JP2002023299A - Method for preparing organic silver salt dispersion, heat developing photosensitive material, image recording method using the same and image-forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for uniformly preparing an organic silver salt dispersion used in a heat developing photosensitive material, a heat developing photosensitive material having high sensitivity and good raw stock preservability, an image-recording method using the photosensitive material and an image-forming method. SOLUTION: In the method for preparing an organic silver salt dispersion, in which an aqueous nitric acid solution is added to an aqueous solution or suspension of an alkali salt of an organic acid, photosensitive silver halide grains are added, a water-soluble silver salt is further added and they are reacted in a reactor, an emulsion containing the photosensitive silver halide grains is added to the reactor, after ultrafiltration.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an organic silver salt dispersion, a photothermographic material, an image recording method using the same, and an image forming method.

[0002]

2. Description of the Related Art Conventionally, in the field of printing plate making and medical treatment, waste liquids caused by wet processing of image forming materials have been a problem in terms of workability. There is a strong demand for weight loss. Therefore, there has been a need for a technique relating to photothermographic materials for photographic technology, which enables efficient exposure with a laser imagesetter or laser imager and can form a high-resolution, clear black image.

As a technique for this, a heat-developable photographic light-sensitive material for forming a photographic image using a heat-development processing method is disclosed in, for example, US Pat. Nos. 3,152,904 and 3,457,07.
No. 5 and D.C. Morgan and B.A. Shelly Processed Sil by Shelly
ver Systems) "(Imaging Pr. and Materials (Imaging Pr.)
processes and Materials) Neb
lette 8th edition, Sturge, V.L.
Walworth, A .; Shepp, page 2, 1969).

Various methods are known for preparing an organic silver salt as a silver supplier used in a photothermographic material.
For example, JP-A-49-93310 and JP-A-49-9461.
No. 9, No. 53-68702, and a method for preparing an organic silver salt in a coexisting liquid of water and a poorly water-soluble solvent.
A method for preparing an organic silver salt in an organic solvent as described in JP-A-7-186745, JP-A-47-9432 and U.S. Pat. No. 3,700,458, JP-A-53-31611 and JP-A-54-4117. And methods for preparing an organic silver salt in an aqueous solution, as described in US Pat. No. 5,434,043.

On the other hand, in order to impart photosensitivity to the photothermographic material, a method of incorporating silver halide into the photothermographic material is widely known. This silver halide is commonly used for aqueous silver halide. It is advantageous to use those prepared based on the gelatin emulsion method from the viewpoint of easy introduction of techniques such as size control, crystal wall control, impurity doping, and chemical ripening.

However, when preparing an organic silver salt in the presence of an organic solvent or preparing an organic silver salt in an organic solvent, the silver halide rendered hydrophilic by such gelatin is uniformly dispersed in the organic silver salt. It is difficult to disperse, and it is very difficult to obtain a desired Dmax and sensitivity in photographic characteristics.

Accordingly, a method is generally employed in which silver halide is added at the stage of preparing an organic silver salt in an aqueous solution.
In this sense, the organic silver salt is advantageously prepared in an aqueous solution. As a method of preparing an organic silver salt dispersion in an aqueous solution, an organic fatty acid is dissolved in water at a temperature equal to or higher than its melting point, and reacted with an alkali hydroxide, and then, when the temperature is lowered, an emulsion is added. Is known to form an organic silver salt dispersion.

However, when the temperature is lowered after the addition of the alkali hydroxide, the viscosity of the dispersion increases sharply, and when the water-soluble silver salt is added, the viscosity further increases, so that the uniformity of the dispersion at that time is maintained. There was a problem that the organic silver particles formed were non-uniform, the sensitivity was lowered, and the raw storability of the photothermographic material was not yet sufficient. Therefore, there has been a demand for a solution to the above problems.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for uniformly producing an organic silver salt dispersion used for a photothermographic material, a photothermographic material having high sensitivity and good raw preservability. An object of the present invention is to provide an image recording method and an image forming method using the same.

[0010]

The above objects of the present invention have been attained by the following items 1 to 7.

1. After adding an aqueous solution of nitric acid to an aqueous solution or suspension of an alkali salt of an organic acid, photosensitive silver halide grains are added, and a water-soluble silver salt is further added and reacted in a reaction vessel to form an organic silver salt dispersion. A method for producing an organic silver salt dispersion, wherein the emulsion containing the photosensitive silver halide grains is subjected to ultrafiltration treatment and then added to the reaction vessel.

2. 2. The method for producing an organic silver salt dispersion as described in 1 above, wherein the photosensitive silver halide particles are monodispersed.

3. The organic silver salt dispersion is formed by a device in which stirring A along the inner wall or the bottom of the reaction layer and stirring B by a high-speed stirring member rotating at a high speed are simultaneously performed in the reaction layer. A method for producing an organic silver salt dispersion.

4. In a photothermographic material having a photosensitive layer containing a photosensitive silver halide, an organic silver salt, a reducing agent and a binder on a support, and a photothermographic material having a protective layer, a dispersion of the organic silver salt may be any of the above-described 1 to 3. A photothermographic material produced by the production method according to claim 1.

[0015] 5. 5. An image recording method, wherein the exposure is performed by an exposure device in which an angle between an exposure surface of the photothermographic material and the scanning laser beam does not become substantially perpendicular.

6. 5. An image forming method, wherein the photothermographic material according to 4 is heat-developed in a state where the photothermographic material contains a solvent in an amount of 5 to 1000 mg / m < ² >.

[7] 5. An image forming method, wherein the protective layer of the photothermographic material according to the item 4 is brought into contact with a heated drum to perform development.

Hereinafter, the present invention will be described in more detail. The method for producing the organic silver salt dispersion of the invention will be described.

According to the method for producing an organic silver salt dispersion of the present invention, an organic fatty acid is dissolved in water at a temperature equal to or higher than its melting point in a reaction vessel and then reacted with an alkali hydroxide to prepare an alkali metal salt of an organic acid. Thereafter, a step of lowering the temperature, adding a photosensitive silver halide emulsion subjected to ultrafiltration treatment, and further adding a water-soluble silver salt to form an organic silver salt dispersion is provided.

The present inventors differ from the conventionally known methods for producing organic silver salt dispersions by adding an ultrafiltered photosensitive silver halide emulsion to an alkali metal salt solution of an organic acid. As a result, it has been found that a photothermographic material produced using the same has high sensitivity and good raw storability.

The reason why the above-mentioned effect was obtained is not surprising, but the removal of low-molecular-weight gelatin present in conventional photosensitive silver halide emulsions has led to an increase in photosensitive silver halide grains. Dye (photosensitive dye) adsorption increases,
We believe that the unexpected effect of achieving high sensitivity and improving raw preservability at the same time was obtained.

An example of the ultrafiltration process according to the present invention will be described with reference to FIG. A photosensitive silver halide emulsion and an appropriate amount of water are put into a stirring vessel 11 and stirred by a stirring blade 12. While stirring, the mixture of the photosensitive emulsion and water is sent from the branch valve to the ultrafiltration unit 13 having the ultrafiltration membrane through the liquid feed pump 14 and the flow meter 18, and again through the diaphragm valve 15. Repeat the operation of returning to.
At this time, an appropriate flow rate is adjusted by the pressure gauge (entrance side) 17 and the pressure gauge (outside side) 16. In this manner, low molecular weight gelatin and the like contained in the photosensitive silver halide emulsion before ultrafiltration can be separated.

As the separation membrane used in the ultrafiltration according to the present invention, various known forms can be used. Separation membranes are generally classified into reverse osmosis membranes, ultrafiltration membranes, microfiltration membranes, etc., depending on the separation characteristics, and the separation membrane shapes are generally flat membrane type, spiral type, hollow fiber type, circular tube type, etc. It is classified. In the present invention, it is preferable to use a hollow fiber type membrane for fractionation of 300,000 or more. The separation membrane used in the present invention can be provided in a reaction vessel in various known forms. In the present invention, a mode in which a membrane separation device having a separation membrane is provided in an external circulation path connected to the addition vessel is most preferable.

