| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an aqueous pigment dispersion excellent in dispersion stability and heat resistance and having a small arithmetic-average particle size, and to provide an ink composition achieving stable ink discharge over a long period not only in a piezo-system but also in a thermal system for which ink storage stability at high temperatures is required, and imparting a printed matter with high optical density and high gloss. <P>SOLUTION: The aqueous pigment dispersion comprises (A) an azo-based yellow pigment PY74, (B) a pigment derivative obtained by introducing a sulfonic acid group into an azo-based yellow pigment which has a higher molecular weight than the azo-based yellow pigment PY74, (C) water, and (D) a water-soluble organic solvent. <P>COPYRIGHT: (C)2008,JPO&INPIT |
