Patent ID: 8222326

Claim:
A water-based ink composition for inkjet recording, comprising vinyl polymer particles and a water-based liquid medium, the vinyl polymer particles including: a styrene-(meth)acrylic acid copolymer including a constitutional unit derived from a styrene monomer and a constitutional unit derived from at least either acrylic acid or methacrylic acid, in which the total content of the constitutional units derived from the styrene monomer, acrylic acid, and methacrylic acid is 45% by mass or more with respect to a total amount of all monomers constituting the styrene-(meth)acrylic acid copolymer; and at least one of an azo pigment represented by the following Formula (1), a tautomer thereof, a salt of the azo pigment or tautomer, or a hydrate of the azo pigment or tautomer: wherein, in Formula (1), Q represents a 5- to 7-membered heterocycle together with two carbon atoms to which Q is bonded; W represents an alkoxy group, an amino group, an alkyl group, or an aryl group; X 1 and X 2 each independently represent a hydrogen atom, an alkyl group, an acyl group, an alkylsulfonyl group, or an arylsulfonyl group; R 1 represents a hydrogen atom or a substituent; R 2 represents a heterocyclic group; and n represents an integer of 1 to 4, provided that in the case of n=2 to 4, Formula (1) represents a dimer, a trimer, or a tetramer which is bonded via Q, W, X 1 , X 2 , R 1 , or R 2 .