Canon is developing fuel cell technology for use in printers and digital cameras. Fuel cells are generally more efficient than traditional batteries, but the size/performance ratio isn't quite where it should be:

Canon, the world's top maker of copiers and cameras, is aggressively investing in the development of new products, keen to cultivate new growth drivers as the digital camera market slows and competition in the printer and copier markets heats up.

This news article was written on October 25, 2005, quoting Reuters.