JP3427287B2 - Image forming method for silver halide photographic material - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-quality radiographic intensifying screen used in an X-ray image forming method and a silver halide photographic light-sensitive material used therewith.

[0002]

2. Description of the Related Art As a method of obtaining a radiation image for medical diagnosis and a non-destructive radiation image of various objects and using the radiation image for diagnosis and radiation inspection, mainly photographic light-sensitive materials such as silver halide and radiation sensitization are used. Using a radiographic method combined with a screen, or a stimulable phosphor that emits the accumulated radiation energy in the form of fluorescence after being excited by electromagnetic waves such as visible light and infrared rays after absorbing the radiation energy A radiation image conversion method can be used.

In the radiographic method, radiation transmitted through a subject or emitted from a subject is irradiated onto a phosphor of a radiographic intensifying screen to excite it to convert it into visible light and expose a silver halide photographic light-sensitive material. Then, a radiation image is formed by developing the image for diagnosis and inspection. These radiographic images are obtained by placing a radiation intensifying screen on both sides or one side of a silver halide photographic light-sensitive material (hereinafter referred to as a light-sensitive material) having a silver halide emulsion layer on both sides or one side of a support, and passing through the subject. To irradiate radiation to form an image.

Since the phosphor has a high emission brightness and can form a radiation image with a relatively small radiation dose, the radiation exposure dose of the subject can be reduced, but the sharpness and graininess of the image depend on the size of the phosphor particles. It is known to be done.

Therefore, various measures are taken to improve the image quality of the radiographic intensifying screen. That is,
JP-A-63-179300 discloses a technique for improving the sharpness and graininess by reducing the particle size of the phosphor on the surface side of the radiation intensifying screen.

However, when the particle size of the phosphor is reduced, the amount of light emitted from the phosphor itself is reduced, the light emission by the phosphor is increased, and the light emitted inside the phosphor layer is difficult to reach the surface and the sensitivity is lowered.

Therefore, there has been a demand for a radiation intensifying screen excellent in sharpness and graininess without lowering sensitivity due to scattering of phosphor particles, and a radiation image forming method using the silver halide photographic light-sensitive material suitable for the radiation intensifying screen.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to reduce the sensitivity due to light scattering of phosphor particles in a radiation image forming method using a radiation intensifying screen using a phosphor and a silver halide photographic light-sensitive material. Another object of the present invention is to provide an image forming method which does not cause deterioration in sharpness.

[0009]

The above-mentioned object can be achieved by the following constitution.

(1) In the image forming method of exposing a silver halide photographic light-sensitive material with X-rays using a radiation intensifying screen, the radiation intensifying screen has two or more phosphor layers, and the phosphor layer Of the above, the phosphor layer farthest from the support contains phosphor particles having a particle diameter of 0.01 μm or more and ½ or less of the main emission wavelength of the phosphor,
The silver halide photographic light-sensitive material is a silver halide grain in which the average projected area diameter of the contained silver halide grains is 1.2 times or more different, and the silver halide emulsion layer has a large grain size. A method for forming an image of a silver halide photographic light-sensitive material, characterized in that the silver halide emulsion layer containing grains is on the side closer to the support.

(2) At least one of the silver halide emulsion layers has an average projected area diameter of 0.3 with an aspect ratio of 2 to 6.
˜0.6 μm with at least one layer having an aspect ratio of 4
The method for forming an image of a silver halide photographic light-sensitive material according to item (1), which is an emulsion layer containing silver halide grains having an average projected area diameter of 0.6 to 1.5 μm.

The present invention will be described in detail below.

The radiographic intensifying screen of the present invention has a phosphor layer containing phosphor particles dispersed in a binder on a support, and the average of the phosphor particles used in the phosphor layer farthest from the support. The particle size is 0.01 μm or more and is ½ or less of the main emission wavelength of the phosphor, preferably 0.01
It is not less than μm and not more than ¼ of the main emission wavelength of the phosphor.

The main emission wavelength of the phosphor of the present invention refers to the main phosphor spectrum of the emission spectrum of the phosphor, and indicates the peak wavelength of the peak having the highest emission intensity.

For example, CaWO ₄ has a wavelength of 420 nm (0.
42 μm) and 544 nm for Gd ₂ O ₂ S: Tb
(0.54 μm). However, a phosphor having many peaks with similar intensity, for example, LaOBr: Tb is 380n
m, 440 nm, and 451 nm, when there is a peak with similar intensity, the shortest wavelength is 380 nm (0.38 μm).
m). This is because if the average particle size of the phosphor is adjusted to the long wavelength peak, the transmittance of short wavelength light emission is likely to decrease,
This is because the effect may be reduced.

Generally, the emission wavelength of the radiation intensifying screen is about 300 to 700 nm, and the average particle diameter of the phosphor particles used in the present invention is 350 nm (0.35 μm).
m) is the upper limit.

The main emission wavelengths of the main phosphors are shown below.

CaWO ₄ 420 nm Gd ₂ O ₂ S: Tb 544 nm LaOBr: Tb 380 nm YTaO ₄ 338 nm It has been known that the sharpness of the average particle size of these phosphor particles is improved by reducing the particle size.
However, it has been found that when the particle size is made small, the scattering of the emitted light by the phosphor particles increases, so it becomes difficult for the light emitted from the layer close to the support of the phosphor layer to reach the surface of the phosphor layer, and the sensitivity decreases. There is.

However, when the phosphor particles are made into fine particles and the average particle diameter of the particles is set to 1/2 or less of the emission wavelength of the phosphor, the transmittance of the phosphor layer for light emission is improved, the scattered light is reduced, and the sensitivity is lowered. It was found that the image quality can be improved without dropping. That is, since light has a wave property, if the particles are sufficiently smaller than the wavelength, the light transmittance increases.

