With Magnetic Bias Patents (Class 360/17)
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Publication number: 20090073593Abstract: A master carrier for magnetic transfer includes a transfer portion on which a magnetic layer corresponding to magnetic information for transfer is formed, and a non-transfer portion forming a concave shape relatively low with respect to the transfer portion having the magnetic layer, wherein the magnetic layer of the transfer portion has perpendicular magnetic anisotropy, with residual magnetization Mr of 500 emu/cc or less, and saturation magnetization Ms of 900 emu/cc or more. CoPt can be used as a material of the magnetic layer, and use of Co4Pt1 (at %) is especially preferable. Thereby, a master carrier for magnetic transfer which can generate a high magnetic field capable of transfer of a short bit to a high density medium is provided.Type: ApplicationFiled: September 10, 2008Publication date: March 19, 2009Applicant: FUJIFILM CorporationInventors: Naoto FUJIWARA, Makoto Nagao, Ryuji Sugita
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Patent number: 7502184Abstract: When magnetically transferring information represented by a pattern of magnetic layer formed on a master information carrier to a disc-like slave medium, an initial DC magnetic field is applied to the slave medium to initially magnetize the slave medium in one direction of concentric recording tracks and a transfer magnetic field is applied to the slave medium in the direction opposite to the direction of the initial-magnetization with the initially-magnetized slave medium held in close contact with the master information carrier. At least one of applying the initial DC magnetic field and applying the transfer magnetic field is effected by applying the magnetic field while the slave medium is being rotated relatively to the magnetic field and stopping the rotation of the slave medium after the intensity of the magnetic field is gradually reduced to not stronger than a predetermined value.Type: GrantFiled: February 8, 2006Date of Patent: March 10, 2009Assignee: FUJIFILM CorporationInventors: Kazuhiro Niitsuma, Masakazu Nishikawa
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Patent number: 7477464Abstract: When copying servo information from an electro-magnetic field copy master to a vertical storage medium, the magnetization direction of the vertical storage medium is made to the direction the reverse of an external electro-magnetic field applied to the vertical storage medium and the electro-magnetic field copymaster, the vertical storage medium is closely touched on the electromagnetic field copy master provided with a substrate which has concavity/convexity corresponding to the servo information and at least the convex part of which of the concavity/convexity is made of a softly magnetic material and a conductor installed in the concave part of the substrate and an external electro-magnetic field stronger than the coercive field strength of the vertical storage medium is instantaneously applied to the vertical storage medium and the electromagnetic field copy master.Type: GrantFiled: August 21, 2006Date of Patent: January 13, 2009Assignee: Fujitsu LimitedInventor: Sumio Kuroda
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Patent number: 7477463Abstract: A master information carrier has on its surface a signal area where an embossed pattern formed by protruding portions and recessed portions and representing a signal pattern to be transferred has been formed. The shortest bit length of the embossed patter is 300 nm or shorter, and the embossed pattern is formed so that the total of the areas of the upper surfaces of the protruding portions of the embossed pattern is smaller than the total of the areas of inter-protruding-portions in the signal area.Type: GrantFiled: February 4, 2004Date of Patent: January 13, 2009Assignee: FUJIFILM CorporationInventors: Tadashi Yasunaga, Masakazu Nishikawa
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Patent number: 7460322Abstract: A magnetic transferring apparatus allows attachment of a first magnet to a first holder. A second magnet is attached to a second holder. The first and second holders are located in a space between first and second magnets. A magnetic disk and a master member are located in a space between the first and second holders. The magnetic attraction is generated between the first and second magnets. The magnetic attraction serves to bring the first and second holders closer to each other, so that magnetic pieces of the master member is brought in a close contact with the magnetic disk between the first and second holders. The magnetic flux runs between the first and second based on the contact between the magnetic pieces and the magnetic disk. A servo pattern can in this manner be established in the magnetic disk.Type: GrantFiled: March 28, 2006Date of Patent: December 2, 2008Assignee: Fujitsu LimitedInventors: Hiroyuki Suzuki, Sumio Kuroda, Yutaka Nakamura
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Patent number: 7440207Abstract: Provided is a method of magnetic transfer. The method includes initially DC-magnetizing a transfer-recipient disc in a circumferential direction, by applying a magnetic field to the transfer-recipient disc in the circumferential direction thereof bringing initially DC-magnetized transfer-recipient disc and a master disc into close contact with each other, on the top side of the master disc a magnetic layer including a great number of protrusions that configure a magnetic pattern being formed; and executing magnetic transfer in such a way that a magnetic-field generation device is provided, and that, when a magnetic field is applied in a circumferential direction to the transfer-recipient disc and the master disc, transfer of the magnetic pattern of the master disc onto the transfer-recipient disc occurs.Type: GrantFiled: October 13, 2005Date of Patent: October 21, 2008Assignee: FUJIFILM CorporationInventors: Makoto Nagao, Satoshi Wakamatsu, Minoru Araki, Kazunori Komatsu