In the present invention, the photosensitive silver halide emulsion subjected to the ultrafiltration treatment is added. The time from the ultrafiltration treatment to the start of addition to the reaction tank is 10 minutes. Is preferably within 5 minutes, particularly preferably within 2 minutes. The reason for this is that if the time from the ultrafiltration treatment to the addition to the reaction tank is unnecessarily long, problems over time such as the progress of Ostwald ripening of the photosensitive silver halide grains are likely to occur. It is presumed to be.

The photosensitive silver halide according to the present invention functions as an optical sensor. In the present invention, in order to suppress white turbidity after image formation and to obtain good image quality, the average grain size of the photosensitive silver halide grains is preferably small, and the average grain size is preferably 0.1 μm or less, more preferably. Is from 0.01 μm to 0.1 μm, particularly from 0.02 μm
0.08 μm is preferred. The particle size here means
Refers to the diameter (equivalent circle diameter) of a circle having an area equal to that of an individual particle image observed with an electron microscope. Further, the silver halide is preferably monodispersed. The monodispersion here is
The degree of monodispersion determined by the following formula is 40 or less. The particle size is more preferably 30 or less, and particularly preferably 20% or less.

Monodispersity = (standard deviation of particle size) / (average value of particle size) × 100 The shape of silver halide grains is not particularly limited, but the proportion occupied by the Miller index [100] plane is high. It is preferable that this ratio is 50% or more, further 70% or more,
In particular, it is preferably at least 80%. Miller index [1
The ratio of the [00] plane is determined by utilizing the dependence of the adsorption of the sensitizing dye on the [111] plane and the [100] plane. Tan
i. Imaging Sci. , 29, 165 (1
985).

Another preferred form of silver halide is tabular grains. The term "tabular grain" as used herein means a vertical thickness h μm where the square root of the projected area is a particle size r μm.
Means that the aspect ratio = r / h is 3 or more. Among them, the aspect ratio is preferably 3 or more and 50 or less. The particle size is preferably 0.1 μm or less, more preferably 0.01 μm to 0.08 μm.
These are disclosed in U.S. Pat.
Nos. 14,798 and 5,320,958, and it is possible to easily obtain target tabular grains.

The halogen composition is not particularly limited, and may be any of silver chloride, silver chlorobromide, silver chloroiodobromide, silver bromide, silver iodobromide and silver iodide. The photographic emulsion used in the present invention is P.I. Chimie et by Glafkids
Physique Photographique (P
aul Montel, 1967); F. D
Photographic Emuls by uffin
ion Chemistry (The Focal P
Res., 1966); L. Zelikman
Making and Coating by et al
Photographic Emulsion (Th
e Focal Press, 1964) and the like. That is, any of an acidic method, a neutral method, an ammonia method, etc. may be used,
The formation of reacting the soluble silver salt with the soluble halogen salt may be performed by any one of a one-side mixing method, a simultaneous mixing method, and a combination thereof.

The silver halide used in the present invention preferably contains metal ions belonging to groups 6 to 11 of the periodic table. As the above metals, W, Fe, Co,
Ni, Cu, Ru, Rh, Pd, Re, Os, Ir, P
t and Au are preferred.

These metal ions can be introduced into silver halide in the form of a metal complex or a metal complex ion. As these metal complexes or metal complex ions, hexacoordinate metal complexes represented by the following general formula are preferable.

In the formula [ML ₆ ] ^m , M is a transition metal selected from elements of Groups 6 to 11 of the periodic table, L is a ligand, and m is 0,-, 2-, 3- or 4-
Represents Specific examples of the ligand represented by L include halides (fluoride, chloride, bromide and iodide), cyanide, cyanate, thiocyanate, selenocyanate, tellurocyanate, azide and aquo. Ligand, nitrosyl, thionitrosyl and the like, preferably aquo, nitrosyl and thionitrosyl. If an aquo ligand is present, it preferably occupies one or two of the ligands. L may be the same or different.

Particularly preferred examples of M are rhodium (Rh), ruthenium (Ru), rhenium (Re), iridium (Ir) and osmium (Os).

Hereinafter, specific examples of transition metal complex ions will be shown, but the present invention is not limited to these.

[0034] 1: [RhCl _6] ^3- 2: [RuCl _6] ^3- 3: [ReCl _6] ^3- 4: [RuBr _6] ^3- 5: [OsCl _6] ^3- 6: [IrCl _6] ^{4 -} 7: [Ru (NO) Cl _5] ^2- 8: [RuBr ₄ (H ₂ O)] ^2- 9: _{[Ru (NO) (H 2 O} ) Cl 4 ] ^- 10: [RhCl ₅ (H ₂ O)] ^2-11 : [Re (NO) Cl ₅ ] ^2-12 : [Re (NO) (CN) ₅ ] ^2-13 : [Re (NO) Cl (CN) ₄ ] ^2-14 : [Rh (NO) ₂ Cl _4] ^- 15: _{[Rh (NO) (H 2 O} ) Cl 4 ] ^- 16: [Ru (NO) (CN) _5] ^2- 17: [Fe (CN) _6] ^3- 18 : [Rh (NS) Cl _5] ^2- 19: [Os (NO) Cl _5] ^2- 20: [Cr (NO) Cl _5] ^2- 21: [Re (NO) Cl _5] ^- 22: [Os (NS) Cl ₄ (TeCN)] ^{2 -} 23: [Ru (NS) Cl _5] ^2- 24: _{[Re (NS) Cl 4 (SeCN} ) ] ^2- 25: [Os (NS) Cl (SCN) 4 ] ^2- 26: [Ir (NO) Cl ₅ ] ^2-27 : [Ir (NS) Cl ₅ ] ^2- These metal ions, metal complexes or metal complex ions may be used alone or in combination of two or more of the same and different metals. Good. The content of these metal ions, metal complexes or metal complex ions, generally is suitably 1 × 10 ^-9 ~1 × 10 ^-2 mol per mol of silver halide, preferably 1 × 10 ^{- It is 8} to 1 × 10 ^-4 mol.

The compounds providing these metals are preferably added during silver halide grain formation and incorporated into silver halide grains. Preparation of silver halide grains, that is, nucleation, growth, physical ripening, and chemical ripening are carried out. Although it may be added at any stage before and after sensitization, it is particularly preferable to add at the stage of nucleation, growth and physical ripening, more preferably at the stage of nucleation and growth, and most preferably. It is added at the stage of nucleation.

In the addition, it may be added several times in several portions, may be added uniformly in the silver halide grains, or may be added to silver halide grains.
-306236, 3-167545, 4-76
No. 534, No. 6-110146, No. 5-273683
As described in Japanese Patent Application Laid-Open No. H10-284, etc., the particles can be contained in the particles with a distribution. Preferably, a distribution can be provided inside the particles.

These metal compounds can be added by dissolving them in water or a suitable organic solvent (eg, alcohols, ethers, glycols, ketones, esters, amides). A method in which an aqueous solution of a powder or an aqueous solution in which a metal compound and NaCl and KCl are dissolved together is added to a water-soluble silver salt solution or a water-soluble halide solution during grain formation, or a silver salt solution and a halide solution are used. When they are mixed simultaneously, they are added as a third aqueous solution to prepare silver halide grains by a three-liquid simultaneous mixing method, a method in which a required amount of an aqueous solution of a metal compound is charged into a reaction vessel during grain formation, or a method in which halogen is added. There is a method in which another silver halide grain doped with metal ions or complex ions in advance during the preparation of silver halide is added and dissolved.

