Brother HL-3450CN Service Manual page 313

CHAPTER 8 TROUBLESHOOTING
I-3
Phenomenon
Uneven optical density appears periodically in the horizontal direction on the printed image as
shown in
Main Causes
(1) Failure of main motor.
i) Irregular rotation of the drive motor.
ii) Failure of the gears.
iii) Variation of OPC belt running speed due to above reasons.
(2) Failure of the OPC belt.
Countermeasures
(1) Replace the main motor with a new one.
(2) Replace the OPC belt cartridge with a new one.
NOTE:
If the print mode is set to CAPT (Color Advanced Photoscale Technology) in the driver, this
problem might occur. Change the mode setting to normal mode.
I-4
Phenomenon
Light print occurs on the right or left hand side of the image as shown in
Page 8-45.
Main Causes
(1) Slight tilt on the surface of printer
installation table.
(Tilt should be less than 1°.)
(2) Toner amount in the toner cartridge
is insufficient.
(3) Toner concentrates to one side in
the toner cartridge since the toner
cartridge is not level.
(4) The spring at the back of the
developer unit is deformed.
(5) The front cover unit is not firmly closed.
Countermeasures
(1) Confirm that the printer installation table is flat and level.
(2) Shake the toner cartridge horizontally several times to remedy the concentration.
(3) Replace the toner cartridge with a new one.
(4) Confirm the open/close position of the front cover to be firmly closed.
Jitter
print sample (3) of Page
Ribbing
8-45.
8-50
print sample (4) of
Fig. 8-6
1