PURPOSE: To prevent a magnetic sheet from damage even if the sheet is left as its loaded state for a long period by fitting an expansion member made of shape memory alloy to a regulating plate driving member and separating the regulating plate from the sheet by thermal transformation at a time other than magnetic recording/reproducing.
CONSTITUTION: When a magnetic sheet pack 10 is inserted into a packet and an upper cover 28 is closed, positioning pins 68, 72 are inserted into holes 74, 76 of a regulating plate holder 60, a height regulating pin 80 is abutted upon the holder 60, the regulating plate 62 is lifted so as not to be contacted with the magnetic sheet 12. When an electric signal is outputted from a control circuit 92 to a regulating plate driving circuit 96, a heater 88 is turned on and a spring 84 consisting of shape memory alloy is heated more than a transformation temperature, the spring 84 is contracted, the pin 80 is pulled down and the holder 60 is descended to execute recording and reproducing. Since the pin 80 lifts the regulating plate 62 under the status other than magnetic recording and reproducing, a press trace or the like is not generated on the magnetic sheet 12 even if the magnetic sheet pack 10 is left as its loaded state for a long period.
AISAKA SHIGENORI
ASAMI KATSUO
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