HP Color LaserJet Enterprise CM4540 MFP series - Manual (Page 135)

Replace the staple cartridge
1. Lift the gray latch on the front of the stapler,
and open the stapler cover.
2. Lift the green tab on the staple cartridge up,
and then pull the staple cartridge straight out.
3. Insert the new staple cartridge into the stapler
and push down on the green handle until it
snaps into place.
4. Close the stapler cover.
ENWW Replacement instructions 115