Patent ID: 7878643

Claim:
An aqueous ink comprising at least an aqueous medium, a surfactant, and a dye, wherein the aqueous medium comprises only water and at least one water-soluble organic compound, a static surface tension of the aqueous medium is from 45 mN/m or more to 57 mN/m or less, and a dynamic surface tension of the aqueous ink satisfies the following conditions (1), (2), and (3): (1) the dynamic surface tension of the aqueous ink at a lifetime of 50 milliseconds is from 42 mN/m or more to less than 49 mN/m, (2) the dynamic surface tension of the aqueous ink at a lifetime of 500 milliseconds is from 28 mN/m or more to 38 mN/m or less, and (3) a difference between the dynamic surface tension of the aqueous ink at a lifetime of 50 milliseconds and the dynamic surface tension of the aqueous ink at a lifetime of 500 milliseconds is 7 mN/m or more.