Hybrid scavengeless development using an apparatus and a method for preventing wire contamination

摘要

A developer unit for developing a latent image recorded on an image receiving member with marking particles, to form a developed image. A donor member is spaced from the image receiving member and adapted to transport marking particles to a development zone adjacent the image receiving member. An electrode is positioned in the development zone between the image receiving member and the donor member. A voltage supply is provided for electrically biasing the electrode during a developing operation with an alternating current bias to detach marking particles from the donor member, forming a cloud of marking particles in the development zone, and developing the latent image with marking particles from the cloud. The voltage supply periodically electrically biases the electrode during a cleaning operation with a direct current bias and with a alternating current bias so that toner is effectively removed from the wire. The bias levels are chosen to reduce field induced redeposition of right or wrong sign toner.