ROTARY MAGNETIC HEAD DRUM DEVICE AND ITS FIXED DRUM WORKING METHOD

摘要

PROBLEM TO BE SOLVED: To improve a contact characteristic between the magnetic head of a rotary drum and a magnetic tape by providing a projecting part in a belt- shape having an almost same height as the thickness of an air film on the tape separating side of the tape traveling surface of a fixed drum approximately parallel to the upper end surface of the fixed drum. SOLUTION: The fixed drum 3 on the lower side is formed with a lead surface L for guiding the magnetic tape and the belt-shaped projecting part 21. The projecting part 21 is continuously provided on the tape traveling surface 30 parallel to the upper end surface of the fixed drum 3 from a winding angle of the magnetic tape of about 130 deg. to an angle of separating the magnetic head from the magnetic tape up to about 200 deg.. The height of the projecting part 21 is formed to be about the same size as the thickness of the air film to be generated between the tape traveling surface of the rotary drum and the magnetic tape when the rotary drum is rotated at high speed. Thus, a distance between the magnetic tape and the circumferential side surface of the drum is kept nearly uniform on the traveling surface 30, and a reproducing output level of the magnetic head is made to be constant.