Method and apparatus for correction of focusing artifacts in ionographic devices

Abstract

Abstract An ionographic printing system including an imaging member with a charge retentive surface on which a latent image may be formed; a printhead including a source of ions, means for moving ions from the source to the charge retentive surface in a continuous stream, and means for modulating the stream in accordance with a desired image; and in which a projection field between the charge retentive surface and the printhead tends to focus ions in a manner reducing spread in directions parallel and anti-parallel to the process direction, there is provided means for defocusing and slightly repositioning the ion stream including an additional pair of electrodes arranged adjacent to the ion stream and an A.C. voltage source with time dependent bias, to apply an A.C. field across the ion stream at a frequency selected to sweep the ion stream in two directions parallel and anti-parallel to the process direction of the device. In doing so, ions are dispersed or spread over a wider area of the charge retentive surface than would otherwise be the case, and the beam is simultaneously repositioned as necessary to correct for mechanical errors in the instantaneous position of the charge retentive surface.

Inventors

• 👤 Frank C. Genovese

Bibliographic Details