Xerox WorkCentre 5020 Service Documentation page 62

Strobing (28mm or 14mm Pitch Density)
Cause
1. Developer Magnetic Roll bias.
Action
1. Replace the Drum Cartridge (PL 4.1) (REP 4.1.1).
Image Quality
Figure 2 Strobing (28mm or 14mm Pitch Density)
July, 2007
3-18
Initial Issue
WorkCentre 5020