French Patents 2,693,038, 2,093,209
No. 52-34491, 52-34492, 53-295, 53-295
57-22090, JP-A-59-180536, 59-185330, 59
-181337, 59-187338, 59-192241, 60-1500
46, 60-151637, 61-246738, JP 3-4221
No. 3, No. 3-24537, No. 3-111838, No. 3-116132, No. 3-1
48648, 3-237450, 4-16838, 4-25832,
4-32831, 4-96059, 4-109240, 4-140738
No. 4-140739, 4-147250, 4-149437, 4-
184331, 4-190225, 4-191729, 4-195035
No., British Patent Nos. 255846 and 861984. HE Spence
r et al., Journal of Photographic Science, 31 volumes, 158-
It is also disclosed in scientific literature such as p. 169 (1983).

The amount of the selenium sensitizer used varies depending on the selenium compound used, silver halide grains, chemical ripening conditions and the like, but generally about 10 ^-8 to 10 ^-4 mol per mol of silver halide is used. The addition method is, depending on the properties of the selenium compound to be used, a method in which water or an organic solvent such as methanol or ethanol is dissolved alone or in a mixed solvent, or a method in which the solution is added in advance by mixing with a gelatin solution. However, the method disclosed in JP-A-4-140739, that is, the method of adding in the form of an emulsion dispersion of a mixed solution with a polymer soluble in an organic solvent may be used.

The temperature of the chemical ripening using the selenium sensitizer is
The range of 40 to 90 ° C is preferable. More preferably 45 ° C or higher
It is below 80 ℃. The pH is preferably in the range of 4 to 9 and the pAg is preferably in the range of 6 to 9.5.

Regarding the tellurium sensitizer and the sensitizing method, US Pat. Nos. 1,623,499, 3,320,069 and 3,772,031,
No. 3,531,289, No. 3,655,394, British Patent No. 235,211
Issue 1,121,496, Issue 1,295,462, Issue 1,396,696,
Canadian Patent No. 800,958, JP-A-4-204640, and JP-A-4-333
No. 043 and the like. Examples of useful tellurium sensitizers include telluroureas (e.g., N, N-dimethyl tellurourea, tetramethyl tellurourea, N-carboxyethyl-N,
N'-dimethyl tellurourea, N, N'-dimethyl-N'-phenyl tellurourea, phosphine tellurides (eg, tributylphosphine telluride, tricyclohexylphosphine telluride, triisopropylphosphine telluride, butyl-diisopropylphosphine) Telluride, dibutylphenylphosphine telluride), telluramides (eg,
Telluroacetamide, N, N-dimethyl tellurobenzamide), telluroketones, telluroesters, isotelloocyanates and the like. The technique for using the tellurium sensitizer is in accordance with the technique for using the selenium sensitizer.

It is also preferable to carry out so-called reduction sensitization by providing reduction sensitizing nuclei inside the grain and / or on the grain surface by placing in a suitable reducing atmosphere.

Preferred examples of the reducing agent include thiourea dioxide and ascorbic acid and their derivatives. Other preferred reducing agents include hydrazine, polyamines such as diethylenetriamine, dimethylamineboranes, sulfites and the like.

It is also preferable to carry out so-called reduction sensitization by providing reduction sensitizing nuclei inside the grain and / or on the surface of the grain by placing in a suitable reducing atmosphere.

Preferred examples of the reducing agent include thiourea dioxide and ascorbic acid and their derivatives. Other preferred reducing agents include hydrazine, polyamines such as diethylenetriamine, dimethylamineboranes, sulfites and the like.

The amount of the reducing agent added depends on the type of reduction sensitizer, the grain size of the silver halide grains, the composition and crystal habit, the temperature of the reaction system,
Although it is preferable to change the pH depending on the environmental conditions such as pH and pAg, for example, in the case of thiourea dioxide, as a rough guide, use of about 0.01 to 2 mg per mol of silver halide gives favorable results. In the case of ascorbic acid, a range of about 50 mg to 2 g is preferable per mol of silver halide.

As conditions for reduction sensitization, the temperature is about 40 to 70.
C, time about 10-200 minutes, pH about 5-11, pAg about 1-1
A range of 0 is preferred (where the pAg value is the reciprocal of the Ag ⁺ ion concentration).

