Laser printers need much power for heating. Would it be possible to switch to a ink printer? They should work fine on 10 to 20 Watts. They even have external Poweradapters like a Laptop.

It depends on the usagepattern. Not printing enough would dry up the ink. Printing to much could be to expensive or to slow.

But heating dust up with a laser to melt it down on paper seems to be very inefficient in terms of energyefficiency.