JPH0263258B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bias magnetic head for magnetic transfer used when magnetically recording recorded content on a magnetic recording medium is transferred onto another magnetic recording medium.

This type of magnetic transfer usually involves placing a blank medium having a magnetic layer with a low coercive force on a mother medium on which recording has been made in a magnetic layer with a high coercive force, and then placing both magnetic layers of these magnetic media in close contact with each other. In this state, a bias magnetic field is applied from the outside to transfer the magnetic recording on the mother tape to a blank tape.

When performing such magnetic transfer, what is required is that both the mother and blank magnetic media are transferred stably at a high speed, for example, 2 to 4 m/s, while
It is desired that the transfer be performed by passing through a bias magnetic field for the transfer with the magnetic layers of both media in good contact with each other and without any misalignment between the two. Various types of bias magnetic heads for magnetic transfer have been proposed that provide a bias magnetic field for performing magnetic transfer. For example, as shown in the schematic configuration of FIG. 1, transfer is performed while moving both the mother and blank magnetic media to obtain high transfer efficiency, and moreover, to prevent misalignment between the two media. Therefore, a system with a symmetrical arrangement for both media was proposed. That is, in the structure shown in FIG. 1, both magnetic media, that is, the mother tape 1 and the blank tape 2, are moved from the feed rolls 3 and 4 to the take-up rolls 5 and 6, respectively. A pair of pressure rollers 7 and 8 are provided in the middle of the transfer of both tapes 1 and 2, which sandwich and press and roll both tapes 1 and 2 so as to bring them into close contact. 1
A pair of magnetic heads 9 and 10 are arranged to apply a transfer bias to the close contact portions of the two magnetic heads 9 and 10. However, with such a configuration, both magnetic heads 9 and 1
Since a bias magnetic field of 0 is applied to the tapes 1 and 2 via the pressure rollers 7 and 8, the distance between the tapes 1 and 2 and the magnetic heads 9 and 10 corresponds to the respective thicknesses of the rollers 7 and 8. Because of this, a bias head with a large magnetomotive force is required, and the attenuation of the bias magnetic field becomes slow. It has some drawbacks, such as the need to Furthermore, what is shown in FIGS. 2 and 3 is a case in which the magnetic gap of the common magnetic head 10 is disposed across both pressure rollers 7 and 8 in the configuration shown in FIG. In this case as well, a separation between the tapes 1 and 2 and the head pole corresponding to the thickness of both rollers 7 and 8 is essential, and the same difficulties as described above will arise.

The present invention is designed to allow transfer and transfer media (referred to as mother and blank) to be successively brought into close contact with each other without causing any positional shift, and to efficiently apply a transfer bias magnetic field during the transfer. The present invention provides a bias magnetic head for magnetic transfer.

The bias magnetic head for magnetic transfer according to the present invention will be explained with reference to FIG. 4 and subsequent figures. In the figure, H generally indicates a bias magnetic head for magnetic transfer according to the present invention.

In the present invention, FIG. 4 shows a perspective view, FIG. 5 shows a top view, FIG. 6 shows a cross-sectional view taken along line A-A in FIG. 5, and FIG. 7 shows a partial cross-section. As shown in the side view, the front core part 11 and the rear core part 12
and a non-magnetic cylindrical body 13 rotatably disposed around the front core part 11.

