Patent ID: 9321929
Filing Date: 2016-04-26
CPC Classification: C09D

Claim Text:
1. An ink composition comprising at least a magenta solid solution pigment, dispersant polymer, which can render the pigment dispersible in the ink composition, acetylene compound, vinyl polymer particles, and water, the ink composition exhibiting a UV visible absorption spectrum, wherein at least one absorption peak is present at a wavelength of 510 nm to 535 nm and at least one absorption peak is present at a wavelength of 550 nm to 570 nm, and the maximum value A of the absorbance in the wavelength range of 510 to 535 nm and the maximum value B of the absorbance in the wavelength range of 550 nm to 570 nm satisfies a relationship of 0.95≦A/B<1.0 wherein the dispersant polymer is produced by copolymerizing a monomer composition comprising at least a styrene macromer (A) and a salt forming group-containing monomer (B), and wherein the magenta solid solution pigment is a solid solution pigment comprising unsubstituted quinacridone and other quinacridone selected from the group consisting of 3,10-dichloroquinacridone, 2,9-dimethylquinacridone, and 2,9-dichloroquinacridone, wherein the vinyl polymer particles produced by copolymerizing a monomer composition comprising a polyoxyalkylene group-containing monomer (1), a salt forming group-containing monomer (2), and a monomer (3) copolymerizable with the polyoxyalkylene group-containing monomer and the salt forming group-containing monomer, wherein an average particle diameter of the vinyl polymer particles is 10 to 200 nm, wherein the polyoxyalkylene group-containing monomer polymerized by using monomer represented by the following formula: wherein R wherein the amount of the vinyl polymer particles added to the ink composition is 0.1 to 3.0% by weight.