To provide an ink composition giving excellent print quality on various recording media, especially high color development on plain paper, developing excellent gloss on glossy paper and having excellent ejection stability, preservation stability and clog recovering property.
The ink composition at least contains a solid solution pigment, a water-insoluble vinyl polymer containing the pigment and making the pigment to be dispersible in the ink composition, a compound expressed by formula (I) and water. The water-insoluble vinyl polymer is produced by the copolymerization of a monomer composition at least containing (A) a styrene macromer and (B) a monomer having a salt-forming group. In the formula, R is a 7-14C alkyl group; PO is propyleneoxy group; EO is ethyleneoxy group; m is an integer of 1-10; n is an integer of 5-20; and X is an integer of 1-3.
Yukitaka Nakamura
Konno Akio
Noritaka Yokota
Mari Asano