To provide a planographic printing method which makes an image directly recorded from digital data of a computer etc. by means of an original plate for a planographic printing plate, capable of recording the image by using a laser emitting infrared rays, which makes on-machine development performed without a developing process, and which can bring about many properly printed matters by a practical amount of energy.
This planographic printing method includes a process wherein printing is done by the supply of a water-based component and an oil-based ink, without going through the processing process, after the original plate for the planographic printing plate is exposed in an image-wise manner by using an infrared laser. In the original plate for the planographic printing plate, an image recording layer capable of recording the image by infrared irradiation, which is provided on a substrate, contains: an infrared absorbent (A) as a cyanine dye which has a condensed ring of a nitrogen-containing heterocyclic ring and an aromatic ring or a heterocycle and wherein an electron-withdrawing group or a heavy atom-containing group is provided in the aromatic ring or the heterocycle; a radical generator (B); and a radical polymerizable compound (C).
NAKAMURA IPPEI
Haruko Sanwa
Hiroshi Fukushima