Magnetic tape cassette having improved magnetic tape substrate and tape guide for reducing electrostatic charging

摘要

A magnetic tape cassette whose reliability is considerably improved by preventing triboelectrification by tape-and-guide friction. A metal tape guide for guiding the magnetic tape while in contact with the back surface of the tape. The substrate of the magnetic tape is made of polyethylene terephthalate or polyethylene naphthalate, and has a surface specific resistance Rs of 108 OMEGA /cm2 or more. The tape guide is made of stainless steel or aluminum, and the surface roughness of the tape guide is such that the root mean square roughness value Rrms, as determined by height from a reference surface, is 60 nm or lower. Also, the back surface of the tape may be provided with 30 to 400 protrusions of a height of 300 nm per 0.1 mm2.