Erase Patents (Class 360/118)
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Patent number: 11908498Abstract: A first straight line region and a second straight line region of the straight line region pair are inclined in opposite directions with respect to a first imaginary straight line. The first straight line region has a steeper inclined angle with respect to the first imaginary straight line than the second straight line region. Positions of both ends of the first straight line region and positions of both ends of the second straight line region are aligned in a direction corresponding to a width direction of a magnetic tape. A plurality of gap patterns deviate from each other by a predetermined interval in a direction corresponding to a longitudinal direction of the magnetic tape, between the gap patterns adjacent to each other along the direction corresponding to the width direction of the magnetic tape. A substrate is inclined with respect to the first imaginary straight line.Type: GrantFiled: September 22, 2022Date of Patent: February 20, 2024Assignee: FUJIFILM CORPORATIONInventors: Toru Nakao, Tetsuya Kaneko, Yoichi Akano
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Patent number: 11188270Abstract: Provided are a computer program product, system, and method in accordance with one embodiment of the present description, in which selected memory resources targeted for secure data cleaning. For example, memory resources which may be targeted for secure data cleaning may include a specific volume (or portion of a volume) of data storage which has been selected for secure erasure of any residual data which may remain on the targeted storage volume before the volume is released for use by others. Other examples of memory resources which may be targeted for secure data cleaning in accordance with the present description may include one or more buffers located in switches or other storage area network components which provide data paths between hosts and storage controllers or storage control units. Other aspects of targeted secure data overwriting in accordance with the present description are described.Type: GrantFiled: May 25, 2016Date of Patent: November 30, 2021Assignee: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Matthew G. Borlick, Kurt A. Lovrien, Karl A. Nielsen
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Patent number: 10902882Abstract: An apparatus, according to one approach, includes an inner array of data transducers on a module, the data transducers of the inner array being aligned along a common axis that extends between distal ends of the module. Two outer arrays of data transducers are positioned on the module to sandwich the inner array therebetween. Inner servo readers are positioned between the inner array and the outer arrays. Outer servo readers are positioned toward outer ends of the outer arrays. A method, according to one approach, includes passing a magnetic recording tape having a plurality of data bands over a module as described above. Data on two of the data bands is simultaneously transduced (read and/or written) using the data transducers of the inner and outer arrays. Thus, the bandwidth of the data operation can be increased, e.g., effectively doubled.Type: GrantFiled: August 27, 2019Date of Patent: January 26, 2021Assignee: International Business Machines CorporationInventor: Robert G. Biskeborn
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Patent number: 10475472Abstract: The present invention provides a magnetic head for erasing data on a magnetic tape, the magnetic head comprising a body having an elongate magnet mounted thereon, and a plurality of magnetisable portions in magnetisable communication with the magnet, the plurality of magnetisable portions being aligned with the elongate magnet and forming at least a portion of a substantially planar external surface of the magnetic head. The present invention further provides a method and system for erasing data on a magnetic tape using said magnetic head.Type: GrantFiled: June 21, 2017Date of Patent: November 12, 2019Assignee: Insurgo Media Services LtdInventor: Roy Spiller
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Publication number: 20140376128Abstract: The present disclosure relates generally to writing and reading data from a magnetic tape storage media and, more particularly, to a secure erasure system for the eradication of the data contained in the data tracks of a tape media such that substantially all of the data can be erased while leaving the servo bands substantially unaltered or within specification. A data tape cartridge erased with such a system can then be reused in a secure data storage environment with complete confidence that any data from a previous usage is not subject to discovery.Type: ApplicationFiled: July 1, 2014Publication date: December 25, 2014Inventors: Gregory Lawrence Wagner, Matthew P. Dugas
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Patent number: 8760802Abstract: A system comprises a magnetic medium with a first magnetic gap adjacent a first side and a second magnetic gap adjacent a second side, opposite the first magnetic gap. The first magnetic gap generates first longitudinal and perpendicular field components. The second magnetic gap generates second longitudinal and perpendicular field components. The first and second longitudinal field components are substantially aligned along a recording layer of the magnetic medium, and the first and second perpendicular field components are substantially opposed across the recording layer of the magnetic medium.Type: GrantFiled: March 12, 2013Date of Patent: June 24, 2014Assignee: Imation Corp.Inventors: Stephen J. Rothermel, Douglas W. Johnson
