Abstract: The flash units are housed in reflector assemblies and actuated in a sequence that entirely exposes both sides of the sheet while drawing a constant amount of electrical power. Constructions of the reflector include an extruded housing, snap-in replaceable reflector surfaces, and a manifold structure that achieves cooling, fume scavenging and paper flattening. In one embodiment a two-sided sheet moves past a pair of oppositely directed flash units which are powered by a single power supply. A specularly reflective surface provides a level of reflected illumination which complements the light received directly from the flash tube to provide a constant level of illumination and fuse a toned image.