Dell C3765dnf Color Laser Printer - Manual (Page 480)

478 Maintaining Your Printer
8 Put your fingers through the loops on both sides of the transfer belt unit, and then pull it out.
CAUTION: If you cannot pull out the unit from the printer, make sure that all of the above procedures are performed
properly.
9 Clean the CTD sensor (as shown) with a clean, dry cotton swab.
Installing a Transfer Belt Unit
1 Unpack a new transfer belt unit.
2 Remove the two orange packing materials first, and then the protective sheet from the transfer belt unit.
CAUTION: Ensure nothing touches or scratches the surface (black-colored film) of the transfer belt unit. Scratches, dirt,
or oil from your hands on the film of the transfer belt unit may reduce print quality.