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Patent number: 8369045Abstract: A hard disk drive includes a chassis which supports a “sealed” housing containing a data storage magnetic disk, and read/write heads and actuator. The housing also contains an erasure device which generates a magnetic or other field or emanation for erasing the disk, so that the erasing field or emanation need not penetrate the sealed housing to effectuate erasure. A backup power supply provides power to the erasing device so that erasure can occur even in the absence of external power. A bus- or network-actuated arrangement couples power to the erasure device so that many hard drives may be simultaneously erased.Type: GrantFiled: June 29, 2012Date of Patent: February 5, 2013Assignee: Lockheed Martin CorporationInventors: Vladimir Gershman, Ronald Dean, Bernard McGarth
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Patent number: 8363354Abstract: A bulk eraser for erasing recorded information on a magnetic-recording disk. The bulk eraser includes a plurality of magnets and a structure magnetically coupled with the plurality of magnets to produce magnetic-flux density in a gap. The gap has a first portion, a second portion and a third portion. Two magnets are disposed with opposing polarity across the first portion of the gap. The plurality of magnets and the structure are configured to produce a magnetic-flux density in the second portion of the gap sufficient to erase recorded information from a portion of at least one magnetic-recording disk in a disk-stack of the hard-disk drive when the hard-disk drive is inserted into the second portion of the gap. The plurality of magnets and the structure are configured to direct the magnetic-flux density in a substantially radial direction of the portion of the magnetic-recording disk.Type: GrantFiled: December 17, 2008Date of Patent: January 29, 2013Assignee: HGST, Netherlands B.V.Inventors: Lidu Huang, Fu-Ying Huang
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Patent number: 8282843Abstract: A method of manufacturing a perpendicular magnetic head having a writing element that writes magnetic information to a recording medium includes forming a main magnetic pole part generating a magnetic field on a substrate; removing at least a part of the substrate and a material existing at a circumference of the main magnetic pole part to expose an entire circumference of the main magnetic pole part at a surface that becomes an opposing medium surface (ABS) opposite to the recording medium; forming a shield gap film that is made of a nonmagnetic material so as to cover the entire circumference of the main magnetic pole part at least at the surface that becomes the ABS; and forming a shield layer so as to cover an entire circumference of the shield gap film at least at the surface that becomes the ABS.Type: GrantFiled: November 10, 2009Date of Patent: October 9, 2012Assignee: TDK CorporationInventors: Tatsuhiro Nojima, Hisayoshi Watanabe, Masachika Hashino
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Patent number: 8213115Abstract: A hard disk drive includes a chassis which supports a “sealed” housing containing a data storage magnetic disk, and read/write heads and actuator. The housing also contains an erasure device which generates a magnetic or other field or emanation for erasing the disk, so that the erasing field or emanation need not penetrate the sealed housing to effectuate erasure. A backup power supply provides power to the erasing device so that erasure can occur even in the absence of external power. A bus- or network-actuated arrangement couples power to the erasure device so that many hard drives may be simultaneously erased.Type: GrantFiled: March 5, 2010Date of Patent: July 3, 2012Assignee: Lockheed Martin CorporationInventors: Vladimir Gershman, Ronald Dean, Bernard McGrath
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Patent number: 7930494Abstract: Techniques are provided for performing multi-pass erase. An erase command is received at a storage area network (SAN) switch in a storage area network. The erase command is associated with a block of data on a target device. A virtual initiator is determined for performing the erase command on the block of data. Multiple bit patterns are generated using a multi-pass erase algorithm. The multiple bit patterns are generated for writing over the block of data on the target device. Repeated writes are performed over the block of data using the bit patterns. The block of data is repeatedly overwritten to remove remanence of the block of data on the target device.Type: GrantFiled: March 23, 2010Date of Patent: April 19, 2011Assignee: Cisco Technology, Inc.Inventors: Muhammad Asim Goheer, Maurilio Cometto, Prashant Billore
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Patent number: 7706102Abstract: A hard disk drive includes a chassis which supports a “sealed” housing containing a data storage magnetic disk, and read/write heads and actuator. The housing also contains an erasure device which generates a magnetic or other field or emanation for erasing the disk, so that the erasing field or emanation need not penetrate the sealed housing to effectuate erasure. A backup power supply provides power to the erasing device so that erasure can occur even in the absence of external power. A bus- or network-actuated arrangement couples power to the erasure device so that many hard drives may be simultaneously erased.Type: GrantFiled: August 14, 2006Date of Patent: April 27, 2010Assignee: Lockheed Martin CorporationInventors: Vladimir Gershman, Ronald Dean, Bernard McGrath
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Patent number: 7707371Abstract: Techniques are provided for performing multi-pass erase. An erase command is received at a storage area network (SAN) switch in a storage area network. The erase command is associated with a block of data on a target device. A virtual initiator is determined for performing the erase command on the block of data. Multiple bit patterns are generated using a multi-pass erase algorithm. The multiple bit patterns are generated for writing over the block of data on the target device. Repeated writes are performed over the block of data using the bit patterns. The block of data is repeatedly overwritten to remove remanence of the block of data on the target device.Type: GrantFiled: September 10, 2007Date of Patent: April 27, 2010Assignee: Cisco Technology, Inc.Inventors: Muhammad Asim Goheer, Maurilio Cometto, Prashant Billore
