Lexmark C920 Service Manual page 107

Problem
Color fades with fuzzy, poorly
defined edges.
Toner adheres to the back of the
page.
Quality of printed
transparencies is inadequate.
L
Action
Print out a Menu Settings page, and check the level of supplies. If a
toner cartridge shows 10% or less, shaking the cartridge may improve
the printout.
Remove the cartridges and photodevelopers from the printer. Use a lint-
free, dry cloth to clean the LEDs of any stray toner. Wipe one at a time
and proceed from the front of the printer to the back in one gentle
swipe. It may take more than one pass. Use a different spot on the cloth
or a new cloth for each LED. Reinstall supplies and test.
Remove the supplies from the printer. Check that the LEDs are free to
move upward. With the supplies out, the metal post is visible on the
LED. Push up on the post, and make sure it returns to its previous
position. If the LED is binding, it is possible there is an incorrect screw
holding the cover in place. If too long a screw is installed in the cover, it
will bind against the LED. The correct screw length is 3.5 mm. Install the
screws and test.
Debris in the contact blocks may cause fading. Make sure there is
nothing in the contact block to keep it from seating securely when the
top cover is closed.
Ensure the absorption roll/charge roll on the belt is securely seated.
The black plastic T-shaped bushings should both be below the flap on
the right side of the belt. A poorly seated roll can cause both skewing of
the paper and problems with the magenta print.
Check that the top cover is firmly closed on the printer. If the cover is
not closed completely, the LED may be out of focus and allow light print
on the bottom of a letter size page. Close the cover firmly and test.
Print the quality pages in the Diagnostics Mode (under Print Test, Print
Quality Pages). This often identifies the color that has a problem. If you
switch the toner cartridges and the problem also changes color on the
test pages, the problem is in one of the cartridges. Replace the proper
color cartridge.
Remove the fuser oil roll, wipe it with a dry, lint-free cloth, and clean the
transfer belt. If there still is a problem, go to
page 2-68.
Be sure you're using the recommended Lexmark transparencies.
Be sure you have selected the correct paper weight setting for the
media you are using.
When printing transparencies, always set the Paper Type to
Transparency.
Avoid getting fingerprints on transparencies before printing.
5056-XXX
"Periodic dirt" on
2-65
Diagnostic information