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4738885 Magnetic disk, substrate therefor and process for preparation thereof  
Disclosed is a substrate for a magnetic disk, which comprises a ceramic substrate formed by subjecting a ceramic molded body to hot isostatic pressing in an inert atmosphere and subsequently to...
4737877 Structure to provide optical and capacitive contrast on magnetic recording disk  
A magnetic recording disk is formed on a rigid aluminum substrate coated with a polymeric dielectric layer. A thin film metallic position-indicating track is applied to the upper surface of the...
4737869 Magnetic disk having data area and index servo area and servo system for positioning read/write head on magnetic disk  
A magnetic disk comprises a data area and a single index servo sector area embedded in the data area. The servo sector has three or more servo information pattern sections formed side by side in...
4734810 Magnetic recording medium comprising protrusion on its surface and a plasma treated substrate and recording/reproducing method therefor  
A magnetic recording medium comprising a ferromagnetic metal thin film layer formed on one surface of a flexible non-magnetic substrate and primarily comprising cobalt and oxygen is improved in...
4734796 Technique for preventing unauthorized copying of information recorded on a recording medium and a protected recording medium  
A method for prevention of unauthorized copying from information recording media, such as diskettes, comprising the steps of altering the information storage characteristics of the information...
4729805 Recording medium annealing process  
Stretched surface recording disk (SD) 10 comprises an annular support 12 having raised annular ridges 42 and 28 at its inside and outside diameters 22 and 30 with a base portion 24 in between the...
4725470 Magnetic disk medium  
A magnetic disk medium having a magnetic layer formed on its substrate, is characterized in that in a portion of the substrate where a magnetic head runs is formed a concave groove in which a...
4720329 Apparatus and method for the electrolytic plating of layers onto computer memory hard discs  
An apparatus for electrolytic plating of computer memory discs comprising a plating container, a spindle, a prime mover, an anode, and an electrical transmission system. The plating container...
4717977 High capacity Winchester disk drive  
A digital storage system of the Winchester or hard disk drive type has the hard aluminum disks mounted around the drive motor. To accommodate the difference in thermal coefficients of expansion of...
4716078 Substrate for a magnetic disc and method manufacturing same  
A substrate for magnetic discs, which are to be used as external storage in data processors, is formed from glass-like carbon materials by themselves or contained in a thermosetting resin matrix....
4711115 Method for forming memory discs by forging  
A flat, smooth material, e.g., metal sheet, suitable for use as a disc substrate for applying a recording media thereto for data storage devices, and a method of making same, are disclosed. The...
4707756 Perpendicular magnetic recording medium  
Disclosed is a perpendicular magnetic recording medium wherein an underlayer made of a material containing Si and/or Ge as its principal ingredient is deposited on a substrate, and a perpendicular...
4704650 Oriented sheet supports in a recording disc  
A recording disc in which two recording sheets are bonded to bonding rings at the inner and outer periphery on both sides of a circular substrate with a recess between the recording portion of the...
4704181 Apparatus for fabricating computer disks  
The disk is aligned by means of a centering device that passes through the disk center hole and possesses a recessed region in its tip which mates with the convex center region of the hub. The hub...
4704179 Process for producing magnetic discs  
A process for producing a magnetic disc comprises (1) attaching a flexible disc having a magnetic layer coated thereon to at least one side of a base plate wherein a gap is formed between the back...
4701881 Magneto-optical recording medium  
A magneto-optical recording medium is disclosed in which a magnetic thin film recording layer is formed by a magnetic material having a Curie temperature or magnetic compensation temperature as low...
4698716 Support for magnetic recording disk and its production process  
The support for a magnetic recording disc according to the invention comprises a metal disk covered by an organic coating and, on the latter, a thin, hard coating of a material based on hydrous...
4698715 Magnetic recording disk having center core secured by a base-less double-sided adhesive tape  
A magnetic recording disk cartridge comprises a cartridge casing and a magnetic recording disk accommodated therein for rotation. The magnetic recording disk consists of an annular magnetic...
4698251 Magnetic recording medium and method of producing the same  
A magnetic disk or like magnetic recording medium having a magnetic layer provided on a non-magnetic substrate by dry-process or wet-process plating means and allowing a head to write and read data...
4695512 Magnetic head for perpendicular magnetic recording  
A magnetic head for perpendicular magnetic recording includes a pair of substrates consituted by a non-magnetic material and having their opposing surfaces respectively formed with heat-resistant...
4694370 Magnetic disk cartridge  
A magnetic disk cartridge containing a floppy magnetic disk is provided with center core which has a groove where the vertical part of the core meets the flange upon which the disk is fastened by a...
4694358 Magneto-optic recording structure and method  
A magnetic magneto-optic recording structure and method in which a magneto-optic active layer is positioned within the fringing magnetic field of a magnetic recording medium, the structure...
4692831 Disc cartridge having positive isolation means when in storage  
An improved disc cartridge (1) is disclosed, which comprises a case assembly (4) and an information recording disc (5) flatly rotatably housed in the case assembly. A disc holding mechanism is...
4689260 Abrasion-resistant magnetic recording disk  
A magnetic recording disk comprises a magnetic layer consisting of a binder and magnetic particles, a silicon substrate and abrasion-resistant material formed on the silicon substrate. The...
4688130 Perpendicular magnetic recording medium and production process thereof  
A perpendicular magnetic recording medium is formed of a substrate having 5×10 5 -5×10 9 fine projections per mm 2 on the surface thereof, said projections having heights in the range of...