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Publication number: 20100079912Abstract: A magnetic recording device includes a write head, a perpendicular magnetic recording medium, a recording-current generating circuit, and a setting circuit. The perpendicular magnetic recording medium includes a plurality of tracks that includes a recording track. The recording-current generating circuit generates a recording electric current. The write head supplied with the recording current writes a recording data pattern on the recording track. The setting circuit sets a value of the recording electric current such that the value of the recording electric current decreases as a magnitude of side erase effect on at least one track of the tracks adjacent to the recording track increases.Type: ApplicationFiled: July 30, 2009Publication date: April 1, 2010Applicant: FUJITSU LIMITEDInventors: Hiroyuki Hama, Masahiko Miyake
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Patent number: 7623310Abstract: Disclosed is a magnetic recording medium which enables a magnetic head to be accurately positioned even if higher-density recording of magnetic recording media is reinforced. The magnetic recording medium includes at least one servo band being magnetized in one direction and including a plurality of servo patterns being formed repeatedly along a long side of the servo band. Furthermore, each of the servo patterns includes a first magnetizing area being formed across a width of the servo band at an angle from 8 to 20 degrees with respect to the width, and a second magnetizing area being formed across the width of the servo band in non-parallel with the first magnetizing area. In addition, the first and second magnetizing areas are magnetized in a direction opposite to that of the servo band.Type: GrantFiled: May 16, 2005Date of Patent: November 24, 2009Assignee: FUJIFILM CorporationInventor: Toru Nakao
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Patent number: 7576949Abstract: The present invention relates to direct current (“DC”) pre-erasing servo channels of a magnetic tape prior to writing servo data in a servo channel. The present invention particularly relates to those servo recordings which were written with a uni-polar current waveform. The DC pre-erase is performed using a uni-polar direct current of a polarity that is opposite to the polarity of the direct current used to write the servo data. This pre-erase may be done with one or more heads. Also, as will be described, the pre-erase of a servo channel and writing to a servo channel may be done by making two passes over a single head or by using two or more heads to perform both steps. Also, it is within the scope of the present invention to have the heads mounted on a single mount or have the heads on separate mounts and on separate tape decks.Type: GrantFiled: August 13, 2007Date of Patent: August 18, 2009Assignee: Advanced Research CorporationInventors: Matthew P. Dugas, Theodore A. Schwarz
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Publication number: 20090190255Abstract: A hard disk drive is disclosed with a slider including a wide track eraser for erasing neighboring tracks and the servo patterning around a track on the accessed disk surface. Using the wide track eraser reduces the time to erase a disk surface by at least a factor of N, where N is at least 4, and may preferably be successively larger to at least 64. Embodiments include the slider, a head gimbal assembly, a main flex circuit, an integrated circuit for the main flex circuit for stimulating the wide track eraser, a head stack assembly including the main flex circuit coupling through the head gimbal assembly to the wide track eraser, a control circuit, and a processor within the control circuit controlling the stimulus of the wide track eraser to erase part or all of a disk surface.Type: ApplicationFiled: January 24, 2008Publication date: July 30, 2009Inventor: Eun Kyu Jang
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Patent number: 7561378Abstract: A data erasing device that erases data recorded on a magnetic disk, by a magnetic field generated in a horizontal direction by magnets, in order to prevent leakage of the data recorded on the magnetic disk of a magnetic disk device to be abandoned. The data erasing device includes a main body case having a path on which a tray is reciprocated, a demagnetizing circuit having plural permanent magnets adjacently disposed along the path in mutually adsorbing polarities, and a tray for accommodating the magnetic recording medium, and capable of reciprocating on the path. This tray includes a first accommodation groove and a second accommodation groove for accommodating the magnetic disk device. The first accommodation groove and the second accommodation groove cross each other to form an angle of 45 degrees or 90 degrees.Type: GrantFiled: December 20, 2005Date of Patent: July 14, 2009Assignee: Fujitsu LimitedInventors: Yoshinori Kadowaki, Hisato Suzuki, Hiroyuki Uematsu, Hiroshi Hasegawa
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Publication number: 20090067087Abstract: The present invention relates to direct current (“DC”) pre-erasing servo channels of a magnetic tape prior to writing servo data in a servo channel. The present invention particularly relates to those servo recordings which were written with a uni-polar current waveform. The DC pre-erase is performed using a uni-polar direct current of a polarity that is opposite to the polarity of the direct current used to write the servo data. This pre-erase may be done with one or more heads. Also, as will be described, the pre-erase of a servo channel and writing to a servo channel may be done by making two passes over a single head or by using two or more heads to perform both steps. Also, it is within the scope of the present invention to have the heads mounted on a single mount or have the heads on separate mounts and on separate tape decks.Type: ApplicationFiled: November 14, 2008Publication date: March 12, 2009Inventors: Matthew P. Dugas, Theodore A. Schwarz
