example, a barcode): the outgoing voltage is constant while passing the white paper between two black marks, presents
a peak at each black mark and presents some “noise” at each barcode. In this case, the optimal value for the “Black mark
threshold” parameter is located about halfway between the peak value and the maximum value of the “noise”.
THERMAL SIDE
NON-THERMAL SIDE
Peak
“Black mark
threshold”
Noise
the “Black mark Threshold” at an intermediate point. In these cases, it is mandatory that the portion of paper between the
point of printing end and the front black mark is completely white (no graphics). In this way, the only next graphic detected
by the sensor for alignment after the printing end will be the black mark.
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