Canon imagePROGRAF iPF9000S User Manual page 738

Printheads
9.
If the ventilation duct (a) is dirty, use a damp cloth that you have wrung out completely to wipe it
clean.
Move the Carriage out of the way manually if Carriage is concealing the ventilation duct, and
then clean the duct.
10.
Lift the Carriage Cover to open it fully.
11.
Pull the Printhead Fixer Lever forward all the way to open it completely.
722 Maintenance