Canon IMAGERUNNER 5075 Reference Manual page 355

CAUTION
When returning the locking lever to its original position, be careful not to
get your fingers caught, as this may result in personal injury.
IMPORTANT
Make sure to return the locking lever all the way to the 'Lock' position. (Otherwise,
the toner cartridge will not be inserted properly.)
6
Close the toner replacement cover.
CAUTION
When closing the toner replacement cover, be careful not to get your
fingers caught, as this may result in personal injury.
Replacing the Toner Cartridge
7
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