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Patent number: 7394619Abstract: An inductive write head has its write poles and write gap oriented to generate magnetic fields in the cross-track direction on a magnetic recording disk in a disk drive. The disk has the magnetizations in the concentric data tracks oriented in the cross-track direction with the concentric data tracks magnetically separated from each other by guard bands. The write head may have an erase pole and an erase gap to generate magnetic fields in an along-the-track direction on the sides of the data tracks, with the along-the-track magnetizations serving as the guard bands.Type: GrantFiled: November 30, 2004Date of Patent: July 1, 2008Assignee: Hitachi Global Storage Technologies Netherlands B.V.Inventor: Vladimir Nikitin
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Patent number: 7256962Abstract: A magnetic head including a plurality of head element units provided along a width direction with respect to a magnetic tape. Each head element unit is provided with at least one recording element for recording a data signal on the magnetic tape and at least one reproducing element for reproducing a data signal from the magnetic tape. In each head element unit, an AC erase head for performing AC erase on a data track of the magnetic tape is positioned upstream in a tape travel direction with respect to the recording element.Type: GrantFiled: August 4, 2004Date of Patent: August 14, 2007Assignee: Fujifilm CorporationInventor: Seiji Tateishi
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Patent number: 7027709Abstract: The invention provides a simple method for forming a gap for an erasure head to improve the quality of this erasure head. A front core 3 constituting an erasure head H includes in configuration two magnetic substances 5 and a magnetic gap 6 made of a non-magnetic substance arranged between these two magnetic substances 5, in which the gap 6 made of the non-magnetic substance is bonded by adhesion or welding between those two magnetic substances 5. By this method, the gap can be formed free of an air bubble, with good mass-productivity, and inexpensively as compared to a prior art method of forming a gap by glass bonding.Type: GrantFiled: May 1, 2001Date of Patent: April 11, 2006Assignee: Funai Electric Co., Ltd.Inventors: Kiyoshi Matsui, Yoshinobu Umaji
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Patent number: 6822827Abstract: Methods and apparatus for erasing magnetic tape are described. The tape to be erased is fed through an erasure unit that includes an array of magnetic elements. The array of magnetic elements includes a first set of magnetic elements and a second set of magnetic elements. The magnetic fields for the respective first and second sets of magnetic elements have opposite polarity, as seen by the tape as it feeds through the erasure unit. The fields seen by the tape as it feeds through the erasure unit decrease in intensity.Type: GrantFiled: June 7, 2001Date of Patent: November 23, 2004Assignee: Imation Corp.Inventors: John E. Heinz, Curtis B. Hause, Helen J. Yoo
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Publication number: 20040075941Abstract: A front core for a magnetic erase head is produced by a method that includes forming a pair of elongate magnetic bars by sintering such that they can be combined with a gap therebetween, holding the magnetic bars with a predetermined space to form a recess and a gap groove, pouring a resin into the recess and the gap groove to join the magnetic bars, and grinding the magnetic bars joined to each other. This allows the recess and the gap groove to be formed through no cutting process, thus contributing to reduction in time required for the process and to decrease in consumption of grindstone for cost reduction.Type: ApplicationFiled: October 14, 2003Publication date: April 22, 2004Applicant: Funai Electric Co., Ltd.Inventor: Kazuki Soejima
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Patent number: 6714398Abstract: A bulk degaussing apparatus and method for erasing magnetic media of various sizes. A media passage track is provided such that media passing therethrough is uniformly exposed to the magnetic fields provided through the gap. The bulk degaussing apparatus has fixed magnetic pole pairs predisposed for generating uniform magnetic field elements across a gap projecting magnetic flux across the gap for erasing various sizes of magnetic media, with the magnetic media receiving track positioned relative to the poles such that adjacent like poles are arranged on each side of the gap to counteract fringing effects. The bulk degaussing method for erasing various sizes of magnetic media provides a plurality of fixed magnetic pole pairs for generating uniform magnetic field elements on one or more sides of a degaussing region projecting magnetic flux into the region, and arranges the plurality of fixed poles so that adjacent poles counteract fringing effects.Type: GrantFiled: June 7, 2002Date of Patent: March 30, 2004Assignee: Data Security, Inc.Inventor: Robert A. Schultz
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Publication number: 20020001156Abstract: The invention provides a simple method for forming a gap for an erasure head to improve the quality of this erasure head. A front core 3 constituting an erasure head H includes in configuration two magnetic substances 5 and a magnetic gap 6 made of a non-magnetic substance arranged between these two magnetic substances 5, in which the gap 6 made of the non-magnetic substance is bonded by adhesion or welding between those two magnetic substances 5. By this method, the gap can be formed free of an air bubble, with good mass-productivity, and inexpensively as compared to a prior art method of forming a gap by glass bonding.Type: ApplicationFiled: May 1, 2001Publication date: January 3, 2002Inventors: Kiyoshi Matsui, Yoshinobu Umaji
