Pigment dispersion, inkjet ink using the pigment dispersion, method for preparing the pigment dispersion and image forming method using the inkjet ink

摘要

A method for preparing a pigment dispersion including subjecting a mixture including at least a pigment, a dispersant and water to a first dispersion treatment using a media mill to prepare a first dispersion; and then subjecting the first dispersion to a second dispersion treatment using a media-less mill to prepare the pigment dispersion, wherein the pigment in the pigment dispersion has an average particle diameter (D50) of from 20 to 130 nm for pigments except carbon black or from 70 to 180 for carbon black, and the standard deviation of the particle diameter of the pigment is less than the average particle diameter (D50) for pigments except carbon black or one half of the average particle diameter (D50) for carbon black. A pigment dispersion prepared by the method. An inkjet ink including the pigment dispersion and one member selected from water, water soluble organic solvents, and surfactants.