JPS5826328A - Magnetic tape transfer method - Google Patents

Abstract

PURPOSE:To transfer signals from a master tape having a small coercive force to a slave tape, by applying a transfer bias magnetic field to an axis difficult for magnetization of the master tape of ferromagnetic substance thin film. CONSTITUTION:A master tape 61 having an axis 53 easy for magnetization vertically and a slave tape 62 having an axis 64 easy for magnetization to the lengthwise direction are brought into close contact with each other for the magnetic substance layers and a transfer bias magnetic field 65 is applied in the lengthwise direction of the tape. To obtain signals of good quality at magnetic field transfer, the strength of transfer bias magnetic field about 1.5 times the coericive force Hc of the slave tape is used. Thus, the change in the magnetic characteristics to the film thickness direction of the ferromagnetic thin film tape is used and the transfer bias magnetic field is applied to the direction of an axis difficult for magnetization of the master tape, allowing to transfer signals from the master tape having a comparatively small coercive force to the slave tape.

Description

Detailed Description of the Invention The present invention uses as a master tape a magnetic tape in which a ferromagnetic thin film having an easy axis of magnetization perpendicular to the film surface is provided on a non-magnetic substrate, and applies a transfer bias magnetic field to the hard axis of magnetization of the master tape. The present invention relates to a magnetic contact transfer method that enables transfer from a master tape having a lower coercive force than conventional ones by applying magnetic force in the same direction.

A typical conventional transfer method will be explained using FIG. 1 and subsequent figures. FIG. 1 shows a schematic configuration diagram of the batch winding transfer system. A recorded master tape 1 and an unrecorded Nureve tape 3 are supplied from a recorded master tape supply reel 2 and a Nureve tape supply reel 4, respectively, and run with their magnetic layers facing each other. Next, both tapes 0 are wound around the sliding surface of the fixed guide post 9 at a certain angle, and then, in this state, are wound around the capstan 5 at a certain angle, and then wound together on the take-up reel 10. The take-up reel 10 is provided on an arm 12 that is rotatable around a fulcrum 11, and the take-up reel 10 is always rotated by the urging force of a spring 8.
The outermost peripheries of the two windings f6 are brought into pressure contact with the capstan 5, and the windings of both windings enter the transfer bias generator 7 as they are wound.

After being wound, the tape is rotated at a low speed while the transfer bias generator 7 applies a transfer voltage in the longitudinal direction of the tape, and the signal on the master tape is transferred onto the slave tape. That will happen. Next, both supply reels 2 and 2 at 7'fB high and high speed.
The figure shows a schematic diagram of the structure of the transfer/myias generator, and FIG. 3 shows a diagram of the principle of transfer. A current is passed through the excitation coil 13 between a magnetic core 14 made of laminated silicon steel plates and a magnetic core 15 facing it to generate a magnetic field 16, and the magnetic field is applied in the longitudinal direction of both wound tapes 6. ′″)−
! In FIG. 3, XyVtZ indicates the longitudinal direction, middle direction, and thickness direction of the tape, respectively, and the transfer bias magnetic field 16 is mainly applied in the longitudinal direction of the tape as indicated by the arrows.

In this way, the magnetization 20 of the magnetic layer 17 of the master tape 1
The magnetic layer 18 of the slave tape 3 is magnetized by the signal magnetic field 19 generated from the master tape, and the signal on the master tape is transferred to the slave tape.

Typical transfer characteristics obtained by transfer using the above-mentioned method are shown in FIG.

The slave tape has a coercive force He of 6700e.

A Co-based iron oxide tape with Br of 1470 gauss was used.

Generally, when transferring a signal from a master tape onto a slave tape, the coercive force of the master tape is required to be about 2.5 to 3 times that of the slave tape. Figure 4 shows 15000e and 20000e for the slave tapes mentioned above.
Transfer characteristics were measured using a master tape having a coercive force of e.

The relative speed of Henodoteso at this time is 5.8 ml
sec, and a signal with a recording wavelength of about 1 μm was used.

For a master tape with a coercive force of 1500 Qe, as the transfer bias field strength is increased, the transfer output level 21 gradually increases, the magnetization on the master tape is erased by the transfer pieanu magnetic field, and the master tape output level 2
It reaches a maximum near the point where 3 starts to decrease, and then attenuates as the master tape output decreases.