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Publication number: 20080239533Abstract: The present invention provides a method of magnetic transfer comprising: an initial magnetization step of performing an initial magnetization by applying a DC magnetic field perpendicular to a disk shaped perpendicular magnetic recording medium which is formed by laminating a soft magnetic layer and a magnetic layer on a substrate; an initial magnetization cleaning step of applying an in-plane magnetic field having an intensity larger than 100 [Oe] and less than an intensity of Hn, to the perpendicular magnetic recording medium after passed through the initial magnetization step in radial direction which directed from a center to an outer of the perpendicular magnetic recording medium. After or in a time of the magnetic transfer, a magnetic cleaning may be performed by applying an in-plane magnetic field having the same intensity as the initial magnetization cleaning step in radial direction instead of the initial magnetization cleaning or in combination.Type: ApplicationFiled: March 30, 2008Publication date: October 2, 2008Applicant: FUJIFILM CorporationInventors: Makoto Nagao, Naoto Fujiwara, Tadashi Yasunaga, Ryuji Sugita, Takashi Komine
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Patent number: 7420757Abstract: A magnetic transfer wherein the exchange of master mediums is made easy to perform is provided, whereby the operational efficiency and transfer efficiency are improved, leading to an overall improvement in productivity in the manufacture of preformatted slave mediums. A master fixing base for determining and supporting the position of a master medium, which bears transfer data, and a conjoining apparatus for conjoining the master medium and the slave medium that is to receive the transfer therefrom are provided. The master medium is exchanged along with the master fixing base. It is preferable that a cleaning means be provided.Type: GrantFiled: May 12, 2005Date of Patent: September 2, 2008Assignee: FUJIFILM CorporationInventors: Akito Kamatani, Tsuneo Inui, Masashi Aoki, Masakazu Nishikawa
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Patent number: 7385774Abstract: A master information carrier for magnetic transfer bears uneven signal patterns on its surface. When the minimum bit length in the uneven signal patterns is Bmin, dummy uneven patterns are provided in a depression of the uneven signal patterns, which has a length of 4Bmin or longer in the direction along a track. When magnetic transfer is performed, magnetized patterns corresponding to the dummy uneven patterns are transferred onto a slave medium. The magnetized patterns are patterns which will not be recognized as reproduction signals at a drive, into which the slave medium after magnetic transfer will be loaded.Type: GrantFiled: March 24, 2005Date of Patent: June 10, 2008Assignee: FUJIFILM CorporationInventors: Masakazu Nishikawa, Makoto Nagao
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Patent number: 7382558Abstract: By bring a master carrier and a slave medium into close contact with uniform force when executing magnetic transfer by applying transfer magnetic field in the state that the master carrier and slave medium is in confronted close contact and received within a holder, inferiority of transfer such as omission of signals is prevented and quality of transfer signals is enhanced. The magnetic transfer apparatus executes magnetic transfer by applying transfer magnetic field by means of a magnetic field applying apparatus 5 after a master carrier 3, 4 bearing transfer information and a slave medium 2 to be transferred are brought into confronted close contact and received within a holder 10, wherein said holder 10 has a substantially circular shape and in particular, the circularity of holder is not less than 98%, wherein the flexural rigidity=Ed3/12 determined by Young's modulus E and thickness d of the holder is in the range of 0.Type: GrantFiled: May 5, 2005Date of Patent: June 3, 2008Assignee: FUJIFILM CorporationInventors: Masakazu Nishikawa, Kazuhiro Niitsuma, Akito Kamatani
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Patent number: 7369337Abstract: A magnetic field application apparatus includes a pair of magnetic field application means, each of which is arranged, at least during application of a magnetic field, on either side of a magnetic field application target so as to face each other, and which generate a magnetic field in a predetermined direction. Each of the magnetic field application means includes a pair of magnetic portions which generate a magnetic field in a desired direction from one of the magnetic portions toward the other magnetic portion, and of which the polarities on the side facing the magnetic field application target are different from each other. Each of the pair of magnetic portions is formed so that magnetic force applied to the magnetic field application target becomes weaker stepwise or continuously from the side of the magnetic portion, facing the other magnetic portion, toward the opposite side thereof.Type: GrantFiled: January 17, 2006Date of Patent: May 6, 2008Assignee: Fujifilm CorporationInventor: Michinobu Fujisawa
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Patent number: 7369336Abstract: A master carrier for magnetic transfer having a data region and a servo pattern region that has a pattern of fine projections arrayed in the track direction thereof in accordance with the preformat signal information to be transferred onto an in-plane magnetic recording medium is disclosed. The data region has a projection formed of a material such as carbon-based material that differs from the material of the servo pattern region.Type: GrantFiled: July 21, 2004Date of Patent: May 6, 2008Assignee: FUJIFILM CorporationInventors: Hideyuki Kubota, Akito Kamatani, Masakazu Nishikawa
