A system of electrostatic recording

A new system of electrostatic recording in which electrical charges corresponding to the signal are injected into a thin insulating tape record has been investigated. The recorded charge pattern is produced by the application of ac or dc bias potentials to the recording electrodes, in addition to the signal voltage, and subsequently stabilized by treating the tape surface with ions to neutralize excess charge. Electrostatic recordings with extrapolated lifetimes in excess of several hundred years have been obtained.