On the other hand, in the case of a master tape with a coercive force of 20000e, as shown in characteristic 24, it is difficult to be erased by the transfer bias magnetic field, so it is difficult to obtain a large or medium transfer output with respect to the transfer bias, as shown in characteristic 22. I can do it.

As described above, in order to obtain a high quality signal, the He of the master tape must be extremely large compared to the coercive force of the slave tape. In the above example, for 20000e,
It is approximately three times as large as the slave tape.

In addition, in the future, alloy powder tapes or ferromagnetic thin film tapes with a He of around 10,000e will be prototyped as video tapes, and if these are used as slave tapes, the master tape will need to have a coercive force of about 30,000e or more. It turns out. 15000e and 20000e mentioned above
The master tape is Fe-C.

Although it is made by coating fine particles of alloy powder, it is extremely difficult to achieve a coercive force of 30,000 e with a coated tape, and there are currently no prospects for development. Also,
The same holds true for ferromagnetic thin film tapes. On the other hand, there are also problems with the recording head, such as the possibility of recording on this tape due to magnetic saturation.

In view of this point, the present invention makes use of changes in the magnetic properties of a ferromagnetic thin film tape in the film thickness direction, and applies a transfer bias magnetic field in the direction of the hard-to-magnetize axis of the master tape (5), thereby producing a relatively small coercive force. This allows signals to be transferred from a master tape having a nucleation tape to a nurev tape.

The master tape used in the present invention is prepared by depositing Co-Cr, Co-V on a film of polyethylene terephthalate, polyimide, polyamide-based organic material, or other non-magnetic substrate by means such as vapor deposition or Nui97 tamesoki.
+ A ferromagnetic thin film having an axis of easy magnetization perpendicular to the film surface, such as Co--Mo, is formed and slit into a tape shape. The present invention will be described below with respect to a tape-shaped magnetic medium, but it is equally useful for sheet-shaped magnetic media.

The principle of the present invention will be explained using a rotation model of an explanatory element with reference to FIG. 5 and subsequent figures.

As shown in FIG. 5, one direction in the plane of the ferromagnetic metal thin film 25 on the non-magnetic substrate 26 is taken as the X axis 30, and the direction perpendicular to the film surface is taken as the two axes 31. ) When the intensity H of the field 27 and the angle ψ it forms with the X axis are variable, the energy E is expressed by the following formula.

E = M Hcos (ψ-θ.-θ) -1-Kd
5in2ψ+Kusin2θ Note that Kd is an anisotropy constant due to the demagnetizing field and is equal to 2πM. Also, the angle between the easy magnetization axis direction and the X-axis is θ. Closed. Ku is a uniaxial anisotropy constant.

At this time, the magnetization M is stabilized in a state that minimizes the energy in the above equation, and is stabilized at an angle θ with the easy magnetization axis direction 29.

It is assumed that Mo32 is oriented in the X-axis direction (in this case, coincident with the magnetic and easy axis). On the other hand, if a magnetic field n, 33 is applied at an angle ψ, the magnetization will point in the direction 34 as described above, and if Hl is removed again, it will return to the position 32 and point in the X-axis direction.

Further, in order to reverse the MO once magnetized in the X direction, ψ needs to be 90° or more.

First, consider the case where magnetic fields H235 and H336 are applied at an angle ψ of 90° or more. In the case of 11□35 where the magnetic field strength is weak, the magnetization slightly deviates in the direction of the magnetic field as shown by the vector 39, but when the magnetic field is reduced to zero, it returns to the X-axis direction.

However, in the case of H336 with a sufficiently large magnetic field strength, it rotates to the position of vector A37, and when the magnetic field H3 is made zero, the magnetization settles at the position shown at 38 and is reversed from the original 32 to 38. Therefore, the magnetization is M.

I am reminded of the reversal from -MO to -MO. Next, if H440 is increased by applying the magnetic field in two directions, the magnetization vector will point in the direction 41 while the magnetic field is applied, but
When the magnetic field is removed, it returns to the original position 32 in the X-axis direction.

