Disclosed is an ink composition for jet printer, comprising a pigment, a film forming resin and an organic solvent, the film forming resin being an acrylic copolymer containing, as a monomer unit, at least one of compounds represented by the general formulas (1) and (2): wherein R1 represents a hydrogen atom or a methyl group; R2 represents an alkylene group having 2 to 12 carbon atoms which may be linear or branched; and R3 and R4 each independently represents a hydrogen atom, an alkyl group, an alkenyl group or an aryl group, and the sum of the number of carbon atoms of R3 and R4 is from 4 to 12, or R3 and R4 form a saturated or unsaturated hydrocarbon group which is a five-membered ring formed by combination of the R3 and R4; and wherein R1 represents a hydrogen atom or a methyl group; R2 represents an alkylene group having 2 to 12 carbon atoms which may be linear or branched; and X represents a group selected from the group consisting of groups represented by the general formulas (3) to (9).