JPH0118494B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic head that integrally combines a recording/reproducing head and an erasing head, specifically a recording/reproducing head having a main gap on the front surface for recording and reproducing, and a recording/reproducing head having a main gap for performing recording and reproducing. The present invention relates to a combination magnetic head comprising an erasing head and an erasing gap disposed on both sides of the head to cover the tracks on the magnetic medium and define the tracks to be recorded or recorded.

Generally, in a magnetic recording device, a magnetic drum,
When reproducing a recording on a magnetic medium such as a magnetic disk or magnetic tape, a disturbance signal may be generated based on positioning errors in a direction transverse to the direction of travel of the magnetic medium. In this way, the interference signal is generated when the recording/reproducing gap (main gap) of the magnetic head is not precisely positioned on the track to be reproduced on the magnetic medium, but partially covers the side tracks.
This may occur when the recording on the track on this side is played back, or when the previous recording was not completely erased when recording on the track. In order to prevent interference signals due to positioning errors of the magnetic head, magnetic heads of the type in which erasing heads are arranged on both sides of the recording/reproducing head have been known. One erase head covers the track to define one side of the main track, and the other erase head covers the other side of the same main track. During a recording operation, both the recording/reproducing head and the erasing head are energized, thereby erasing a predetermined width on both sides of the track simultaneously with the recording operation. The width to be erased by the erasing head depends on the accuracy of the positioning mechanism for positioning the magnetic head on a given track. In recent years, with the demand for miniaturization of magnetic recording/reproducing devices, track densities have been increasing for high-density recording.

As such combination type magnetic heads, there are a tunnel erase type magnetic head shown in FIG. 1 and a straddle erase type magnetic head shown in FIG. 2, each of which has advantages and disadvantages. In the tunnel erase system shown in FIG. 1, erase gaps 3 and 4 of erase heads 1 and 2 extend in a direction perpendicular to the running direction of the magnetic medium.
Note that the arrows indicate the running direction of a magnetic medium, such as a magnetic tape, during recording and reproduction. The recording/reproducing gap 6 of the recording/reproducing head 5 is formed at a position shifted upstream from the erasing gaps 3, 4 in the traveling direction of the magnetic medium, but in this system, the recording/reproducing gap 6 and the erasing gaps 3, 4 are both parallel to each other. It is. The advantage of this structure is that it is somewhat easier to manufacture than the straddle type shown in FIG. 2, which will be described later.
However, in this structure, the magnetic flux generated in the effective gap of the erasing heads 1 and 2 affects the magnetic flux in the effective gap 6 caused by the recording/reproducing head 5, and furthermore, placing the erasing gaps 3, 4 in this position does not affect the recording/reproducing gap. This is inappropriate when reproducing a signal recorded by 6. Since the magnetic fluxes of both the erasing heads 1, 2 and the recording/reproducing head 5 are in the same direction, mutual interference occurs between these magnetic fluxes. Furthermore, it is difficult to concentrate the erasing magnetic flux by the erasing gaps 3 and 4 on the side edges of the recording/reproducing track. On the other hand, in the straddle erase type magnetic head shown in FIG. 2, the erasing heads 1 and 2 are arranged on both sides of the recording/reproducing head 5 with a gap-forming non-magnetic material such as resin, glass, titanium foil, etc. The erasing gaps 3 and 4 extend parallel to the running direction of the magnetic medium on the front surface of the magnetic head, and are perpendicular to the gap 6 of the recording/reproducing head 5. The magnetic flux directions of the recording/reproducing gap 6 and the erasing gaps 3, 4 are no longer in the same direction, so that the influence of the magnetic flux of the erasing gap on the recorded signal and interference with the magnetic circuit of the recording/reproducing head is minimized. The advantage of this structure is that it is possible to form a strong core as an erase head, and the magnetic head itself is relatively easy to manufacture. However, the structure shown in Figure 2 is
A major difficulty arises when the track to be regenerated has a narrow width, ie, a high density track. In practice there are always transitions on both sides of the erased track.
This portion extends into the recording/reproducing track a distance from the outer edge of the recording/reproducing track at least equal to the width of the erasure gap adjacent the recording/reproducing track. In this transition, the magnetization distribution of the recorded track gradually decreases towards the edges. This transition on both sides of the recording/reproducing track has a very undesirable effect on the relative strength of the recorded signal.

