Method and apparatus for making a mimeographic printing plate

摘要

A heat-sensitive material is used for making a mimeographic printing plate. The plate material includes a screen where printing ink is passable, and a resinous membrane formed on its surface. The resinous membrane is heated and melted so as to form a number of minute holes therein for passing the ink therethrough. A thermal head, having a large number of heating elements disposed in a main scan direction, is applied to the plate material. The plate material is moved in a sub scan direction by a predetermined distance, which is a pitch of a plurality of pixels on the plate material. In accordance with the optical density to be reproduced, the time of driving the heating elements is controlled in order to form holes in the pixels, so as to change a length of the hole in the pixels. As a result, the mimeographic plate for printing an image of half-tone can be obtained.