JPH10232467A - Radiation image forming assembly - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a high contrast radiation image excellent in sensitivity and sharpness by specifying the characteristic curve of a sensitive material, the weight ratio of a binder to a phosphor in the phosphor layer of an intensifying screen and the average particle diameter of the phosphor. SOLUTION: This radiation image forming assembly has a silver halide photographic sensitive material and a radiation intensifying screen. The γ1 of the characteristic curve of the sensitive material is 2.4-4.5. The γ1 is average gradation connecting Dmin+0.25 to Dmin+2.0 on the characteristic curve in rectangular coordinates with optical density and logarithmic exposure as coordinate axes and the Dmin is the min. density (the sum of substrate density and fog density). The weight ratio of a binder to a phosphor in the phosphor layer of the intensifying screen is 0.1-3.0%, the rate of filling of the phosphor is >=65% and the average particle diameter of the phosphor is <=7μm. The sensitivity of silver halide particles in a photosensitive layer positioned farthest from the substrate is preferably lower than that of silver halide particles in a layer just under the photosensitive layer by 0.02<=logE<=0.5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a radiation image forming assembly, and more particularly, to a radiation image forming assembly comprising a silver halide photographic material and a radiographic intensifying screen.

[0002]

2. Description of the Related Art In recent years, the number of people affected by breast cancer is increasing, and it is becoming a social problem. Breast cancer screening includes palpation, ultrasound imaging, mammography, etc.
In particular, the usefulness of mammography using a radiographic intensifying screen is becoming clear. Previous mammography used an industrial X-ray film to form an image directly with X-rays. However, according to this method, the amount of exposure was a problem. In mammography using a radiographic intensifying screen, the exposure dose is 1/10 to 1/100 that of a direct X-ray image forming method, which is extremely effective in reducing the exposure dose. Currently, the most effective method for breast cancer screening It is becoming.

A disadvantage of mammography using a radiographic intensifying screen is that the resolution is poor. The cause is that the image is blurred by passing through the screen,
In addition, the decrease in the X-ray irradiation amount causes an increase in the quantum mottle, resulting in a decrease in the S / N ratio. Particularly in mammography, an extremely slight difference in X-ray absorption due to a lesion must be imaged. In addition, it is necessary to image a very small lesion called a micro lime image, and this reduction in the S / N ratio is a very important problem.

[0004] Various attempts have been made to improve the resolution. In the X-ray generation apparatus, a molybdenum target was used, and monochromatic X-rays were achieved by a molybdenum filter. Various photosensitive material manufacturers provide various photosensitive materials so as to improve the relationship between sensitivity and resolution. The radiation intensifying screen has been improved in sharpness by improving the adhesion to the film by matting the screen surface. The cassette was also made of carbon resin, and both strength and thinning were compatible, and the loss due to X-ray absorption of the cassette could be reduced.

[0005] In particular, an image in mammography must be imaged with a contrast of an extremely small X-ray absorption difference such as a mammary gland lesion in the breast, and a high-contrast film is required.

However, the relationship between the sensitivity and the resolution has not yet been obtained for a photosensitive material which is sufficiently satisfactory.

On the other hand, the phosphor used in the radiation intensifying screen has a high emission luminance and forms a radiation image with a relatively small radiation dose, so that the radiation exposure dose of the subject can be reduced. The emission intensity of the screen, the sharpness of the image, the granularity, etc. are affected by the size of the phosphor particles, the dispersibility of the phosphor, the uniformity of the phosphor, the filling ratio, etc., and the phosphor filling ratio has a large effect. .

As a means for improving the filling rate of the radiation intensifying screen, a technique for improving the filling rate by compressing a phosphor layer has been proposed. However, the fluorescent material has a defect that the crystal structure is liable to undergo a defect or destruction with respect to pressure, and the sensitivity is likely to be reduced. In addition, in order to prevent the phosphor from being destroyed even when pressure is applied, a large amount of resin must be contained, and the resin ratio in the phosphor layer increases due to the large amount of resin, and light is easily diffused to sharpen. There is a problem that the degree decreases.

Japanese Patent Application Laid-Open No. 3-19636 discloses a technique capable of improving the sharpness of a screen by defining the binder weight ratio and the phosphor filling rate. 11%, and a phosphor filling rate of 60 to 70% is good. "

The upper limit of the phosphor filling rate is 70% because the weight ratio of the binder is as high as 4 to 11%. Therefore, when the phosphor filling rate is increased, the volume ratio of the void, which is a light scattering factor, is increased. It is considered that the light emission is apt to be diffused and the sharpness of the image is deteriorated.

In Japanese Patent Application Laid-Open No. 3-19636, compression heating is used as a means for increasing the filling rate. However, in this method, the compression heating condition must be stricter as the filling rate is increased. In addition, it causes the destruction of the phosphor and the deterioration of the binder, which tends to lower the sensitivity.
In this sense, it can be understood that the upper limit of the phosphor filling rate had to be set to 70%.

Conversely, if the weight ratio of the binder is reduced as in the present invention and no means such as compression heating is employed, or if the compression is weak, the upper limit of the filling rate of the phosphor is limited. Should be much higher than 70%.

However, as described in the above-mentioned JP-A-3-19636, "When the weight ratio of the binder is less than 4%, the strength of the intensifying screen (screen) often decreases remarkably ..." In order to reduce the weight ratio of the binder and maintain the screen strength, some measures are required.

The present inventors have studied the properties of the resin used as the binder, the appropriate solvent, the appropriate dispersion method and the dispersion apparatus, and the optimization of the conditions such as the viscosity of the coating solution, the dispersion strength and the dispersion time. By careful consideration within a range usually performed by those skilled in the art, the binder can cover the phosphor surface thinly and widely to bring the phosphor particles closer to each other, and form a dense and flexible uniform network structure over the entire phosphor layer. Even if the binder weight ratio is 0.1 to 3.0%, the screen strength is maintained, and the phosphor filling rate is high and excellent without compressing or under a weak condition even if compressed. It has been found that a screen capable of providing an image having excellent performance has been obtained, and the present invention has been achieved.

[0015]

SUMMARY OF THE INVENTION An object of the present invention is to provide a single-sided emulsion silver halide photographic material and a single-sided radiation intensifying screen which are capable of obtaining a high-contrast radiation image with excellent sensitivity and sharpness. It is to provide an image forming assembly.

[0016]

The above objects of the present invention have been attained by the following constitutions.

(1) a silver halide photographic material having a photosensitive silver halide emulsion layer on only one side of a support;
In a radiation image forming assembly comprising one radiation intensifying screen disposed on the side of the silver halide photographic material on which the photosensitive silver halide emulsion layer is present, a characteristic curve of the silver halide photographic material Γ1 [in the characteristic curve represented by the orthogonal coordinates of the optical density and the logarithmic exposure amount, a point obtained by adding 0.25 to the minimum density (support density + fog density: hereinafter referred to as Dmin); Average gradation connecting the added points] is 2.4 or more and 4.5 or less, and the weight ratio of the binder to the phosphor in the phosphor layer of the radiation intensifying screen is 0.1% or more and 3.0% or less. And a filling factor of the phosphor is 65% or more, and an average particle diameter of the phosphor is 7 μm or less.

(2) The radiation image forming assembly as described in (1) above, wherein γ1 of the characteristic curve of the silver halide photographic material is 2.9 or more and 3.5 or less.

(3) The silver halide photographic light-sensitive material has two or more light-sensitive silver halide emulsion layers, and the sensitivity of the silver halide grains of the light-sensitive silver halide emulsion layer farthest from the support is low. 3. The radiation image forming assembly according to the above item 1 or 2, wherein the sensitivity is lower than that of silver halide grains in a lower layer adjacent to the photosensitive layer.

(4) In the silver halide photographic material, the silver halide grains of the photosensitive silver halide emulsion layer farthest from the support have a monodisperse core / shell type silver halide having an average aspect ratio of less than 2. The radiation image forming assembly according to any one of claims 1 to 3, wherein the radiation image forming assembly is a grain and has lower sensitivity than a lower silver halide grain adjacent to the photosensitive silver halide emulsion layer.

(5) In the silver halide photographic material, the silver halide grains in the photosensitive silver halide emulsion layer closest to the support are tabular silver halide grains having an average aspect ratio of 2 to less than 10. Wherein the silver halide grains have the highest sensitivity.
A radiation image forming assembly according to any one of the preceding claims.

(6) The radiation image forming assembly as described in any one of (1) to (5) above, wherein in the radiation intensifying screen, the phosphor has an average particle diameter of 4 μm or less.

(7) The radiographic image forming assembly according to any one of (1) to (6) above, wherein the binder contains a resin having a hydrophilic polar group in the radiographic intensifying screen.

(8) In the above-mentioned radiographic intensifying screen, the hydrophilic polar group has —SO ₃ M, —OSO ₃ M, and —COO.
At least one selected from the group consisting of M, -PO (OM ') ₂ , and -OPO (OM') ₂ (where M and M 'are hydrogen atoms or alkali metal atoms such as Li, K, and Na); 8. The radiation image forming assembly according to the above item 7, wherein

(9) In the radiographic intensifying screen, the content of the hydrophilic polar group is 10 ^-7 mol or more and 10 ^-3 mol or less based on 1 g of the total binder contained in the phosphor layer. 9. The radiation image forming assembly according to 7 or 8 above.

(10) In the radiographic intensifying screen, the binder has a weight average molecular weight of 5,000 to 2,000.
10. The radiation image forming assembly according to any one of the items 1 to 9, wherein the number is not more than 00.

(11) The radiographic intensifying screen, wherein the binder is at least one resin selected from polyurethane, polyester, vinyl chloride, polyvinyl butyral, and nitrocellulose. The radiation image forming assembly according to claim 1.

The present invention will be described in more detail. In the silver halide photographic light-sensitive material of the present invention, the sensitivity of the silver halide grains in the photosensitive silver halide emulsion layer (hereinafter referred to as photosensitive layer) farthest from the support is lower than that of the lower layer adjacent to the photosensitive layer. It is preferable that logE = 0.02 to 0.5 lower than silver halide grains, and more preferable that logE = 0.05 to
0.45.

