Canon Finisher-AB1 Service Manual page 271

Chapter 3
2) As needed, the staple unit is moved to empty itself of the waste staples in the waste staple case.
The machine's stapling sequence consists of the following operations: driving a staple, cutting the staple
tips, clinching the staple.
[1]Stack of sheets
[2]Staple
[3]Driving a staple
3-32
F-3-30
[4]Cutting the staple tips
[5]Clinching the staple