Yeah, I know the 600 series pretty well. They were the first single-ink printers for the desktop, in fact, I still have one here.
What you think is the print head is further disassembled into four actual print heads, assorted plastics, and a rubber joint.
On the bottom line, I've been selling and servicing printers for ages, and I've "done" all the Canon bubblejets ever since the first one, the BJ-10, came out. In that long time, over 15 years, I have learnt one thing: Canons don't die. In fact, I just come from replacing a handful of rubber transmission rings (28 cents each) from a BJ-230 that's been running daily for over a decade - and this was the first service this thing needed, ever.