| 摘要 |
PURPOSE:To improve the dispersing property of magnetic powder and electromagnetic transducing characteristics of a magnetic layer, by forming the magnetic layer in such a way that the magnetic powder is supplied to a sand grinder type mill and annular type mill and the magnetic layer is formed on a substrate by using the magnetic coating material adjusted by mixing and dispersing the magnetic powder together with a stirring medium. CONSTITUTION:A magnetic coating material 8 roughly mixed by means of a rough mixer B is supplied to the mixing tank 1 of a sand grinder type mill with a pump 10 and forcedly stirred together with a stirring medium 11 which is previously put in the tank 1. The magnetic coating material 8 is mixed and dispersed in the tank 1 by the impact force and slip stress of the medium 11 and discharged through a screen 5 to the next annular type mill C. The coating material 8 is further uniformly and finely mixed and dispersed by the shearing action of the stirring medium 11 in the mixing tank 22 composed of an endless inner and outer walls 20 and 18 of the annular type mill when the inner wall 20 is rotated. Therefore, when a magnetic layer is formed on a substrate by using this magnetic coating material, the dispersing property of the magnetic powder becomes good and its electromagnetic transducing characteristics become excellent.
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