JP2006147059A - Magnetic transfer device and magnetic transfer method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic transfer device and a magnetic transfer method which can perform a successful magnetic transfer suppressing the disturbance of a magnetization pattern over a whole area from an innermost peripheral track to an outermost peripheral track even in a magnetic disk downsized in diameter. <P>SOLUTION: When the diameter of a disk to be transferred is ≤40 mm, a half-value width of a curve is prescribed to be ≤125% diameter of the innermost peripheral track, which shows a strength distribution of the tangential direction of a track on an innermost peripheral track of the surface of the disk to be transferred, for an initial DC magnetic field impressed by an initial magnetizing means and a transfer magnetic field impressed by a transfer magnetic field impressing means. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a magnetic transfer apparatus and a magnetic transfer method, and more particularly, to a magnetic transfer apparatus for magnetically transferring information from a master disk on which information to be transferred is formed in a pattern to a magnetic disk for transfer, which is a magnetic recording medium, and The present invention relates to a magnetic transfer method.

  Magnetic disks, which are high-density magnetic recording media used in hard disk devices, flexible disk devices, and the like, are capable of high-speed access and are required to have a larger information recording capacity.

  In order to realize this large capacity, the track width is narrowed, and so-called tracking servo technology for accurately scanning the magnetic head within this narrow track width plays an important role.

  On the magnetic disk, a tracking servo signal, an address information signal, a reproduction clock signal, and the like are recorded at a predetermined interval as a preformat for performing tracking servo.

  As a method of accurately and efficiently performing this preformatting in a short period of time, the applicant of the present application has used unevenness corresponding to information to be transferred to a transfer target disk (hereinafter referred to as a slave disk) serving as a high-density magnetic recording medium. A master disk having a patterned magnetic layer is prepared, and the magnetic layer of the slave disk is preliminarily magnetized in one direction of the track in advance, and then the initial magnetization is performed with the slave disk and master disk in close contact with each other. A magnetic transfer method has been proposed in which a transfer magnetic field substantially opposite to the direction is applied (see, for example, Patent Document 1).

  This initial DC magnetic field and transfer magnetic field application method generates a magnetic field in a direction along the tangential direction of the track in one area of all tracks, and rotates the slave disk relative to the magnetic field to thereby apply all the tracks on all tracks. Apply a magnetic field to the region.

  However, when a magnetic field is applied in the tangential direction of the track, the magnetic field actually has a certain extent with respect to the tangential direction of the track. For this reason, the magnetic field in the direction deviating from the track direction is received at a position deviated from the track contact position, and if the intensity of the magnetic field in the direction deviating from the track direction is large, the initial magnetization or transfer magnetization pattern of the slave disk is disturbed, There was a problem that high-precision magnetization transfer could not be performed.

  In order to solve this problem, the present applicant has determined that the initial DC magnetic field and the transfer magnetic field in which the half width of the curve indicating the tangential intensity distribution in the innermost track on the surface of the slave disk is equal to or smaller than the diameter of the innermost track. Has been proposed (see, for example, Patent Document 2).

  In this case, the optimum strength of the initial DC magnetic field applied for initial magnetization of the magnetic layer of the slave disk is not less than the coercive force Hc of the magnetic layer of the slave disk, preferably not less than 1.2 times the coercive force Hc, and more preferably. It is about twice or more of the coercive force Hc. The optimum strength of the magnetic field for transfer was about 0.6 to 1.3 times the coercive force Hc of the magnetic layer of the slave disk.

By defining the spread of the intensity distribution of the magnetic field as described above, it is possible to perform good magnetic transfer while suppressing the disturbance of the magnetization pattern in the entire region from the innermost track to the outermost track.
JP 2001-014667 A JP 2003-303413 A

  By the way, the magnetic disk, which is a magnetic recording medium, has not only been increased in density but also reduced in size, and the diameter of the innermost track of the slave disk has been reduced accordingly. For this reason, as specified in the above-mentioned Patent Document 2, the half width of the intensity distribution curve of the initial DC magnetic field applied for initial magnetization of the magnetic layer of the slave disk and the magnetic pattern of the master disk are set to the magnetic characteristics of the slave disk. In order to make the full width at half maximum of the intensity distribution curve of the transfer magnetic field transferred to the layer equal to or less than the diameter of the innermost track, the applied magnetic field strength must be increased, and therefore the coercive force Hc of the magnetic layer of the slave disk. Various problems have arisen, such as the need to increase the magnetic field, or the magnetic pole of the magnetic field application magnet must be close to the slave disk, and the yield is reduced due to difficulty in manufacturing in the actual manufacturing process. It was.