However, the average particle size of the phosphor particles is 0.01
When the thickness is less than μm, the surface area of the phosphor per unit volume increases, so that the phosphor is likely to be affected by factors such as lattice defects and impurities that are present on the surface of the phosphor. In addition, since the particles are small, the crystallization of the phosphor is incomplete, the presence state of the trace activator is likely to be nonuniform, and the emission brightness of the phosphor sharply decreases. Therefore, it cannot be used as a radiographic intensifying screen.

The emission intensity can be further improved by applying a phosphor having a high emission intensity and a large particle size of 0.05 to 0.35 μm to the layer close to the support.

The particle size of the phosphor particles is measured by exposing the cross section of the phosphor layer of the radiation intensifying screen using a microtome or the like, and then plasma low temperature ashing method (for example, Yamato Scientific Co., Ltd. PR-503 model) is used. ) Remove the binder on the surface of the phosphor to expose the particles. The treatment conditions are selected such that the binder is removed but the particles are not damaged. This is observed with a scanning electron microscope, the image of the particles is connected to an image processing device (for example, LA-555 manufactured by Pierce Co., Ltd.), the observation location is changed, and the processing of the following formula is performed when the number of particles is 3000 or more. The number average particle diameter D obtained by the above was used as the average particle diameter.

D = ΣDi / N Here, Di is the equivalent circular diameter of the particles, and N is the number.

The fine particle phosphor having a main emission wavelength of ½ or less, which is used in the radiation intensifying screen of the present invention, is difficult to disperse, so that the dispersibility of the phosphor is deteriorated and the sharpness,
Graininess is likely to decrease. Therefore, a thermoplastic elastomer is preferable as the binder for the phosphor. By controlling the molecular weight of the thermoplastic elastomer, the dispersibility of the phosphor can be improved, and the sharpness and graininess of the image can be improved. A large particle size phosphor is easily dispersible and is not easily affected by the molecular weight of the binder.

The binder of the phosphor used in the radiation intensifying screen of the present invention is preferably a thermoplastic elastomer having a weight average molecular weight of 3,000 or more and 70,000.
Below, the dispersibility of the fine particle phosphor can be improved in this case.

When the weight average molecular weight of the thermoplastic elastomer is 3,000 or less, the flexibility is poor, and bending marks and cracks are particularly generated during bending. The weight average particle amount is 70,
When it is 000 or more, the ductility is high and the dispersibility of the phosphor is lowered.

The molecular weight of the binder is as follows: Tosoh Corp. molecular weight measuring device GPC, HLC-8020, UV detector UV-8
010 (Auto-supplier AS-8000, data processing S
C-8010) and two columns of GMHXL (TH
(For F) and THF as a solvent at a flow rate of 1 ml /
min, inlet temp. 40 ° C, Ovente
mp. 40 ° C., RI temp. The temperature was set to 40 ° C., the test binder was dissolved in THF and adjusted to 0.5 (wt / vl)%. The measurement sample volume was 100 μl. It can be determined by converting the molecular weight of the sample binder into the molecular weight of polystyrene from a calibration curve prepared in advance with polystyrene of known molecular weight.

As the kind of the thermoplastic elastomer, polyurethane resin and polyester resin are preferable, and since these elastomers have a strong binding force with the phosphor, the dispersibility is good. In addition, it is also highly ductile and has good flexibility when used as a radiographic intensifying screen.

Examples of the binder used in the present invention include polyurethane resin, polyester resin, polystyrene resin, polyolefin resin, polyamide resin, polybutadiene resin, ethylene vinyl acetate resin, polyvinyl chloride resin, natural rubber, fluororubber, and polyresin. Examples thereof include isoprene resin, chlorinated polyethylene resin, styrene-butadiene rubber, cellulose resin and silicone rubber.

The mixing ratio of the binder used in the radiation intensifying screen of the present invention and the phosphor described below is 1: 1 to 1: 1.
It is preferably selected from the range of 100 (weight ratio), more preferably from the range of 1: 8 to 1:40 (weight ratio).

Preferred phosphors used in the radiographic intensifying screen of the present invention include those shown below.

Tungstate phosphor (CaWO ₄ ,
MgWO ₄ , CaWO ₄ : Pb, etc.), terbium-activated rare earth oxysulfide-based phosphor [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 phosphor (YPO ₄ : Tb, GdPO ₄ : T
b, LaPO ₄ : Tb, etc.), terbium-activated rare earth oxyhalide-based phosphor (LaOBr: Tb, LaOB)
r: Tb. Tm, LaOCl: Tb, LaOCl: T
b. Tm, LaOCl: Tb. Tm. LaOBr: Tb
GdOBr: Tb GdOCl: Tb), thulium-activated rare earth oxyhalide-based phosphor (LaOBr: T)
m, LaOCl: Tm, etc.), barium sulfate-based phosphor [B
aSO ₄ : Pb, BaSO ₄ : Eu ²⁺ , (Ba, Sr) S
O ₄ : Eu ^2+, etc.] Divalent eurobium-activated alkaline earth metal phosphate-based phosphor [(Ba ₂ PO ₄ ) ₂ : Eu ²⁺ ,
(Ba ₂ PO ₄ ) ₂ : Eu ^2+, etc.] Divalent europium-activated alkaline earth metal fluorohalide-based phosphor [BaF
Cl: Eu ²⁺ , BaFBr: Eu ²⁺ , BaFCl: Eu
²⁺ . Tb, BaFBr: Eu ²⁺ . Tb, BaF ₂ · Ba
Cl ・ KCl: Eu ²⁺ , (Ba ・ Mg) F ₂・ BaCl
KCl: Eu ^2+, etc.], iodide-based phosphor (CsI: N
a, CsI: Tl, NaI, KI: Tl, etc.), a sulfide-based phosphor [ZnS: Ag (Zn.Cd) S: Ag, (Z
n. Cd) S: Cu, (Zn.Cd) S: Cu. Al
Etc.], 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 : Nb,
[Y, Sr] TaO ₄ : Gd, Gd TaO ₄ : Tm, Gd
₂ O ₃ .Ta ₂ O ₅ .B ₂ O ₃ : Tb, etc., but the phosphors used in the present invention are not limited to these, and fluorescence that emits light in the visible or near-ultraviolet region upon irradiation with radiation. Any body can be used.

