Lexmark MX721 User Manual page 240

Troubleshooting
Vertical dark lines
Note: Before solving the problem, print the Print Quality Test Pages. From the control panel, navigate to
Settings > Troubleshooting > Print Quality Test Pages. For non-touch-screen printer models, press
navigate through the settings.
Action
Step 1
Using a blank sheet of paper, make a two‑sided copy using the
ADF.
Do vertical dark lines or streaks appear on prints?
Step 2
Using a damp, soft, lint-free cloth, wipe the following areas:
•
ADF glass pad (A) and ADF glass (B)
•
ADF glass (A) and ADF glass pad (B) in door E
Do vertical dark lines or streaks appear on prints?
Yes No
Go to step 2. Go to step 3.
Go to step 3. The problem is
solved.
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