Patent ID: 7926929
Filing Date: 2011-04-19
Classification: C09D

Abstract:
1. A printing system comprising: a substrate; a first colored ink comprising particles of a first pigment, said particles comprising a first net zeta potential; a second colored ink comprising particles of a second pigment; electrostatic dispersant particles having a net surface charge; said electrostatic dispersant particles being adhered to surfaces of said particles of said first pigment and said particles of said second pigment such that said particles of said first pigment and said particles of second pigment have a net zeta potential of the same polarity; and a polarity-reversing amount of a surfactant, such that said particles of said second pigment comprise a second net zeta potential opposite in polarity to said first net zeta potential; wherein said first and second colored inks are configured to be printed together over a common surface of said substrate to form a composite color.