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Patent number: 6072668Abstract: Disclosed is a full width erase head assembly for a magnetic reproducer. According to the present invention, a horizontal flow preventing member is extended to a predetermined angle from a rear side portion of the body which is installed on the main base. A vertical flow preventing member which is parallel to the horizontal flow preventing member and faces mutually opposite direction around the body of the FE head are installed at a lower portion of the body of the FE head compared to the height of the horizontal flow preventing member.Type: GrantFiled: July 27, 1998Date of Patent: June 6, 2000Assignee: Samsung Electronics Co., Ltd.Inventor: Myoung-sub Jang
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Patent number: 6064537Abstract: A floppy disk drive comprises a read/write head and a pair of erase heads. The read/write head has a gap that extends across and beyond opposite edges of a track, while the gaps of the erase heads are aligned with each other and extend from the opposite edges of the track to create a pair of erased regions on opposite sides of the track. A wire circuit activates the read/write head in response to an output signal from a host system for recording signals along a sector of a track. An erase circuit activates the erase heads in response to the output of the host system for creating the erased regions along a length that corresponds to the sector. A fault detector is provided for detecting a potential developed by the erase heads to allow the write circuit to respond to the output of the host system when the potential is high and prevent the read/write head from responding to the output when the potential is low.Type: GrantFiled: March 22, 1996Date of Patent: May 16, 2000Assignee: NEC CorporationInventor: Yoshihisa Okawa
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Patent number: 6040963Abstract: A multi-track servo recording head assembly records a plurality of identical tracks of servo information longitudinally defined within a very high density servo section along a magnetic recording medium. The servo recording head assembly includes a write transducer for writing a servo signal, as well as an erase transducer that includes two outer erase elements and at least one inner erase element positioned between the two outer erase elements. Each erase element erases alternating portions of the servo signal to create at least one of the plurality of tracks of servo information in the servo section. The outer erase element and the inner erase element are positioned transversely across the servo section, with the inner erase elements having an erase head width that is less than an erase head width of the outer erase elements.Type: GrantFiled: June 22, 1999Date of Patent: March 21, 2000Assignee: Imation Corp.Inventor: Stephen J. Rothermel
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Patent number: 5979774Abstract: A magnetic display erasing apparatus is provided in which an ideal erasing magnetic field can be realized by using a small-sized magnet. A magnet is formed by bending a rectangular plate-like magnet, having the N-pole on the surface and the S-pole on the back face, into a U-shape so that the N-pole of one end of the magnet confronts the N-pole of the other end thereof symmetrically with respect to a magnetic display sheet. The magnetic display sheet is conveyed by a conveying apparatus, which is not shown, in the U-shaped gap space which is formed by the magnet. Because the magnetic field is symmetrical with respect to the plane of the magnetic display sheet, an ideal planar magnetic field is attained on the disposition plane of the magnetic display sheet. There is no point where the strength of the magnetic field is zero. Therefore, the whole region of the empty space can be used for erasure and the space utilization efficiency of the magnet is enhanced.Type: GrantFiled: November 26, 1996Date of Patent: November 9, 1999Assignee: Star Micronics Co., Ltd.Inventor: Kiyoshi Urushibata
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Patent number: 5959812Abstract: A multi-track servo recording head assembly records a plurality of identical tracks of servo information longitudinally defined within a very high density servo section along a magnetic recording medium. The servo recording head assembly includes a write transducer for writing a servo signal, as well as an erase transducer that includes two outer erase elements and at least one inner erase element positioned between the two outer erase elements. Each erase element erases alternating portions of the servo signal to create at least one of the plurality of tracks of servo information in the servo section. The outer erase element and the inner erase element are positioned transversely across the servo section, with the inner erase elements having an erase head width that is less than an erase head width of the outer erase elements.Type: GrantFiled: July 25, 1997Date of Patent: September 28, 1999Assignee: Imation Corp.Inventor: Stephen J. Rothermel
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Patent number: 5953482Abstract: A magnetic recording/reproducing apparatus is provided in which among diametrically oppositely disposed heads, a recording head and an erasing head of a same channel are disposed adjacently to each other. The recording head is disposed so as to precede by two tracks the erasing head with respect to a direction of cylinder rotation, when insert-editing, using a reproduced signal obtained by the recording head, erase and record timing setting and head tracking are performed and an erasing current is not applied during the reproduction by the recording head. The reproducing heads are disposed so as to be angularly apart by about 90 degrees from the recording and erasing heads, and a rotary transformer for reproduction is applied with a shield measure and then, formed as a core independently at an upper portion of the cylinder. In addition, more narrow tracks are compatibly reproduced by the recording head.Type: GrantFiled: September 22, 1997Date of Patent: September 14, 1999Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Kouhei Suzuki, Haruo Ohta, Hideaki Mukae, Jun Takeuchi, Haruo Isaka
