抄録
Printing has been one of the most important technologies in thousand years because of the reproduction of the Bible. Printing plates called pre-sensitized plate are not familiar compared with ink, paper and printing machines, but have an important role in printing technology. In offset printing, two different zones, ink-acceptant and water-acceptant areas, produce images. Water and ink are supplied to the plate in printing simultaneously and then transferred to paper. This is the essence of offset printing technololgy. Since the thickness of image area is about 1 micron (1/1000 mm), the offset printing is said to be a subtle surface technology. Usually surface-treated aluminum is used as non-image area and photo-sensitive polymers are used as image area. Advances of computer and laser technologies increase dynamically the demand of new plates called CTP (=Computer To Plate) in the printing market.