In particular, a method of adding an aqueous solution of a powder of a metal compound or an aqueous solution in which a metal compound and NaCl and KCl are dissolved together is added to a water-soluble halide solution.

At the time of addition to the surface of the particles, a required amount of an aqueous solution of a metal compound can be charged into the reaction vessel immediately after the formation of the particles, during or at the end of physical ripening, or at the time of chemical ripening.

In the present invention, the photosensitive silver halide grains may or may not be desalted after grain formation. However, when desalting is performed, it is known in the art such as a noodle method and a flocculation method. Can be desalted by washing with water.

The photosensitive silver halide grains used in the present invention are preferably chemically sensitized. As a preferred chemical sensitization method, a sulfur sensitization method, a selenium sensitization method, and a tellurium sensitization method are well known in the art. In addition, a noble metal sensitization method or a reduction sensitization method of a gold compound, platinum, palladium, iridium compound or the like can be applied.

As the compounds preferably used in the sulfur sensitization method, selenium sensitization method, and tellurium sensitization method, known compounds can be used, and compounds described in JP-A-7-128768 and the like can be used. it can. Examples of tellurium sensitizers include diacyl tellurides, bis (oxycarbonyl) tellurides, bis (carbamoyl) tellurides, diacyl tellurides, bis (oxycarbonyl) ditellurides, bis (carbamoyl) ditellurides, and P = Te Compounds having a bond, tellurocarboxylates, Te-organyltellurocarboxylates, di (poly) tellurides, tellurides, tellurols, telluroacetals, tellurosulfonates, compounds having a P-Te bond, Te heterocycles, tellurocarbonyl compounds, inorganic tellurium compounds, colloidal tellurium, and the like can be used.

Compounds preferably used in the noble metal sensitization method include, for example, chloroauric acid, potassium chloroaurate,
Potassium aurithiocyanate, gold sulfide, gold selenide, or compounds described in U.S. Pat. No. 2,448,060 and British Patent No. 618,061 can be preferably used.

Specific compounds used in the reduction sensitization method include ascorbic acid and thiourea dioxide in addition to, for example,
Stannous chloride, aminoiminomethanesulfinic acid, hydrazine derivatives, borane compounds, silane compounds, polyamine compounds and the like can be used. Further, reduction sensitization can be achieved by ripening the emulsion while maintaining the pH of the emulsion at 7 or more or the pAg at 8.3 or less. Further, reduction sensitization can be achieved by introducing a single addition portion of silver ion during grain formation.

In the production of the organic silver salt dispersion of the present invention, it is important to prepare a uniform organic silver salt. However, the liquid becomes highly viscous during the preparation of the organic silver salt, and it is difficult to prepare a uniform organic silver salt. Therefore, a method capable of uniformly producing an organic silver salt even in a medium having a relatively high viscosity as described above is indispensable. In order to more effectively carry out the present invention, it is preferable to use a high-speed centrifugal radiation stirrer (dissolver mixer) that generates a stronger vortex and entrains components. This is to generate a vortex by rotating a toothed disk-shaped impeller, which is formed by alternately bending a circular saw blade up and down, at high speed. The vortex strongly entrains the generated powder and each component of the reaction, so that the reaction is performed more uniformly and the shearing force is strong, so that the effect of dispersing the formed powder is also exerted. More preferably, a high-speed rotary shear type stirrer is used, in which not only the unit stirring blade is rotated at high speed but also a combination of a stationary ring (stater) so as not to cause excessive cavitation near the outer periphery of the stirring blade. It is used. In this case, the strong shearing effect and impact generated between the rotor and the stationary ring can be used, and a strong axial flow is formed along the rotation axis of the stirring, so that the nucleation of organic silver salt particles is short. Since the reaction is efficiently performed along the axial flow at time, the reaction proceeds more uniformly. In addition, the axial flow also improves the uniformity in the direction of the rotation axis, and it is easier to ensure the uniformity even in a medium having a certain degree of fluid viscosity and the like. Also,
At least another auxiliary stirrer is preferably used in combination with the above-mentioned stirrer to ensure overall uniformity in the reaction vessel.

In the addition of the water-soluble silver salt of the present invention, an organic acid component such as an organic acid alkali metal or ammonium salt as an organic silver salt-forming component is uniformly reacted with a water-soluble silver salt such as silver nitrate. It is necessary to eliminate local non-uniformity in order to achieve this. For this purpose, it is necessary to prevent the two components (or one component in the case of a single jet) from being consumed quickly and to prevent local accumulation of unreacted components. This requires quick mixing of the reactants, and the added reactants need to be mixed immediately. For this reason, it is preferable that the reaction components are added in the liquid, also in the vicinity of the stirring and mixing machine, rather than in the liquid surface. The added components are now mixed and reacted immediately. Even in the case of ordinary stirring, a vortex is usually formed in the liquid and the liquid is stirred. However, it is necessary that the addition port of the reaction component is located at a position near the stirring member so as to be caught in the vortex. It means. This effect is particularly large when the viscosity of the reaction medium is high.

The shape of the reaction component addition port may be any as long as it does not hinder the above-mentioned effects, and may be a simple nozzle or a porous nozzle tip.

According to the present invention, for example, in the case of the double jet method, two addition ports for simultaneously adding two components near the stirring blade are provided, and one component of the reaction is placed in a reaction vessel. When the other component is mixed here, the mixing may be performed by providing one addition port for supplying the component to be added near the stirring blade.

Examples of the high-speed rotary shearing stirrer particularly preferably used in the present invention include the following. T. K. Combimix (manufactured by Tokushu Kika Kogyo Co., Ltd.), Satake Hybrid Mixer (manufactured by Satake Chemical Machinery Co., Ltd.), Vacuum emulsification stirrer (manufactured by Mizuho Industry Co., Ltd.), Vacuum emulsification and dispersion device Flimix (manufactured by Shinko Pantech Co., Ltd. )etc.

As one preferred embodiment of the present invention, FIG. 1 shows an example of an apparatus for preparing the organic silver salt of the present invention in which a plurality of stirrers are combined.

In FIG. 1, the reaction tank 1 provided with a jacket pot 6 for heating, cooling and maintaining the reaction temperature during the reaction has a non-uniformity due to the stagnation of the reaction solution particularly near the vessel wall. In order to prevent this, an anchor blade 2 which is normally used at a slower rotation than a stirring blade for the reaction is provided. The stirring blade for performing the reaction of the water-soluble silver salt is represented by a homomixer 5 which is a high-speed shearing stirring device. This is because the axial flow along the rotation axis of the homomixer 5 is formed from below to above the stirring blade in this case, so that the water-soluble silver addition nozzle 4 is provided immediately below the stirring blade in the immediate vicinity of the homomixer 5. Have been. An aqueous solution of silver nitrate is supplied from the immediate vicinity of the homomixer 5 to the organic acid alkali metal salt or the like and the other reaction component in the reaction tank through the nozzle 4, and is uniformly mixed and reacted through the high-speed shearing-type stirrer homomixer 5. In this case, the axial flow generated also increases the efficiency of stirring in the vertical direction, so that more uniform production becomes possible.

FIG. 1 is an enlarged view of the homomixer portion. The stirring blade 7 is rotated at a high speed by a rotating shaft 9 which rotates at a high speed, and a stationary ring 8 provided on the outer periphery of the stirring blade.
(State). Numeral 10 indicates the direction of the axial flow.

The manufacturing apparatus is additionally provided with a high-speed rotating centrifugal radiation type stirrer dissolver mixer 3, which is a large reaction vessel in which it is difficult to ensure uniformity in the reaction tank only with anchor blades. This is also to eliminate local bias of the concentration of the reaction component when using a tank. The use of a high speed centrifugal radial stirrer improves the uniformity of the reaction system through the formation of a vortex. In the above device, M represents a motor for each stirrer.

