Canon CLC5151 Reference Manual page 48

Be careful not to spill liquid or drop any foreign objects, such as paper clips
or staples inside the machine. If a foreign object comes into contact with
electrical parts inside the machine, it might cause a short circuit and result in
a fire or electrical shock.
1
If there is smoke, or unusual noise, immediately turn the main power switch
OFF, disconnect the power cord from the outlet, and call your local
authorized Canon dealer. Using the machine in this state may cause a fire or
electrical shock. Also, avoid placing objects around the power plug so that
the machine can be disconnected whenever necessary.
OFF
Do not turn the main power switch OFF or open the front covers while the
machine is in operation. This might result in paper jams.
1-8
Installation Location and Handling