JPS59215003A - Magnet erasing head - Google Patents

Abstract

PURPOSE:To obtain a high performance erasing characteristic with less erasing noise and distortion factor at recording by laminating many sheets of magnetic material having a magnetic anisotropy in the running direction of a tape while clipping a nonmagnetic material so as to increase easily the number of poles. CONSTITUTION:Vertically magnetized magnetic poles 22 made of a magnet material having the magnetic anisotropy in the upper stream direction to the running direction of the magnetic tape and in the broadwise direction of the magnetic tape and horizontally magnetized magnetic poles 23-27 made of a magnet material having the magnetic anisotropy in the running direction of the magnetic tape toward the downstream are arranged in a core 21 of a magnet erasing head 20 and a spacer 28 made of a nonmagnetic material is inserted between each magnetized magnetic poles. The poly-pole is realized easily by making the thickness of the spacer and the horizontally magnetized magnetic pole thin and an optional magnetizing pattern is obtained stably by selecting the thickness. Further, a strong erasing magnetic field saturating magnetically even the magnetic tape having a high coercive force such as metal tape sufficiently is obtained by providing the vertically magnetized magnetic poles toward the upperstream.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic erasing head for erasing a magnetic tape used in a magnetic recording device such as a tape recorder.

The structure of the conventional example and its problems The conventional example will be explained with reference to FIGS. 1 to 6. 1 is a magnetic tape, 2 is a tape guide, 3 is a recording/playback head, 4 is a core, 6 is a conventional magnetic erase head, 6
is its core, 7 to 10 are magnetized magnetic poles magnetized to the core 6 of the magnet erase head 5, 11 is a magnetizing device for magnetizing the conventional magnet erase head 6, and 12 to 15 are its magnetized windings. line, 1
6 to 19 are magnetizing yokes.

The conventional magnetic erase head 5 has a core 6 in which magnetized magnetic poles adjacent to each other in the running direction (arrow) of the magnetic tape are different, as shown in FIG. 2, and magnetized as shown in FIG. The strength of the magnetic poles is configured to gradually attenuate in the running direction of the magnetic tape. Note that a, b, a in Figure 3
and d are the magnetization strengths of the magnetization magnetic poles 7, 8, 9, and 10, respectively.

As shown in FIG. 1, when the front surface of a conventional magnetic erase head 5 is run in the direction of the arrow in order to erase the magnetic tape 1, the process of magnetizing the magnetic tape 1 by the core 6 of the magnetic erase head 5 occurs. The zero magnetic tape 1 explained according to FIG. 5 is magnetized to saturation 1 at the magnetized magnetic pole 7 (magnetization strength a) of the core 6, and then the residual magnetization becomes zero at the magnetized magnetic poles 8 to 10. Attenuation occurs while reversing the magnetization. However, in this case, due to variations in the magnetic properties of the particles in the core 6, changes in the magnetization strength of the magnetized magnetic pole due to changes in the magnetization conditions, changes in the contact between the core 6 and the magnetic tape 1, etc., as shown in FIG. The magnetization of the magnetic tape 1 by the magnetized magnetic pole 9 changes from C to C.
', residual magnetization e occurs in the magnetic tape 1 after erasing, which causes noise during playback and distortion during recording.

In order to eliminate this drawback, it is possible to increase the number of magnetized magnetic poles so that residual magnetization is less likely to occur even if the magnetization changes as described above, but the conventional magnet erase head 5 generally has the structure shown in Fig. 4. Since the magnetizing device 11 as shown in FIG. The distance between the magnetic poles could not be made too narrow due to the space of the magnetized winding and its insulation, and a sufficient number of magnetized magnetic poles could not be obtained.

In addition, in FIG. 4, the core 6 of the conventional magnet erase head 5 is pressed against the magnetizing yoke of the magnetizing device 11, and the core 6 of the conventional magnet erasing head 5 is pressed against the magnetizing yoke of the magnetizing device 11. By passing a magnetizing current through the magnetizing windings 12, 13, 14, and 15, υ magnetized magnetic poles 7, 8, 9, and 1o are formed. The magnetization strength of the magnetization pole is controlled by the width of the magnetization yoke, the magnitude of the magnetization current, the number of turns of the magnetization winding, the wire diameter, and the position.

Purpose of the Invention In order to eliminate such drawbacks, the present invention aims to realize a magnetic erasing head that eliminates noise and distortion during recording and playback by providing a large number of magnetized magnetic poles in a limited core width dimension. .

