Abstract: Minute and uniform line marks can be formed on the surface of a glass substrate for a magnetic disk by pressing a woven cloth tape comprising plastic fibers preferably by a rubber roller with hardness greater than 60 and causing it to run thereover while supplying a suspension containing abrading particles and a solution which contains hydroxyl groups such as a KOH solution.

Abstract: A polishing cloth has a surface layer stacked over a base material. The surface layer is made of a foamed layer and a non-foamed layer, the foamed layer including air bubble cells and the non-foamed layer having an externally exposed surface where linear cuts are formed. These linear cuts reach the air bubble cells such that the air bubble cells communicate with the exterior through the linear cuts. These linear cuts are controlled to be 10 &mgr;m or less in length. Such a polishing cloth is produced by applying a foamable coating material such as a foamable resin over a surface of the base material, foaming the foamable coating material to form the surface layer, and forming the linear cuts through the non-foamed layer.

Abstract: Polishing slurry for texturing the surface of a magnetic hard disk substrate has abrading particles with diameters in the range of 1-10 nm dispersed in a dispersant such as water and a water-based aqueous solution. The abrading particles may be monocrystalline diamond particles, polycrystalline diamond particles or cluster particles with monocrystalline and polycrystalline diamond particles. A method of texturing a surface of a magnetic hard disk substrate includes the steps of rotating the magnetic hard disk substrate, supplying polishing slurry of this invention on the surface of the substrate, and pressing a polishing tape on the substrate surface and running the polishing tape.

Abstract: A polishing tape makes use of a foamed material such as polyurethane foam attached to a plastic backing material. The foamed material is elastic and some of its gas holes formed inside but near one of its surfaces are exposed externally. Because of its elastic nature, it can be deformed even if there are abnormally large abrading particles contained in a liquid slurry and such abrading particles do not become embedded in the target surface being textured. These externally exposed gas holes can also serve to absorb the debris generated by the texturing and to protect the target surface from being scratched thereby. Such a tape is used for a texturing process while dropping a liquid slurry containing abrading particles and rotating the disk substrate and pressing the tape against the target surface.

Abstract: A polishing cloth has a base material of a woven cloth formed by weaving in woven bundles of plastic fibers and its surface layer is formed by portions of these woven bundles which are cut and raised from a surface. When such a polishing cloth is used for texturing a target surface of a disk substrate, the target surface is rubbed by such a cloth while a liquid slurry containing free abrasive particles are supplied to the surface.

Abstract: A foamed polishing sheet for use in a free particle polishing method using abrading particles with average particle diameter less than 0.1 &mgr;m is produced by applying a foaming paint of a foaming resin on a surface of a form-providing film such as a plastic film, foaming the foaming paint by a wet foaming method to form a foamed sheet on the surface of the form-providing film, and peeling off the foamed sheet from the form-providing film so as to form a polishing surface on the foamed sheet having the same shape as the surface of the form-providing film.

Abstract: An agent used for texturing a surface of a substrate for a magnetic disk includes an aqueous solution containing a glycol compound serving as surfactant in an amount of about 1-25 weight % and agglomerated polycrystalline diamond particles with average diameter of 0.01-2 &mgr;m in an amount of 0.001-3 weight % formed with very small polycrystalline diamond particles with average diameter of 1-20 nm. When the substrate surface is textured, the substrate is rotated, the agent is supplied to the target surface to be textured and a polishing tape is pressed and run against it. A substrate thus processed has a surface with very fine and uniform textured lines without any abnormal protrusions.

Abstract: A polishing tape makes use of a foamed material such as polyurethane foam attached to a plastic backing material. The foamed material is elastic and some of its gas holes formed inside but near one of its surfaces are exposed externally. Because of its elastic nature, it can be deformed even if there are abnormally large abrading particles contained in a liquid slurry and such abrading particles do not become embedded in the target surface being textured. These externally exposed gas holes can also serve to absorb the debris generated by the texturing and to protect the target surface from being scratched thereby. Such a tape is used for a texturing process while dropping a liquid slurry containing abrading particles and rotating the disk substrate and pressing the tape against the target surface.

Abstract: A glass substrate for a magnetic disk has one or both of its surfaces processed by applying a suspension of a specified kind onto the surface to be processed while the substrate is rotated and a polishing tape is pressed and run against the surface to be processed. The suspension includes abrasive particles with average diameter selected according to the purpose of the processing and an aqueous solution containing a reacting liquid capable of causing a solid phase reaction at contact boundary surfaces between the surface of the glass substrate and these abrasive particles. The polishing tape is removed from the glass substrate when the polishing is over but while the tape is still running and the glass substrate is rotating. The supplying of the suspension is thereafter stopped and a washing liquid such as water is applied to the polished surface or surfaces while the substrate is still rotating. Both surfaces of a glass substrate may be polished at the same time.