  The present invention has been made in view of such circumstances, and even in the case of a magnetic disk with a reduced diameter, in the entire region extending from the innermost track to the outermost track, the magnetic pattern is prevented from being disturbed. It is an object of the present invention to provide a magnetic transfer apparatus and a magnetic transfer method capable of performing magnetic transfer.

  In order to achieve the above object, the present invention provides a disk for transfer by rotating the disk for transfer relative to the initial DC magnetic field while applying an initial DC magnetic field to the disk-shaped disk for transfer. An initial magnetization means for initial magnetization of the magnetic layer in one direction of a concentric track, and a master disk having a patterned magnetic layer on the surface for transferring information to the magnetic layer of the disk to be transferred; While the magnetic layer of the initial magnetized disk to be transferred is in close contact with the magnetic field for transfer in the direction opposite to the direction of the initial magnetization, the disk to be transferred and the master disk are integrated with each other. In the magnetic transfer apparatus comprising: a transfer magnetic field applying means for rotating the information relative to the transfer magnetic field to magnetically transfer the information to the magnetic layer of the transfer target disk. And the transfer magnetic field applying means have a half-value width of a curve indicating the intensity distribution in the tangential direction of the track on the innermost track on the surface of the disk to be transferred, and the diameter of the disk to be transferred is 40 mm or less. Is characterized in that the initial DC magnetic field and the transfer magnetic field which are 125% or less of the diameter of the innermost track are applied.

  Further, the magnetic transfer method of the present invention is configured to rotate the disk to be transferred relative to the initial DC magnetic field while applying an initial DC magnetic field to the disk-shaped disk to be transferred. An initial magnetizing means for initial magnetizing a layer in one direction of a concentric track, a master disk having a patterned magnetic layer on the surface for transferring information to the magnetic layer of the disk to be transferred, and the initial disk While the magnetic layer of the magnetized disk to be transferred is in close contact, the transfer disk and the master disk are integrated with each other while applying a transfer magnetic field in a direction opposite to the initial magnetization direction. A magnetic transfer apparatus comprising a transfer magnetic field applying means for rotating the information relative to a magnetic field and magnetically transferring the information to the magnetic layer of the transfer target disk; The half width of the curve indicating the intensity distribution in the tangential direction of the track on the innermost track on the surface of the disk to be transferred, of the initial DC magnetic field to be applied and the transfer magnetic field applied by the transfer magnetic field applying means, When the diameter of the transfer disk is 40 mm or less, the diameter is 125% or less of the diameter of the innermost track.

  According to the present invention, the curve indicating the intensity distribution in the tangential direction of the track in the innermost track on the surface of the disk to be transferred, of the initial DC magnetic field applied by the initial magnetization means and the transfer magnetic field applied by the transfer magnetic field application means. Is set to 125% or less of the diameter of the innermost track when the diameter of the disk to be transferred is 40 mm or less, even if the magnetic disk has a small diameter of 40 mm or less, The intensity of the magnetic field in the direction deviating from the track direction can be kept low, and transfer can be performed with high accuracy.

  As described above, according to the magnetic transfer apparatus and the magnetic transfer method of the present invention, even in a magnetic disk with a reduced diameter, the disturbance of the magnetization pattern is suppressed in the entire region from the innermost track to the outermost track. Excellent magnetic transfer.

  Hereinafter, preferred embodiments of a magnetic transfer apparatus and a magnetic transfer method according to the present invention will be described in detail with reference to the accompanying drawings. In each figure, the same number or symbol is attached to the same member.

  FIG. 1 is a perspective view showing the main part of initial magnetization means for initial magnetization of a slave disk as a transfer disk, FIG. 2 is a plan view for explaining initial magnetization, and FIG. 3 is for explaining initial magnetization. FIG. 3 is a side view (FIG. 3A) and a magnetic field intensity distribution diagram (FIG. 3B).

