Patent ID: 8328927

Claim:
A water-based ink for ink jet recording, comprising: a coloring agent; water; and a water-soluble organic solvent, wherein the coloring agent comprises a phosphate group-modified self-dispersing pigment, and the water-based ink further comprises a calcium ion and at least one selected from the group consisting of boric acid or a salt thereof, diglycolic acid or a derivative thereof, and a chelating agent; wherein at least one of the following Conditions 1 to 3 is satisfied: Condition 1 0.05 wt % to 3 wt % of boric acid or a salt thereof is contained in the total amount of the water-based ink, and the amount of the calcium ion with respect to the total amount of the water-based ink is in the range of 5 ppm to 300 ppm; Condition 2 0.05 wt % to 5 wt % of diglycolic acid or a derivative thereof is contained in the total amount of the water-based ink, and the amount of the calcium ion with respect to the total amount of the water-based ink is in the range from 5 ppm to 300 ppm; Condition 3 0.05 wt % to 5 wt % of the chelating agent is contained in the total amount of the water-based ink, and the amount of the calcium ion with respect to the total amount of the water-based ink is in the range from 5 ppm to 500 ppm.