The silver halide grains used in the uppermost layer of the present invention are preferably monodisperse core / shell type silver halide grains. The monodisperse core / shell type silver halide grains in the present invention may be normal grains such as cubic, tetradecahedral, and octahedral grains, or may be spherical grains or twin grains. Twin particles having an aspect ratio of less than 2 are preferred.

In the present invention, the monodisperse silver halide grain is defined as having a silver halide content within a range of ± 20% of the average particle size d of 60% of the total silver halide weight.
The above is mentioned, and preferably 70% or more, more preferably 80% or more.

Here, the average particle diameter d is the particle diameter di when the product ni × di ³ of the frequency ni and di ³ of the particles having the particle diameter di becomes the maximum (3 significant figures, the minimum number is 4). Rounded off). The particle size referred to here is the diameter of spherical silver halide grains, and the diameter of a projected image converted to a circular image of the same area for grains having a shape other than spherical. The particle size is, for example, 1
It can be obtained by magnifying the image from 10,000 times to 50,000 times and actually measuring the particle diameter or the area at the time of photographing on the print. (It is assumed that the number of measured grains is 1000 or more indiscriminately.) Particularly preferred highly monodispersed grains such as monodispersed core / shell type silver halide grains which can be used in the present invention have a broad distribution. Is not more than 20%, and more preferably not more than 15%.

The monodisperse core / shell type silver halide grains which can be used in the present invention are silver halide grains having a grain structure composed of two or more layers having different silver iodide contents. Wherein the particles are composed of a core (inner layer) and a shell covering the core, and the shell is formed by one or more layers. The iodine content of the core and the shell are preferably different from each other, and it is particularly preferable that the iodine content of the core is maximized. The iodine content of the core is preferably 5 mol% or more and the solid solution limit or less, more preferably 7 mol% or more and the solid solution limit or less. The content of the core is preferably at least 3 mol% or more. Further, the iodine content of the core is preferably at least 3 mol% or more than the iodine content of the shell. The iodine distribution of the core is usually uniform, but may have a distribution. For example, as the concentration goes from the center to the outside, the concentration may become higher, or the intermediate region may have a maximum or minimum concentration.

The monodisperse core / shell type silver halide grains of the present invention are prepared by allowing an aqueous solution containing a protective colloid and seed particles to exist in a reaction vessel in advance, and if necessary, silver ions, halogen ions, or silver halide fine particles. Is preferably obtained by growing the seed particles by supplying the same. In this case, the grain center can have a halogen composition region different from that of the core. The halogen composition of the seed particles is optional,
Any of silver bromide, silver iodobromide, silver chloroiodobromide, silver chlorobromide, silver chloride, silver chloroiodide, and silver iodide may be used.

The monodisperse core / shell type silver halide photographic emulsion used in the present invention can be prepared by using a known silver halide solvent such as ammonia, thioether, thiourea or thiocyanate described in JP-A-3-168734. It can be present and be substantially rounded.
In the present invention, the term "substantially rounded" means that the curvature corresponding to 1 / 10L to 1 / 2L with respect to the length L when focusing on the surface having the largest area among the polygons forming the outer shape of the silver halide grains. It is defined as having a radius radius at the ridge of the polygon before spheroidization. Grain roundness can be determined by observing silver halide grains with an electron microscope.

Further, in the monodisperse core / shell type silver halide photographic emulsion used in the present invention, at least 70% of a water-soluble silver salt used for grain formation of the silver halide emulsion is added in the step of forming silver halide grains. PAg after
Is preferably 1 or more larger than the pAg before adding 70% of the water-soluble silver salt so as to be substantially round as defined above, more preferably 1.5 or more. .

In the emulsion thus prepared, an appropriate amount of a halogenated solvent is added to the emulsion at an appropriate time from the time when silver halide grains are formed to the time when chemical ripening starts, at an appropriate time. They may be uniformly mixed and have a substantially rounded shape.

After the formation of the silver halide emulsion, the silver halide emulsion before the solvent treatment may be subjected to a desalting treatment (including washing with water).

The silver halide grains used in the uppermost layer of the present invention can be produced by any of an acidic method, a neutral method, and an ammonia method. A grown silver halide emulsion is preferred, and a silver halide emulsion grown at pH 7.3 or less is more preferred.

The average iodine content of the silver halide grains used in the uppermost layer of the present invention is 0.1 mol% or more larger than the average iodine content of the adjacent lower layer silver halide grains.
It is preferably at most 3 mol%.

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 (E
Electron Probe Micro Analysis
zer method). According to this method, a sample in which emulsion grains are well dispersed so as not to be in contact with each other is prepared, an electron beam is irradiated, and X-ray analysis by electron beam excitation is performed. By determining the characteristic X-ray intensity of silver and iodine emitted from each grain by this method, the silver halide composition of each grain can be determined. When the silver iodide content of at least 50 grains is determined by the EPMA method,
From these averages, the average silver iodide content is determined.

In the present invention, the distribution of the halogen composition inside the silver halide grains can be determined by pretreating the grains into ultrathin sections and then observing and analyzing them with a transmission electron microscope while cooling. Specifically, silver halide grains are taken out of the emulsion, embedded in a resin, and cut with a diamond knife to produce a 60-nm-thick section. This section can be obtained by observation and point analysis with a transmission electron microscope equipped with an energy dispersive X-ray analyzer while cooling the section with liquid nitrogen, and by quantitative calculation (Inoue, Nagasawa: Photographic Society of Japan, 1987) Conference Abstracts p. 62).

In the present invention, the silver iodide content on the outermost surface of the tabular silver halide grains is determined by the XPS method (X-ray
Photoelectron Spectroscope
y: 50 ° depth analyzed by X-ray photoelectron spectroscopy)
Means the silver iodide content of the portion up to and can be determined as follows. The sample was cooled to −110 ° C. or less in an ultra-high vacuum of 1 × 10 ⁻⁸ torr or less, and MgKα was used as a probe X-ray with an X-ray source voltage of 15 kV and an X-ray source current of 40 kV.
Irradiation at mA, Ag3d5 / 2, Br3d, I3d3 /
Measure for two electrons. The integrated intensity of the measured peak is determined by a sensitivity factor.
And the halide composition on the outermost surface is determined from these intensity ratios. The purpose of cooling the sample is to eliminate measurement errors caused by destruction of the sample by X-ray irradiation at room temperature (decomposition of silver halide and diffusion of halide (particularly iodine)), and to enhance measurement accuracy. By cooling to −110 ° C., sample destruction can be suppressed to a level that does not hinder measurement.

The tabular silver halide grains of the present invention are grains having two opposing parallel main planes, and the aspect ratio is represented by the ratio of the grain size to the grain thickness. Here, the particle diameter is an average projected area diameter (hereinafter referred to as a particle diameter).
The projected area of the tabular silver halide grains is represented by a circle-equivalent diameter (diameter of a circle having the same projected area as the silver halide grains), and the thickness is 2 to form tabular silver halide grains.
The distance between two parallel main planes.

The average value of the aspect ratio of the tabular silver halide grains of the present invention is from 2 to less than 10, preferably from 2.0 to less than 5.

In the present invention, in the emulsion layer containing tabular silver halide grains, 50% or more of the total projected area is composed of tabular silver halide grains, preferably 70% or more, more preferably 90% or more. . The average grain size of the tabular silver halide grains of the present invention is preferably from 0.15 to 5.0 µm, more preferably from 0.4 to 3.0 µm, most preferably from 0.4 to 2.0 µm. 0 μm. The average thickness of the tabular silver halide grains of the present invention is from 0.15 to
It is preferably 0.3 μm, and the particle size and thickness can be optimized to optimize sensitivity and other photographic properties. Sensitivity and other factors that make up the photosensitive material that affect photographic properties (thickness of hydrophilic colloid layer, hardness,
The optimal particle size and the optimal thickness vary depending on the conditions of chemical ripening, the sensitivity of the photosensitive material, the amount of silver, etc.).

In the tabular silver halide grains of the present invention, silver iodochloride, silver chloroiodobromide, silver chlorobromide, silver bromide, silver iodobromide and the like can be used as silver halide. The content of silver iodide is preferably less than 2 mol%, more preferably 0.5 mol% or more and less than 2 mol% as an average silver iodide content in the whole silver halide grains.

The tabular silver halide grains contained in the silver halide emulsion of the present invention preferably have a more uniform iodine content between grains. When the distribution of iodine content between grains was measured by the EPMA method, the relative standard deviation was 3
It is preferably at most 5%, more preferably at most 20%.

In the present invention, the tabular silver halide grains contain silver iodide, but the location of the silver iodide is preferably localized. When the localization position is inside, it is more preferable that it exists at least at the center. It is also preferred that it be present on the outermost surface.

The average iodine content of the outermost surface of the tabular silver halide used in the present invention is 2 mol% to 15 mol%.
Or less, more preferably 3 mol% or more and 12 mol% or less.

The tabular silver halide grains of the present invention may have dislocations. Dislocations are described in F. Hamilt
on, Photo. Sci. Eng, 57 (1967)
And T. Shiozawa, J .; Soc. Photo. S
ci. Japan, 35, 213 (1972) and can be observed by a direct method using a low-temperature transmission electron microscope. In other words, the silver halide grains taken out so as not to apply enough pressure to cause dislocations in the grains from the emulsion are placed on a mesh for electron microscopic observation, and the sample is prepared so as to prevent damage (printout, etc.) by electron beams. Observation is performed by a transmission method in a state of cooling. At this time,
The thicker the particles, the more difficult it is for the electron beam to pass,
High pressure type (200 kV for 0.25 μm thick particles)
The above can be observed more clearly using an electron microscope.

The tabular silver halide grains of the present invention are preferably monodisperse emulsions having a narrow grain size distribution. Specifically, (standard deviation of grain size / average grain size) × 100 = broad grain size distribution (% ) Is preferably 25% or less, more preferably 20% 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) × 100 = width (%) of thickness distribution, it is preferably 25% or less, more preferably 20%. These are:

In order to obtain the tabular silver halide grains and the monodisperse core / shell type silver halide grains of the present invention, the conditions for enlarging the produced seed grains are described in
-39027, 55-142329, 58-1
Nos. 13928, 54-48521 and 58-49
As can be seen in No. 938, a water-soluble silver salt solution and a water-soluble halide solution are added by a double jet method, and the addition rate is set within a range in which new nucleation does not occur and Ostwald ripening does not occur in accordance with the enlargement of particles. There is a method of gradually changing the value. As another condition for enlarging the seed grains, a method of adding silver halide fine grains, dissolving and recrystallizing the grains, as shown in Item 88 of the Abstracts of the 58th Annual Meeting of the Photographic Society of Japan, may be used.