The water-soluble silver salt is preferably silver nitrate.
By adding a water-soluble silver salt, so-called silver ripening, which is a kind of reduction sensitization technique, is performed. The pAg during silver ripening is suitably 1-6, preferably 2-4. The conditions such as temperature, pH and time are preferably within the above-mentioned reduction sensitization condition range. As a stabilizer of a silver halide photographic emulsion containing reduction-sensitized silver halide grains, a general stabilizer described below can be used, but it is disclosed in JP-A-57-82831. Antioxidants and / or papers by VS Gahler [Zeitshrift fur wissenschaftliche Photographie B
d.63, 133 (1969)] and the thiosulfonic acids described in JP-A No. 54-1019 are often used together with good results. The addition of these compounds may be carried out at any stage of the emulsion production process from crystal growth to the preparation process immediately before coating.

In the present invention, selenium sensitization, tellurium sensitization, reduction sensitization and the like may be used in combination, and it is preferable to use it in combination with another sensitization method, for example, a noble metal sensitization method.

The silver halide photographic light-sensitive material of the present invention is a silver halide photographic light-sensitive material containing the above-described silver halide emulsion of the present invention. For example, a black-and-white silver halide photographic light-sensitive material (for example, medical halogen) Silver halide photographic light-sensitive material, silver halide photographic light-sensitive material for printing, negative silver halide photographic light-sensitive material for general photography, etc., silver halide color photographic light-sensitive material (for example, silver halide color negative photographic light-sensitive material,
Silver halide color reversal photographic light-sensitive materials, silver halide color print photographic light-sensitive materials, etc.), diffusion transfer light-sensitive materials, heat-developable light-sensitive materials, etc., but black and white silver halide photographic light-sensitive materials are particularly preferable. Is a silver halide photographic light-sensitive material for medical use.

Further, the method of processing a medical silver halide photographic light-sensitive material of the present invention is a method of processing a silver halide photographic light-sensitive material containing the silver halide photographic emulsion of the present invention with a processing bath containing no hardener. Total process time from 15 seconds to 90 seconds
This is a processing method of processing in seconds.

In the present invention, it is also preferable to add a silver halide emulsion before the desalting step in order to accelerate the developing rate. For example, a thiocyanate compound (potassium thiocyanate, sodium thiocyanate, ammonium thiocyanate, etc.) is preferably added in an amount of 1 × 10 ^{−3 to} 3 × 10 ⁻² mol per mol of silver.

When a silver halide photographic light-sensitive material is formed using the silver halide emulsion of the present invention, the silver halide emulsion is chemically sensitized and various additives are added according to the purpose. . Examples of additives and the like used include Research Disclosure (RD) No. 17643 (1978).
December), No.18716 (November 1979) and No.308119
(December 1989). The places where they are written are listed below.

Additives RD-17643 RD-18716 RD-308119 Page Classification Page Classification Page Classification Chemical sensitizer 23 III 648 Upper right 996 III Sensitizing dye 23 IV 648-649 996-8 IV Desensitizing dye 23 IV 998 IV Dye 25 to 26 VIII 649 to 650 1003 VIII Development accelerator 29 XXI 648 Upper right fog inhibitor / stabilizer 24 IV 649 Upper right 1006 to 7 VI Whitening agent 24 V 998 V Hardener 26 X 651 Left 1004 to 5 X Surfactant Agent 26-7 XI 650 Right 1005-6 XI Antistatic agent 27 XII 650 Right 1006-7 XIII Plasticizer 27 XII 650 Right 1006 XII Sliding agent 27 XII Matting agent 28 XVI 650 Right 1008-9 XVI Binder 26 XXII 1003-4 IX Support 28 XVII 1009 XVII When the present invention is applied to medical X-ray radiography,
For example, a fluorescent intensifying screen containing a phosphor as a main component which emits near-ultraviolet light or visible light by exposure to penetrating radiation is used. It is desirable that the emulsion is adhered to both sides of a light-sensitive material prepared by coating the emulsion of the present invention on both sides and exposed.

The penetrating radiation as used herein is an electromagnetic wave of high energy and means X-rays and gamma rays.

The fluorescent intensifying screen means, for example, an intensifying screen mainly containing calcium tungstate as a fluorescent component or a fluorescent intensifying screen mainly containing a rare earth compound activated by terbium. As the fluorescent intensifying screen, a fluorescent component uniformly coated on a support or a cylindrical or conical coating can be used. German Karm an Karlsruhe presented at Session 868C of the '92 RSNA (Radiological Society of America) when using particularly low-sensitivity light-sensitive materials.
Like the nuclear reserch microstructure intensifying screen, by increasing the thickness of the fluorescent component and applying it in a conical shape, the sensitivity of the intensifying screen is increased and at the same time the quantum mottle is reduced to improve graininess. Is preferably used.

[0090]

The present invention will be described in detail below with reference to examples, but the embodiments of the present invention are not limited thereto.

Example 1 (Preparation of seed emulsion-1) Seed emulsion-1 was prepared as follows.

