| 摘要 |
Sheets of rubber-coated fabric are mounted on the cylinders of offset printing presses. An under-packing formed from the combination of a flexible supporting sheet (12), which may however be dispensed with, and a multiplicity of flexible graded sheets (14) has to be interposed between the cylinder surface and the rubber-coated fabric to obtain a predetermined total thickness which varies as the type of printing press varies. The total thickness of the universal under-packing (10) according to the invention is equal to a predetermined maximum thickness. The thickness of the sheets (12, 14) of the universal under-packing (10) is chosen such that by removing from the universal under-packing (10) one or more graded sheets (14), the thickness which has to be obtained for any specific case can be sufficiently approximated to. That face of each of the graded sheets (14) of the universal under-packing (10) which, when the under-packing is mounted on the impression cylinder, faces inwards, but with the exception of the face of the most inner graded sheet (14) if the supporting sheet (12) is not present, is treated with a sticker of the type which, while maintaining the sheets (12, 14) united, enables them to be separated from each other. |
