Canon MP970 Service Manual page 27

(5) Printer unit separation from the bottom case (how to remove the screw under the purge unit)
1) Rotate the purge unit gear toward the rear side of the machine to unlock the carriage.
2) Slide the carriage to the opposite of the home position (to the left).
3) Remove the screw.
<3-2. Special Notes on Repair Servicing>
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