Surface potentiometer for use in an electrostatic copier

摘要

A surface potentiometer has a conductive shield housing provided in proximity to a body to be measured, a cage-shaped chopper rotatable within the housing, and an electrode disposed further inwardly of the chopper. The chopper is rotated to induce in the electrode a voltage corresponding to the potential of the body to be measured, thereby measuring the surface potential of the body to be measured.