One or more toner cartridges may be defective.
Check the toner cartridges, and install new ones, if necessary.
Reinstall the OPC belt cartridge. If necessary, replace the OPC
belt cartridge.
Check that the printer is on a hard, level surface.
Reinstall the OPC belt cartridge. If necessary, replace the OPC
belt cartridge.
One or more toner cartridges may be defective.
Check the toner cartridges, and install new ones, if necessary.
If a wide horizontal white line appears,
Ensure that the transfer unit was closed.
Replace the transfer roller.