Patent ID: 6184914
Filing Date: 2001-02-06
Classification: B41J,G03G,H04N

Abstract:
An electrophotographic imaging system for producing gray level images, comprising:a charger for repetitively charging a photoconductor to a first charge potential;a laser system for selectively discharging said photoconductor in accordance with applied image signals, said laser system adapted to discharge said photoconductor to at least a first high charge voltage and a second low charge voltage;a first toner supply for providing a first toner to said photoconductor, said first toner supply including a development roller and means for dispersing said first toner onto said development roller in a sparse fashion such that said first toner, when developed onto said photoconductor exhibits a non-continuous toned surface, said first toner exhibiting an intrinsic charge state that is attracted to said photoconductor by said second low charge voltage;a second toner supply for providing a second toner to said photoconductor, said second toner exhibiting a higher intrinsic charge state and of a same sense as the intrinsic charge state of said first toner, said second toner attracted to said photoconductor by either said first high charge voltage or said second low charge voltage; andcontrol means for modulating said laser system in accordance with applied data (i) to cause said photoconductor to exhibit said first high charge voltage when both said first toner and second toner are to be developed and (ii) to cause said photoconductor to exhibit said second low charge voltage when only said first toner is to be developed.