Abstract: The present invention is to provide 4-fluoro-3-oxocarboxylates represented by the following formula (1): wherein R1 represents an alkyl group or an aryl group; R2 and R3 each represent a hydrogen atom or an alkyl group; and R4 represents an alkyl group, and a process for preparing a 4-fluoro-3-oxocarboxylate represented by the above formula (1), which comprises allowing a 2-fluorocarboxylate represented by the following formula (2): wherein R1 and R2 have the same meanings as defined above; and R5 represents an alkyl group, to react with a carboxylate represented by the following formula (3): wherein R3 and R4 have the same meanings as defined above, in the presence of a base.

Abstract: A disk drive apparatus in which a disk is held on a tray 5 and is then loaded. The disk drive apparatus includes an arrangement in which a wall portion 15 is provided at the front portion of the tray 5 for preventing an invasion of dust and the like.

Abstract: A disc cassette comprises a case in which a recording disc is rotatably received. The case has an opening through which the disc is exposed. A bridge defined by the case extends across a mouth portion of the opening. A slide bar is arranged beside the bridge in a manner to move axially therealong. A shutter is connected to the slide bar to move therewith. The shutter selectively opens and closes the opening in accordance with axial movement of the slide bar. The slide bar has a base portion which comes beside the bridge when the shutter takes the open position, and the base portion is formed with a recess which faces in a direction away from the center of the disc recording medium.

Abstract: The present invention is to provide a novel 6-(1-fluoroalkyl)-4-pyrimidone represented by the following formula (1): wherein R1 represents an alkyl group; R2 represents a hydrogen atom or an alkyl group; and R3 represents a hydrogen atom, an alkyl group or a chlorine atom, which is important for a synthetic intermediate for aminopyrimidine derivatives which are useful as acaricides, fungicides or nematocides, and processes for producing the same.

Abstract: An optical pickup device capable of irradiating laser beams on a signal recording surface of magneto-optical disk is provided. The optical pickup device so provided includes a separate optical system whose moveable portion is reduced in weight in order to cope with high-speed access.

Abstract: A recording and reproducing apparatus having a holder for holding an inserted cartridge with a recording medium stored therein in which a recording medium is loaded or unloaded at the recording and reproducing position for recording and/or reproducing information as the holder is elevated or lowered, including a driver on which the recording medium rests at the recording and reproducing position and driving the recording medium for recording and/or reproduction and an elevator having an elevating and lowering operation cam formed on its side portion and elevating or lowering the holder when it is slid in parallel to the direction in which the cartridge is inserted.

Abstract: An optical pickup device capable of irradiating laser beams on a signal recording surface of a magneto-optical disk is provided. The optical pickup device so provided includes a separate optical system whose moveable portion is reduced in weight in order to cope with high-speed access.

Abstract: A recording and reproducing apparatus having a holder for holding an inserted cartridge with a recording medium stored therein in which a recording medium is loaded or unloaded at the recording and reproducing position for recording and/or reproducing information as the holder is elevated or lowered, including a drive portion on which the recording medium rests at the recording and reproducing position and driving the recording medium for recording and/or reproduction and an elevating portion having an elevating and lowering operation cam formed on its side portion and elevating or lowering the holder when it is slid in parallel to the direction in which the cartridge is inserted.

Abstract: A disk drive apparatus that provides for a positional relationship between an optical disk and an optical pickup device to be set in a predetermined initial state before an information storage and reproducing operation. The disk drive apparatus includes a disk table that is rotated by a spindle motor and onto which an optical disk is loaded and an optical pickup device for recording and reproducing information on and from the optical disk. The disk drive apparatus further includes a skew sensor for detecting the inclination of a light beam's optical axis relative to the optical disk, a skew control mechanism for adjusting that inclination, a reference portion detected by the skew sensor, and control means. The control means sets the skew control mechanism in its predetermined initial state based on an output from the skew sensor obtained from detection of the reference portion.

Abstract: A disk cartridge is provided for storing a recording disk in a space formed by fastening an upper half and a lower half. At least either the upper half or the lower half has a pair of groove portions defined on its right and left side surfaces from the front end to the central portion direction so as to oppose a mis-insertion preventing protrusion portion formed on a disk drive. Engagement concave portions which are engaged and held by the holding member disposed within the disk drive when the disk cartridge is loaded into the disk drive are provided on the inner surfaces of the groove portions.

Abstract: An optical pickup device capable of irradiating laser beams on a signal recording surface of a magneto-optical disk is provided. The optical pickup device so provided includes a separate optical system whose moveable portion is reduced in weight in order to cope with high-speed access.

Abstract: The present invention comprises an improved organic composite-plated steel plate which is obtained by applying a thermosetting resin to a chromate-coated alloy-plated steel plate and curing this, wherein, various aqueous resin compositions having the form of basic coating film formation components, such as, for example, aqueous vinyl modified epoxy ester resins, or aqueous vinyl modified epoxy ester resin / blocked isocyanate compound-types, or aqueous vinyl modified epoxy ester resin / blocked isocyanate compounds / colloidal silica-types, are used as the thermosetting resin described above.

