Method of forming electrostatic image

摘要

A control electrode assembly is provided between a corona discharger and an electrostatic recording medium. The control electrode assembly has a pair of conductive electrodes interposing therebetween a insulating layer having a through hole extending from the upper conductive electrode to the lower conductive electrode. Selected one of the conductive electrodes is grounded through a change-over switch, which connects the selected electrode to the ground and disconnects the other non-selected electrode from the ground to electrically open it. Corona ions from the corona discharger charge the electrically opened conductive electrode to establish an electric field within the through hole. The corona ion current passing through the through hole can be modulated by operating the change-over switch to control the direction of the electric field established within the through hole in accordance with an image signal to form an electrostatic image on a recording medium.