US Patent 7419755 Carrier composition

Carrier particles comprise a core and a polymer coating that comprises a mixture of polymethyl methacrlyate (PMMA) and melamine. The coating compositions comprise from about 60 to about 80 percent by weight of PMMA and from about 20 to about 40 percent by weight of melamine. The carriers may be combined with a toner to provide a developer suitable for use in an electrostatographic process. Carriers comprising the PMMA/melamine coatings exhibit increased triboelectric charging, a more conductive carrier, and also contribute to reducing toner cohesion.