Patent ID: 7621630

Claim:
An ink set comprising a black ink composition and at least one chromatic color ink composition, wherein said black ink composition comprises a surface-treated pigment dispersible and/or dissolvable in water without any dispersant, two or more types of resin particles, and water as a main solvent, at least one type of resin particles among the two or more types of resin particles have a film forming temperature below 0° C., and at least one type of resin particles among the two or more types of resin particles have a film forming temperature of 30° C. or above, and said chromatic color ink composition comprises at least a pigment, a polymer, which includes said pigment and renders said pigment dispersible in the chromatic color ink composition, and water as a main solvent, wherein said polymer contains hydrophobic and hydrophilic groups and is substantially insoluble in the chromatic color ink composition, or said polymer is a vinyl polymer prepared by polymerizing A) 5 to 45% by weight of at least one monomer selected from monomer A1 represented by formula (I): wherein R 1 represents a hydrogen atom or a methyl group, R 2 represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and n is 1 to 30, monomer A2 represented by formula (II): wherein R 1 , R 2 , and n are as defined in formula (I), m is 1 to 30, and the oxyethylene groups and the oxypropylene groups within [ ] may be added to each other as blocks or randomly, and monomer A3 represented by formula (III): wherein R 1 , R 2 , and n are as defined in formula (I), B) 3 to 40% by weight of a monomer containing a salt forming group, C) 5 to 40% by weight of a macromonomer having a number average molecular weight of 500 to 500,000, and D) 0 to 87% by weight of a monomer copolymerizable with monomers A), B), and C).