Abstract: An optical disk for use in an optical memory device having guide grooves and pits on one surface thereof, wherein the depth of the guide grooves is different from that of the pits and the distance from the bottom face of each of the guide grooves to the other surface of the optical disk opposite to the one surface of the optical disk on which the guide grooves and pits are disposed is the same as the distance from the bottom face of each of the pits to the other surface of the optical disk opposite to the one surface of the optical disk on which the guide grooves and pits are disposed, and a method for the production of optical memory master plates that are used for the production of the above-mentioned optical disk.

Abstract: An optical disk for use in an optical memory device having guide grooves and pits on one surface thereof, wherein the depth of the guide grooves is different from that of the pits and the distance from the bottom face of each of the guide grooves to the other surface of the optical disk opposite to the one surface of the optical disk on which the guide grooves and pits are disposed is the same as the distance from the bottom face of each of the pits to the other surface of the optical disk opposite to the one surface of the optical disk on which the guide grooves and pits are disposed, and a method for the production of optical memory master plates that are used for the production of the above-mentioned optical disk.

Abstract: A feeding apparatus has a large turntable mounted rotatably on a tray and two paper cassettes installed on the turntable. The paper cassette are movable in a radial direction of rotation of the turntable. Carriage driving mechanisms for moving the paper cassettes are controlled to move the respective paper cassettes to positions closest to the axis of rotation of the turntable when rotating the turntable so that the space occupied by the paper cassettes is minimized. A 180-degree rotation mechanism for rotating the turntable is controlled to rotate the turntable after the respective paper cassettes are moved to the positions closest to the axis of rotation of the turntable, for interchanging the paper cassette on a feeding side and the paper cassette on a non-feeding side. This enables a reduction in the size of the apparatus, irrespective of the sizes and positions of the paper cassettes on the feeding side and non-feeding side.

Abstract: A magneto-optical disk comprising a substrate whereon a recording medium is formed, and a depression is formed on the substrate on the inside of the recording medium of the substrate. A center hub is installed on the depression such that the center hub is substantially level with a protective resin layer covering the recording medium. On the center hub, a flying head performs CSS (Contact Start and Stop). This configuration of the disk eliminates the occurrence of dust due to the abrasion and head crash, and achieves stable CSS. A method of manufacturing the magneto-optical disk, wherein the protective resin layer is formed after installing the center hub on the depression. In this method, since a space is not produced between the center hub and the protective resin layer, the stable flying characteristics is obtained. And a magneto-optical disk whereon small physical bumps and pits are formed on the substrate on the inside of the recording medium, which prevents the flying head from sticking to the disk.

Abstract: A large turntable is mounted rotatably on a tray, and two paper cassettes are rotatably installed on the turntable. The turntable is rotated by a 180-degree rotating mechanism and a small angle rotating mechanism, while the paper cassette is rotated by a cassette rotating mechanism. The 180-degree rotating mechanism interchanges the paper cassette on a feeding side and the paper cassette on a non-feeding side by rotating the turntable. The small angle rotating mechanism aligns the center of paper stored in the paper cassette on the feeding side with a feeding center line by rotating the turntable. The cassette rotating mechanism positions the leading edge of the paper in the paper cassette on the feeding side at right angles to a feeding direction by rotating the paper cassette. Since the 180-degree rotating mechanism and the small angle rotating mechanism are installed in positions on the tray outside of the turning space of the turntable, an apparatus of a reduced height and size is achieved.

Abstract: A carriage driving mechanism moves a paper cassette forward and backward along a feeding direction. A cassette rotating mechanism rotates the paper cassette. A single carriage driving mechanism and a single cassette rotating mechanism are provided for each paper cassette and installed on a level between a cassette circular plate and a large turntable. The carriage driving mechanism includes a driving system constituted by a pulse motor, a series of gears, a pulley, a carriage, a wire wound around the pulley, and guide bars. The cassette rotating mechanism includes a pulse motor and a series of gears. The driving system of the carriage driving mechanism and the cassette rotating mechanism are mounted on the bottom surface of the carriage so as to be level, and move along with the carriage. This configuration enables a reduction in the height and size of a rotatable cassette-type feeding apparatus and an increase in copying functions.

Abstract: A rotatable cassette-type paper feeding apparatus includes a tray, a turning member mounted rotatably on the tray. A first rotating device is used for rotating the turning member, a plurality of paper cassettes installed rotatably on the turning member. A second rotating device is used for rotating the paper cassette in a paper feeding side, and a controller which controls the first rotating device to interchange the paper cassettes in the paper feeding side and in the non-paper-feeding side and which controls the second rotating device to switch the position of the paper cassette in the paper feeding side between sideways and lengthways. This structure achieves a compact rotatable cassette-type paper feeding apparatus capable of storing sheets of paper of various sizes and of feeding the paper sheets both sideways and lengthways by switching their positions.