If the above is explained in an easy-to-understand manner using an MH curve, it will be as shown in Fig. 7.

Figure 7 42 and 43 show the amount of magnetization in each direction when a magnetic field H is applied in the easy axis direction (ψ-0°, 180°) and hard axis direction (ψ-90°) of a single magnetic domain particle, respectively. It represents M.1 This is stor
This is known as the ner-world model.

That is, 42 applies a magnetic field and then a reversal field until removed, o-a-b-c-b-d-e-f-g-h
-g-i M-H curve, 43 is ob-
c-b-o-g-h-go-o. What is clear from this is that 42 is completely magnetized in the direction of the magnetic field even after the magnetic field is removed, and 43 is not magnetized at all in the direction of the magnetic field. Therefore, 42 is suitable as a slave tape in which as much residual magnetization as possible is required by the signal magnetic field generated from the tape under the action of the transfer bias magnetic field.

On the other hand, the characteristic of the master tape 43 is that the signal magnetization is not erased even by a strong transfer bias magnetic field.

Therefore, it is desirable to apply the transfer magnetic field as much as possible to the master tape in the direction of the axis of hard magnetization and to the slave tape in the direction of the axis of easy magnetization. However, in the case of an actual tape, it is considered to be an aggregate of the single magnetic domain particles mentioned above, so an ideal M-H curve with good squareness cannot be obtained.
The shape becomes dull.

(9) Next, the magnetic properties of the master tape used in the present invention will be explained.

The method for measuring the ν magnetic properties is as shown in FIG. 8(A).

The longitudinal direction of the prototype tape 044 is placed in the X-axis direction, the force direction is perpendicular to the paper surface, and the tape thickness direction is placed in the Z-axis, and an external magnetic field H is applied diagonally to the tape surface to generate a vibrating sample-shaped magnetism. This figure shows the arrangement when measuring using a characteristic measuring device (VSM).

FIG. 8(B) is a B-H curve obtained by changing the angle ψ of the external magnetic field H relative to the tape surface in the arrangement shown in FIG. 8(A). For example, 45.46 is the value of ψ, respectively. This is a curve when is 90° and Oo. As can be seen from Fig. 8 (B), the coercive force (c) and the squareness ratio Br78m vary greatly depending on the direction ψ of the external magnetic field. Shows HC and Br78m.

Note that when ψ-90°, a demagnetizing field proportional to 4πM acts in the thickness direction, so B -Hcu'rve
is sharing. Therefore, Br corrected for this magnetic field was calculated on the drawing (10) and Br78m was determined as shown in 47.

As shown in FIG. 9, the curve 48 of the coercive force (coercive force) 1c monotonically decreases as the direction ψ to which the external magnetic field H is applied approaches the longitudinal direction of the tape, and at the same time, Br78m 47 has similar characteristics. As described above, this characteristic is close to the characteristic of single-domain particles, and indicates that the longitudinal direction (0°) of the tape is the direction of the difficult axis of magnetization.

Next, the principle of contact transfer according to the present invention will be explained using FIG. 10.

As shown in FIG. 10(A), a master tape 49 having an axis of easy magnetization perpendicular to the tape surface and a slave tape 50 having an axis of easy magnetization in the plane are used to record signals on the master tape. Signal magnetic field 5 generated from magnetization 51
2, the case where the magnetic layer flf5 of the slave chip is magnetized will be explained.

When the master tape 49 and the slave tape 50 are in contact with each other, as will be described later, a transfer bias magnet is applied in a direction in which the signal magnetization on the master tape is difficult to erase.
), an effective magnetic field 56 resulting from the combination of the signal magnetic field 54 and the transfer bias magnetic field 55 is applied to the Nureve tape.
When the magnetization 53 on the Nureve Tezo is reversed according to the aforementioned principle, it is magnetized by the signal magnetic field 54 on the master tape, and the signal magnetization is transferred onto the Nureve Tezo.

Naturally, a characteristic required of a master tape is that the signals recorded on the master tape are not erased by a transfer bias magnetic field of a sufficiently high level, and a strong signal magnetic field is always generated.