A1 ossein gelatin 24.2 g water 9657 ml polypropyleneoxy-polyethyleneoxy-disuccinate sodium salt (10% ethanol aqueous solution) 6.78 ml potassium bromide 10.8 g 10% nitric acid 114 ml B1 2.5N silver nitrate aqueous solution 2825 ml C1 potassium bromide 824 g Potassium iodide 23.5g Make up to 2825ml with water.

D1 1.75N Potassium bromide aqueous solution Solution B1 and solution C1 were each added to solution A1 using the mixing stirrer shown in JP-B Nos. 58-58288 and 58-58289 at the following silver potential control amount of 42 ° C.
Nucleation was performed by adding 464.3 ml by the double-sided mixing method over 1.5 minutes.

After the addition of the solutions B1 and C1 was stopped, it took 60 minutes to raise the temperature of the solution A1 to 60 ° C., adjust the pH to 5.0 with 3% KOH, and then add the solution B1 again. Solution C1 was added by the double jet method at a flow rate of 55.4 ml / min each for 42 minutes. The silver potential (measured with a silver ion selective electrode using a saturated silver-silver chloride electrode as a reference electrode) during this temperature increase from 42 ° C. to 60 ° C. and re-simultaneous mixing with the solutions B1 and C1 was +8 mv using the solution D1. And +16 mv.

After the addition was completed, the pH was adjusted to 6 with 3% KOH, and desalting and washing with water were immediately performed. In this seed emulsion, 90% or more of the total projected area of silver halide grains has a maximum side ratio of 1.0 to 2.0.
The average thickness of hexagonal tabular grains is 0.
It was confirmed with an electron microscope that the particle size was 06 μm and the average particle size (converted to a circle diameter) was 0.59 μm. The variation coefficient of thickness was 40% and the variation coefficient of distance between twin planes was 42%.

Preparation of Em-1 Tabular silver halide emulsion Em-1 having an average silver iodide content of 1.5 mol% was prepared using seed emulsion-1 and the following four kinds of solutions.

A2 ossein gelatin 34.03 g polypropyleneoxy-polyethyleneoxy-disuccinate sodium salt (10% aqueous ethanol solution) 2.25 ml seed emulsion-1 1.218 mol equivalent Make up to 3150 ml with water.

B2 1721 g potassium bromide Make up to 3616 ml with water.

C2 Silver nitrate 2457 g Water is made up to 4133 ml.

D2 3 wt% gelatin and silver iodide grains (average grain size: 0.05 μ) Fine grain emulsion (*) Equivalent to 0.211 mol * Into 6.64 liter of 5.0 wt% gelatin aqueous solution containing 0.06 mol potassium iodide , 7.06 mol of silver nitrate and 2 liters of an aqueous solution each containing 7.06 mol of potassium iodide were added over 10 minutes. The pH during the formation of the fine particles is 2.
The temperature was controlled at 0 and the temperature at 40 ° C. After particle formation, the pH was adjusted to 6.0 using an aqueous sodium carbonate solution.

Solution A2 was vigorously stirred in the reaction vessel while maintaining the temperature at 60 ° C., and part of solution B2, part of solution C2 and solution D2 were added thereto by the simultaneous mixing method over 44 minutes, After that, the remaining amounts of the solution B2 and the solution C2 were successively added over 27 minutes by the simultaneous mixing method. During this time, pH was 5.8 and pA
g kept at 9.0 from beginning to end. Here, the addition rates of the solution B2 and the solution C2 were changed in a function-like manner with respect to time so as to be commensurate with the critical growth rate. That is, the addition was performed at an appropriate addition rate so that small particles were not generated other than the growing seed particles and polydispersion did not occur due to Ostwald ripening. The addition rate of the solution D2 is 0.11 with the rate ratio (molar ratio) with the solution C2.
Kept at.

After the completion of the addition, this emulsion was cooled to 40 ° C., and a 13.8% (weight) aqueous solution of modified gelatin modified with a phenylcarbamoyl group (a substitution rate of 90%) as an aggregating polymer agent 1800
ml was added and stirred for 3 minutes. Then, a 56% (weight) acetic acid aqueous solution was added to adjust the pH of the emulsion to 4.6, the mixture was stirred for 3 minutes, allowed to stand for 20 minutes, and the supernatant was drained by decantation. Then, 9.0 l of distilled water at 40 ° C was added, and the supernatant was drained after standing with stirring, 11.25 l of distilled water was further added, and after standing with stirring, the supernatant was drained. Subsequently, a gelatin aqueous solution and a 10% (weight) aqueous sodium carbonate solution were added to adjust the pH to 5.80, and the mixture was stirred at 50 ° C. for 30 minutes and redispersed. After re-dispersion at 40 ℃ pH 5.80, pAg 8.
Adjusted to 06.

