JPH08321008A - Rotating magnetic head and rotating drum - Google Patents

Abstract

(57) [Abstract] [Purpose] To eliminate the loss of RF signal due to the spacing of the tape from the vicinity of the center of the rotating drum to the vicinity of the outlet, and to obtain a rotating magnetic head capable of ideal digital recording operation. A ratio of a radius of curvature Rx in the longitudinal direction of the rotary magnetic head 2 to a radius of curvature Ry in the thickness direction of the head is Ry / R.
It was set to x ≦ 0.17.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording / reproducing apparatus, for example, a consumer video tape recorder (hereinafter referred to as VTR) which is recorded / reproduced by a helical scan method by a digital signal.
The present invention relates to a rotary magnetic head suitable for application to a device) and a rotary drum having the rotary magnetic head.

[0002]

2. Description of the Related Art FIG. 4 is a plan view showing a conventional rotary drum having a rotary magnetic head of this type and a tape helically wound around the rotary drum.

The rotary drum indicated by reference numeral 1 is a so-called two-head rotary drum in which two magnetic heads 2 and 2 are arranged in an angle range of 180 °. A magnetic tape 3 as a recording medium is wound around the rotating drum 1 via a supply side tilt guide 4 from the drum inlet side to the drum outlet side at a winding angle θ, and the magnetic tape 3
Goes to a pinch roller (not shown) that drives the tape through the winding-side tilt guide 5.

Here, the tape 3 wound around the rotary drum 1 is used for recording and reproducing operations of digital signals by helical scan scanning by the magnetic head 2. Generally, the tape 3 is rotated in the recording and reproducing apparatus as described above. There is a problem that a signal is lost near the center of the drum 1 due to the spacing phenomenon of the tape with respect to the magnetic head 3.

Explaining the cause of this signal loss, when the tape 3 is wound around the rotary drum 1, the tape has tension in itself, so that the so-called "Euler system" is applied from the inlet to the outlet of the rotary drum. As a result, the tape tension increases. That is, the tape gradually comes into strong pressure contact with the magnetic head from the inlet of the rotary drum toward the outlet thereof.

[0006] This is further detailed _{explanation, θ 1 (= θ / 3} ) an inlet near the rotary drum 1 in FIG. 4, near the center _{θ 2 (= θ / 3)} , the vicinity of the outlet θ ₃ (= θ / 3)
And

FIG. 5 shows the contact state of the tape with the magnetic head 2 near the drum entrance θ ₁ . In the vicinity of the drum entrance, the pressure contact force between the rotary drum 1 and the tape is small,
Moreover, since the air film a ₁ generated between the rotary drum 1 and the tape 3 is also large, the tape 3 uniformly contacts the entire contact width W of the magnetic head 2, that is, the spacing phenomenon does not occur, that is, In the RF signal waveform diagram shown in FIG. 4, an ideal state in which no signal loss occurs is obtained.

FIG. 6 shows the contact state of the tape with the magnetic tape 2 near the center of the drum θ ₂ . Near the center of the drum, the pressure contact force between the rotating drum 1 and the tape is large,
Moreover, since the air film a ₂ generated between the rotary drum 1 and the tape 3 is small, the tape 3 which is an elastic body comes into contact with only the edge portion of the magnetic head 2 and causes a spacing d in the central portion of the head. . Therefore, in the RF signal waveform diagram shown in FIG. 4, a signal loss occurs. It has been found that a signal loss due to spacing is further generated near the drum outlet θ ₃ .

The signal loss as described above greatly affects the tape tension, the tip shape of the magnetic head 2, the head contact width, and the head protrusion amount.

For example, considering the head contact width with reference to FIG. 7, when the head has the same curvature in the width direction and the contact width is W ₂ > W ₁ , the spacing is d ₁ <d ₂ . In other words, the smaller the head contact width, the less the loss of signals.