For growth, an aqueous silver nitrate solution and an aqueous halide solution can be added by double jet.
The iodine can be supplied into the system as silver iodide. The addition rate is preferably such that no new nuclei are generated and at a rate such that the size distribution does not spread due to Ostwald ripening, that is, 30 to 100% of the rate at which new nuclei are generated. In producing the silver halide emulsion of the present invention, stirring conditions during production are extremely important. As the stirrer, an apparatus described in JP-A-62-160128, in which an additive liquid nozzle is installed in the liquid near the mother liquor suction port of the stirrer, is particularly preferably used. In this case, the rotation speed of the stirring is preferably set to 100 to 1200 rpm. In preparing the emulsion of the present invention, a known silver halide solvent such as ammonia, thioether, or thiourea may be present during the seed grain forming step and the growth of the seed grains.

In the preparation of the silver halide grains of the present invention, during the growth, a silver salt solution and a halide solution are added by a double jet method. Particles having a desired particle size and distribution can be obtained by a method in which the size distribution does not spread due to aging, that is, a method in which the size is gradually changed within the range of 30 to 100% of the rate at which new nuclei are generated.

The silver halide grains of the present invention may be so-called halogen conversion type (conversion type) grains. The halogen conversion amount is from 0.2 mol% to the silver amount.
It is preferably 0.5 mol%, and the conversion may be performed during physical ripening or after completion of physical ripening. As a method of halogen conversion, an aqueous halogen solution or fine silver halide particles having a solubility product with silver smaller than the halogen composition on the grain surface before the halogen conversion is usually added. The fine particle size at this time is preferably 0.2 μm or less, more preferably 0.02 μm or less.
０．１0.1 μm.

When silver iodide is contained in the outermost surface of the silver halide grains of the present invention, a method for preparing the emulsion containing silver halide grains as a base is to simultaneously use a silver nitrate solution and a solution containing iodide ions. A method of adding silver iodide, a method of adding silver halide fine particles such as silver iodobromide or silver chloroiodobromide, and a method of adding potassium iodide or a mixture of potassium iodide and potassium bromide can be applied. . Of these, the method of adding fine silver halide grains is preferable. Particularly preferred is the addition of silver iodide fine grains. The timing of adjusting the silver iodide content on the outermost surface is selected from the final stage of the silver halide crystal production process to the chemical ripening process and further to the end of the solution preparation process immediately before the application of the silver halide emulsion. However, it is preferable to adjust by the end of the chemical ripening step. The chemical ripening step referred to here is a point in time when physical ripening and desalting of the silver halide emulsion of the present invention are completed, when a chemical sensitizer is added, and thereafter, an operation for stopping chemical ripening is performed. Up to. The addition of silver halide fine grains may be carried out several times at intervals, or another chemically-ripened emulsion may be added after the addition of the fine grains.

The temperature of the emulsion of the present invention at the time of adding the silver halide fine grains is preferably in the range of 30 to 80 ° C., more preferably 40 to 65 ° C. Further, the present invention is preferably carried out under the condition that part or all of the silver halide fine grains to be added disappears immediately before coating immediately after the addition, more preferably 20% of the added silver halide fine grains. The above is the disappearance immediately before the application.

In the present invention, it is preferable to add a silver halide solvent before the desalting step in order to accelerate the developing speed. For example, a thiocyanate compound (potassium thiocyanate, sodium thiocyanate, ammonium thiocyanate, etc.) is used in an amount of 1 × 10 ⁻³ mol or more and 3 × 10 ³ mol or more per mol of silver.
It is preferable to add ^-2 mol or less.

In the present invention, gelatin is preferably used as a dispersion medium for the protective colloid of the silver halide grains. As the gelatin, alkali-treated gelatin, acid-treated gelatin, low molecular weight gelatin (having a molecular weight of 1000 to 5) is preferable.
And modified gelatin such as phthalated gelatin. Other hydrophilic colloids can also be used. Specifically, Research Disclosure Magazine (Resea
rc Disclosure. RD)
76 volume No. 17643 (December 1978).

In the preparation of the tabular silver halide grains of the present invention, unnecessary soluble salts may be removed during the growth of the silver halide grains, or they may be contained.
The removal of the salts can be carried out according to the method described in RD-17643, section II.

Further, the silver halide grains of the present invention can be used in the course of grain formation and / or growth in the course of cadmium salt, zinc salt, lead salt, thallium salt, iridium salt (including complex salt), rhodium salt (complex salt). ) And at least one metal ion selected from iron salts (including complex salts) so that these metal elements can be contained inside the particles and / or in the particle surface layer. By placing in an atmosphere, a reduction sensitizing nucleus can be provided inside the grain and / or on the grain surface.

The effect of the reducing agent added at a desired point in time of particle formation is to add an oxidizing agent such as hydrogen peroxide (water) and its adduct, peroxoacid salt, ozone, and I ₂ at a desired point in time. It is preferable to deactivate and suppress or stop the reducing agent. The oxidizing agent may be added at any time from when the silver halide grains are formed to before the addition of a gold sensitizer (or a chemical sensitizer if no gold sensitizer is used) in the chemical sensitization step.

In the silver halide photographic emulsion of the present invention, unnecessary soluble salts may be removed at the end of the growth of silver halide grains, or may be kept contained. The removal of the salts can be carried out according to the method described in RD-17643, section II, and the silver halide grains of the present invention can be subjected to chemical sensitization. The conditions of the step of chemical ripening or chemical sensitization, for example, pH, pAg, temperature, time and the like are not particularly limited, and they can be carried out under conditions generally used in the art. For chemical sensitization, sulfur sensitization using a compound containing sulfur that can react with silver ions or active gelatin, selenium sensitization using a selenium compound, tellurium sensitization using a tellurium compound, using a reducing substance A reduction sensitization method, gold or another noble metal sensitization method using a noble metal or the like can be used alone or in combination.

The amount of the selenium sensitizer used depends 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. Depending on the properties of the selenium compound to be used, the addition may be carried out by dissolving in water or an organic solvent such as methanol or ethanol alone or in a mixed solvent. Further, a method in which the mixture is added in advance with a gelatin solution, or a method in which the mixture is added in the form of an emulsified dispersion of a mixed solution with a polymer soluble in an organic solvent by the method disclosed in JP-A-4-140739 may be used. The temperature of chemical ripening using a selenium sensitizer is preferably in the range of 40 to 90C, more preferably 45C or more and 80C or less. The pH is 4 ~
9, pAg is preferably in the range of 6 to 9.5. The technology for using the tellurium sensitizer is based on the technology for using the selenium sensitizer.

It is also preferable to perform so-called reduction sensitization on the surface of the grains by placing the grains in an appropriate reducing atmosphere. Preferred examples of the reducing agent include thiourea dioxide and ascorbic acid and derivatives thereof. Other preferable reducing agents include polyamines such as hydrazine and diethylenetriamine, dimethylamineboranes, sulfites and the like. The amount of the reducing agent
It is preferable to change depending on the type of reduction sensitizer, particle size of silver halide grains, composition and crystal habit, environmental conditions such as reaction system temperature, pH, pAg, and the like. When about 0.01 to 2 mg per mole of silver halide is used as a guide, preferable results can be obtained. In the case of ascorbic acid, the range is preferably about 50 mg to 2 g per mol of silver halide. Conditions for the reduction sensitization are a temperature of about 40 to 70 ° C. and a time of about 10 to 200.
Preferably, the pH and the pAg are in the range of about 5 to 11 and about 1 to 10, respectively.

One of the reduction sensitization techniques by adding a water-soluble silver salt
A so-called silver ripening, which is a seed, is performed. Silver nitrate is preferred as the water-soluble silver salt. The pAg during silver ripening is suitably from 1 to 6, and preferably from 2 to 4. Conditions such as temperature, pH, and time are preferably in the above-described reduction sensitization condition range.

The silver halide grains in the present invention may be spectrally sensitized with a methine dye or the like. Dyes used include cyanine dyes, merocyanine dyes, complex cyanine dyes, complex merocyanine dyes, holopolar cyanine dyes, hemicyanine dyes, styryl dyes, and hemioxonol dyes. Particularly useful dyes are those belonging to the cyanine dyes, merocyanine dyes and complex merocyanine dyes. These dyes can be applied to any of the nuclei usually used. That is, a pyrroline nucleus, an oxazoline nucleus, a thiazoline nucleus, a pyrrole nucleus, an oxazole nucleus, a thiazole nucleus, a selenazole nucleus, an imidazole nucleus,
A nucleus in which a hydrocarbon ring is fused to these nuclei such as a tetrazole nucleus and a pyridine nucleus, that is, an indolenine nucleus, a benzoindolenine nucleus, an indole nucleus, a benzoxazole nucleus, a naphthoxazole nucleus, a benzothiazole nucleus, a naphthothiazole nucleus, Selenazole nucleus, benzimidazole nucleus, quinoline nucleus and the like can be applied. These nuclei may have a substituent on a carbon atom. In a merocyanine dye or a complex merocyanine dye, as a nucleus having a ketomethine structure, a pyrazolin-5-one nucleus, a thiohydantoin nucleus, a 2-thiooxazolidine-2,4-dione nucleus, a thiazoline-2,4-dione nucleus, a rhodanine nucleus, A 5- to 6-membered heterocyclic nucleus such as a thiobarbituric acid nucleus can be applied.

These sensitizing dyes may be used alone or in combination, and the combination is often used particularly for supersensitization. In addition, the emulsion layer may contain, in addition to the sensitizing dye, a dye having no spectral sensitization or a substance which does not substantially absorb visible light and exhibits a supersensitizing effect. The sensitizing dye is nucleated, grown, desalted,
It may be added during or during each step of chemical sensitization or after chemical sensitization.

In the photographic light-sensitive material of the present invention, an appropriate amount of a hardener is added in advance in the coating step of the light-sensitive material so as to be suitable for rapid processing, and the water swelling ratio in the development-fixing-washing step is adjusted. By doing so, it is preferable to reduce the water content in the photosensitive material before the start of drying.