  The initial magnetization means 20 constituting the magnetic transfer device 10 includes a chuck stage 11 on which the slave disk 2 is mounted and rotated, an electromagnet 20A, and the like. As shown in FIGS. 1 and 2A, the electromagnet 20A has a core 22 having a head that forms a gap 21 extending in the radial direction from at least the innermost track Ta of the slave disk 2 to the outermost track Tb. And a coil 23 wound around the core 22.

  When the coil 23 is energized, a DC magnetic field is generated, the chuck stage 11 rotates in the direction of arrow A shown in FIGS. 1 and 2, and the entire area of the magnetic layers 2b and 2c of the slave disk 2 is magnetized in one direction. It is like that.

  As shown in FIGS. 2A and 3A, the magnetic field Hin is generated in the gap 21 between the heads of the core 22 in the direction along the track direction by the electromagnet 20A. The

  At this time, the magnetic field generated by the electromagnet 20A in the magnetic layer 2b of the slave disk 2 shows a magnetic field strength distribution having a peak at the center of the interval W1 of the gap 21 with respect to the track tangential direction, as shown in FIG. .

  Since this magnetic field intensity spreads in the track tangential direction, the applied magnetic field Hin is a magnetic field in the tangential direction at the point P1 of the track T1, as shown in FIG. At this time, a magnetic field Hin parallel to the track direction is applied at the point P1, but a point deviated from the point P1, for example, a point P2 of the track T2, receives a magnetic field in a direction different from the tangent line S of the point P2. Become. When the magnetic field intensity in a direction deviating from the tangential direction is large, the initial magnetic field is disturbed at that point. This phenomenon becomes more prominent because the radius of curvature is smaller for a track having a smaller diameter.

  Therefore, in the present invention, in order to limit the strength of the magnetic field in the direction deviated from the tangential direction of the track when the initial DC magnetic field is applied, the initial DC magnetic field applied by the initial magnetization means 20 is the maximum on the surface of the slave disk 2. When the slave disk 2 has a diameter of 40 mm or less, the full width at half maximum Win of the curve indicating the intensity distribution in the tangential direction of the track on the inner track Ta is restricted to 125% or less of the diameter 2r of the innermost track Ta. ing.

  When the half-value width Win of the curve indicating the intensity distribution in the tangential direction of the track in the innermost track Ta of the initial DC magnetic field exceeds 125% of the diameter 2r of the innermost track Ta, the magnetic field deviation from the tangential direction of the track Therefore, good initial magnetization cannot be performed.

  In the present invention, by restricting the intensity distribution of the applied magnetic field in this way, in the entire track region from the innermost track Ta to the outermost track Tb, magnetization disturbance is suppressed and good initial magnetization is performed. Can do.

  The initial DC magnetic field Hin is preferably a magnetic field that is about twice or more the coercive force Hc of the magnetic layers 2b and 2c on the upper and lower surfaces of the slave disk 2. Therefore, in the present embodiment, the gap W1 of the gap 21 of the electromagnet 20A is set to a value that is not more than half of the radius r of the innermost track Ta of the slave disk 2, and the distance L1 between the gap 21 and the magnetic layer 2b of the slave disk 2 is It is made to approach to a numerical value of 10 mm or less, preferably 5 mm or less, more preferably 3 mm or less. For example, when the radius r of the innermost track Ta is 4.7 mm, the gap W1 between the gaps 21 is 2.3 mm or less, and the distance L1 between the gap 21 and the magnetic layer 2b of the slave disk 2 is 3 mm or less.

  4 is a perspective view showing a main part of a transfer magnetic field applying means for applying a transfer magnetic field for magnetically transferring information magnetically recorded on the master disk to the slave disk 2, and FIG. 5 explains the transfer magnetic field. FIG. FIG. 5A is a plan view for explaining the direction of the transfer magnetic field, and FIG. 5B is an intensity distribution diagram of the magnetic field.

  The magnetic field applying means 30 for transfer constituting the magnetic transfer apparatus 10 includes a holder 50 that holds the slave disk 2 and the master disk in close contact with each other, electromagnets 30A and 30B disposed on the upper and lower surfaces of the holder 50, and a holder 50 and a rotating means (not shown) that rotates the holder 50 with respect to the electromagnets 30A and 30B in the direction of arrow A in the figure.

  As shown in FIGS. 4 and 5A, the electromagnet 30A includes a core 32 having a head that forms a gap 31 extending in the radial direction from at least the innermost track Ta of the slave disk 2 to the outermost track Tb. And a coil 33 wound around the core 32. The electromagnet 30B has the same configuration.

