Patent ID: 6014158
Filing Date: 2000-01-11
Classification: G03G

Abstract:
An electrostatographic reproduction apparatus having a transfer assembly, including an electrically biased transfer roller in nip relation with a dielectric support member, for effecting transfer of a pigmented marking particle image from an image area of said dielectric support member to a receiver member, having a lead edge and a trail edge, transported along a path in transfer relation with said dielectric support member in said transfer nip, a mechanism for cleaning said transfer roller including a control for the electrical bias on said transfer roller, said electrical bias control comprising:a power supply selectively generating an electrical output at constant current or constant voltage of a settable polarity, said power supply being connected to said transfer roller for applying an electrical bias of a set polarity to said transfer roller;a timing signal generator producing signals respectively corresponding to a receiver member in said path relative to said transfer nip, wherein said constant current electrical output occurs during transfer, and said constant voltage electrical output occurs between a signal indicating a trail edge of a receiver member and a signal indicating a lead edge of a next subsequent receiver member entering said transfer nip, and said power supply locks in, for later recall, the voltage for said constant current electrical output; andmeans, responsive to a signal from said timing signal generator indicating said trail edge of a receiver member through said transfer nip, for reversing the set polarity of said electrical output from said power supply so as to prevent transfer of residual marking particles from said dielectric support member to said transfer roller.