Direct electrostatic printing apparatus with toner supply-side control electrodes

Abstract

A direct electrostatic printer having a printhead structure disposed intermediate a toner supply and a record substrate such that the control electrodes thereof are on the toner supply side of the printhead structure. The shield electrode is disposed on the side of the printhead nearest the record substrate. With this arrangement the control electrode is roughly four times more effective than prior art devices in repelling toner in the off state. Thus, a control voltage of 100 volts is sufficient to modulate the flow of toner through the apertures which previously required approximately 400 volts when operated in the normal forward direction. Also, wrong sign toner accumulates on the side of the printhead structure nearest the supply of toner thus, allowing for toner removal from the printhead structure and its return to the toner supply which avoids having to deposit the wrong sign toner on the recording substrate.

Dependencies are inferred from the claim text.