Xerox Corporation

Thomas G Davis

George J Safford

Dror Sarid

A corona charging device comprising an elongated wire electrode and a shield partially surrounding the electrode, the shield being formed of a plurality of conducting segments insulated from each other and biased to a plurality of different potentials relative to the wire. The distribution of charge from the corona device onto an adjacent surface may be controlled by changing the biasing arrangement on the shield segments.

Corona device with segmented shield

A corona charging device having a corona electrode in the form of a conductive wire covered with a thick dielectric coating. The electrode is supported along its entire active length at a spaced distance from both an adjacent conductive plate and an imaging surface to be charged.

Corona device

A biasing arrangement for a corona discharge device including a conductive shield partially surrounding a corona electrode comprising means for applying a first high D.C. potential to the wire and a second high D.C. potential to the shield, the potential difference between the wire and the shield being sufficiently small to substantially inhibit corona current. A high voltage pulse train is superimposed on the shield which periodically increases the potential difference between the wire and the shield to foster ion generation adjacent the wire. Between pulses, the shield is returned to the second potential to again inhibit further ion generation while concurrently permitting ion movement toward a surface to be charged rather than toward the shield itself. Pulse duration and repetition rate are selected to enhance the efficiency of the corona device.

Biasing arrangement for a corona discharge device

A corona discharge device including a corona discharge electrode and a conductive shield located adjacent the electrode, the electrode being coated with relatively thick dielectric material so as to substantially prevent the flow of conduction current therethrough. The delivery of charge to the photoconductive surface is accomplished by means of a displacement current or capacitative coupling through the dielectric material. The flow of charge to the surface to be charged is regulated by means of a d.c. bias applied to the corona shield.

Corona charging device

A corona discharge arrangement for shifting the transfer point in a xerographic machine comprising an elongated wire and a shield having a plurality of conductive segments insulated from each other. A biasing arrangement is provided for changing the bias potentials on the various segments to effect a shift in the transfer point in response to preselected conditions. The transfer point may alternatively be maintained stationary by changes in the biasing potentials in response to changes in conditions which would otherwise result in a change in the transfer point.

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Pittsford, NY, United States of America

Thomas G Davis