JP4032546B2 - Organic silver salt dispersion manufacturing method, manufacturing apparatus, photothermographic material, and image forming method using the same - Google Patents

Description

【０１１７】
【化２】

【０１１８】

〈感光層面側塗布〉
感光層：前記の組成の液をそれぞれ塗布銀量２ｇ／ｍ²になる様に塗布した。
【０１１９】
表面保護層：以下の組成の液を感光層の上に塗布した。
【０１２０】

《フィルム中溶剤含有量の測定》
フィルム面積として４６．３ｃｍ²を切り出し、これを５ｍｍ程度に細かく刻んで専用バイアル瓶に収納しセプタムとアルミキャップで密閉した後、ヒューレット・パッカード社製ヘッドスペースサンプラーＨＰ７６９４にセットした。ヘッドスペースサンプラーと接続したガスクロマトグラフィー（ＧＣ）は検出器として水素炎イオン化検出器（ＦＩＤ）を装着したヒューレットパッカード社製５９７１型であった。主な測定条件として、ヘッドスペースサンプラー加熱条件：１２０℃、２０分であり、ＧＣ導入温度：１５０℃、カラム：Ｊ＆Ｗ社製ＤＢ−６２４、昇温：４５℃、３分から１００℃（８℃／分）を用いてガスクロマトグラムを得た。測定対象溶媒は、ＭＥＫ、メタノールとし、左記溶剤の各々のブタノールにて希釈された一定量を専用バイアル瓶に収納した後、上記と同様に測定して得られたクロマトグラムのピーク面積を用いて作成した検量線を使用してフィルム中溶剤含有量を得た。
【０１２１】
《露光及び現像処理》
上記のように作製した感光材料の乳剤面側から、高周波重畳にて波長８００ｎｍ〜８２０ｎｍの縦マルチモード化された半導体レーザーを露光源とした露光機によりレーザー走査による露光を与えた。この際に、感光材料の露光面と露光レーザー光の角度を７５度として画像を形成した。（なお、当該角度を９０度とした場合に比べムラが少なく、かつ予想外に鮮鋭性等が良好な画像が得られた。）その後 ヒートドラムを有する自動現像機を用いて感光材料の保護層とドラム表面が接触するようにして、１１０℃で１５秒熱現像処理した。その際、露光及び現像は２３℃、５０％ＲＨに調湿した部屋で行った。得られた画像の評価を濃度計により行った。測定の結果は、感度（未露光部分よりも１．０高い濃度を与える露光量の比の逆数）およびカブリで評価し、感度は感光材料１の感度を１００とし相対値で、カブリは実測値で示した。結果を表１に示した。
【０１２２】
【表１】

【０１２３】
実施例２
実施例１と同じ装置を用いて以下のように有機銀塩を調製した。
【０１２４】
有機銀塩Ｃ：有機銀塩Ａの処方と同じで硝酸銀添加ノズルは液表面に設置し、撹拌はアンカー翼のみで行い、使用する１Ｍ硝酸銀の量を８１１ｍｌとした。硝酸銀量は有機酸に対し３モル％過剰。
【０１２５】
有機銀塩Ｄ：有機銀塩Ａの処方と同じで硝酸銀添加ノズルは液表面に設置し、同じく撹拌はアンカー翼のみで行い、使用する１Ｍ硝酸銀の量を７１７ｍｌとした。硝酸銀量は有機酸に対し９１モル％量。
【０１２６】
有機銀塩Ｅ：有機銀塩Ｂの処方と同じで硝酸銀添加ノズルはホモミクサ近傍に設置し、ただし、使用する１Ｍ硝酸銀の量を７４７ｍｌとした。有機酸に対し９５モル％量。
【０１２７】
有機銀塩Ｆ：有機銀塩Ｅの処方と同じ。ただし、使用する１Ｍ硝酸銀の量を７１７ｍｌとした。有機酸に対し９１モル％量。
【０１２８】
上記の有機銀塩Ｂ〜Ｅを用いて実施例１と全く同様の方法により感光材料３〜６を作製し同様にして露光、熱現像を行いカブリ最大濃度を評価した結果を表２に示した。但し最大濃度は感光材料３の最大濃度を１００としたときの相対値で示した。
【０１２９】
【表２】

