An electrophotographic machine includes a dielectric member configured for carrying a toner image. A transfer roller engages the dielectric member and transfers the toner image to an image substrate. A transfer roller power supply biases and periodically reverse biases the transfer roller. A transfer roller cleaning brush having conductive bristles engages the transfer roller. An electrically conductive brush housing encloses the transfer roller cleaning brush and defines an opening through which the bristles contact the transfer roller. The brush housing is electrically charged to the same electrical potential as said transfer roller and is selectively discharged.