Apparatus for controlled delivery of magnetic toner

摘要

A developing apparatus for developing an electrostatic latent image by means of a magnetic toner. The apparatus includes a non-magnetic cylindrical sleeve accommodating a first magnet roll and disposed to face the surface of a photosensitive roll, a developing tank for supplying the non-magnetic sleeve with the magnetic toner, and a blade disposed at the outlet of the developing tank for adjusting the thickness of the magnetic toner which is conveyed on the surface of the sleeve due to a relative rotation between the sleeve and the first magnet roll. The apparatus further includes a detector disposed at the upstream side of the blade as viewed in the direction of convey of the magnetic toner for detecting the amount of the magnetic toner, a second magnetic roll disposed at the toner outlet of a toner tank for controlling the amount of the magnetic toner supplied through the toner outlet to the developing tank, and a motor for selectively rotating the second magnetic roll in accordance with a signal produced by the detector.