MAGNETIC TAPE AND ITS PRODUCTION

摘要

PROBLEM TO BE SOLVED: To reduce a drop-out at the time of reproducing while securing the traveling property by removing projections on the surface of a magnetic tape by friction with a lapping tape and suppressing the number of projections that are conspicuously higher than an average projection height to <= a specific value. SOLUTION: Projections existing on the surface of a magnetic tape having a rigid carbonaceous protective film 11 on a ferromagnetic metallic thin film 10 formed on a nonmagnetic substrate 9 and having a lubricant layer 12 on this protective film 11 are removed by friction with a lapping tape having the same lubricant layer. The degree of this removal in an integrated value of a histogram of the surface roughness is controlled so as to have the density of <=5×10<4> pcs/mm<2> of such projections that are higher than the projection height of 50% an integrated value by >=20 nm. Alternatively, after the projections existing on the surface of the ferromagnetic metallic thin film 10 formed on the nonmagnetic substrate 9 are removed to less than the above density by the friction with the lapping tape, the uniform rigid carbonaceous protective film 11 is formed by a plasma CVD method and moreover, so as to have the lubricant layer 12 on the protective film.