Hi bambuvn,
Thank you for using the Xerox forum.
I would suggest that you review the following detailed solution.
Solution : Clean the Laser Scan Unit (LSU)
http://www.support.xerox.com/support/3124/support/en_US.html?objGUID=1114
If that does not resolve your issue you may consider 1-posting additional details about the issue and things tried or 2-contacting our specific product support experts at the following link: Fast Track to the Expert