| 摘要 |
PURPOSE:To facilitate the loading and unloading of a damping roller by providing a layer of a specific porous polyvinyl acetal based porous elastic material on the outer layer of a damping roller for offset press and fixing the elastic material on a rotating shaft. CONSTITUTION:A cylindrical polyvinyl acetal based porous elastic body roller is inserted securely into the rotating shaft of a damping roller so as to feed an appropriate amount of water evenly to a plate roller of an offset press. The polyvinyl acetal based porous elastic body is preferably 85-95% in the porosity, 10-200mum in the average pore diameter and 50-80mol% in the acetal orientation. With such an arrangement, a damping roller enabling a clear printing from the beginning is obtained eliminating the sewing at both ends thereof. To be more specific, a circumferential groove 16 is formed on the circumference of a cylindrical core 11 and a ring-shaped elastic body 12 is fitted into each groove. The cylindrical core is inserted into a through hole 17a of the cylindrical polyvinyl acetal resin elastic roller 17 and screwed down. The through hole 17a of the roller 17 is pressed from inside to fix a shaft member 11 on the roller 17. |
