Methods and apparatus for full width printing using a sparsely populated printhead

Abstract

A multi-pass printbar for providing full width printing on a recording medium is provided. The full width printing may be achieved by stepping the printbar in increments corresponding to the combination of the array width of a printhead die and the gap spacing between the printhead dies until full width print coverage on the recording medium occurs. Ink is ejected from an array of orifices on the printbar as the recording medium passes under the printbar. Alternatively, the full width printing may be achieved by fixing the printbar, and its array of orifices, but stepping the document handler, for example a recirculating drum document handler, the recording medium is mounted upon as it passes under the fixed printbar. Yet another alternative provides full width printing by providing a combination of motions of the printbar and a recirculating drum document handler simultaneously such that the printbar moves continuously and at a constant rate in a linear fashion while the recirculating drum document handler rotates the recording medium under the linearly moving printbar. The result is a “barber pole” style placement of printing information ink droplets on the recording medium which occurs repeatedly due to the rotational recirculation of the recording medium on the drum under the linearly moving printbar until full width print coverage is achieved.