| 摘要 |
PURPOSE:To prevent the deterioration in the S/N characteristic and picture quality of the titled medium by incorporating carbon black having 0.2-1.0% light transmittance at 9,000Angstrom wavelength and 10-30mmu primary mean particle diameter into a magnetic layer to the extent of 7.0-9.0wt%, based on the magnetic powder. CONSTITUTION:The carbon black having 0.2-1.0% light transmittance at 9,000Angstrom wavelength and 10-30mmu primary mean particle diameter is incorporated into the magnetic layer 2 to the extent of 7.0-9.0wt%, based on the magnetic powder. When the carbon black kept at <=5pH is used along with a binder to form a magnetic layer, etc., the mean surface roughness can be reduced to <=0.045mum, or preferably to <=0.040mum. Consequently, high S/N can be obtained.
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