The peripheral speed of the anchor wing is 0.1
m / sec to 10 m / sec, more preferably 0.1 to 0.1 m / sec.
1 m / sec to 1.5 m / sec, particularly preferably 0.1
m / sec to 3 m / sec. Further, the peripheral speed of the stirring member of the above-mentioned disperser or homomixer is 1 m /
Sec to 100 m / sec is preferable, more preferably 1 m / sec to 30 m / sec, and particularly preferably 1 m / sec to 15 m.
/ Sec.

In the present invention, as described above, the organic silver salt is a reducible silver source, and a silver salt of an organic acid or a heteroorganic acid containing a reducible silver ion source, especially a long chain (10 to 3)
An aliphatic carboxylic acid having 0, preferably 15 to 25 carbon atoms) and a nitrogen-containing heterocyclic ring are preferred. When the ligand is 4.0
Organic or inorganic silver salt complexes having a total stability constant for silver ions of １10.0 are also useful. Examples of suitable silver salts are described in Research Disclosure (hereinafter R
D) 170170 and 29963, and include the following: silver salts of organic acids such as gallic acid, oxalic acid, behenic acid, arachidic acid, stearic acid, palmitic acid, lauric acid, etc. Silver salts); carboxyalkylthiourea salts of silver (eg, silver salts of 1- (3-carboxypropyl) thiourea, 1- (3-carboxypropyl) -3,3-dimethylthiourea); aldehydes and hydroxy-substituted aromatics Silver complexes (e.g., aldehydes (formaldehyde, acetaldehyde, butyraldehyde, etc.) and hydroxy-substituted acids (e.g., salicylic acid, benzoic acid,
Silver complex of a reaction product with 5-dihydroxybenzoic acid, 5,5-thiodisalicylic acid); silver salts or complexes of thiones (eg, 3- (2-carboxyethyl) -4-hydroxymethyl-4-thiazoline) -2-thione, and 3-
Silver salt or complex of carboxymethyl-4-thiazoline-2-thione); imidazole, pyrazole, urazole, 1,2,4-thiazole and 1H-tetrazole,
Complexes or salts of silver and nitrogen acids selected from 3-amino-5-benzylthio-1,2,4-triazole and benzotriazole; silver salts such as saccharin and 5-chlorosalicylaldoxime; and silver of mercaptides salt. Preferred silver sources are silver behenate, silver arachidate and / or silver stearate and silver palmitate.

Examples of the reducing agent used in the photothermographic material of the present invention include generally known reducing agents such as phenols, polyphenols having two or more phenol groups, naphthols and bisnaphthols. , 2
Polyhydroxybenzenes having at least two hydroxyl groups, 2
Polyhydroxynaphthalenes having at least two hydroxyl groups,
Ascorbic acids, 3-pyrazolidones, pyrazoline-
5-ones, pyrazolines, phenylenediamines, hydroxylamines, hydroquinone monoethers,
Hydroxamic acids, hydrazides, amide oximes, N-hydroxyureas, and the like. More specifically, for example, U.S. Patent Nos. 3,615,533 and 3,67.
9,426, 3,672,904, 3,7
No. 51,252, No. 3,782,949, No. 3,
Nos. 801,321, 3,794,488, 3,893,863, 3,887,376, 3,770,448, 3,819,382,
No. 3,773,512 and No. 3,839,048
No. 3,887,378, No. 4,009,03
9, No. 4,021,240, British Patent No. 1,48
No. 6,148 or Belgian Patent No. 786,086 and JP-A-50-36143, 50-36.
No. 110, No. 50-116023, No. 50-9971
No. 9, No. 50-140113, No. 51-51933
Nos. 51-23721, 52-84727 and JP-B-51-35851, and the present invention is appropriately selected from such known reducing agents. Can be used. As a selection method, the simplest method is to actually prepare a photothermographic material and evaluate the photographic performance of the photothermographic material to determine the superiority of the reducing agent used. Among the above reducing agents, when a silver aliphatic carboxylate is used as the organic silver salt, preferred reducing agents include polyphenols in which two or more phenol groups are linked by an alkylene group or sulfur, particularly a phenol group. An alkyl group (for example, a methyl group, an ethyl group, a propyl group, a t-butyl group, a cyclohexyl group, etc.)
Or polyphenols in which two or more phenol groups substituted by an acyl group (eg, acetyl group, propionyl group, etc.) are linked by an alkylene group or sulfur, for example, 1,1-bis (2-hydroxy-3,5-dimethylphenyl) ) -3,5,5-trimethylhexane, 1,1-
Bis (2-hydroxy-3-t-butyl-5-methylphenyl) methane, 1,1-bis (2-hydroxy-3,
5-di-t-butylphenyl) methane, 2-hydroxy-3-t-butyl-5-methylphenyl- (2-hydroxy-5-methylphenyl) methane, 6,6'-benzylidene-bis (2,4 -Di-t-butylphenol),
6,6'-benzylidene-bis (2-t-butyl-4-
Methylphenol), 6,6'-benzylidene-bis (2,4-dimethylphenol), 1,1-bis (2-
Hydroxy-3,5-dimethylphenyl) -2-methylpropane, 1,1,5,5-tetrakis (2-hydroxy-3,5-dimethylphenyl) -2,4-ethylpentane, 2,2-bis ( U.S. Pat. Nos. 3,589,903,4, such as 4-hydroxy-3,5-dimethylphenyl) propane and 2,2-bis (4-hydroxy-3,5-di-tert-butylphenyl) propane. , 021,249
Or British Patent Nos. 1,486,148 and JP-A-51-51933, 50-36110,
Polyphenol compounds described in JP-A-50-116023, JP-A-52-84727 or JP-B-51-35727, bisnaphthols described in U.S. Pat. No. 3,672,904, for example, 2,2 '-Dihydroxy-1,1'-binaphthyl, 6,6'-dibromo-2,2'-dihydroxy-1,1'-binaphthyl,
6,6'-dinitro-2,2'-dihydroxy-1,
1'-binaphthyl, bis (2-hydroxy-1-naphthyl) methane, 4,4'-dimethoxy-1,1'-dihydroxy-2,2'-binaphthyl and the like, and U.S. Pat.
Sulphonamidophenols or sulphonamidonaphthols as described in U.S. Pat.
Examples thereof include 2-benzenesulfonamidophenol, 2,6-dichloro-4-benzenesulfonamidophenol, and 4-benzenesulfonamidonaphthol.

The amount of the reducing agent used in the photothermographic material of the present invention varies depending on the type of the organic silver salt, the reducing agent, and other additives. 05 mol to 10 mol, preferably 0.1 mol to 3 mol
Molar is appropriate. Further, within this range, two or more of the above-mentioned reducing agents may be used in combination.

In the photothermographic material of the present invention, it is desirable to use an additive called a color tone agent, a color tone imparting agent or an activator toner (hereinafter referred to as a color tone agent) together with the above-mentioned components. The color tone agent participates in the oxidation-reduction reaction between the organic silver salt and the reducing agent, and has a function of making the resulting silver image dark, particularly black. Many kinds of compounds are already known as color toning agents, most of which are compounds having an imino group, a mercapto group or a thione group. An appropriate color tone agent may be selected from these depending on the type of the organic silver salt and the reducing agent used. Examples of the toning agent that provides a preferable toning effect in the photothermographic material of the present invention include phthalazinones (for example, phthalazinone, 2-acetylphthalazinone, 2-carbamoylphthalazinone, etc.) and 2-pyrazolin-5-ones (for example, 3-methyl-2-pyrazoline-
Quinazolines (eg, quinazoline, 4-
Methylquinazoline, etc.), pyrimidines (eg, 6-methyl-2,4-dihydroxypyrimidine, etc.), 1,2,5
-Triazines (eg, 3-methyl-4,6-dihydroxy-1,2,5-triazine etc.), phthalazinediones (eg, phthalazinedione, etc.), cyclic imides (eg, succinimides, phthalimides, urazoles) ,
Heterocyclic compounds having an imino group, such as benzoxazinediones and naphthalimides. Two or more of these color toning agents may be used in combination.
As described in JP-A-1020 and JP-A-53-55115, by using benzoxazinediones, benzothiazinediones or phthalimides in combination with phthalazinone, the color tone derived from storage under high temperature and high humidity. It is possible to prevent the effect from deteriorating.