As shown in FIG. 8 in a top view, FIG. 9 in a front view, and FIG. 10 in a side view, the front core part 11 has a cylindrical surface part 11A having a regular cylindrical outer circumferential surface in the axially intermediate part. For example, cylindrical or cylindrical shaft portions 11B and 11C integrally formed with the cylindrical surface portion 11A are provided at both ends in the axial direction. The front core part 11 is made by joining together a pair of core halves 11a and 11b, which are split into two in a cross section including the axis, spanning the cylindrical surface part 11A and the shaft parts 11B and 11C. configured. A nonmagnetic material is interposed between these core halves 11a and 11b to form a magnetic gap.
This magnetic gap is formed as a bias magnetic field generating magnetic gap g extending in a straight line along the axial direction in a portion facing the outer peripheral surface of the cylindrical surface portion 11A. This magnetic gap g has a magnetic gap G having a gap length sufficiently larger than the gap length of the cap g in a portion deeper than the required depth and in the shaft portions 11B and 11C at both ends. These magnetic gap g and magnetic gap G are formed by forming a core half 1 made of a non-magnetic material such as forsterite, or copper, bronze, etc., such as high-density sintered magnetic ferrite.
It is filled between 1a and 11b, and these are combined by glass fusing or epoxy resin adhesive. And here the shaft parts 11B and 11C
is narrower than the outer diameter of the cylindrical surface portion 11A, and may be formed into a prismatic shape with a cylindrical front surface, for example.

On the other hand, the rear core portion 12 has a pair of front core portions 11a.
and a pair of core portions 12a and 12 corresponding to 11b.
As shown in FIG. and 11C, it is magnetically connected to the pair of core halves 11a and 11b to sandwich these halves 11a and 11b. Also, the core parts 12a and 12b of the rear core part 12
As shown in FIGS. 6 and 7, U-shaped incisions 12 _a1 and 12 _b1 are provided in each front portion of the front core portion 11 to provide a space between the cylindrical surface portion 11A of the front core portion 11 and the rear core portion 12. The required gap 14 is made to exist. Further, a winding 15 is wound around the rear core portion 12. The winding position of this winding 15 is
It is possible to wrap the core portions 12a and 12b, respectively, to wrap only to one of the core portions 12a or 12b, or to wrap the core portions 12a and 12b, or to wrap the core portions 12a and 12b. The arrangement position can be arbitrarily selected.

On the other hand, a non-magnetic cylindrical body 13 is disposed around the outer periphery of the cylindrical surface portion 11A of the front core portion 11 so as to be rotatable about the cylindrical surface portion 11A. This non-magnetic cylindrical body 13 includes, for example, small diameter portions 11 _B1 and 1 provided at both ends of the cylindrical surface portion 11A.
1 _C1 through non-magnetic rings 16 and rotatably supported by bearings 17 such as ball bearings. The non-magnetic cylinder 13 is preferably made of a ceramic cylinder such as alumina, and is preferably made of a high resistance or non-conductive material that can avoid the generation of eddy currents. Further, the non-magnetic ring 16 may be constructed of a ceramic ring, a brass ring, or the like. The non-magnetic cylindrical body 13 arranged on the outer periphery of the front core part 11 in this way
is the gap 14 formed by the cylindrical surface part 11A of the front core part 11 and 12 _a1 and 12 _b1 of the rear core part.
It is pivotally supported so as to be rotatable around a cylindrical surface portion 11A disposed therein.

To perform transfer from a mother magnetic medium to a blank magnetic medium using the magnetic head H according to the present invention described above, both magnetic media are superimposed so that their magnetic layers are in close contact with each other, and the magnetic head H is It is brought into contact with the gap g via the non-magnetic cylindrical body 13,
This can be done by relatively moving the superimposed media and magnetic head H. For example, the 11th
As shown in the figure, a magnetic head H is fixed, and a non-magnetic cylindrical body 13 that rotates in front of a magnetic gap g of the magnetic head H and a large-diameter driving roller 18 that rolls are provided. The mother magnetic medium 1 and the blank magnetic medium 2 are placed between the magnetic cylindrical body 13 with their magnetic layers closely facing each other as shown by the arrow a.
As shown in FIGS. 1 and 2b, the roller 18 can be rotated to press the non-magnetic cylindrical body 13 of the magnetic head H from one side of the magnetic head H to the other side. 19 is a guide roller for both media 1 and 2. Reference numeral 20 is a drive motor for the roller 18, and the pulley 22 of the roller 20 is driven by a belt mechanism, for example.
The rotation is transmitted to the magnetic gap g, and the rollers 20 cause the media 1 and 2 to move at a constant speed in front of the magnetic gap g. In this case, the magnetic head H
The winding 15 is energized with an alternating current of a required frequency f, for example, 50 KHz, thereby inducing an alternating magnetic flux into the rear core portion 12. In this case, the magnetic head H includes both core parts 12a-12b- of the rear core part 12.
A closed magnetic path is formed between the core half 11b of the front core part 11 - the magnetic gap g - the core half 11b - the rear core part 12a, and in front of the magnetic gap g, alternating current magnetic flux is layered through a non-magnetic cylindrical body. is applied to media 1 and 2, thereby effecting magnetic transfer.

