Photothermographic material and image forming method
A photothermographic material having an image forming layer provided on at least one side of support, the image forming layer comprising a photosensitive silver halide, a non-photosensitive organic silver salt, a reducing agent and a binder, wherein: 50% or more of grains of the photosensitive silver halide in a projected area have an aspect ratio of from 2 to 100; and the binder comprises an aqueous dispersion of a hydrophobic polymer, and an image forming method thereof.
1 . A photothermographic material having an image forming layer provided on at least one side of support, the image forming layer comprising a photosensitive silver halide, a non-photosensitive organic silver salt, a reducing agent and a binder, wherein:
50% or more of grains of the photosensitive silver halide in a projected area have an aspect ratio of from 2 to 100; and
the binder comprises an aqueous dispersion of a hydrophobic polymer.
2 . The photothermographic material according to claim 1 , wherein 50% or more of grains of the photosensitive silver halide in a project area have an aspect ratio of from 8 to 50.
3 . The photothermographic material according to claim 1 , wherein the non-photosensitive organic silver salt is a silver salt of a fatty acid.
4 . The photothermographic material according to claim 1 , wherein a glass transition temperature of the hydrophobic polymer is in the range of −20° C. to 60° C.
5 . The photothermographic material according to claim 1 , wherein an equilibrium moisture content of the hydrophobic polymer at 25° C. and 60% RH is in the range of 0.01% by mass to 1.5% by mass.
6 . The photothermographic material according to claim 1 , wherein the hydrophobic polymer is a polymer produced by copolymerizing a monomer represented by the follwing formula (M):
CH 2 ═CR 01 —CR 02 ═CH 2 Formula (M),
wherein R 01 and R 02 each independently represent a member selected from the group consisting of: a hydrogen atom, an alkyl group having from 1 to 6 carbon atoms, a halogen atom and a cyano group.
7 . The photothermographic material according to claim 1 , wherein the hydrophobic polymer comprises a styrene-butadiene copolymer.
8 . The photothermographic material according to claim 1 , wherein 50% or more of grains of the photosensitive silver halide in a projected area have a thickness of 0.3 μm or less.
9 . The photothermographic material according to claim 1 , wherein an average sphere-equivalent diameter of the photosensitive silver halide is in the range of 0.3 μm to 5 μm.
10 . The photothermographic material according to claim 1 , wherein an average sphere-equivalent diameter of the photosensitive silver halide is in the range of 0.4 μm to 3 μm.
11 . The photothermographic material according to claim 1 , wherein the photosensitive silver halide comprises silver iodide in the range of 40% by mol to 100% by mol.
12 . The photothermographic material as set forth in claim 1 , wherein the photosensitive silver halide comprises silver iodide in the range of 80% by mol to 100% by mol.
13 . The photothermographic material according to claim 1 , wherein the image forming layer is provided on both sides of the support.
14 . The photothermographic material according to claim 1 , wherein a coated amount of the binder in the image forming layer is in the range of 0.2 g/m 2 to 30 g/m 2 .
15 . An image forming method for a photothermographic material having an exposing and a thermal-developing, the method comprising
(1) obtaining an assembly for image forming by placing the photothermographic material according to claim 1 between a pair of X-ray sensitizing screens,
(2) setting a subject between the assembly for image forming and an X-ray source,
(3) irradiating the subject with X rays having an energy level in the range of 25 kVp to 125 kVp,
(4) removing the photothermographic material from the assembly; and
(5) heating the removed photothermographic material at a temperature in the range of 90° C. to 180° C.