Patent ID: 7431760

Claim:
An ink containing an azo dye having, in total, at least 13 conjugated π electrons in an aromatic ring thereof that is not directly bonded to any azo group, wherein the azo dye is represented by the following formula (8): wherein A represents a substituted or unsubstituted aromatic ring or a substituted or unsubstituted heterocyclic ring; R 3 and R 4 each represent a hydrogen atom, an aliphatic group, an aromatic group, a heterocyclic group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, an alkylsulfonyl group, an arylsulfonyl group or a sulfamoyl group, each of which may have a substituent, provided that R 3 ═R 4 ≠H; R 14 and R 15 each represent a hydrogen atom, an aliphatic group, an aromatic group, a heterocyclic group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, an alkylsulfonyl group, an arylsulfonyl group or a sulfamoyl group; and R 16 represents a substituted phenyl group, an unsubstituted naphthyl group or a substituted heterocyclic group.