Patent ID: 8905533

Claim:
An ink composition comprising: (a) a polymer comprising a repeating unit (a1) having a group represented by the following Formula (1′) and a repeating unit (a2) having a hydrophilic group; represented by the following Formula (2); (b) a radical polymerizable compound; (c) water; and (d) a colorant; wherein, in Formula(1′), each of R a and R b independently represents an alkyl group having from 1 to 4 carbon atoms; R a and R b may be bound to each other to form a 4- to 6-membered alicyclic structure; R c represents a hydrogen atom or a methyl group; Z represents a single bond, —COO—*, or —CONR d —*; R d represents a hydrogen atom or an alkyl group having from 1 to 4 carbon atoms; * represents a site bonding to X; and X represents a divalent organic group, and wherein, in Formula (2), R cy represents a hydrogen atom or a methyl group; Z y represents —COO—*, —CONR dy —*, or a single bond; R dy represents a hydrogen atom or an alkyl group having from 1 to 4 carbon atoms; R y represents a group selected from the group consisting of a single bond, an alkylene group, an arylene group, and an aralkylene group; A represents a hydrophilic group; and * represents a site bonding to R.