When the obtained silver halide emulsion was observed with an electron microscope, tabular silver halide grains having an average grain size of 0.98μ, an average thickness of 0.22μ, an average aspect ratio of about 4.5 and a grain size distribution of 18.9% were obtained. Met. Also, the average distance between twin planes is
0.018μ, 97% (number) of all tabular silver halide grains with a twin plane distance to thickness ratio of 5 or more, 49% with 10 or more grains, and 17% with 15 or more grains. Was occupied.

Further, as a result of obtaining the distribution of the silver iodide content in the grain, when the distance from the center to the outer surface is L, the distance from the center to the point A ₁ where the silver iodide content is the highest. L ₁ was 0.42 L, and the distance L ₂ to the point A ₂ where the silver iodide content was the lowest was 0.62 L. However, from the distance of 0.42 L to the distance of 0.58 L toward the outer surface, the uniform layer showed the highest silver iodide content.

Preparation of Em-2 With respect to the preparation of Em-1, the addition time of the solution D2 was 5 l, and the ratio (molar ratio) of the addition rate of the solution D2 to the addition rate of the solution C2 is shown in Table 1. To the particle size,
Further, the addition rates of the solutions B2 and C2 are changed in a function-like manner with respect to time so as to be commensurate with the critical growth rate, that is, small particles are not generated except for the growing seed particles, and polydispersion is performed by Ostwald ripening. Em-2 was prepared in the same manner as Em-1 except that it was added at an appropriate addition rate so as not to turn into a solid.

When the obtained silver halide emulsion was observed with an electron microscope, tabular silver halide grains having an average grain size of 0.98μ, an average thickness of 0.22μ, an average aspect ratio of about 4.5 and a grain size distribution of 17.9% were obtained. Met. The average distance between twin planes is 0.
018μ, 97% (number) of all tabular silver halide grains have a twin-to-plane distance to thickness ratio of 5 or more, 49% of 10 or more grains and 17% of 15 or more grains. Had occupied.

Further, as a result of obtaining the distribution of the silver iodide content in the grain, when the distance from the center to the outer surface is L, the distance from the center to the point A ₁ where the silver iodide content is the highest. L ₁ is
It was 0.42 L, and the distance L ₂ to the point A ₂ where the silver iodide content was the lowest was 0.70 L. The silver iodide content showed a monotonous decrease from the distance of 0.42 L to the distance of 0.70 L toward the outer surface.

[0108]

[Table 1]

Preparation of Em-3 In Em-1, the amount of potassium bromide and the amount of finishing of solution B2 and the amount of solution D2 used were changed to B2, C2 and D2.
The tabular silver halide emulsion Em-3 having an average silver iodide content of 1.0 mol% was prepared by changing the addition rate of. However, D2
The addition rate of was constant at a molar ratio with respect to C2, similar to Em-1.

When the obtained emulsion was observed with an electron microscope, it was found to be tabular silver halide grains having an average grain size of 0.98 μm, an average thickness of 0.21 μ, an average aspect ratio of 4.6 and a grain size distribution of 18%.

Preparation of Em-4 In Em-2, the amounts of potassium bromide and the finishing amount of the solution B2 and the amount of the solution D2 used were changed to prepare B2, C2 and D2.
Was changed to prepare a tabular silver halide emulsion Em-4 having an average silver iodide content of 1.0 mol%. Further, the addition rate of D2 was decreased in a molar ratio with respect to C2 as the particle size was increased, similar to Em-2.

When the obtained emulsion was observed with an electron microscope, it was found to be tabular silver halide grains having an average grain size of 0.98 μm, an average thickness of 0.21 μ, an average aspect ratio of 4.6, and a grain size distribution of 17.5%.

Preparation of Em-5 and 6 Further, tabular silver halide emulsions Em-5 and Em-6 having an average silver iodide content of 0.5 mol% were prepared in the same manner.

A list of emulsions is shown in Table 2 below.

[0115]

[Table 2]

Subsequently, optimum amounts of the following methanol solutions of spectral sensitizing dyes A and B were added to these emulsions, and after spectral sensitization, ammonium thiocyanate, chloroauric acid and sodium thiosulfate were respectively used. Optimally gold
Sulfur sensitized. After sensitization, 4-hydroxy-6-methyl-1-1,3,
3a, 7-Tetrazaindene was added to 1.0 g per mol of silver.