The first method of producing a radiation intensifying screen is to apply a phosphor coating solution (hereinafter referred to as phosphor coating material) comprising a binder and a phosphor onto a support to form a phosphor layer. To do.

As a second production method, a sheet made of a binder and a phosphor coating material made of a phosphor is formed, and the sheet is placed on a support, preferably the softening temperature or melting point of the binder. It is manufactured in the step of adhering to the support at the above temperature.

As a method for forming the phosphor layer on the support,
Although the above-mentioned two types are conceivable, any method may be used as long as it is a method for uniformly forming the phosphor layer on the support, and spraying or the like may be used.

The phosphor layer of the first manufacturing method can be manufactured by applying a phosphor coating material in which the phosphor is uniformly dispersed in a binder solution onto a support and then drying it.

The phosphor sheet to be the phosphor layer of the second manufacturing method is obtained by applying the phosphor coating on the phosphor sheet forming temporary support, drying it, and then peeling it from the temporary support. Can be manufactured.

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

Solvents for preparing the phosphor coating include lower alcohols such as methanol, ethanol, n-propanol and n-butanol, chlorine atom-containing hydrocarbons such as methylene chloride and ethylene chloride, acetone, methyl ethyl ketone and methyl isobutyl ketone. Ketones, aromatic compounds such as toluene and benzene, esters of lower fatty acids and lower alcohols such as methyl acetate, ethyl acetate and butyl acetate, ethers such as dioxane, ethylene glycol monoethyl ester and ethylene glycol monomethyl ester, and mixtures thereof. Can be mentioned.

In the phosphor coating material, a dispersant for improving the dispersibility of the phosphor in the coating material or a binding agent between the binder and the phosphor in the formed phosphor layer is used. Various additives such as plasticizers may be mixed.

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

Examples of plasticizers include triphenyl phosphate,
Phosphates such as tricresyl phosphate and diphenyl phosphate, diethyl phthalate, phthalates such as dimethoxyethyl phthalate, glycolates such as ethylphthalylethyl glycolate and butylphthalbutyl glycolate, triethylene glycol and adipic acid Examples thereof include polyesters, polyesters of polyethylene glycol such as diethylene glycol and succinic acid, and polyesters of aliphatic dibasic acid.

A coating film of the coating material is formed by uniformly coating the surface of a support or a temporary support for sheet formation with the phosphor coating containing the phosphor and the binder prepared as described above. To 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 temporary support, those made of various materials such as glass, wool, cotton, paper and metal can be used, but they are flexible in handling as an information recording material. What can be processed into a sheet or roll is preferable. 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, aluminum foil, metal sheet such as 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 No. 784,615, pigments such as titanium dioxide. Pigmented paper containing, or processed paper such as paper sized with polyvinyl alcohol is particularly preferable.

In the second manufacturing method, a phosphor coating is applied on a temporary support, dried, and then peeled from the temporary support to obtain a phosphor sheet to be a phosphor layer. Therefore, the surface of the temporary support is
It is preferable to apply a release agent in advance so that the formed phosphor sheet can be easily released from the temporary support.

In order to strengthen the bond between the support and the phosphor layer, a high molecular substance such as gelatin is applied to the surface of the support to provide an undercoat layer for imparting adhesiveness, sensitivity, image quality (sharpness, sharpness,
In order to improve (granularity), 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. Those configurations can be arbitrarily selected according to the purpose, application, etc.

Further, the phosphor layer of the present invention may be compressed. By compressing the phosphor layer, the packing density of the phosphor can be improved, and the sharpness and graininess can be further improved. Examples of the compression method include a press machine and a calendar roll.

In the case of the first manufacturing method, it is preferable to compress the phosphor and the support as they are. In the case of the second production method, the phosphor sheet obtained as described above may be placed on a support, and the phosphor sheet may be adhered to the support while being compressed at a softening temperature or a temperature equal to or higher than the melting point of the binder. .

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

Usually, in a radiographic intensifying screen, a transparent protective film for physically and chemically protecting the phosphor layer is provided on the surface of the phosphor layer on the side opposite to the side in contact with the support. To be It is preferable to install such a transparent protective film also in the present invention. The thickness of the protective film is generally 2 to
It is in the range of 20 μm.

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

Alternatively, a plastic sheet made of polyethylene terephthalate, polyethylene naphthalate, polyethylene, polyvinylidene chloride, polyamide or the like, and a protective film forming sheet such as a transparent glass plate are separately prepared and appropriately adhered to the surface of the phosphor layer. It can be formed by a method such as bonding using a chemical.

The protective film used in the present invention is preferably formed by a coating film containing a fluorine-based 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 film formed by the coating film of the fluorine-based resin may be crosslinked. The protective film made of fluorine-based resin does not easily get into the protective film due to contact with the tentacles or the photosensitive material such as fat and stains such as plasticizer from the photosensitive material. There are advantages.