【０１３０】
本発明の方法にて調製された有機銀塩を用いた感光材料はカブリが低く抑えられ最大濃度も高いことが判る。
【０１３１】
【発明の効果】
熱現像感光材料に用いる有機銀塩分散物を均一に形成でき、性能の安定した高い感度、カブリの低いた熱現感光材料および画像形成方法を得ることが出来た。
【図面の簡単な説明】
【図１】本発明の有機銀塩分散物の製造装置の一例を示す概略図である。
【符号の説明】
１ 反応槽
２ アンカー翼
３ ディゾルバミクサ
４ 添加ノズル
５ ホモミクサ
６ ジャケット釜
７ 撹拌翼
８ 固定環
９ 回転軸
１０ 軸流の方向
Ｍ モータ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for producing an organic silver salt dispersion and an image forming method for producing a photothermographic material or photothermographic material for a laser imager or laser imagesetter.
[0002]
[Prior art]
As a method for preparing an organic silver salt as a silver supplier used for the heat developing material, various methods are known. For example, a method for preparing an organic silver salt in a coexisting solution of water and a poorly water-soluble solvent, such as JP-A-49-93310, JP-A-49-94619, and JP-A-53-68702, A method for preparing an organic silver salt in an organic solvent, as described in JP-A-57-186745, JP-A-47-9432 and US Pat. No. 3,700,458, JP-A-53-31611, And a method of preparing an organic silver salt in an aqueous solution, such as JP 54-4117, JP 54-46709, and US Pat. No. 5,434,043.
[0003]
On the other hand, in order to impart photosensitivity to the heat-developable material, a method of incorporating silver halide into the heat-developable material is widely known, but this silver halide is based on a conventional aqueous silver halide gelatin emulsion method. It is very advantageous from the viewpoint of ease of introduction of techniques such as size control, crystal wall control, impurity doping, chemical ripening and the like.
[0004]
However, when preparing an organic silver salt in the presence of an organic solvent, or when preparing an organic silver salt in an organic solvent, the silver halide rendered hydrophilic by such gelatin must be uniformly dispersed in the organic silver salt. Is difficult, and it is very difficult to obtain desired Dmax and sensitivity in terms of photographic characteristics.
[0005]
Therefore, generally, a method of adding silver halide at the stage of preparing an organic silver salt in an aqueous solution is employed. In this sense, the organic silver salt is advantageously prepared in an aqueous solution. An organic silver salt dispersion in an aqueous solution is prepared by dissolving an organic fatty acid in water at a temperature equal to or higher than its melting point, then reacting with alkali hydroxide, adding an emulsion when the temperature is lowered, and further adding a water-soluble silver salt. A method is known in which an organic silver salt dispersion is formed by adding. However, when the temperature is lowered after the alkali hydroxide addition, the viscosity of the dispersion rapidly increases, and when the water-soluble silver salt is added, the viscosity further increases, so the uniformity of the dispersion at that time is not maintained, The formed organic silver particles became non-uniform and caused an increase in fog.
[0006]
[Problems to be solved by the invention]
An object of the present invention is to provide a method and an apparatus for uniformly forming an organic silver salt dispersion used in a photothermographic material, and further, a photothermographic material having improved sensitivity and fog and image formation. It is to provide a method.
[0007]
[Means for Solving the Problems]
  The object of the present invention is as follows.3-9It is achieved by means ofReference numerals 1 and 2 are reference means.
[0008]
1. A method for producing an organic silver salt dispersion by reacting an aqueous alkali salt solution or suspension of an organic acid with a water-soluble silver salt in a reaction vessel, the reaction vessel comprising at least one stirring member, A method for producing an organic silver salt dispersion, comprising adding a water-soluble silver salt through a nozzle installed in the vicinity.
[0009]
2. A production apparatus having a reaction vessel for reacting an aqueous solution or suspension of an organic acid alkali salt with a water-soluble silver salt to form an organic silver salt dispersion, comprising at least one stirring member in the production apparatus, An apparatus for producing an organic silver salt dispersion, comprising a nozzle for adding a water-soluble silver salt in the vicinity thereof.
[0010]
3.Long chain (10-30 carbon atoms) aliphatic carvoneA method for producing an organic silver salt dispersion in a reaction tank by adding a water-soluble silver salt to an aqueous alkali salt solution or suspension of an acid, in the reaction tank, stirring along the inner wall or bottom, Stirring by at least one high-speed stirring member that rotates at a high speed is performed simultaneously, and a water-soluble silver salt is added via a nozzle installed in the vicinity of the high-speed stirring member. .
[0011]
4).Long chain (10-30 carbon atoms) aliphatic carvoneA manufacturing apparatus having a reaction tank for forming an organic silver salt dispersion by adding a water-soluble silver salt to an aqueous alkali salt solution or suspension of an acid, and stirring in the reaction tank along the inner wall or bottom An apparatus for producing an organic silver salt dispersion, comprising: a member that performs the above operation; at least one high-speed stirring member that rotates at a high speed; and a nozzle that adds a water-soluble silver salt in the vicinity of the high-speed stirring member.
[0012]
5.Long chain (10-30 carbon atoms) aliphatic carvoneA method for producing an organic silver salt dispersion in a reaction tank by adding a water-soluble silver salt to an aqueous alkali salt solution or suspension of an acid, in the reaction tank, stirring along the inner wall or bottom, Agitation by at least one high-speed agitating member rotating at high speed is simultaneously performed, and silver nitrate corresponding to 0.9 to 0.97 mol per mol of organic acid is added through a nozzle installed in the vicinity of the high-speed agitating member. A method for producing an organic silver salt dispersion characterized by the above.
[0013]
6). A photothermographic material having a photosensitive layer containing a photosensitive silver halide, an organic silver salt, a reducing agent and a binder and a protective layer on a support, wherein the organic silver salt dispersionNote 3Or a photothermographic material formed by the method described in 5.
[0014]
7. 7. An image forming method, wherein the exposure is performed by an exposure apparatus in which an angle formed by the scanning laser beam and the exposure surface of the photothermographic material described in 6 is not substantially perpendicular.
[0015]
8). 5. The photothermographic material described in 6 above contains 5 to 1000 mg / m of solvent.²An image forming method comprising heat-developing in a contained state.
[0016]
9. 7. An image forming method, wherein the protective layer of the photosensitive material described in 6 and a heated drum are brought into contact with each other for development.
[0017]
The production of the organic silver salt is described in the above-mentioned patents and the like, but there is a problem that the dispersion becomes highly viscous at the time of preparing the organic silver salt as described above, and it is difficult to prepare a uniform organic silver salt. It has become a problem.
[0018]
Therefore, a method capable of producing a uniform organic silver salt even in a medium having a relatively high viscosity as described above is desired.
[0019]
In addition, there is a great influence on the basic characteristics such as developability and fog characteristics of the photothermographic material using this, and for example, the photographic characteristics are that the organic silver salt has a fine and uniform particle size. preferable. In particular, as a silver ion source by heat development, the organic silver salt must be dissolved quickly and supply silver ions to the development site. If large particles that take time to dissolve are mixed, the progress of development is delayed. For this reason, it is not preferable in a thermal development system in which a development reaction and a fogging reaction are competitive. The organic silver salt once prepared is separately dispersed and pulverized and used after finely grading the particle size, but for this purpose, the dispersion time becomes longer even if a high shearing force disperser or mixer is used. It is important to obtain uniform organic silver salt particles when preparing the silver salt.
[0020]
In view of the above circumstances, as a result of intensive studies on a method for preparing an organic silver salt having a uniform particle size and a small number of coarse particles, especially a long-chain fatty acid silver, the above object of the present invention is achieved by the above manufacturing method and manufacturing apparatus. The inventors have found that this is achieved.
[0021]
As described above, as a method for preparing an organic silver salt dispersion in an aqueous solution, generally an organic fatty acid is dissolved in water at a melting point or higher and reacted with an alkali hydroxide to obtain an organic acid alkali metal salt. Thereafter, a method is known in which a silver halide emulsion is added, and a water-soluble silver salt is further added to form an organic silver salt dispersion.
[0022]
In these methods, an organic acid alkali metal, which is an organic silver salt-forming component, or an organic acid component, such as an ammonium salt, and a water-soluble silver salt, for example, a component such as silver nitrate, are locally inhomogeneous. It is necessary to eliminate For this reason, it is necessary to quickly consume two components (or one component in the case of a single jet) and to prevent local accumulation of unreacted components.
[0023]
This requires quick mixing of the reaction components and the added reaction components need to be mixed immediately.
[0024]
Therefore, rather than adding the reaction component to the liquid surface, it is necessary to add it in the liquid, in the vicinity of the agitator and mixer. The added ingredients are immediately mixed and reacted here. Even in normal stirring, vortexes are usually formed in the liquid and stirred, but the reaction component addition port needs to be located in the vicinity of the stirring member so as to be caught in the vortex. It means that. This effect is particularly great when the viscosity of the reaction medium is high.
[0025]
Since these vortex flows are weak in a normal stirrer, if the present invention is to be carried out more effectively, a stronger vortex flow such as a high-speed centrifugal radiant stirrer (dissolver mixer) is generated and the components are involved. Those are preferred. In this method, a toothed disk-shaped impeller, in which circular saw blades are alternately bent up and down, is rotated at a high speed to generate a vortex. Since the generated powder and each component of the reaction are strongly entrained by this vortex, the reaction is performed more uniformly and the shearing force is strong, so that it is effective for dispersing the resulting powder.
[0026]
More preferably, a high-speed rotating shear type stirrer is used, which not only rotates the unit stirring blade at a high speed but also combines a stationary ring (stater) so as not to cause excessive cavitation in the vicinity of the outer periphery of the stirring blade. Is used. In this case, the strong shearing effect and impact that occur between the rotor blade and the stationary ring can be used, and the strong axial flow along the rotation axis of stirring is formed, so the nucleation of organic silver salt particles is short. Since the reaction is performed along the axial flow efficiently in time, the reaction proceeds more uniformly. Also, the axial flow 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. In any of these stirring operations, the reaction component addition port is provided in the vicinity of the stirring blade (that is, the position where the reaction component is sucked into the vortex).
[0027]
The reaction component addition port may have any shape as long as it does not interfere with the above effects, and may be a simple nozzle or a nozzle having a porous tip.
[0028]
In the present invention, for example, in the case of the double jet system, two addition ports for adding two components at the same time in the vicinity of the stirring blade, and one component of the reaction are placed in a reaction vessel. When the other component is mixed, it can also be carried out with one addition port for supplying the component to be added in the vicinity of the stirring blade.
[0029]
In addition, the present invention is preferably carried out with a combination of various stirring blades as described above to enhance the above effects, and in the reaction vessel at the same time as using a high-speed rotary stirrer provided with an addition nozzle in the vicinity. It is preferable to use at least another auxiliary stirrer in order to ensure the uniformity of the whole. For example, the reaction component is supplied to the vicinity of the high-speed rotating centrifugal radiation type stirrer or more preferably the high-speed rotating shear type stirrer, and the reaction is performed, while the uniformity of the entire container is sufficiently ensured, for example. It is preferable to combine a stirrer having, for example, a propeller blade or a turbine blade. The stirrer used for this assistance is intended to ensure the uniformity of the reaction system, and varies depending on the shape and size of the reaction vessel. When using a large reaction vessel as will be described later, in addition to a simple propeller blade in addition to an auxiliary stirrer for efficiently stirring the entire reaction vessel, use a combination of a high-speed rotary centrifugal radiation type agitator, etc. Also good.
[0030]
Examples of the high-speed rotary shear type stirrer particularly preferably used in the present invention include the following. T.A. K. Combimix (manufactured by Koki Kogyo Kogyo Co., Ltd.), Satake Hybrid Mixer (manufactured by Satake Chemical Machinery Co., Ltd.), vacuum emulsification stirring device (manufactured by Mizuho Kogyo Co., Ltd.), vacuum emulsification dispersion device Frimix (manufactured by Shinko Pantech Co., Ltd.) )etc.
[0031]
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.
[0032]
In FIG. 1, in the reaction tank 1 in which a jacket kettle 6 for maintaining heating, cooling and reaction temperature during the reaction is installed, non-uniformity due to the stagnation of the reaction solution particularly near the wall of the container is prevented. For this purpose, an anchor blade 2 that is usually used with a slower rotation than the stirring blade for reaction is installed. A stirring blade for carrying out the reaction of the present invention is represented by a homomixer 5 which is a high-rotation shear type stirring device. This is because the axial flow along the rotation axis of the homomixer 5 is formed from the bottom to the top of the stirring blade in this case._ThreeAn aqueous solution addition nozzle 4 is provided immediately below the stirring blade in the immediate vicinity of the homomixer 5. A silver nitrate aqueous solution is supplied through the nozzle 4 from the immediate vicinity of the homomixer 5 to another reaction component such as an organic acid alkali metal salt in the reaction tank, and the mixture is uniformly mixed and reacted through the high rotation shear type agitator homomixer 5. Since the axial flow generated in this case also increases the efficiency of stirring in the vertical direction, more uniform production is possible.
