Liquid development of electrostatic images

Claim 1

In an apparatus for developing electrostatic images on a charge retentive surface: development electrode means having a rough cylindrical surface comprising a plurality of discrete projecting surface portions, separated from one another by a plurality of recessive surface portions; means for mounting said development electrodE means for rotation about its axis of revolution; means for passing the charge retentive surface of a recording medium, for bearing latent charge images thereon to be developed, adjacent said rough surface of said development electrode and contiguous with said projecting surface portions thereof; means for rotating said development electrode means with an angular velocity such that said rough surface of said development electrode moves at a different speed than that of the adjacent charge retentive surface to be developed; and means for supplying liquid electrographic development toner, having electroscopic toner particles suspended in a dielectric liquid, to the rough surface of said development electrode so that the toner liquid is carried into contact with the charge images on the charge retentive surface to be developed for developing same, said liquid toner being carried within said recessive surface portions, said projecting surface portions serving to wipe liquid toner from said charge retentive surface, whereby said charge-retentive surface undergoes a plurality of successive development operations, each of said operations being followed by a wiping operation.