HP LaserJet M9040M9050 Multifunction Printer series - Manual (Page 223)

5. Remove the damaged staple.
Figure 12-57 Clear a staple jam from the stapler/stacker (5 of 9)
6. Press down on the lever labeled with a green dot.
Figure 12-58 Clear a staple jam from the stapler/stacker (6 of 9)
7. Reinstall the staple cartridge.
Figure 12-59 Clear a staple jam from the stapler/stacker (7 of 9)
8. Close the stapler unit door.
Figure 12-60 Clear a staple jam from the stapler/stacker (8 of 9)
ENWW Clear jams 209