Below, the influence of the strength of the reversal magnetic field of signal magnetization and the direction of the applied magnetic field, which was discovered by the present inventor, will be explained. In this case, the reversal magnetic field is a transfer bias magnetic field.

Figure 11 shows the maximum residual magnetic flux density B r q when a vertically anisotropic tape with Hc = 9500e (perpendicular to the surface) and Br = 7000 gauss is magnetized to saturation by a sufficiently large DC magnetic field in the direction perpendicular to the tape surface.
.

A reversal magnetic field is applied to the tape in this state while changing the applied direction and intensity, and the residual magnetic flux density Br9. (Ratio of residual magnetic flux density in the vertical direction) B r cp / B r q
This is a measurement of the change in o.

The reversal magnetic field strength is 500. lk, 2, 3k.

The measurement was performed by changing the value to 4k Oe.

As can be seen from Figure 11, when the magnetic field strength is relatively small,
Br9 for ψ. /Brq. It was found that the value changes gradually, but it changes sharply as the magnetic field strength increases.

As mentioned above, the direction of the difficult magnetization axis of this tape is ψ=0°
That is, in the longitudinal direction of the tape, for example, when the reversal magnetic field strength is 1
In the case of kOs, an angle that is difficult to erase occurs in the range of -30° to +30°.Next, the magnetic properties of coated type and obliquely deposited tapes used as nureve tapes will be explained using examples.

FIG. 12 shows measurements taken by changing the direction ψ of the external magnetic field H using the measurement method shown in FIG. 8(A). 60 and 59 show the characteristics of He and Br78m of Co-iron oxide coated tape, respectively. In the case of this coated tape, the longitudinal direction of the tape in the plane is the axis of easy magnetization, and ψ
There is a gentle peak of He in the vicinity of =±50°, and when ψ is further increased, He decreases. Also, Br78m is
As the absolute value of ψ increases, it shows a monotonically decreasing characteristic.

Note that Hc-6700e in the longitudinal direction of this tape.

Br　　　1470　gauss.

On the other hand, Hc in the longitudinal direction = 10000e, Br = 7000
In the case of Gauss obliquely vapor-deposited tape, as the angle ψ increases in the negative direction as shown in 57, Hc increases and reaches its maximum value near -60°, and as it increases further, it reaches -70°.
It shows a local minimum value in the vicinity and then increases again. This vicinity of -70° is considered to be the direction of the axis of difficulty in magnetization of this obliquely deposited tape.

Further, Br78m58 shows a maximum near +20°, which indicates that the axis of easy magnetization is inclined at +20° with respect to the longitudinal direction of the tape in the plane.

Next, a specific embodiment of the present invention will be described.

FIG. 13 shows the positional relationship in the case of contact transfer between the above-mentioned master chip 7'61 having the axis of easy magnetization 63 in the vertical direction and the Nure-Buti-Zoro 2 having the easy axis of magnetization 64 in the longitudinal direction. .

As shown in Figure 13, the magnetic layers of both tapes are brought into close contact with each other,
A transfer bias magnetic field 65 was applied in the longitudinal direction of the tape. Therefore, the operating point of the direction of the transfer bias magnetic field is ψ-θ° in FIG. 9 with respect to the master tape, and the operating point is ψ-0° in FIG. 12 with respect to the nucleator. - In general, in order to obtain a high-quality signal with magnetic field transfer, a transfer bias magnetic field strength of about 1.5 times that of the slave tape's He is required, so in this case, a transfer bias magnetic field of approximately l]<Oe is used. Ta.

In the second example, as can be seen from FIG. 11, the signal on the master tape was degraded within 0.5 dB, and a good quality signal was transferred. ′! , Hc in the longitudinal direction is 140
Even when a 00e Fe-based alloy powder tape is used as a slave tape, signal deterioration of the master tape can be kept within 0.5 dB by using a transfer bias magnetic field strength of 2.1 koe, and a high-quality image signal can be obtained without any problems in practical use. was gotten.

In the case of the above example, the direction of the transfer bias magnetic field was selected to be ψ-00, but as a result of experiments with changing ψ, as can be seen from Figure 11, the direction of the transfer bias magnetic field was -2 to -3 dB in the range of -25° to +25°.
The deterioration of the master tape signal remains within this range, and within this range, a transfer signal with no practical problems can be obtained.

