Cassette half molding method therefor

Abstract

The cassette half molding method molds one of upper and lower halves of the magnetic tape cassette by injection molding with an injection mold in which a gas vent pin for smoothing a flow of molten resin to be introduced in the cavity for molding a transparent or semitransparent window portion provided in the upper half. The cassette half is molded by this molding method. The magnetic tape cassette has a friction sheet interposed either between a pair of take-up hubs and the upper half, or between the pair of take-up hubs and the lower half, or both, and the friction sheet is made of polyethylene-based resin and has a surface electric resistance value in the range of 1×107Ω to 1×1010Ω. The magnetic tape cassette has a rib for reducing a resistance when the roller of the detecting member passes through which is provided at a position corresponding to a recess and on a side of the front lid in the top surface of the body case.

Dependencies are inferred from the claim text.