Canon LBP3460 User Manual page 186

IMPORTANT
Do not hold the toner cartridge in a manner that is not directed in this procedure.
8
Push the toner cartridge into the printer until it touches the
back of the printer while aligning (A) on both sides of the
toner cartridge with the toner cartridge guides inside the
printer.
6
(A)
(A)
Replacing the Toner Cartridge 6-15