  When the coil 33 is energized, a DC magnetic field is generated, and a rotating means (not shown) rotates the holder 50 in the direction of arrow A shown in FIGS. 4 and 5 to transfer the master disk information to the entire track area of the slave disk 2. It has become so.

  In the present embodiment, the slave disk 2 is sandwiched between two master disks, and the information of the master disk is transferred to the upper and lower surfaces of the slave disk 2. Therefore, the electromagnet 30A and the electromagnet are formed on the upper and lower surfaces of the holder 50. However, in the case where magnetic information is transferred only to the upper or lower surface of the slave disk 2 using one master disk, only one electromagnet may be disposed on one side of the holder 50.

  As shown in FIG. 5A, the magnetic field Hdu is generated in the direction opposite to the initial magnetization in the gap 31 between the heads of the core 32 by the electromagnet 30A. The

  At this time, as shown in FIG. 5B, the magnetic field generated by the electromagnet 30A in the magnetic layer 2b of the slave disk 2 shows a magnetic field strength distribution having a peak at the center of the gap 31 with respect to the track tangential direction. The same applies to the electromagnet 30B side.

  Since this magnetic field strength spreads in the track tangential direction as in the case of the initial magnetization, a magnetic field in a direction different from the track direction is received at a point deviated from the contact point of the applied magnetic field. If the magnetic field intensity in the direction deviated from the tangential direction is large, the transfer magnetic field is disturbed at that point. This phenomenon becomes more conspicuous because the radius of curvature is smaller in the portion where the track diameter is smaller.

  For this reason, in the present invention, the surface of the slave disk 2 of the transfer magnetic field applied by the transfer magnetic field applying means 30 in order to limit the strength of the magnetic field in the direction deviated from the track tangential direction when the transfer magnetic field is applied. When the diameter of the slave disk 2 is 40 mm or less, the half width Wdu of the curve showing the intensity distribution in the tangential direction of the track on the innermost track Ta is 125% or less of the diameter 2r of the innermost track Ta. It is regulated.

  If the half-value width Wdu of the curve showing the intensity distribution in the tangential direction of the track in the innermost track Ta of the transfer magnetic field exceeds 125% of the diameter 2r of the innermost track Ta, the magnetic field deviation from the tangential direction of the track Is large and good magnetic transfer cannot be performed.

  In the present invention, by restricting the intensity distribution of the applied magnetic field in this way, magnetization disturbance is suppressed in all track regions from the innermost track Ta to the outermost track Tb, and a good magnetization pattern can be transferred. It can be carried out.

  The strength of the transfer magnetic field Hdu is preferably 0.6 times to 1.3 times, more preferably 0.8 times to 1.times the coercive force Hc of the magnetic layers 2b and 2c on the upper and lower surfaces of the slave disk 2. It is 2 times, more preferably 1 to 1.1 times.

  FIG. 6 is an internal exploded perspective view of the holder 50. The holder 50 corrects flatness by sucking and holding the lower holder 51, the lower correction member 53 that sucks and holds the lower master disk 3 and corrects flatness, the upper holder 52, and the upper master disk 4 by suction. The upper straightening member 54 and the like are configured.

  The lower correction member 53 has a disk shape corresponding to the diameter of the master disk 3 and is provided in the lower holder 51. The suction surface 53a for sucking the master disk 3 of the lower correction member 53 has an arithmetic average roughness (Ra ) Is finished to a flatness of 0.01 to 0.1 μm. On the suction surface 53a, 25 to 100 intake holes 53b having a diameter of about 2 mm or less are formed evenly in the surface and connected to a vacuum source (not shown).

  The master disk 3 is sucked and held by the lower correction member 53, and its flatness is corrected following the suction surface 53a of the lower correction member 53. A similar upper correction member 54 is also provided in the upper holder 52, and the master disk 4 is sucked and held to correct the flatness.

  A positioning pin 51b is provided at the center inside the lower holder 51, and engages with the central hole of the slave disk 2 to position the slave disk 2.

