Canon Color imageRunner C3220 Reference Manual page 48

I 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.
I Do not use flammable sprays, such as spray glue, near the machine. There
is a danger of ignition.
1
I This machine generates a slight amount of ozone during normal use.
Although sensitivity to ozone may vary, this amount is not harmful. Ozone
may be more noticeable during extended use or long production runs,
especially in poorly ventilated rooms. It is recommended that the room be
appropriately ventilated, sufficient to maintain a comfortable working
environment, in areas of machine operation.
I For safety reasons, turn OFF the control panel power switch of the
machine when it will not be used for a long period of time, such as
overnight. As an added safety measure, turn OFF the main power switch,
and disconnect the power cord when the machine will not be used for an
extended period of time, such as during consecutive holidays.
1-10 Installation Location and Handling