Abstract: In first and second modes, the arrangement prints on only one side or on both sides of a sheet, respectively. A sheet is transported along a predetermined path through the arrangement and passes printing devices cooperating to effect printing of the sheet. Changeovers from one to the other mode alter a portion of the sheet transport path, changing its length. A control system for the arrangement includes a shift register. When a sheet arrives at a predetermined location along the path, a sheet-representing signal is applied to the shift register. Shifting pulses applied to the shift register in synchronism with sheet travel cause the sheet-representing signal to travel through the shift register in simulation of sheet travel. As the sheet-representing signal reaches preselected shift-register stages, it causes an actuator associated with such stage to actuate a respective printing device.