Abstract: A cleaning device for an image forming apparatus includes a magnetic brush for causing a magnetic carrier and a toner to slindingly rub a surface of a photoconductor and removing the residual toner adhering on the photoconductor surface. The cleaning device further comprises a toner recovery assembly with a bias voltage applied thereto and for electrostatically attracting the surplus toner in the magnetic brush, a detector for detecting a toner density of the magnetic brush in terms of a magnetic permeability or a resistance of the magnetic brush and a bias voltage control means for controlling the bias voltage to be applied to the toner recovering system in accordance with a detected output of the toner density detector.