I'm a hippy treehugger and I hate throwing something like this away, but why in the heavens would I spend that much fixing a printer that I can replace for $2999 after rebates, get a whole new set of ink cartridges and a new warranty.
I bought an iPF8000 when they first came out. Within the year Canon announced the iPF8100. I called Canon and asked, if I paid for packing & shipping both ways, would they replace the guts of my 8000 with the updated 8100. They declined. I even spoke to a customer service manager in my attempt to avoid EOL on my 8000. He understood but Canon had never planned on customers wanting to conserve on materials by swapping internals of their printers.
Within a year the iPF8000 had reached EOL. No more software support, firmware, and the cost of the heads was rising as stock depleted. I sold it for $1 on Craigslist to a Chicago graphics shop who was going to use it for parts. There was some satisfaction in that.
Given the size of these printers and
Canon's statement on "social responsibility", I'd think Canon would, at the very least, consider the path of internal upgrades.