JPH06162460A - Magnetic head - Google Patents

Abstract

PURPOSE:To record signals of a wire frequency band at a high SN ratio by using materials different on the right and left in the sliding direction of the recording medium of the magnetic head for the materials of respective head substrates mounting plural pieces of magnetic head chips onto one head base. CONSTITUTION:Two pieces of the magnetic heads 8, 9 are installed to one head base 21 of a VTR having a rotary cylinder 1. The head chips project from one window of the cylinder by 40mum in the respective head gap 2 parts and are used at and under ordinary temp. and ordinary humidity. The head 8 of the tape contact of the combination magnetic head is set on the preceding side and the head 9 is on the rear side. Both the heads 8, 9 on the preceding side and the succeeding side wear successively by coming into contact with the magnetic tape when the tape of, for example, Co iron oxide is made to travel with the laminated amorphous heads of the VTR of a VHS system for >=100 hours. The good contact of two pieces of the heads 8, 9 with the tape is obtd. at respectively 80% flatness of the output envelope thereof if the radius of curvature of the tape-sliding surfaces of the respective tape heads 8, 9 is assumed to be initially 5mm. The high output in average and the stable output are thus obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head of a magnetic storage device using a rotating cylinder.

[0002]

2. Description of the Related Art In a conventional magnetic recording / reproducing apparatus such as a VTR, a magnetic head protrudes from a cylinder (here, the radius of the cylinder is 31 mm) around which a magnetic tape is wound at a predetermined angle by a predetermined amount. It is fixed to. A combination magnetic head of the above-described conventional magnetic heads will be described below with reference to the drawings.

FIG. 3 shows a magnetic tape sliding surface when a conventional combination magnetic head is projected from a rotary cylinder. Here, a case where two stacked amorphous magnetic heads are provided on one head base will be described.

The head substrate material of this magnetic head sandwiches the magnetic track 5 which is a magnetic material in both the leading head 8 which is the tape entrance side and the rear head 9 which is the tape exit side with respect to the magnetic tape. material of the head substrate 10 which are, for example, utilize those NiO-MgO-TiO _2. Further, the head substrate 10 of the leading head 8 is
As compared with FIG. 3, the upper and lower sides of the magnetic track 5 are made of the same material and naturally have the same hardness, and the substrate of the rear head is also the same, and the head substrate portion of the combination magnetic head is made of the same material and has the same hardness. It is a magnetic head.

The shape of the tape sliding surface of the magnetic head is such that the radius of curvature in the sliding direction is around 9 mm with the head gap 2 as the center.

The positions of the head gaps 2 are arranged so as to be inside each of the chip lengths in the sliding direction of the magnetic head. That is, in the leading head, the length in the sliding direction between the end of the magnetic head on the cylinder window side and the head gap and the length in the remaining sliding direction of the head are longer in the former case. On the contrary, in the head on the rear side, the head gap is centered, and the head closer to the window of the rotary cylinder is longer.

In the magnetic head having such a combination, two head chips are provided from one window of the rotary cylinder of the VTR with respect to the magnetic tape as the magnetic medium, the gap between the leading side head and the gap between the trailing side head on the tape exit side. And are projected by the same amount. In this state, when recording / reproducing at a relative speed between the head and tape of 5.8 m / s or more,
When the sliding curvature radius of each magnetic head is 5 mm, the magnetic tape can be stably and satisfactorily contacted on the two magnetic head gaps in the initial use state of the head.

[0008]

However, when the head is in contact with the magnetic tape for a long time, the sliding surface between the head and the tape is worn and the initial radius of curvature changes from 5 mm to 10 mm or more. As a result, it is difficult for the magnetic tape to stably and satisfactorily contact the head gap, and even if the running system of the magnetic recording / reproducing apparatus is adjusted so that the flatness of the output envelope of the preceding head is 80% or more. , The flatness of the output envelope of the rear head is not 80% or more,
And only an unstable envelope shape is obtained. Therefore, there is a problem that the output of the magnetic head on the rear side is remarkably reduced and the image quality is deteriorated.

Further, in order to obtain high image quality, the flatness of the output envelope of the head must be 90% or more. With the current chip length of the magnetic head in the tape sliding direction, the head is projected from one cylinder window. In that case, there is a problem that a stable envelope shape cannot be obtained and a flatness rate of 90% or more cannot be obtained.

In view of the above, the present invention has a plurality of head chips mounted on one head base in a magnetic head, and all the head chips have a stable output envelope with respect to the magnetic tape and a flatness rate of the envelope. It is an object of the present invention to provide a magnetic head which can obtain 90% or more of the above.