The swelling ratio of the silver halide light-sensitive material of the present invention during development is preferably from 150 to 250%, and the film thickness after expansion is preferably 70 μm or less. 250% water swelling
If the temperature exceeds the limit, drying failure occurs, and for example, conveyance failure also occurs in automatic developing machine processing, particularly in rapid processing. On the other hand, when the water swelling ratio is less than 150%, development unevenness and residual color tend to increase when developed. The water swelling ratio as referred to herein means the difference between the film thickness after swelling in each processing solution and the film thickness before development processing, and this is divided by the film thickness before processing and multiplied by 100. .

The silver halide photographic light-sensitive material of the present invention is irradiated with X-rays through an acrylic wedge through a radiation intensifying screen, exposed to light, developed and processed to obtain the optical density and logarithmic exposure of a sample obtained by developing. In the characteristic curve represented by rectangular coordinates, γ1 of the characteristic curve (average gradation connecting a point obtained by adding 0.25 to the minimum density and a point obtained by adding 2.0 to the minimum density) of the characteristic curve is 2.4 or more. 4.5 or less. Here, the minimum concentration is the concentration obtained by adding the fog concentration to the support concentration.

In the present invention, powder processing agents, tablets, pills,
Solid processing agents such as granules may be used, and those subjected to moisture-proof treatment as needed may be used. The powder in the present invention refers to an aggregate of fine crystals. The term “granules” as used in the present invention refers to granules having a particle diameter of 50 to 5000 μm, which are obtained by adding a granulation step to powder. The tablet referred to in the present invention refers to a tablet obtained by compressing powder or granules into a certain shape.

As a cause of fluctuations in photographic performance, it is effective to reduce the aperture coefficient of a developing solution in an automatic developing machine. In particular, the aperture coefficient is preferably 80 cm ² / l or less. That is, when the opening coefficient exceeds 80 cm ² / l, the undissolved solid processing agent and the concentrated liquid immediately after dissolution are susceptible to air oxidation, and as a result, insolubles and scum are generated, and the solid processing machine or processing is performed. Although problems such as contamination of the photosensitive material occur, the aperture coefficient is 80%.
These problems are solved at m ² / l or less. The opening coefficient referred to here is represented by the area of contact with air per unit volume of the processing solution, and the unit is (cm ² / l). Opening coefficient of preferably 80 cm ² / l or less in the present invention, more preferably 50~3cm ² / l, more preferably from 35~10cm ² / l. The aperture coefficient can be generally reduced by using a floating pig as a resin or the like for shutting off the air, or disclosed in JP-A-63-131138 and JP-A-63-21605.
Nos. 0 and 63-235940.

The solid processing agent used in the present invention is a developer,
Although used for photographic processing agents such as fixing agents and rinsing agents, it is the developer that has a great effect of the present invention, especially an effect of stabilizing photographic performance. In the solid processing agent used in the present invention, only one part of a certain processing agent may be solidified, but preferably, all components of the processing agent are solidified.
It is desirable that each component is molded as a separate solid processing agent and is mounted in the same unit. It is also desirable that the separate components are packaged in the order in which they are periodically and repeatedly placed in a package.

In the present invention, as a supply means for supplying the solid processing agent to the processing tank, for example, when the solid processing agent is a tablet, Japanese Unexamined Utility Model Publication No. 63-137783 and 63-975.
No. 22, Japanese Utility Model Laid-Open No. 1-85732, etc., but any method may be used as long as the function of supplying the tablets to the processing tank is provided at a minimum. When the solid processing agent is a granule or a powder, Japanese Utility Model Application Laid-Open No. 62-81964, 6
3-84151, JP-A-1-292375, and the gravity drop method described in JP-A-63-105159 and JP-A-63-105159.
There is a known method using a screw or a screw described in 195345 or the like, but the method is not limited thereto.

The place where the solid processing agent of the present invention is charged may be in a processing tank, but is preferably in communication with a processing section for processing a photographic material, and a processing liquid flows between the processing section and the processing section. And a structure in which there is a constant processing solution circulation amount with the processing unit and the dissolved components move to the processing unit. The solid processing agent is preferably introduced into a processing liquid whose temperature is controlled.

In the developer, in addition to dihydroxybenzenes, aminophenols and pyrazolidones described in JP-A-6-138591 (pages 19 to 20), reductones described in JP-A-5-165161 are used as developing agents. Are also preferably used. Pyrazolidones used, particularly those substituted at the 4-position (dimesone, dimesone S, etc.)
Is particularly preferable because the water-soluble property and the change of the solid processing agent itself with the passage of time are small.

As a preservative, in addition to the sulfite described in JP-A-6-138591, an organic reducing agent can be used as a preservative. In addition, a bisulfite adduct of a chelating agent or a hardening agent can be added. Further, as silver sludge inhibitor, JP-A-5-289255, JP-A-6-308
It is also preferable to add a compound described in No. 680 (general formulas [4-a] and [4-b]). Addition of a cyclodextrin compound is also preferable, and compounds described in JP-A-1-124852 are particularly preferable.

An amine compound can be added to the developer, and the compounds described in US Pat. No. 4,269,929 are particularly preferred.

It is necessary to use a buffer for the developer. Examples of the buffer include sodium carbonate, potassium carbonate,
Sodium bicarbonate, potassium bicarbonate, trisodium phosphate, tripotassium phosphate, dipotassium phosphate, sodium borate, potassium borate, sodium tetraborate (borate), potassium tetraborate, o-hydroxybenzoic acid Sodium (sodium salicylate), potassium o-hydroxybenzoate, sodium 5-sulfo-2-hydroxybenzoate (sodium 5-sulfosalicylate), potassium 5-sulfo-2-hydroxybenzoate (potassium 5-sulfosalicylate) and the like. Can be mentioned.

Examples of the development accelerator include JP-B-37-160.
Nos. 88, 37-5987, 38-7826, 44-12380, 45-9019 and U.S. Pat. No. 3,813,247; No. 50-15554
Quaternary ammonium salts represented by JP-A-50-137726, JP-B-44-30074, JP-A-56-156826 and JP-A-52-43429. US Patent 2,61
P-aminophenols described in U.S. Pat. Nos. 0,122 and 4,119,462; U.S. Pat. Nos. 2,494,903, 3,128,182, 4,230,796 and 3,253. No. 919, JP-B-41-11431, U.S. Pat. Nos. 2,482,546, 2,596,926 and 3,582,346, and the like. 42-25201
No. 3,128,183, JP-B-41-11
Nos. 431 and 42-23883 and U.S. Pat.
2,501 or the like, a polyalkylene oxide,
In addition, 1-phenyl-3-pyrazolidones, hydrozines, mesoionic compounds, ionic compounds, imidazoles, and the like can be added as necessary.

As antifoggants, alkali metal halides such as potassium iodide and organic antifoggants can be used. Examples of the organic antifoggant include benzotriazole, 6-nitrobenzimidazole, 5-nitroisoindazole, 5-methylbenzotriazole, 5-nitrobenzotriazole, 5-chloro-benzotriazole, 2-thiazolyl-benzimidazole, Nitrogen-containing heterocyclic compounds such as 2-thiazolylmethyl-benzimidazole, indazole, hydroxyazaindolizine and adenine can be exemplified by 1-phenyl-5-mercaptotetrazole as a typical example.

Further, if necessary, the developer composition
Methyl cellosolve, methanol, acetone, dimethylformamide, cyclodextrin compounds, and other compounds described in JP-B-47-33378 and JP-B-44-9509 can be used as an organic solvent for increasing the solubility of the developing agent. Furthermore, various additives such as a stain inhibitor, an anti-sludge agent, and a layering effect promoter can be used.

As the fixing agent, a compound known as a fixing agent can be added. Fixing agents, chelating agents, pH buffers, hardeners,
Preservatives and the like can be added.
2246 (p. 4) and JP-A-5-113632 (2-
4) can be used. In addition, a bisulfite adduct of a hardener and a known fixing accelerator can also be added.

Prior to the treatment, it is preferable to add a starter, and it is also preferable to add the starter after solidifying it. As the starter, in addition to an organic acid such as a polycarboxylic acid compound, a halide of an alkaline earth metal such as KBr, an organic inhibitor, and a development accelerator are used.

In general, hydroquinones are often used as a developing agent in a developing solution used for developing a silver halide black-and-white photographic light-sensitive material. And substantially free of hydroquinones from the viewpoint of environmental protection, for example, US Pat.
A developer using ascorbic acid described in 236,816 may be used.

The development time of the silver halide photographic light-sensitive material of the present invention is 3 to 90 seconds, more preferably 5 to 60 seconds, and the processing time is 15 to 210 seconds by dry to dry, more preferably 15 to 210 seconds. 90 seconds.

In the silver halide photographic light-sensitive material of the present invention, various additives can be further added to the silver halide emulsion depending on the purpose. Examples of additives and others used are RD-17643 (December 1978), 1871
6 (November 1979) and 308119 (1989)
December, December). The locations of those descriptions 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 IVA desensitizing dye 23 IV 998 IVB dye 25-26 VIII 649-650 1003 VIII Development accelerator 29 XXI 648 Upper right antifoggant / stabilizer 24 IV 649 Upper right 1006-7 VI Brightener 24 V 998 V Hardener 26 X 651 Left 1004-5 X Surface activity 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 Used in the silver halide photographic light-sensitive material of the present invention. The support can be, for example, 2 of the aforementioned RD-17643
8 and RD-308119, page 1009.

A suitable support is a plastic film or the like, and the surface of the support may be provided with an undercoat layer for improving the adhesion of the coating layer, or may be subjected to corona discharge, ultraviolet irradiation or the like.

Next, the radiation intensifying screen (hereinafter, also simply referred to as a screen) of the present invention will be described. In the screen of the present invention, the weight of the binder with respect to the weight of the phosphor in the phosphor layer is set to 0.1% or more and 3.0% or less, and the dispersing ability of the binder with respect to the phosphor is improved. The binder is thinly and uniformly present on the surface, so that the phosphor particles can approach each other, so that the packing ratio is improved. That is, a phosphor layer with a high filling rate can be obtained without using any means such as compression. When the weight of the binder is 0.1% or more and 3.0% or less with respect to the weight of the phosphor in the phosphor layer, the filling rate of the phosphor is 6%.
5% or more.