[0117]

[Chemical 1]

The following additives were added to the obtained emulsions (Em-1 to Em-6) to prepare emulsion layer coating solutions. At the same time, a protective layer coating solution described below was also prepared. Using both coating solutions, support at a speed of 80 m / min using two slide hopper type coaters so that the coating amount is 2.0 g / m ² per side and the amount with gelatin is 3.1 g / m ^2. Both sides were simultaneously coated on the body and dried in 2 minutes and 20 seconds to obtain samples No1 to No6. Glycidimethacrylate 50 wt%, methyl acrylate 10 wt%, butyl methacrylate 40 wt%
Polyethylene terephthalate colored blue at a concentration of 0.15 for a 175 μm X-ray film using an aqueous dispersion of a copolymer obtained by diluting the copolymer consisting of the three monomers as described above to a concentration of 10 wt% A film base was used.

The additives used in the emulsion are as follows.
The addition amount is indicated by the amount per mol of silver halide.

1,1-Dimethylol-1-bromo-1-nitromethane 70 mg t-Butyl-catechol 400 mg Polyvinylpyrrolidone (molecular weight 10,000) 1.0 g Styrene-maleic anhydride copolymer 2.5 g Nitrophenyl-triphenylphosphonium chloride 50 mg 1 2,3-Dihydroxybenzene-4-sulfonate ammonium 2g

[0121]

[Chemical 2]

C ₄ H ₉ OCH ₂ CH (OH) CH ₂ N (CH ₂ COOH) ₂ 1 g 1-phenyl-5-mercaptotetrazole 15 mg Protective Layer Solution Next, the following was prepared as a protective layer coating solution. The additives are shown in the amount per liter of coating liquid.

Lime-treated inert gelatin 68 g Acid-treated gelatin 2 g Sodium-i-amyl-n-decylsulfosuccinate 1 g Polymethylmethacrylate (matting agent having an area average particle size of 3.5 μm) 1.1 g Silicon dioxide particles (area average particle size 1.2 μm matting agent) 0.5 g (CH ₂ = CHSO ₂ CH ₂ ) ₂ O (hardener) 500 mg C ₄ F ₉ SO ₃ K 2 mg C ₁₂ H ₂₅ CONH (CH ₂ CH ₂ O) ₅ H 2.0 g

[0124]

[Chemical 3]

Photographic properties were evaluated using the obtained samples No1 to No6. First, the sample is sandwiched between two intensifying screens (KO-250), and the tube voltage is 80 kvp and the tube current is 100 m through an aluminum wedge.
A, X-ray for 0.05 seconds was irradiated and exposed. Next, using an automatic developing machine (SRX-502), processing was performed with a developing solution and a fixing solution having the following formulations.

Developer Formulation Part-A (for 12 liter finish) Potassium hydroxide 450 g Potassium sulfite (50% solution) 2280 g Diethylenetriamine pentaacetic acid 120 g Sodium bicarbonate 132 g 5-Methylbenzotriazole 1.2 g 1-Phenyl-5-mercaptotetrazole 0.2g Hydroquinone 340g Add water to make 5000ml.

Part-B (for finishing 12 liters) Glacial acetic acid 170 g Triethylene glycol 185 g 1-Phenyl-3-pyrazolidone 22 g 5-Nitroindazole 0.4 g Starter glacial acetic acid 120 g Potassium bromide 225 g Add water to make 1.0 l.

Fixer formulation Part-A (for 18-liter finishing) Ammonium thiosulfate (70wt / vol%) 6000g Sodium sulfite 110g Sodium acetate trihydrate 450g Sodium citrate 50g Gluconic acid 70g 1- (N, N-dimethylamino) -Ethyl-5-mercaptotetrazole 18g Part-B (for 18l finishing) Aluminum sulfate 800g To prepare a developer, add Part A and Part B to about 5l of water at the same time, add water while stirring and dissolve and add 12l to finish with glacial acetic acid.
The H was adjusted to 10.40. This is used as a development replenisher.

20 ml / l of the above-mentioned starter was added to 1 liter of this development replenisher to adjust the pH to 10.26 to prepare a working solution.

The fixing solution was prepared by adding Part A and Part B to approximately 5 liters of water.
Was simultaneously added, water was added while stirring and dissolving to make 18 l, and the pH was adjusted to 4.4 using sulfuric acid and NaOH. This is the fixing replenisher.

The processing temperature is 35 ° C. for development and fixing, respectively.
33 ℃, 20 ℃ water wash, 50 ℃ dry, treatment time is dry to dry 45
Seconds.

After the processing, the sensitivity was measured. Sensitivity is expressed as the reciprocal of the exposure dose that gives a density of fog +0.5 Sample No1
The relative sensitivity is shown when the sensitivity of is set to 100. The results obtained are shown in Table 3 below.