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Patent number: 7365926Abstract: When signals are read out by a magnetic head from a magnetic recording medium on which magnetic bits corresponding to information are recorded along the tracks thereof by a magnetic transfer method, if a space which is longer than or equal to a length corresponding to three bits is present between consecutive magnetic bits, readout of signals from a sub-pulse generation area in the space is cancelled in readout of the magnetic bits by the magnetic head along the tracks. The signals are not read out at all, or even if the signals are read out, they are not processed as valid signals.Type: GrantFiled: September 20, 2005Date of Patent: April 29, 2008Assignee: FUJIFILM CorporationInventors: Makoto Nagao, Tadashi Yasunaga
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Patent number: 7362524Abstract: A magnetic pattern transfer method is disclosed. A magnetic pattern transfer master having a plurality of magnetic portions preformed with predetermined magnetic patterns is brought in proximity to a magnetic recording medium having a magnetic film to record the magnetic information, and a magnetic field is applied from an external source thereby to transfer the magnetic patterns to the magnetic recording medium. In order to improve the closeness between the magnetic film of the magnetic recording medium and the magnetic portions of the magnetic pattern transfer master, the magnetic patterns are transferred to the magnetic film of the magnetic recording medium during the process of fabricating the magnetic recording medium.Type: GrantFiled: April 25, 2005Date of Patent: April 22, 2008Assignee: Fujitsu LimitedInventors: Yutaka Nakamura, Hitoshi Komoriya, Hiroyuki Suzuki, Takao Hirahara, Arata Ejiri
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Publication number: 20070297078Abstract: The present invention provides a magnetic transfer method comprising: a magnetic transfer step of applying a magnetic field for transfer parallel to the plane of a disk shaped substrate having formed on the surface thereof a pattern composed of magnetic layer arrangement corresponding to information to be transferred to a perpendicular magnetic recording medium while a master recording medium for perpendicular magnetic transfer being the substrate is brought into close contact with the perpendicular magnetic recording medium, and thereby transferring the magnetic pattern of the master recording medium for perpendicular magnetic transfer to the perpendicular magnetic recording medium; and a servo correction information writing step of writing by use of a magnetic head, servo correction signal information into a section adjacent to the information transferred to the perpendicular magnetic recording medium by the magnetic transfer step.Type: ApplicationFiled: June 18, 2007Publication date: December 27, 2007Applicant: FUJIFILM CORPORATIONInventors: Makoto NAGAO, Toshihide ISHIOKA
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Publication number: 20070297077Abstract: The present invention provides a method of manufacturing a master recording medium used for magnetic transfer and having a concavo-convex pattern formed on a surface of the recording medium, the method comprising: a surface treatment step of forming the concavo-convex pattern on a surface of a metal plate to fabricate a metal master disk; a monomolecular layer forming step of forming a monomolecular layer on a surface of the metal master disk, the surface having the concavo-convex pattern formed thereon; a metallic substrate forming step of dipping the metal master disk having the monomolecular layer formed thereon into a plating solution and forming the master recording medium by plating on the surface of the metal master disk, the surface having the monomolecular layer formed thereon; and an exfoliating step of exfoliating the master recording medium from the metal master disk.Type: ApplicationFiled: June 18, 2007Publication date: December 27, 2007Applicant: FUJIFILM CORPORATIONInventors: Yanlong CHE, Toshiya Takahashi
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Patent number: 7312940Abstract: A magnetic transfer apparatus is provided with a transfer holder. A master information carrier and a slave medium are accommodated in the transfer holder in an overlapping state where they are opposed to each other and held in close contact with each other. The master information carrier and the slave medium overlapping each other are pressed against each other by hermetically closing the holder and evacuating the inner space of the holder.Type: GrantFiled: January 21, 2004Date of Patent: December 25, 2007Assignee: Fujifilm CorporationInventor: Akito Kamatani
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Publication number: 20070291387Abstract: A magnetic transfer method comprises the processes of: adhering a side having a perpendicular magnetic recording layer of a perpendicular magnetic recording medium in which a perpendicular magnetic recording layer is formed on a surface of a disk shaped substrate, to a surface of a master recording medium in which a magnetic layer is formed corresponding to information to be recorded for transferring information to the perpendicular magnetic recording medium and of the side having the magnetic layer formed; and performing magnetic transfer by relatively rotating a magnetic field application device about the center of the perpendicular magnetic recording medium as an axis with respect to the perpendicular magnetic recording medium and the master recording medium, while applying a magnetic field to the perpendicular magnetic recording medium and the master recording medium by the magnetic field application device, wherein the magnetic field application device is rotated two or more times.Type: ApplicationFiled: June 11, 2007Publication date: December 20, 2007Applicant: FUJIFILM CorporationInventors: Makoto NAGAO, Naoto FUJIWARA