FIG. 14 shows an example in which the above-mentioned obliquely vapor-deposited tape is used as a slave tape. As mentioned above, the axis of easy magnetization 66 of the obliquely deposited Chisoro 8 is +20°. Therefore, by selecting the direction ψ of the transfer bias magnetic field 67 near +20° and performing the transfer, as can be seen from FIG. The operating point where the mold ratio is maximum and He is minimum can be selected and transferred.

Figure 12: He of the vapor-deposited tape at ψ=120° is 10
000e, and therefore the transfer magnetic field strength was about 1.5 koe.

As described above, an excellent transfer signal could be obtained by applying a transfer bias magnetic field in the direction of the axis of easy magnetization of the obliquely deposited tape within the range of -25° to +25°.

As described below, according to the conventional transfer method, the He of the master tape needs to be three times or more the He of the slave tape. Further, problems such as saturation of the recording head and other problems associated with this have also arisen. However, if this method is used, it is possible to perform contact transfer from a master tape having He of the same degree as that of the slave tape, and it is possible to obtain, for example, an image signal of good quality.

As described above, according to the present invention, (1) it is possible to transfer from a master tape having an axis of easy magnetization perpendicular to the tape surface and a relatively small Hc. Also, when recording on a master tape, since He is small, the problem of saturation of the magnetic head can be solved.

■ By selecting the direction of the transfer bias within the range of 25 degrees in the positive direction and 25 degrees in the negative direction with respect to the master tape's difficult-to-magnetize axis direction, the signal on the master tape can be used with almost no erasure. 17) High quality transcription output can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a conventional transfer device, Fig. 2 is a block diagram of a conventional transfer bias magnetic field generator, Fig. 3 is a diagram of the principle of conventional transfer, Fig. 4 is a diagram of conventional transfer characteristics, and Fig. 5 is a block diagram of a conventional transfer bias magnetic field generator. Figure 6 is an explanatory diagram of anisotropy regarding ferromagnetic metal thin film tape, Figure 6 is an explanatory diagram of anisotropy regarding ferromagnetic metal thin film tape, Figure 7 is an M-H characteristic diagram of ferromagnetic metal thin film tape, and Figure 8 is an explanatory diagram of anisotropy regarding ferromagnetic metal thin film tape. The figure shows the characteristic measurement method and characteristic diagram in the thickness direction of the magnetic tape. Figure 9 is the characteristic diagram of He and Br/Bm of the master tape.
The figure shows the principle of contact transfer according to the present invention, Figure 11 shows the characteristics of the master tape with respect to the direction and intensity of the transfer/bias magnetic field according to the present invention, and Figure 12 shows the characteristics of He and Br/Bm of the oblique vapor deposition tape and coated tape. The characteristic diagram, FIG. 13, is a diagram showing one embodiment of the present invention, and FIG. 14 is a diagram showing one embodiment of the present invention. ■... Recorded master tape, 2, 4... Supply IJ
3...Slave tape, 7...Transfer bias generator, 10...Take-up reel, 13...Excitation coil, 14° (18) 15...Magnetic core, 17'+18... -Magnetic layer, 49.
61...Manutate 70.50, 62...Nureve tape, 65.67...Transfer bias magnetic field. Figure 1 Figure 2 1) +9'T! , 1! -Hal +Ell)) 9
J tN ,'-right,, t -1γ Fig. 5 7 Fig. 6 Fig. 8 (A) 8 ■ 4 0 (8) Fig. 7 Fig. 9 te (maro) Fig. 11 Inverted through/outward n (Bruce) Figure 10 'f' (,41

Claims (1)

[Claims] A magnetic tape with a ferromagnetic thin film having an axis of easy magnetization perpendicular to the film surface of Co-Cr is formed on a non-magnetic substrate, and a recorded master tape on which signals are recorded and a magnetic layer of an unrecorded Nureve are interchanged. A magnetic tape characterized in that the signals on the master tape are transferred onto a slave tape by applying a transfer bias magnetic field from the outside within a range of ±25° around the direction of the hard magnetization axis of the master tape. Transfer method.