Toshiba e-STUDIO2500c Operator's Manual page 361

5
Install a new staple case into
the staple cartridge.
Insert the new case into the cartridge
until you hear a click sound.
6
Install the staple cartridge onto
the stapler.
Insert the cartridge until it is caught by
the latch and fixed with a click sound.
7
Close the front cover of finisher.
If "Check staple cartridge" remains, repeat the above procedure from steps 1 to 7.
"Check staple cartridge" 359