| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for offset printing with which an original printing plate is easily made up without use of an alkaline developing solution and with a print quality improved at a practical level in distinguishability between an image part and a non-image part of a printed face, and can be repeatedly used. SOLUTION: In this method and an apparatus for offset printing, the original printing plate is made hydrophilic when heated at a temperature required for developing high temperature hydrophilicity. Then, on a surface of the plate a hydrophobic image area is formed by imagewise coating with an ink-jet method a solution including a chemical compound expressed by GnJM4-n (G is a hydrophobic organic group; J is an element with an atomic value of 4 selected out of C, Si, Ge, Ti, Zr, and Sn; M is halogen or an alkoxy group; and (n) is an integer of 1 to 3). A method and an apparatus for reusing the original printing plate after the surface of the plate used is cleaned so that the remaining ink is removed are also provided. |
