An image forming apparatus including a plurality of image bearing members, an electrostatic image forming device for forming an electrostatic image on the image bearing members, a plurality of developing devices for developing as developer images the electrostatic images formed on the plurality of image...http://www.google.com.tw/patents/US7693441?utm_source=gb-gplus-share專利 US7693441 - Image forming apparatus including a toner removing device operable in two modes for removing residual toner on an intermediate transfer member
