Patent ID: 6432627
Filing Date: 2002-08-13
Classification: G03C,Y10S

Abstract:
A photothermographic element comprising at least one photosensitive layer on a support, whereinsaid element contains a non-photosensitive silver salt of a long-chain aliphatic carboxylic acid having 10-30 carbon atoms, a reducing agent for silver ion, and an emulsion of photosensitive silver halide fine grains having a mean equivalent spherical diameter of 10 to 50 nm, said silver halide emulsion has been performed independent of the silver salt and subsequently mixed with the silver salt before coating, and the silver halide fine grains have been chemically sensitized in the presence of a spectral sensitizing dye, wherein the photothermographic element is prepared by the following sequential steps: (A) forming said photosensitive silver halide emulsion independent of the non-photosensitive aliphatic carboxylic acid silver salt, the emulsion containing silver halide fine grains having a mean equivalent spherical diameter of 10 to 50 nm, (B) adding a spectral sensitizing dye to the photosensitive silver halide emulsion, (C) chemically sensitizing the silver halide fine grains in the presence of said spectral sensitizing dye, (D) mixing the silver halide emulsion with the non-photosensitive aliphatic carboxylic acid silver salt, and (E) coating the resulting mixture onto the support.