Electrographic process control

An electrographic device that uses a chargeable image transfer member with at least one image area and has means for adjusting at least one process parameter in response to changes in the sensitometric characteristics of the image transfer member as measured in a portion of the image transfer means outside of the image area is disclosed. The device is provided with transfer member discharging means for subjecting the portion of the transfer member to a history of being charged and discharged substantially the same as the history of the image area of the transfer member. Preferably, the image transfer member is a photoconductor and the discharging means includes a light source and means for modulating said light source to statistically imitate a predetermined mix of original document types in response to at jobstream estimates, key operator input, and user selection.