[0033]
An enlarged view of the homomixer portion is shown in FIG. 1, but the structure is such that a stirring blade 7 that rotates at high speed by a rotating shaft 9 that rotates at high speed and a stationary ring 8 (stator) provided on the outer periphery of the stirring blade are combined. It has become. Reference numeral 10 shows how the axial flow is generated.
[0034]
In addition, this manufacturing apparatus is provided with a separate high-speed rotating centrifugal radiation type agitator dissolver 3, which is a large reaction tank in which it is difficult to ensure uniformity in the reaction tank only with anchor blades. This is also to eliminate the local concentration of the reaction component when used. The use of a high-speed rotating centrifugal radial stirrer improves the uniformity of the reaction system through the formation of vortex flow. In the above apparatus, M represents a motor for each stirrer.
[0035]
The peripheral speed of the anchor blade is preferably 0.1 m / sec to 10 m / sec, more preferably 0.1 m / sec to 1.5 m / sec, and particularly preferably 0.1 m / sec to 3 m. / Sec.
[0036]
Further, the peripheral speed of the stirring member of the above-described disperser or homomixer is preferably 1 m / sec to 100 m / sec, more preferably 1 m / sec to 15 m / sec, and particularly preferably 1 m / sec to 30 m / sec.
[0037]
The organic silver salt is used for a photothermographic material. The produced organic silver salt particles are filtered and dried or separated by an appropriate method, for example, agglomerated and washed, and then washed with a binder such as polyvinyl butyral used in a photothermographic material instead of water. Dispersed in organic solvent solution. Before and after that, if necessary, it is dispersed again by various media type dispersers such as a ball mill and a sand mill, and various homogenizers such as a colloid mill, and then various components constituting the photothermographic material such as silver halide and halogenation formation. Ingredients, reducing agents, toning agents and the like are mixed and applied onto a base such as polyethylene terephthalate or a paper support, and a protective film is usually applied thereto to form a photothermographic material.
[0038]
The organic silver salt produced by the method and production apparatus of the present invention has high developability and low fog due to the uniform fine particles and particle size, and exhibits favorable characteristics in terms of photographic characteristics.
[0039]
To prepare an organic silver salt dispersion in an aqueous solution, the organic fatty acid is dissolved in water above its melting point as described above, and then reacted with alkali hydroxide, and then the silver halide emulsion is added when the temperature is lowered. Further, a method is known in which a water-soluble silver salt is further added to form an organic silver salt dispersion. For example, it is known that silver behenate prepared by the above method using behenic acid as an organic acid has a part of free behenic acid. Usually, it is preferable that the concentration of the free organic acid is kept constant. When the organic acid concentration is high, the devitrification property of the photothermographic layer is deteriorated. Therefore, particularly in the case of a photosensitive material having a photothermographic layer on the base, the ratio of the free organic acid is set low. Accordingly, in order to keep the content ratio on the left constant and to give a high image density, the organic silver salt is usually prepared with an excess of silver nitrate in order to produce an organic acid silver salt.
[0040]
According to the method and apparatus of the present invention, since the mixing efficiency is improved, the reaction efficiency between the organic acid and silver nitrate is improved, and the organic acid content of the produced organic silver salt is also stabilized at a constant level. Therefore, an organic silver salt having a low organic acid content can be obtained even in an organic silver salt produced by a formulation having a lower ratio of silver nitrate than an organic acid, and this can be used to produce a sufficiently high concentration of heat. A development photosensitive material can be obtained. Further, the amount of silver ions remaining without reacting is reduced, and a favorable effect that fog is reduced also in the characteristics of the photothermographic material containing an organic silver salt obtained by using this method. This seems to be due to a decrease in the amount of excess silver that was not used for the reaction contained in the photosensitive material. Also, from the viewpoint of the waste liquid at the time of preparing the organic silver salt, the amount of silver ions to be discharged is reduced, which is preferable from the viewpoint of wastewater treatment load and reduction in the number of washing steps. According to this reactor, 0.9 to 0.97 mole of silver nitrate per mole of organic acid is added and reacted to achieve sufficient conversion to an organic silver salt. An organic silver salt with a lower concentration of residual organic acid having a higher concentration than that obtained is obtained.
[0041]
A manufacturing apparatus having a plurality of stirring members, a member that performs stirring along the inner wall or the bottom, at least one high-speed stirring member that rotates at a high speed, and the vicinity of the high-speed stirring member, which are preferable embodiments of the above-described apparatus of the present invention In the case of using an apparatus for producing an organic acid silver salt dispersion characterized by a production apparatus equipped with a nozzle for adding a water-soluble silver salt, the above effect is significant, and the production apparatus of the present invention described in FIG. 1 was used. In particular, the effect is large and preferable.
[0042]
Details of the photothermographic material using the organic silver salt produced by the method and apparatus of the present invention will be described below.
[0043]
In the present invention, the organic silver salt is a reducible silver source as described above, and silver salts of organic acids and heteroorganic acids containing a reducible silver ion source, particularly long chains (10-30, preferably 15- An aliphatic carboxylic acid having 25 carbon atoms) and a nitrogen-containing heterocyclic ring are preferred. Also useful are organic or inorganic silver salt complexes in which the ligand has a total stability constant for silver ions of 4.0-10.0. Examples of suitable silver salts are described in Research Disclosure (hereinafter abbreviated as RD) 17029 and 29963, and include the following: silver salts of organic acids (eg, gallic acid, oxalic acid, behenic acid, arachidin) Acid, stearic acid, palmitic acid, silver salt such as lauric acid); silver carboxyalkylthiourea salt (for example, 1- (3-carboxypropyl) thiourea, 1- (3-carboxypropyl) -3,3-dimethylthio Silver salt of urea); silver complex of polymer reaction product of aldehyde and hydroxy-substituted aromatic carboxylic acid (for example, aldehydes (formaldehyde, acetaldehyde, butyraldehyde, etc.) and hydroxy-substituted acids (for example, salicylic acid, benzoic acid, 3 , 5-dihydroxybenzoic acid, 5,5-thiodisalicylic acid) Product silver complexes; silver salts or complexes of thioenes such as 3- (2-carboxyethyl) -4-hydroxymethyl-4-thiazoline-2-thioene, and 3-carboxymethyl-4-thiazoline-2- A silver salt or complex of thioene); a nitrogen acid selected from imidazole, pyrazole, urazole, 1,2,4-thiazole and 1H-tetrazole, 3-amino-5-benzylthio-1,2,4-triazole and benzotriazole And silver complexes and salts; silver salts such as saccharin and 5-chlorosalicylaldoxime; and silver salts of mercaptides.Preferred silver sources are silver behenate, silver arachidate and / or silver stearate.
[0044]
As described above, an organic silver salt compound is usually prepared by dissolving an organic fatty acid in water at the melting point or higher, allowing it to react with alkali hydroxide, and then adding an emulsion when the temperature is lowered, and further adding a water-soluble silver salt. It is known that organic silver salts obtained by these methods partially contain free organic acids. In order to produce an organic silver salt that keeps this content ratio constant and gives a high image density, silver nitrate is usually prepared in an excess state according to conventional methods. In the case of an organic silver salt containing an excessive amount of organic acid, devitrification problems may occur. Therefore, when preparing a stable organic silver salt having a low organic acid content in the organic silver salt, In order to obtain a high salt reaction rate, an organic silver salt is prepared using an excessive amount of silver nitrate.
[0045]
In the case of preparing an organic silver salt using the apparatus of the present invention, the reaction efficiency of the organic silver salt formation reaction is good, and the added silver nitrate is sufficiently converted to an organic silver salt. It has been found that an organic silver salt that provides a stable high image density can be produced. Further, since silver ions remaining in the photosensitive material as a washing residue cause fogging, there arises an advantage that fogging of the photothermographic material prepared from this is reduced. Since excess silver ions that have not been used in the reaction are small, they can be easily removed by washing, and there is also an advantage that extra silver ions that are discarded are reduced.
[0046]
In the present invention, the organic silver salt preferably has an average particle size of 2 μm or less and is monodispersed. The average particle diameter of the organic silver salt refers to the diameter when a sphere equivalent to the volume of the organic silver salt particle is considered when the organic silver salt particle is, for example, a spherical, rod-like, or tabular particle. The average particle diameter is preferably 0.05 μm to 1.5 μm, particularly preferably 0.05 μm to 1.0 μm. Moreover, monodispersion is synonymous with the case of silver halide, Preferably monodispersion degree is 1-30.
[0047]
After the organic silver is prepared, the organic silver crystal can be obtained by dispersing and grinding a binder, a surfactant or the like with a ball mill or the like. By setting it within this range, a photosensitive material having a high density and excellent image storability can be obtained.
[0048]
In the present invention, the organic silver salt is a support 1 m.²It is used in the range of 0.1 g to 4 g, preferably 0.2 g to 2.5 g in terms of the amount of silver per hit. This is a range of an amount necessary and sufficient to give an appropriate density, and if it is less than this range, the image density will be insufficient, and if it is used more than this density, the image density will not increase, and the cost will be increased. Become.
[0049]
The silver halide grains function as an optical sensor, and in order to suppress white turbidity after image formation, and to obtain good image quality, it is preferable that the average grain size is small, the average grain size is 0.1 μm or less, More preferably, it is 0.01 μm to 0.1 μm, particularly 0.02 μm to 0.08 μm. The grain size here refers to the length of the edge of the silver halide grain when the silver halide grain is a so-called normal crystal of a cube or octahedron. In the case of non-normal crystals, for example, in the case of spherical, rod-like or tabular grains, it means the diameter when a sphere equivalent to the volume of silver halide grains is considered. The silver halide is preferably monodispersed. The monodispersion here means that the monodispersity obtained by the following formula is 40 or less. More preferred is a particle of 30 or less, and particularly preferred is a particle of 0.1% or more and 20% or less.
[0050]
Monodispersity = (standard deviation of particle size) / (average value of particle size) × 100
The shape of the silver halide grains is not particularly limited, but the ratio occupied by the Miller index [100] plane is preferably high, and this ratio is 50% or more, further 70% or more, particularly 80% or more. Is preferred. The ratio of the Miller index [100] plane is calculated by using the adsorption dependency between the [111] plane and the [100] plane in the adsorption of the photosensitive dye. Tani, J .; Imaging Sci. 29, 165 (1985).
[0051]
Another preferred silver halide shape is tabular grains. The tabular grains referred to here are those having an aspect ratio = r / h of 3 or more when the square root of the projected area is the grain size r μm and the thickness in the vertical direction is h μm. Among them, the aspect ratio is preferably 3 or more and 50 or less. Moreover, it is preferable that a particle size is 0.1 micrometer or less, Furthermore, 0.01 micrometer-0.08 micrometer are preferable. These are described in US Pat. Nos. 5,264,337, 5,314,798, 5,320,958, etc., and the desired tabular grains can be easily obtained. When these tabular grains are used in the present invention, the sharpness of the image is further improved. 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.
[0052]
The photographic emulsion used in the present invention is P.I. Chifie et Physique Photographic (published by Paul Montel, 1967) by Glafkides. F. Duffin's Photographic Emission Chemistry (published by The Focal Press, 1966), V.C. L. It can be prepared using the method described in Making and Coating Photographic Emulsion (published by The Focal Press, 1964) by Zelikman et al. That is, any of an acidic method, a neutral method, an ammonia method, etc. may be used, and the formation of reacting a soluble silver salt and a soluble halogen salt may be any one of a one-side mixing method, a simultaneous mixing method, and a combination thereof. Good. The silver halide may be added to the image forming layer by any method, and at this time, the silver halide is disposed in the vicinity of the reducible silver source. Further, the silver halide may be prepared by converting a part or all of silver in the organic acid silver to silver halide by the reaction between the organic acid silver and the halogen ion, or the silver halide is prepared in advance. This may be added to the solution for preparing the organic silver salt, or a combination of these methods is possible, but the latter is preferred. In general, the silver halide is preferably contained in an amount of 0.75 to 30% by weight based on the organic silver salt.
[0053]
