Abstract: In a head driving device having an optical head for erasing, recording and reproducing information, a carriage adapted to move in a radial direction of a disk as an information recording carrier together with the optical head, and voice coils attached to the carriage and imparting a thrust to the carriage in cooperation with a magnetic circuit, wherein tracking for a disk track deflection is performed by only a linear actuator comprising the magnetic circuit and the voice coils, a working center line of forces applied to the voice coils is set as so as to extend on the disk side with respect to the center of gravity of the moving portion. By so doing, a tracking servo system does not become unstable even when the working center line of forces exerted on the voice coils and the center of gravity of the moving portion are deviated from each other.

Abstract: An optical disk apparatus in which a head is accommodated in a movable part which moves the head along a guide shaft in a radial direction of an optical disk. The guide shaft is engageable with the movable part and extends in the radial direction of the optical disk. The optical disk apparatus has a guide shaft compression mechanism which applies a compression force toward the movable part, which force is distributed, approximately uniformly, along the radial direction of the optical disk, to the guide shaft so that the movable part can be properly engaged with the guide shaft so as to move smoothly and stably along the guide shaft in the radial direction of the optical disk.

Abstract: A disk storage device includes a head part which writes data into a storage disk loaded into the disk storage device and reads data from the storage disk, a linear actuator moving the head part in radial directions of the storage disk, an eject member which is operated when the storage disk is ejected, and a movement mechanism which moves the storage disk to an eject portion in response to an operation of the eject member and which moves the storage disk to a read/write position. A lock part, which has a lock member cooperating with the movement mechanism, keeps, in response to the operation of the eject member, the head part stationary at the eject position by the lock member which engages with one of the head part and the linear actuator.

Abstract: A magneto-optical disk storage has an erroneous insertion preventing mechanism which projects into a holder so that it can touch the magneto-optical disk cartridge in order to prevent the same from being inserted. The erroneous insertion preventing mechanism mechanically engages with the magneto-optical disk cartridge and moves in a direction approximately vertical to the recording suface of the magneto-optical disk to allow the magneto-optical disk cartridge to be inserted only if the magneto-optical disk cartridge is being inserted into the holder with a correct orientation.

Abstract: An optical disc in which distortion due to temperature change is inhibited has a magnetic positioning disc 3 of specified diameter mounted at the center of the disc substrate 1 having an information recording layer 2 on a specified radial area. The positioning disc is bonded to the disc substrate by an element(s) made of a material whose thermal expansion coefficient is almost equivalent to that of the disc substrate.