Direct electrostatic printing device (Dep) and printhead structure with low current flow between shield and control electrodes

摘要

An apparatus for direct electrostatic printing includes a back electrode and a printhead structure having a plastic insulating layer and printing apertures arranged therein. Individual control electrodes are combined with the printing apertures on a first side of the insulating layer, and a shield electrode is combined with the printing apertures on a second side of the insulating layer. A toner delivery apparatus is also included for delivering a cloud of dry toner particles in the vicinity of the printing apertures. The printing apertures are constructed and arranged such that, when applying a potential difference of 200V between the shield electrode and each individual control electrode, a current of no more that 50 mu A flows from each individual control electrode to the corresponding shield electrode through the corresponding printing aperture. Methods for forming the printing apertures in such a printhead are also disclosed.