Canon BJ-10sx User Manual page 28

4. Press the POWER button to turn on the printer. The ERROR
light comes on because there is no paper in the printer.
5. Make sure the paper release lever on the right side of the printer is
pushed down. Paper will not feed correctly if the lever is up
6. Insert a single sheet of paper into the printer. Align the paper with
the paper size indicator on the left side of the top cover.