As described in US Pat. Nos. 3,847,612 and 3,994,732, phthalic acid, naphthoic acid or phthalamic acid is used in combination with imidazoles or phthalazines. It can also be used as a toning agent.

When a toning agent is used, the amount of the toning agent is from 0.0001 mol to 2 mol, especially from 0.1 mol to 1 mol of the organic silver salt.
A range from 0005 mole to 1 mole is preferred.

The photothermographic material of the present invention may contain an antifoggant. Effective antifoggants include, for example, mercury compounds known from US Pat. No. 3,589,903. However, since these mercury compounds are environmentally unfavorable, non-mercury antifoggants have been studied for a long time. Preferred non-mercury antifoggants include, for example, those described in U.S. Pat. Nos. 4,546,075 and 4,452,885 and JP-A-59-57234.

Particularly preferred non-mercury antifoggants are described in US Pat. Nos. 3,874,946 and 4,756,9.
No. 99, -C (X ₁ )
(X ₂ ) (X ₃ ) (where X ₁ and X ₂ are halogen atoms and X
₃ is a heterocyclic compound having one or more substituents represented by a hydrogen atom or a halogen atom). Examples of these suitable antifoggants include compounds described in JP-A-9-288328, paragraphs [0030] to [0036].

As another preferred example of the antifoggant, JP-A-9-90550, paragraph [0062]
To [0063]. Further, other suitable antifoggants are disclosed in U.S. Pat.
8,523 and European Patent Nos. 600,587, 6
Nos. 05,981 and 631,176.

The photothermographic materials of the present invention include, for example, JP-A-63-159814, JP-A-60-140335 and JP-A-6-140335.
Nos. 3-231437, 63-259651 and 63
-304242, 63-15245, U.S. Pat. Nos. 4,639,414, 4,740,455, 4,741,966, 4,751,175, 4, Sensitizing dyes described in 835,096 can be used. Useful sensitizing dyes for use in the present invention are, for example, RD
17643 IV-A (p. 23, December 1978). In particular, a sensitizing dye having a spectral sensitivity suitable for the spectral characteristics of various scanner light sources can be advantageously selected. For example, Japanese Patent Application Laid-Open No. 60-162247 discloses an argon ion laser light source.
No. 2,486,635, U.S. Pat.
No. 331, West German Patent No. 936,071, JP-A-5-1
JP-A-50-6242 discloses simple merocyanines and helium neon laser light sources described in US Pat.
5, pp. 54-18726 and 59-102229, trinuclear cyanine dyes disclosed in JP-A-7-28733.
No. 48-42172 for merocyanines, LED light sources and infrared semiconductor laser light sources described in
No. 51-9609, No. 55-39818, JP-A-62-284343 and JP-A-2-105135, and JP-A-59-15959 for the infrared semiconductor laser light source. No.-191032, JP-A-60
Tricarbocyanines described in JP-A-80841, and dicarbocyanines containing a 4-quinoline nucleus described in formulas (IIIa) and (IIIb) of JP-A-59-192242 and JP-A-3-67242. And the like are advantageously selected. Further, when the wavelength of the infrared laser light source is 750 nm or more, more preferably 800 nm or more.
5-341432, 7-13295, Tokuhei 6
-52387, 3-10931, U.S. Pat.
Sensitizing dyes described in 441,866 and the like are preferably used.

These sensitizing dyes may be used alone.
In particular, combinations of sensitizing dyes are often used for supersensitization. Along with the sensitizing dye, the emulsion may contain a dye which does not itself have a spectral sensitizing effect or a substance which does not substantially absorb visible light and exhibits supersensitization. Exposure of the photothermographic material of the invention is performed using an argon ion laser (488 nm) and a He-Ne laser (633).
nm), a red semiconductor laser (670 nm), an infrared semiconductor laser (780 nm, 820 nm) and the like are preferably used. However, from the viewpoint that the laser power is high and the photosensitive material can be made transparent, the infrared semiconductor laser is used. Lasers are more preferably used.

In addition, a printout inhibitor and various additives for preventing discoloration due to printout of the unexposed area after the heat development treatment, such as a surfactant, an antioxidant, a stabilizer, a plasticizer, and an ultraviolet absorber Agents, coating aids and the like may be used in the photothermographic material of the present invention. These additives and the other additives described above are compounds described in RD17029 (pp. 9-15, June 1978). Can be preferably used. These additives may also be used in the photothermographic layer,
It may be added to any of the non-photosensitive layer and other layers.

As the binder used in the photothermographic material of the present invention, natural and synthetic polymers and copolymers can be used. For example, water-soluble polymers such as gelatin, polyvinyl alcohol and hydroxyethyl cellulose, cellulose acetate, cellulose acetate Butyrate, polyvinylpyrrolidone, polymethyl methacrylate, polyvinyl chloride, copoly (styrene-maleic anhydride), copoly (styrene-acrylonitrile), copoly (styrene-butadiene), polyvinylacetals, for example, polyvinylformal, polyvinylbutyral, polyvinyl There are water-insoluble polymers such as acetates and cellulose esters. However, among these binders, particularly preferred are water-insoluble polymers such as cellulose acetate, cellulose acetate butyrate and polyvinyl butyral, and among them, polyvinyl butyral is particularly preferred.

In the present invention, the binder amount of the photosensitive layer is preferably 1.5 to 6 g / m ² . More preferably, it is 1.7 to 5 g / m ² . If it is less than 1.5 g / m ² , the density of the unexposed portion will increase significantly and may not be usable.

Each component used in the photothermographic material of the present invention is dispersed in at least one kind of colloid as a binder. Suitable binders include the above-mentioned hydrophobic polymer materials, and as described above, polyvinyl butyral is the most preferable as the binder used for the photosensitive layer. Also, if necessary, these polymer materials
More than one species may be used in combination. The amount of the polymer material used is an amount sufficient to support the components dispersed or dissolved therein, that is, an amount effective as a binder. The range can be appropriately determined by those skilled in the art. For example, in the case where at least an organic silver salt is dispersed and supported, the mass ratio to the organic silver salt is 10: 1 to 1: 1.
0, especially in the range of 4: 1 to 1: 4.

The composition containing each component of the photothermographic material of the present invention is usually divided into one layer or two or more layers on various supports selected from a wide range of materials while being supported on the binder. It is applied. Examples of the material of the support include various polymer materials, glass, wool cloth, cotton cloth, paper, metal (for example, aluminum) and the like. When handling as an information recording material, it is processed into a flexible sheet or roll. What can be done is preferred. Therefore, as a support in the photothermographic material of the present invention, a plastic film (for example, a cellulose acetate film, a polyester film, a polyethylene terephthalate film,
A polyethylene naphthalate film, a polyamide film, a polyimide film, a cellulose triacetate film, a polycarbonate film, or the like) is preferable, and in the present invention, a biaxially stretched polyethylene terephthalate film is particularly preferable in the present invention as described above.

The method of applying each layer of the light-sensitive material of the present invention is not particularly limited, and a known method such as a bar coater method, a curtain coat method, an immersion method, an air knife method, and a hopper application method can be used. More preferably, a pre-metering type coating method called an extrusion method is preferable.

The light-sensitive material of the present invention is preferably provided with a protective layer and a back coat layer in addition to the photothermographic layer.
If necessary, the photothermographic layer may have a two-layer structure having different sensitivities, or an intermediate layer may be provided between them.

