Aqueous ink, ink-jet recording method, recording unit, ink cartridge, ink set, and ink-jet recording apparatus

摘要

The present invention relates to aqueous ink that exhibits characteristics based on cationic self-dispersing carbon black, and that has superior ejection stability even after suspension of printing. The aqueous ink includes cationic self-dispersing pigment, in which at least one cationic group is bound to the surface of the pigment directly or with another atomic group therebetween, a water-soluble organic solvent, and water. In addition to this, the aqueous ink contains an acidic compound including a proton in the structure thereof that can be dissociated due to dissolution into water, and having a dissociation stage of the proton with a dissociation constant of less than 1.