| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide the bar code reader which can start emitting a laser beam and driving a scanning optical system without making a user aware of the presence of a sensor and can also reduce an evil effect of misdetection. SOLUTION: A proximity sensor 8 receives reflected light from an article 20. A proximity sensor control part decides that the article 20 is present when the quantity of the reflected light received by the proximity sensor 8 exceeds a decision threshold value. The decision threshold value increases with the elapsed time from a read of a last bar code, and consequently the detection sensitivity decreases. When the proximity sensor control part decides the presence of the article 20, a CPU puts the lighting ratio of a laser light source which is decreased so far or stopped back to 100%, and restarts rotating a motor for driving the scanning optical system.</p> |
