| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a positive-type or a negative- type lithographic printing plate which has a hydrophilic layer showing a high hydrophilic property, a strong bonding force with a support, and especially shows a remedied print scumming, and produces a scum-free printed matter even under severe printing conditions. SOLUTION: An original plate for a lithographic printing plate with a hydrophilic layer composed of a polymer compound which is chemically bonded with the surface of a support directly and has a hydrophilic functional group and an imaging layer, formed, in that order, on the support, is subjected to an image exposure. After developing the image, the surface of the printing plate is treated for protection with the help of a printing plate protecting agent containing a gum arabic which contains at least one kind of chelating agent. |
