WATER BASE INK, METHOD OF INK JET RECORDING, INK CARTRIDGE, RECORDING UNIT, NK JET RECORDING APPARATUS AND METHOD OF IMAGE FORMATION

摘要

A water-based ink of the present invention includes water, a plurality of different water-soluble organic solvents, and a water-insoluble coloring material, wherein the above water-soluble organic solvents consist of a good solvent to the above water-insoluble coloring material and a poor solvent to the above water-insoluble coloring material, and the total amount (% by mass) of the good solvents in the ink is represented by A and the total amount (% by mass) of the poor solvent in the ink is represented by B, the ratio of A to B ranges from 10:5 to 10:30 both inclusive, and when the respective Ka values of the above water-soluble organic solvents are determined by the Bristow method and compared with each other, a water-soluble organic solvent having the largest Ka value is the poor solvent. The pigment ink has a sufficiently large area factor even with a small amount of ink and provides an image of high OD.