Brother MFC6800 Service Manual page 152

Trouble
(12) Faulty image registration
(Leading edge of image starts
too late on paper)
(13) Image distortion or improper
image alignment
(14) Blurred at either side
At the printer side
Instruct the user not to load paper exceeding the limit in the ASF.
Instruct the user to use the recommended types of paper.
Replace the ASF.
Check the position of the registration sensor.
Replace the gear drive unit.
In communications
Check the following components:
- Error code displayed. (Refer to Section 6.1, "ERROR
INDICATION" in this chapter.)
- NCU PCB
- Main PCB
At the scanner
Check the following components:
- Document take-in roller, separation roller, and their related
sections
- Document feed roller and its related gears
- ADF motor and its harness
- Main PCB
At the printer side
Check that the laser unit is secured with the screws without
looseness.
Check the connection of the polygon motor harness.
Check the connection of the laser flat cable on the main PCB.
Replace the laser unit.
At the printer side
Check that the machine is placed on a flat surface.
Shake the toner cartridge horizontally. If the problem persists,
replace it.
Clean the laser beam window (glass) on the laser unit.
Replace the laser unit.
6 -2 5
Action to be taken