JPH0240566Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic head equipped with a guard chip.

A stereo recording/reproducing magnetic head 1 equipped with a conventional guard chip will be explained with reference to FIG.
On the front surface 3a of the shield case 3 on which the magnetic tape 2 slides, an R channel magnetic core 4a and an L channel magnetic core 4b are exposed from inside the shield case 3 so as to be flush with the front surface 3a. These cores 4a, 4b
A guard chip 5 made of a rectangular non-magnetic material is also fixed and exposed on the front surface portion 3a.

Among the plurality of tracks of the magnetic tape 2, a track 2c slides on the magnetic core 4a, and a track 2d slides on the magnetic core 4b.

Further, other tracks 2a and 2b of the magnetic tape are sliding on the guard chip 5.

In this way, in the magnetic head 1 which is provided with the guard chip 5 so that the wear caused by sliding of the magnetic tape 2 is uniform on the front surface 3a of the shield case 3, the guard chip 5 made of a non-magnetic material acts as a gap. None, the signals recorded on the tracks 2a and 2b of the magnetic tape 2 are reproduced, and the magnetic flux caused by the signals flows through the shield case 3. Then, the magnetic flux flowing through the shield case 3 leaks to the cores 4a and 4b and is induced in the coils wound around the cores 4a and 4b, producing an output signal, so that the recorded signals on the tracks 2c and 2d of the magnetic tape 2 are reproduced. There is a drawback that a crosstalk phenomenon sometimes occurs due to the above output signal being added as noise.

In view of the above drawbacks, the present invention aims to reduce the crosstalk caused by the guard chip. The structure is characterized in that both sides of the guard chip in the tape running direction are formed non-parallel to the gap of the magnetic core.

Embodiments of the present invention will be described below with reference to FIGS. 2 to 4.

A magnetic tape sliding-side magnetic core 8 is fixed to the magnetic core 7, and a coil bobbin 11 holding a frosting 10 wrapped around a coil 9 is fitted to form an L channel. .
A magnetic core 13 on the sliding side of the magnetic tape is fixed to the magnetic core 12, and a coil bobbin 16, which holds a terminal 15 around which a coil 14 is wound, is fitted to form an R channel. There is. The magnetic cores 7, 8 and 12, 13 of each channel are fixedly held in a core holder (not shown) with a shield plate 17 interposed therebetween, and are fixed in a shield case 18 with a filler 19.

A window 18b for exposing and fixing the magnetic cores 8 and 13 from inside the shield case 18 is bored in the front part 18a of the shield case 18, which serves as the tape sliding surface, and a guard chip 20 is exposed above the window 18b. A recessed portion 18c is formed for fixing.

The guard chip 20 is made of a non-magnetic material such as stainless steel, and is attached to the front surface 1 of the shield case 18.
It is fixed to the concave portion 18c of 8a by spot welding.

The front side 20a and the rear side 20b of the guard chip 20 in the sliding direction A of the magnetic tape 21 are both non-parallel to the gaps 8a, 13a, and are formed in a trapezoidal shape. The magnetic tape 2 is made by sliding the track 2c on the magnetic core 13, the track 2d on the magnetic core 8, and the tracks 2a,
While the guard chip 2b is sliding on the guard chip 5, it is pressed against the front surface 18a of the magnetic head 6 by the tape pad 21 so that the vicinity of the gaps 8a, 13a of the magnetic cores 8, 13 and the entire surface of the guard chip are in pressure contact.

Next, the operation will be described. The magnetic tape 2 slides on the front surface 18a of the shield case 18 while being pressed by the tape pad 21. Even if the magnetic tape 2 is recorded on the tracks 2a and 2b and the non-magnetic guard chip 20 acts as a gap, both sides 20a and 20b of the guard chip 20 on the front and rear sides in the tape sliding direction are , are both formed in a trapezoidal shape so as to be non-parallel to the gaps 8a, 13a, so the azimuth is different from the gaps 8a, 13a, and the gap width l formed by the guard chip 20 is continuous in the width direction B of the magnetic tape 2. is changing. For this purpose, the tracks 2a of the magnetic tape 2 that are reproduced by the guard chip 20,
The reproduction output level of the recording signal 2b is very small.

Therefore, the magnetic flux flowing through the shield case 18 becomes minute, and the magnetic flux leaking to the magnetic cores 8, 13 also becomes minute, thereby reducing the crosstalk phenomenon.

