Having had a few queries about this over the past few months I opted to write an article on the experience and issues that anyone looking to modify a Pixma will face.
http://www.octoink.co.uk/store/pages/Canon-Pixmas.html
_________________
Printers: (Canon) MP500/830, MX700, iP4000/4200/4300/4500/5200, iX4000(A3) (Epson) C84/86, D88, CX6600, R285/800/1900 (HP) K550, K850, K5400, L7680