I pulled the following statement RIGHT from the Manual for YOUR specific printer Hope it helps!
Eight flashes: Ink absorber is almost full
Ink used for cleaning is absorbed in a ink absorber inside the machine.
Press the RESUME/CANCEL button to dismiss the error message and continue printing. You can continue printing for a while, but once the ink absorber becomes completely full, you will not be able to print until the ink absorber is replaced.
Contact a Canon service representative as soon as possible to have this part replaced.