Hmm, okay.
I had tried to reset the printer already. The manual said to plug the power cord in while pressing down the cancel button and the left arrow button. I did as told. This didn't do anything to solve the problem for me.
I thought I'd try again for kicks, though. But before that I went to the printer's menu and selected Reset to Defaults.
I was reaching out to the back of my monitor, which is where I keep the surge protector, to unplug the printer's power cord once again, when I accidentally pressed the master power button for the whole protector. Needless to say, everything powered down - the printers, the computer, monitor, speakers, the PSX... Fantastic. Does wonders for the file system, I'm sure.
So I sighed and turned it all back on. The printer turns itself on, runs the initialization procedure
and starts printing the queue!
Produces a flawless colour printout of my wife in her bridal gown, which was the document I was trying to print, to test the printer.
Must've been the resetting to defaults via the panel menu.
I don't know how long it is going to work, but at least the unit is capable of printing flawlessly when it wants to.
Go figure.