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Patent number: 7301714Abstract: A magnetic pattern, in which errors due to sub-pulses do not occur during signal reproduction, is transferred from a magnetic transfer master carrier. A magnetic field is applied to a conjoined body, formed by the master carrier bearing a transfer pattern corresponding to desired information and a discoid transfer medium. A magnetic transfer apparatus that includes magnetic field applying means having magnetic poles that extend from the interior to the outer periphery of the conjoined body, and rotating means for relatively rotating the conjoined body with respect to the magnetic poles is employed. The magnetic poles are provided such that a distance d, between end surfaces of the magnetic poles and the conjoined body decrease from the interior to the outer periphery of the conjoined body. Magnetic transfer is performed employing the magnetic field, the intensity of which increases from the interior to the outer periphery of the transfer medium.Type: GrantFiled: March 24, 2005Date of Patent: November 27, 2007Assignee: FUJIFILM CorporationInventor: Masakazu Nishikawa
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Patent number: 7296478Abstract: In a master carrier for magnetic transfer which comprises a support that has a transfer-recording pattern arrayed in the track direction thereof in accordance with the information to be transferred to a magnetic recording medium, and a magnetic layer formed on the transfer-recording pattern of the support, the in-plane distance L (mm) between the hill and the valley of the warped master carrier, the vertical-direction distance H (?m) between the two, and the thickness d (mm) of the master carrier are so defined that they satisfy a relation of 0.05?H·d3/L?0.6.Type: GrantFiled: March 3, 2006Date of Patent: November 20, 2007Assignee: Fujifilm CorporationInventors: Masakazu Nishikawa, Naoto Fujiwara
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Publication number: 20070247734Abstract: When copying servo information from an electro-magnetic field copy master to a vertical storage medium, the magnetization direction of the vertical storage medium is made to the direction the reverse of an external electro-magnetic field applied to the vertical storage medium and the electro-magnetic field copymaster, the vertical storage medium is closely touched on the electromagnetic field copy master provided with a substrate which has concavity/convexity corresponding to the servo information and at least the convex part of which of the concavity/convexity is made of a softly magnetic material and a conductor installed in the concave part of the substrate and an external electro-magnetic field stronger than the coercive field strength of the vertical storage medium is instantaneously applied to the vertical storage medium and the electromagnetic field copy master.Type: ApplicationFiled: August 21, 2006Publication date: October 25, 2007Inventor: Sumio Kuroda
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Publication number: 20070177291Abstract: The present invention provides a method of initializing a perpendicular magnetic recording medium in which a magnetic field having a magnetic field strength Hex is applied to a perpendicular magnetic recording medium having a magnetic layer having a coercive force Hc to initialize the magnetic layer, the method comprising the steps of: controlling a magnetic field strength HexP in a direction parallel to the medium surface of the magnetic field so that HexP>1.3×Hc; and controlling a magnetic field strength HexV in a direction perpendicular to the medium surface of the magnetic field so that HexV<Hc.Type: ApplicationFiled: January 30, 2007Publication date: August 2, 2007Applicant: FUJIFILM CorporationInventors: Satoshi Wakamatsu, Makoto Nagao, Toshihide Ishioka, Atsushi Morooka
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Patent number: 7218466Abstract: An apparatus for performing contact printing of a magnetic transition pattern in a magnetic recording medium, comprising: (a) a stamper/imprinter including a body formed of at least one magnetic material having a high saturation magnetization Bsat and a high permeability, including an imprinting surface adapted to be placed in intimate contact with a surface of a magnetic layer, the imprinting surface comprised of a plurality of patterned areas which separate a plurality of areas which are not patterned, each of the areas which is not patterned being provided with at least one of: (i) mechanical reinforcing means for preventing deformation of the body when the imprinting surface is urged into contact with the surface of the magnetic layer; and (ii) gas venting means for facilitating removal of air or other gas from between the imprinting surface and the surface of the magnetic layer when the former is urged into contact with the latter.Type: GrantFiled: June 4, 2003Date of Patent: May 15, 2007Assignee: Seagate Technology LLCInventors: Neil Deeman, Joseph Leigh, Koichi Wago, Li-Ping Wang
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Patent number: 7218465Abstract: A stamper/imprinter for use in forming a magnetic transition pattern in a magnetic material by means of contact printing, comprising: (a) a non-magnetic substrate having a major surface comprising a patterned plurality of spaced-apart recesses with a plurality of non-recessed areas therebetween, the patterned plurality of recesses corresponding to the magnetic transition pattern to be formed in the magnetic material; and (b) unidirectionally permanently magnetized material filling each of the plurality of recesses and having exposed surfaces substantially coplanar with the plurality of non-recessed areas.Type: GrantFiled: June 4, 2003Date of Patent: May 15, 2007Assignee: Seagate Technology LLCInventors: Neil Deeman, Shih-Fu Lee
