Abstract: The present disclosure describes a method of automatically controlling feeding and transporting print media sheets through plural electrostatic print engines having seamed photoreceptor belts for duplex printing. In one embodiment the second photoreceptor belt is driven at a variable speed to maintain a constant phase relationship between the respective seams of the belts. The print image magnification on the front side of the printed sheet is matched by varying the speed of the scanner (ROS) in the second engine. In another embodiment. the first and second photoreceptor belts are both driven at a constant speed and the seam phase allowed to float. Sensors provide a timing signal upon passage of the seam in each belt respectively; and, the position of the belt seams thus determined. The system then calculates a release time for each sheet from the feeder to insure the sheet avoids the seam on both belts.

Abstract: The present disclosure describes a method of automatically controlling feeding and transporting print media sheets through plural electrostatic print engines having seamed photoreceptor belts for duplex printing. In one embodiment the second photoreceptor belt is driven at a variable speed to maintain a constant phase relationship between the respective seams of the belts. The print image magnification on the front side of the printed sheet is matched by varying the speed of the scanner (ROS) in the second engine. In another embodiment. the first and second photoreceptor belts are both driven at a constant speed and the seam phase allowed to float. Sensors provide a timing signal upon passage of the seam in each belt respectively; and, the position of the belt seams thus determined. The system then calculates a release time for each sheet from the feeder to insure the sheet avoids the seam on both belts.