The binder for the protective layer is preferably a water-insoluble polymer such as cellulose acetate, cellulose acetate butyrate and polyvinyl butyral, and particularly preferably cellulose acetate or cellulose acetate butyrate.

The preferred thickness of the photothermographic layer containing silver halide of the present invention is 0.2 to 40 μm per layer.
More preferably, it is 2 to 30 μm.

The thickness of the surface protective layer is preferably from 0.2 to 10 μm, more preferably from 1 to 5 μm per layer.

The preferred thickness of the back coat layer is 0.2 to 10 μm, more preferably 1 to 5 μm per layer.

In the present invention, it is advantageous that a small amount of material is included during thermal development of the photothermographic material. As these solvents, those used as coating solvents for the photothermographic layer and the protective layer may be left in a small amount, or may be contained in a small amount by applying a separate solvent or spraying. This improves the heat development characteristics and can achieve higher gamma and lower fog, which is preferable.

Examples of these solvents include ketones such as acetone, isophorone, ethyl amyl ketone,
Examples include methyl ethyl ketone and methyl isobutyl ketone. Alcohols include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, diacetone alcohol, cyclohexanol, benzyl alcohol and the like. Glycols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, hexylene glycol and the like. Examples of ether alcohols include ethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and the like. Examples of ethers include ethyl ether, dioxane, and isopropyl ether. Examples of the esters include ethyl acetate, butyl acetate, amyl acetate, and isopropyl acetate. N-pentane, n-hexane, n
-Heptane, cyclohexane, benzene, toluene, xylene and the like. Examples of chlorides include methyl chloride, methylene chloride, chloroform, dichlorobenzene and the like. Examples of the amines include monomethylamine, dimethylamine, triethanolamine, ethylenediamine, and triethylamine. Other examples include water, formamide, dimethylformamide, nitromethane, pyridine, toluidine, tetrahydrofuran, acetic acid and the like. However, it is not limited to these. These solvents can be used alone or in combination of several kinds.

The content of the solvent in the photosensitive material can be adjusted by changing conditions such as temperature conditions in a drying step after the coating step. The content of the solvent can be measured by gas chromatography under conditions suitable for detecting the contained solvent.

The amount of the solvent contained in the light-sensitive material according to the present invention is the total amount (based on mass) per 1 m ² of the light-sensitive material.
Needs to be adjusted to be 5 to 1000 mg / m ² .

When the content is within the above range, a photothermographic material having a low fog density while having high sensitivity can be obtained.

In the present invention, in order to write image data on the photothermographic material, the exposure is preferably performed by laser scanning exposure. However, the angle between the exposed surface of the photosensitive material and the scanning laser beam is substantially perpendicular. It is preferable to use a laser scanning exposure machine which does not cause such a problem.

Here, "not substantially vertical" means that the angle is closest to vertical during laser scanning, preferably 55 to 88 degrees, more preferably 60 to 86 degrees, and still more preferably. 65 degrees or more and 84 degrees or less, most preferably 70 degrees or more and 82 degrees or less.

The beam spot diameter on the exposed surface of the photosensitive material when the laser light is scanned on the photosensitive material is preferably 200 μm or less, more preferably 100 μm or less. It is preferable that the spot diameter is small in that the shift angle of the laser incident angle from the perpendicular can be reduced. Incidentally, the adjustment of the beam spot diameter is 10 μm. By performing such laser scanning exposure, it is possible to reduce image quality degradation related to reflected light such as occurrence of interference fringe-like unevenness.

It is also preferable that the exposure in the present invention is performed by using a laser scanning exposure machine that emits a scanning laser beam which is a vertical multi. Image quality deterioration such as generation of interference fringe-like unevenness is reduced as compared with the scanning laser beam in the longitudinal single mode.

[0086] In order to form the vertical multiple, it is preferable to use a method of combining, using return light, or superimposing a high frequency. still,
The vertical multi means that the exposure wavelength is not single, and the distribution of the exposure wavelength is usually 5 nm or more, preferably 10 nm or more. The upper limit of the exposure wavelength distribution is not particularly limited, but is usually about 60 nm.

By these writing means, an image having less unevenness and excellent sharpness can be obtained.

The development conditions of the photothermographic material of the present invention vary depending on the composition, constitution, structure, etc. of the material used. This is done by heating. The latent image formed by exposure is heated at a moderately high temperature (for example, about 80 ° C. to 250 ° C., preferably about 100 ° C. to 200 ° C.) for a sufficient time (generally about 1 second to about 2 minutes). And becomes a silver image and is visualized (developed). The heating may be performed by a typical heating means such as a hot plate, an iron, a heat roller, a heat generator using carbon or white titanium or the like. Among these, the method of carrying and heating and developing while contacting with a heat roller is preferable from the viewpoint of thermal efficiency and workability.

The heating of the photothermographic material is preferably carried out from the protective layer side in terms of heat transfer efficiency, and disadvantages such as uneven heating due to heating from the support side and time required for heat transfer can be avoided. .

As a result, a high-quality silver image can be obtained only by complete heating.

[0091]

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

<< Preparation of Photographic Support >> Density 0.170
(Measured with a densitometer PDA-65 manufactured by Konica Corporation) A corona discharge treatment of 8 W / m ² · min was applied to both sides of a 175 μm thick PET film colored blue.

<< Preparation of Photosensitive Silver Halide Emulsion A >> (Solution A1) Phenylcarbamoylated gelatin 88.3 g Compound (A) (10% aqueous methanol solution) 10 ml Potassium bromide 0.32 g Finish with water to 5429 ml (solution B1) ) 0.635 mol / L aqueous solution of silver nitrate 2635 ml (solution C1) 51.55 g of potassium bromide 1.47 g of potassium iodide Make up to 660 ml with water (solution D1) 154.9 g of potassium bromide 4.41 g of iridium chloride (solution I) (1% solution) 0.93 ml Finish to 1982 ml with water (Solution E1) 0.4 mol / L aqueous potassium bromide solution Silver potential control amount below (Solution F1) 0.71 g of potassium hydroxide Finish to 20 ml with water (Solution G1) 56% aqueous acetic acid solution 18.0 ml (solution H1) anhydrous sodium carbonate 1. Compounds finish 151ml with 2g water _{(A): HO (CH 2} CH 2 O) n - (CH (C
H ₃ ) CH ₂ O) ₁₇ − (CH ₂ CH ₂ O) _m H where m +
n = 5-7.

JP-B-58-58288, 58-58
Using a mixing stirrer described in No. 289, 1/4 of the solution B1 and the entire amount of the solution C1 were added to the solution A1 at a temperature of 45 ° C. and pAg.
While controlling at 8.09, the mixture was added by the simultaneous mixing method in 4 minutes and 45 seconds to form nuclei. One minute later, the entire amount of solution F1 was added. After a lapse of 6 minutes, the Ｂ amount of the solution B1 and the entire amount of the solution D1 were added over 14 minutes and 15 seconds by a simultaneous mixing method while controlling the temperature at 45 ° C. and the pAg at 8.09. After stirring for 5 minutes, the temperature was lowered to 40 ° C., and the whole amount of the solution G1 was added to precipitate a silver halide emulsion. The supernatant was removed except for 2000 ml of the sedimented portion, 10 liters of water was added, and after stirring, the silver halide emulsion was sedimented again. The supernatant was removed, leaving 1500 ml of the sedimented portion, and 10 liters of water was further added. After stirring, the silver halide emulsion was sedimented. After removing the supernatant liquid leaving 1500 ml of the sedimented portion, the solution H1 was added, the temperature was raised to 60 ° C., and the mixture was further stirred for 120 minutes. Finally, the pH was adjusted to 5.8, and water was added so as to be 1161 g per mol of silver, whereby photosensitive silver halide emulsion A was obtained. This emulsion was monodispersed cubic silver iodobromide grains having an average grain size of 0.058 μm, a grain size variation coefficient of 12%, and a [100] face ratio of 92%.

