| 摘要 |
A system for accurately controlling the start and stop positions for operations on conveyor-moved products, such as for applying glue lines, perforations or slits on sheets of paper, uses product position rather than timing to accurately control "on" and "off" operation positions on the product. The entry of a sheet of paper, for example, onto the conveyor path is noted by detecting the leading edge of the paper moving past an optical sensor. The location of the sheet is always known in a computer, due to conveyor position information continually fed to the computer. Distances which will be involved in the compensation times for the operating devices (e.g. glue heads) are calculated so that the gluing or other operation will be accurately located, but because the speed of the conveyor may vary, the "on" and "off" compensation distances are not calculated until just before the paper reaches the glue head, with current speed determined and applied to the known compensation times to calculate compensation distances.
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