In the example shown in FIG. 11, the magnetic media 1 and 2 are tape-shaped, for example, and the magnetic media 1 and 2 are continuously transferred so that the transfer is performed continuously. It can also be applied to transfer onto sheet media such as magnetic cards. An example of this case is shown in Figure 12.
In this case, for example, a flat substrate 23 is provided, and a mother medium 1 in the form of a sheet, for example a card, and a black medium 2 in the form of a sheet, for example a card, are attached to the magnetic layer of the substrate 23 via an elastic sheet 24 made of rubber or the like. are placed so as to face each other, and the magnetic head H is moved on top of the cards 1 and 2 by rolling them along the cards 1 and 2, as shown by the arrow c, to perform the transfer. You can also.

As described above, according to the magnetic head H according to the present invention, since the media 1 and 2 are superimposed and transferred toward the non-magnetic rotating cylinder 13 which can be moved in front of the magnetic gap g, the head The resistance due to friction with H can be made sufficiently small, thereby making it possible to perform accurate transfer without causing positional deviation between both tapes 1 and 2.

Moreover, according to the magnetic head H according to the configuration of the present invention,
The transfer can be performed both on a sheet-like magnetic medium, such as a card-like magnetic medium, and on a tape-like magnetic medium.

Further, in the case of the above-described configuration of the present invention, the magnetic media 1 and 2 are in contact with the magnetic gap g via the non-magnetic cylindrical body 13, but in this case, the non-magnetic cylindrical body 13 surrounds the entire magnetic head. Rather, by surrounding only the core part 11, its diameter can be selected to be sufficiently small, so even if this thickness is made sufficiently small, sufficient mechanical strength can be maintained. This makes it possible to sufficiently reduce the decrease in magnetic flux efficiency caused by bringing the magnetic medium into contact with the magnetic gap g via the non-magnetic cylindrical body 13.

Now, as shown in FIG. 13, the paired core halves 11
Let the gap length of the magnetic gap g formed between a and 11b be l, and the magnetic layers of the master magnetic medium 1 and the blank magnetic medium 2 are overlapped with the front surface of the magnetic gap g via the non-magnetic cylindrical body 13. The distance to the contact surfaces of 1a and 2a is d, the width from the center of the gap g of the close part of the media 1 and 2 to the non-magnetic cylinder 13 is L, and the relative speed between the head H and the magnetic media 1 and 2 is Let be υ [m/s],
When the bias current frequency is f [Hz], that is, when the virtual wavelength λ = υ/f [m], in order to effectively utilize the magnetic field in the magnetic gap g, ld...(1) is required, and under the condition of equation (1) above, it is desirable to bring the magnetic medium into close contact with the magnetic medium to a position where it attenuates to about 1/5 or less of the maximum magnetic field at the center of the magnetic gap g. Therefore, L2.5l... (2) is recommended. Furthermore, it is desired that a reversal magnetic field of 5 cycles or more is applied to the magnetic media 1 and 2 that are in close contact with each other until the magnetic field applied during transfer attenuates, and for this reason, Lf/υ5...(3) is selected, and the bias signal is In order to cause recording demagnetization to prevent recording on media 1 and 2, it is desirable to select l2υ/f (4). Now, if we choose L=2.5l...(5) as the limit condition for equation (2) and substitute this into equation (4), we get Lf/υ5...(6). This equation (6) is consistent with equation (3), so in the end,
The conditions for satisfying all equations (1) to (4) are as follows:
Equations (1), (5), and (3) l=d...(1) L=2.5l...(5) Lf/υ5...(3) Now, for example, if the gap length l of the magnetic gap g and the thickness d of the non-magnetic cylindrical body are selected to be 1 mm, then the contact distance L should be greater than L = 2.5 mm, and the head H and If the relative speed υ with magnetic media 1 and 2 is υ = 4 [m/s], then Lυ5×4 [m/s] f5×4 [m/s]/2.5×10 ^-3 [m] = 8× 10 ³ [
Hz].