[0011]

In order to achieve this object, the present invention uses a head substrate material of a magnetic head having a plurality of magnetic head chips mounted on one head base on the sliding direction side of a recording medium. The left and right materials are different, and the hardness of the materials in the sliding direction of the recording medium of the magnetic head is different.

Further, when the magnetic head is attached to the rotary cylinder of the recording / reproducing apparatus and the magnetic head is protruded from the window of the rotary cylinder by a certain amount, the hardness of the head substrate of each magnetic head chip is different from that of the cylinder relative to the magnetic head gap. The hardness is reduced nearer to the window.

When the magnetic head is attached to the rotary cylinder of the recording / reproducing apparatus, and the magnetic head projects from the window of the rotary cylinder by a certain amount, the hardness of the head substrate of each magnetic head chip causes the recording medium to slide from the magnetic head gap. In this configuration, the head substrate material of the shorter length in the direction is made the same as the head substrate material of the same length in the longer direction with the head gap of the magnetic head as the center.

[0014]

According to the present invention, when a plurality of head chips are installed on one head base, the hardness of the head substrate is changed in the vicinity of the gap of the installed heads. By reducing the hardness of the head substrate on the side of the rotating cylinder relative to the vicinity, the output envelope of the magnetic head is stabilized, and the flatness of the envelope is 90% or more, so that good contact between the head and tape is obtained. To be

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A magnetic head according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a state of a sliding surface in a magnetic head according to an embodiment of the present invention, and shows an enlarged window portion of a rotary cylinder. In this embodiment, for example, in a VTR having a rotating cylinder 1, as shown in FIG. 2, two magnetic heads 8 and 9 are installed on one head base 21, and head chips are respectively provided from one window of the cylinder. A magnetic head which is projected by 40 microns in the head gap 2 portion and is used at normal temperature and normal humidity will be described.

As shown in the figure, the leading head 8 and the rear head 9 are provided for the tape contact of the combination magnetic head. A configuration in which one magnetic head is installed on each of the two head bases may be used.

A laminated amorphous head is used as the magnetic head. A magnetic tape, which is one of the recording media, for a VHS of a VHS system for a long time of 100 hours or more, for example,
As the Co-type iron oxide tape travels, both the head 8 on the front side and the head 9 on the rear side of the magnetic head come into contact with the magnetic tape, and the head wears. In this case, the radius of curvature of the tape sliding surface of each head is initially 5 mm. While this shape is maintained, as shown in (Table 1), 2
80% flatness of output envelope for each head
And good head-tape contact is obtained.

[0018]

[Table 1]

Note that (Table 1) shows the output envelope flatness rate in each head state. However, when the head wear advances and the radius of curvature changes from 5 mm to 10 mm, the flatness of the output envelope sharply decreases to 60% and the image quality deteriorates. If only one single head is projected from the same rotary cylinder window by the same amount and the initial radius of curvature is 5 mm and the flatness of the output envelope at that time is started from 80%, the head The flatness of the output envelope when the radius of curvature becomes 10 mm due to wear is 75%, which shows that the single head is more likely to obtain stable output than the case of the combination magnetic head.

The flatness here means that when the magnetic head is on the rotating cylinder of the VTR as shown in (Table 1),
The ratio between the minimum value A and the maximum value B of the Rf output envelope from the point where one head starts contacting the tape to the point where it separates is displayed in 100-percentage and defined by the formula A / B * 100%.

The radius of curvature of the sliding surface worn by the head is 10 mm
When it is large like a single magnetic head, it is easier to get good contact between the single head and tape than the combination magnetic head. ,
A relatively stable contact is easily obtained.

Therefore, as shown in FIG. 1, the initial state of the combination magnetic head is set so that the gap between the magnetic heads has a peak. The output is reduced because the apex of is shifted from the head gap. Even if two heads protrude from one rotating cylinder, 2
The number of magnetic heads is such that there is only one magnetic head, that is, the magnetic head is worn so that it can be regarded as a single head. That is, if the head substrate material of the magnetic head near the window of the rotating cylinder is set to be softer than the other head substrate portions and to wear both ends of the magnetic head well, the same wear as in the case of the single head evolves.

