| 摘要 |
PURPOSE:To make a copied image clear and easy to see by postexposing diazonium salt on image forming paper after heat development to cause whitening. CONSTITUTION:Photosensitive paper 9 as copying sheet is superposed on the image surface of original 10, and they are exposed with paper 9 downward by means of an ultraviolet flourescent lamp. Paper 9 is obtd. by coating base paper with a photosensitive heat-subliming composition and a sensitizer such as naphthol 9-2. The heat sublimability of naphthol is maintained in part 9-2-1 alone opposite to the image part of original 10 after exposure, and other part 9-2-2 is inactivated by exposure. Exposed paper 9 is superposed on image receiving paper 11 obtd. by coating base paper 11-1 as positive paper with diazonium salt 11-2, and by carrying out heat development, the heat sublimate in the unexposed part reacts with the diazonium salt and colors. Paper 11 is then exposed to ultraviolet rays to whiten the uncolored part of paper 11. |
