Canon ImagePROGRAF iPF650 Series Service Manual page 150

Chapter 4
4) Remove one screw [1], move the cutter unit [2] to the left to release it from the protrusion [3], and then remove it rightward.
5) Remove two screws [1], and then remove the cutter [2].
4-16
[3]
[2]
[1]
F-4-34
[2]
[1]
F-4-35