  In the slave disk 2, the lower magnetic layer 2c and the upper magnetic layer 3b of the master disk 3 are in close contact with each other, and the upper magnetic layer 2b and the lower magnetic layer 4b of the master disk 4 are in close contact with each other. It is sandwiched between the holder 51 and the upper holder 52. In this state, a magnetic field for transfer is applied to the slave disk 2 from both the upper and lower surfaces of the holder 50, and magnetic information such as servo signals of the master disks 3 and 4 is transferred to the upper and lower surfaces of the slave disk 2.

  Next, a magnetic transfer method using the magnetic transfer apparatus 10 according to the present invention having the aforementioned initial magnetization means 20 and transfer magnetic field applying means 30 will be described.

  FIG. 7 is an explanatory diagram showing the magnetic transfer process of the magnetic transfer method according to the present invention. In FIG. 7, the upper magnetic layer 2b of the slave disk 2 is omitted, and only the transfer to the lower magnetic layer 2c is described to simplify the drawing.

  First, as shown in FIG. 7A, initial magnetization of the slave disk 2 is performed. As shown in FIG. 1, in the initial magnetization, the slave disk 2 is fixed to the chuck stage 11 of the initial magnetization means 20, and an initial DC magnetic field Hin along the tangential direction of the track is generated in one direction by the electromagnet 20A. At the same time, the chuck stage 11 is rotated once or more with respect to the electromagnet 20A, and an initial DC magnetic field is applied to all track regions of the magnetic layers 2b and 2c of the slave disk 2.

  At this time, when the diameter of the slave disk 2 is 40 mm or less, the half-value width Win of the curve indicating the intensity distribution in the tangential direction of the track in the innermost track Ta of the surface of the slave disk 2 of the initial DC magnetic field is It is regulated to 125% or less of the diameter 2r of the circumferential track Ta.

  When the half-value width Win of the curve indicating the intensity distribution in the tangential direction of the track in the innermost track Ta of the initial DC magnetic field exceeds 125% of the diameter 2r of the innermost track Ta, the magnetic field deviation from the tangential direction of the track Therefore, good initial magnetization cannot be performed.

  In the present invention, by restricting the intensity distribution of the applied magnetic field in this way, in the entire track region from the innermost track Ta to the outermost track Tb, magnetization disturbance is suppressed and good initial magnetization is performed. Can do.

  Note that the initial magnetization of the slave disk 2 may be performed simultaneously on the upper and lower magnetic layers 2b and 2c of the slave disk 2 or may be performed twice on either side.

  Next, the upper and lower surfaces of the slave disk 2 that has been initially magnetized are brought into close contact with the master disks 3 and 4 and sandwiched between the holders 50 and held by a rotating means (not shown) of the magnetic field applying means 30 for transfer.

  Next, a magnetic field Hdu opposite to the initial magnetization direction is generated by the electromagnets 30A and 30B, the holder 50 is rotated by one or more rotations with respect to the electromagnets 30A and 30B, and a transfer magnetic field is applied to the entire area of the track. The information recorded as magnetic patterns on the master disks 3 and 4 is magnetically transferred to the upper and lower surfaces of the slave disk 2.

  This transcription mechanism is as follows. That is, as shown in FIG. 7B, the magnetic information is formed in the magnetic layer 3b of the master disk 3 as an uneven magnetic layer pattern. Since a magnetic field stronger than the transfer magnetic field Hdu is applied to the surface of the magnetic layer 2c of the slave disk 2 that is not in contact with the magnetic layer 3b of the master disk 3, the transfer magnetic field exceeds the coercive force Hc of the magnetic layer 2c of the slave disk 2. And the magnetization of that part is reversed.

  On the other hand, in the magnetic layer 2 c of the slave disk 2 in contact with the magnetic layer 3 b of the master disk 3, the transfer magnetic field Hdu is concentrated on the magnetic layer 3 b of the master disk 3. That is, the portion is in a state where the transfer magnetic field is shielded. As a result, only a magnetic field significantly weaker than the transfer magnetic field Hdu is applied to the magnetic layer 2c of the slave disk 2, so that the magnetization of the slave disk 2 remains in the initial magnetization direction without being influenced by the transfer magnetic field Hdu. The magnetized state is as shown in (c). As a result, the patterned magnetic information formed on the magnetic layer 3b of the master disk 3 is transferred to the magnetic layer 2c of the slave disk 2 and magnetically recorded.

