A shaft 17 defines a front end portion 17a having a larger diameter and an opposite tail end portion 17b having a smaller diameter, the shaft 17 being rotatably supported by the housing 13 through a radial bearing 19 and a pair of angular ball bearings 21 at the front side large diameter portion 17a and the small diameter portion 17b, respectively. A turbo encoder receives a sequence of L information bits, and generates the sequence of information bits and M sequences of L parity bits for the information bits, wherein M is determined depending on a transmission code rate. Finally, a phase control signal for carrying out a phase control is generated by using the obtained amount of correlations. An optical coupling layer is formed between the substrate and the first-conductivity-type semiconductor layer. The administrator terminal includes a part for reviewing the measured data stored and sorted out in the server. Thereafter, the user can take the printer calibration target and place it on the scanner and perform a calibration of a scannerprinter system.