Brother HL-2700CN Service Manual page 329

I-12 Banding
Phenomenon
Banding line appears in the horizontal direction as shown in
Main Causes
1) This is a transfer failure due to the uneven rotational speed caused by the shock
which occurs when the seam of OPC belt passes over the cleaning blade.
2) The OPC belt and the transfer belt fail to maintain the regular and proper rotation
due to the impact caused during the retract of the toner cartridge.
Countermeasures
1) Replace the belt cartridge PU with a new belt cartridge PU.
2) Replace the toner cartridge PU with a new toner cartridge PU.
Belt Cartridge PU
Belt Seam
Fig.8-8
VIII-72
print sample (12) of Fig.8-2.