  At this time, when the diameter of the slave disk 2 is 40 mm or less, the half width Wdu of the curve indicating the intensity distribution in the tangential direction of the track on the innermost track Ta of the surface of the slave disk 2 of the transfer magnetic field Hdu is set to the maximum. It is regulated to 125% or less of the diameter 2r of the inner track Ta.

  If the half-value width Wdu of the curve showing the intensity distribution in the tangential direction of the track in the innermost track Ta of the transfer magnetic field exceeds 125% of the diameter 2r of the innermost track Ta, the magnetic field deviation from the tangential direction of the track Is large and good magnetic transfer cannot be performed.

  In the present invention, by restricting the intensity distribution of the transfer magnetic field Hdu in this way, magnetization disturbance is suppressed in all track regions from the innermost track Ta to the outermost track Tb, and good magnetic transfer is achieved. It can be carried out.

  In this embodiment, the electromagnets 20A, 30A, and 30B are used as members that generate a magnetic field in the initial magnetization unit 20 and the transfer magnetic field applying unit 30, but the present invention is not limited to this, and a permanent magnet is used. A magnetic field may be generated.

  Further, although the magnetic transfer device 10 has been described with the configuration in which the slave disk 2 and the master disks 3 and 4 are held horizontally, the magnetic transfer device 10 is not limited to the horizontal direction, and may be configured to hold in the vertical direction. You may make it hold | maintain in the direction inclined at an angle.

The perspective view which shows the initial magnetization means of the magnetic transfer apparatus which concerns on embodiment of this invention Plan view for explaining initial magnetization Side view and magnetic field strength distribution diagram for explaining initial magnetization The perspective view which shows the magnetic field application means for a transfer of the magnetic transfer apparatus which concerns on embodiment of this invention Plan view and magnetic field strength distribution diagram for explaining the magnetic field for transfer Exploded perspective view explaining the holder Conceptual diagram explaining the magnetic transfer process

Explanation of symbols

2 ... Slave disk (transfer target disk); 2b, 2c, 3b, 4b ... magnetic layer; 2r ... innermost track diameter; 3, 4 ... master disk; 10 ... magnetic transfer device; ... transfer magnetic field applying means; Hin ... initial DC magnetic field; Hdu ... transfer magnetic field; T1, T2 ... track; Ta ... innermost track; Win, Wdu ... half-value width

Claims (2)

While applying an initial DC magnetic field to the disk-shaped transfer target disk, the transfer target disk is rotated relative to the initial DC magnetic field so that the magnetic layer of the transfer target disk is oriented in one direction of the concentric circular track. An initial magnetization means for initial magnetization, a master disk having a patterned magnetic layer on the surface for transferring information to the magnetic layer of the transfer target disk, and a magnetic layer of the initial magnetized transfer target disk And the transfer disk and the master disk are integrally rotated relative to the transfer magnetic field while applying a transfer magnetic field in a direction opposite to the initial magnetization direction. A magnetic transfer device comprising a transfer magnetic field applying means for magnetically transferring the information to the magnetic layer of the transfer target disk,
The initial magnetization means and the transfer magnetic field applying means have a full width at half maximum of a curve indicating the intensity distribution in the tangential direction of the innermost track on the surface of the disk to be transferred, and the diameter of the disk to be transferred is 40 mm. In the following cases, the initial DC magnetic field and the transfer magnetic field which are 125% or less of the diameter of the innermost track are applied. While applying an initial DC magnetic field to the disk-shaped transfer target disk, the transfer target disk is rotated relative to the initial DC magnetic field so that the magnetic layer of the transfer target disk is oriented in one direction of the concentric circular track. An initial magnetization means for initial magnetization, a master disk having a patterned magnetic layer on the surface for transferring information to the magnetic layer of the transfer target disk, and a magnetic layer of the initial magnetized transfer target disk And the transfer disk and the master disk are integrally rotated relative to the transfer magnetic field while applying a transfer magnetic field in a direction opposite to the initial magnetization direction. , Using a magnetic transfer device comprising a transfer magnetic field applying means for magnetically transferring the information to the magnetic layer of the transfer target disk,
Half of the curve showing the intensity distribution in the tangential direction of the innermost track on the surface of the disk to be transferred, of the initial DC magnetic field applied by the initial magnetization means and the transfer magnetic field applied by the transfer magnetic field application means A magnetic transfer method characterized in that the value width is set to 125% or less of the diameter of the innermost track when the diameter of the disk to be transferred is 40 mm or less.

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