Canon MP240 print cartridges refill

From what I have heard, all you have to do is hold down the stop/reset button for 6 seconds. The black ink light will still flash, indicating the printer thinks its low, but it will print anyways.

If that doesn't work, try this:
1. Start with printer off
2. Press and hold resume Button (triangle in the circle) and click “Power” button. Green led should be on
3. While holding the Power button, release the Resume Button.
4. Without releasing the Power Button, click “Resume” button for two times and release Both Buttons.
5. Click “Resume” for four times then soon click “Power” button, to confirm the selected action (reset counter absorber).
6. Turn off the printer and turn on again

source: http://www.quora.com/How-do-you-reset-Canon-MP240-printer-after-refilling-ink-cartridges