The present invention utilizes the advantages of the above-mentioned two types of combined magnetic heads while eliminating their disadvantages, and the width of the transition region can be recorded and reproduced by a narrow erase gap even in the presence of positioning errors. It is an object of the present invention to provide a combination type magnetic head which can be made negligibly small compared to the width of the track and which is easy to manufacture.

In a magnetic head that combines a recording/reproducing head and an erasing head, the present invention provides non-contact elements on both sides of the recording/reproducing head that act as first erasing magnetic gaps extending perpendicularly to the magnetic gap of the recording/reproducing head. An erasing head having a second erasing magnetic gap approximately parallel to the magnetic gap of the recording/reproducing head is arranged through a magnetic material, and the second erasing magnetic gap formed by the erasing head itself and the non-magnetic material A pair of T's are formed on both sides of the recording/reproducing head by the first erasing magnetic gap formed between the erasing head and the recording/reproducing head.
It forms a glyph erasing gap.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 is a schematic diagram of the front portion of the combination type magnetic head according to the embodiment of the present invention, that is, the magnetic tape running surface. The recording/reproducing head 5 is shown in FIGS. 1 and 2.
The structure is the same as that shown in the figure, and a recording/reproducing gap 6 is formed extending perpendicularly to the running direction of the magnetic tape (indicated by the arrow). As shown in FIGS. 3 and 4 a and 4b, a second erasing magnetic gap is formed on each side of the recording/reproducing head 5 through non-magnetic plates 7 and 8 for forming a first erasing magnetic gap. A pair of erasing heads 1 and 2 having magnetic gaps 9 and 10 are arranged, and these erasing heads 1 and 2 are connected to a connecting core at the front or rear end in the magnetic tape running direction and away from the magnetic tape running surface. (rear core)
11, and a coil 12 is attached to this connecting core 11. Further, a rear core 13 is attached to the side of each erasing head 1, 2, and a coil 14 is attached to this core as well. The coil 12 and each coil 14 may be connected independently, in series, or in parallel from a power source. The second erasing magnetic gap 9, 10 of the erasing head 1, 2 itself extends parallel to the recording/reproducing gap 6 of the recording/reproducing head 5. With this structure, the magnetic head as a whole has a recording/reproducing gap 6 perpendicular to the running direction of the magnetic tape and a pair of T-shaped erasing gaps perpendicular to and parallel to the running direction of the magnetic tape. In the first erasing magnetic gap in the portion of the non-magnetic plates 7 and 8 adjacent to the recording/reproducing head 5 in this erasing gap, the direction of the magnetic flux is the same as that of the recording/reproducing gap 6.
Since the direction of the magnetic flux in this part is different from that of the magnetic flux, the magnetic flux in this part has little interference with the magnetic circuit of the recording/reproducing head. Since the magnetic flux for erasing is concentrated on the sides of the recording/reproducing head, high erasing efficiency can be obtained.
Furthermore, manufacturing of the magnetic head is much easier than that of the tunnel erase method shown in FIG. 1, and the strength of the entire magnetic head can also be increased.

[Brief explanation of drawings]

FIGS. 1 and 2 are schematic diagrams showing an example of a conventional combination type magnetic head, FIG. 3 is a schematic diagram of a combination type magnetic head according to an embodiment of the present invention, and FIGS. FIG. 2 is a perspective view schematically showing the internal structure of the combination type magnetic head according to FIG. 1, 2... Erasing head, 5... Recording/reproducing head, 6... Recording/reproducing gap, 7, 8... Non-magnetic plate, 9, 10... Second erasing magnetic gap of the erasing head itself.

Claims (1)

[Claims] 1. In a magnetic head that combines a recording/reproducing head and an erasing head, a non-magnetic material is provided on both sides of the recording/reproducing head to act as a first erasing magnetic gap extending perpendicularly to the magnetic gap of the recording/reproducing head. An erasing head having a second erasing magnetic gap substantially parallel to the magnetic gap of the recording/reproducing head is disposed through the recording/reproducing head, and the second erasing magnetic gap is formed by the erasing head itself and the non-magnetic material portion. A combination type magnetic head, characterized in that a pair of T-shaped erasing gaps are formed on both sides of the recording/reproducing head by the erase head and the first erasing magnetic gap between the recording/reproducing head.