Electrophotographic liquid toner development apparatus

Claim 1

Apparatus for developing a charge image on the surface of a flexible recording medium through the use of a dielectric development fluid comprising, in cooperative combination: a. a perforated development electrode having an upwardly-facing surface, b. means for positioning a charge image bearing surface of a recording medium above and facing downwardly so as to be in physical contact with said upwardly-facing surface of said development electrode such that the portion of said recording medium in physical contact with said development electrode conforms directly to the configuration of the portion of said development electrode with which it is in contact, said means for positioning being free of the surface of said recording medium opposite said charge image bearing surface thereof over the portion of said recording medium adjacent said development electrode so that in absence of said recording medium, said means will not become wet by flow of said dielectric development fluid whereby said opposite surface of said recording medium will always remain dry, even if continuity thereof is interrupted, c. means for continuously causing said dielectric development fluid to flow upwardly through the perforations in said development electrode and against said charge image bearing surface of said recording medium, when present, so as to tend to form a fluid boundary layer on said recording medium, said development electrode, said recording medium, and said means for positioning all positioned to be free of said fluid in absence of said dielectric development fluid flow, and d. means for causing relative motion between said development electrode and said recording medium so as to cause the surface of said development electrode to remove continuously and substantially and replenish said boundary layer of said dielectric development fluid from between said development electrode and said recording medium.