Further, for the purpose of improving the film strength and the like, a fluorine-based resin may be mixed with another polymer substance.

The protective film is preferably a transparent synthetic resin layer having a thickness of 1 μm or more and 10 μm or less formed on the phosphor layer. By using such a thin protective film, especially in the case of a radiation intensifying screen, the distance from the phosphor to the silver halide emulsion becomes short, which contributes to the improvement of the sharpness of the obtained radiation image.

Next, the silver halide photographic light-sensitive material of the present invention will be described.

The silver halide grains used in the silver halide photographic light-sensitive material of the present invention are generally produced and used in the form of a silver halide emulsion containing the grains. Of the emulsions used in the silver halide photographic light-sensitive material of the present invention, the emulsion used in the emulsion layer closest to the support may be either silver bromide or silver iodobromide. Silver iodobromide is preferred from the standpoint that a sensitive product can be obtained. The silver halide grains in the photographic emulsion are all isotropically grown, such as cubes, octahedra and tetrahedra, or are polyhedral crystals such as spheres, twins having plane defects, It may be composed of tabular grains, or a mixed type or a composite type thereof. Regarding the halogen distribution in the grain, it may have a uniform structure or a layered structure (core / shell structure), and the silver iodide content is preferably 2 mol% or less.

The silver halide photographic light-sensitive material of the present invention has a silver halide emulsion layer containing silver halide grains in which the average projected area diameters of the silver halide grains contained differ by 1.2 times or more and are large. When the silver halide emulsion layer containing the other grain is on the side closer to the support of the light-sensitive material,
By using in combination with the radiation intensifying screen of the present invention, it becomes possible to improve the sensitivity and sharpness, which are the objects of the present invention. These silver halide grains are preferably tabular silver halide grains, and the smaller silver halide grain has an average projected area diameter of 0.3 to 0.6 μm with an aspect ratio of 2 to 6. It is particularly preferable that the larger silver halide grains have an average projected area diameter of 0.6 to 1.5 μm with an aspect ratio of 4 to 8.

The silver halide photographic emulsion which can be used in the present invention can be produced by a known method. Although any method such as an acidic method, a neutral method, or an ammonia method may be used, it is preferable to use a double jet method (simultaneous mixing method) as a method of reacting a soluble silver salt with a soluble halogen salt. As one form of the simultaneous mixing method, a method of keeping pAg in a liquid phase where silver halide is formed constant, that is, a so-called controlled double jet method can be used. According to this method, a silver halide emulsion having a regular crystal form and a substantially uniform grain size can be obtained. In determining the addition rate, reference can be made to JP-A-54-48521 and JP-A-58-49938.

In the silver halide photographic emulsion which can be used in the present invention, some or all of the steps during grain formation are grain formation steps by supplying fine silver iodide grains (hereinafter referred to as fine grains). May be. Since the particle size of the fine particles controls the supply rate of iodine ions, the preferred particle size depends on the size of the silver halide grains of the host and the halogen composition, but those having an average equivalent spherical diameter of 0.3 μm or less are used. It is more preferably 0.1 μm or less. In order for the fine particles to be laminated on the host particles by recrystallization, the particle size of the fine particles is preferably smaller than the equivalent spherical diameter of the host particles, and more preferably,
It is 1/10 or less of this equivalent spherical diameter. The halogen composition of the fine grains has a silver iodide content of 95 mol% or more, and is preferably pure silver iodide. The silver halide emulsion used in the practice of the present invention includes a Nudel water washing method, a flocculation sedimentation method, etc. in order to remove soluble salts to obtain a pAg ion concentration suitable for chemical sensitization after the growth of silver halide grains is completed. The preferred washing method is, for example, a method using an aromatic hydrocarbon aldehyde resin containing a sulfo group described in JP-B-35-16086, or a polymer flocculant described in JP-A-2-7037. Example G
A desalting method using -3, G-8 and the like can be mentioned.

In the silver halide emulsion according to the present invention, various hydrophilic colloids for wrapping silver halide are used as a binder. For this purpose, gelatin and other synthetic polymers such as polyvinyl alcohol and polyacrylamide, colloidal albumin,
Photographic binders such as polysaccharides and cellulose derivatives are used.

In the case of chemical sensitization, ordinary sulfur sensitization,
Reduction sensitization, precious metal sensitization and combinations thereof are used. More specific chemical sensitizers include sulfur sensitizers such as allylthiocarbamide, thiourea, thiosulfate, thioether and cystine; precious metal sensitizers such as potassium chloroaurate, aurath thiosulfate and potassium chloroparadate. Examples thereof include reduction sensitizers such as tin chloride, phenylhydrazine, and reductone.

The photographic emulsions used in the practice of this invention may be spectrally sensitized with cyanine dyes and the like. The sensitizing dyes may be used alone, or a combination thereof may be used, and the combination of the sensitizing dyes is often used particularly for the purpose of supersensitization.

In the photographic light-sensitive material of the present invention, various photographic additives can be used in the steps before and after physical ripening or chemical ripening of the emulsion. Examples of the compound that can be used in such a step include Research Disclosure (RD) 17643 and (RD) 18716 (197) described above.
And various compounds described in (RD) 308119 (December 1989).
The types and locations of the compounds described in these three (RD) are listed below.

