Liquid electrophoretic developer composition.

摘要

A liquid electrophoretic developer composition for developing electrostatic latent images, wherein pigment particles for obtaining improved dispersion stability in association with at least two polymers are dispersed in an electrically insulating non-polar carrier liquid having a volume resistivity of at least 10⁹ ohm.cm and a dielectric constant less than 3, characterised in that the composition comprises at least one polymer (hereafter called "polymer A") which forms a coating on the pigment particles and has a poor solubility in said liquid as determined by Test A herein described, and at least one polymer (hereafter called "polymer B") being chemically linked to the pre-coated polymer A, said polymer B having a good solubility in said liquid as determined by Test B herein described.