Compensating densitometer readings for drifts and dusting

摘要

Densitometer readings are corrected by obtaining density readings on an untoned area of the interframe region of an image receiver during cycle-up, storing the readings and subtracting the stored readings from subsequent test readings of the same area of the image receiver. Differences between the cycle-up readings and test readings are used to adjust density readings of toned reference patches obtained with the test readings. The procedure can be used during production modes of the machine, with all readings being taken in the interframe regions, or the procedure can be a part of an automatic set-up operation with toned reference patch readings being taken in the image frame areas of the image receiver.