Canon LBP-800 User Manual page 119

Never pull the paper out of the printer by pulling it forwards if the paper
is behind the face-down delivery rollers. This could result in damage to
the face-down delivery rollers.
Paper Jam in the Face-up Delivery Area
Please use both hands to remove jammed paper from the printer.
Follow the steps described in "Before Removing Paper Jams Inside the
Printer" on page 96 to remove the toner cartridge, then follow the
procedure below.
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Chapter 4 Troubleshooting