Additive RD-17643 RD-18716 RD-308119 Page Classification Page Page Classification Chemical sensitizer 23 648 Upper right 996 Sensitizing dye 23 648-649 996-8 Desensitizing dye 23 998 B Dye 25-26 649-650 1003 Development accelerator 29 XXI 648 Upper right fogging inhibitor / stabilizer 24 649 Upper right 1006-7 Whitening agent 24 998 Hardener 26 651 Left 1004-5 Surfactant 26-27 XI 650 Right 1005-6 XI Plasticizer 27 XXI 650 right 1006 XXI slip agent 27 XXI matte agent 28 XVI 650 right 1008-9 XVI binder 26 XXII 1003-4 support 28 XVII 1009 XVII In the present invention, the film is hardened so that the swelling percentage is 200% or less. . Here, the swelling percentage is expressed by the following equation.

Swelling percentage = (layer thickness when immersed in distilled water−
(Initial layer thickness) / (initial layer thickness) × 100% Here, the initial layer thickness means the layer thickness of the photographic material that has been subjected to an incubation treatment for 16 hours at a relative humidity of 40 ° C. and 60% RH. Say. The thickness when immersed in distilled water refers to the thickness of the layer when this photographic material is immersed in distilled water at 21 ° C. for 3 minutes. The swelling ratio can be adjusted by the amount of the hardener in the silver halide photographic light-sensitive material, as is well known in the art.

Hardeners that can be used in the present invention include mucochloric acid, mucobromic acid, mucophenoxycycloric acid, mucophenoxybromic acid, formaldehyde, dimethylolurea, trimethylolmelamine, glyoxal, monomethylglyoxal, 2,3-dihydroxy. -1,4-dioxane, 2,3-dihydroxy-5-methyl-1,4-dioxane, succinaldehyde, 2,
Aldehyde compounds such as 5-dimethoxytetrahydrofuran and glutaraldehyde; divinyl sulfone, methylene bismaleimide, 5-acetyl-1,3-diacryloyl-hexahydro-s-triazine, 1,3,5-
Triacryloyl-hexahydro-s-triazine,
1,3,5-trivinylsulfonyl-hexahydro-s
-Triazine bis (vinylsulfonylmethyl) ether, 1,3-bis (vinylsulfonylmethyl) propanol-2, bis (α-vinylsulfonylacetamide)
Active vinyl compounds such as ethane; 2,4-dichloro-
6-hydroxy-s-triazine sodium salt, 2,
4-dichloro-6-methoxy-s-triazine, 2,4
-Dichloro-6- (4-sulfoanilino) -s-triazine sodium acid, 2,4-dichloro-6- (2-sulfoethylamino) -s-triazine, N, N'-bis (2-chloroethylcarba) Mil) active halogen compounds such as piperazine; bis (2,3-epoxypropyl)
Methylpropylammonium p-toluenesulfonate, 1,4-bis (2 ′, 3′-epoxypropyloxy) butane, 1,3,5-triglycidyl isocyanurate, 1,3-diglycidyl-5- (γ -Acetoxy-
Epoxy compounds such as β-oxypropyl) isocyanurate; 2,4,6-triethyleneimino-s-triazine, 1,6-hexamethylene-N, N′-bisethyleneurea, bis-β-ethyleneiminoethyl Ethyleneimine compounds such as thioethers; 1,2-di (methanesulfonoxy) ethane, 1,4-di (methanesulfonoxy) butane, 1,5-di (methanesulfonoxy)
Methanesulfonic acid ester-based compounds such as pentane; carbodiimide-based compounds; isoxazole-based compounds; inorganic-based compounds such as chrome meiban and U.S. Pat. Nos. 3,057,723, 3,396,029 and 4, Polymer hardeners such as those described in No. 161,407 can be mentioned. The amount of hardener depends on the type of hardener,
Since it varies depending on the drying conditions at the time of producing the light-sensitive material, it cannot be decided in any way, but it can be appropriately adjusted within the range of 0.05 to 100 mmol, especially 0.1 to 50 mmol of the hardening agent per 100 g of dried gelatin. it can.

Examples of the support used in the silver halide photographic light-sensitive material of the present invention include those described in RD above. Suitable supports include plastic films and the like, and the surface of the support is coated. An undercoat layer may be provided to improve the adhesiveness of the layer, or corona discharge or ultraviolet irradiation may be performed. Then, the emulsion according to the present invention can be coated on both sides of the support thus treated.

The silver halide photographic light-sensitive material of the present invention comprises
In addition, if necessary, an antihalation layer, an intermediate layer, a filter layer, etc. can be provided.

The processing of the light-sensitive material of the present invention is carried out, for example, by a processing solution as described in RD-17643, XX to XXI, pages 29 to 30 or 308119, XX to XXI, pages 1011 to 1012. May be done.

Developers for black and white photographic processing include dihydroxybenzenes (eg hydroquinone), 3-pyrazolidones (eg 1-phenyl-3-pyrazolidone), aminophenols (eg N-methyl-aminophenol) and the like. They can be used alone or in combination. It should be noted that, for example, known preservatives, alkali agents, pH buffers, antifoggants, hardeners, development accelerators, surfactants, defoamers, toning agents, water softeners, and dissolution aids are well known in the developer. Alternatively, a viscosity-imparting agent may be used if necessary.

A fixing agent such as thiosulfate or thiocyanate is used in the fixing solution and may further contain a water-soluble aluminum salt such as aluminum sulfate or potassium alum as a hardening agent. Other preservatives, pH adjusters,
It may contain a water softener and the like.

