| 摘要 |
PROBLEM TO BE SOLVED: To efficiently remove the static electricity of a magnetic disk by providing the inside and outside edge parts of a holding member with curved surfaces and coating the inner peripheral surface of the contact surface with the magnetic disk with a conductive ceramic film. SOLUTION: A spacer 11 consists of an annular body 112 and the tapered surfaces or curved surfaces having a width of 0.04 to 0.5mm are formed on the inside and outside edges 114a, 114b thereof. The contact surface 113 of the spacer 11 has surface roughness to prevent the spacer from turning accompanying the high-speed rotation of the magnetic disk and has a prescribed flatness to obviate the occurrence of a strain in the disk. The entire surface of the annular body 112 is coated with the conductive ceramic film 115 having a specific volumetric resistance value of <=1×10<7>Ω.cm and a coefft. of thermal expansion of 6 to 10×10<-6> / deg.C at a film thickness in a range of 0.1 to 3μm. Consequently, the efficient removing of the static electricity electrified on the magnetic disk is made possible.
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