The figure shows a Finisher FS-534 with Saddle Stitcher SD-511 and Punch Kit PK-520 installed.
Do not remove staples that remain in the machine. Otherwise, the stapling function will activate but no sheets will be stapled.
Be sure to replace the Staple Cartridge after the relevant message has appeared. If a Staple Cartridge is removed before the relevant message appears, it may result in a failure.