Electrical method and apparatus to control corona effluents

摘要

A corona generating assembly for charging a photoconductive surface includes a corona generator connected to a relatively large first voltage source to produce ions directed to the photoconductive surface. A conductive screen member or scorotron grid is operatively connected to a second voltage source to control the flow of ions generated from said corona generator to and through said conductive screen. The conductive screen and corona generator are arranged such that the conductive screen is between the corona generator and the photoconductive surface to be charged. A switching arrangement is provided for operatively connecting the conductive screen member with a third voltage source when the first and second voltage sources are removed from the corona generator and conductive screen. Through this arrangement an electrical potential is impressed on the conductive screen member to create a positive electrical field which inhibits effluent outgassing to the photoconductive surface, thus preventing the development of a significant copy quality defect.