Lexmark ST9820 User Manual page 115

Troubleshooting
Vertical dark lines or streaks
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
a
Check if the printer is using a genuine and supported toner
cartridge.
Note: If the toner cartridge is not supported, then install a
supported one.
b
Print the document.
Do vertical dark lines or streaks appear on prints?
Step 2
a
Remove, and then reinstall the imaging unit.
Warning—Potential Damage: Do not expose the imaging unit
to direct light for more than 10 minutes. Extended exposure
to light can cause print quality problems.
Warning—Potential Damage: Do not touch the
photoconductor drum under the imaging unit. Doing so may
affect the quality of future print jobs.
b
Print the document.
Do vertical dark lines or streaks appear on prints?
Step 3
a
Replace the imaging unit.
b
Print the document.
Do vertical dark lines or streaks appear on prints?
Yes No
Go to step 2. The problem is
solved.
Go to step 3. The problem is
solved.
Contact customer The problem is
support. solved.
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