Patent ID: 7648943

Claim:
An azo dye represented by formula (I): wherein A represents a residue of a 5-membered heterocyclic diazo component A-NH 2 ; B 1 and B 2 each represents ═CR 1 — or ═CR 2 —, or one of B 1 and B 2 represents a nitrogen atom and the other of B 1 and B 2 represents ═CR 1 — or ═CR 2 —; R 3 and R 4 each independently represents 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 the groups optionally has a substituent; R 1 and R 2 each independently represents a hydrogen atom, a halogen atom, an aliphatic group, an aromatic group, a heterocyclic group, a cyano group, a carboxyl group, a carbamoyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyl group, a hydroxyl group, an alkoxy group, an aryloxy group, a silyloxy group, an acyloxy group, a carbamoyloxy group, a heterocyclic oxy group, an alkoxycarbonyloxy group, an aryloxycarbonyloxy group, an alkylamino group, an arylamino group, a heterocyclic amino group, an acylamino group, an ureido group, a sulfamoylamino group, an alkoxycarbonylamino group, an aryloxycarbonylamino group, an alkylsulfonylamino group, an aryloxycarbonylamino group, a nitro group, an alkylthio group, an arylthio group, an alkylsulfonyl group, an arylsulfonyl group, an alkylsulfinyl group, an arylsulfinyl group, a sulfamoyl group, a sulfo group or a heterocyclic thio group, each of the groups optionally has a substituent, and R 1 and R 3 are optionally taken together, or R 3 and R 4 are optionally taken together, each to form a 5- or 6-membered ring; a and e each independently represents an alkyl group, and the alkyl groups represented by a and e have at least three carbon atoms in total that constitute the alkyl groups, and each of the groups optionally has a substituent; b, c, and d each independently has a same meaning as R 1 and R 2 , and a and b are optionally taken together, or e and d are optionally taken together, each to form a condensed ring; and formula (I) has at least one ionic hydrophilic group.