However, if the head substrate material is changed in the vicinity of the head gap in one magnetic head, the output is lowered due to uneven wear, and a new problem occurs. Therefore, in the front side head 8 having a boundary line where the material of the head substrate is different, a length equivalent to the distance from the end shorter than the head gap 2 in the sliding direction of the magnetic head is set on the head substrate. The same head substrate material is used up to the longer side. As a result, the influence of uneven wear can be minimized. That is, the material is changed so as to be symmetrical about the head gap 2 with respect to the tape sliding direction.

In this one magnetic head, the head length is set to 200 in the left and right head lengths in the tape sliding direction.
A total length of 400 microns is used for each micron, and NiO-MgO-TiO ₂ which is a conventional head substrate is used as it is, and the material of the remaining head substrate has a Vickers hardness smaller than that of the conventional head substrate. That portion is the head substrate 3 ahead of the gap of the front side magnetic head in FIG. 1 and the head substrate 7 behind the gap of the rear side magnetic head. As a result, the Vickers hardness is small due to the running of the magnetic tape, so that the head tape 4 wears well, and the head substrate 4 behind the gap of the front side magnetic head and the head substrate 6 portion in front of the gap of the back side magnetic head wears too much. However, only the gap of the magnetic head remains and the two heads can be regarded as a large single head even though there are two magnetic heads. After all, the single head can be seen from one window of the rotary cylinder 1. The conditions are the same as or higher than those when the tape is projected, and good contact between the head and the tape can be obtained.

The flatness of the output envelope at this time is 90% for each head for a radius of curvature of 10 mm in the list of the heads of the present embodiment provided with measures against wear as shown in Table 1.
And a stable output can be obtained.

The above description has been made on the case where two magnetic head chips are provided on one head base. However, in the next-generation VTR system, high image quality and miniaturization are advanced, and wide band signals are recorded with high SN ratio and high density. Is required. Therefore, it becomes necessary to arrange a plurality of head chips in a horizontal direction on one head base. Inevitably, the number of combination magnetic heads is three or more, and the same configuration is possible even when the number of head chips is four or more. At that time, if the magnetic heads protruding from one window of the rotary cylinder make it easy to wear the head end side that contacts the recording medium first from each head gap except the last contacting magnetic head, all magnetic heads The output of can be obtained stably.

Further, as an example of the recording medium, there is a head wear during running of a Co-based iron oxide tape, but the magnetic tape is a metal-based vapor deposition tape, a so-called ME tape, a coating type metal tape MP tape, a CoCr tape, etc. The head wear of the magnetic tape as described above can be handled similarly.

[0028]

As described above, according to the present invention, the material of each head substrate having a plurality of magnetic head chips mounted on one head base is different depending on the right and left of the sliding direction of the recording medium of the magnetic head. By using different materials, the hardness of the next generation VTR system will be improved and image quality will be reduced, and even if multiple head chips are installed on one head base, they will be average for all magnetic heads. High output,
Further, a stable output is obtained, and it is possible to easily realize recording of a wide band signal with a high SN ratio and high density.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a state of a sliding surface of a magnetic head according to an embodiment of the present invention.

FIG. 2 is a schematic plan view showing a mounting state of a magnetic head chip of this embodiment.

FIG. 3 is a configuration diagram of a conventional magnetic head

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 rotary cylinder 2 magnetic head gap 3 front side magnetic head gap front head substrate 4 front side magnetic head gap rear head substrate 5 magnetic track 6 rear side magnetic head gap front head substrate 7 rear side Head substrate behind the gap of the magnetic head 8 Leading magnetic head 9 Rear magnetic head

Claims (4)

[Claims] 1. A magnetic head in which a plurality of magnetic head chips mounted on one head base are made of different materials for respective head substrates depending on the right and left of a sliding direction of a recording medium of the magnetic head. . 2. The magnetic head according to claim 1, wherein the material hardness of each head substrate differs depending on the right and left of the sliding direction of the recording medium of the magnetic head. 3. When the magnetic head is attached to a rotary cylinder of a recording / reproducing apparatus and a certain amount of the magnetic head is projected from the window of the rotary cylinder, the hardness of the head substrate of each magnetic head chip is the cylinder relative to the magnetic head gap. 2. The magnetic head according to claim 1, wherein each of the magnetic head substrates closer to the window is made smaller. 4. When the magnetic head is attached to a rotary cylinder of a recording / reproducing apparatus and a certain amount of the magnetic head is projected from the window of the rotary cylinder, the head substrate of each magnetic head chip slides the recording medium from the magnetic head gap. 2. The magnetic head according to claim 1, wherein a substrate material having the same length and quality as the head substrate material for the shorter length in the moving direction is provided also for the longer one with the magnetic head gap as the center.