I have the same printer & it does use a lot of ink as, you may have noticed yourself, it cleans the heads every time before printing something.
Leaving it switched on seems to help - see my related thread at click here, where I was advised to do this. And the set of re-manufactured cartridges purchased off eBay aren't doing too bad either - better than the original ones anyway. I paid just under £10 for a full chipped set.
A similar problem reported with other Canon printers in this PCA thread click here. Canon were supposed to get back, but haven't yet. See my post there at click here (2nd from bottom) & the FE's post just below mine.
And another similar problem reported elsewhere with our printer at click here. G