In addition, the needle heads 0.3 on the unexposed samples No1 to No6
After applying a load of 5 g with a scratch hardness meter of the needle, the same developing treatment as described above was performed, and the pressure fog density was measured with a microdensitometer. The degree of fog is shown as a relative value when the increase in fog of Sample No. 1 is 100. The results obtained are shown in Table 3 below.

In addition, the pressure characteristics during development (pressure marks by the rollers of the automatic processor, that is, the degree of generation of roller marks) were evaluated as follows. That is, the sample was unexposed and processed in an X-ray automatic developing machine having a special facing type roller having strong unevenness for a processing time of 30 seconds. The treatment liquid used was the same as the above treatment liquid. The roller marks generated at that time were observed, and the evaluation results were classified into the following 5 grades according to their degree.

5: No roller mark was generated.

4: Very slight occurrence.

3: Somewhat occurred. (Within practical tolerance) 2: Many occurrences. (Out of practical tolerance) 1: Very high occurrence The above evaluation results are shown in Table 3.

[0138]

[Table 3]

It can be seen that the sample of the present invention has no or very little roller mark as compared with the comparative sample, and the relative sensitivity and pressure fog are good, and there is no problem in practical use. Further, it can be seen that the medical silver halide photographic light-sensitive material of the present invention has the above effect even in rapid processing.

Example 2 (Preparation of seed emulsion-2) Seed emulsion-2 was prepared as follows.

A3 ossein gelatin 24.2 g Make up to 9657 ml with water.

Polypropyleneoxy-polyethyleneoxy-disuccinate sodium salt (10% ethanol aqueous solution) 6.78 ml potassium bromide 10.8 g 10% nitric acid 114 ml B3 2.5N silver nitrate aqueous solution 2825 ml C3 potassium bromide 840 g Water is made up to 2825 ml.

D3 1.75N aqueous solution of potassium bromide Solution A3 was mixed with solution B3 and solution C3 using the mixing stirrer shown in JP-B-58-58288 and 58-58289 at the following silver potential control amount of 42 ° C.
Nucleation was performed by adding 464.3 ml by the double-sided mixing method over 1.5 minutes.

After stopping the addition of solution B3 and solution C3, it took 60 minutes to raise the temperature of solution A3 to 60 ° C., adjust the pH to 5.0 with 3% KOH, and then add solution B3 again. Solution C3 was added by the double jet method at a flow rate of 55.4 ml / min each for 42 minutes. The silver potential (measured with a silver ion selective electrode using a saturated silver-silver chloride electrode as a reference electrode) during this temperature increase from 42 ° C. to 60 ° C. and re-simultaneous mixing with the solutions B3 and C3 was +10 mv using the solution D3 And +20 mv.

After completion of the addition, the pH was adjusted to 6 with 3% KOH, and desalting and washing with water were immediately performed. In this seed emulsion, 90% or more of the total projected area of silver halide grains has a maximum side ratio of 1.0 to 2.0.
The average thickness of hexagonal tabular grains is 0.
It was confirmed with an electron microscope that the average particle size was 07 μm and the average particle size (circular diameter conversion) was 0.53 μm. The variation coefficient of thickness was 38% and the variation coefficient of the distance between twin planes was 40%.

Preparation of Em-7 A tabular silver halide emulsion Em-7 having an average silver iodide content of 1.5 mol% was prepared using seed emulsion-2 and the following four kinds of solutions.

A4 ossein gelatin 43.71 g Polypropyleneoxy-polyethyleneoxy-disuccinate sodium salt (10% ethanol aqueous solution) 1.00 ml Seed emulsion-2 1.526 mol equivalent Make up to 4000 ml with water.

B4 Potassium bromide 647 g Make up to 1358 ml with water.

C4 Silver nitrate 923 g Make up to 1552 ml with water.

D4 3% by weight of gelatin and silver iodide grains (average grain size: 0.05 μ) Fine grain emulsion (*) equivalent to 0.105 mol * 6.64 liter of 5.0% by weight aqueous gelatin solution containing 0.06 mol of potassium iodide , 7.06 mol of silver nitrate and 2 liters of an aqueous solution each containing 7.06 mol of potassium iodide were added over 10 minutes. The pH during the formation of the fine particles is 2.
The temperature was controlled at 0 and the temperature at 40 ° C. After particle formation, the pH was adjusted to 6.0 using an aqueous sodium carbonate solution.

