Canon MP640 Service Manual page 36

(9) Purge drive system unit (right plate) and switch system unit (left plate) removal
1) Release the springs of the carriage motor cable, duplex printing paper feed roller, cassette feed roller, cassette feed
guide, and paper guide unit (both sides). (See the Parts Catalog for details.)
2) Remove the springs (left and right) from the pressure roller unit.
3) Remove the screws that fix the units to the main chassis (2 on the right, 3 on the left).
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