Patent ID: 7396863

Claim:
An ink set comprising a black ink and a color ink, wherein the black ink consists essentially of an aqueous dispersion of anionic water-insoluble vinyl polymer particles containing (i) a vinyl polymer and (ii) carbon black, and wherein the water-insoluble anionic vinyl polymer particles have an ionicity opposite to that of the color ink, and said vinyl polymer comprises a water-insoluble vinyl polymer prepared by copolymerizing (a) a salt forming group-containing monomer, (b) a monomer represented by the formula (I): CH 2 ═C(R 1 )COO(R 2 O) p R 3 (I) wherein R 1 is hydrogen atom or a lower alkyl group, R 2 is a divalent hydrocarbon group which may have a hetero-atom, R 3 is a monovalent hydrocarbon group which may have a hetero-atom, and p is a number of 1 to 60, (c) a styrenic macromer having a polymerizable functional group at one end, and (d) a styrenic monomer copolymerizable with these monomers.