Patent ID: 6027870
Filing Date: 2000-02-22
Classification: C09B,G03C,Y10S

Abstract:
A photothermographic material having on at least one side of a support, a binder, an organic silver salt, a reducing agent for silver ions and light-sensitive silver halide grains, said photothermographic material containing a dye represented by the following formula (I) or (II): ##STR11## wherein R.sub.1 and R.sub.2 each represents a carboxyalkyl group having 2 to 5 carbon atoms including the carbon atom of the carboxy moiety, the carboxy moiety of which has the undissociated form of COOH or the ionic form of COO.sup.- ; two substituents selected from among R.sub.3, R.sub.4, R.sub.5, R.sub.6 and R.sub.7 so as to form a couple of R.sub.3 and R.sub.5, a couple of R.sub.4 and R.sub.6 or a couple of R.sub.5 and R.sub.7 represent groups for forming a 6-membered ring by combining with each other, and each of the substituents except those participating in the ring formation represents a hydrogen atom; Z.sub.1 and Z.sub.2 each represents an atomic group for completing a 5- or 6-membered nitrogen-containing heterocyclic ring; and X represents a counter ion for adjusting the charge balance; ##STR12## wherein Y.sub.1 represents an oxygen atom, a sulfur atom, a selenium atom, NR or CR'.dbd.CR""--, wherein R is a lower alkyl group and R' and R"" each represents a hydrogen atom or an alkyl group; Y.sub.2 represents an oxygen atom, NR or --CR'.dbd.CR""--, wherein R is a lower alkyl group, and R' and R"" each represents a hydrogen atom or an alkyl group; Z.sub.1 and Z.sub.2 each represents a nonmetal atomic group for completing a benzene or naphthalene ring; X represents a counter ion for adjusting the charge balance; i represents 0 or 1; R.sub.1 and R.sub.2 each represents a carboxyalkyl group, the carboxy moiety of which has the undissociated form of COOH or the ionic form of COO.sup.-.