Water-based ink

Abstract

The present invention relates to a water-based ink including a pigment, a water-insoluble polymer, an organic solvent and a surfactant, in which the organic solvent includes at least a glycol ether which has a viscosity of from 2.0 to 7.0 mPa·s and a vapor pressure from 0.01 to 7.0 hPa as measured at 20° C., and a content of a glycol ether having a viscosity of not less than 6.0 mPa·s as measured at 20° C. as a component of the glycol ether in the water-based ink is from 0 to 5% by mass; the surfactant includes a silicone-based surfactant and a content of the silicone-based surfactant in the water-based ink is from 0.005 to 0.3% by mass; a content of the organic solvent in the water-based ink is from 25 to 50% by mass; and a content of a high-boiling organic solvent in the water-based ink is not more than 5% by mass, an ink set for ink-jet printing including two or more kinds of water-based inks which are each constituted of the aforementioned water-based ink, and an ink-jet printing method including the steps of ejecting the aforementioned water-based ink onto a printing medium, and further ejecting the water-based ink onto the printing medium to overstrike the water-based ink onto the water-based ink that has been ejected onto the printing medium in the previous step. The water-based ink of the present invention is excellent in continuous ejection properties, and is capable of obtaining good printed materials that are free of roller transfer contamination and intercolor bleeding owing to overstriking of the inks even when printed on a non-water absorbing printing medium.