Patent ID: 8173226

Claim:
An ink composition comprising: a polymer; a polymerizable compound (a); and a pigment (b), wherein the polymer comprises a copolymer unit derived from a monomer represented by formula (1): wherein, in the formula (1), R 1 represents any one of a hydrogen atom, a substituted alkyl group, and an unsubstituted alkyl group; R 2 represents an alkylene group; W represents any one of —CO—, —C(═O)O—, —CONH—, —OC(═O)—, and an unsubstituted phenylene group; X represents any one of —CO—, —NHCO—, —OC(═O)—, —CH(OH)CH 2 —, and —SO 2 —; R 3 and R 4 each independently represents a monovalent substituent and the monovalent substituent is any one of a hydrogen atom, an alkyl group, an aryl group, a halogen atom, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an alkoxycarbonyl group, an acylamino group, a carbamoyl group, a cyano group, an alkylsulfonyl group, an arylsulfonyl group, an acyl group, a sulfamoyl group, an acyloxy group, a carboxyl group, and a sulfonyl group; R 3 and R 4 do not bind to each other to form a ring structure; and m and n each independently represent 0 or 1.