| 摘要 |
PROBLEM TO BE SOLVED: To provide a method and an apparatus for offset printing wherein an alkaline developing liq. is unnecessary and plate processing is simple and quality of printing at a practical level wherein discriminating properties between imaging parts and non-imaging parts on a printed face are high and enough durability is provided and in addition, an original printing plate can be repeatedly used. SOLUTION: After the surface of a pair of a metal or a metal oxide with a characteristic where it is changed into hydrophilic property by irradiation of light or heating at high temp., is made hydrophobic, and after the surface is made hydrophilic into an image-like pattern to form image-like distribution of the hydrophilic region and the hydrophobic region, a layer of a water soln. contg. an org. film precursor and an electrolyte is provided on the original plate and by applying electric voltage between the original plate and the electrode plate provided by pinching the water soln. layer and facing to the original plate to form an org. film in the hydrophilic region and if necessary, a treatment for making the hydrophobic region hydrophilic is applied and the original plate for printing is brought into contact with ink to form a printing face where the org. film receives the ink. |
