Canon L90 - Manual (Page 140)

7-3
Maintenance
Interior
Clean the machine’s print area periodically
to prevent toner powder and paper dust
from accumulating inside.
1
Disconnect the power cord from
the machine.
2
Close the paper delivery tray
extension (A), and then the paper
delivery tray (B) itself.
Do not close the paper delivery tray without
folding the extension first.
3
Open the toner cover by the notch
(A).