| abstract |
An aqueous medium containing an aqueous medium and resin fine particles composed of a resin, wherein the resin has a structural unit represented by the general formula (1) or (2), and the content of the resin fine particles is 1 to 15% by mass. Ink composition, ink set and image forming method using the same, and resin fine particles suitable for the aqueous ink composition: R 1 , R 2 and R 3 represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. A 1 represents —O— or —NR 3 —. L 1 represents an alkylene group having 6 to 22 carbon atoms. M 1 and M 2 represent a hydrogen atom, an alkali metal ion or an ammonium ion. A 2 represents a single bond, —COO— or —CONH—. L 2 represents a divalent linking group having 6 to 23 carbon atoms. |