<< Preparation of Powdered Organic Silver Salt A >> Behenic acid 130.8 g and arachidic acid 67.7 in 4720 ml of pure water.
g, 43.6 g of stearic acid and 2.3 g of palmitic acid were dissolved at 80 ° C. At that time, a general propeller type stirring blade was used. Next, a 1.5 M aqueous sodium hydroxide solution 5
40.2 ml was added. Next, 6.9 ml of concentrated nitric acid was added, and the mixture was cooled to 55 ° C. to obtain a sodium organic acid solution.

The temperature of the above-mentioned organic acid sodium acid solution was 55
While maintaining the temperature at 4 ° C., 45.3 g of photosensitive silver halide emulsion A and 450 ml of pure water were mixed and added, followed by stirring for 5 minutes.
Next, 760.6 ml of a 1M silver nitrate solution was added to the solution over 2 minutes. The mixture was further stirred for 10 minutes to obtain an organic silver salt dispersion.

Thereafter, the obtained organic silver salt dispersion was transferred to a washing vessel, deionized water was added thereto, and the mixture was stirred and allowed to stand. Then, the organic silver salt dispersion was floated and separated, and the lower water-soluble salts were removed. . Thereafter, washing with deionized water and draining are repeated until the conductivity of the waste water becomes 50 μS / cm, and after centrifugal dehydration, drying is performed at 40 ° C. using a hot-air circulating dryer until there is no change in mass. A powdered organic silver salt A was obtained. << Preparation of Powdered Organic Silver Salt B >> An organic silver salt was prepared as follows using an apparatus shown in FIG. 1 modified based on Combimix SL-10 manufactured by Tokushu Kika Kogyo Co., Ltd.

The rotation speed of the anchor blade 2 is 100 rpm, and the rotation speeds of the dissolver mixer 3 and the homomixer 5 are 15
130.8 g of behenic acid, 67.7 g of arachidic acid, 43.6 g of stearic acid and 2.3 g of palmitic acid were dissolved in 4720 ml of pure water at 80 ° C. in a reaction vessel at 00 rpm. At this time, the rotational directions of the dissolver mixer 3 and the homomixer 5 were set to be opposite to each other. Next, 540.2 ml of a 1.5 M aqueous sodium hydroxide solution was added. Next, 6.9 ml of concentrated nitric acid was added. Then 55
It cooled to ° C and obtained the organic acid sodium solution. At this time, the temperature of the organic acid sodium solution is kept at 55 ° C.

Using a processing apparatus shown in FIG. 2 for ultrafiltrating a photosensitive silver halide emulsion, a mixture of 45.3 g of photosensitive silver halide emulsion A and 450 ml of pure water was separated by an ultrafiltration unit 13. did. As a separation membrane used in the ultrafiltration unit 13, a mini cloth module manufactured by Microgon Co., Ltd .: M24S03001N (molecular weight cut off: 40)
0000) was used. The liquid sending pump 14 is provided with an RP pump of Daido Metal Industry Co., Ltd.

Next, the number of rotations of the anchor blade 2 in the reaction tank was set to 1
The rotation speed of each of the dissolver mixer 3 and the homomixer 5 was set to 2500 rpm, and the silver halide emulsion separated above was added to the reaction vessel and stirred for 5 minutes. Next, the rotation speed of the anchor blade 2 was set to 120 rpm, and the rotation speeds of the dissolver mixer 3 and the homomixer 5 were set to 5000 rpm.
Then, 760.6 ml of a 1M silver nitrate solution was added to the solution over 2 minutes. Furthermore, the rotation speed of the dissolver mixer 3 and the homomixer 5 were each set to 4500 rpm, and the mixture was stirred for 10 minutes to obtain an organic silver salt dispersion.

Thereafter, the obtained organic silver salt dispersion was transferred to a washing vessel, deionized water was added thereto, and the mixture was stirred and allowed to stand. Then, the organic silver salt dispersion was floated and separated, and the lower water-soluble salts were removed. . Thereafter, washing with deionized water and draining are repeated until the conductivity of the waste water becomes 50 μS / cm, and after centrifugal dehydration, drying is performed at 40 ° C. using a hot-air circulating dryer until there is no change in mass. Powder organic silver salt B was obtained.

<< Preparation of photosensitive emulsion dispersions 1 and 2 >> Polyvinyl butyral powder (Butv, manufactured by Monsanto Co., Ltd.)
ar B-79) was dissolved in 1457 g of methyl ethyl ketone (hereinafter abbreviated as MEK) to give VMA-G
Dissolver DISPERMAT C manufactured by ETZMANN
500g of powdered organic silver salt A while stirring with A-40M type
Was gradually added and mixed well to prepare a preliminary dispersion. Next, 1mm diameter Zr beads (Toray)
Disperser (gettzman) filled with 80% of
The dispersion was carried out at a peripheral speed of 13 m and a residence time of 3 minutes in a mill to prepare a photosensitive emulsion dispersion liquid 1.

Photosensitive emulsion dispersion liquid 2 was obtained in exactly the same manner as in preparation of photosensitive emulsion dispersion liquid 1, except that powdered organic silver salt B was used instead of organic silver salt A.

<< Preparation of Stabilizer Liquid >> 1.0 g of stabilizer 1,
0.31 g of potassium acetate was dissolved in 4.97 g of methanol to prepare a stabilizer solution.

<< Preparation of Infrared Sensitizing Dye Liquid >> 19.2 mg of infrared sensitizing dye 1, 1.488 g of 2-chloro-benzoic acid, 2.779 g of stabilizer 2, and 365 mg of 5-methyl-2 31.3 m of mercaptobenzimidazole
The solution was dissolved in 1 K of MEK in the dark to prepare an infrared sensitizing dye solution.

<< Preparation of Additive Solution a >> 27.98 g of 1,1
-(2-hydroxy-3,5-dimethylphenyl) -2
-Methylpropane, 1.54 g of 4-methylphthalic acid,
0.48 g of Infrared Dye 1 was dissolved in 110 g of MEK to prepare Additive Solution a.

<< Preparation of Additive Liquid b >> 2.56 g of the antifoggant 2, 3.43 g of phthalazine were dissolved in 40.9 g of MEK (methyl ethyl ketone) to obtain an additive liquid b.

<< Preparation of Photosensitive Layer Coating Solution >> The above-mentioned photosensitive emulsion dispersion liquid 1 (50 g) and MEK 15.11 g were kept at 21 ° C. while stirring, and 390 μl of antifoggant 1 (10% methanol solution) was added. Stirred for hours. Further, 494 μl of calcium bromide (10% methanol solution) was added, and the mixture was stirred for 20 minutes. Subsequently, 167 mg of a stabilizer solution was added and stirred for 10 minutes, and then 2.622 g of an infrared sensitizing dye solution was added and stirred for 1 hour. Thereafter, the temperature is increased to 13
The temperature was lowered to ° C, and the mixture was further stirred for 30 minutes. While keeping the temperature at 13 ° C., polyvinyl butyral (Monsanto)
(Butvar B-79)
After stirring for minutes, tetrachlorophthalic acid (9.4% by mass M
EK solution) and stirred for 15 minutes.
While further stirring, 12.43 g of the additive liquid a,
3. 1.6 ml of Desmodur N3300 / Mobay's aliphatic isocyanate (10% MEK solution);
27 g of the additive solution b was sequentially added and stirred to obtain a photosensitive layer coating solution 1. Photosensitive emulsion 2 was prepared in the same manner to obtain photosensitive layer coating solution 2.

