Using a thermal writing device, an image is drawn on an image-forming sheet that includes a base and a layer of microcapsules, coated over the base, containing microcapsules filled with a dye. The microcapsules are squashed under a predetermined pressure at a temperature falling in a predetermined temperature...http://www.google.fr/patents/US6246423?utm_source=gb-gplus-shareBrevet US6246423 - Manual thermal writing device for forming image on image-forming substrate
Manual thermal writing device for forming image on image-forming substrate
