Patent ID: 7977409

Claim:
An ink jet ink comprising: a pigment; and a star polymer in which at least three copolymer chains of α,β-ethylenically unsaturated monomers are bonded to a central skeleton, wherein the copolymer chains of the α,β-ethylenically unsaturated monomers are copolymers of at least one first monomer selected from the group consisting of aromatic (meth)acrylates and aromatic (meth)acrylamides and at least one second monomer selected from the group consisting of acid monomers and salts of the acid monomers, and wherein an existence ratio [M 1 (50)/M 2 (50)]/[M 1 (100)/M 2 (100)] determined from an existence ratio M 1 (50)/M 2 (50) between the first monomer and the second monomer in a region from a start of a peak of a molecular weight distribution of the polymer obtained by gel permeation chromatography (GPC) in terms of polystyrene to 50% of the peak and an existence ratio M 1 (100)/M 2 (100) between the first and second monomers in a region from 50% to 100% of the peak is 0.8 or more and 1.2 or less.