The silver halide used in the present invention preferably contains ions of transition metals belonging to groups 6 to 10 of the periodic table of elements in order to improve illuminance failure and to make adjustments. The above metals are preferably W, Fe, Co, Ni, Cu, Ru, Rh, Pd, Re, Os, Ir, Pt, and Au. These metal ions are obtained by introducing a metal salt into silver halide as it is. However, it can be introduced into the silver halide in the form of a metal complex or complex ion. As these transfer metal complexes and metal complex ions, hexacoordinate complex ions represented by the following general formula are preferable.
[0054]
General formula [ML₆]^m
In the formula, M represents a transition metal selected from Group 6 to 10 elements of the periodic table, L represents a bridging ligand, and m represents 0, 1-, 2-, 3-, or 4-. Specific examples of the ligand represented by L include halides (fluoride, chloride, bromide and iodide), cyanide, cyanate, thiocyanate, selenocyanate, tellurocyanate, azide and aco. A ligand, nitrosyl, thionitrosyl and the like can be mentioned, and ako, nitrosyl, thionitrosyl and the like are preferable. When an acoligand is present, it preferably occupies one or two of the ligands. L may be the same or different.
[0055]
Specific preferred examples of M are rhodium (Rh), ruthenium (Ru), rhenium (Re), iridium (Ir) and osmium (Os).
[0056]
Specific examples of transition metal coordination complex ions are shown below.
[0057]
1: [RhCl₆]^3-
2: [RuCl₆]^3-
3: [ReCl₆]^3-
4: [RuBr₆]^3-
5: [OsCl₆]^3-
6: [IrCl₆]^Four-
7: [Ru (NO) Cl_Five]^2-
8: [RuBr_Four(H₂O)]^2-
9: [Ru (NO) (H₂O) Cl_Four]^-
10: [RhCl_Five(H₂O)]^2-
11: [Re (NO) Cl_Five]^2-
12: [Re (NO) (CN)_Five]^2-
13: [Re (NO) Cl (CN)_Four]^2-
14: [Rh (NO)₂Cl_Four]^-
15: [Rh (NO) (H₂O) Cl_Four]^-
16: [Ru (NO) (CN)_Five]^2-
17: [Fe (CN)₆]^3-
18: [Rh (NS) Cl_Five]^2-
19: [Os (NO) Cl_Five]^2-
20: [Cr (NO) Cl_Five]^2-
21: [Re (NO) Cl_Five]^-
22: [Os (NS) Cl_Four(TeCN)]^2-
23: [Ru (NS) Cl_Five]^2-
24: [Re (NS) Cl_Four(SeCN)]^2-
25: [Os (NS) Cl (SCN)_Four]^2-
26: [Ir (NO) Cl_Five]^2-
27: [Ir (NS) Cl_Five]^2-
28: [IrCl₆]^2-
One kind of these metal complexes or complex ions may be used, or two or more kinds of the same and different metals may be used in combination.
[0058]
The content of these metal ions, metal complexes and complex ions is generally 1 × 10 5 per mole of silver halide.^-9~ 1x10^-2Molar is suitable, preferably 1 × 10^-8~ 1x10^-FourIs a mole. The compounds providing these metal ions or complex ions are preferably added at the time of silver halide grain formation and incorporated into the silver halide grains. Preparation of silver halide grains, that is, nucleation, growth, physical ripening , May be added at any stage before or after chemical sensitization, but is preferably added at the stage of nucleation, growth and physical ripening, more preferably at the stage of nucleation and growth, most preferably Preferably, it is added at the stage of nucleation. In addition, it may be divided and added several times, or it can be uniformly contained in the silver halide grains. JP-A-63-29603, JP-A-2-306236, 3 As described in JP-A Nos. 167545, 4-76534, 6-110146, 5-273683, etc., it can be contained in a particle with a distribution. These metal compounds can be added by dissolving in water or an appropriate organic solvent (for example, alcohols, ethers, glycols, ketones, esters, amides). A method in which an aqueous solution or an aqueous solution in which a metal compound and NaCl, KCl are dissolved together is added to a water-soluble silver salt solution or a water-soluble halide solution during particle formation, or the silver salt solution and the halide solution are mixed simultaneously. When adding a third aqueous solution, a method of preparing silver halide grains by a method of simultaneous mixing of three liquids, a method of introducing an aqueous solution of a required amount of a metal compound into a reaction vessel during grain formation, or a silver halide preparation There is a method of adding and dissolving another silver halide grain that has been previously doped with metal ions or complex ions. In particular, a method of adding an aqueous solution of a metal compound powder or an aqueous solution in which a metal compound and NaCl, KCl are dissolved together is added to the water-soluble halide solution. When added to the particle surface, a necessary amount of an aqueous solution of a metal compound can be charged into the reaction vessel immediately after the formation of the particle, during or after the physical ripening, or at the chemical ripening.
[0059]
The photosensitive silver halide grains can be desalted by washing with water known in the art, such as a noodle method or a flocculation method, but in the present invention, it may or may not be desalted.
[0060]
The photosensitive silver halide grains in the present invention are preferably chemically sensitized. Preferred chemical sensitization methods are sulfur sensitization, selenium sensitization, tellurium sensitization, noble metal sensitization methods such as gold compounds, platinum, palladium, and iridium compounds, as well known in the art, and reduction sensitization. Sensitive methods can be used. As the compound preferably used in the sulfur sensitization method, selenium sensitization method and tellurium sensitization method, known compounds can be used, but compounds described in JP-A-7-128768 can be used. Compounds preferably used for the noble metal sensitization include, for example, chloroauric acid, potassium chloroaurate, potassium aurithiocyanate, gold sulfide, gold selenide, US Pat. No. 2,448,060, British Patent 618,061, etc. Can preferably be used. As specific compounds of the reduction sensitization method, for example, stannous chloride, aminoiminomethanesulfinic acid, hydrazine derivatives, borane compounds, silane compounds, polyamine compounds, etc. can be used in addition to ascorbic acid and thiourea dioxide. . Further, reduction sensitization can be performed by ripening the emulsion while maintaining the pH at 7 or higher or the pAg at 8.3 or lower. Further, reduction sensitization can be performed by introducing a single addition portion of silver ions during grain formation.
[0061]
Examples of the reducing agent used in the photothermographic material of the invention include generally known reducing agents such as phenols, polyphenols having two or more phenol groups, naphthols, bisnaphthols, and two. Polyhydroxybenzenes having the above hydroxyl groups, polyhydroxynaphthalenes having two or more hydroxyl groups, ascorbic acids, 3-pyrazolidones, pyrazolin-5-ones, pyrazolines, phenylenediamines, hydroxylamines, hydroquinone mono Ethers, hydroxamic acids, hydrazides, amide oximes, N-hydroxyureas and the like, and more specifically, for example, U.S. Pat. Nos. 3,615,533, 3,679,426, 3,672,904, 3,751,252, 3,78 No. 949, No. 3,801,321 No. 3,794,488 No. 3,893,863 No. 3,887,376 No. 3,770,448 3,819,382, 3,773,512, 3,839,048, 3,887,378, 4,009,039, 4,021, No. 240, British Patent No. 1,486,148 or Belgian Patent No. 786,086 and JP-A-50-36143, No. 50-36110, No. 50-11623, No. 50-99719, There are reducing agents specifically exemplified in JP-A-50-140113, JP-A-51-51933, JP-A-51-23721, JP-A-52-84727, and JP-B-51-35851. Of known reducing agents It can be appropriately selected for use from. As the selection method, the simplest method is to examine the superiority or inferiority of the reducing agent used by actually producing a photothermographic material and evaluating its photographic performance.
[0062]
Among the above reducing agents, when an aliphatic carboxylic acid silver salt is used as the organic silver salt, a preferable reducing agent is a polyphenol 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 an acyl group (for example, an acetyl group, a propionyl group, etc.) is substituted at at least one position adjacent to the hydroxy substitution position of Polyphenols in which two or more of the phenol groups are linked by an alkylene group or sulfur, such as 1,1-bis (2-hydroxy-3,5-dimethylphenyl) -3,5,5-trimethylhexane, 1,1- Bis (2-hydroxy-3-tert-butyl-5-methylphenyl) methane, 1,1-bis (2-hydroxy-) , 5-Di-tert-butylphenyl) methane, 2-hydroxy-3-tert-butyl-5-methylphenyl)-(2-hydroxy-5-methylphenyl) methane, 6,6′-benzylidene-bis (2 , 4-di-tert-butylphenol), 6,6′-benzylidene-bis (2-tert-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, US Pat. Nos. 3,5 such as 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane and 2,2-bis (4-hydroxy-3,5-di-t-butylphenyl) propane No. 9,903, No. 4,021,249 or British Patent No. 1,486,148 and JP-A-51-51933, No. 50-36110, No. 50-11603, No. 52- Polyphenol compounds described in US Pat. No. 84727 or JP-B-51-35727), bisnaphthols described in US 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 further described in US Pat. No. 3,801,321. Sulfonamidophenols or sulfonamidonaphthols such as 4-benzenesulfonamidophenol, 2-benzenesulfonamidophenol, 2,6-dichloro-4-benzenesulfonamidophenol, 4-benzenesulfonamidonaphthol, etc. Can be mentioned.
[0063]
The amount of the reducing agent used in the photothermographic material of the present invention varies depending on the type of organic silver salt, reducing agent, and other additives, but generally 0.05 mol to 1 mol per mol of organic silver salt. 10 mol, preferably 0.1 mol to 3 mol is appropriate. In addition, within the range of this amount, two or more of the reducing agents described above may be used in combination.
[0064]
In the photothermographic material of the present invention, it is desirable to use an additive (hereinafter referred to as a color tone agent) called a color tone, a color tone imparting agent or an activator toner together with the above-described components. The toning 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. As the color toning agent, various compounds are already known, but most of them are compounds having an imino group, a mercapto group or a thione group. An appropriate colorant may be selected from among the organic silver salt and reducing agent used. Examples of the color tone agent that gives a preferable color tone effect in the photothermographic material of the present invention include phthalazinones (for example, phthalazinone, 2-acetylphthalazinone, 2-carbamoylphthalazinone), and 2-pyrazolin-5-ones (for example, 3-methyl-2-pyrazolin-5-one etc.), quinazolines (eg quinazoline, 4-methylquinazoline etc.), pyrimidines (eg 6-methyl-2,4-dihydroxypyrimidine etc.), 1,2,5- Triazines (such as 3-methyl-4,6-dihydroxy-1,2,5-triazine), phthalazinediones (such as phthalazinedione), cyclic imides (such as succinimides, phthalimides, urazoles), Heterocyclic compounds having an imino group such as benzoxazinediones and naphthalimides) . These colorants may be used in combination of two or more. For example, as described in JP-A Nos. 53-1020 and 53-55115, benzoxazinediones and benzothiazinediones are combined with phthalazinone. In combination with phthalimides or phthalimides, it is possible to prevent deterioration of the color tone effect resulting from storage under high temperature and high humidity.
[0065]
Further, as described in U.S. Pat. Nos. 3,847,612 and 3,994,732, phthalic acid, naphthoic acid or phthalamic acid and imidazoles or phthalazines are used as a color toning agent. It can also be used.
[0066]
When using a color toning agent, the amount used is preferably in the range of 0.0001 mol to 2 mol, particularly 0.0005 mol to 1 mol, per mol of the organic silver salt.
[0067]
The photothermographic material of the present invention may contain an antifoggant. Examples of effective antifoggants include 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 antifoggants as disclosed in U.S. Pat. Nos. 4,546,075 and 4,452,885 and JP-A-59-57234.
[0068]
Particularly preferred non-mercury antifoggants are compounds such as those disclosed in U.S. Pat. Nos. 3,874,946 and 4,756,999, -C (X₁) (X₂) (X_Three) (Where X₁And X₂Is a halogen atom and X_ThreeIs 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 paragraphs [0030] to [0036] of JP-A-9-288328.
[0069]
Another example of the antifoggant is a compound described in paragraph Nos. [0062] to [0063] of JP-A-9-90550. In addition, other suitable antifoggants are disclosed in US Pat. No. 5,028,523 and European Patent Nos. 600,587, 605,981 and 631,176.
[0070]
Examples of the photothermographic material of the present invention include JP-A-63-159841, JP-A-60-140335, JP-A-63-231437, JP-A-63-259651, JP-A-63-304242, and JP-A-63-15245. Nos. 4,639,414, 4,740,455, 4,741,966, 4,751,175, and 4,835,096. Can be used. Useful sensitizing dyes used in the present invention are described, for example, in the literature described or cited in Section RD17643 IV-A (December 1978, p. 23). In particular, a sensitizing dye having spectral sensitivity suitable for the spectral characteristics of various scanner light sources can be advantageously selected. For example, for an argon ion laser light source, see JP-A-60-162247, JP-A-2-48635, US Pat. No. 2,161,331, West German Patent 936,071, JP-A-5-11389, etc. For the simple merocyanines and helium neon laser light sources described, trinuclear cyanine dyes disclosed in JP-A-50-62425, JP-A-54-18726, and JP-A-59-102229, JP-A-7-287338. Nos. 48-42172, 51-9609, 55-39818, JP-A-62-284343, JP-A-2-28443, and the like. JP-A-59-191032, JP-A-59-191032, JP-A-59-191032 and the thiacarbocyanines described in 105135 Tricarbocyanines described in 0-80841, dicarbocycles containing 4-quinoline nuclei described in general formulas (IIIa) and (IIIb) of JP-A-59-192242 and JP-A-3-67242 Cyanines and the like are advantageously selected. Further, in the case where the wavelength of the infrared laser light source is 750 nm or more, more preferably 800 nm or more, Japanese Patent Application Laid-Open Nos. 4-18239, 5-341432, and 7-13295 disclose such a wavelength region. No. 6-52387, JP-A-3-10931, US Pat. No. 5,441,866 and the like are preferably used.
[0071]
These sensitizing dyes may be used alone, and the combination of sensitizing dyes is often used for the purpose of supersensitization. Along with the sensitizing dye, the emulsion itself may contain a dye having no spectral sensitizing action or a substance that does not substantially absorb visible light and exhibits supersensitization. For the exposure of the photothermographic material of the present invention, an argon ion laser (488 nm), a He—Ne laser (633 nm), a red semiconductor laser (670 nm), an infrared semiconductor laser (780 nm, 820 nm) or the like is preferably used. An infrared semiconductor laser is more preferably used from the viewpoint that the power is high power and the photosensitive material can be transparent.
[0072]
In addition, printout inhibitors and various additives that prevent discoloration due to printout of unexposed areas after heat development processing, such as surfactants, antioxidants, stabilizers, plasticizers, UV absorbers, coatings Auxiliaries and the like may be used in the photothermographic material of the present invention, and the compounds described in RD17029 (June 1978, p.9-15) are preferably used as these additives and the other additives described above. be able to. These additives may be added to any one of the heat-developable photosensitive layer, the non-photosensitive layer, and other layers.
[0073]
