WATER-BASED PIGMENT DISPERSION, WATER-BASED INK AND IMAGE-FORMING METHOD USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a water-based ink excellent in chroma and transparency of a color image and further improved in water resistance from a conventional self-dispersible pigment. SOLUTION: The water-based ink is prepared using the water-based pigment dispersion comprising an aqueous medium and, dispersed therein, a self- dispersible organic pigment which is obtained by bonding, to an organic pigment having a primary particle size of 10-50 nm having a hydrophilic group incorporated thereinto in advance by a plasma treatment, a hydrophilic group other than the above hydrophilic group directly or via other atomic group.