Solution A4 was vigorously stirred in the reaction vessel while maintaining the temperature at 60 ° C., and part of solution B4, part of solution C4 and solution D4 were added thereto by the simultaneous mixing method over 26 minutes, After that, the remaining amounts of the solution B4 and the solution C4 were successively added over 46 minutes by the simultaneous mixing method. During this time, pH was 5.8 and pA
g kept at 8.6 throughout. Here, the addition rates of the solution B4 and the solution C4 were changed in a function-like manner with respect to time so as to match the critical growth rate. That is, the addition was performed at an appropriate addition rate so that small particles were not generated other than the growing seed particles and polydispersion did not occur due to Ostwald ripening. The rate of addition of the solution D4 was 0.11 with the rate ratio (molar ratio) with the solution C4.
Kept at.

After completion of the addition, this emulsion was cooled to 40 ° C., and a 13.8% (weight) aqueous solution of modified gelatin modified with a phenylcarbamoyl group as a flocculating polymer agent (substitution rate 90%) 800 m
l was added and stirred for 3 minutes. Then, a 56% (weight) acetic acid aqueous solution was added to adjust the pH of the emulsion to 4.6, the mixture was stirred for 3 minutes, allowed to stand for 20 minutes, and the supernatant was drained by decantation. Then, 4.0 liters of distilled water at 40 ° C was added, the mixture was allowed to stand with stirring, the supernatant was drained, and 5.0 liters of distilled water was added.
Was added and the mixture was allowed to stand with stirring, and the supernatant was drained. Subsequently, a gelatin aqueous solution and a 10% (weight) aqueous sodium carbonate solution were added to adjust the pH to 5.80, and the mixture was stirred at 50 ° C. for 30 minutes and redispersed. After redispersion at 40 ℃ pH is 5.80, pAg
Adjusted to 8.06.

When the obtained silver halide emulsion was observed with an electron microscope, tabular silver halide grains having an average grain size of 0.67μ, an average thickness of 0.19μ, an average aspect ratio of about 3.5 and a grain size distribution of 21.9% were obtained. Met. Also, the average distance between twin planes is
0.018μ, 97% (number) of all tabular silver halide grains with a twin plane distance to thickness ratio of 5 or more, 49% with 10 or more grains, and 17% with 15 or more grains. Was occupied.

Further, as a result of obtaining the distribution of the silver iodide content in the grain, when the distance from the center to the side surface is L _b0 and the distance to the point where the silver iodide content is the highest is L _b1 , L _b1 = 0.
89L _b0 , where L _{c0 is} the distance from the center to the main plane and l _c1 is the distance to the point where the silver iodide content is the highest,
It was l _c1 = 0.26 L _c0 .

(Preparation of seed emulsion-3) In seed emulsion-2
Seed emulsion except that the silver potential when raising the temperature from 40 ° C to 60 ° C was +25 mV, the silver potential when re-simultaneous mixing of solutions B3 and C3 was +32 mV, and the time of re-simultaneous mixing was changed from 42 minutes to 60 minutes. Seed Emulsion-3 was prepared in the same manner as in Example 2.

In this seed emulsion, 90% or more of the total projected area of silver halide grains is composed of hexagonal tabular grains having a maximum side ratio of 1.0 to 2.0. The hexagonal tabular grains have an average thickness of 0.12 μm and an average grain size.
It was confirmed with an electron microscope that (converted to a circle diameter) was 0.38 μm. The variation coefficient of thickness was 41% and the variation coefficient of distance between twin planes was 40%.

Preparation of Em-8 The seed emulsion was changed to seed emulsion-3, the pAg at the time of mixing was changed to 8.8, the addition time of the solution D4 was 41 minutes, and the addition speed (speed ratio with the solution C4) As shown in Table 4, Em-8 was prepared in the same manner as Em-7 except that the addition speeds of the solutions B4 and C4 were changed with respect to the particle size.

When the obtained silver halide emulsion was observed with an electron microscope, tabular silver halide grains having an average grain size of 0.67μ, an average thickness of 0.19μ, an average aspect ratio of about 3.5 and a grain size distribution of 17.5% were obtained. Met. Also, the average distance between twin planes is
0.018μ, 97% (number) of all tabular silver halide grains with a twin plane distance to thickness ratio of 5 or more, 49% with 10 or more grains, and 17% with 15 or more grains. Was occupied.

Further, as a result of obtaining the distribution of the silver iodide content in the grain, when the distance from the center to the side surface is L _b0 and the distance to the point where the silver iodide content is the highest is L _b1 , L _b1 = 0.
57 L _b0 , where L _{c0 is} the distance from the center to the main plane and L _c1 is the distance to the point where the silver iodide content is the highest,
L _c1 = 0.63 L _c0 .

