Abstract: Freshly printed sheets are sprayed with antioffset material while being transported from the printing station to the sheet stacking station of a printing press. The control circuitry for the spray apparatus includes a sensor for detecting and signalling the location of successive ones of the sheets, and timers whose timing periods determine when each cycle of operation of the spray apparatus is initiated and terminated. The time periods are manually adjustable by potentiometers associated with the timers, and are automatically and compensatingly adjusted in response to changes in the press speed. Operation of an air compressor component of the spraying apparatus terminates automatically after spraying of the final printed sheet of a press run.