In general, the phosphor layer is made up of phosphor particles, a binder and voids free of these. Here, the void refers to a space in the phosphor layer in which the phosphor particles and the binder are not substantially present. Therefore, the volume ratio of the voids in the phosphor layer increases as the amount of the binder decreases. Since this gap acts as a light scattering factor, diffusion of light emission from the phosphor can be prevented and sharpness can be improved.

The weight of the binder relative to the weight of the phosphor is 3.0.
%, The voids in the layer are reduced, so that the light scattering is reduced, and the emitted light is easily diffused, so that the sharpness of the image is deteriorated. When the weight of the binder is less than 0.1%, it is difficult for the binder to widely cover the surface of the phosphor, and it is difficult for the binder to perform the intrinsic function of binding the phosphors to each other. Can not be obtained. In addition, the binder is hard to be uniform throughout the entire layer, so that the phosphor is unlikely to be uniformly present, resulting in non-uniform light emission and degraded image granularity. Further, it is not preferable in that the phosphor layer is fragile and easily damaged.

In the present invention, the particle size of the phosphor is measured by
The phosphor is dispersed in water using an appropriate surfactant, and a light scattering particle size measuring device (for example, LA-91 manufactured by Distillery Co., Ltd.)
The particle size was measured using 0). In the present invention, the particle size of the phosphor is 7 μm or less, preferably 4 μm or less.

The phosphor filling rate in the phosphor layer was measured by removing the protective layer of the screen, eluting the entire phosphor layer using an organic solvent, filtering and drying, and then using an electric furnace at 600 ° C.
The weight of the phosphor after baking for 1 hour to remove the resin on the surface is
g, when the phosphor layer thickness before elution is Pcm, the screen area used for elution is Qcm ² , and the specific gravity of the phosphor is Rg / cm ³ , the phosphor filling rate = [O ÷ (P × Q × R)] It is a value calculated by × 100.

The binder usable in the present invention includes, for example, polyurethane, vinyl chloride copolymer, vinyl chloride
Vinyl acetate copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-acrylonitrile copolymer, butadiene-acrylonitrile copolymer, polyamide resin, polyvinyl butyral, cellulose derivative (nitrocellulose etc.), styrene-butadiene copolymer And various synthetic rubber resins, phenol resins, epoxy resins, urea resins, melamine resins, phenoxy resins, silicone resins, acrylic resins, urea formamide resins, and the like.
Among them, it is preferable to use polyurethane, polyester, vinyl chloride copolymer, polyvinyl butyral, and nitrocellulose.

The weight average molecular weight of the binder is 5000 to 20
0000 is particularly preferred. In particular, the binder preferably used according to the present invention contains a resin having a hydrophilic polar group. The hydrophilic polar group is adsorbed on the phosphor surface to improve the dispersibility of the phosphor particles and prevent the aggregation of the phosphor particles, thereby improving the coating stability, sharpness, and granularity.

Of the resins having a hydrophilic polar group preferably used in the present invention, particularly preferred are -SO ₃ M,-
_{OSO 3 M, -COOM, -PO (} OM ') 2 and -OP
O (OM ') ₂ (where M and M' are hydrogen atoms or L
It is a resin having at least one hydrophilic polar group (negative functional group) composed of an alkali metal atom such as i, K, and Na).

Next, a polyurethane which is an example of a resin having a hydrophilic polar group and is preferably used in the present invention will be described.

The polyurethane can be synthesized by using a generally used reaction between a polyol and a polyisocyanate. As the polyol component, a polyester polyol obtained by reacting a polyol with a polybasic acid is generally used. Therefore, if the monomer having a hydrophilic polar group is used as a raw material, a polyurethane or polyester polyol having a hydrophilic polar group can be synthesized.

Examples of the polybasic acids include phthalic acid, isophthalic acid, terephthalic acid, adipic acid, azelaic acid, sebacic acid, maleic acid and the like.

Examples of polybasic acids having a hydrophilic polar group include 5-sulfoisophthalic acid, 2-sulfoisophthalic acid, 4-sulfoisophthalic acid, 3-sulfophthalic acid,
-Dialkyl sulfoisophthalate, dialkyl 2-sulfoisophthalate, dialkyl 4-sulfoisophthalate,
Examples include dialkyl 3-sulfophthalates and their sodium and potassium salts.

Examples of polyols include trimethylolpropane, hexanetriol, glycerin, trimethylolethane, neopentyl glycol, pentaerythritol, ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, , 6-hexanediol, diethylene glycol, cyclohexanedimethanol, and the like.

The polyester polyol having another hydrophilic polar group introduced therein can be synthesized by a known method. If a polyester polyol having such a hydrophilic polar group is used as a raw material, a polyurethane having a hydrophilic polar group can be synthesized.

Examples of the polyisocyanate component include diphenylmethane-4,4-diisocyanate, hexamethylene diisocyanate, tolylene diisocyanate,
Examples thereof include 1,5-naphthalene diisocyanate, tolidine diisocyanate, lysine isocyanate methyl ester, and isophorone diisocyanate.

As another method of synthesizing a polyurethane, the polyurethane can be synthesized by adding a polyurethane having an OH group and the following compound containing a hydrophilic polar group and a chlorine atom. M and M 'are hydrogen atoms,
It is an alkali metal atom or an alkyl group.

ClCH ₂ CH ₂ SO ₃ M ClCH ₂ CH ₂ OSO ₃ M ClCH ₂ PO (OM ′) ₂ ClCH ₂ COOM The introduction of a hydrophilic polar group into a polyurethane is known, and the addition of —SO ₃ Polyurethane UR8300 having a Na group (manufactured by Toyobo Co., Ltd.) and polyurethane TIM-6001 having a COOH group (Sanyo Chemical Co., Ltd.)
) Can be easily obtained as a commercial product.

As the binder, the following resins having a functional group can be used in addition to the above resins.

For example, when the weight average molecular weight is 5,000 to 2
000, vinyl chloride copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-acrylonitrile copolymer, butadiene-acrylonitrile copolymer, polyamide resin, polyvinyl resin Butyral, cellulose derivatives (such as nitrocellulose), styrene-butadiene copolymer, various synthetic rubber resins, phenol resins, epoxy resins, urea resins, melamine resins, phenoxy resins, silicone resins, acrylic resins, urea formamide resins, etc. Is mentioned. Among them, polyester, vinyl chloride copolymer,
It is preferable to use polyvinyl butyral and nitrocellulose.

The vinyl chloride resin preferably used is, for example, a copolymer containing a polar group and a chlorine atom as shown below in a copolymer containing an OH group, such as a vinyl chloride-vinyl alcohol copolymer. It can be synthesized by addition through a reaction.

ClCH ₂ CH ₂ SO ₃ M ClCH ₂ CH ₂ OSO ₃ M ClCH ₂ PO (OM ') ₂ ClCH ₂ COOM There is also a method of copolymerizing all monomers as copolymerizable monomers. That is, a predetermined amount of a reactive monomer having an unsaturated bond into which a repeating unit containing a hydrophilic polar group is introduced is poured into a reaction vessel such as an autoclave, and a general polymerization initiator such as BPO (benzoyl peroxide) and AI is used.
Radical polymerization initiators such as BN (azobisisobutyronitrile), redox polymerization initiators, anionic polymerization initiators,
Polymerization can be performed using a polymerization initiator such as a cationic polymerization initiator. For example, specific examples of the reactive monomer for introducing sulfonic acid or a salt thereof include unsaturated hydrocarbon sulfonic acids such as vinyl sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid, p-styrene sulfonic acid, and the like. Salts.

Further, sulfoalkyl esters of acrylic acid or methacrylic acid such as 2-acrylamido-2-methylpropanesulfonic acid, sulfoethyl (meth) acrylate, sulfopropyl (meth) acrylate and salts thereof, Or ethyl acrylate-2-sulfonate and the like can be mentioned.

A carboxylic acid or a salt thereof is introduced (COO
When (M is introduced), (meth) acrylic acid, maleic acid or the like may be used, and when phosphoric acid or a salt thereof is introduced, (meth) acryl-2-phosphate may be used.

The introduction of a hydrophilic polar group into a vinyl chloride copolymer is known. Examples of commercially available products include a vinyl chloride-vinyl acetate copolymer having a —SO ₃ K group, MR110 (Nippon Zeon Co., Ltd.). -SO ₃ N
Examples of the polyester having an a group include Byron 280 (manufactured by Toyobo Co., Ltd.).

The type of the hydrophilic group can be identified by using an analyzer such as NMR (nuclear magnetic resonance), and can be quantified by an analyzer such as WDX (wavelength dispersive X-ray fluorescence). For example, S in SO ₃ M was determined as follows.

To the matrix resin, a predetermined amount of a P-containing compound and sulfur having a purity of 99.9999% were added with varying amounts of addition as an internal standard substance, and the fluorescent X-rays of S and P were added by WDX (wavelength dispersive fluorescent X-ray). The intensity ratio was determined and a calibration curve of the content of S atoms was prepared. Then, a predetermined amount of the P-containing compound was added to the measurement sample, and the WDX was measured.

It is preferable for the dispersion of the phosphor that the hydrophilic polar group be contained in an amount of 10 ^-7 mol or more and 10 ^-3 mol or less based on 1 g of the binder contained in the phosphor layer. More preferably 1
It is ^0-7 mol or more and ^10-4 mol or less.

In the present invention, a resin containing a hydrophilic polar group and a resin containing no hydrophilic polar group may be mixed.
Examples of the resin that does not contain a hydrophilic polar group that can be mixed include polyurethane, polyester, and vinyl chloride copolymer having a weight average molecular weight of 5,000 to 200,000 (for example,
Vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-acrylonitrile copolymer), butadiene-acrylonitrile copolymer, polyamide resin, polyvinyl butyral, cellulose derivative (nitrocellulose, etc.), styrene -Butadiene copolymers, various synthetic rubber resins, phenol resins, epoxy resins, urea resins, melamine resins, phenoxy resins, silicone resins, acrylic resins, urea formamide resins and the like. Among them, polyurethane, polyester,
It is preferable to use a vinyl chloride copolymer, polyvinyl butyral, or nitrocellulose.