In the present invention, the total processing time (Dry to
It is possible to perform ultra-rapid processing with Dry) of 40 seconds or less. "Development step time" or "development time" in the present invention
Is the time from the immersion of the leading edge of the photosensitive material in the developing tank solution of the automatic developing machine (hereinafter referred to as "developing machine") to the next fixing solution, and the "fixing time" is the fixing tank. The time from the time of dipping in the liquid to the time of dipping in the next washing tank liquid (stabilizing liquid), "washing time" means the time of dipping in the washing tank liquid. Further, the "drying time" usually means that the automatic developing machine is provided with a drying zone in which hot air of 35 to 100 ° C., preferably 40 to 80 ° C. is blown, and the time of entering the drying zone. . In the development processing of the present invention, the development time is 10 seconds or less, preferably 3 seconds to 10 seconds,
The developing temperature is preferably 25 to 50 ° C, more preferably 30 to 40 ° C. Fixing temperature and time is 20 to 50 ° C for 2 seconds to
It is preferably 12 seconds, more preferably 2 seconds to 10 seconds at 30 to 40 ° C. Washing or stabilizing bath temperature and time is 0-50 ° C
2 to 15 seconds is preferable, and 15 to 40 ° C. is more preferably 2 to 8 seconds. According to the method of the present invention, the developed, fixed and washed (or stabilized) photographic material is dried through a squeeze roller which squeezes the washing water. 40 to dry
It is carried out at 100 ° C., and the drying time may be appropriately changed depending on the environmental temperature, but is usually 3 seconds to 12 seconds, particularly preferably 40 ° C. to 80 ° C. and 3 seconds to 8 seconds. It is more preferable to use a far infrared heater.

In the present invention, processing can be performed with a developing time of 10 seconds or less and a developer replenishing amount of 200 ml or less per 1 m ^{2 of the} silver halide photographic light-sensitive material.

In the photographic light-sensitive material of the present invention, the photographic emulsion layer and other hydrophilic colloid layers can be coated on the support or other layers by various coating methods. For coating, a dip coating method, a roller coating method, a curtain coating method, an extrusion coating method, a slide hopper method, or the like can be used. For more information, Research Disclosure, No. 17
Volume 6, P. 27-28 "Coating process
The method described in the section "dures" can be used.

In addition, in implementing the present invention, various techniques used in the photographic technique can be applied.

[0078]

EXAMPLES Examples of the present invention will be described below. Naturally, the present invention is not limited to the examples described below.

Example 1 (Preparation of radiation intensifying screen) Formulation of coating material for fluorescent layer (unit is parts by weight) Gd ₂ O ₂ S: Tb (average particle size shown in Table 1) 200 Polyurethane resin (shown in Table 1) Molecular weight) 10 Nitrocellulose 2 In the above formulation, the coating composition has a viscosity of 20 to 20 using the phosphor having the particle diameter shown in Table 1 and the polyurethane resin shown in Table 1 as a binder.
Methyl ethyl ketone was added to give 30 ps (poise). The mixture was mixed and dispersed in a ball mill for 6 hours to obtain phosphor coating materials a to h. Next, the above-mentioned phosphor coating was applied on a polyethylene terephthalate support in which titanium dioxide having a thickness of 250 μm was set horizontally on a glass plate so that the film constitution and weight ratio shown in Table 4 were obtained when dried. After drying to form a phosphor layer, a transparent polyethylene terephthalate sheet having a thickness of 8 μm and coated with a polyester adhesive on one surface is provided with a protective layer by adhering the adhesive surface to the fluorescent layer surface. The radiographic intensifying screen shown was obtained. 2 parts by weight of isocyanate was added to and mixed with the fluorescent paint immediately before coating.

(Preparation of monodisperse cubic seed emulsion EM-A) <Solution A> Ocein gelatin 30 g KBr 1.25 g Nitric acid (0.1 N) 150 ml Distilled water to 7700 ml <Solution B> KBr 6 g KI 0. 16g Distilled water to 740ml <Solution C> KBr 680g KI 20g Distilled water to 2480ml <Solution D> Silver nitrate 8.4g Nitric acid (0.1N) 32ml Distilled water to 740ml <Solution E> Silver nitrate 991.6g Nitric acid (0.1 N) 80 ml Solution B and solution D were added over 10 minutes to solution A, which was vigorously stirred at 60 ° C. with distilled water to 2480 ml, over 10 minutes. Then, the solution C and the solution E were added by the double jet method over 140 minutes. At this time, the initial addition flow rate was 1/8 of the final addition flow rate and was linearly increased with time. PH = 2, pAg = 8 while adding these liquids
Adjusted to a constant value. After addition is complete, pH is adjusted with sodium carbonate
Was increased to 6 and 150 g of KBr was added, followed by immediate desalting and washing with water to obtain a monodispersed cubic crystal seed emulsion EM-A of silver iodobromide containing 2 mol% of silver iodide having an average grain size of 0.3 μm. Obtained. According to the electron microscope observation, the occurrence rate of twins is 1 in number.
% Or less.

(Preparation of Normal Crystal Core / Shell Emulsion C) A normal crystal emulsion C containing 2.0 mol% AgI was prepared using the following 5 kinds of solutions.

[0082] <solution A> ossein gelatin _{75.5g HO- (CH 2 CH 2 O} ) n - [CH (CH 3) CH 2 O] 17 - (CH 2 CH 2 O) m H (n + m = 5. 7) 15% 10% aqueous methanol solution Equivalent to 0.928 mol of seed emulsion EM-A Make up to 4000 ml with distilled water.

<Solution B> Silver nitrate 151.3 g Ammonia solution equivalent to silver nitrate and distilled water were added to obtain 848 g.
Set to ml.

<Solution C> Silver nitrate 890.9 g Ammonia solution equivalent to silver nitrate and distilled water were added to obtain 149
Make up to 7 ml.

[0085] <Solution D>   KBr 74.1g   KI 44.3g Make up to 848 ml with distilled water.

[0086] <Solution E>   KBr 623.6g Make up to 1497 ml with distilled water.

