Aqueous pigment ink composition

摘要

Disclosed is an aqueous pigment ink composition comprising at least water and carbon black, wherein a surface oxygen content of said carbon black is not less than 0.07 in atom-numeral ratio based on carbon atom measured by an X-ray photoelectron spectroscopic method, and a combined value of a surface carboxyl group carbon content and a surface hydroxyl group carbon content of said carbon black, the both being measured by an X-ray photoelectron spectroscopic method, is not less than 0.5%. The aqueous pigment ink composition realizes smooth printing with an ink jet nozzle, and smooth writing with a fine pen tip and it has sufficient density. Further, the recorded traces obtained by using the ink composition is excellent in water resistance.