Structure of the Invention The present invention provides one or more magnetic abrasive material having magnetic anisotropy in the thickness direction of the magnetic tape and one or more magnetic material having magnetic anisotropy in the running direction of the magnetic tape. This is a magnetic erasing head in which a core portion is constructed by interposing a non-magnetic material in the tape, and the magnetic material having magnetic anisotropy in the thickness direction of the tape provides an erasing magnetic field capable of magnetically saturating the magnetic tape sufficient for erasing. The number of poles can be easily increased by stacking magnetic materials with magnetic orientation in the tape running direction with a non-magnetic material interposed between them. Pseudo-AC erasing in which the magnetic field strength gradually decreases while the polarity reverses as the recording progresses can be easily realized, and high-performance erasing characteristics with less erasing noise and less distortion during recording can be obtained.

DESCRIPTION OF EMBODIMENTS The structure and operation of the present invention will be explained with reference to FIGS. 6 to 12. 20 is a magnetic erase head which is an embodiment of the present invention; 21 is its core; 22 is a magnet material having magnetic anisotropy in the thickness direction of the magnetic tape; 1 vertically magnetized magnetic poles 023-27
are first to sixth horizontally magnetized magnetic poles made of a magnetic material having magnetic anisotropy in the running direction of the magnetic tape, and magnetized in the running direction of the magnetic tape. 28 is a spacer made of non-magnetic material, 29 is an upper magnetizing yoke, 30 is a lower magnetizing yoke,
31 is a magnetizing winding.

7/ of the magnetic erase head 20 which is an embodiment of the present invention.
・7 The core 21 includes a core made of a magnetic material having magnetic anisotropy in the thickness direction of the magnetic tape on the upstream side with respect to the running direction of the magnetic tape, as shown in FIGS. 6, 7, and 9. 1 vertically magnetized magnetic pole 22, and first to sixth horizontally magnetized magnetic poles 23 to 27 made of a magnetic material having magnetic anisotropy in the running direction of the magnetic tape are arranged downstream (1). A spacer 28 made of a non-magnetic material is interposed therebetween.

As shown in FIG. 11(7), the core 21 of the present magnet tracking head 20 is formed between the upper magnetizing yoke 29 and the lower magnetizing yoke 30 by first passing a magnetizing current through the magnetizing winding 31. The first perpendicularly magnetized magnetic pole 22 of the core 21 of the magnet erase head 20, which is placed so that the front surface faces the axial direction of the magnetized yoke, is magnetized, and the magnet is then magnetized as shown in FIG. 11(a). Erase head 2
0 is arranged so that the front surface faces in the direction 90 with respect to the axial direction of the magnetizing yoke, and a magnetizing current I is applied to the magnetizing winding 31 to magnetize the first to fifth horizontal magnetizing magnetic poles of the core 21. Finally, magnetized magnetic poles as shown in FIGS. 9 and 10 are obtained.

In FIG. 10, a is the magnetization strength of the first vertically magnetized magnetic pole 22, and 10 and 10 are the N of the first horizontally magnetized magnetic pole 23, respectively.
The magnetization strengths of the poles and S poles, 10C and -d, 10d and -d, 10e and -e1, 10f and -f are the N and S poles of the second to fifth horizontally magnetized magnetic poles 24 to 27, respectively. It is the magnetization strength of the pole.

As shown in Figures 7 and 8, horizontally magnetized magnetic pole 23.2
The thickness of the spacer 28' is set by 4, 25, 26, 271 so that the one on the downstream side is not thicker than the one on the upstream side in the running direction of the magnetic tape (1, ≧t2≧t5≧t4)
t5) By configuring the structure, the distance between adjacent magnetic poles becomes smaller toward the downstream in the tape running direction, and the mutual demagnetization (cancellation) of the magnetic poles is reduced, resulting in the magnetization of the Mizuko N magnetic @ pole. As shown in FIG. 10, the strength is configured so that its polarity does not reverse but gradually decreases.
Multipolarization can be easily realized, and by selecting the thickness, any desired magnetization pattern can be stably obtained. Due to the coercive force of the tape, a strong magnetization strength, that is, an erasing magnetic field, can be obtained, which can sufficiently magnetically saturate even a magnetic tape. Furthermore, regarding magnetization, as shown in FIG. 11(a), it is possible to magnetize a large number of magnets at once, and the M@ device can be easily configured.

FIG. 12 shows the magnetization process when the magnetic tape 1 is erased using the magnetic erase head 20 as shown in FIG. 6. 12th
As shown in the figure, by increasing the number of horizontally magnetized magnetic poles, the residual magnetization can be stably converged to zero even if the magnetization strength changes slightly, and with vertically magnetized magnetic poles, the residual magnetization can be stably converged to zero. Even tapes with large coercive force, such as metal tapes, can be sufficiently magnetized at saturation 1.

