Dell 3130cn - Color Laser Printer User Manual page 232

NOTICE: Ensure that nothing touches or scratches the surface (black-colored film) of the belt unit. Scratches, dirt,
or oil from your hands on the film of the belt unit may reduce print quality.
3. Pull up on the belt release levers and rotate the belt unit up as shown in the illustration.
4. Hold the latch of the duplexer as shown in the following illustration and pull out the duplexer from the printer.
5. Close the belt unit by pulling it down.
6. Close the front cover.