The solution A was kept at 40 ° C. in the reaction vessel, and ammonia water and acetic acid were further added to adjust the pH to 9.5.

PAg was adjusted to 7. with an ammoniacal silver ion solution.
After adjusting to 3, the solution B and the solution D were added by the double jet method while keeping the pH and pAg constant to form a silver iodobromide layer containing 30 mol% of silver iodide.

PH was adjusted to 9.0 with acetic acid and KBr.
After adjusting g to 9.0, solution C and solution E were added at the same time and grown, and then grown to reach 90% of the final particle size.
At this time, the pH was gradually lowered from 9.0 to 8.20.

After adding KBr solution to adjust pAg to 11, solution C and solution E were further added to grow while gradually lowering the pH to 8 to obtain a silver iodobromide emulsion containing 2 mol% of silver iodide.

After completion of the addition, the following sensitizing dyes (A) and (B) were added, and then, in order to remove excess salts, precipitation desalting was performed using an aqueous solution of demole (manufactured by Kao Atlas Co.) and an aqueous solution of magnesium sulfate. Done, ossein gelatin 9
An aqueous gelatin solution containing 2.2 g was added to make 2500 ml, and the mixture was stirred and redispersed to prepare an emulsion c.

Sensitizing dye (A): 5,5'-dichloro-9
-Ethyl-3,3'-di- (3-sulfopropyl) oxacarbocyanine salt anhydride sensitizing dye (B): 5,5'-di- (butoxycarbonyl) -1,1'-diethyl-3, 3'-Di- (4-sulfobutyl) benzimidazolocarbocyanine sodium salt anhydrous About 3000 particles of the obtained emulsion C were observed and measured by an electron microscope to analyze the shape, and the average particle diameter was 0.
The particles were monodisperse spherical particles having a width of 8 μm and a distribution of 12%.

(Preparation of Hexagonal Tabular Seed Emulsion EM-B) A hexagonal tabular seed emulsion was prepared by the following method.

[0094] <solution A> ossein gelatin 60.2g Distilled water _{20.0l HO- (CH 2 CH 2 O} ) n - [CH (CH 3) CH 2 O] 17 - (CH 2 CH 2 O) m H (N + m = 5.7) 10% aqueous methanol solution 5.6 ml KBr 26.8 g 10% H ₂ SO ₄ 144 ml <Solution B> Silver nitrate 1487.5 g Distilled water to 3500 ml <Solution C> KBr 1029 g KI 29.3 g Distillation Make up to 3500 ml with water <Solution D> 1.75N KBr aqueous solution At the following silver potential control amount of 35 ° C, JP-B-58-58288 and 58-58-
Using the mixing stirrer shown in No. 58289, 64.1 ml of each of solution B and solution C was added to solution A by the simultaneous mixing method for 2 minutes to perform nucleation.

After stopping the addition of Solution B and Solution C, 6
Take 0 minutes to raise the temperature of solution A to 60 ° C.,
The solution B and the solution C were again mixed by the simultaneous mixing method to obtain 68.5 each.
It was added at a flow rate of ml / min for 50 minutes. During this period, the silver potential (measured with a silver ion selective electrode using a saturated silver-silver chloride electrode as a reference electrode) was controlled to be +6 mV using the solution D. After the addition was completed, the pH was adjusted to 6 with 3% KOH, and the mixture was immediately desalted and washed with water to obtain a seed emulsion EM-B. In the seed emulsion EM-B thus prepared, 90% or more of the total projected area of silver halide grains has a maximum adjacent side ratio of 1.0 to
2.0 hexagonal tabular grains, the hexagonal tabular plate has an average thickness of 0.07 μm, and an average diameter (circular diameter conversion) of 0.5 μm.
It was found by electron microscope observation that the coefficient of variation was 25%.

(Preparation of Twin Crystal Emulsion A) Monodispersed twin silver iodobromide emulsion B containing 1.53 mol% AgI was prepared using the following four kinds of solutions.

[0097] <solution A> ossein gelatin _{29.4g HO- (CH 2 CH 2 O} ) n - [CH (CH 3) CH 2 O] 17 - (CH 2 CH 2 O) m H (n + m = 5. 7) 10% aqueous methanol solution 2.5 ml seed emulsion EM-B 0.588 mol equivalent 4800 ml with distilled water <Solution B> Silver nitrate 1404.2 g Distilled water with 2360 ml <Solution C> KBr 968 g KI 20.6 g Distillation Make up to 2360 ml with water <Solution D> 1.75N KBr aqueous solution At the following silver potential control amount of 60 ° C, Japanese Patent Publication Nos. 58-58288 and 58-58288.
Using a mixing stirrer shown in No. 58289, the total amount of Solution B and Solution C was adjusted to 21.26 by the simultaneous mixing method.
Addition growth was performed for 111 minutes at a flow rate of ml / min. During this period, the silver potential was controlled to be +25 mV by using the solution D.

After the addition was completed, the sensitizing dyes (A) and (B) were added in an amount of 300 mg and 15 mg, respectively, per mol of silver halide.
After the addition, in order to remove excess salts, precipitation desalting was carried out using an aqueous solution of demole (manufactured by Kao Atlas) and an aqueous solution of magnesium sulfate, and an aqueous gelatin solution containing 92.2 g of ossein gelatin was added to 2500 ml, followed by stirring again. Dispersed.

Approximately 3000 grains of the silver halide emulsion B were observed and measured by an electron microscope to analyze the shape,
It was a tabular grain having an average grain diameter of 0.4 μm and an aspect ratio of 3.0.

