Ricoh D131 Service Manual page 1327

Booklet Stapler Unit
2. Attach the special tool [A] and reattach the booklet stapler stay.
This tool is included with the stapler spare part.
3. Turn the gear [B] with your finger until it stops.
4. Tighten the screws to attach to the booklet stapler motor.
5. Remove the stay again and remove the special tool.
6. Reattach the booklet stapler stay.
7. Push the stapler unit into the machine.
SM 21 B804/B805/D373/D374/D612