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Patent number: 7203014Abstract: The magnetic recording and reproducing apparatus reads a transfer clock synchronized with servo information and records a write-once clock pattern in a state where 0 is set as a delay time of the delay device 13 and 1 is set as the dividing ratio of the frequency divider 17. The apparatus corrects the delay time according to the output of the phase comparator 14 which changes on the basis of the phase difference and rewrites a write-once clock pattern. Rotation of the magnetic disk, detection of the phase difference and correction of the delay time are repeatedly preformed until no change occurs in the output of the phase comparator 14. After the output stops changing, preformat information patterns excluding the servo information pattern are recorded as fine patterns by changing the dividing ratio of the frequency divider 17 to multiply the frequency.Type: GrantFiled: August 1, 2003Date of Patent: April 10, 2007Assignee: Fujitsu LimitedInventors: Sumio Kuroda, Kazuyuki Ozaki
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Patent number: 7199953Abstract: A favorable magnetic transfer is performed to a perpendicular magnetic recording medium. A master medium is provided with a substrate on the surface of which protrusion portions, which form a pattern corresponding to the data that is to be transferred, having a pliable layer thereon have been formed. The master medium is further provided with a soft magnetic layer formed in the depression portions between the protrusion portions, and which is magnetically linked to the soft magnetic layer of the protrusion portions. The soft magnetic layer of the surface of the protrusion portions is conjoined with the magnetic recording layer of a perpendicular magnetic recording medium to form a conjoined body, and a transfer magnetic field is applied to the conjoined body in the direction from the substrate of the master medium toward the slave medium to perform the magnetic transfer.Type: GrantFiled: May 12, 2004Date of Patent: April 3, 2007Assignee: Fujifilm CorporationInventors: Masakazu Nishikawa, Kazunori Komatsu
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Patent number: 7193796Abstract: A patterned master carrier for magnetic transfer is used to transfer a magnetization pattern, which does not cause a problem such as an error attributable to a subpulse upon signal reproduction, to a slave medium. A signal pattern on a surface of a patterned master carrier for the magnetic transfer includes signal areas and no-signal areas, and the signal area is provided with an actual signal pattern and a dummy signal pattern adjacent to the no-signal area. Therefore, the actual signal pattern is not adjacent to the no-signal area.Type: GrantFiled: June 25, 2004Date of Patent: March 20, 2007Assignee: Fuji Photo Film Co., Ltd.Inventor: Tadashi Yasunaga
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Patent number: 7190538Abstract: In a master carrier for magnetic transfer which comprises a support that has a transfer-recording pattern arrayed in the track direction thereof in accordance with the information to be transferred to a magnetic recording medium, and a magnetic layer formed on the transfer-recording pattern of the support, the in-plane distance L (mm) between the hill and the valley of the warped master carrier, the vertical-direction distance H (?m) between the two, and the thickness d (mm) of the master carrier are so defined that they satisfy a relation of 0.05?H·d3/L?0.6.Type: GrantFiled: March 3, 2006Date of Patent: March 13, 2007Assignee: Fuji Photo Film Co., Ltd.Inventors: Masakazu Nishikawa, Naoto Fujiwara
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Patent number: 7187510Abstract: A signal such as a servo tracking signal is recorded on a flexible slave medium by magnetic transfer. When forming the flexible slave medium of a magnetic strip in a continuous length, the signal is recorded on the magnetic strip by patterned master magnetic transfer prior to or simultaneously with shaping the magnetic strip into a desired shape.Type: GrantFiled: December 19, 2002Date of Patent: March 6, 2007Assignee: Fuji Photo Film Co., Ltd.Inventors: Tadashi Yasunaga, Kazuhiro Niitsuma
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Patent number: 7170699Abstract: A master disk has an aspect ratio of a width of a groove to a depth thereof to facilitate embedding of a soft magnetic film in the groove for stabilizing magnetic printability. The master disk has at least two differently shaped grooves, in each of which the width of the groove is equal to the width in the sector direction of a servo pattern and the depth is varied. A servo pattern has a width equal to a width of the groove in the sector direction, with the depth of the groove being proportional to the servo pattern width. At least two depths of grooves are provided for embedding magnetic materials on a substrate of the master disk. The depth of the groove for embedding the soft magnetic film is made shallow in a region where the pattern width of the servo pattern is narrow and made deep in a region where the pattern width is wide.Type: GrantFiled: March 1, 2004Date of Patent: January 30, 2007Assignee: Fuji Electric Holdings Co., Ltd.Inventor: Hiroyuki Yoshimura
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Patent number: 7170698Abstract: Disclosed is a magnetic transfer apparatus capable of performing good magnetic transfer, including a holder for accommodating a master carrier with transfer patterns corresponding to transfer information, a slave-feeding unit for feeding a slave medium with a magnetic recording part to be transferred to the master carrier, and a magnetic field application unit for applying a magnetic field in a state that the slave medium is in close contact with the master carrier, wherein the holder is provided with a slave holding shaft for positioning a central opening of the slave medium at a central portion thereof, and an inner diameter of the central opening of the slave medium is set to be smaller than that of a central opening the master carrier, and the slave-feeding unit holds an inner diameter portion of the slave medium.Type: GrantFiled: February 14, 2003Date of Patent: January 30, 2007Assignee: Fuji Photo Film Co. Ltd.Inventor: Akito Kamatani
