Secondary corona bound in paper printing channel below, will attract dust and scraps of paper, some corona components will become dirty or plugged, thereby preventing toner is transferred from the photosensitive drum onto a printing paper, also can cause the formation of a strip of white stripes on the printing paper. Toner cartridge failure, often leads to a large area of writing fades. Remove the toner cartridge gently shake, the box toner evenly distributed, if still not much, should replace the toner cartridge.