Xerox Phaser 7700 Service Manual page 131

Background contamination
There is toner contamination on all or
most of the page. The contamination
appears as a very light gray dusting.
The printer displays no error code.
1.
Ensure that the loaded media
matches the front panel settings.
In some cases, switching the paper
type setting, for example from
Heavy Laser Paper to Thin
Cover/Index, may improve
print-quality.
2.
Run the Calibrate for Paper
routine. From the front panel's
Support Menu, select Improve
Print-Quality?, then select
Calibrate for Paper Menu.
Note
Printing on some specialty
papers, such as some glossy
finish papers may show
background contamination.
3.
Inspect the print cartridges for contamination. Replace the print cartridges, if
necessary.
4.
If the Bias Transfer Roller or Belt Cleaner Assembly is near the end of its life,
replace that part.
5.
If the background contamination is a primary color (and that primary color is
missing from the print), the high-voltage wire leading to that color's developer
housing is grounded. Inspect the high-voltage wiring harnesses.
3-108 Phaser 7700 Color Laser Printer
3041-50