When the head protrusion amount is considered with reference to FIG. 8, d ₁ <d ₂ when the head protrusion amount is hp ₁ <hp ₂ . That is, it can be said that the smaller the head protrusion amount, the less the loss of signals.

The present invention has been made in order to solve the above-mentioned problems, and eliminates the loss of the RF signal due to the spacing of the tape from the vicinity of the center of the rotating drum to the vicinity of the outlet, and ideal recording / reproducing operation. It is an object of the present invention to obtain a rotary magnetic head capable of achieving the above and a rotary drum having the magnetic head.

[0013]

In order to achieve the above-mentioned object, the rotary magnetic head according to the present invention has a ratio of a radius of curvature Rx in the longitudinal direction of the rotary magnetic head to a radius of curvature Ry in the head thickness direction of Ry / Rx. It is set to ≦ 0.17.

Further, in the rotary drum according to the present invention, the rotary magnetic head provided in the rotary drum has a ratio of the curvature radius Rx in the longitudinal direction of the head to the curvature radius Ry in the thickness direction of the head as Ry.
The rotary magnetic head is set so that /Rx≦0.17.

[0015]

With the rotary magnetic head of the present invention constructed as described above, recording / reproduction is performed in a state where the tape is in contact with the magnetic head over the entire head contact width and no spacing occurs even when the tape is in strong contact with the magnetic head. You can take action.

Further, the rotary drum of the present invention can perform the recording / reproducing operation without causing spacing due to the contact of the tape over the entire width of the head contact from near the center of the drum to near the outlet of the drum.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A rotary magnetic head and a rotary drum according to the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a rotary magnetic head of this example, showing a magnetic head applied to a consumer video tape recorder which performs recording / reproducing operation by a digital signal, and FIG. 2 shows a state where a tape hits the magnetic head. Therefore, the same parts as those in the configuration of the conventional example described with reference to FIGS. 5 and 6 are denoted by the same reference numerals, and the duplicate description will be omitted.

According to the present invention, as a means for eliminating the loss of the RF signal due to the spacing of the tape from the vicinity of the center of the rotating drum to the vicinity of the outlet, and performing an ideal recording / reproducing operation, the head length of the rotating magnetic head is increased. It was noted that this can be achieved by setting the ratio of the radius of curvature in the direction to the radius of curvature in the head thickness direction to a predetermined value.

Therefore, in the present invention, the radius of curvature of the rotary magnetic head in the longitudinal direction of the head is Rx, the radius of curvature in the thickness direction of the head is Ry, and the digital signal VT is used.
Ry is used and Ry is set under the following setting conditions.
Tests were performed with various ratios of / Rx.

Rotational magnetic head contact width W ... 55 to 80 μm Rotational magnetic head protrusion amount hp ... 14 to 23 μm Rotation drum diameter: 21.7 mm (rotation) Number: 150 rps) Tape speed: 18.812 mm / s Recording signal: 10 Mhz Track pitch: 10 μm Tape: Evaporated metal ebonite tape Width: 6.35 mm Tape thickness: 7 μm Stiffness ratio of tape:・ 0.5 to 0.9 (mechanical strength in the longitudinal and width directions of the tape)

FIG. 3 shows the test results of the Ry / Rx ratio of the magnetic head and the contact (%) of the tape with the head based on the above setting conditions.

According to this, when the Ry / Rx ratio of the magnetic head is about 0.2 or more, the result is obtained that the contact of the tape with the magnetic head is lowered and the signal is abruptly dropped. On the other hand, when the Ry / Rx ratio is 0.17 or less, the tape hits the magnetic head in an ideal state,
The result was that no signal loss occurred.

