Canon MG6650.How do I reset the ink pad counter ?

[4jbl7]

The MG6650 printer shows code 1700 - ink pads almost full. I have removed, cleaned and replaced them but cannot get the counter reset, code 1700 still shows. I tried the off/on hold etc simple method but no joy.
Does anyone have any idea what I might try to reset it ?
Thanks
Brian.