HP Color LaserJet CP3520 Printer Series - Manual (Page 219)

Repetitive defects ruler
If defects repeat at regular intervals on the page, use this ruler to identify the cause of the defect. Place
the top of the ruler at the first defect. The marking that is beside the next occurrence of the defect
indicates which component needs to be replaced.
Figure 11-2 Repetitive defects ruler
0 mm
27 mm
32 mm
44 mm
66 mm
92 mm
105 mm
76 mm
77 mm
78 mm
80 mm
49 mm
50 mm
Distance between defects Product components that cause the defect
27 mm Print cartridge
32 mm Print cartridge
44 mm Print engine
49 mm Print engine
50 mm Print engine
66 mm Print engine
76 mm Print cartridge
77 mm Fuser
78 mm Fuser
80 mm Print engine
92 mm Print engine
105 mm Print engine
ENWW Solve image quality problems 207