Also in this case, it is preferable that the hydrophilic polar group is contained in an amount of 10 ⁻⁷ mol to 10 ⁻³ mol per 1 g of the binder contained in the phosphor layer.

Preferred phosphors used for the radiation intensifying screen of the present invention include the following.

A tungstate-based phosphor (CaWO ₄ ,
MgWO, CaWO ₄ : Pb, etc.), terbium-activated rare earth oxysulfide phosphors [Y ₂ O ₂ S: Tb, Gd ₂ O ₂ S: T
b, La ₂ O ₂ S: Tb, (Y, Gd) ₂ O ₂ S: Tb,
(Y, Gd) O ₂ S: Tb, Tm, etc.], terbium-activated rare earth phosphate-based phosphor (YPO ₄ : Tb, GdPO ₄ : T
b, LaPO ₄ : Tb, etc.), terbium-activated rare earth oxyhalide phosphor (LaOBr: Tb, LaOB)
r: Tb, Tm, LaOCl: Tb, LaOCl: T
b, Tm, LaOCl: Tb, Tm, LaOBr: T
b, GdOBr: Tb, GdOCl: Tb, etc., thulium-activated rare earth oxyhalide-based phosphor (LaOB)
r: Tm, LaOCl: Tm, etc.), barium sulfate-based phosphor [BaSO ₄ : Pb, BaSO ₄ : Eu ²⁺ , (Ba, S
r) SO ₄ : Eu ²⁺ etc.] divalent europium activated alkaline earth metal phosphate phosphor [(Ba ₂ PO ₄ ) ₂ : Eu
²⁺ , (Ba ₂ PO ₄ ) ₂ : Eu ^2+, etc.], divalent europium-activated alkaline earth metal fluoride halide-based phosphor [B
aFCl: Eu ²⁺ , BaFBr: Eu ²⁺ , BaFCl:
Eu ²⁺ , Tb, BaFBr: Eu ²⁺ , Tb, BaF _2.
BaCl.KCl: Eu ²⁺ , (Ba.Mg) F ₂ .Ba
Cl.KCl: Eu ²⁺ etc.], iodide phosphor (CsI:
Na, CsI: Tl, NaI, KI: Tl, etc.), sulfide-based phosphor [ZnS: Ag (Zn, Cd) S: Ag, (Z
n, Cd) S: Cu, (Zn, Cd) S: Cu, Al
Etc.), a hafnium phosphate-based phosphor (HfP ₂ O ₇ : Cu
Etc.), tantalate-based phosphors (YTaO ₄ , YTaO ₄ :
Tm, YTaO ₄ : Nb, [Y, Sr] TaO _4-x : N
b, LuTaO ₄ , LuTaO ₄ : Nb, [Lu, Sr]
TaO _4-x : Nb, GdTaO ₄ : Tm, Gd ₂ O ₃ · Ta
₂ O ₅ .B ₂ O ₃ : Tb, etc.) However, the phosphor used in the present invention is not limited to these, and any phosphor that emits light in the visible or near ultraviolet region upon irradiation with radiation may be used. it can.

In a method for producing a radiographic intensifying screen, as a first production method, a phosphor coating solution comprising a binder and a phosphor (hereinafter referred to as a phosphor coating) is applied on a support to form a phosphor layer. I do.

As a second production method, a sheet is formed from a phosphor coating, placed on a support, and adhered to the support at a temperature equal to or higher than the softening temperature or melting point of the binder contained in the phosphor coating. Manufactured in process.

As a method for forming a phosphor layer on a support,
The above two types are conceivable, but any method may be used as long as it is a method for uniformly forming the phosphor layer on the support, and a method such as spraying may be used.

The phosphor layer of the first production method can be produced by applying a phosphor coating material in which a phosphor is uniformly dispersed in a binder solution on a support and drying it.

The sheet to be used as the phosphor layer in the second production method was prepared by applying a phosphor paint on the temporary support for forming the phosphor sheet or on the protective film applied on the temporary support and drying. Thereafter, it can be manufactured by peeling from the temporary support.

That is, first, a binder and phosphor particles are added to an appropriate organic solvent, and stirred and mixed using a disperser or a ball mill to prepare a phosphor coating material in which the phosphor is uniformly dispersed in the binder. I do.

Examples of the solvent for preparing the phosphor coating include lower alcohols such as methanol, ethanol, n-propanol and n-butanol, hydrocarbons containing chlorine atoms such as methylene chloride and ethylene chloride, acetone, methyl ethyl ketone, methyl isobutyl ketone and the like. Ketones, aromatic compounds such as toluene, benzene, cyclohexane, cyclohexanone, and xylene; esters of lower fatty acids such as methyl acetate, ethyl acetate, and butyl acetate with lower alcohols; dioxane; ethylene glycol monoethyl ester; ethylene glycol monomethyl ester; And mixtures thereof.

In the phosphor coating, a dispersing agent for improving the dispersibility of the phosphor in the coating or a bonding force between the binder and the phosphor in the phosphor layer after formation is used. Various additives such as a plasticizer may be mixed.

Examples of dispersants include phthalic acid, stearic acid, caproic acid, lipophilic surfactants and the like.

Examples of the plasticizer include triphenyl phosphate,
Phosphoric acid esters such as tricresyl phosphate and diphenyl phosphate, phthalic acid esters such as diethyl phthalate and dimethoxyethyl phthalate, glycolic acid esters such as ethyl phthalyl ethyl glycolate and butyl phthalbutyl butylate, and triethylene glycol and adipic acid Examples thereof include polyesters, polyesters of polyethylene glycol and aliphatic dibasic acids such as polyesters of diethylene glycol and succinic acid, and the like.

The coating film of the paint is formed by uniformly applying the phosphor paint containing the phosphor and the binder prepared as described above to the surface of the support or the temporary support for sheet formation. I do.

As the coating means, for example, a doctor blade, a roll coater, a knife coater, an extrusion coater or the like can be used.

As the support and the temporary support, those made of various materials such as glass, wool, cotton, paper, and metal can be used. What can be processed into a sheet or a roll is preferred. From this point, for example, cellulose acetate film, polyester film, polyethylene terephthalate film, polyamide film, polyimide film, triacetate film, plastic film such as polycarbonate film, metal sheet such as aluminum foil and aluminum alloy foil, general paper and photographic base paper Base paper for printing, such as coated paper or art paper, baryta paper, resin coated paper, paper sized with polysaccharides as described in Belgian Patent 784,615, pigments such as titanium dioxide Pigmented paper containing, and processed paper such as paper sized with polyvinyl alcohol are particularly preferred.

In the second production method, a phosphor paint is applied on the temporary support or the protective film applied on the temporary support, dried, and then separated from the temporary support to form a phosphor layer. And Therefore, it is preferable that a release agent is applied to the surface of the temporary support in advance so that the formed phosphor sheet is easily peeled from the temporary support.

In order to strengthen the bond between the support and the phosphor layer, an undercoat layer is applied to the surface of the support by applying a polymer substance such as polyester or gelatin to impart adhesion, and sensitivity, image quality (sharpness, granularity, etc.) In order to improve the property, a light reflecting layer made of a light reflecting substance such as titanium dioxide or a light absorbing layer made of a light absorbing substance such as carbon black may be provided. The configuration thereof can be arbitrarily selected depending on the purpose, application, and the like, but in the present invention, a carbon black-containing black polyethylene terephthalate support is preferred.

Further, the phosphor layer of the present invention may be compressed. By compressing the phosphor layer, the packing density of the phosphor can be further improved, and the sharpness and granularity can be further improved. As a compression method, a press machine, a calender roll, or the like can be used.

In the case of the first production method, the phosphor layer and the support are compressed as they are.

In the case of the second production method, the obtained phosphor sheet is placed on a support, and the sheet is adhered to the support while being compressed at a temperature not lower than the softening temperature or the melting point of the binder.

As described above, the sheet can be spread thinly by utilizing the method of pressing the phosphor sheet on the support without previously fixing it.

Usually, the radiation intensifying screen is provided with a protective layer for physically and chemically protecting the surface of the phosphor layer on the side opposite to the side in contact with the support described above. Such a protective layer is preferably provided also in the present invention. The thickness of the protective layer is generally in the range of 2 to 20 μm.

The protective layer is made of, for example, a cellulose derivative such as cellulose acetate or nitrocellulose, or a synthetic polymer such as polymethyl methacrylate, polyethylene terephthalate, polyvinyl butyral, polyvinyl formal, polycarbonate, polyvinyl acetate, or vinyl chloride / vinyl acetate copolymer. It can be formed by a method in which a solution prepared by dissolving in a suitable solvent is applied to the surface of the phosphor layer. These polymer substances can be used alone or in combination. When the protective layer is formed by coating, it is desirable to add a crosslinking agent immediately before coating.

Alternatively, it can be formed by a method such as bonding a plastic sheet made of polyethylene terephthalate, polyethylene naphthalate, polyethylene, polyvinylidene chloride, polyamide or the like using an adhesive.

The protective layer used in the present invention is preferably formed of a coating film containing a fluorine resin soluble in an organic solvent. The fluorine-based resin refers to a polymer of an olefin containing fluorine (fluoroolefin) or a copolymer containing an olefin containing fluorine as a copolymer component. The protective layer formed by the coating film of the fluorine-based resin may be cross-linked. The protective layer made of fluororesin can easily remove dirt such as fats and plasticizers coming out of the photosensitive material by contact with tentacles or photosensitive materials. There are advantages that can be done. Further, for the purpose of improving the film strength, etc., a fluorine-based resin and another polymer substance may be mixed.

Further, the protective layer is preferably a synthetic resin layer having a thickness of 10 μm or less formed on the phosphor layer. By using such a thin protective layer, particularly in the case of a radiographic intensifying screen, the distance from the phosphor to the silver halide emulsion is shortened, which contributes to the improvement of the sharpness of the obtained radiographic image. Further, the phosphor layer can be colored with a color (such as red or yellow) having an absorption at the emission wavelength of the phosphor to improve sharpness. Further, the thickness of the phosphor layer is preferably 20 to 150 μm,
It is desirable that the thickness be up to 120 μm.

[0147]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited by these examples.

Example 1 <Preparation of silver halide grains> (Preparation of normal crystal seed emulsion) Seed emulsion-A was prepared as follows.

