Patent ID: 7699924

Claim:
An aqueous ink comprising: water; a water-soluble organic solvent; a water-insoluble coloring material; a surfactant; and a salt, wherein the surfactant is a polyoxyethylene alkyl ether, wherein the salt is formed of (a) a cation selected from the group consisting of a metal ion, an ammonium ion, and an organic ammonium ion and (b) an anion selected from the group consisting of Cl − , Br − , I − , ClO − , ClO 2 − , ClO 3 − , ClO 4 − , NO 2 − , NO 3 − , SO 4 2− , CO 3 2− , HCOO − , CH 3 COO − , C 2 H 4 (COO − ) 2 , C 6 H 5 COO − , and C 6 H 4 (COO − ) 2 , wherein a dynamic surface tension, at 25° C., of the aqueous ink at a lifetime of 50 milliseconds determined by a maximum bubble pressure method is higher than 47 mN/m, wherein a dynamic surface tension, at 25° C., at a lifetime of 5,000 milliseconds determined by the maximum bubble pressure method is 38 mN/m or lower, and wherein the content (mass %) of the surfactant is from 0.10 mass % or more to 0.75 mass % or less based on the total mass of the ink.