Wrong sign toner extraction for a direct electrostatic printer.

摘要

Direct electrostatic printing (DEP) is enhanced by the provision of wrong-sign toner extraction holes or apertures (38) provided in control electrodes (40) in a printhead structure (14) at a location which is upstream of the printing apertures. Wrong sign toner particles are extracted from a cloud of toner provided from a toner delivery device (12). The wrong sign toner is extracted from the powder cloud before the cloud reaches the vicinity of the printing apertures thereby minimizing print hole blockage.