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, Polyvinyl pyrrolidone, polymethyl methacrylate, polyvinyl chloride, copoly (styrene-maleic anhydride), copoly (styrene-acrylonitrile), copoly (styrene-butadiene), polyvinyl acetals such as polyvinyl formal, polyvinyl butyral, polyvinyl acetates, There are water-insoluble polymers such as cellulose esters. However, among these binders, water-insoluble polymers such as cellulose acetate, cellulose acetate butyrate, and polyvinyl butyral are particularly preferable, and polyvinyl butyral is particularly preferable.
[0074]
In the present invention, the binder amount of the photosensitive layer is 1.5 to 6 g / m.²It is preferable that More preferably 1.7 to 5 g / m²It is. 1.5g / m²If it is less than 1, the density of the unexposed area will be significantly increased, and it may be unusable.
[0075]
Each component used in the photothermographic material of the present invention is dispersed in at least one colloid as a binder. Examples of suitable binders include the above-described hydrophobic polymer materials. As described above, polyvinyl butyral is most preferable as the binder used in the photosensitive layer. If necessary, two or more of these polymer materials may be used in combination. The polymer material is used in an amount sufficient to support the component 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, when at least an organic silver salt is dispersedly supported, the weight ratio with respect to the organic silver salt is 10: 1 to 1:10, particularly 4: 1 to 1 pair. 4 is used.
[0076]
The composition containing each component of the photothermographic material of the present invention is usually applied in the state of being supported on the binder and divided into one layer or two or more layers on various supports selected from a wide range of materials. Is done. The material of the support includes various polymer materials, glass, wool cloth, cotton cloth, paper, metal (for example, aluminum), etc., but it is processed into a flexible sheet or roll for handling as an information recording material. What can be done is preferred. Accordingly, the support in the photothermographic material of the present invention is preferably a plastic film (for example, cellulose acetate film, polyester film, polyethylene terephthalate film, polyethylene naphthalate film, polyamide film, polyimide film, cellulose triacetate film or polycarbonate film). As mentioned above, a biaxially stretched polyethylene terephthalate film is particularly preferred in the present invention.
[0077]
The method for applying each layer of the light-sensitive material of the present invention is not particularly limited, and known methods such as a bar coater method, a curtain coating method, a dipping method, an air knife method, and a hopper coating method can be used. More preferably, a pre-weighing type coating method called an extrusion method is preferred.
[0078]
The photosensitive material of the present invention is preferably provided with a protective layer and a backcoat layer in addition to the above-mentioned heat-developable photosensitive layer. If necessary, the heat-developable photosensitive layer may have a two-layer structure having different sensitivities or an intermediate between them. It is possible to provide a layer.
[0079]
As the binder for the protective layer, water-insoluble polymers such as cellulose acetate, cellulose acetate butyrate, and polyvinyl butyral are preferable, and cellulose acetate and cellulose acetate butyrate are particularly preferable.
[0080]
The preferred thickness of the photothermographic layer containing silver halide of the present invention is 0.2 to 40 μm, more preferably 2 to 30 μm per layer.
[0081]
The preferred thickness of the surface protective layer is 0.2 to 10 μm, more preferably 1 to 5 μm per layer.
[0082]
The preferable thickness of the backcoat layer is 0.2 to 10 μm, more preferably 1 to 5 μm per layer.
[0083]
In the present invention, it is advantageous that a small amount of material is contained during the heat development of the photothermographic material. As these solvents, a small amount of a solvent used as a coating solvent for the heat-developable photosensitive layer or protective layer may be left, or a small amount may be added by a method such as separately applying a solvent or spraying. This improves the heat development characteristics and can achieve higher gamma and lower fog, which is preferable.
[0084]
Examples of these solvents include ketones such as acetone, isophorone, ethyl amyl ketone, methyl ethyl ketone, and methyl isobutyl ketone. Examples of alcohols include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, diacetone alcohol, cyclohexanol, and benzyl alcohol. Examples of glycols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, and hexylene glycol. Examples of ether alcohols include ethylene glycol monomethyl ether and diethylene glycol monoethyl ether. Examples of ethers include ethyl ether, dioxane, isopropyl ether and the like. Examples of the esters include ethyl acetate, butyl acetate, amyl acetate, isopropyl acetate and the like. Examples of hydrocarbons include 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 amines include monomethylamine, dimethylamine, triethanolamine, ethylenediamine, and triethylamine. Other examples include water, formamide, dimethylformamide, nitromethane, pyridine, toluidine, tetrahydrofuran, and acetic acid. However, it is not limited to these. These solvents can be used alone or in combination of several kinds.
[0085]
The content of the solvent in the photosensitive material can be adjusted by changing conditions such as temperature conditions in the drying step after the coating step. Further, the content of the solvent can be measured by gas chromatography under conditions suitable for detecting the contained solvent.
[0086]
The amount of the solvent contained in the photosensitive material according to the present invention is 1 m of the photosensitive material.²5 to 1000 mg / m in total amount (weight basis)²It is necessary to adjust so that it is.
[0087]
When the content is in the above range, a photothermographic material having a low fog density while having high sensitivity can be obtained.
[0088]
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 formed between the exposure surface of the photosensitive material and the scanning laser beam may be substantially perpendicular. It is preferable to use no laser scanning exposure machine.
[0089]
Here, “substantially non-vertical” is preferably 55 ° to 88 °, more preferably 60 ° to 86 °, and even more preferably 65 ° or more as the angle closest to the vertical during laser scanning. 84 degrees or less, most preferably 70 degrees or more and 82 degrees or less.
[0090]
The beam spot diameter on the exposure surface of the photosensitive material when the laser beam is scanned on the photosensitive material is preferably 200 μm or less, more preferably 100 μm or less. This is preferable in that the smaller the spot diameter, the smaller the angle of deviation of the laser incident angle from the vertical. The beam spot diameter is 10 μm. By performing such laser scanning exposure, it is possible to reduce image quality deterioration related to reflected light such as generation of interference fringe-like unevenness.
[0091]
The exposure in the present invention is also preferably performed using a laser scanning exposure machine that emits scanning laser light that is a vertical multi. Compared with a single longitudinal mode scanning laser beam, image quality degradation such as generation of interference fringe-like unevenness is reduced.
[0092]
In order to make a vertical multiplex, methods such as using return light by combining and applying high-frequency superposition are preferable. Note that 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.
[0093]
By these writing means, an image with little unevenness and good sharpness can be obtained.
[0094]
The development conditions of the photothermographic material of the present invention vary depending on the composition, configuration, structure, etc. of the material used. Typically, the photosensitive material is heated at a temperature suitable for this after exposure. Do by. 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). As a result, a silver image 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, white titanium, or the like. Among these, the method of carrying out heat development while contacting the heat roller is preferable from the viewpoint of thermal efficiency and workability.
[0095]
In addition, it is preferable to heat the photothermographic material from the protective layer side in terms of heat transfer efficiency, and it is possible to avoid disadvantages such as uneven heating due to heating from the support side and time required for heat transfer.
[0096]
As a result, a high-quality silver image can be obtained with only complete heating.
[0097]
Hereinafter, the present invention will be described specifically by way of examples.
[0098]
【Example】
Example 1
<Production of support>
Concentration of 0.170 (Konica Densitometer PDA-65) colored blue, 8 W / m on both sides of a 175 μm thick PET film²・ Corona discharge treatment was performed for a minute.
[0099]
<Preparation of photosensitive silver halide emulsion A>
After dissolving 7.5 g of ossein gelatin having an average molecular weight of 100,000 and 10 mg of potassium bromide in 900 ml of water, adjusting the temperature to 35 ° C. and pH to 3.0, 370 ml of an aqueous solution containing 74 g of silver nitrate (98/2) Equimolar ratio of potassium bromide and potassium iodide to silver nitrate and iridium chloride to 1 × 10 5 per mole of silver^-FourWhile maintaining a pAg of 7.7, 370 ml of a molar aqueous solution was added over 10 minutes by the controlled double jet method. Thereafter, 0.3 g of 4-hydroxy-6-methyl-1,3,3a, 7-tetrazaindene was added and the pH was adjusted to 5 with NaOH to obtain an average particle size of 0.06 μm, a particle size variation coefficient of 12%, Cubic silver iodobromide grains having a [100] face ratio of 87% were obtained. The emulsion was coagulated and precipitated using a gelatin flocculant and desalted, and 0.1 g of phenoxyethanol was added to adjust the pH to 5.9 and pAg 7.5 to obtain a photosensitive silver halide emulsion A.
[0100]
<Preparation of organic silver salt A>
An organic silver salt was prepared as follows using the apparatus shown in FIG. 1 modified based on the combination mix SL-10 manufactured by Tokushu Kika Kogyo Co., Ltd.
[0101]
The number of rotations of the anchor blade 2 is 100 rpm, the added number of the dissolver mixer 3 and the homomixer 5 is 1500 rpm, and 4720 ml of pure behenic acid 111.4 g, arachidic acid 83.8 g, and stearic acid 54.9 g are 80 in the reaction vessel. Dissolved at ° C. At that time, the rotation directions of the dissolver mixer 3 and the homomixer 5 were set to be opposite to each other. Next, 540.2 ml of 1.5 M aqueous sodium hydroxide solution was added. Next, 6.9 ml of concentrated nitric acid was added and then cooled to 55 ° C. to obtain an organic acid sodium solution.
[0102]
While maintaining the temperature of the vapor organic acid sodium solution at 55 ° C., the rotation speed of the anchor blade 2 is 100 rpm, the rotation speed of the dissolver mixer 3 and the homomixer 5 is 5000 rpm each, and 780.6 ml of 1M silver nitrate aqueous solution is added to the reaction tank. It added over 2 minutes to the surface of the organic acid sodium. Furthermore, the rotational speeds of the dissolver mixer 3 and the homomixer 5 were each set to 4500 rpm and stirred for 10 minutes to obtain an organic silver salt dispersion.
[0103]
Thereafter, the obtained organic acid silver salt dispersion was transferred to a water-washing container, deionized water was added and stirred, and then allowed to stand to float and separate the organic silver salt dispersion to remove heirloom water-soluble salts. Thereafter, washing with deionized water and drainage were repeated until the electrical conductivity of the drainage reached 2 μS / cm, and after centrifugal dehydration, hot air circulation drying was performed at 40 ° C. until there was no weight loss. Salt A was obtained.
[0104]
<Preparation of organic silver salt B>
In the preparation of the organic silver salt A, the silver nitrate solution was not the surface of the organic acid sodium solution, but instead of AgNOG opened near the homomixer 5 in FIG._ThreeA powdered organic silver salt B was prepared in exactly the same manner except that it was added via the aqueous solution addition nozzle 4.
[0105]
<Preparation of photosensitive emulsion dispersions 1 and 2>
14.57 g of polyvinyl butyral (Monsanto Butvar B-79) was dissolved in 1457 g of methyl ethyl ketone (hereinafter abbreviated as MEK), and 500 g of powdered organic silver salt A was gradually added while stirring with a dissolver type homogenizer and sufficiently mixed. Thereafter, dispersion was performed at a peripheral speed of 13 m and a residence time in the mill of 3 minutes using a media type dispersing machine (gettzmann) filled with 80% of 1 mm diameter Zr beads (manufactured by Toray) to prepare photosensitive emulsion dispersion 1. .
[0106]
Photosensitive emulsion dispersion 2 was obtained in exactly the same manner as in preparation of photosensitive emulsion dispersion 1, except that organic silver salt B was used in place of organic silver salt A.
[0107]
<Preparation of infrared sensitizing dye solution>
350 mg of infrared sensitizing dye 1, 13.96 g of 2-chloro-benzoic acid, and 2.14 g of 5-methyl-2-mercaptobenzimidazole are dissolved in 73.4 ml of methanol in the dark to obtain an infrared sensitizing dye solution. Was prepared.
[0108]
<Preparation of stabilizer solution>
Stabilizer solution was prepared by dissolving 1.0 g of Stabilizer 1 and 0.5 g of potassium acetate in 8.5 g of methanol.
[0109]
<Preparation of developer solution>
As a developer, 17.74 g of 1,1- (2-hydroxy-3,5-dimethylphenyl) -2-methylpropane was dissolved in MEK and finished to 100 ml to obtain a developer solution.
[0110]
<Preparation of antifoggant solution>
Antifoggant 2 was dissolved in 5.81 g of MEK and finished to 100 ml.
[0111]
<< Preparation of photosensitive layer coating solution >>
50 g of the photosensitive emulsion dispersion 1 and 15.11 g of MEK were kept at 21 ° C. with stirring, 390 μl of antifoggant 1 (10% methanol solution) was added, and the mixture was stirred for 1 hour. Further, 889 μl of calcium bromide (10% methanol solution) was added and stirred for 30 minutes.
[0112]
While keeping the temperature at 13 ° C., 13.31 g of polyvinyl butyral (Monsanto Butvar B-79) was added and stirred for 30 minutes, and then the following additives were added at intervals of 15 minutes while further stirring was continued.
[0113]
Phthalazine 305mg
Tetrachlorophthalic acid 102mg
4-methylphthalic acid 137mg
Infrared dye 1 37mg
After adding the above and stirring for 15 minutes,
Antifoggant solution 5.47ml
Developer solution 14.06ml
Desmodur N300
(Movey, aliphatic isocyanate) 1.60 ml of 10% MEK solution
Were sequentially added and stirred to obtain photosensitive layer coating solution 1.
[0114]
The same preparation was made for photosensitive emulsion 2 to prepare photosensitive layer coating solution 2.
[0115]
The following layers were sequentially formed on the support to prepare photosensitive materials 1 and 2 as shown in Table 1. In addition, each drying was performed at 75 degreeC for 5 minutes.
[0116]
[Chemical 1]