Further, the amount of silver iodide within the radius of 0.034 μ from the center was 0%, and the amount of silver iodide within the radius of 0.2 μ was 85%.

[0161]

[Table 4]

Preparation of Em-9 In Em-7, the amounts of potassium bromide and the finishing amount of the solution B4 and the amount of the solution D4 used were changed to B4, C4 and D4.
Was changed to prepare a tabular silver halide emulsion Em-9 having an average silver iodide content of 1.0 mol%. However, D4
The addition rate of was constant at a molar ratio with respect to C4, similar to Em-7.

When the obtained emulsion was observed with an electron microscope, it was tabular silver halide grains having an average grain size of 0.68 μm, an average thickness of 0.19 μ, an average aspect ratio of 3.6 and a grain size distribution of 18%.

Preparation of Em-10 In Em-8, the amounts of potassium bromide and finishing amount of solution B4, and the amount of solution D4 used were changed to B4, C4 and D4.
The tabular silver halide emulsion Em-10 having an average silver iodide content of 1.0 mol% was prepared by changing the addition rate of. Further, the addition rate of D4 was decreased in a molar ratio with respect to C4 as the particle size was increased, similar to Em-8.

When the obtained emulsion was observed with an electron microscope, it was tabular silver halide grains having an average grain size of 0.68 μm, an average thickness of 0.19 μ, an average aspect ratio of 3.6, and a grain size distribution width of 17.5%.

Preparation of Em-11 and 12 Further, tabular silver halide emulsions Em-11 and Em-12 having an average silver iodide content of 0.5 mol% were prepared in the same manner.

A list of emulsions is shown in Table 5 below.

[0168]

[Table 5]

The above-obtained emulsion was treated in the same manner as in Example 1 to prepare coating samples Nos. 7 to 12, and the same evaluation as in Example 1 was carried out.

The results are shown in Table 6. The relative sensitivity and the evaluation of the pressure fog are shown as relative values when the sample No. 7 is 100. The roller mark was evaluated by the above method.

[0171]

[Table 6]

It can be seen from the comparison of emulsions of the same iodide composition of the present invention that the sensitivity is improved. In addition, pressure fog is reduced and roller marks are not generated.
It can be seen that the pressure characteristics are improved. Further, it can be seen that the medical silver halide photographic light-sensitive material of the present invention has the above effect even in rapid processing.

[0173]

The silver halide emulsion comprising the tabular silver halide grains according to the present invention, the silver halide photographic light-sensitive material,
The medical silver halide photographic light-sensitive material and the processing method of the medical silver halide photographic light-sensitive material have high sensitivity and excellent pressure characteristics.

Claims (6)

[Claims] 1. 50% or more of the total projected area of silver halide grains contained in the emulsion are tabular silver halide grains, and the distance L from the center P of the tabular grains to the outer surface thereof is L. The distance L ₁ from P to the point A ₁ where the silver iodide content is the highest is less than 0.67 L, and the distance L ₂ from P to the point A ₂ where the silver iodide content is the lowest is More than 0.58 L, the silver iodide content in the vicinity of A ₁ is not uniform, and the silver iodide content substantially decreases from A ₁ to A ₂ , and the average of the tabular grains A silver halide photographic emulsion having a silver iodide content of less than 2 mol%. 2. The tabular silver halide grain according to claim 1, wherein the distance from the center P of the tabular silver halide grain to the side surface is L _b0 , and the point B ₁ at which the silver iodide content becomes maximum is B _1. Is L _b1 , the distance from the center P to the main plane is L _c0 , and the distance to the point C ₁ where the silver iodide content is the highest is L
_The silver halide photographic emulsion according to claim 1, wherein when represented by _c1 , the following (I) is satisfied. (L _b1 / L _b0 ) <(L _c1 / L _c0 ) ... (I) 3. A tabular silver halide grain having an average silver iodide content of less than 2 mol% is 50% or more of the total projected area of silver halide grains contained in the emulsion. When the grain size is D, 20% or less of the total silver iodide in the grain is contained within a radius of 0.05D from the center of the tabular silver halide grain, and the total silver iodide grain in the grain is contained within a radius of 0.3D from the center. A silver halide photographic emulsion characterized by containing 70% or more of. 4. A silver halide photographic light-sensitive material containing the silver halide emulsion according to claim 1, claim 2 and / or 3. 5. A medical silver halide photographic light-sensitive material containing the silver halide emulsion according to claim 1, claim 2 and / or 3. 6. The medical silver halide photographic light-sensitive material according to claim 5 is processed for a total processing time of 15 to 90 seconds in a processing step including a processing bath containing no hardening agent. A method for processing a medical silver halide photographic light-sensitive material.