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 that achieves both ejection stability from a head nozzle and high image density even after storing a recording apparatus used for printing, and storage stability.SOLUTION: An inkjet ink that contains pigment, water, water-soluble organic solvent, and a copolymer having a monomer (A) represented by the following general formula (1) as an essential component, and is characterized in that the increase ratio of viscosity relative to the initial viscosity when the pH dropped to 8.5 is 50% or more. The general formula (1): in the above formula, R1 denotes a hydrogen atom or a methyl group; R2 denotes an alkylene group having 4 to 22 carbon atoms; X1 denotes a NH group or an oxygen atom; and M1 denotes a hydrogen atom, an inorganic or organic cation of monovalent.