Patent ID: 8526835

Claim:
A method of operating a document processing system having a plurality of marking devices of different colors individually operable to transfer marking material in a first transfer operation onto an intermediate transfer structure, the method comprising: a) importing a plurality of control patches of preselected colors wherein the colors are repetitively imported in control patches at a plurality of electrostatic transfer bias set points; b) sensing a density of the control patches with a sensor; c) detecting a highest density color of the repetitively imported patches; and d) determining an optimal first transfer bias based on the detected highest density, whereby subsequent operation of the document printing system selectively employs the optimal first transfer bias; wherein the determining comprises computing the optimal first transfer bias (OFTB) by a function: Optimal First Transfer Bias=(0.5*( R+G )−0.5*( M+Y ))* X+ 0.5*( M+Y ) where R=transfer bias when red patch's density is the highest G=transfer bias when green patch's density is the highest M=transfer bias when magenta patch's density is the hiqhest Y=transfer bias when yellow patch's density is the highest and X=weight from 0 to 1, where 0 means single separation is more desired and 1 means blended color is more desired.