Fujitsu ScanSnap S1500M Operator's Manual page 441

10.
Attach the shaft.
Insert the right end of the shaft into the slot, and lower the other end gradually.
11.
Rotate the bushing (left) to lock the shaft.
Pick roller
Confirm that the pick roller is installed properly. Otherwise, paper jams or other feeding
errors may occur.
Shaft
Pick roller
441
Replacing the Pick Roller
Bushing
Shaft