A carbon black aqueous dispersion which exhibits excellent dispersibility
in an aqueous medium, a small amount of feathering, excellent rubbing
resistance (quick-drying properties), excellent discharge stability, and
the like, and is suitable as an ink for inkjet printers and the like, and
a method of producing the same are disclosed. The carbon black aqueous
dispersion includes an aqueous medium and carbon black dispersed in the
aqueous medium, acidic hydrogen-containing groups on the surface of the
carbon black being neutralized with divalent or higher valent cations and
monovalent cations so that 50 to 95% of hydrogen atoms of the acidic
hydrogen-containing groups are replaced by the divalent cations and the
remaining hydrogen atoms are replaced by the monovalent cations, and the
method includes subjecting carbon black to liquid-phase oxidation in an
oxidizing agent aqueous solution, removing reduced salts from the
resulting slurry, adding divalent or higher valent cations and monovalent
cations to the slurry to replace 50 to 95% of hydrogen atoms of acidic
groups by the divalent cations and replace the remaining hydrogen atoms
by the monovalent cations, and purifying the resulting product.