Patent ID: 6589703
Filing Date: 2003-07-08
Classification: G03G

Abstract:
A method for development of an electrostatic image comprising contacting the image with at least one magnetic brush comprising:(a) a rotating magnetic core of a pre-selected magnetic field strength; (b) an outer nonmagnetic shell disposed about the rotating magnetic core; and (c) an electrographic developer composition disposed on an outer surface of the shell and in contact with the image, the developer composition comprising a mixture of charged toner particles and oppositely charged carrier particles comprised of a hard magnetic material, the toner particles having dispersed on the outer surfaces thereof at least one surface-treatment agent selected from the group consisting of: beads of a polymer selected from acrylic polymers, styrenic polymers, silicone-based polymers, and fluoropolymers; hydrophobic silica that has been surface treated with silicone oil or hexamethyldisilazane; and mixtures thereof.