Abstract: A polishing tape makes use of a foamed material such as polyurethane foam attached to a plastic backing material. The foamed material is elastic and some of its gas holes formed inside but near one of its surfaces are exposed externally. Because of its elastic nature, it can be deformed even if there are abnormally large abrading particles contained in a liquid slurry and such abrading particles do not become embedded in the target surface being textured. These externally exposed gas holes can also serve to absorb the debris generated by the texturing and to protect the target surface from being scratched thereby. Such a tape is used for a texturing process while dropping a liquid slurry containing abrading particles and rotating the disk substrate and pressing the tape against the target surface.

Abstract: A polishing cloth has a base material of a woven cloth formed by weaving in woven bundles of plastic fibers and its surface layer is formed by portions of these woven bundles which are cut and raised from a surface. Such a polishing cloth can be produced by preparing a woven cloth as its base material by weaving in woven bundles of plastic fibers, cutting portions of these woven bundles over a surface of the woven cloth, and forming a surface layer by raising the cut portions of the woven bundles from a surface. When such a polishing cloth is used for texturing a target surface of a disk substrate, the target surface is rubbed by such a cloth while a liquid slurry containing free abrasive particles are supplied to the surface.

Abstract: A polishing cloth having a base material of a woven cloth formed by weaving in woven bundles of plastic fibers and its surface layer formed by portions of these woven bundles which are cut and raised from a surface is produced by preparing a woven cloth as its base material by weaving in woven bundles of plastic fibers, cutting portions of these woven bundles over a surface of the woven cloth, and forming a surface layer by raising the cut portions of the woven bundles from a surface.

Abstract: An electrolytic liquid slurry containing pure water, abrading particles and nitric acid, boric acid, alkanol amine, sodium sulfite, sodium chloride, ammonium chloride, sodium phosphate, potassium phosphate, sodium silicate, aluminum phosphate, ammonium phosphate, diethanolamide borate, amine borate, sodium metaborate, propylene glycol or their liquid mixture is supplied to the surface of a magnetic hard disk substrate or the surface of a tape. The tape is pressed against the surface of the disk substrate and a voltage difference is applied between an electrode disposed in contact with the electrolytic liquid slurry and the disk substrate which serves as another electrode. Since texturing and electrolytic processes are thus carried out simultaneously, the stock removal can be increased and the throughput can be improved.

Abstract: Polishing compositions with phosphoric ester added to a suspension containing abrasive particles can have an improved ability to have the abrasive particles dispersed again after they are left for an extended period of time such that the particles may have condensed into aggregates. Those with abrasive particles such as diamond powder dispersed in an aqueous solution containing a glycol compound, metallic salt of a higher aliphatic acid and phosphoric ester have an improved polishing ability.

Abstract: An information recording/reproducing apparatus that is an magneto-optical disk drive apparatus includes a disk controller that is connected to a SCSI controller and controls data transfer from/to a disk rotated by a spindle motor a cache memory temporarily storing data read from and written to the disk, a CPU controlling operation of respective blocks of the apparatus, a program storage that has an analyzing block for analyzing a file management area in the disk, and stores that operational programs for the CPU, and a read/write controller controlling record/reproduction of data to/from the disk. In this construction, since a part of D file management area in the disk is cached all the time at the time of read, data through a plurality of read from operations the boot sector, FAT1, and root directory are sent respectively from the cache memory without accessing the disk.

Abstract: A liquid slurry containing spherical abrading particles of polyhedral monocrystalline alumina is supplied onto the target surface of a magnetic hard disk substrate to be textured while a polishing tape is pressed onto the target surface and the disk substrate is concurrently rotated. Because the contacting surfaces of these particles are spherical and have no sharp edges, they do not scratch the target surface or create grooves which are undesirably too deep.

Abstract: A semiconductor laser driving apparatus for use in an information recording/reproducing apparatus that records and reproduces information by illuminating a medium with a laser beam.

Abstract: A tracking servo system for controlling the positional difference between a recording track of an optical disk and a light beam emitted on the track, in which the amount of offset control applied to an offset adjusting amplifier provided in the servo loop is varied and the center value of the positive and negative peak values of a track error signal obtained at that time is computed. Then, the relation between the amount of offset control and the center value of the peak values of the track error signal is determined and the amount of offset control corresponding to the desired center value of the peak values of the track error signal is obtained on the basis of the determined relation. Further, a laser beam emission power adjusting system used for recording and/or reproducing in an optical disk apparatus is disclosed, in which the laser beam emission adjusting output is varied and the amount of beam emission power obtained at that time is detected.

Abstract: An information recording/reproducing apparatus has a controller for setting the apparatus in a ready state in which at least one of information reproduction, information recording and information erasure can be effected after a recording medium is loaded, in the case where an external request has been detected within a predetermined time period. The controller sets the apparatus in a non-ready state after a recording medium is loaded, in the case where an external request has not been detected within a predetermined time period.

Abstract: A medium replaceable recording and reproducing apparatus comprises a medium insertion detecting unit for detecting that at least a part of a recording medium is inserted into a recording and reproducing apparatus for the recording medium, a drive loading detecting unit for detecting that the recording medium is loaded onto medium driver for driving the recording medium, and a medium discriminating unit for monitoring an output of the medium insertion detecting unit, and discriminating whether a recording medium loaded onto the medium driver is a new one or the same reloaded one as loaded just before.