(4) the drum is defective or installed incorrectly.
General repair methods:
(1) First check the drum eliminate electrical contact is good contact, maintenance is to change the original friction track contacts, and then coated with conductive grease can increase the conductivity.
(2) and then check whether the drum scraper lubrication (whether shear force is too large).
(3) There are many printer gear, then first adjust the drum main drive gear meshing, the gear may be appropriate to add some grease or oil, if more severe wear and tear can not be adjusted, replace the printer and drum main drive gear meshing can eliminate the fault.
(4) When the drum is defective, appears on the printed page horizontal black lines or smudges mostly with regularity, then can remove the cartridge carefully examined, if the drum is indeed a problem, you should replace the drum. If the drum is no problem, it may be due to the drum caused by incorrect installation.
