Canon PIXMA MX860 series Getting Started page 66

Slide the Paper Guide (E) to align with the mark of
paper size.
The Paper Guide (E) will stop when it aligns with the
corresponding mark of paper size.
w _
• There may be a little space between the Paper Guide (E)
and the paper stack.
Slide the Paper Guide (F) against left edge of the paper.
Confirm that the loaded paper does not exceed the line (G).
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• To print on specialty paper, be sure to load it in the Rear Tray.
Insert the Cassette (A) into the machine
until it clicks into place.