Abstract: A tape roller bearing is provided that prevents the development of an air film between the roller surface and the tape. The spool surface is made from porous material so that air flows through the spool surface. The porous material vents air uniformly over the roller surface, and the tape remains in direct contact with the roller, even at high speed. The speed of the tapes movement can be determined by measuring the speed of movement of the spool surface using an encoder disk and an encoder module.

Abstract: An electric system utilizes dynamic impedance changes in windings of an electric motor to measure/monitor mechanical position. The method employs a bridge amplifier to measure voltage at a center node or windings against a voltage derived from a reference network. When a winding of the motor is driven, the winding forms a voltage divider across the center node. Impedance changes in windings occur as rotor poles pass by stator poles. The center node voltage varies with these impedance changes in legs on either side; this variation with respect to the reference network corresponds to measurement of rotational position. These measurements provide position/velocity feedback to a servo controller as long as current runs through a winding. This position sensing also applies to controlling commutation for brushless DC motor. Impedance measurement use normal motor-drive current for excitation without additional sensing signals, extra “sense” windings, or external sensors.

Abstract: A tape roller bearing is provided that prevents the development of an air film between the roller surface and the tape. The spool surface is made from porous material so that air flows through the spool surface. The porous material vents air uniformly over the roller surface, and the tape remains in direct contact with the roller, even at high speed. The inventive roller has many advantages, including improvement of tape wear characteristics, enhancement of tape guiding abilities, and increased tape speed stability.

Abstract: A cleaning device for a magnetic recording system that is mechanically actuated by a link to a loading device. A method of cleaning the recording head of a magnetic tape drive by bringing a brush into contact with the head by the movement of the loading device and by using the head actuator to move the head against the brush. A method to dynamically adjust the duration of the cleaning to the contamination.