Abstract: A control device for adjusting the surface potential of an image bearing member of a machine during the initial cycles of a job run wherein the image bearing member manifests varying characteristics after completion of a job run. The control device includes a charging member to produce a surface potential on the image bearing member, a sensor to measure the surface potential on the image bearing member and logic circuitry responsive to the charging member and the sensor after a first cycle of the machine operation to control the charging member current during a second cycle of the machine operation in which the logic circuitry includes means to predict changed characteristics of the image bearing member after the completion of the first job run at the initiation of a second job run and the means to determine relationship between the charging current of the charging member and the measured surface potential of the image bearing member.

Abstract: An apparatus in which a latent image is developed with particles having low conductivity. The particles are attracted to a member vibrating relative to the latent image. This increases the bulk conductivity of the particles being deposited on the latent image so as to improve development thereof.