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Patent number: 7151641Abstract: A favorable magnetic transfer is performed to a perpendicular magnetic recording medium. A master medium is provided with a substrate on the surface of which protrusion portions, which form a pattern corresponding to the data that is to be transferred, having a pliable layer thereon have been formed. The master medium is further provided with a soft magnetic layer formed in the depression portions between the protrusion portions, and which is magnetically linked to the soft magnetic layer of the protrusion portions. The soft magnetic layer of the surface of the protrusion portions is conjoined with the magnetic recording layer of a perpendicular magnetic recording medium to form a conjoined body, and a transfer magnetic field is applied to the conjoined body in the direction from the substrate of the master medium toward the slave medium to perform the magnetic transfer.Type: GrantFiled: May 12, 2004Date of Patent: December 19, 2006Assignee: Fuij Photo Film Co., Ltd.Inventors: Masakazu Nishikawa, Kazunori Komatsu
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Patent number: 7149042Abstract: A master carrier for magnetic transfer is equipped with a substrate having a land/groove pattern. The land/groove pattern is formed from a magnetic material and corresponds to information that is transferred to a magnetic recording disk. Each land in the land/groove pattern has four round corners whose radius is from 1% through 47% of the width of a data track on the disk.Type: GrantFiled: December 20, 2004Date of Patent: December 12, 2006Assignee: Fuji Photo Film Co., Ltd.Inventors: Masakazu Nishikawa, Tadashi Yasunaga, Kazuhiro Niitsuma
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Patent number: 7139140Abstract: When executing a magnetic transfer by bringing a master medium and a slave medium into close contact with each other and applying a transferring magnetic field, a permitted limit of the application direction of the transferring magnetic field is defined so that magnetic patterns can be accurately transferred. A slave medium 2 is previously initial DC magnetized in a track direction by applying a magnetic field to the slave medium in the track direction of a slave surface, and when executing a magnetic transfer by bringing the master medium 3 and the slave medium 2 into close contact with each other and applying the transferring magnetic field in the track direction of the slave surface, the application angle ? of the transferring magnetic field is defined within a range of ±30° in a vertical direction with respect to the slave surface.Type: GrantFiled: February 21, 2002Date of Patent: November 21, 2006Assignee: Fuji Photo Film Co., Ltd.Inventors: Kazunori Komatsu, Masakazu Nishikawa
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Patent number: 7126783Abstract: A disk drive apparatus that performs a positioning of a head based on servo information recorded on a recording medium includes a servo control unit that performs a servo control based on a set of pieces of servo information selected from a plurality of sets of pieces of servo information recorded on the recording medium.Type: GrantFiled: June 20, 2005Date of Patent: October 24, 2006Assignee: Fujitsu LimitedInventors: Hiroyuki Suzuki, Arata Ejiri
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Patent number: 7119973Abstract: A magnetic transfer apparatus magnetically transfers information carried by a master information carrier to a slave medium held in close contact with the master information carrier by a holder disposed on the holder support portion of a magnetic transfer apparatus. The holder is formed by a pair of halves movable toward and away from each other, and a transfer magnetic field is applied to the master information carrier and the slave medium held in close contact with each other by the holder. A locator mechanism is provided between the holder support portion and the holder and locates the holder at least in a direction perpendicular to the central axis of the holder.Type: GrantFiled: November 19, 2003Date of Patent: October 10, 2006Assignee: Fuji Photo Film Co., Ltd.Inventor: Akito Kamatani
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Patent number: 7110201Abstract: A master medium is utilized in a magnetic transfer apparatus. The master medium is superposed on a blank magnetic medium. A predetermined magnetic field is then applied to the master medium. The magnetic flux leaks from the master medium between adjacent magnetic pieces on the master medium. The leaked magnetic flux acts on the magnetic medium. The magnetization is accordingly established on the surface of the magnetic medium. Here, spaces can be reduced between the adjacent magnetic pieces on the master medium. Magnetization of a sufficient intensity can reliably be established on the magnetic medium.Type: GrantFiled: June 17, 2004Date of Patent: September 19, 2006Assignee: Fujitsu LimitedInventors: Hiroyuki Suzuki, Hitoshi Komoriya, Yutaka Nakamura
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Patent number: 7110196Abstract: A favorable magnetic transfer is performed on a vertical magnetic recording medium. A permanent magnet apparatus employs a transfer magnetic field generating means provided with two columnar permanentmagnets, each having a cross-sectional surface are equal to or greater than that of the track surface of the slave medium. A conjoined body formed of a slave medium, which has been initially magnetized unidirectionally in the direction perpendicular to the track surface thereof, and two master mediums, disposed on respective surfaces of the slave medium, is inserted between the permanent magnets so that a transfer magnetic field can be applied thereto in the direction substantially opposite that in which the initial magnetization has been performed. A uniform transfer magnetic field is applied over the entirety of track surface of the slave medium so as to simultaneously perform a magnetic transfer over the entirety of the track surface.Type: GrantFiled: May 17, 2002Date of Patent: September 19, 2006Assignee: Fuji Photo Film Co., Ltd.Inventors: Kazunori Komatsu, Masakazu Nishikawa