[0117]
[Chemical formula 2]

[0118]

<Photosensitive layer side coating>
Photosensitive layer: The amount of silver applied is 2 g / m for each of the above compositions²It applied so that it might become.
[0119]
Surface protective layer: A solution having the following composition was coated on the photosensitive layer.
[0120]

<< Measurement of solvent content in film >>
46.3cm as film area²Was cut into 5 mm pieces, stored in a special vial, sealed with a septum and an aluminum cap, and then set on a headspace sampler HP7694 manufactured by Hewlett-Packard. The gas chromatography (GC) connected to the headspace sampler was a Hewlett-Packard 5971 model equipped with a flame ionization detector (FID) as a detector. As main measurement conditions, headspace sampler heating condition: 120 ° C., 20 minutes, GC introduction temperature: 150 ° C., column: DB-624 manufactured by J & W, temperature increase: 45 ° C., 3 minutes to 100 ° C. (8 ° C./8° C.) Gas chromatogram was obtained. The solvent to be measured is MEK, methanol, and after storing a fixed amount diluted with each butanol of the above solvent in a dedicated vial, using the peak area of the chromatogram obtained by measuring in the same manner as described above. The prepared calibration curve was used to obtain the solvent content in the film.
[0121]
<< Exposure and development process >>
From the emulsion surface side of the photosensitive material produced as described above, exposure by laser scanning was given by an exposure machine using a semiconductor laser having a longitudinal multimode wavelength of 800 nm to 820 nm by high frequency superposition as an exposure source. At this time, an image was formed by setting the angle between the exposure surface of the photosensitive material and the exposure laser beam to 75 degrees. (Note that an image with less unevenness and unexpectedly good sharpness and the like was obtained compared to the case where the angle was 90 degrees.) Thereafter, a protective layer of the photosensitive material using an automatic processor having a heat drum Was subjected to heat development at 110 ° C. for 15 seconds so that the surface of the drum contacted. At that time, exposure and development were performed in a room adjusted to 23 ° C. and 50% RH. The obtained image was evaluated with a densitometer. The measurement result is evaluated by sensitivity (reciprocal of the ratio of the exposure amount giving a density higher by 1.0 than the unexposed portion) and fog. The sensitivity is a relative value with the sensitivity of the photosensitive material 1 being 100, and the fog is an actual measurement It showed in. The results are shown in Table 1.
[0122]
[Table 1]

