| 摘要 |
PURPOSE:To make fine the magnitization pitch of pulse signal and to produce high output by making the outer peripheral part of servo signal recording part of vertical magnetic alumite and to suppress the influence of leakage flux from a driving part to the servo signal recording part thus enhancing heat resistance. CONSTITUTION:A driving part 2 for rotating a capstan shaft 1 is composed of magnetic material and fit over a supporting disc 4. A servo signal recording part 3 for controlling the rotational speed of the capstan shaft is applied on the driving part 2. The servo signal recording part 3 is subjected to alumite treatment and then immersed in sulfate solution where irons are electrolytically deposited to produce a vertical magnetic alumite. Since pulse signals are recorded through magnetization in the thicknesswise direction of the vertical magnetic alumite, magnetization pitch can be made fine resulting in high output. |
