Canon recently announced it has developed small-sized fuel cells, which could be put to use in some of its products such as digital cameras and printers within three years. The company is working on three prototypes, the largest of which will be used in compact printers. The mid-sized one will be suited for digital cameras, while the smallest model ?measuring 1.2 by 1.6 inches, will be aimed at even smaller mobile devices. The fuel cells Canon is developing differs from models being worked on by other companies in that they use a system that supplies hydrogen straight from a refillable cartridge instead of from methanol. The latter process emits carbon dioxide, while Canon's technology does not, making it more environmentally friendly.