Abstract: Non-contact corona charging of a small radius moving surface to a desired surface voltage with a single corona charging system with a first corona generator applying a first charge through a screen grid having a first bias voltage to initially charge the surface to more than half of the desired voltage, and then a second corona generator applies the remainder of the desired surface charge through a separate screen grid having a second bias voltage. The two corona generators may be spaced pin arrays angled relative to one another and substantially perpendicular to their adjacent moving surface areas. The two screen grids may be electrically planar and angled relative to one another, substantially parallel to their adjacent moving surface areas.

Abstract: In a xerographic printing apparatus, a scorotron places a uniform charge on a photoreceptor for forming electrostatic latent images. Two conductive pin arrays are disposed in a housing defined by sidewalls and a grid adjacent the photoreceptor. For each array, the distance to the adjacent sidewall is 1.0 to 1.5 the distance to the grid.