Figures 13 and 14 show the results of comparing an embodiment of the present invention with a conventional cassette tape recorder, where curve P is the embodiment, curve Q is the conventional example, and curve S is the erase head. is an unrelated value of the system itself. That is, in the present invention, the distortion rate at the time of recording of 5 to 1 oaB% in erasure noise can be improved by 310/.-6%.

Effects of the Invention The present invention provides at least one magnetic material having magnetic anisotropy in the thickness direction of a magnetic tape and one or more magnetic phase material having magnetic anisotropy in the running direction of the magnetic tape, and also provides at least one magnetic phase material having magnetic anisotropy in the running direction of the magnetic tape. This is a magnetic erasing head with a core made up of a non-magnetic material interposed between the tape and the tape. ), it is possible to obtain an erasing magnetic field that can magnetically saturate the magnetic tape sufficiently for erasing, and by magnetizing in the running direction of the tape, magnetic anisotropy is created in the running direction of the tape. It is possible to obtain a magnetized magnetic pole at the end of the part where the magnet material having a By decreasing the thickness of the magnetic material and non-magnetic material toward the downstream side with respect to the tape running direction, the polarity can be gradually reversed and the polarity can be increased by 111°.
It is possible to realize pseudo AC erasure in which the dimagnetic field strength is attenuated, and the erasure can be completely performed using a magnetic material having magnetic anisotropy in the thickness direction of the magnetic tape provided on the upstream side in the tape running direction, and also on the downstream side. The pseudo-AC erasing section is constructed by laminating magnetic materials with magnetic anisotropy in the running direction of the magnetic tape with non-magnetic materials interposed in between, which provides high-performance erasing characteristics with less erasing noise and distortion during recording. is obtained.

[Brief explanation of the drawing]

Figure 1 is a perspective view showing the magnetic tape running state of a conventional magnetic erase head, Figure 2 is a perspective view showing the magnetized state of the conventional magnetic erase head, and Figure 3 is the magnetization strength of the conventional magnetic erase head. 4 is a perspective view of the magnetizing device of a conventional magnetic erase head. FIG. 5 is a characteristic diagram showing the magnetization process when erasing a magnetic tape with a conventional magnetic erase head. FIG. 7 is a perspective view showing the magnetic tape running state of a magnetic erase head according to an embodiment of the present invention; FIG. 7 is a perspective view showing the magnetized state of the present embodiment; FIG. 8 is a perspective view of another embodiment; FIG. 9 is a top view showing in detail the magnetized state of the core of this example, FIG. 10 is a characteristic diagram showing the magnetization strength of this example, and FIGS. A front view showing the magnetizing device, FIG. 12 is a characteristic diagram showing the magnetization process when a magnetic tape is erased as shown in FIG. 6 using this embodiment, and FIG. 13 shows a conventional magnetic erasing head and this embodiment. Fig. 14 is a characteristic diagram comparing the erasure noise of the magnetic erase head of the present invention, and Fig. 14 is a characteristic diagram comparing the distortion rate during recording of the conventional magnetic erase head and this embodiment. Magnet material having magnetic anisotropy in the thickness direction, 23-27... Magnet material having magnetic anisotropy in the running direction of the magnetic tape, 28...
...Non-magnetic material. Name of agent: Patent attorney Toshio Nakao and one other person 12th evening, Ward C Tsubo 14 [Ni.

Claims (4)

[Claims] (1) At least one magnetic phase material having magnetic anisotropy in the thickness direction of the magnetic tape and one or more magnetic material having magnetic anisotropy in the running direction of the magnetic tape are provided, and there is no non-contamination between each magnetic material. Nod to magnet erasing, characterized in that the core part is constructed by interposing a magnetic material (2) Place a magnet material with magnetic anisotropy in the running direction of the magnetic tape on the downstream side with respect to the running direction of the magnetic tape, and place a magnet material with magnetic anisotropy in the thickness direction of the magnetic tape in the running direction of the magnetic tape. 2. The magnetic erasing head according to claim 1, wherein at least one magnetic erasing head is disposed upstream of the magnetic erase head. (3) A plurality of magnet materials having magnetic anisotropy in the running direction of the magnetic tape arranged downstream with respect to the running direction of the magnetic tape are used. The magnetic erase head according to claim 1 and claim 2, wherein the magnetic erase head is arranged so that the size on the downstream side is not larger than the size on the upstream side with respect to the direction. (4) A non-magnetic material interposed between magnet materials having magnetic anisotropy in the running direction of a plurality of magnetic tapes arranged on the downstream side with respect to the running direction of the magnetic tape; Claims 1 or 2 are arranged so that the thickness of the magnetic tape on the downstream side is not greater than that on the upstream side with respect to the running direction of the magnetic tape.
Magnetic erase head as described in section.