Quote from Canon FAQs...
The power light on the printer blinks continuously.
The printer does not recognize the installed ink cartridge. Either the ink cartridge is not seated properly or it is damaged.
With the printer turned on, open the front cover of the printer.
Release the locking lever that holds the cartridge in place.
Remove the cartridge from the printer and inspect it for damage or packing materials that may not have been removed.
Reseat the cartridge, let go of it, and lock the locking lever.
Turn the printer off, then back on again.
If the power light continues to blink after the printer has initialized, replacement of the ink cartridge may be necessary."