I have a HP Deskjet 350CBi "Mobile Inkjet Printer". Runs off a NiCad pack which can be charged from a 100-240V~ source. I'm sure that with some fiddeling it can be made to work off 12v as teh charger's output is 10.6vDC.
I have a canon bjc85, very small and compact, colour and photo quality, runs off mains and luckily uses 13 volts dc from the power supply, so is ideal to run straight from the ships supply, which mine does, without problems. Its a proven printer, we use them offshore all the time and have had no problems with them. They are being superceded at the moment, so deals should be available. Just as an aside, you can fit a special cartridge in the printer cartridge carrier, which turns it into a plotter aswell, I haven't got that facility yet, but intend to get one.
I'm using a small Citizen Notebook printer on board. Works with a thermal tape, hence the printout is water resistent. It's very small, but you can't print photos with it, like with some of the ink based ones. Not sure Citizen still makes them. Bought mine used on e-bay for about £25 with a dead battery, but I ran it from ship DC anyway.
I've had two Canon ink-jets on board, first a monochrome portable, now a colour BJC-2000, for a total of 11 years. Never a problem. In harbour I keep the printer on the chart table, running off a small Heart marine inverter (325 Watts continuous). At sea I stow it in a cheap canvas bag in a dry place. The ink costs more than the printer, but for occasional use that doesn't matter. Don't bother with the "portables". They cost more and aren't worth it. Good luck.