4687536 Apparatus for centering and attaching a reinforcing ring to a floppy disk  
Apparatus for positioning and attaching a reinforcing ring in coaxial relationship to a floppy disk, includes a force translating mechanism mounted for movement to and from a resiliently mounted...
4686592 Disk drive assembly  
An improved disk drive device including a disk of recording media and having a central aperture, which disk is supported at its periphery by a cylindrical housing. A spindle motor is positioned at...
4678722 Record member with metallic antifriction overcoat  
A magnetic recording member with a thin metallic antifriction protection overcoat formed over a magnetic layer. The overcoat is soft ductile and low stress and includes a metal selected from the...
4675239 Perpendicular magnetization film  
A perpendicular magnetization amorphous thin film of an alloy of samarium, cobalt and bismuth having an easy magnetizing axis perpendicular to a plane of substrate, and the preparation thereof....
4672488 Spindle hub-disc interface  
To overcome problems of precise permanent location of aluminum Winchester discs relative to their steel drive spindle during temperature variations, in one form of the invention a plastic washer is...
4671995 Magnetic recording medium comprising an undercoating made of a mixture of thermosetting polyurethane and polyester resins  
A magnetic recording medium which comprises a non-magnetic support, and a magnetic layer formed on the support through an undercoat layer is described. The undercoat layer is made of a cured...
4667257 Disk drive and centering mechanism for microfloppy disk drive  
An improved disk drive and centering mechanism for attachment to the spindle of a microfloppy drive, including a first circular segmented plate attached to a second circular segmented plate by four...
4660119 Flexible magnetic disk sheet  
A flexible magnetic disk sheet having a central circular hole is described, through which an apparatus for reading and writing is engaged, and enclosed in an jacket having a larger central circular...
4659633 Magnetic recording medium  
A magnetic recording medium having good durability comprising a substrate and one or two magnetic layers at least a surface of which contains at least one compound selected from the group...
4659627 Magnetic recording medium with lubricant  
Magnetic recording media having a coating containing harsh pigment like CrO 2 particles and adapted for frequent contact with a head, with good durability, abrasivity, etc., accommodated by using...
4654276 Magnetic recording medium with an underlayer and a cobalt-based magnetic layer  
An improved cobalt-platinum (CoPt) thin film metal alloy media for horizontal magnetic recording has a coercivity substantially greater than prior CoPt thin film metal alloy media. A tungsten...
4652499 Magnetic recording medium with a chromium alloy underlayer and a cobalt-based magnetic layer  
An improved cobalt-platinum (CoPt) thin film metal alloy media for horizontal magnetic recording has a squareness greater than prior CoPt thin film metal alloy media. An underlayer of a...
4652496 Magnetic recording medium  
Disclosed is a magnetic recording medium which comprises a support, a magnetic recording layer and optionally a back-coating layer, at least of said magnetic recording layer and said back-coating...
4650708 Magnetic recording material and a method for producing the same  
In production of a magnetic recording material which accumulates information in magnetic substance packed in micro pores extending in the thickness direction of an anodic oxide surface layer formed...
4647507 Magnetic recording material  
A magnetic recording medium wherein a thin layer comprising an organic compound having at least one carboxyl or mercapto group, at least one fluoroalkyl group having 3 or more carbon atoms and at...
4647506 Flexible, self-cross-linking binders  
Flexible, self-cross-linking binders, useful for, e.g., paints and magnetic media composites, are prepared from hydroxyl-containing thermoplastic polymers reacted with condensates of diisocyanates...
4647473 Method for forming protective layer on a flexible magnetic disc sheet  
A method for forming protective layer on a surface portion surrounding the edge of a central aperture of a flexible magnetic disc sheet is described, comprising providing a radiation polymerizable...
4646179 Flexible magnetic disc, positioning apparatus and method permitting improved head contact  
A flexible magnetic disc for use in combination with a magnetic head assembly which includes a regulator plate and performs magnetic recording or playback by protruding a magnetic head beyond a...
4645722 Photo-thermo-magnetic recording medium and method of preparing same  
A recording medium suitable for use in a photo-thermo-magnetic memory of high density recording, including a substrate; a first magnetic layer, such as an amorphous TbFe film, which has a large...
4643949 Magnetic recording tape  
Magnetic recording tape comprising a flexible substrate with magnetic particles secured to the substrate by means of a binder comprising a reaction product of a diisocyanate with a blend of a chain...
4643947 Magnetic recording material  
A magnetic recording material which comprises a non-magnetic substrate, and a magnetic layer formed on at least one surface of the substrate. The magnetic layer is made of a uniform dispersion of a...
4643934 Magnetic recording medium  
In a magnetic recording medium having a magnetic recording coat formed on one side of a base and a back coat on the other side, the back coat consists of a dispersion in a binder of an inorgainc...
4642709 Twin track vertical magnetic recording servo control method  
The invention discloses a twin track servoing method and apparatus useful for vertical magnetic media recordings. Vertical magnetic media are those in which the magnetic vector in the medium is...
4640863 Magnetic recording media  
A magnetic recording medium comprising a flexible support and a magnetic layer formed on the flexible support. The flexible support is made of a resin composition which comprises thermoplastic...
4639815 Magnetic recording medium with chromiumiron protective layer  
A magnetic recording medium comprising a non-magnetic support, a thin magnetic metal film on the support, and a protective layer on the thin magnetic film, the protective layer containing chromium...