| 摘要 |
<p>The printing machine has a common control device for at least two number printing mechanisms,. Each of them includes a signal character e.g. a dot, adjacent each print character, with an optical or mechanical unit for reading the print characters and signal characters printed on the paper web, by each printing mechanism. A comparator control receives the respective sets of signals representing the printed characters to verify that the same numbers are printed on the web by each printing mechanism. Pref. the comparator control has two counters, one of which counts up to a preset value during each parity check, while the other records the number of differences detected during each parity check, both counters reset when the first counter reaches its final value. If the second counter reaches a preset value which is less than that for the first counter, a signal indicating the lack of parity is provided.</p> |
