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Closed Loop Head Positioning Apparatus

IP.com Disclosure Number: IPCOM000078837D
Original Publication Date: 1973-Mar-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 47K

Publishing Venue

IBM

Related People

Grant, DE: AUTHOR [+3]

Abstract

This apparatus dynamically maintains accurate alignment between the multiple data tracks carried by a moving web of magnetic recording tape and the like number of transducing gaps of a magnetic read/write head.

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Closed Loop Head Positioning Apparatus

This apparatus dynamically maintains accurate alignment between the multiple data tracks carried by a moving web of magnetic recording tape and the like number of transducing gaps of a magnetic read/write head.

Tape 1 is shown in cross section. The tape is formed with a continuous, elongated transparent slit 3 running the length of the tape. When the tape is relatively wide, such as a number of inches, the slit is preferably placed along the center of the tape. The slit is not a physical discontinuity, but rather, is formed by removing the tape's magnetic oxide, as with laser energy, to form a slit 0.001 inch wide, or less. In the figure, the slit width is greatly exaggerated.

Head 4 is mounted on support 5 by way of piezoelectric transducer or motor
6. This motor is capable of moving the head normal to longitudinal tape movement, as indicated by arrow 7, in accordance with the electrical energization of the motor.

U-shaped member 8 supports a collimated monochromatic light source 9 on one side of slit 3, and two spaced photocells 10 and 11 on the opposite side of the tape. The photocells are spaced so that they do not receive any of the light which directly passes through slit 3. Rather, this spacing is such that photocells 10 and 11 view any of the higher diffraction orders which result, as the light passes through the thin slit. The photocells are positioned such that undesirable movement of the tape, in the transverse di...