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Patent number: 5822160Abstract: A full erase head assembly for erasing a signal recorded on a tape includes a full erase head, a guide post installed on a deck base for guiding the tape, a guide portion formed on a first side of the full erase head, the guide portion being supported by the guide post, and a locking mechanism formed on a second side of the full erase head and coupled to the deck base, the locking mechanism preventing the full erase head from separating from the deck base.Type: GrantFiled: February 14, 1996Date of Patent: October 13, 1998Assignee: LG Electronics Inc.Inventor: Ji Young Lee
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Patent number: 5742460Abstract: A full erasing head unit disposed on a deck chassis of a video cassette recorder includes a full erasing head, a base plate for mounting the full erasing head thereon in such a way that the full erasing head comes into contact with a traveling tape, the base member movably disposed on the deck chassis, a resilient member for exerting an elastic force on the base plate, a pin provided at the deck chassis and coming into contact with the resilient member in such a way that the resilient member biased by a tape tension is allowed to return to an initial position thereof, thereby additionally performing the role of the impedance roller.Type: GrantFiled: November 26, 1996Date of Patent: April 21, 1998Assignee: Daewoo Electronics Co., Ltd.Inventor: Ki-Young Park
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Patent number: 5537277Abstract: A magnetic head for sliding on a recording medium for executing magnetic recording or magnetic reproducing of information includes a magnetic core having a recording/reproducing magnetic gap whose track width is defined narrow in accordance with high-ranking high track density, and an erasing magnetic gap which is disposed upstream of a medium-sliding direction, in such a manner that the erasing magnetic gap is adjacent to the recording/reproducing gap, and whose track width is defined wide in accordance with low-ranking low track density. A center of the recording/reproducing magnetic gap in a direction perpendicular to the track is shifted by a predetermined amount of shift in the direction perpendicular to the track with respect to a center of the erasing magnetic gap in the direction perpendicular to the track.Type: GrantFiled: October 2, 1991Date of Patent: July 16, 1996Assignee: Canon Denshi Kabushiki KaishaInventor: Minoru Kato
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Patent number: 5428892Abstract: In a method of manufacturing a tunnel erase type combined magnetic head core using a first core member having a predetermined pole height dimension defined by a surface on a magnetic gap formation side and an apex, and a predetermined back height dimension defined by the apex and a bottom of a coil core into which a coil is inserted, and a second core member, the bottom of the coil core of the first core member is used as a back height reference face and the combined magnetic head core is manufactured with the back height reference face as reference, thereby facilitating processing of a surface on the pole height side at intermediate steps, namely, a final contact face with which magnetic recording media are brought into contact. Since the back height reference face is used as reference, when combined core chips are incorporated into sliders to manufacture magnetic heads, the process is not affected by variations in core dimensions.Type: GrantFiled: August 31, 1993Date of Patent: July 4, 1995Assignee: Citizen Watch Co., Inc.Inventor: Makoto Wakasugi
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Patent number: 5414652Abstract: A magneto-optical memory element including: grooves, formed on at least one surface of a transparent substrate, for guiding a light beam; a magneto-optical recording layer formed on the surface of said transparent substrate on which the grooves are formed, wherein a width of each groove and a width of each land formed between the grooves are substantially equal, information is recorded on and reproduced from tracks on the grooves and the lands, and a groove depth d (track depth) is arranged such that 0.13.times..lambda./n.ltoreq.d.ltoreq. 0.18.times. .lambda./n, where .lambda. is a wavelength of the light beam and n is a refraction index of the transparent substrate. Assuming that a diameter of the light beam at a portion where a light intensity of the light beam becomes 1/e.sup.2 of a light intensity of the center of the light beam is L, a track pitch p is arranged such that 0.6.ltoreq.L/p.ltoreq.1.2. Therefore, even when the track density is increased, i.e.Type: GrantFiled: August 22, 1994Date of Patent: May 9, 1995Assignee: Sharp Kabushiki KaishaInventors: Michinobu Mieda, Hiroyuki Katayama, Akira Takahashi, Kenji Ohta
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Patent number: 5309296Abstract: A magnetic disk drive is disclosed which has a tunnel erase head assembly comprising a read/write head for writing and reading data on a magnetic disk, and a pair of tunnel erase heads for trimming a pair of opposite marginal edges of the record track being formed by the read/write head, with the consequent formation of spaces intervening between the record tracks. The spaces created on the same disk by different disk drives may be of one polarity of magnetization or the other, with the possibility of noise production due to an abrupt change in the polarity of magnetization as the read/write head scans any of the spaces as a result of mistracking. For the reduction of such noise the coil of the tunnel erase heads is connected to an erase current source via a circuit whereby the erase current is made to have a staircase or ramp rise and fall.Type: GrantFiled: December 3, 1991Date of Patent: May 3, 1994Assignee: TEAC CorporationInventors: Fumio Nagase, Tohru Miura, Hiroshi Tsuyuguchi
