HP Scanjet Enterprise Flow N9120 Flatbed Scanner - Manual (Page 22)

6. Locate the white strip on the side ADF access door and the clear scan window inside the ADF. Wipe both of
these areas clean with a clean, damp, lint-free cloth.
7. Wipe the ADF rollers with a clean, damp, lint-free cloth.
Chapter 3
20 Care and maintenance