To provide an ink composition which has excellent print qualities in various recording media, especially has excellent glossiness and fixability for glossy paper and has excellent ink reliability such as discharging stability, storage stability and clogging recovery.
This ink composition containing at least a surface-treated pigment capable of being dispersed and/or dissolved in an aqueous medium in a dispersant-free state, a water-insoluble vinyl polymer and water, wherein the surface-treated pigment is a pigment prepared by binding hydrophilic dispersing groups to the surface of a solid solution pigment comprising two or more pigments, and the water-insoluble vinyl polymer is a vinyl polymer prepared by polymerizing a monomer composition composed of (1) a polyoxyalkylene group-containing monomer, (2) a salt-producing group-containing monomer, and (3) a monomer capable of being copolymerized with the polyoxyalkylene group-containing monomer and the salt-producing group-containing monomer.
Yukitaka Nakamura
Konno Akio
Noritaka Yokota
Mari Asano