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Patent number: 5243483Abstract: This invention relates to a rotary drum device used in magnetic recording and playback apparatus such as VTRs, and particularly to the structure of a magnetic head and flying erasure head mounted on the rotary drum. The flying erasure head and recording head are of virtually same design, with the erasing frequency being set lower than the recording frequency with the intention of obliterating the old record instead of erasing it completely, and the flying erasure head has an azimuth angle of 0.degree. and operates for erasing the old record at a frequency close to the maximum recording frequency of the apparatus, allowing the erasure of record of any particular channel. The flying erasure head and recording head of the virtually same shape reduce their manufacturing cost. The erasing frequency lower than the recording frequency effects the head isolation, and the flying erasure head can be mounted without special shielding measures against such defective performance as crosstalk.Type: GrantFiled: August 7, 1991Date of Patent: September 7, 1993Assignee: Hitachi, Ltd.Inventors: Hiroaki Ono, Tomomi Okamoto, Seiji Ono, Shinji Ozaki
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Patent number: 5229903Abstract: The structure of a magnetic head for use in a disk drive has an erase core and a read/write core which are inclined to a track of a floppy disk or disket. An erase gap and a read/write gap formed in the erase core and read/write core, respectively, each is inclined by a different angle to the longitudinal axis of the magnetic head. A shield plate is interposed between the two cores for magnetically shielding them from each other. With this configuration, the magnetic head reduces crosstalk ascribable to flux picked up by the erase core from the track.Type: GrantFiled: January 25, 1991Date of Patent: July 20, 1993Assignee: NEC CorporationInventors: Yuichi Hayakawa, Atsushi Hirano
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Patent number: 5181150Abstract: A dual magnetic head capable of reducing unneccessary magnetic flux developed in erase cores. The dual magnetic head includes a first read/write core (30) having a first gap width (34) and extending in a track direction in which the tracks will be formed on a magnetic recording medium, a second read/write core (10) having a second read/write gap (14) with a width greater than the first gap width, and juxtaposed to the first read/write core (30) in a perpendicular direction to the track direction; and an erase core (20) having a pair of erase gaps (24, 25) located at opposite ends of the second read/write gap (14) with respect to the perpendicular direction, the erase core (20) being juxtaposed to the first read/write core (30) in the perpendicular direction and juxtaposed to the second read/write core (10) in the track direction, at least one of the facing surfaces of the erase core (20) which define the erase gaps (24, 25) therebetween being provided with an undulation.Type: GrantFiled: March 29, 1991Date of Patent: January 19, 1993Assignee: NEC Corp.Inventors: Yuichi Hayakawa, Takeshige Iwakura, Hiroshi Tsutsui, Atsushi Hirano, Makoto Miyazaki
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Patent number: 5138508Abstract: A composite magnetic head core with a writing/reading track and two erasing tracks, including a first ferrite block, and a second and a third ferrite block bonded to opposite surfaces of the first block interposed therebetween. The opposite abutting surfaces of the first block have respective first and second recessed portions, and a first rectangular protrusion and two second rectangular protrusions which protrude from the first and second recessed portions, respectively. The first protrusion is positioned between the two second protrusions in a direction of width of the writing/reading and erasing tracks. The first protrusion cooperates with the second block, to define a writing/reading magnetic gap of the writing/reading track, while the second protrusions cooperate with the third block, to define two erasing magnetic gaps of the erasing tracks. The first protrusion has a width defining the width of the writing/reading track, and a longitudinal end defining a depth of the writing/reading magnetic gap.Type: GrantFiled: February 14, 1991Date of Patent: August 11, 1992Assignee: NGK Insulators, Ltd.Inventors: Soichiro Matsuzawa, Fuminori Takeya, Nobuhiro Terada
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Patent number: 5132860Abstract: An erasure system for magnetic information storage media is disclosed by which magnetic media, such as computer, video and audio tapes, cassettes and discs, can be thoroughly erased. The system uses high energy product permanent magnets preferably positioned so that their poles repel one another to induce "bucking magnetic fields" having lines of force active in the three spatial planes and parallel or tangential to the recorded signal track on the media being erased. The DC magnetic field thus applied causes the DC erasure of the media. The AC erasure effect comes about through the relative movement of the media through fixed magnetic fields of opposite polarity, causing the magnetic media to be subjected to a reversing polarity of magnetic saturation. The magnet configurations can be adjusted for use on helically recorded magnetic media, in addition to cross-field and conventional recording techniques.Type: GrantFiled: October 13, 1989Date of Patent: July 21, 1992Inventor: Paul W. Von Stein
