HP LaserJet Enterprise 500 Color MFP M575 - Manual (Page 269)

Improve fax quality
Check the scanner glass for dirt or smudges
Over time, specks of debris might collect on the scanner glass and white plastic backing which can
affect performance. Use the following procedure to clean the scanner glass and white plastic backing.
1. Press the power button to turn off the product,
and then disconnect the power cable from the
electrical outlet.
2. Open the scanner lid. Align paper that has
copy defects with the scanner glass to identify
the locations of dirt or smudges.
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