Brother HL-3450CN Service Manual page 321

CHAPTER 8 TROUBLESHOOTING
I-15
Phenomenon
White spots and black spots appear on the print as shown in
Main Causes
(1) Foreign particles adhering to the OPC belt or transfer drum.
(2) The OPC belt or transfer drum is damaged.
(3) Foreign particles mixed in the toner.
(4) Foreign particles adhering to the transfer roller, or local deformation of the transfer roller.
Countermeasures
(1) Remove the OPC belt cartridge.
1-1)
1-2)
(2) Open the transfer unit, and check the transfer drum.
2-1)
2-2) Replace the damaged transfer drum with a new one. (See
(3) Remove the toner cartridge.
3-1)
3-2)
(4) Replace the transfer unit with a new one. (See
I-16
Phenomenon
Mixed color image appears in the print as shown in
Main Causes
(1) Failure of toner cartridge: Blade pressure of the developer roller is incorrect or the blade is
deformed.
(2) Restitution error of toner cartridge.
Countermeasures
(1) Confirm the toner cartridge can be inserted smoothly.
(2) Replace the toner cartridge with a new one.
(3) Reconfirm that the front cover unit is locked.
White Spot / Black Spot
Lightly wipe off the foreign particles adhering to the OPC belt using a cotton cloth.
Replace the damaged OPC belt cartridge with a new one. (See
Chapter 6.)
Lightly wipe off the foreign particles adhering to the transfer drum using a cotton
cloth.
Clean the surface of the developer roller.
Replace the toner cartridge with a new one.
Mixed Color Image
print sample (15) of Page
Section 4.6.1 of Chapter
print sample (16) of Page
8-58
8-46.
Section 4.1 of
Section 4.8 of Chapter 6.)
7.)
8-46.