[0123]
Example 2
Using the same apparatus as that of Example 1, an organic silver salt was prepared as follows.
[0124]
Organic silver salt C: Same as the prescription of organic silver salt A, the silver nitrate addition nozzle was installed on the liquid surface, stirring was performed only with the anchor blade, and the amount of 1M silver nitrate used was 811 ml. The amount of silver nitrate is 3 mol% excess relative to the organic acid.
[0125]
Organic silver salt D: Same as the prescription of organic silver salt A, the silver nitrate addition nozzle was installed on the liquid surface, and the stirring was similarly performed only with the anchor blade, and the amount of 1M silver nitrate used was 717 ml. The amount of silver nitrate is 91 mol% with respect to the organic acid.
[0126]
Organic silver salt E: Same as the prescription of organic silver salt B, the silver nitrate addition nozzle was installed in the vicinity of the homomixer, provided that the amount of 1M silver nitrate used was 747 ml. 95 mol% amount based on organic acid.
[0127]
Organic silver salt F: Same as the formula for organic silver salt E. However, the amount of 1M silver nitrate used was 717 ml. An amount of 91 mol% based on the organic acid.
[0128]
Table 2 shows the results of producing photosensitive materials 3 to 6 using the above organic silver salts B to E in the same manner as in Example 1, and performing exposure and thermal development in the same manner to evaluate the maximum fog density. . However, the maximum density is shown as a relative value when the maximum density of the photosensitive material 3 is 100.
[0129]
[Table 2]

