Hybrid development scheme for trilevel xerography

摘要

A hybrid development system for developing composite tri-level xerographic latent images in which conductive magnetic brush (CMB) development system is employed at the first development station and insulative magnetic brush (IMB) development system is used at the second station. In order to preclude spurious fringe field development by the IMB development system at the second development station the conductivity of the IMB developer is in the order of 10-13 to 10-15 ohm-cm. Additionally, a scorotron corona charging device located between the two development housings may be used to charge the image developed at the first station to the same potential as the background (white level) thereby eliminating spurious fringe field development by the IMB developer with a conductivity less than 10-13 ohm-cm at the second development station.