Canon Perfect Binder A1 Troubleshooting Manual page 127

<For Perfect Binder-D1>
[CAUTION]: To close the Waste paper unit after mounting, rotate the Buffer drive pulley [1] to align the position of the Full detection
lever with the notch [3] on the Waste basket so that the Full detection lever [2] of the Waste paper buffer unit and the Waste
basket do not come in contact each other.
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