Patent ID: 7527685

Claim:
An ink for ink-jet recording comprising: an anionic self-dispersing coloring agent; a surfactant having both of a cationic moiety and a nonionic moiety; and water; wherein a curve, which represents a change of surface tension of the ink with respect to a concentration of the surfactant, has one inflection point, the curve has a first local maximum point and a second local maximum point on a low concentration side and on a high concentration side of the inflection point respectively, and a concentration of the surfactant contained in the ink is higher than a concentration corresponding to the first local maximum point, and wherein the surfactant is an alkylamine ethylene oxide adduct represented by the following general formula (1): wherein R 1 represents alkyl group having a number of carbon atoms of 8 to 18, and x and y represent integers which satisfy x+y=5 to 15.