| 摘要 |
PURPOSE:To ensure erasure by deciding the presence of unerased information and increasing the capability of the erasure means when unerased information exists to erase again the area having the unerased information in erasing the information recorded on a recording medium. CONSTITUTION:A reproducer head 5 irradiates a low output optical beam 103 on a magnetic film on a pre-group 2 erased by an optical beam 102, converts its reflected light into an electric signal and gives an output to a detector via a demodulation circuit 31. In inputting a detection signal from the detector 15, a controller 16 moves a recording head 4 and an auxiliary magnet 17 to the region where unerased information 104, 105 exist and applies erasure again. In this case, the erasure width is widened for erasure by using methods such as decrease of disc turning speed thereby extending relatively the irradiating time of an erasure beam and widening the temperature rise region or increase of erasure beam power. That is, surer erasure is attained by increasing the erased region for re-erasure. |
