Browse Prior Art Database

Original Publication Date: 1976-Jun-30
Included in the Prior Art Database: 2004-Mar-27

Publishing Venue

Xerox Disclosure Journal


A photoconductor 14 is charged by a corona discharge electrode 16 with positive ions as it rotates in a clock~ wise direction therepast. The potential of the photoconduc~ tor depends on the photoconductive material, its thickness, etc., but will ordinarily be approximately +1000 volts. A dielectric web 18, transparent to light, is moved in the direction from a supply spool 20 to a take-~up spool 22 and brought into contact with the photoconductive surface 14 and is exposed to a light pattern representing an image on a document 31. Since the web 18 is transparent to the exposure light, the electric field in the photoconductor corresponding to the background areas, where light impinges the photoconductor, is collapsing and thus the potential at the photoconductive surface corresponding to such areas is being lowered. The potential at the dielectric surface is the result of the charge on that surface and the potential at the surface of the photoconductor below it, An equal potential corona discharge electrode 36 generates positive ions, and since the corona discharge electrode 36 tends to be an equipotential charging device, it will attempt to charge the dielectric until the potential at the surface is equal for all points that have passed beneath it. As the