A planar array of microcells is formed in a support. An electrostatic charge pattern is established on the support differentiating first and second interlaid sets of microcells. An electrographic imaging composition is introduced into the first set of microcells, and a second, differing imaging composition...http://www.google.de/patents/US4307165?utm_source=gb-gplus-sharePatent US4307165 - Plural imaging component microcellular arrays, processes for their fabrication, and electrographic compositions
