JPS6331853B2 - - 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. The present invention relates to a combination type magnetic head comprising a head and an erasing head disposed on both sides of the recording/reproducing head and having an erasing gap that covers the tracks on the magnetic medium and limits 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 due to a positioning error in a direction perpendicular to the direction of travel of the magnetic medium. Such interference signals are generated when the recording/reproducing gap (main gap) of the magnetic head is not precisely positioned over the track to be reproduced on the magnetic medium, but partially covers the track on the side. This can occur when playing back a recording on a track, or when the previous recording is not completely erased when recording on a 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. recent years,
With the demand for smaller magnetic recording and reproducing devices,
Track density is also becoming higher due to 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 at the magnetic medium contact surface 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 a track and which is easy to manufacture.

For this purpose, the combination type magnetic head according to the present invention includes an erasing head disposed on both sides of a recording/reproducing head with a non-magnetic material interposed therebetween, the non-magnetic material part serving as a first erasing gap, and the erasing head A second erasing gap is formed in a curved manner and extends parallel to the magnetic medium and perpendicular to the running direction of the magnetic medium, and is connected to the first erasing gap in a curved shape.

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 a combination magnetic head according to one embodiment of the present invention, that is, the contact surface with the magnetic tape, and FIG. 4 is a schematic diagram of another embodiment. The recording/reproducing head 5 has the same structure as shown in FIGS. 1 and 2, and has a recording/reproducing gap 6 extending perpendicularly to the running direction of the magnetic tape (indicated by the arrow). Erasing heads 1 and 2 are arranged on both sides of the recording/reproducing head 5 with a non-magnetic material such as resin, glass or titanium foil interposed therebetween. This non-magnetic material forms first erasing gaps 9, 10 parallel to the running direction of the magnetic tape between the recording/reproducing head 5 and the erasing heads 1, 2. The non-magnetic material is sandwiched between the erasing heads 1 and 2 over the entire joint surface of the recording/reproducing head 5 and the erasing heads 1 and 2.
Each of the erasing heads 1, 2 has a second erasing gap 7, 8 extending perpendicularly to the running direction of the magnetic tape approximately midway therebetween. This second
The erase gaps 7, 8 are connected to the first erase gaps 9, 10 in a curved manner. The embodiment shown in FIG. 3 is an example in which the second erasing gaps 7, 8 are curved convexly in a direction opposite to the magnetic tape traveling direction and are connected to the first erasing gaps 9, 10. On the other hand, in the embodiment shown in FIG. 4, the direction of the curved shape is reversed, that is, the magnetic tape is curved in a convex manner in the direction of travel of the magnetic tape (in the direction of the arrow). Both have first and second elimination gaps 9, 10 and 7, 8.
is formed on the downstream side of the recording/reproducing gap 6 in the magnetic tape running direction.

FIG. 5 is a schematic perspective view of the above-mentioned erasing heads 1 and 2 actually assembled into the recording/reproducing head 5. As shown in FIG. In this embodiment, a reinforcing material 15 made of a non-magnetic material such as titanate or barium titanate porcelain is bonded to a part of the recording/reproducing head 5. A rear core 13 is attached to each of the sides of the erasing heads 1 and 2, and a separate erasing head core 11 is combined and joined between the erasing heads 1 and 2 on both sides. Erasing coils 14 and 12 are attached to these cores 13 and 11, respectively. The core 11 serves as a magnetic circuit between the erasing heads 1 and 2 on both sides, and current may be passed through the erasing coil 12 independently, or each erasing coil of each erasing head 1 and 2 itself may be connected. 14 in series or parallel to supply the erase current from a common power supply.

In a magnetic head having such a shape, the first erase gaps 9, 10 are parallel to the running direction of the magnetic tape during recording and reproduction, and the erase heads 1, 2 themselves extend perpendicular to the magnetic tape running direction. Since the direction of the magnetic flux in the curved connected portion of the second erasing gaps 7 and 8 is different from the direction of the magnetic flux in the recording/reproducing gap 6, the erasing magnetic flux interferes with the magnetic circuit of the recording/reproducing head 5. It rarely occurs. Further, as shown in FIG. 3, the width of the first and second erase gaps is t, but the width of the erase track is as wide as T. Although the width of the erase track is large, the actual width of the erase gap is narrow, so that the effect of the erase magnetic flux on the recording/reproducing track is small. Since the width t of the erase gap is narrow, the erase current can be small and the efficiency is also excellent. The transition in the recording/reproducing track is much smaller than in a structure in which the erasure gap is perfectly perpendicular to the recording/reproducing gap 6. Further, first erase gaps 9, 10 parallel to the magnetic tape running direction are provided.
extends over the entire length of the erasing heads 1 and 2 in the magnetic tape running direction, and from the middle part, the second erasing gaps 7 and 8 are connected to the erasing gaps 9 and 10 in a curved shape and are perpendicular to the magnetic tape running direction. The structure that extends in the direction can provide higher erasing efficiency than the straddle type structure shown in FIG. The combination type magnetic head of the present invention is much easier to manufacture than the tunnel erase type head shown in FIG.

[Brief explanation of the drawing]

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 FIG.
The figure is a schematic diagram similar to FIG. 3 according to another embodiment of the present invention, and FIG. 5 is a schematic perspective view of a combination type magnetic head of the present invention. 1, 2... Erasing head, 5... Recording/reproducing head, 6... Recording/reproducing gap, 7, 8... Second erasing gap, 9, 10... First erasing gap, 12, 14... Erasing. Coil, 15...Reinforcement material.

Claims (1)

[Claims] 1. In a magnetic head that combines a recording/reproducing head and an erasing head, the erasing head is arranged on both sides of the recording/reproducing head with a non-magnetic material interposed therebetween, the non-magnetic material part is used as a first erasing gap, and the erasing head A combination magnetic field characterized in that a second erasing gap is formed in parallel to the magnetic medium and extends in a direction perpendicular to the running direction of the magnetic medium, and is connected to the first erasing gap in a curved shape. Head.