If, in fact, in the morning it's still kicking out "Imaging Unit Error" messages, we can try to find somewhere that will repair it, or we can replace it with something new.
So first, anybody able to suggest a good laser printer repair shop that will look at a decade-old laser printer and not just laugh?
Second, I'm looking at two possible replacements:
Xerox Phaser 6120N Laser Printer
Xerox Phaser 8500N Solid-ink Printer
The 6120 has a stiff discount at Costco, and is pretty cheap. The 8500 has a really big manufacturer rebate, and a lower per-page cost. It's also a hell of a lot faster.