MAGNETIC RECORDING MEDIUM, MAGNETIC POWDER AND FILLER POWDER USED FOR THE SAME AND MANUFACTURING METHOD FOR MAGNETIC RECORDING MEDIUM

摘要

PROBLEM TO BE SOLVED: To realize a magnetic recording medium having a coated layer (an under coated layer and a magnetic layer) excellent in durability and to provide magnetic powder and filler powder used for the magnetic recording medium and a method for easily realizing such a magnetic recording medium. SOLUTION: In the magnetic recording medium wherein the under coated layer and the magnetic layer are provided on a non-magnetic supporting body in this order, magnetic powder and filler powder which are subjected to prescribed surface treatment are used as the magnetic powder and the filler powder for the under coated layer. Surface treatment is performed in such a manner that the magnetic powder and filler powder are mechanically loosened and a surface treating agent is sprayed or dropped to the powder while the powder is stirred uniformly and slowly so that excess heat is not generated locally to make the surface treating agent uniformly adhere to the surfaces of the respective powder bodies. The magnetic recording medium having the coated layer excellent in durability can be obtained by using the magnetic powder and the filler powder thus obtained as a magnetic layer component and an under coated layer component.