Xerox Corporation

Christopher M Pattison

Deepak R Maniar

Thomas C Dombroski

Victor Berko-Boateng

Angela Schnuerch

Richard P N Veregin

Vladislav Skorokhod

Michael D Thompson

Paul Windsor Morehouse, Jr

Bernard A Kelly

Jackie B Parker

Mary L Mc Stravick

Rachael L Mc Grath

Shigang S Qui

Maria N V Mc Dougall

Mary B Schlitzer

Coated carrier particles are provided for use in developer compositions for electrophotographic imaging. The coated carrier particles include a carrier core and a resin coating that includes first and second polymer components. The coated carrier particles exhibit stable triboelectric charging during aging, decreased coating hardness, higher coating coverage, and an improved resilience to toner impaction.

Carrier compositions

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.

Carrier composition

Carrier comprised of a core, a polymer coating, and wherein said coating contains a mixture of an alkali metal lauryl sulfate and a conductive component.

Coated carriers

A developer includes black toner particles and carrier particles, the black toner particles including at least one binder, at least one black colorant and one or more external additives, wherein the toner particles comprise from about 7 to about 15 pph of the developer, and wherein the toner particles exhibit a triboelectric charge of from about &#x2212;25 to about &#x2212;50 &#x3bc;C/g at toner particle concentrations of about 7 to about 15 pph of the developer. The developer is ideally suited for use in a high speed (greater than 100 prints per minute) semiconductive magnetic brush development apparatus. Preferably, the black toner particles include a styrene acrylate binder, and the external additives include from about 1.3 to about 2.1% by weight of the toner particles of a first silica having an average particle size of from about 35 to about 45 nm, from about 0.5 to about 1.0% by weight of the toner particles of a second silica having an average particle size of from about 135 to about 160 nm, and from about 0.2 to about 0.5% by weight of the toner particles of a titania having an average particle size of from about 35 to about 45 nm, with an external additive toner surface area coverage of from about 25 to about 45%.

Black toner and developer

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Rochester, NY, United States of America

Christopher M Pattison