A1 ossein gelatin 100 g potassium bromide 2.05 g 11.5 l with water B1 ossein gelatin 55 g potassium bromide 65 g potassium iodide 1.8 g 0.2N sulfuric acid 38.5 ml water 2.6 l C1 ossein gelatin 75 g Potassium bromide 950 g Potassium iodide 27 g 3.0 l with water D1 95 g silver nitrate 2.7 l with water E1 1410 g silver nitrate 3.2 l with water Control solution A1 solution B1 and solution D1 are kept at 60 ° C. The solution was added over 30 minutes by the jet method, and then the C1 and E1 solutions were added over 105 minutes by the control double jet method. Stirring is 5
The test was performed at 00 rpm. The flow rate was such that no new nuclei were generated with the growth of the particles and so-called Ostwald ripening was performed, and the flow rate was such that the particle size distribution did not spread. At the time of adding the silver ion solution and the halide ion solution, the pAg was adjusted to 8.3 ± 0.05 using a potassium bromide solution, and the pH was adjusted to 2.0 ± 0.1 using sulfuric acid.

After the addition, the pH was adjusted to 6.0, and then extraneous salts were removed to remove extraneous salts.
A desalting treatment was performed by the method described in No. 6. When this seed emulsion was observed with an electron microscope, the average particle size was 0.27 μm,
This was a cubic monodisperse emulsion having a cubic shape with a slightly widened corner having a distribution area of 17%.

Preparation of Em-1 A monodisperse core / shell emulsion was prepared using Seed Emulsion-A and the following solution.

[0152] A2 ossein gelatin _{95.40g HO (CH 2 CH 2)} m- (CH (CH 3) CH 2 O) 17 - (CH 2 CH 2 O) n -H (m + n ≒ 5.7 molecular weight 1700) (10% methanol solution) 3 ml 28% ammonia aqueous solution 897.6 ml 56% acetic acid aqueous solution 1356 ml seed emulsion-A 4.577 mol equivalent water 10200 ml B2 ossein gelatin 52.8 g potassium bromide 109.8 g potassium iodide 65.4 g With water 2640 ml C2 ossein gelatin 72 g Potassium bromide 1821 g With water 3600 ml D2 silver nitrate 224.4 g 28% aqueous ammonia 183 ml With water 2640 ml E2 Silver nitrate 2598 g 28% aqueous ammonia (28%) 2119 ml With water 4369.2 ml F2 1.75 N odor Potassium iodide aqueous solution G 256% acetic acid aqueous solution A2 solution was kept at 60 ° C., and B2 was added to A2 solution stirred with a stirrer.
The solution and the solution D2 were added by the double jet method in 22 minutes.
After the addition of the B2 solution and the D2 solution, the C2 solution and the E2 solution were further added by a double jet method in 42 minutes. Here, B2
The addition rates of the solution and the solution D2, and the solution C2 and the solution E2 are changed in a function with respect to time so as to match the critical growth rate, and polydispersion is caused by generation of small particles other than the growing seed crystal and Ostwald ripening. It was added at an appropriate addition rate so as not to cause the

By using the F2 solution and the G2 solution, the pAg for particle growth was maintained at 7.8, the pH was maintained at 7, and the D
35 minutes after the start of the addition of the two liquids (75% of the total used amount of silver nitrate)
Was added at a constant flow rate over 4 minutes. During this time, the pAg changed from 7.8 to 10.1. The pH was kept at 7 throughout. After the addition was completed, acetic acid was further added to adjust the pH to 6.0.

In order to remove excess salts, precipitation and desalting were carried out using an aqueous solution of Demol (manufactured by Kao Atlas Co., Ltd.) and an aqueous solution of magnesium sulfate.
An emulsion having a pAg of 8.55 and a pH of 5.85 was obtained at 40 ° C. Observation of the obtained emulsion under an electron microscope revealed a rounded tetrahedral monodispersed core / shell emulsion having an average diameter of 0.45 μm, a distribution width of 15%, and an average iodine content of 2.3 mol%. Was.

(Preparation of Tabular Seed Emulsion) Seed emulsion-B was prepared as follows.

A3 Ossein gelatin 24.2 g Water 9657 ml Polypropylene oxy-polyethylene oxy-disuccinate sodium salt (10% ethanol aqueous solution) 6.78 ml KBr 10.8 g 10% nitric acid 114 ml B3 2.5N AgNO ₃ aqueous solution 2825 ml C3 KBr 824 g KI 23.5 g 2825 ml with water D3 1.75 N KBr aqueous solution The following silver potential control amount At 35 ° C, JP-B-58-58288 and 58-5828
Using a mixing stirrer described in the specification of No. 9, 464.3 ml of each of the solution B3 and the solution C3 was added to the solution A3 by a simultaneous mixing method over 2 minutes to form nuclei. Solution B3
After the addition of the solution C3 was stopped, the temperature of the solution A3 was raised to 60 ° C. over a period of 60 minutes, and p was added with 3% KOH.
After adjusting the H to 5.0, the solution B3 and the solution C3 were again mixed at a flow rate of 55.4 ml / min by a simultaneous mixing method.
Added for 2 minutes. During the heating from 35 ° C to 60 ° C and re-mixing with solutions B3 and C3, the silver potential (saturated silver-
Measured with silver ion selective electrode using silver chloride electrode as reference electrode)
Was controlled to +8 mV and +16 mV, respectively, using solution D3.

After the addition was completed, the pH was adjusted to 6 with 3% KOH, and immediately, desalting and washing were performed. In this seed emulsion, 90% or more of the total projected area of the silver halide grains is composed of hexagonal tabular grains having a maximum adjacent side ratio of 1.0 to 2.0. The average thickness of the hexagonal tabular grains is 0.065 μm, and the average diameter is 0.065 μm. (Circle diameter conversion)
Was found to be 0.52 μm by an electron microscope.

Preparation of Em-2 (Preparation of fine grain silver iodide emulsion) 5000 ml of a 5.0% by weight gelatin solution containing 0.128 mol of potassium iodide
Then, 1500 ml each of an aqueous solution containing 5.24 mol of silver nitrate and 5.24 mol of potassium iodide was added over 35 minutes. During this time, the temperature was kept at 40 ° C. The average particle size of the obtained silver iodide fine particles was 0.05 μm. Seed emulsion
B and tabular silver halide emulsion E using the following solution
m-2 was prepared.

[0159] A4 ossein gelatin _{45.37g HO (CH 2 CH 2)} m- (CH (CH 3) CH 2 O) 17 - (CH 2 CH 2 O) n -H (m + n ≒ 5.7 molecular weight 1700) (10% methanol solution) 3 ml seed emulsion-1.624 mol equivalent of B 4200 ml of water 42.3 g of B4 ossein gelatin 2309 g of potassium bromide 4850 ml of water 4293 g of C4 silver nitrate 5538 ml of water D4 fine grain silver iodide emulsion 0.18 mol E4 2.0N aqueous potassium bromide solution B4 solution, C4 solution and D
Four liquids were added by the double jet method in 90 minutes.

Here, the addition rate of the B4 solution and the C4 solution was changed in a function-like manner with respect to time so as to correspond to the critical growth rate, and increased by generation of small particles other than the growing seed crystal and Ostwald ripening. The addition was performed at an appropriate rate so as not to disperse. The supply of the D4 solution, that is, the fine grain silver iodide emulsion, was changed with respect to the particle size (addition time) with the speed (molar ratio) to the C4 solution being 0.2, and the total amount of the C4 solution was 4.6. The addition was completed at the time of% addition. Further, by using the E4 solution, the pAg for particle growth was kept at 9.15 throughout. After completion of the addition, in order to remove excess salts, precipitation and desalting are performed using an aqueous solution of Demol (manufactured by Kao Atlas Co., Ltd.) and an aqueous solution of magnesium sulfate, gelatin is added and redispersed. 85 emulsions were obtained. Observation of the obtained emulsion under an electron microscope revealed tabular silver halide grains having an average diameter of 1.04 μm, a distribution width of 20%, an average iodine content of 1 mol% and an average aspect ratio of 4.3.

<Preparation of silver halide photographic light-sensitive material> Each of the obtained silver halide emulsions (Em-1) and (Em-2) was heated to 55 ° C and then treated with 4-hydroxy-6-
An appropriate amount of methyl-1,3,3a, 7-tetrazaindene and a predetermined amount of spectral sensitizing dyes A and B (A: B = 100: 1)
Weight ratio) as a dispersion of solid fine particles, and 10 minutes later, an appropriate amount of chloroauric acid, sodium thiosulfate and ammonium thiocyanate were added to start chemical ripening,
Thirty minutes later, a fine grain silver iodide emulsion was added in an amount of 0.05 mol% per mol of silver halide, and after optimal chemical ripening, 4-hydroxy-6-methyl-1,3 was added at the end of ripening. , 3a, 7-Tetrazaindene was added and stabilized.

[0162]

Embedded image

A dispersion of the spectral sensitizing dye in the form of solid fine particles was prepared by a method according to the method described in JP-A-5-297496. That is, a predetermined amount of the spectral sensitizing dye is
In addition to water whose temperature has been adjusted to 35, a high speed stirrer (dissolver)
Obtained by stirring at 00 rpm for 30-120 minutes.

Next, the following additives were added to each of the chemically sensitized emulsions to prepare a photosensitive silver halide emulsion coating solution. The additives are as follows, and the amount of addition is shown in terms of the amount per mole of silver halide.

1,1-Dimethylol-1-bromo-1-nitromethane 70 mg t-butyl-catechol 70 mg polyvinylpyrrolidone (molecular weight 10,000) 1.0 g styrene-maleic anhydride copolymer 2.0 g nitrophenyl-triphenyl Phosphonium chloride 5 mg 2-anilino-4,6-dimercaptotriazine 10 mg Ammonium 1,3-dihydroxybenzene-4-sulfonate 2 g C ₄ H ₉ OCH ₂ CH (OH) CH ₂ N (CH ₂ COOH) ₂ 1 g 1- Phenyl-5-mercaptotetrazole 15mg 2-Mercaptobenzimidazole-5-sodium sulfonate 8mg

[0166]

Embedded image

At the same time, a protective layer coating solution was prepared. The additives used in the protective layer solution are as follows, and the amount added is 1 liter of the coating solution.
Shown per unit.

