According to Vnunet, Toshiba has developed a printer (B-SX8R) that can erase and reprint — up to 500 times — on a single sheet of paper. Video after the jump.
Toshiba’s process uses a special pigment in the paper that reacts to heat. If heated above 180 degrees centigrade the pigment turns black, creating an image on the sheet. However, if the surface is heated to between 130 and 170 degrees the pigment reverts to white, allowing the image to be ‘erased’