INKJET INK, IMAGE FORMATION METHOD, INK CARTRIDGE, INKJET RECORDING APPARATUS, AND IMAGE FORMATION PRODUCT

摘要

PROBLEM TO BE SOLVED: To provide an inkjet ink achieving both high image density and storage stability, that can record with high image density on plain paper, that has a good ink storage stability, and that also has a good ejection stability from head nozzle even after storing the recording apparatus used for printing.SOLUTION: An inkjet ink that contains pigment, water, water-soluble organic solvent and a copolymer, and in which the copolymer is a copolymer having 12-methacrylamide dodecanoic acid [monomer (A)] as an essential component and having other aromatic monomer as copolymerization component, and in which the initial pH is 9 to 11 and the increase ratio of viscosity relative to the initial viscosity when the pH dropped to 8.5, is 30% or more.