Patent ID: 7462228

Claim:
A water-based black ink composition comprising a water-soluble dye for black color (A) with ozone fastness and a condensed compound (B) of 4,4′-dinitrostilbene-2,2′-disulfonic acid or a salt thereof with aminobenzenes, or a reduced product (C) thereof, wherein the water-soluble dye for black color (A) is a dye for black color comprising at least one selected from the group consisting of an azo compound represented by the general Formula (3) as shown below: wherein, each of A and B independently represents a phenyl group or a naphthyl group which may be substituted, and each component of A and B contains at least one sulfo group; each of “a” and “b” represents a single bond, and a bonded position of the “a” bond is at the 2-position or 3-position, and a bonded position of the “b” bond is at the 6-position or 7-position; one of X and Y represents a hydroxyl group and the other an amino group; and “1” represents 1 or 2; each of m and n independently represents 0 or 1; and a counter ion of a sulfo group or a carboxyl group contained in a molecule is a hydrogen ion, an alkaline metal ion, a cation of an organic amine, or an ammonium ion, and an azo compound represented by the general Formula (4) as shown below: wherein, R 6 to R 11 represent substituents, and each of “c” and “d” represents a single bond, and a bonded position of the “c” bond is at the 10-position or 11-position, and a bonded position of the “d” bond is at the 14-position or 15-position; and “o” and “p” are 0 or 1; “q” is 1 or 2; and a counter ion of a sulfo group or a carboxyl group contained in a molecule is a hydrogen ion, an alkaline metal ion, a cation of an organic amine, or an ammonium ion.