20090141053 | Printing methods and apparatus - The identical printing of a stack of sheets (e.g., paper) is performed by vertically stacked inkjet printing units, each of which prints sheets at a printing speed. All sheets are fed from a stack along an infeed path at a feeding speed which is faster than the printing speed. The sheets are sequentially introduced into the respective printing heads, e.g., by the actuation of a gate mechanism disposed in the infeed path. After the sheets have been printed in the printing units at the slower printing speed, and after the print medium has been fixed, the sheets are discharged from the printing units and fed along a common outfeed path at the higher feeding speed. For variable-data printing, raster image processing is performed by assigned separate RIP computer units to process respective batches of the pages of the printing job. | 06-04-2009 |