Canon IMAGEPRESS C7011VPS SERIES Operation Manual page 339

8.
Return the staple case to its original position.
When returning the staple case, always make sure that the staple case is inserted until the arrows
are aligned as shown in the diagram.
IMPORTANT
Follow steps 3 to 8 to replace the other staple cartridge in the saddle stitcher unit.
9.
Gently push the saddle stitcher unit (F-C4) back into the machine.
Always make sure to push the saddle stitcher unit in as far as it can go.
Replacing the staple cartridge in the saddle stitcher unit
Chapter 13 - Add toner and staples 339