| 摘要 |
A covering for sheet-supporting cylinders and drums on rotary offset printing machines for printing both on single and both sides of a sheet, the covering having a smooth surface on one side thereof and a textured surface on the opposite side thereof, with sheet-supporting surfaces projecting from the textured surface and formed of hydrophilic and chemically and wear-resistant material includes a device for defining perforations formed in the textured surface, and a device connected to the perforations for selectively applying blowing air and suction therethrough. |
