| 摘要 |
<p>PURPOSE:To prevent an erroneous detection of a mark of uncertain level, by outputting a mark as a bad mark when a light reflection factor of a mark is in an uncertain level. CONSTITUTION:An analog output signal of a photoelectric converting element 1 is divided into 2 kinds of signals having a high level and a low level by a variable amplifier 2, and when it is detected by both the levels that there is a mark, a mark output 7 is outputted but an uncertain mark output 8 is not outputted. In case when there is no mark at the time of amplification of a low level, and there is a mark at the time of amplification of a high level, the uncertain mark output 8 is outputted. In case when there is no mark at the time of amplification of both a low level and a high level, the mark output 7 and the uncertain mark output 8 are not outputted.</p> |
