DETECTOR FOR OBJECT TO BE TREATED

PURPOSE:To facilitate the mounting of a sensor while preventing malfunctioning, by mounting a photosensor to a container where a conveying unit is arranged to differentiate the reflectance of the conveying unit from that of an object to be treated significantly. CONSTITUTION:A photosensor 16 is mounted to a container 3 of a conveying unit 4 while the reflectance of the unit 4 is differentiated from test of an object 5 to be treated significantly. To this end, arms 7 and 8 of the unit 4, a setting plate 13 and a support base 6 is subjected to a black alumite processing and a high polymer black film is adhered on to surfaces of members to be brought close to the reflectance of the object 5 being processed. Therefore, the sensor 16 is allowed to detect the presence of the object 5 being processed positively without being affected by external light thereby elevating the reliability of the detection. The mounting work can be facilitated by mounting the sensor 16 outside the container 3.