Canon imageRUNNER ADVANCE 8500 series Troubleshooting Manual page 30

5) Remove the one connector and two screws to remove the staple collect unit.
6) Remove the tension spring [1], 3 clips [2] to pull out the shaft [3], and then remove the waste staple case bracket [4].
[Note] When removing the shaft, do not lose the bushing [1].
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