Epson has developed a print head that uses organic light-emitting diodes as the source of light. What the heck does that mean? Well if you want, you can read up on OLED over at Wikipedia, but in simple terms it is a type of technology similar to LED (light-emitting diode). Up until now, it had seen limited use in some displays like flat panel monitors or TVs. It is important because it is an improvement over the current LED technology. Epson would use it to produce smaller print heads that have brighter and more precise beams than their current laser printers feature. The article notes that it would allow them to make smaller laser printers and copiers which would be faster and print at a higher resolution.

Printers get a glimpse of OLED tech [CNET]