Canon DR-2050SP - Manual (Page 76)

70 Appendices
4.
Shift the Retard Roller to the left to separate it from the shaft, and then remove
it.
Attaching the Retard Roller
1.
Position the retard roller so the notch in the roller is facing the scanner’s shaft.
2.
Slide the roller lock lever to the right, and then insert the shaft into the hole on
the left side of the retard roller.