In the test, the contact width of the rotary magnetic head, which is an important factor of the setting conditions, was 55 μm and 80 μm, and the test data of FIG. 3 showed the case of 80 μm. 80 μm
There was no difference from the case. Further, the amount of protrusion hp of the rotary magnetic head was performed for three types of 14 μm, 19 μm, and 23 μm in the test, and the test data of FIG. 3 shows the case of 23 μm, but similar results are obtained in the case of 14 μm and 19 μm. It was

Therefore, the present invention uses the Ry / Rx of the magnetic head.
By setting the ratio to ≦ 0.17, the loss of the RF signal due to the spacing of the tape from the vicinity of the center of the rotating drum to the vicinity of the outlet can be eliminated as shown in FIG. 2, and an ideal digital signal recording operation can be performed. It was possible to obtain a rotating magnetic head that did.

The present invention is not limited to the embodiments described above and shown in the drawings, and various modifications can be made without departing from the scope of the invention.

For example, the magnetic head of the present invention is provided in various sets of rotary drums, and when the magnetic drums are mounted on a digital VTR device and used, magnetic tape or head molding in accordance with it may be performed. The invention also defines these rotary magnetic heads after molding.

Further, the rotary magnetic head and the rotary drum of the present invention are extremely suitable for being applied to a consumer VTR device in which recording and reproducing operations are carried out by a helical scan system by a digital signal.

[0028]

As described above, in the rotary magnetic head of the present invention, the ratio of the radius of curvature Rx in the longitudinal direction of the rotary magnetic head to the radius of curvature Ry in the head thickness direction is Ry / Rx.
By setting ≤0.17, it is possible to perform the recording / reproducing operation in a state where the tape is in contact with the magnetic head over the entire head contact width and no spacing occurs even when the tape is in strong contact with the magnetic head. effective.

In the rotary drum of the present invention, the rotary magnetic head is provided with a rotary magnetic head in which the ratio of the radius of curvature Rx in the longitudinal direction of the head to the radius of curvature Ry in the thickness direction of the head is set to Ry / Rx≤0.17. As a result, the recording / reproducing operation can be performed without causing spacing due to the contact of the tape over the entire width of the head contact even in the vicinity of the center of the drum to the vicinity of the outlet of the drum.

[Brief description of drawings]

FIG. 1 is a perspective view of a rotary magnetic head of the present invention.

FIG. 2 is an explanatory diagram of a state where a tape hits a magnetic head of the present invention.

FIG. 3 is a diagram showing test results of the present invention.

4A and 4B are a plan view and an RF signal waveform diagram of a winding state of a conventional rotary drum and a tape.

FIG. 5 is an explanatory diagram of a contact state between a magnetic head and a tape in the vicinity of a conventional rotary drum entrance.

FIG. 6 is an explanatory diagram of a contact state between a magnetic head and a tape in the vicinity of the center of a conventional rotating drum.

FIG. 7 is an explanatory diagram of a spacing phenomenon when the contact width is different.

FIG. 8 is an explanatory diagram of a spacing phenomenon when the magnetic head protrusion amounts are different.

[Explanation of symbols]

 1 rotating drum 2 rotating magnetic head 3 magnetic tape Rx radius of curvature in longitudinal direction of magnetic head Ry radius of curvature in thickness direction of magnetic head W width per head hp head protrusion amount

Claims (4)

[Claims] 1. A rotary magnetic head for a recording / reproducing apparatus, wherein the ratio of the radius of curvature Rx in the longitudinal direction of the rotary magnetic head to the radius of curvature Ry in the thickness direction of the head is Ry / Rx ≦ 0.
A rotary magnetic head characterized by being set to 17. 2. The rotary magnetic head according to claim 1, wherein the rotary magnetic head is applied to a consumer video tape recorder which records and reproduces by a digital signal. 3. A rotary drum of a recording / reproducing apparatus, wherein a rotary magnetic head provided on the rotary drum has a radius of curvature Rx in a head longitudinal direction and a radius of curvature Ry in a head thickness direction.
A rotary drum comprising a rotary magnetic head having a ratio of Ry / Rx ≦ 0.17. 4. The rotary drum according to claim 3, wherein the rotary drum is applied to a consumer video tape recorder which records and reproduces by a digital signal.