Patent ID: 7378458

Claim:
A method for preparing an ink having constituents of a water-soluble dye having a water-soluble solubilizing group of at least one selected from the group consisting of a sulfonic group and a carboxyl group, water, a water-soluble substance that is condensation-polymerized in the absence of said water, a water-soluble medium and an additive including at least one selected from the group consisting of an organic acid salt and an inorganic acid salt, comprising: a first mixing step of mixing at least said dye and said water-soluble substance that is condensation-polymerized in the absence of said water out of said constituents of said ink excluding said additive; a pH adjusting step of preparing a solution including a mixture obtained in the first mixing step while adjusting said solution to a given pH range by using a pH adjuster; and a second mixing step, performed after the pH adjusting step, of mixing said solution including said mixture and said additive, wherein a cation of said additive is NH 4 + , and wherein the given pH range of said solution adjusted in the pH adjusting step is a pH range of 8 to 11.