| 摘要 |
The invention relates to a sheet delivery apparatus on printing presses which is fitted with pneumatically operating braking mechanisms and the function of which is to retard and tighten the merging sheet which is to be deposited. The pneumatic braking mechanisms may be of unipatite or bipartite construction and are fitted with braking rollers pressurized with suction air and adjusted to run on print-free areas of the printed image in order to prevent set-off of the newly printed underside of the sheet. In order to allow for adaptation of the braking force of the braking rollers to various types of paper and bearing in mind the varying width of the print-free areas of the sheet, depending upon the printed product, the braking rollers are disposed on a support shaft below the chain delivery and in front of the delivery pile and can readily be interchanged with others having wider or narrower sheet support areas. Depending upon whether the braking mechanisms are of unipartite construction as braking rollers having suction chambers and a vaccum feed integral therewith or of bipartite construction as braking rollers with separate slip-on suction members, the support shaft is of unipartite continuous construction or of multipartite and separable construction. |
