A device for reducing vibration of a main rotor having a support and a plurality of heavy elements and of rollers. The light control apparatus in the wireless light control system communicates with the wireless receiver via a wireless connection. Each of the substrate 1, the antenna coil 4, the bare IC and the sheet capacitor 3 is thinned, and the thickness of the entire apparatus is set to be equal to or thinner than 100 m. An optimum light amount to be emanated from the light source at the time of main-scan is set while changing the light amount from the light source and checking the outputs from the light receiving elements. If an edge is detected, then a sample is selected based upon the location of the detected edge and the next bit is set to the value of the selected sample.