Even if you place originals in the ADF or on the exposure glass correctly, margin of a few millimeters on all four sides of the original might not be copied.
Missing Image Area
Leading edge: 4 ± 2.0 mm (0.16 ± 0.08 inches)
Trailing edge: 2 ± 2.0 mm (0.08 ± 0.08 inches)
Left edge: 2 ± 1.5 mm (0.08 ± 0.06 inches)
Right edge: 0.5 mm (0.02 inches) or more