Magnetic tape apparatus for controlling a back tension of a magnetic tape running on a rotary drum

摘要

A magnetic tape apparatus includes a head which reproduces data from or records data onto a magnetic tape, taken out from a cassette, when the tape is running. A supply reel shaft rotates a supply reel to supply the tape from the cassette to the head. A take-up reel shaft rotates a take- up reel to wind the tape from the head around the take-up reel. A back tension applying mechanism has a brake part which presses the supply reel shaft to produce a braking force on the supply reel shaft, the back tension applying mechanism applying a back tension to the tape when the braking force is produced. A pressing force varying mechanism controls a pressing force of the brake part on the supply reel shaft such that the pressing force is maintained at an appropriate level for a type of cassette.