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Patent number: 7106531Abstract: A contact magnetic transfer (CMT) method for forming a magnetic pattern, such as the servo pattern on a magnetic recording disk, uses a master template with antiferromagnetically-coupled (AF-coupled) magnetic islands. The template is a rigid or flexible substrate with each magnetic island being two ferromagnetic films antiferromagnetically-coupled by an antiferromagnetically-coupling (AFC) film. In the presence of the applied magnetic field the magnetic moments of the two ferromagnetic films are parallel and substantially identical so they generate a magnetic field that cancels the applied field in the region of the slave disk facing the islands. However, when the applied field is removed, any residual magnetization results in the remanent moments in the two ferromagnetic films being oriented antiparallel as a result of the antiferromagnetic exchange coupling across the AFC film. Thus the islands have no net remanent magnetic moment that can affect the servo pattern transferred to the recording disk.Type: GrantFiled: January 13, 2005Date of Patent: September 12, 2006Assignee: Hitachi Global Storage Technologies Netherlands, B.V.Inventors: Zvonimir Z. Bandic, Ernesto E. Marinero
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Patent number: 7099094Abstract: A method for manufacturing a master used for a magnetic transfer, the method including the following steps: A first-master manufacturing step of manufacturing a first master including a predetermined magnetic pattern based on magnetic information; a magnetic-pattern transferring step of transferring the magnetic pattern to a magnetic recording medium by using the first master; an error confirming step of confirming an amount of a transfer error between the magnetic pattern transferred to the magnetic recording medium and the predetermined magnetic pattern; and a second-master manufacturing step of manufacturing a second master as an authentic master based on a correction magnetic pattern so formed as to offset the amount of the transfer error.Type: GrantFiled: July 11, 2005Date of Patent: August 29, 2006Assignee: Fujitsu LimitedInventors: Yutaka Nakamura, Hitoshi Komoriya, Hiroyuki Suzuki, Takao Hirahara
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Patent number: 7094481Abstract: A master information carrier for magnetic transfer to an in-plane magnetic recording medium includes a base sheet having an irregularity pattern representing information to be transferred to an in-plane magnetic recording medium and a magnetic layer formed along the irregularity pattern. The thickness da1 of the magnetic layer on the upper surface of a protruding portion of the irregularity pattern and the thickness da2 of the magnetic layer on each of the side surfaces of the protruding portion satisfy the following condition, 0.05<da2/da1?1.3.Type: GrantFiled: October 6, 2004Date of Patent: August 22, 2006Assignee: Fuji Photo Film Co., Ltd.Inventors: Masakazu Nishikawa, Kazuhiro Niitsuma, Tadashi Yasunaga, Toshihiro Usa, Kazunori Komatsu
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Patent number: 7094484Abstract: In a master carrier for magnetic transfer which comprises a support that has a transfer-recording pattern arrayed in the track direction thereof in accordance with the information to be transferred to a magnetic recording medium, and a magnetic layer formed on the transfer-recording pattern of the support, the in-plane distance L (mm) between the hill and the valley of the warped master carrier, the vertical-direction distance H (?m) between the two, and the thickness d (mm) of the master carrier are so defined that they satisfy a relation of 0.05?H·d3/L?0.6.Type: GrantFiled: July 20, 2004Date of Patent: August 22, 2006Assignee: Fuji Photo Film Co., Ltd.Inventors: Masakazu Nishikawa, Naoto Fujiwara
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Patent number: 7089353Abstract: A method for writing a servopattern comprises writing a first burst at a first radial position, writing a second burst at a second radial position, wherein an edge of the first burst and an edge of the second burst have a substantially similar common radial position, and defining a portion of the edge of the first burst on a different revolution than defining a portion of the edge of the second burst.Type: GrantFiled: December 18, 2002Date of Patent: August 8, 2006Assignee: Hitachi Global Technologies Netherlands, B.V.Inventors: Timothy J. Chainer, Mantle Man-Hon Yu
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Patent number: 7079335Abstract: A favorable magnetic transfer is, performed on a perpendicular magnetic recording medium. A permanent magnet apparatus provided with two permanent magnets, each having a width extending the length of the radial direction of a discoid magnetic recording medium, is used as a transfer magnetic field generating means. A conjoined body formed of the perpendicular magnetic recording medium, which has been initially magnetized unidirectionally in the direction perpendicular to the track surface thereof, and two master mediums, disposed on respective surfaces of the slave medium, is inserted between the permanent magnets. A rotating means rotates the conjoined body, in the direction along the tracks of the slave medium, while a transfer magnetic field is applied to the conjoined body in the direction substantially opposite that in which the initial magnetization of the magnetic layer of magnetic recording medium has been performed, so as to perform the magnetic transfer.Type: GrantFiled: April 20, 2005Date of Patent: July 18, 2006Assignee: Fuji Photo Film Co., Ltd.Inventors: Kazunori Komatsu, Masakazu Nishikawa
