Brother International HL-1070 Service Manual - Page 74

I-6 Black vertical streaks Black and blurred vertical streaks Possible cause Step Check Result Remedy Corona failure Corona failure Dirt in the paper feed system Scratch on the drum Cleaning failure Scratch on the heat roller 1 Is the corona wire dirty? Yes Clean the corona wire with the wire cleaner. 2 Is the vertical block streak about 10mm wide? Is the corona wire cleaner not in its home position? Yes Return the wire cleaner to its home position. 3 Is the paper tray or feed Yes Clean the toner off. system on the drum unit soiled with toner? 4 Is the drum surface scratched? Yes Replace the drum unit. 5 Is the drum surface dirty with toner in streaks? Yes Replace the drum unit. 6 Is the surface of the heat roller Yes Replace the fixing scratched? unit. HV.GND contacts (Fig.4-5) ➇ Note: Is you print the same pattern continuously, the drum will be worn away and black vertical streaks appear on the paper. I-7 Black and blurred horizontal stripes Possible cause Scratch on the drum Toner stuck on the developer roller Scratch on the fixing roller SR PCB Step 1 2 Check Are the horizontal stripes at 94mm (OPC drum) intervals? Are the horizontal stripes at 25mm (developer roller) intervals? 3 Are the horizontal streaks at 63mm (heat roller) intervals? 4 Is the problem solved after the SR PCB replaced? Result Remedy Yes Replace the drum unit. Yes Print several sheet and see what happens. The problem will disappear after a while. If not, replace the drum unit. Yes Replace the fixing unit. Yes Replace the SR PCB. IV-10