Brother International MFC 8890DW Service Manual - Page 117

5. IMAGE DEFECT TROUBLESHOOTING 5.1 Image Defect Examples Light Faulty registration Dark Poor fixing Completely blank Image distortion All black Dirt on the back of paper Vertical streaks Black vertical streaks in a light background Black horizontal stripes White vertical streaks White horizontal streaks Faint print White spots Black spots Black band Downward fogging of solid color Horizontal lines Ghost Fogging Hollow print by condensation Fig. 3-5 5.2 Diameter of Rollers Image defects which appear periodically may be caused by failure of a roller. Specify the cause referring to the diameter of the rollers or pitch which appears in the image as shown in the table below. No. Parts name Diameter The pitch which appears in the image 1 Develop roller Ø20.0 mm 42.5 mm 2 Exposure drum Ø30.0 mm 94.2 mm 3 Heat roller in the fuser unit Ø25.0 mm 78.5 mm 4 Pressure roller ASSY in the fuser unit Ø25.0 mm 78.5 mm 5 Registration roller Ø14.0 mm 44.0 mm 6 Transfer roller Ø15.2 mm 48.2 mm 3-45 Confidential