Abstract: An optical disc driving device employing an optical disc as a recording medium. The device includes a skew control mechanism for controlling relative tilt between an optical disc and an objective lens for selectively recording and/or reproducing data on or from a first optical disc having a standard recoding density and a second optical disc having a high recording density. The relative tilt between the second optical disc and the objective lens is controlled by the skew control mechanism only when the second optical disc is loaded and data is recorded and/or reproduced on or from the second optical disc.

Abstract: A disk cartridge including a housing which rotatably accommodates therein a disk, such as a magneto-optic disk, which has a main recording surface and a protective surface. The housing is formed of upper and lower halves with the upper half having a first opening capable of exposing the protective layer to a magnetic-field application head of the disk unit and the lower half having a second opening capable of exposing the main recording surface to an objective lens assembly of the disk unit when the disk cartridge is inserted into the disk unit. The first and second openings are provided at a cartridge insertion end of the cartridge and are each of a defined width measured in the lateral direction of the cartridge and are designed such that the defined width of one of the first and second openings is smaller than the defined width of the other of the first and second openings.

Abstract: A disc drive unit for driving a disc recording medium such as a magneto-optical disc accommodated in a disc cassette, comprises a chassis, a cassette holder having a pair of wall sections and moveable up and down between upper and lower positions with respect to the chassis, and the disc cassette being injectable into and ejectable from the cassette holder, a disc rotating mechanism being moveable up and down between upper and lower positions with respect to the chassis and chucked with the disc recording medium for rotatively driving the disc recording medium, height-level positioning members provided at the chassis, so that at least their upper ends are located at a higher level than the lower wall section of the cassette holder, when the cassette holder is held at its lower position, and a loading motor unit for shifting the cassette holder from its upper position to its lower position and for shifting the disc rotating mechanism from its lower position to its upper position, during loading of the disc cas

Abstract: A disc drive unit for a magneto-optical disc accommodated in a disc cassette, comprises a magnetic head for applying a magnetic field to the magneto-optical disc, a magnetic head moving mechanism for moving the magnetic head between a loading and unloading position, an eject mechanism for ejecting the disc cassette, a reversible motor, and a transmission device for transmitting a rotational force of the reversible motor to the magnetic-head moving mechanism by rotation of the motor in its one rotational direction and for transmitting the rotational force of the reversible motor to the eject mechanism in its other rotational direction whereby a controller is provided for controlling the reversible motor so that a rotational speed of the motor in the other rotational direction used for the eject mechanism is faster that the rotational speed of the reversible motor in the one rotational direction used for the magnetic-head moving mechanism in order to ensure the quick ejection of the disc cassette.

Abstract: Disclosed herein is a disk drive device comprising a chassis; a spindle motor vertically movably mounted on the chassis, for rotatively driving a disk-shaped recording medium; a cam adapted to contact a pin projecting from the spindle motor, for vertically driving the spindle motor through the pin; a loading motor mounted on the chassis, for rotatively driving the cam; a block fixed to the chassis, for restricting an upper limit of a vertical stroke of the spindle motor: and a spring for biasing the spindle motor against the block. Accordingly, the spindle motor can be stably positioned in a loaded condition of the disk-shaped recording medium, and the construction can be simplified with no need of high accuracy of the cam.

Abstract: A disc recording and/or reproducing apparatus including a signal recording/reproducing section for recording and/or reproducing information signals on a disc 64 mm in diameter housed in a cartridge main body to form a disc cartridge, a loading mechanism for loading or unloading the disc cartridge on or from the signal recording/reproducing section and a control circuit controlling the recording/reproducing operation of the recording/reproducing section. The disc has a signal recording part divided into plural signal recording zones of substantially equal line recording density across the inner and the outer peripheries of the disc. The signal recording/reproducing section, the loading mechanism and the control circuit are housed in a casing which is 70 mm or less in width, 100 mm or less in length and 24.5 mm or less in height and which is provided with a disc inserting opening. The apparatus may be reduced in size without decreasing the recording capacity.

Abstract: The present invention comprises an improved organic composite-plated steel plate which is obtained by applying a thermosetting resin to a chromate-coated alloy-plated steel plate and curing this, wherein, various aqueous resin compositions having the form of basic coating film formation components, such as, for example, aqueous vinyl modified epoxy ester resins, or aqueous vinyl modified epoxy ester resin/blocked isocyanate compound-types, or aqueous vinyl modified epoxy ester resin/blocked isocyanate compounds/colloidal silica-types, are used as the thermosetting resin described above.

Abstract: A disc recording and/or reproducing apparatus including a signal recording/reproducing section for recording and/or reproducing information signals on a disc 86 mm in diameter housed in a cartridge main body to form a disc cartridge, a loading mechanism for loading or unloading the disc cartridge on or from the signal recording/reproducing section and a control circuit controlling the recording/reproducing operation of the recording/reproducing section. The disc has a signal recording part divided into plural signal recording zones of substantially equal line recording density across the inner and the outer peripheries of the disc. The signal recording/reproducing section, the loading mechanism and the control circuit are housed in a casing which is 101.6 mm or less in width, 150 mm or less in length and 25.4 mm or less in height and which is provided with a disc inserting opening. The apparatus may be reduced in size without decreasing the recording capacity.