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Patent number: 5122916Abstract: In a magnetic sensing head with reduced crossfeed interference circuitry, the winding of each half of a magnetic core of the head is wound in the same direction as the other about the core. Each winding is coupled to an individual differential amplifier and the output of each amplifier is fed to another differential amplifier which provides the head output substantially unaffected by interference signals picked up by the head. Both magnetically coupled and stray capacitive interference are compensated.Type: GrantFiled: July 16, 1991Date of Patent: June 16, 1992Assignee: Archive CorporationInventor: Anatoly Aranovsky
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Patent number: 5061842Abstract: A card reader having a card reading mechanism, a card perforating device and a card erasure mechanism, wherein the erasure mechanism comprises a permanent magnet movable by means of a pivoted arm towards and away from a card erasure position, and a drive means for the magnet arm which is coupled to a motor drive for the perforating device.Type: GrantFiled: July 3, 1989Date of Patent: October 29, 1991Assignee: Ampy Automation - Digilog LimitedInventor: Kenneth Payne
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Patent number: 5041936Abstract: A magnetic transducer assembly for cooperating with a relatively moving magnetic recording medium to magnetically record and reproduce information on and from the magnetic recording medium. The transducer assembly comprises first and second magnetic transducers incorporated into one rail of a double-rail type slider with they are adjacent to each other. The rail has a contacting surface with a recording surface of the recording medium in recording and reproducing. The first magnetic transducer includes a first read/write core assembly having a first magnetic gap extending in directions normal to the moving direction of the recording medium and placed in a plane including the contacting surface of the rail. The second magnetic transducer includes a second read/write core assembly having a second magnetic gap which is different in length from the first magnetic gap and extends in directions normal to the moving direction thereof.Type: GrantFiled: August 9, 1989Date of Patent: August 20, 1991Assignee: NEC CorporationInventor: Yuichi Hayakawa
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Patent number: 5021895Abstract: A method of recording signals on a magnetic medium, in which a first magnetic head (1) blanks a wide track by recording signals at a first azimuth angle and a second magnetic head (2) records a narrower signal track (15) by recording signals at a second, differing azimuth angle. This permits feeding the same current or signal through the head windings (8,9) of both heads, thereby economizing on driving circuitry (10). Due to the differing azimuth angles, the reading head does not pick up any significant amount of noise from the border regions defined between the edges of the signal track and the wider blanking track. The width of the signal track and the widths of the border regions sum to equal the width of the blanking track.Type: GrantFiled: December 1, 1989Date of Patent: June 4, 1991Assignee: BTS Broadcast Television Systems GmbHInventor: Jurgen Heitmann
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Patent number: 4996620Abstract: A magnetic transducer of the erasing type, in which the coil is pre-wound to achieve greater manufacturing economy; and in which for the same reason, and also for electromagnetic operating efficiency, the core is laminated with each lamination being of one-piece fabrication. However, the single transducing gap in the core is too small to permit threading the coil thereon. Therefore, the core is formed of flexible material so that the gap can be enlarged to accept the coil during assembly. Alternatively, the core can be fabricated initially with an enlarged gap, and the flexible core is then bent to provide a desired gap length after the coil is assembled thereon. A variational form of the invention has two erase gaps and one record-play gap with a separate coil therefor.Type: GrantFiled: November 9, 1989Date of Patent: February 26, 1991Assignee: Ampex CorporationInventor: Gregory A. Orton
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Patent number: 4965688Abstract: A permanent magnet type demagnetizing head is made by successively molding a resin-magnet which forms a body having a magnetic member forming a part of a tape contact surface and a resin which forms protection member forming a remainder part of the tape contact surface, and therefore a manufacturing process is simplified, and further quality of the demagnetizing head is improved, since size precision is enhanced.Type: GrantFiled: March 23, 1990Date of Patent: October 23, 1990Assignee: Matsushita Electric Industrial Co., Ltd.Inventor: Tuyoshi Yoshino
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Patent number: RE39029Abstract: A magnetic recording/reproducing apparatus is provided in which among diametrically oppositely disposed heads, a recording head and an erasing head of a same channel are disposed adjacently to each other. The recording head is disposed so as to precede by two tracks the erasing head with respect to a direction of cylinder rotation, when insert-editing, using a reproduced signal obtained by the recording head, erase and record timing setting and head tracking are performed and an erasing current is not applied during the reproduction by the recording head. The reproducing heads are disposed so as to be angularly apart by about 90 degrees from the recording and erasing heads, and a rotary transformer for reproduction is applied with a shield measure and then, formed as a core independently at an upper portion of the cylinder. In addition, more narrow tracks are compatibly reproduced by the recording head.Type: GrantFiled: January 24, 2003Date of Patent: March 21, 2006Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Kouhei Baba, Haruo Ohta, Hideaki Mukae, Jun Takeuchi, Haruo Isaka