METHOD AND APPARATUS FOR DETERMINING THE APPLIED VOLTAGE AT WHICH PASCHEN BREAKDOWN OCCURS IN ELECTROGRAPHY

摘要

In electrographic printing Paschen breakdown must be exceeded for writing to occur, or the Paschen breakdown level can be used as a measure of the suitability of record media for use in such printing. The onset of Paschen breakdown is determined by the appearance or disappearance of second harmonic current flow across a test gap. The DC output of an integrator rises until the onset of Paschen breakdown occurs caused by the combination of the D C output and a sinusoidal voltage from an oscillator.