| 摘要 |
<p>PURPOSE:To stabilize and improve recording a reproducing characteristics by providing the opening or notch part of a magnetic recording meduim winding surface to a rotary drum and executing a correction to suppress a deformation due to the rotation of the rotary drum. CONSTITUTION:A rotary drum 1 is made of Al alloy, and its magnetic recording medium winding surface 3 is finished with high accuracy around the overall circumference. An opening or notch part 12 is a window for projecting a magnetic head or the window for drawing the magnetic recording medium. An inner circumferential surface 4 of the drum is a circular arc to share the same center 6 with the magnetic recording medium winding surface 3. To a worked inner circumferential surface 5, a shape correction is executed so as to minimize the deformation of the winding surface 3 when the drum 1 is rotated at the prescribed rotating speed. Thus, even at the time of the rotation at the prescribed rotating speed, the deformation of the winding surface 3 can be made uniform, the tightness of the drum 1 and the clamping part of a rotary driving system can be increased, and the deformation of the winding surface 3 can be minimized.</p> |
