Dell 3100cn Color Laser Printer - Manual (Page 210)

3. Press the levers on both sides and remove any jammed print media.
4. Return the levers to their original positions.
5. Close the BTR cover.
6. Close the duplex module.
When Not Using the Optional Duplex Module
1. Open the rear cover.
2. Open the BTR cover.
3. Open the paper cover.
CAUTION: The inside of the printer on the back side is hot.
NOTE: Never touch the outer levers located on both sides of the fuser unit, which are used to remove or install the fuser unit.
CAUTION: The inside of the printer on the back side is hot.