Abstract: An electrophotographic printing machine, wherein an electrostatic latent image recorded on a photoconductive member is developed to form a visible image thereof, the electrophotographic printing machine including a system, for removing contaminants from toner in a developer housing, the system including a filter system, positioned in a path of flowing developer material, the filter system having a screen for permitting developer material to travel therethrough while inhibiting contaminants from traveling therethrough when vibrated; the screen being inclined to the path of flowing developer material a vibration driver, operatively connected to the screen, for vibrating the screen.

Abstract: An apparatus for powder cloud development of an electrostatic image in which a donor roll advances toner to a development zone adjacent the image, and in which precipitating electric fields are provided at the entrance and exit of the development zone to redeposit undeveloped toner onto the surface of the doner member, whereby unwanted airborne emissions of toner are substantially reduced.