| 摘要 |
PURPOSE:To easily check abnormality in the rotational drive of a magnetic sheet, by detecting the rotating speed of the magnetic sheet by means of the 1st yoke and 1st detector and the rotating speed of a driving motor with the 2nd yoke and 2nd detector, then, comparing the detected two rotating speeds with each other. CONSTITUTION:The 1st PG yoke 50 is buried in the center core of a magnetic sheet jacket and the 1st detector 60 is provided under a condition where the detector 60 is faced to the yoke 50, then, the magnetic pulse signal of the PG yoke 50 resulting from the rotation of a magnetic sheet is detected. On the other hand, the 2nd PG yoke 75 is installed to the driving shaft 7 of a driving motor and the 2nd detector 65 is provided under a condition where the detector 65 is faced to the yoke 75, then, rotational pulse signals resulted from the rotation of the motor are detected. After the signals of the 1st and 2nd detectors 60 and 65 are amplified in pulse, both rotating speeds are compared with each other at a comparator. Therefore, abnormality in the rotational drive of the magnetic sheet can be checked easily. |
