| 摘要 |
A printing method and apparatus for printing different indicia, such as account numbers, on selected documents without changing plates or stopping the press during a press run. Different indicia are provided at two or more lines on a printing plate, each line being separated from an adjacent line on the plate by a predetermined distance relative to movement of the plate in a press. The plate transfers images to a blanket having a region that does not contact the plate and thus receives no image of the plate area that registers with the noncontacting region of the blanket. The plate and blanket initially are aligned so that the noncontacting region registers with one set of indicia on the plate, so that the blanket receives a partial inked image lacking that indicia. That partial inked image is transferred to sheets passing through the press. A differential drive selectively displaces the angular position of the plate cylinder on the fly relative to the blanket cylinder, so that a different set of indicia becomes aligned with the noncontacting region on the blanket cylinder, whereby the blanket does not receive an inked image of that different set of indicia and following sheets are not printed with that indicia.
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