Ink, and ink-jet recording method and instrument using the same

摘要

Disclosed herein is an ink comprising a dye having at least one anionic group, an amino acid type polyamine or a polyethyleneimine containing at least 7 nitrogen atoms in its molecule, and water, wherein the dye is either a metallized azo dye or a nonmetallized azo dye satisfying the following conditions (x) and (y) at the same time: (x) no anionic group is situated at an ortho position to the azo bond, and at least one anionic group exists at another position than the ortho position to the azo bond; and (y) at least one aromatic residue is bonded to the azo bond, and the aromatic ring of the aromatic residue is a benzene or naphthalene ring, with the proviso that the aromatic rings situated on both sides of the azo bond are not naphthalene rings at the same time if present.