<< Preparation of Matting Agent Dispersion >> Cellulose acetate butyrate (Eastman Chemical)
Co., Ltd., 7.5 g of CAB171-15)
g of calcium carbonate (Specia)
liter Minerals, Super-Pfle
x200), and dispersed with a dissolver-type homogenizer at 8000 rpm for 30 minutes to prepare a matting agent dispersion.

<< Preparation of Surface Protective Layer Coating Solution >> While 865 g of MEK (methyl ethyl ketone) was stirred, cellulose acetate butyrate (Eastman Chemical) was used.
al, CAB171-15): 96 g, polymethyl methacrylic acid (Rohm & Haas, Paraloid A-2)
1): 4.5 g, vinyl sulfone compound (HD-1):
1.5 g, benzotriazole: 1.0 g, and F-based activator (Asahi Glass Co., Ltd., Surflon KH40): 1.0 g were added and dissolved. Next, 30 g of a matting agent dispersion was added and stirred to prepare a coating solution for the surface protective layer.

[0111]

Embedded image

[0112]

Embedded image

<< Coating of Photosensitive Layer Surface Side >> The photosensitive layer coating liquid and the surface protective layer coating liquid were simultaneously layer-coated by using an extrusion coater to prepare photosensitive materials 1 and 2 as shown in Table 1. The coating was performed such that the photosensitive layer had a coated silver amount of 1.9 g / m ² and the surface protective layer had a dry film thickness of 2.5 μm. Thereafter, drying was performed for 10 minutes using a drying air having a drying temperature of 75 ° C. and a dew point temperature of 10 ° C.

<< Back side coating >> (Preparation of back side coating liquid) 830 g of methyl ethyl ketone
While stirring the cellulose acetate butyrate (E
astman Chemical, CAB 381-2
0) 84.2 g, polyester resin (Bostic,
(VitelPE2200B) 4.5 g was added and dissolved. To the dissolved solution, 0.30 g of infrared dye 1 was added,
Further, 4.5 g of an F-based activator (Surflon KH40, Asahi Glass Co., Ltd.) and 2.3 g of an F-based activator (Dainippon Inc., Megafag F120K) dissolved in 43.2 g of methanol.
Was added and the mixture was sufficiently stirred until it was dissolved. Finally, silica (WR Gra) dispersed in methyl ethyl ketone at a concentration of 1% by mass with a dissolver-type homogenizer.
75 g of Syloid 64X6000 (ce Co.) was added and stirred to prepare a coating solution for the back surface.

(Coating of Back Surface) The back surface coating solution prepared as described above was extruded using a coater so that the dry film thickness became 3.5 μm. And dried. The drying was performed over 5 minutes using a drying air having a drying temperature of 100 ° C. and a dew point temperature of 10 ° C.

<< Measurement of Solvent Content in Film >> A film area of 46.3 cm ² was cut out and cut into 5 mm.
It was finely chopped, stored in a dedicated vial, sealed with a septum and an aluminum cap, and set in a Hewlett-Packard HP7694 headspace sampler. For gas chromatography (GC) connected to a headspace sampler, a Hewlett-Packard type 5971 equipped with a flame ionization detector (FID) was used as a detector. The main measurement conditions are as follows.

Headspace sampler heating conditions: 12
0 ° C, 20 minutes GC introduction temperature: 150 ° C Column: DB-624 manufactured by J & W Increasing temperature: 45 ° C, holding for 3 minutes → 100 ° C (8 ° C / min) A gas chromatogram was obtained using the above measurement conditions. The solvent to be measured was MEK and methanol, and a predetermined amount diluted with each of butanol in the solvent on the left was stored in a dedicated vial, and then prepared using the peak area of the chromatogram obtained by measuring in the same manner as above. The solvent content in the film was obtained using a calibration curve.

<< Exposure and development processing >> From the emulsion side of the photosensitive material prepared as described above, 800 nm
Exposure was performed by laser scanning using an exposing machine using a semiconductor laser having a vertical multi-mode of about 820 nm as an exposure source. At this time, an image was formed at an angle of 75 degrees between the exposure surface of the photosensitive material and the exposure laser beam. (Note that the angle is 9
An image with less unevenness and unexpectedly good sharpness and the like was obtained compared to the case where the angle was set to 0 degree. Thereafter, using an automatic developing machine having a heat drum, the protective layer of the photosensitive material and the drum surface are brought into contact with each other to obtain 11
The film was thermally developed at 0 ° C. for 15 seconds. At that time, exposure and development were performed in a room conditioned at 23 ° C. and 50% RH. The obtained image was evaluated using a densitometer. The result of the measurement was evaluated by sensitivity (the reciprocal of the ratio of the exposure amount giving a density higher than that of the unexposed portion by 1.0).

<< Evaluation of Raw Preservability >> 3.5 cm × 16 cm
The heat-developable photosensitive material sample was cut into two sheets each, one sheet was kept at 25 ° C. and 55% RH for 3 days, and the other sheet was cut at 5%.
After storing at 5 ° C. and 55% RH for 3 days, development processing was performed in the same manner as in the evaluation of sensitivity without exposure. ΔDmin obtained by the following formula is shown as raw preservability.

Raw preservability (ΔDmin) = Dmin (55
° C, 55% RH for 3 days)-Dmin (25 ° C, 5%
(Stored at 5% RH for 3 days) The obtained results are shown in Table 1.

[0121]

[Table 1]

From Table 1, it can be seen that the sample of the present invention has high sensitivity,
It is clear that both the raw preservability is good.

[0123]

According to the present invention, a method for uniformly producing an organic silver salt dispersion used for a photothermographic material, a photothermographic material having high sensitivity and good raw storability, an image recording method and an image using the same. A forming method can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic view showing one example of an apparatus for producing an organic silver salt dispersion of the present invention.

FIG. 2 is a schematic view showing one example of a processing apparatus for ultrafiltrating a photosensitive silver halide emulsion according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reaction tank 2 Anchor blade 3 Dissolver mixer 4 Addition nozzle 5 Homo mixer 6 Jacket pot 7 Stirrer blade 8 Fixed ring 9 Rotating shaft 10 Axial flow direction M Motor 11 Stirrer tank 12 Stirrer blade 13 Ultrafiltration unit 14 Ultrapump pump 15 Diaphragm valve 16 Pressure gauge (outside) 17 Pressure gauge (entrance) 18 Flow meter

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) G03C 5/08 351 G03C 5/08 351

Claims (7)

[Claims] 1. An aqueous solution or suspension of an alkali salt of an organic acid is added with an aqueous solution of nitric acid, then photosensitive silver halide grains are added, and a water-soluble silver salt is further added to react in a reaction vessel.
A method for producing an organic silver salt dispersion, wherein the emulsion containing the photosensitive silver halide particles is subjected to ultrafiltration treatment and then added to the reaction vessel. 2. The method for producing an organic silver salt dispersion according to claim 1, wherein the photosensitive silver halide particles are monodispersed. 3. The method according to claim 1, wherein the organic silver salt dispersion is formed by a device in which the stirring A along the inner wall or the bottom in the reaction layer and the stirring B by the high-speed stirring member rotating at high speed are simultaneously performed. 3. The method for producing an organic silver salt dispersion according to 1 or 2. 4. A photothermographic material having a photosensitive layer containing a photosensitive silver halide, an organic silver salt, a reducing agent and a binder on a support and a protective layer, wherein a dispersion of the organic silver salt is used. Item 4. A photothermographic material produced by the production method according to any one of items 1 to 3. 5. An image recording method according to claim 4, wherein the exposure is performed by an exposure device in which the angle between the exposed surface of the photothermographic material and the scanning laser beam does not become substantially perpendicular. 6. An image forming method, wherein the photothermographic material according to claim 4 is heat-developed in a state where the photothermographic material contains 5 to 1000 mg / m ^{2 of a} solvent. 7. An image forming method, comprising: bringing a protective layer of the photothermographic material according to claim 4 into contact with a heated drum to perform development.