| 摘要 |
PURPOSE:To realize zero erasing with a DC system by forming two gap parts in the traveling direction of a tape, making the DC magnetic field generated in both reverse in poles and making the intensity of the magnetic field on the down stream side smaller than the intensity on the other side. CONSTITUTION:When DC current for erasing is supplied to the central winding part 12 of an erasing head device 7, erasing magnetic fields H0 having the polarities reversed from each other are generated in gap parts 11 and 11'. The intensity of such erasing magnetic fields and the magnetic flux density at a tape 6 attain a value B0 by way b1 b2 b3 b4 as shown in the figure. The residual magnetic flux B0 is erased by the following procedure: DC current is conducted to an auxiliary winding part 13 and the magnitude thereof is adjusted to adjust the intensity of the erasing magnetic field to be impressed on the tape 6 by the gap part 11' on the down stream side in the traveling direction from H1 to H'1 and the magnetic flux density in the stage of traveling is made zero by way of b1 b2 b'3 b4. |
