Charging system for electrophotographic copier - has outer photo conducting surface and charger arranged near to light responsive body to charge photosensitive body to predetermined surface potential

摘要

A high voltage supply (3) is connected to the charger (2). A surface potentiometer (4) is arranged near to the photosensitive body (1), to determine the surface potential of the body. A movable earthable dust tight cover (6) can be moved in to a position, in which it protects the potentiometer relative to the light responsive body. A control unit (5) compares the surface potential determined by the potentiometer (4) with the predetermined surface potential. The control unit regulates the high voltage supply, such that the determined surface potential is the same as the predetermined surface potential. ADVANTAGE - Prevents interference by foreign bodies e.g. toner adhering to potentiometer, affecting control and resulting in adverse effects on copy quality.