MOVING WIDTH SWITCHING TYPE HEAD FEEDING DEVICE

摘要

PURPOSE:To obtain a high-density track recording and reproducing device which can switch the head moving width between a quadruple-density track and standard-density track without changing its head moving mechanism and can be reduced in size and cost while its compatibility is secured with an existing standard-mode recording medium. CONSTITUTION:A moving width switching type head feeding device is provided with a two-phase bipolar excitation stepping motor 7 which moves a head along a recording medium and sequential pulse forming logic circuit which receives a head movement commanding pulse DIR and track density controlling signal X4 and forms sequential pulses for two-phase bipolar excitation. Then a first operation mode in which the logic circuit operates in accordance with exciting phase transition in which the logic circuit alternately performs excitation of the two-phase coils 72a and 72B of a the motor 7 in one phase only and simultaneous excitation of the coils 72A and 72B in two phases at every head movement commanding pulse in accordance with the track density controlling signal X4 and exciting phase transition composed only of the two-phase simultaneous excitation are switched to each other at every head movement commanding pulse.