Patent ID: 7427319

Claim:
An azo compound represented by the following formula (1): (wherein, in the formula (1), R 1 , represents a hydrogen atom; a hydroxyl group; a carboxyl group; a (C 1 -C 4 )alkyl group which may be substituted by a hydroxyl group or a (C 1 -C 4 )alkoxy group; a (C 1 -C 4 )alkoxy group which may be substituted by a hydroxyl group or a (C 1 -C 4 )alkoxy group; a (C 1 -C 4 )alkylamino group which may be substituted by a hydroxyl group or a (C 1 -C 4 )alkoxy group; a carboxy(C 1 -C 5 )alkylamino group; a bis{carboxy(C 1 -C 5 )alkyl}amino group; a (C 1 -C 4 )alkanoylamino group which may be substituted by a hydroxyl group or a (C 1 -C 4 )alkoxy group; a phenylamino group which may be substituted by a carboxyl group, a sulfonic acid group or an amino group; a sulfo group; a halogen atom; or a ureide group, and A represents an aliphatic amine residue having a carboxyl group or a sulfo group, respectively; or a salt thereof.