Lexmark T520 - 20ppm 8MB Par USB Pcl6 Ps3 Ppds Service Manual page 122

4520-xxx
Print Quality - Background
Service Tip: Some background problems can be caused by rough
papers, non-Lexmark toner cartridges or if the media texture is set to
the rough setting.
Some slick or coated papers may also cause background. Some
problems occur with printers that run a large amount of graphics in a
humid environment. The customer may try to improve the print
quality by increasing the transfer setting.
Check the charge roll to make sure it is not at the end of life.
FRU
1 Printhead
2 Transfer Roll Assembly
3 High Voltage Contacts
2-94
Service Manual
Action
The printhead on the Lexmark T
printers cannot be cleaned. Try
another printhead if all other
attempts fail to correct a background
problem.
Check the high voltage contact from
the HVPS to the transfer roll. Check
the transfer arm assembly right side
bearing for any signs of
contamination, pitting or a loose
cable to the bearing. If any problems
are found, replace the defective part.
Check the transfer roll shaft for any
signs of contamination, wear or
pitting on the ends of the shaft that
go into the bearings. If a problem is
found, clean the ends of the shaft or
replace the transfer roll assembly.
Check the high voltage contacts on
the right side frame to ensure they
are clean and not bent, deformed, or
pitted. If incorrect, replace the
contact.