COMPENSATING FOR PRINTING NON-UNIFORMITIES USING A TWO DIMENSIONAL MAP

Correction data is produced for density errors in prints produced using a printer. While printing a test image, the periods of rotation of one or more rotatable imaging members arranged along a receiver feed path in the printer are measured using respective period sensors. The printed test image is measured in both the cross-track and in-track directions and a two dimensional map of the one or more period sensors is determined. A reproduction error signal representing deviation from aim density is determined. The variations from the data at measured periods in one or both directions are used to produce a correction signal.