| abstract |
Disclosed herein is a water-based pigment inkncomprising a coloring material composed of self-dispersingncarbon black obtained by bonding at least one hydrophilicngroup directly or through an another atomic group to thensurface of carbon black, a humectant of the generalnformulan H-(CH 2 ) m -C-((CH 2 ) n OH) 3 nwherein m and n are independently an integer of from 1 ton5, and an aqueous medium composed of water and a water-solublenorganic solvent. |