| 摘要 |
<p>The invention provides a method of detection of an imprint of a postal indicium at a location on a mail piece (26) comprising the steps of utilising a sensor (35) to scan along a band (43) on the mail piece (26) to detect a sequence of transitions between light and dark reflectance areas within said band (43), said band (43) extending across said location; generating an indication of presence of the imprint of the postal indicium (25) in response to detection of a transition succeeding a predetermined number of initial transitions at a start of the sequence of transitions. Also provided is apparatus for imprinting postal indicia (25) on mail pieces (26) comprising printing means (23) operable to print a postal indicium (25) in a required location on the mail piece (26); a first sensor (35) responsive to reflectance transitions between light and dark along a band (43) of the mail piece (26) extending across said location to generate a sequence of first signals corresponding respectively to reflectance transitions along said band (43); means operative in response to a first signal occurring after a predetermined number of said first signals at a start of said sequence to generate a second signal indicative of a postal indicium imprint on the mail piece. <IMAGE></p> |
