| 摘要 |
A fixed cutoff press is adapted to a variable cutoff press while maintaining thesize of the blanket cylinders. A plate cylinder is m ounted on a frame and includes a plate cylinder sleeve and a blanket cylinder is mounted on the frame, includ es with a gapless blanket cylinder sleeve. The gapless blanket sleeve contacts the pla te cylinder sleeve at a first nip. The press has an impression plate mounted on the fram e in the case of a non-perfecting press or an identical, mirror image assembly of plate an d blanket cylinders in the case of a perfecting press. A material to be printed passes through a second nip. Inkers are provided for transferring an ink film to the plate cy linder sleeve, the ink pattern being subsequently transferred to the blanket cylinder sleev e at the first nip and the ink pattern being subsequently transferred from the blanket cyli nder sleeve to the material to be printed at the second nip. The press also includes dri vers to drive in rotation the plate cylinder and drivers to drive in rotation the blanket cylinder. A controller is provided for controlling each of the drivers so that the surfa ce speed of the sleeve of the plate cylinder and the surface speed of the blanket cylinder s leeve are equal at the first nip. The plate cylinder sleeve is variable, whereby a length of an image to beprinted is varied proportionally to the variable outer diamet er while maintaining the outer diameter of the gapless blanket cylinder sleeve constant. Accordingly, since the size of the blanket is fixed and offset presses presently require changing p lates for each job, changes in cutoff are made in a manner similar to today, i.e. plates bu t not blankets are changed for each job. Ideally, the residual ink on the blanket, once the image is transferred to the web, is small enough that a secondary image will not appe ar on the web. The invention also provides for the inclusion of a blanket washer or sc rapper, which continually removes the residual ink and recirculates it through the i nk train to avoid any secondary images.
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