Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Silver compound sensitizer containing
Reexamination Certificate
2000-01-28
2001-05-22
Chea, Thorl (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Silver compound sensitizer containing
C430S620000
Reexamination Certificate
active
06235462
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to thermally developable photosensitive material forming images through thermal development, and in particular to thermally developable photosensitive materials having a image forming layer coated by using an aqueous coating solution and exhibiting reduced fogging even when allowed to stand under a high humid atmosphere.
BACKGROUND OF THE INVENTION
Recently, in the field of printing plate making and medical treatments, effluents produced in wet process of image forming materials produce problems in working property, and reduction of the effluents is strongly desired in terms of environment protection and saving space. In response thereto, techniques of photothermal materials capable of forming sharp and clear black images on thermal development are needed. Such a technique is described in D. Morgan, “Dry Silver Photographic Materials” in Handbook of Imaging Materials, published by Marcel Dekker Inc. (1991) at page 48. The photographic materials described therein are developed at a temperature of 80° C. or higher and called a thermally developable photosensitive material.
However, it has been known that such a type of thermally developable photosensitive materials easily produce marked fog when allowed to stand in an atmosphere at a high humidity for a long period of time, leading to unfavorable results. In almost of the thermally developable photosensitive materials, a coating solution using organic solvents such as toluene, methyl ethyl ketone or methanol is coated to form a image forming layer. This is because polyvinyl acetal such as polyvinyl butyral used as a binder is soluble only in organic solvents. However, the use of an organic solvent is disadvantageous in terms of bad influences on human body in the manufacturing process and costs for recovering the solvent.
JP-A 49-562626, 50-151138, 53-116144, 58-28737 and 60-61747 (hereinafter, the term, JP-A means an unexamined, published Japanese Patent Application) describe a technique for forming the image forming layer by using a coating solution containing an aqueous solvent, in which aqueous soluble binders such as gelatin, polyvinyl alcohol and polyvinyl acetal are employed. Further, JP-A 10-73899 and 10-73901 describes a image forming layer containing a binder such as an aqueous-dispersible acryl type polymer or aqueous dispersible-dispersible polyvinyl acetal. The use of such a binder enables to form the image forming layer by using an aqueous solvent type coating solution, leading to merits in environment and cost. However, in cases where the image forming layer is formed using an aqueous coating solution, problems of fogging caused upon storage over a long period of time in atmosphere at high humidity become prominent. Further, it is desired to make the image forming layer thinner.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide thermally developable photosensitive materials of which image forming layer can be formed by coating an aqueous coating solution having advantages in environment protection and cost, and which exhibit a low fogging level even upon storage at a high humidity.
Another object of the invention is to provide a thermally developable photosensitive material exhibiting superior performance even when the image forming layer is made thinner.
The object of the present invention can be accomplished by the following constitution:
(1) A thermally developable photosensitive material comprising a support, an image forming layer containing an organic silver salt and optionally provided on the side of the image forming layer, a component layer, wherein at least one of the image forming layer and the component contains photosensitive silver halide grains; and after 10,000 mm
2
of the thermally developable photosensitive material is immersed in 100 ml of a liquid dispersing medium maintained at a temperature of 40° C. for a period of 60 min., the immersed photosensitive material is removed therefrom and the remaining liquid dispersing medium exhibits a silver potential of not more than 200 mV at 40° C., in which at least 30% by weight of the liquid dispersing medium is accounted for water;
(2) The thermally developable photosensitive material described in (1), wherein at least one of the image forming layer and the component layer contains a reducing agent or a precursor thereof;
(3) The thermally developable photosensitive material described in (1), wherein the image forming layer is formed by coating a coating solution for the image forming layer; at least 30% by weight of a liquid dispersing medium contained in the coating solution being water and the coating solution exhibiting a silver potential of not more than 200 mV;
(4) The thermally developable photosensitive material described in (1), wherein the image forming layer is formed by coating a coating solution of the image forming layer and drying it, at least 30% by weight of a liquid medium of the coating solution of the image forming layer being accounted for an organic solvent
(5) The thermally developable photosensitive material described in (1), wherein the organic silver salt is a silver salt of a polymer represented by the following formula (0):
—(X)x—(Y)y— Formula (0)
wherein X is a repeating unit derived from a monomer containing an acid group; Y is a repeating unit derived from a monomer except for X; x and y represent contents of X and Y, respectively, x is 5 to 95% by weight and y is 5 to 95% by weight, provided that the sum of x and y is 100%;
(6) The thermally developable photosensitive material described in (5), wherein in the silver salt of the polymer, at least 95% of the acid group of the polymer form a silver salt;
(7) The thermally developable photosensitive material described in (5), wherein the silver salt of the polymer is a silver salt of a polymer represented by the following formula
—(A)a—(B)b— Formula (1)
wherein A is a repeating unit derived from an ethylenically unsaturated monomer containing a carboxy group; B is a repeating unit derived from an ethylenically unsaturated monomer except for A; a and b represent contents of A and B, respectively, a is 5 to 95% by weight and b is 5 to 95%, provided that the sum of a and b is 100%;
(8) The thermally developable photosensitive material described in (5), wherein the image forming layer contains the silver salt of a polymer represented by the following formula (0) in an amount of not less than 50% by weight of the image forming layer and the image forming layer further containing a binder in an amount of less than 50% by weight of the image forming layer;
(9) The thermally developable photosensitive material described in (8), wherein the thickness of the image forming layer is 1 to 10 &mgr;m;
(10) The thermally developable photosensitive material described in (1), wherein the organic silver salt is a silver salt of a polymer obtained by polyaddition of a carboxy-containing dihydric compound and a diisocyanate compound;
(11) A method for preparing a thermally developable photosensitive material comprising a support, an image forming layer, and optionally provided on the side of the image forming layer, a component layer, in which at least one of the image forming layer and the component layer contains photosensitive silver halide grains, the method comprising: coating a coating solution to form an image forming layer wherein the coating solution comprises an organic silver salt and a liquid dispersing medium, at least 30% by weight of the liquid dispersing medium being water;
(12) A thermally developable photosensitive material comprising a support having one side thereof a photosensitive layer containing photosensitive silver halide grains, and further comprising an organic silver salt and a reducing agent capable of reducing the silver salt, wherein the photosensitive layer is formed by coating a coating solution, in which at least 30% by weight of a solvent is water and which exhibits a silver potential of not more than 200 mV;
(13) A thermally developable photosen
Bierman Jordan B.
Bierman, Muserlian and Lucas
Chea Thorl
Konica Corporation
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