Magnetic recording medium having a surface with pores of specified average inlet diameter and wide pore size distribution controlled by calender treatment

摘要

A magnetic recording medium comprising a nonmagnetic support having formed thereon a magnetic layer containing ferromagnetic particles dispersed in a binder, wherein the surface of the magnetic layer has pores of (a) at most 50 Å in the average value of pore inlet diameters measured by a nitrogen gas adsorption method and (b) at least 25 Å in the half value width of the frequency distribution curve of the pore inlet diameters.