FIG. 5 is a graph showing the crosstalk value between the magnetic head 6 according to the present invention and the magnetic head 1 according to the conventional example.
The reproduction output obtained by reproducing the recorded signal of the track 2c by the magnetic core 13 of the channel is shown. Curve b indicates that the magnetic flux of the recording signal on the tracks 2a and 2b of the magnetic tape 2, which is reproduced by the rectangular guard chip 5 of the conventional magnetic head 1, flows into the shielding case 3 and further leaks to the core 4a of the R channel. The output of the induced crosstalk component is shown.

Curve c indicates a trapezoidal guard chip 2 which is non-parallel to the gap of the magnetic head 6 of the present invention shown in FIGS.
Tracks 2a, 2 of magnetic tape 2 played back at 0
The magnetic flux of the recording signal on b flows into the shield case 18 and further leaks to the magnetic cores 12 and 13 of the R channel, indicating the output of the induced crosstalk component.

The crosstalk values are the differences α and β between the normal reproduction output indicated by a and the outputs of the crosstalk components indicated by b and c.

In this way, for example, when comparing crosstalk at 150Hz, the conventional example had 48 dB of heat, but the present invention has improved by 24 dB to 72 dB.Also, when comparing at 300 Hz, the conventional example had 61 dB of heat, but the present invention has improved crosstalk by 24 dB.
This is an improvement of 76dB and 15dB, and it can be seen that the crosstalk has improved significantly.

This crosstalk value becomes more significant in smaller magnetic heads used in microcassette tape recorders and the like.

6 to 10 show other embodiments, the magnetic head 22 shown in FIG. 6 has a guard chip 23 formed in an inverted trapezoidal shape, and the magnetic head 24 shown in FIG. 7 has a guard chip 25 formed in a circular shape. The magnetic head 26 shown in FIG. 8 has a guard chip 27 shaped like a drum, and the magnetic head 28 shown in FIG. 9 has a guard chip 29 shaped like a parallelogram. In the magnetic head 30 shown in FIG. 10, guard chips 31 are formed in a stepped shape. Similar to the trapezoidal guard chip, these shaped guard chips also have both sides of the guard chip formed non-parallel to the gap, thereby reducing crosstalk that occurs with non-magnetic guard chips.

The guard chip may not only be fixed and exposed in the recess on the front surface of the shield case, but also may be fixed by making the recess into a through hole so that the guard chip is exposed from inside the shield case.

Furthermore, it is not limited to the 2 channel stereotype,
It is also applicable to monaural or multichannel type magnetic heads with three or more channels.

As is clear from the above description, according to the present invention, both sides of the non-magnetic guard chip on the front side and the rear side in the magnetic tape running direction are formed non-parallel to the gap of the magnetic core. Since the signal level of the other tracks that are reproduced by the non-magnetic guard chip on which the other tracks other than the tracks that slide on the core slides becomes extremely small, the crosstalk phenomenon is significantly reduced. Moreover, it is possible to provide a magnetic head in which the crosstalk phenomenon can be significantly reduced regardless of the sliding state between the magnetic tape and the front surface of the magnetic head.

[Brief explanation of the drawing]

Figure 1 is a conventional magnetic head, Figure 2 is a longitudinal cross-sectional view of the magnetic head of the present invention, and Figure 3 is a cross-sectional view of the same.
FIG. 4 is a perspective view of the magnetic head of the present invention, FIG. 5 is a graph showing crosstalk, and FIGS. 6 to 10 are views of other embodiments of the present invention. 2...Magnetic tape, 6...Magnetic head, 7,
8, 12, 13...magnetic core, 8a, 13a...
...Gap, 18...Shield case, 18a...
...front part, 20...guard chip, 20a...front side, 20b...rear side.

Claims (1)

[Claims for Utility Model Registration] A magnetic core and a guard chip made of a non-magnetic material are exposed on the front surface of a shield case on which a magnetic tape having a plurality of tracks slides so as to be substantially flush with the front surface. A magnetic head for recording and reproducing a magnetic tape having a plurality of tracks, wherein different tracks slide on the magnetic core and the guard chip, and the guard chip is arranged on the front side in the running direction of the magnetic tape. A magnetic head in which both sides of the magnetic head and the rear side are formed non-parallel to the gap of the magnetic core.