Abstract: The attachment is selectively usable to apply heat, anti-offset powder, or both heat and powder to freshly printed sheets passing to the sheet collection station of a printing press. Operation of the heat and/or powder applying assemblies is changed automatically to compensate for changes in the press speed. The location at which heat is applied to the sheets is upstream from that at which powder is applied, and is spaced from the collection station. Shields and air currents assist in regulating heat transfer. A compact housing assembly supports both heat and powder applying components.

Abstract: The attachment is selectively usable to apply heat, anti-offset powder, or both heat and powder to freshly printed sheets passing to the sheet collection station of a printing press. Operation of the heat and/or powder applying assemblies is changed automatically to compensate for changes in the press speed. The location at which heat is applied to the sheets is upstream from that at which powder is applied, and is spaced from the collection station. Shields and air currents assist in regulating heat transfer. A compact housing assembly supports both heat and powder applying components.

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.