Lime-treated inert gelatin 68 g Acid-treated gelatin 2 g Sodium-i-amyl-n-decylsulfosuccinate 1 g Polymethyl methacrylate (a matting agent having an area average particle size of 3.5 μm) 1.1 g Silicon dioxide (area average particle size) 1.2 μm matting agent) 0.5 g (CH ₂ ＣＨCHSO ₂ CH ₂ ) ₂ O (hardening agent) 250 mg C ₄ F ₉ SO ₃ K 2 mg 40% aqueous solution of glyoxal (hardening agent) 5.0 ml

[0169]

Embedded image

The resulting emulsion coating solution and protective layer coating solution were
Film sample 1 was prepared by applying a blue-colored 175 μm thick undercoated polyethylene terephthalate film base previously coated with the following back layer on the opposite side of the emulsion layer,
An emulsion layer in which each of (m-1) and (Em-2) was mixed at 2.2 g / m ^2. Film sample 2 was (Em-1) in the upper layer and 2.2 g / m (Em-2) in the lower layer. ^{2 In} the emulsion layer used, the amount of silver was 4.4 g / m ² , the amount of gelatin in the emulsion coating solution was 4.0 g / m ² , and the amount of gelatin in the protective film was 1.15 g / m ^2. Using a slide hopper type coater, simultaneous coating was performed on the support at a speed of 85 m / min to produce film samples 1 and 2.

The additives used in the back layer are as follows, and the additives are shown in the amount per liter of the coating solution. The back layer was coated so that the amount of gelatin added was 5 g / m ² .

Lime-treated inert gelatin 68 g

[0173]

Embedded image

Polymethyl methacrylate (matting agent having an area average particle size of 5 μm) 1.1 g Silicon dioxide (matting agent having an area average particle size of 1.2 μm) 0.5 g Formalin 37% aqueous solution (hardening agent) 0.9 ml Glioxal 40 % Aqueous solution (hardener) 0.9 ml sodium chloride 0.1 g <Preparation of radiographic intensifying screen> Phosphor (Gd ₂ O ₂ S:
Tb, the average particle size is described in Table 1) and the binder (resin) shown in Table 1 are used in a weight ratio shown in Table 1, and the paint viscosity is 2
A solvent in which methyl ethyl ketone and toluene were mixed at a ratio of 1: 1 was added so as to obtain 0 Ps (poise), and the mixture was mixed and dispersed in a ball mill for 6 hours to obtain a fluorescent paint.

Next, a fluorescent paint was applied to carbon black-containing black polyethylene terephthalate (support thickness 250 μm) horizontally placed on a glass plate using a knife coater so that the dry thickness of the phosphor layer was 80 μm, followed by drying.
A fluorescent layer was obtained.

After forming the fluorescent layer, a polyester-based adhesive is applied to one side of a polyethylene terephthalate film having a thickness of 9 μm, the adhesive surface is brought into close contact with the fluorescent layer, and a protective layer is provided on the fluorescent layer. Was prepared.

The film samples 1 and 2 obtained and the radiographic intensifying screen obtained by the above method were arranged on the side where the silver halide emulsion layer was present, and a radiographic image forming assembly was prepared as shown in Table 1. did. The obtained radiation image forming assembly was passed through an acrylic wedge at a tube voltage of 27 kVp and a tube current of 100 mA for 0.5 second using an X-ray generator manufactured by Toshiba Corporation.
The film sample was exposed to X-rays on a radiation image forming assembly disposed on the X-ray tube side.

Using the obtained film sample and the radiographic intensifying screen shown in Table 1, a rectangular wave chart was photographed in the same manner as described above.

Then, an automatic developing machine [manufactured by Konica Corporation. SR
X-502] with a developer and a fixer of the following formulation.

Developer Formulation Part-A (for finishing 12 L) Potassium hydroxide 450 g Potassium sulfite (50% solution) 2280 g Diethylenetriaminepentaacetic acid 120 g Sodium bicarbonate 132 g 5-Methylbenzotriazole 1.2 g 1-Phenyl-5-mercapto 0.2 g of tetrazole 340 g of hydroquinone Add water to make up to 5000 ml 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 Add 225 g of water to make 1.0 liter.

Fixer Formulation Part-A (for finishing 18 liters) Ammonium thiosulfate (70 wt / vol%) 6000 g sodium sulfite 110 g sodium acetate trihydrate 450 g sodium citrate 50 g gluconic acid 70 g 1- (N, N-dimethylamino) -Ethyl-5-mercaptotetrazole 18g Part-B (for finishing 18l) Aluminum sulfate 800g To prepare a developing solution, add PartA and PartB to about 5l of water at the same time, add water while stirring and dissolving, and make 12l to finish with glacial acetic acid. Was adjusted to 10.40. This is used as a development replenisher.

The starter described above was added at 20 ml / l to 1 liter of the development replenisher to adjust the pH to 10.26 to obtain a working solution.

The fixer was prepared by adding Part A, P to about 5 l of water.
artB was added at the same time, and water was added while stirring and dissolving.
and the pH was adjusted to 4.4 using sulfuric acid and NaOH. This is used as a fixing replenisher.

The processing temperature was 35 ° C. for development, 33 ° C. for fixing, 20 ° C. for washing, 50 ° C. for drying, and the processing time was Dry.
90 seconds for to Dry.

The contrast was evaluated for each film sample obtained by irradiating X-rays through an acrylic wedge through a radiation intensifying screen, exposing the film to light, and developing. Contrast is the lowest density +
This represents a gradient from 0.25 to the minimum density +2.0.

The sensitivity is represented by the reciprocal of the exposure required to obtain a density of fog + 1.0, and is expressed as a ratio (%) with respect to the sample 27 with the sample 27 as 100.

Regarding the evaluation of sharpness, a rectangular wave chart was photographed through a radiation intensifying screen, and the MTF of each film sample obtained by developing was measured by a contrast method.
Was measured. Note that the sharpness of each sample is determined by a spatial frequency of 3 (1
(p / mm) using a sample 27 of 100
And expressed as a ratio (%) to Sample 27. The results are shown in Table 1.

[0188]

[Table 1]

As is clear from Table 1, the image of the radiation image forming assembly obtained by combining the silver halide photographic light-sensitive material of the present invention and the radiation intensifying screen of the present invention has high contrast, high sensitivity and excellent sharpness. You can see that it is.

[0190]

According to the present invention, excellent sensitivity and sharpness can be obtained.
A radiation image forming assembly comprising a single-sided emulsion silver halide photographic material and a single-sided radiation intensifying screen capable of obtaining a high-contrast radiation image could be provided.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI G03C 1/46 G03C 1/46 G21K 4/00 G21K 4/00 B (72) Inventor Yoshihiro Haga 1 Sakuracho, Hino City, Tokyo Konica Stock Company In-house

Claims (11)

[Claims] 1. A silver halide photographic material having a photosensitive silver halide emulsion layer only on one side of a support, and a silver halide photographic material disposed on the side of the support on which the photosensitive silver halide emulsion layer is present. In the radiation image forming assembly composed of one radiation intensifying screen, the characteristic curve γ1 of the characteristic curve of the silver halide photographic light-sensitive material [in the characteristic curve represented by the orthogonal coordinates of the optical density and the logarithmic exposure amount, Density (support density + fog density: hereinafter referred to as Dmin) 0.2
5 is added to the point obtained by adding 2.0 to Dmin] is 2.4 or more and 4.5 or less, and the weight of the binder with respect to the phosphor in the phosphor layer of the radiation intensifying screen. The ratio is 0.1% or more and 3.0% or less, the filling factor of the phosphor is 65% or more, and the average particle diameter of the phosphor is 7%.
A radiation image forming assembly having a size of submicron or less. 2. The radiation image forming assembly according to claim 1, wherein γ1 of the characteristic curve of the silver halide photographic light-sensitive material is 2.9 or more and 3.5 or less. 3. The silver halide photographic light-sensitive material has two or more photosensitive silver halide emulsion layers, and the sensitivity of the silver halide grains of the photosensitive silver halide emulsion layer farthest from the support is adjusted. 3. The radiation image forming assembly according to claim 1, wherein the radiation image forming assembly has a lower sensitivity than silver halide grains in a lower layer adjacent to the photosensitive layer. 4. In the silver halide photographic light-sensitive material, monodisperse core / shell type silver halide grains having an average aspect ratio of less than 2 are contained in the photosensitive silver halide emulsion layer furthest from the support. The radiation image forming assembly according to any one of claims 1 to 3, wherein the sensitivity is lower than that of lower silver halide grains adjacent to the photosensitive silver halide emulsion layer. 5. In the silver halide photographic material, the silver halide grains in the photosensitive silver halide emulsion layer closest to the support are tabular silver halide grains having an average aspect ratio of 2 or more and less than 10. The radiation image forming assembly according to any one of claims 1 to 4, wherein the silver halide grains have the highest sensitivity. 6. The radiation image forming assembly according to claim 1, wherein in the radiation intensifying screen, the phosphor has an average particle diameter of 4 μm or less. 7. The radiation image forming assembly according to claim 1, wherein in the radiation intensifying screen, the binder contains a resin having a hydrophilic polar group. 8. The radiation intensifying screen, wherein the hydrophilic polar group has —SO ₃ M, —OSO ₃ M, —COOM,
PO (OM ') ₂ and -OPO (OM') ₂ (where M
8. The radiation image forming assembly according to claim 7, wherein M and M 'are at least one selected from the group consisting of a hydrogen atom and an alkali metal atom such as Li, K, and Na. 9. In the radiation intensifying screen, the content of the hydrophilic polar group in the whole binder 1 contained in the phosphor layer is reduced.
9. The radiation image forming assembly according to claim 7, wherein the amount is 10 ^-7 mol or more and 10 ^-3 mol or less based on g. 10. The radiographic intensifying screen,
The radiation image forming assembly according to any one of claims 1 to 9, wherein the binder has a weight average molecular weight of 5,000 to 200,000. 11. The radiographic intensifying screen,
The radiation image forming assembly according to any one of claims 1 to 10, wherein the binder is at least one resin selected from polyurethane, polyester, vinyl chloride, polyvinyl butyral, and nitrocellulose.