In the method for preparing the silver halide emulsion a,
By changing the addition amounts and addition rates of EM-B, solutions B, C, and D, silver halide emulsions (a) to (c) having a grain size and an aspect ratio shown in Table 2 were obtained.

(Preparation of Sample) Various additives described below were added to each emulsion to prepare emulsion coating solutions. The addition amount is indicated by the amount per mol of silver halide.

T-Butyl-catechol 400 mg Polyvinylpyrrolidone (molecular weight 10.000) 1.0 g Styrene maleic anhydride copolymer 2.5 g Trimethylolpropane 10 g Diethylene glycol 5.0 g Nitrophenyl-triphenylphosphonium chloride 50 mg 1,3- sodium ammonium dihydroxybenzene-4-sulfonic acid 4.0 g 2-mercaptobenzimidazole indazole-5-sulfonic acid _{1.5mg n-C 4 H 9 OCH} 2 CH (OH) CH 2 n (CH 2 COOH) 2 1.0g

[0103]

[Chemical 1]

The following were prepared as a protective layer solution or a protective layer coating solution. The added amount is shown as an amount per 1 g of gelatin.

[0105]   Matting agent made of polymethylmethacrylate (area average particle size 7 μm)                                                           7.0 mg   Colloidal silica (average particle size 0.013 μm) 70 mg   2,4-Dichloro-6-hydroxy-1,3,5-triazine sodium                                                             30 mg   Sodium-i-amyl-n-decyl-sulfosuccinate 7.0 mg

[0106]

[Chemical 2]

A crossover cut layer containing, as a crossover cut substance, the amount of the dye shown below in Table 3 as a solid dispersion is applied between the silver halide emulsion layer and the undercoat layer. did.

[0108]

[Chemical 3]

(Method of adding as solid disperse dye) The above dye is dispersed in solid fine particles by a ball mill according to the following procedure.

That is, water and a surfactant alkanol XC (alkylnaphthalene sulfonate [manufactured by DuPont]) were placed in a ball mill container, a dye to be added thereto was added, zirconium oxide beads were placed therein, and the container was sealed and dispersed in a ball mill for 4 days. To do. Then, add the gelatin aqueous solution to 1
After mixing for 0 minutes, the beads were removed to obtain a coating solution.

The above coating solution was applied onto a blue-colored polyethylene terephthalate film base having a thickness of 175 μm, which had been subjected to an undercoating treatment, with the constitution shown in Table 3 on the support side (lower layer) silver halide emulsion and the protective layer side (upper layer). ) Light-sensitive materials 1 to 6 were prepared by uniformly coating both surfaces of a silver halide emulsion and a protective layer and drying. In this case, a grain-amount per one side lower 1.6 g / m ^2, the upper layer 0.5 g / m ^2, the amount of gelatin per one side, the lower layer 1.4 g / m ^2, the upper layer 0.3 g /
m ² and the protective layer were adjusted to 0.9 g / m ² .

Photosensitive materials 1 to 6 obtained as described above
And a radiation intensifying screen was combined as shown in Table 4 to evaluate the sharpness and the sensitivity. The sensitivity is sample N
o. 1 was set as 100 and displayed with relative sensitivity. The development processing conditions are CEPROS30 (Fuji Photo Film Co., Ltd.).
Was manufactured in the SP mode. The sharpness was evaluated by a standard method using a rectangular wave chart.

The results are shown in Table 4.

[0114]

[Table 1]

[0115]

[Table 2]

[0116]

[Table 3]

[0117]

[Table 4]

As is clear from Table 4, the radiation intensifying screen of the present invention having a phosphor layer containing phosphor particles having an average particle diameter of 0.01 μm or more and ½ or less of the main emission wavelength of the phosphor. No. Nos. 10 to 21 and 25 to 28 are clearly superior to the comparative sample in terms of sharpness and sensitivity. Further, among them, it can be seen that the materials using 2, 4 as the light-sensitive material are particularly excellent.

Example 2 The radiation intensifying screen shown in Table 5 was prepared by changing the phosphor Gd ₂ O ₂ S: Tb of Example 1 to CaWO ₄ and dispersing and coating it in a polyurethane resin having a molecular weight of 80,000. The same evaluation was performed using the photosensitive material 4.

[0120]

[Table 5]

As can be seen from Table 5, the sharpness and sensitivity of the sample having a small particle size arranged on the side far from the support with 0.210 μm, which is 1/2 of the emission wavelength of the phosphor, as the boundary. It turns out to be excellent.

[0122]

By using the radiation intensifying screen of the present invention and the silver halide photographic material in combination, an image having excellent sharpness can be obtained without lowering the sensitivity.

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Claims (2)

(57) [Claims] 1. An image forming method for exposing a silver halide photographic light-sensitive material with X-rays using a radiation intensifying screen, wherein the radiation intensifying screen has two or more phosphor layers, and In the phosphor layer farthest from the support,
0.01 μm or more and 1 of the main emission wavelength of the phosphor
The silver halide photographic light-sensitive material contains phosphor particles having a particle size of ½ or less, and the average projected area diameter of the silver halide particles contained is different by 1.2 times or more. A method of forming an image of a silver halide photographic light-sensitive material, characterized in that, of the silver halide emulsion layers, the silver halide emulsion layer containing silver halide grains having a large grain size is on the side closer to the support. 2. At least one of said silver halide emulsion layers
The layer has an average projected area diameter of 0.3 to 6 with an aspect ratio of 2 to 6.
0.6 μm, and at least one layer has an aspect ratio of 4 to
8. The method for forming an image of a silver halide photographic light-sensitive material according to claim 1, which is an emulsion layer containing silver halide grains having an average projected area diameter of 0.6 to 1.5 .mu.m.