ENTWICKLEREINHEIT FUER TROCKENTONER AN FOTOELEKTRISCHEN KOPIERGERAETEN

摘要

A magnetic brush monocomponent developer unit includes a doctor blade for rendering uniform the layer of toner magnetically attracted to the surface of a shell within which a rotating magnetic roller is positioned. A coil connected to the doctor blade receives an alternating magnetic field in response to rotation of the roller and the induced voltage fluctuations in that coil are sensed to determine when the voltage amplitude exceeds a given threshold value (indicative of a low amount of toner held back by the doctor blade) at which application of toner to the layer by way of a metering roller and sealing brushes is resumed.