Fuji Photo Film Company, Limited

Fujifilm Corporation

Fuij Photo Film Co., Ltd.

Masakazu Nishikawa

Kazunori Komatsu

Makoto Nagao

Kazuhiro Niitsuma

Tadashi Yasunaga

Akito Kamatani

Masashi Aoki

Kazuyuki Usuki

Tsuneo Inui

Seiichi Watanabe

Toshihiro Usa

Naoto Fujiwara

Ryuji Sugita

Junichi Nakamikawa

Hideyuki Kubota

Yoshihisa Usami

Seiji Kasahara

Takako Ozawa

Takashi Komine

Yoichi Nishida

Kenichi Moriwaki

The present invention provides a magnetic transfer master carrier which forms a magnetic pattern corresponding to a pattern of information to be recorded on a perpendicular magnetic recording medium when a magnetic field is applied to the perpendicular magnetic recording medium, with the magnetic master carrier and the perpendicular magnetic recording medium closely attached to each other, the carrier including: a base material having convex portions on its surface, the convex portions being provided corresponding to the pattern of information; a magnetic layer deposited on at least top surfaces of the convex portions, and having perpendicular magnetic anisotropy; and a soft magnetic layer deposited on the surface of the magnetic layer.

Magnetic transfer master carrier, magnetic transfer method, and magnetic recording medium

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.

Method of magnetic transfer and stopping slave medium rotation

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.

Master information carrier for magnetic transfer

A master information carrier for magnetic transfer includes a master substrate made of metal, including an embossed pattern corresponding to information to be transferred. The master substrate is produced by laminating a metal disk with a predetermined thickness on an original disk, on which an embossed pattern is formed, by electroforming, peeling off the metal disk and die-cutting a disk in a desired size. An outer diameter of the metal disk is at least 1.7 times longer than an outer diameter of the die-cut master substrate. When the metal disk is peeled off from the original disk, deformation due to the forces acting from the side of the outer circumference is reduced. The flatness of the metal disk is ensured and the transfer qualities are improved. Further, a step of removing distortion of the metal disk, caused at the time of peeling off the metal disk, may also be provided.

Master information carrier for magnetic transfer and its production method

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.

Method and apparatus for magnetic transfer

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 B, dummy uneven patterns are provided in a depression of the uneven signal patterns, which has a length of 4Bor 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.

Master information carrier for magnetic transfer, magnetic transfer method, and magnetic recording medium

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 apparatusafter a master carrierbearing transfer information and a slave mediumto be transferred are brought into confronted close contact and received within a holder, wherein said holderhas a substantially circular shape and in particular, the circularity of holder is not less than 98%, wherein the flexural rigidity=Ed/12 determined by Young's modulus E and thickness d of the holder is in the range of 0.1&#x2dc;30 kN&#xb7;mwhen the width of close contact area between the slave medium and master carrier is defined as 1 m, and wherein the practical thickness of the holder is not less than 3 mm and not more than 15 mm.

Magnetic transfer apparatus

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.

Master carrier for magnetic transfer

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.

Method and apparatus for magnetic transfer, and magnetic recording medium

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 (&#x3bc;m) between the two, and the thickness d (mm) of the master carrier are so defined that they satisfy a relation of 0.05&#x2266;H&#xb7;d/L&#x2266;0.6.

Master carrier for magnetic transfer, inspecting method thereof, and magnetic recording medium producing method

A process for producing a master carrier contains steps of: forming a desired pattern on a support to form a resist pattern support; forming a first ferromagnetic thin film on the resist pattern support by a vacuum film forming method; forming a third ferromagnetic thick film on the first ferromagnetic thin film by an electroplating; and peeling the support from the resist pattern support provided with the first ferromagnetic thin film and the third ferromagnetic thick film.

Process of producing master carrier for magnetic transfer

A magnetic transfer method for transferring a magnetic recording information on a master carrier for magnetic transfer to a slave medium by bringing the master carrier for magnetic transfer with a magnetic layer with magnetic recording information recorded thereon into close contact with the slave medium where the information is to be transferred, whereby initial DC magnetization is performed on the slave medium in advance in track direction, and using a magnetic material having a product (Ms&#xb7;&#x3b4;) of saturation magnetization (Ms) and magnetic layer thickness (&#x3b4;) within the range of 0.025 T&#xb7;&#x3bc;m (20 G&#xb7;&#x3bc;m)&#x2013;2.3 T&#xb7;&#x3bc;m (1830 G&#xb7;&#x3bc;m) inclusive as the master carrier for magnetic transfer, the slave medium after the initial DC magnetization is brought into close contact with the master carrier, and a magnetic field for transfer is applied in a direction opposite to the direction of the initial DC magnetization of the slave surface, and magnetic transfer is performed.

Magnetic transfer method

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.

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Kanagawa-ken, Japan

Masakazu Nishikawa