Abstract: In an electric motor unit, a spindle is rotatably supported by bearing sections of a dynamic-pressure type, and is floated along its axis by a magnetic thrust bearing. At the bearing sections, air current layers are formed in the gaps between journals of the spindle and bearings by elongated parallel grooves formed along the axis, and the spindle is supported by pressure distributed over the air current layers. In the thrust bearing, rotor magnets fixed to the spindle are attracted to stator magnets fixed to the housing and surrounding the rotor magnets. The spindle is floated along the axis by the attraction between the magnets.

Abstract: The invention provides a case for housing information memory media therein, having a base sheet which is integrally constituted by a first case section, a second case section and a third case section through a first connecting portion and a second connecting portion. The first and second connecting portions which are included in the third case section can be folded. When the base sheet is folded so that the first and second case sections oppose each other, a space is formed to contain the main formation memory medium therein. A flexible polyvinyl chloride sheet which forms a pocket is adhered on the first case section 14. The flexible polyvinyl chloride sheet is located on a surface of the base sheet which opposes a surface at which the space is formed to house the main information memory medium therein. A hole is formed near an opening of the pocket to extend through the flexible polyvinyl chloride sheet.

Abstract: An apparatus for installing a disk having a through hole formed in the center thereof, which comprises a rotatable shaft, a disk support which is fixed to the rotatable shaft and has a supporting surface for supporting the one side of the disk, and a disk holder which is detachably fitted to the rotatable shaft and presses the disk on its other side toward the supporting surface, thereby to cause the disk to be fixed between the disk holder and the disk support. The disk holder includes a holder body which is provided to be fitted onto the rotatable shaft and movable along the rotatable shaft, a pressure assembly which is disposed on the holder body to exert the disk on its other side an elastic pressure against the supporting surface, and a slip preventive mechanism for preventing the holder body from the rotatable shaft by engaging the holder body with the rotatable shaft through the fitting of the holder body onto the rotatable shaft.

Abstract: In a motor unit, a motor shaft is supported by a pair of journal bearings of a herringbone dynamic pressure type. A polygonal mirror is fixed to one end of the motor shaft, and a magnetic thrust bearing is arranged at the other end so that the motor shaft is suspended thereby. The magnetic thrust bearing is formed of ring-shaped first and second permanent magnets. The first permanent magnets are coaxially fixed to the motor shaft and each have one pole on their outer surfaces. The second permanent magnets are fixed to a motor housing, and have their inner surfaces opposed to the outer surfaces of the first permanent magnets. The inner surface of each second permanent magnet has a pole different from that of its corresponding first permanent magnet. The first and second permanent magnets attract one another so that the motor shaft is suspended by attraction.

Abstract: A rotatable mirror having a body with a regular polygon cross section, the faces of the polygon being mirror facets for scanning a laser beam, in combination with a container for storing the mirror. The container cooperates with elements of the mirror for preventing axial or lateral movement of the mirror in the container. Structure on the top surface of the body of the mirror both provides for handling the mirror without touching the facets and interacts with the cover of the container for securing the mirror when therein. A circular groove in the upper surface of the body of the mirror may receive a balance weight for compensating for any eccentricity between the centroid of the mirror and its axis of rotation.

Abstract: A laser scanning apparatus for scanning a stationary document, which comprises a laser beam deflecting means for deflecting a laser beam such that it scans the stationary document in a main scanning direction, a movable optical means provided between the laser beam deflecting means and stationary document and serving to deflect the laser beam such that it scans in an auxiliary scanning direction substantially at right angles to the main scanning direction, and an optical detecting means moved together with the movable optical means and receiving the scattered beam component from said document.

Abstract: A pattern reading device comprises feed mechanism for storing a sheaf of cards carrying patterns and feeding said cards one by one, a conveying mechanism having a plurality of pinch members at regular intervals to pinch the forward edge of each fed card and convey said card to a reading section, and an optical reader provided in said reading section for reading patterns on said cards.