| 摘要 |
<p>PURPOSE:To notify the lowering of detection capability of a photosensor due to deposit of dust and crud. CONSTITUTION:Photosensors 26 each consisting of a luminous diode detecting the existence of a goods in goods boxes 12 to 23 and a phototransistor are provided. Also provided are a controller 25 controlling the lowering of the luminescence intensity of the luminous diode in the state no goods is contained in the goods boxes and detecting the existence of lowering of the output level of the phototransistor at the moment and a letter indicator 24d indicating the lowering state of the photosensor detection capability when the controller detects no lowering of the output level.</p> |