[0130]
It can be seen that the light-sensitive material using the organic silver salt prepared by the method of the present invention has low fog and a high maximum density.
[0131]
【The invention's effect】
The organic silver salt dispersion used for the photothermographic material can be uniformly formed, and a photothermographic material and an image forming method with high sensitivity, low fog and stable performance can be obtained.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an example of an apparatus for producing an organic silver salt dispersion of the present invention.
[Explanation of symbols]
1 reaction tank
2 Anchor wing
3 Dissolver Mixer
4 Additive nozzle
5 Homomixer
6 Jacket pot
7 Stirring blade
8 Fixed ring
9 Rotating shaft
10 Direction of axial flow
M motor

Claims (7)

A method for producing an organic silver salt dispersion in a reaction vessel by adding a water-soluble silver salt to an alkaline salt aqueous solution or suspension of a long chain (10 to 30 carbon atoms ) aliphatic carboxylic acid, In the reaction tank, stirring along the inner wall or bottom and stirring with at least one high-speed stirring member that rotates at high speed are simultaneously performed, and the water-soluble silver salt is added through a nozzle installed in the vicinity of the high-speed stirring member. A method for producing an organic silver salt dispersion characterized by the above. A production apparatus having a reaction tank for forming an organic silver salt dispersion by adding a water-soluble silver salt to an alkaline salt aqueous solution or suspension of a long-chain (10 to 30 carbon atoms ) aliphatic carboxylic acid, The reaction vessel is provided with a member for stirring along the inner wall or bottom, at least one high-speed stirring member that rotates at high speed, and a nozzle for adding a water-soluble silver salt in the vicinity of the high-speed stirring member. An apparatus for producing an organic silver salt dispersion. A method for producing an organic silver salt dispersion in a reaction vessel by adding a water-soluble silver salt to an alkaline salt aqueous solution or suspension of a long chain (10 to 30 carbon atoms ) aliphatic carboxylic acid, In the reaction tank, stirring along the inner wall or bottom and stirring with at least one high-speed stirring member that rotates at high speed are simultaneously performed, and 0. 0 per mole of organic acid is passed through a nozzle installed in the vicinity of the high-speed stirring member. A method for producing an organic silver salt dispersion, wherein silver nitrate corresponding to 9 to 0.97 mol is added.   A photothermographic material having a photosensitive layer containing a photosensitive silver halide, an organic silver salt, a reducing agent and a binder and a protective layer on a support, wherein the organic silver salt dispersion is defined in claim 1 or 3. A photothermographic material formed by the method described above.   5. An image forming method, wherein the exposure is performed by an exposure apparatus in which an angle formed between the exposure surface of the photothermographic material according to claim 4 and the scanning laser beam is not substantially perpendicular. An image forming method, wherein the photothermographic material according to claim 4 is heat-developed in a state containing 5 to 1000 mg / m ^{2 of a} solvent.   5. An image forming method comprising developing the photosensitive material protective layer according to claim 4 in contact with a heated drum.

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