HP Color LaserJet 8500 Service Manual - Page 467

CAUTION Transfer roller Symptoms: Print defect occurring every 66 mm. Cause: Dirty or damaged transfer roller. Actions: Clean the transfer roller with isopropyl alcohol and a hand wipe. If cleaning does not resolve the defect, replace the transfer belt. Transfer drum Symptoms: Print defect occurring once per page on 11-by-17-inchor A3-sized media, or on every other letter- or A4- sized page. Cause: Dirty or damaged transfer drum. Actions: Clean the transfer drum (see below). If the defect is not resolved by cleaning, replace the transfer drum. Cleaning the transfer drum Many, but not all, repetitive defects can be removed using the following procedures. Defects that appear as light spots in dark areas of print are more likely to be corrected by this procedure than dark spots in unprinted areas. If the procedures are performed incorrectly or without proper care, the transfer drum can be permanently damaged. CAUTION This procedure requires the following items:
a print sample showing the repetitive defect
a clean, flat surface on which to work
a hand wipe You can also use a dry, clean, soft, lint-free cloth, such as cheesecloth, to clean the transfer drum. To prevent scratches on the drum, do not use any paper products (such as tissue or paper towels) to clean the drum. EN Repetitive defects troubleshooting 465