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Patent number: 7079336Abstract: A magnetic transfer wherein the exchange of master mediums is made easy to perform is provided, whereby the operational efficiency and transfer efficiency are improved, leading to an overall improvement in productivity in the manufacture of preformatted slave mediums. A master fixing base for determining and supporting the position of a master medium, which bears transfer data, and a conjoining apparatus for conjoining the master medium and the slave medium that is to receive the transfer therefrom are provided. The master medium is exchanged along with the master fixing base. It is preferable that a cleaning means be provided.Type: GrantFiled: May 12, 2005Date of Patent: July 18, 2006Assignee: Fuji Photo Film Co., Ltd.Inventors: Akito Kamatani, Tsuneo Inui, Masashi Aoki, Masakazu Nishikawa
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Patent number: 7061702Abstract: To enable alignment of a magnetic pattern of a pair of master disks and a magnetic recording medium, each of the master disks has at least a pair of alignment marks disposed outside the region of the magnetic pattern. The master disks can be optically transparent or semi-transparent. The master disks can be aligned while the alignment marks are externally observed.Type: GrantFiled: November 17, 2003Date of Patent: June 13, 2006Inventors: Hiroyuki Yoshimura, Kiminori Sato
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Patent number: 7061703Abstract: A master information carrier capable of manufacturing a magnetic recording medium in which a preformat recording of information signals causing no reproduction signal detection errors arising from a pulse shift of a reproduction waveform is performed. A master information carrier 1 has an array of ferromagnetic thin films 3 arranged according to the pattern of information signals and is used for forming magnetization 4 of a pattern corresponding to the array pattern of the ferromagnetic thin film 3 in a magnetic recording medium by applying a magnetic field while opposing the master information carrier 1 against a magnetic recording medium 2. Each of the ferromagnetic thin films 3 is formed such that each pattern length A becomes equal to a length including a correction amount ? in addition to a length a between magnetic transition areas 6 of the magnetization 4 to be formed in the magnetic recording medium 2.Type: GrantFiled: October 14, 2003Date of Patent: June 13, 2006Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Tatsuaki Ishida, Keizo Miyata, Nobuyuki Komura, Yasuaki Ban, Taizou Hamada, Hideyuki Hashi
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Patent number: 7057834Abstract: A master information carrier capable of manufacturing a magnetic recording medium in which a preformat recording of information signals causing no reproduction signal detection errors arising from a pulse shift of a reproduction waveform is performed. A master information carrier 1 has an array of ferromagnetic thin films 3 arranged according to the pattern of information signals and is used for forming magnetization 4 of a pattern corresponding to the array pattern of the ferromagnetic thin film 3 in a magnetic recording medium by applying a magnetic field while opposing the master information carrier 1 against a magnetic recording medium 2. Each of the ferromagnetic thin films 3 is formed such that each pattern length A becomes equal to a length including a correction amount ? in addition to a length a between magnetic transition areas 6 of the magnetization 4 to be formed in the magnetic recording medium 2.Type: GrantFiled: March 29, 2001Date of Patent: June 6, 2006Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Tatsuaki Ishida, Keizo Miyata, Nobuyuki Komura, Yasuaki Ban, Taizou Hamada, Hideyuki Hashi
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Patent number: 7054081Abstract: By bring a master carrier and a slave medium into close contact with uniform force when executing magnetic transfer by applying transfer magnetic field in the state that the master carrier and slave medium is in confronted close contact and received within a holder, inferiority of transfer such as omission of signals is prevented and quality of transfer signals is enhanced. The magnetic transfer apparatus executes magnetic transfer by applying transfer magnetic field by means of a magnetic field applying apparatus 5 after a master carrier 3, 4 bearing transfer information and a slave medium 2 to be transferred are brought into confronted close contact and received within a holder 10, wherein said holder 10 has a substantially circular shape and in particular, the circularity of holder is not less than 98%, wherein the flexural rigidity=Ed3/12 determined by Young's modulus E and thickness d of the holder is in the range of 0.Type: GrantFiled: May 5, 2005Date of Patent: May 30, 2006Assignee: Fuji Photo Film Co., Ltd.Inventors: Masakazu Nishikawa, Kazuhiro Niitsuma, Akito Kamatani
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Patent number: 7054080Abstract: By bring a master carrier and a slave medium into close contact with uniform force when executing magnetic transfer by applying transfer magnetic field in the state that the master carrier and slave medium is in confronted close contact and received within a holder, inferiority of transfer such as omission of signals is prevented and quality of transfer signals is enhanced. The magnetic transfer apparatus executes magnetic transfer by applying transfer magnetic field by means of a magnetic field applying apparatus 5 after a master carrier 3, 4 bearing transfer information and a slave medium 2 to be transferred are brought into confronted close contact and received within a holder 10, wherein said holder 10 has a substantially circular shape and in particular, the circularity of holder is not less than 98%, wherein the flexural rigidity=Ed3/12 determined by Young's modulus E and thickness d of the holder is in the range of 0.Type: GrantFiled: May 5, 2005Date of Patent: May 30, 2006Assignee: Fuji Photo Film Co., Ltd.Inventors: Masakazu Nishikawa, Kazuhiro Niitsuma, Akito Kamatani