| 摘要 |
PROBLEM TO BE SOLVED: To provide a water-base pigment dispersion having good storage stability with time, settling property and filtering property, and to provide a pigment-type ink-jet recording liquid using the pigment dispersion, having nozzle discharge stability, a sufficient color-reproducibility range upon printing, and properties of good water resistance and light stability compatible with each other. SOLUTION: A method for producing water-base pigment dispersion comprises the steps of sulfonating a pigment in a strong acid to precipitate a sulfonic acid group-containing pigment derivative which has not formed salt, washing the sulfonic acid group-containing pigment derivative with an organic solvent, and dispersing the pigment in water using the washed sulfonic acid group- containing pigment derivative. |