As described above, according to the present invention, the rotatable non-magnetic cylindrical body 13 is disposed in front of the magnetic gap g that applies a bias magnetic field, so that the master medium and the blank medium are brought into contact with each other through this. Since the two media do not become misaligned due to sliding resistance with the magnetic head, the pressure force between the two media can be made sufficiently large, making it especially suitable for transferring short wavelength, narrow track magnetization patterns. Apply it to your advantage.

In addition, since the contact length L of both media 1 and 2 with the head H can be made relatively small to about 3 to 4 mm, the drive roller 18 as explained in FIG. capstan
Stable operation can be achieved by applying the pinch roller method.

Furthermore, even when high-speed transfer is selected, for example, the relative speed υ between the magnetic head and the magnetic medium is set to 4 [m/s],
Since the bias frequency f can be selected to be a relatively low frequency of about 10KHz or less, the design of the bias circuit,
It has the advantage of being easy to manufacture.

Furthermore, a magnetic gap g that generates a bias magnetic field
Since the distance to the overlapping plane of the magnetic layers of both media 1 and 2 can be made relatively small to 1 mm, the magnetomotive force due to the outer diameter of the head H is relatively low, for example, several times to several tens of times that of a normal erasing head. It can be driven by electricity.

Further, according to the magnetic head H according to the present invention, since the rotatable non-magnetic cylindrical body 13 is provided, it can also be used as a part of the drive mechanism for the media 1 and 2 as described above, that is, as a capstan and There is an advantage that a pinch roller configuration can be used and the medium traveling device can be simplified.

In addition, in the above explanation, the blank magnetic medium 2
It goes without saying that this refers to magnetic media on which no magnetic recording has been made, as well as media that have been once recorded and then erased using an erasing head or the like.

[Brief explanation of the drawing]

1 and 2 are layout configuration diagrams of an example of a conventional magnetic transfer head for explaining the present invention, FIG. 3 is a cross-sectional view taken along line A-A in FIG. 2, and FIG. 4 is a diagram of the present invention. FIG. 5 is a top view thereof, FIG. 6 is a sectional view taken along the line A-A in FIG. 5, FIG. 7 is a partially sectional side view, FIG. 8,
9 and 10 are top views, front views, and side views of the front core part, FIG. 11 is an arrangement diagram showing a transfer mode of the magnetic head according to the present invention, and FIG. 12 is a similar transfer of another example. FIG. 13 is a diagram illustrating the dimensional design of the present invention. H is a bias magnetic head for magnetic transfer according to the present invention, 11 is a front core portion, 12 is a rear core portion, 13
1 is a non-magnetic cylindrical body, 15 is a wire ring, 1 and 2 are a mother magnetic medium and a blank magnetic medium.

Claims (1)

[Claims] a front core portion configured with a magnetic gap that generates a bias magnetic field between a pair of core halves, and a closed magnetic circuit that includes a winding and is magnetically connected to each of the pair of core halves and includes the magnetic gap; and a non-magnetic cylindrical body rotatably arranged around the front core part through a gap provided between the front core part and the rear core part. Biased magnetic head for transfer.