Lexmark C720 SERIES User manual

Using color
Paper handling
Maintenance
Troubleshooting
Administration
Printing
Index
Solving printing problems 1
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Lexmark C720
Some printer problems are very easy to solve. If your printer is not responding, first make
sure:
•The printer cable is securely attached to the printer and the host computer.
•The power cord is plugged into the printer and a properly grounded electrical outlet.
•The printer is turned on.
•The electrical outlet is not turned off by any switch or breaker.
•The printer front, top, and rear doors are completely closed.
•All printer options are properly installed.
Once you’ve checked each of these possibilities, turn the printer off and back on. This often
fixes the problem.
If a message appears on the operator panel display, see Understanding printer messages
for more information. If the message indicates the printer has a paper jam, see Clearing
paper jams.
If you are having trouble determining the source of the problem, see Print quality problems
for other suggestions.

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Solving printing problems 2
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Lexmark C720
The information in the following tables may help you solve printing problems. If these
suggestions do not correct the problem, call for service. You may have a printer part that
requires adjustment or replacement.
Toner cartridge problems
Problem Action
You cannot insert a toner
cartridge into the printer. Make sure the toner cartridge is aligned properly and is being installed in the correct location. See Replacing toner cartridges for
more information.
Toneraccumulatesinside the
printer. Replace the toner cartridge that matches the color of the toner that has accumulated inside the printer. See Replacing toner
cartridges.

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Solving printing problems 3
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Print quality problems
Problem Action
Print is too light, or printed
images or characters have
voids or dropouts.
Make sure the front, top, and rear doors are closed completely.
Make sure you’re using recommended paper or other media. Use
media from a new package.
Make sure you have selected the correct Paper Type setting for the
media you’re using.
If you suspect a toner cartridge is low on toner, remove the
appropriate cartridge and gently shake it back-and-forth to distribute
the toner evenly. Reinsert the cartridge and try printing the job again.
Replace the toner cartridge that matches the color on the page that
is too light or not present in the void areas. See Replacing the toner
cartridge.

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Solving printing problems 4
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Lexmark C720
Colored lines, streaks, or
smudges appear on the
printed page, or print appears
blurred or unclear.
Replace the toner cartridge that matches the color of the lines,
streaks, or smudges on the page. See Replacing toner cartridges.
Clean the photo developer discharger. See Cleaning the photo
developer charger.
Make sure the the drum cleaner is fully seated. See Replace the
drum cleaner.
The page has 100%
coverage of one color. Replace the toner cartridge that matches the color on the page. See Replacing toner cartridges.
Print quality problems (continued)
Problem Action

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Solving printing problems 5
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Lexmark C720
Light lines or streaks appear
on the printed page. Remove the toner cartridge that matches the color of the lines or streaks and gently shake it back and forth to distribute the toner
evenly. Reinsert the toner cartridge and try printing the job again.
Replace the toner cartridge that matches the color of the lines or
streaks on the page. See Replacing toner cartridges.
If the lines are black, you may need to replace the fuser. See Fuser
and air filter for more information.
Light lines or voids appear
from the top of the page to
the bottom of the page.
Remove the photo developer cartridge and clean the dust from the
photo developer cartridge discharger. (See Cleaning the photo
developer charger.) Reinsert the photo developer cartridge and try
printing the job again.
The toner cartridge may be low on toner, remove the cartridge, shake
it, and reinsert it. If the problem still occurs, replace the toner
cartridge. See Replacing toner cartridges.
Replace the photo developer cartridge. See Replacing the photo
developer cartridge.
Print quality problems (continued)
Problem Action

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Solving printing problems 6
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Lexmark C720
The page is blank or one of
the colors is missing. Replace the toner cartridge that matches the missing color on the page. See Replacing toner cartridges.
Toner smears or rubs off the
page. Make sure you’re using recommended paper or other media.
Make sure you have selected the correct Paper Type setting for the
media you’re using.
Make sure the rear door is completely closed.
Print quality problems (continued)
Problem Action

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Solving printing problems 7
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Lexmark C720
Toner adheres to the back of
the page. Make sure the paper size is set properly for the paper length you are printing on. Print several pages to clean the transfer roller of excess
toner.
You may need to replace the fuser. See Fuser and air filter for more
information.
Printed materials delivered
by the postal service arrive
with ghosting or mirror
images of the text visible on
the page.
When preparing printed materials for mailing:
•Use 24 lb (90 g/m2) paper.
•Avoid rough paper; select paper with a smoothness from 100 to
150 Sheffield points.
•Fold sheets with the text facing outward.
•Meter envelopes or use precanceled stamps.
•Place envelopes in trays and deliver to the post office; do not
drop envelopes into mail boxes or chutes.
Print quality problems (continued)
Problem Action

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Solving printing problems 8
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Lexmark C720
Quality of printed
transparencies is inadequate. Make sure you’re using the recommended Lexmark transparencies. See Transparencies for more information.
When printing transparencies, always set Paper Type to
Transparency.
Avoid getting fingerprints on transparencies before printing.
Print on the page is skewed. Make sure the width guides in the paper tray fit snugly against the
media you loaded. See Loading media for more information.
Print quality problems (continued)
Problem Action

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Solving printing problems 9
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Lexmark C720
Quality of printed images is
inadequate. If you’re printing low resolution images using PostScript 3 emulation, set Image Smoothing On. See PostScript Menu for more
information.
A white gap is noticeable
between color fills. Make sure the three printer foot pads are resting on a level surface.
Print quality problems (continued)
Problem Action

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Solving printing problems 10
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Lexmark C720
Colors do not print as you
expect. Make sure you have selected the appropriate Color Correction and Print Quality values for the job you’re printing. See Color Menu for
more information.
Print quality problems (continued)
Problem Action