HP Color LaserJet Enterprise CM4540 MFP series - Manual (Page 138)

Repeating defects
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 7-1 Repetitive defects ruler
0 mm
27 mm
32 mm
44 mm
55 mm
48 mm
51 mm
63 mm
76 mm
80 mm
96 mm
101 mm
Distance between defects Product components that cause the defect
27 mm Print cartridge
32 mm Print cartridge
44 mm Transfer unit
48 mm Print cartridge
51 mm Transfer roller
55 mm Print engine
63 mm Transfer unit
76 mm Print cartridge
76 mm Fuser
80 mm Fuser
96 mm Print engine
101 mm Print engine
118 Chapter 7 Manage supplies ENWW