Traveling-wave delivery of single-component developer

With the objective a controlled electrical delivery of single-component toner from a hopper to an image developing region, the traveling-wave induced pumping of dilute triboelectrified particles along the semi-insulating surface of a 100 mu m thick insulating layer is studied. Fabricated on a circuit board underlying the layer are electrodes connected to a six-phase high-voltage system so as to give a traveling-wave of 7 mm wavelength and frequency that varies from 1 to 100 Hz. Measurements of the migration of a band of particles, displaying synchronous and asynchronous pumping regimes, are compared to a theoretical model developed elsewhere. Provision for leakage of image triboelectrification charge is shown to provide for unipolar pumping. Synchronous pumping, with particles hopping along the surface in positive and/or negative bands displaced by a half-wavelength, is shown to prevail up to a critical frequency beyond which the well-controlled phase bands are replaced by a asynchronous motions that tend to be airborne.>