JPH09237403A - Head, rotary head device including the same, and recording / reproducing device including the rotary head device - Google Patents

Abstract

(57) Abstract: A double azimuth head having different azimuth angles and adjacently arranged with a predetermined height deviation in the rotational direction, and a good head due to an increase in contact surface pressure in the head gap portion. Achievement of contacts and reduction of changes in head contact performance over time. SOLUTION: The radius of curvature of the heads 1 and 2 in the rotation direction with respect to the tape 13 is set to the first regions 10 and 2 including a gap.
A radius of curvature R1 forming 0 and a radius of curvature R2 forming second regions 15 and 25 adjacent to the first regions 10 and 20.
And a connecting portion P of the arc having the radius of curvature R1 and the arc having the radius of curvature R2 is a common tangent line connecting the arc forming the outer circumference of the rotary drum to the circle formed by R1. Positioned in the direction of the head adjacent to the contact point Q on R1, the relationship between the radius of curvature of the two regions is R
Set 1> R2. Since the contact area of the tape can be decreased, the contact surface pressure between the gap and the tape can be increased, and a good head contact state can be obtained, and the contact area with the tape is wide to some extent, so the contact performance changes over time. Shrink.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary head type magnetic recording / reproducing apparatus having a double azimuth head such as a VTR or DAT, and a head used in the magnetic recording / reproducing apparatus.

[0002]

In recent years, in magnetic recording / reproducing devices such as VTRs and DATs, a so-called guard bandless recording system, in which a gap called a guard band is not provided between adjacent tracks in order to increase the recording density, has recently been adopted. It is the mainstream. In guard bandless recording, the head gap angle, so-called azimuth angle, is made different between two heads that record or reproduce adjacent tracks.
The principle of reducing crosstalk from adjacent tracks due to azimuth loss during playback is adopted. Further, in order to realize high-density recording, the recording signal is set to a high frequency, the signal of this wide band is divided, and two heads having different azimuth angles (called double azimuth heads) arranged close to each other are used to separate two signals. This is a method of simultaneously recording or reproducing tracks. This is because when recording a signal of the same capacity without division, it is necessary to double the recording frequency, which causes output degradation due to high frequency loss. Also,
There is also a method of rotating the rotary drum at a double speed, but this causes problems such as deterioration of head contact performance and head life. Further, in the above-mentioned double azimuth head, there is a problem that the setting range of the head where a good head output is obtained is narrow. That is, the condition for stabilizing the contact between the head and the tape, that is, the so-called head contact stabilization is narrowed.

In order to solve such a problem, in the conventional technique, for example, in Japanese Patent Laid-Open No. 2-149908, it is possible to optimize the width of cores on the opposite sides of two heads by designating the widths of cores on opposite sides of the two heads. A technique for obtaining excellent head contact performance is disclosed. When recording or reproducing two tracks at the same time by the double azimuth head, between the head that precedes the head (leading head) and the head that is adjacent to the rear of the head (trailing head) in the rotating direction of the rotary drum. In addition, it is necessary to provide a predetermined step in a direction orthogonal to the rotation direction of the rotary drum so as to form a predetermined track width. In this case, in a small system such as 8 mm or DAT, the diameter of the rotary drum is φ40.
Since the diameter is as small as mm or φ30 mm, it is necessary to arrange a pair of heads arranged on the drum in close proximity as a leading head and a trailing head. For example, the track pitch is 15μ
In the case of m, the step difference between the leading head and the trailing head is about 15 μm, and the distance between the gaps of the leading head and the trailing head is 1 mm or less in order to eliminate the time lag of the signal of each channel. Had to do.

When the leading head and the trailing head are arranged close to each other as described above, the head gap is not located at the apex of the tape enclosing the head as in the case of the single head, and the contact between the tape and the head is not achieved. Since the width is wider than that of the single head, the surface pressure at the gap position is low, and it is difficult to secure good head contact performance. Further, the deformation of the tape by the preceding head affects the succeeding head, and the contact performance between the succeeding head and the tape deteriorates. In particular, on the drum output side, which is the upstream side of the tape, the head scans the upper end of the tape, but since there is no restriction at the upper end edge of the tape, the trailing head is easily affected by the deformation of the tape by the preceding head. Therefore, the head contact performance changed depending on the position of the head gap and the shape of the head tip. Therefore, there is a problem in that the optimum head contact performance cannot be stably obtained by specifying only the core width as disclosed in the above-mentioned prior art.

Here, when the protrusion amounts of the heads are the same,
When the tape tension is the same, the head pressing force of the tape is constant. However, the contact length between the head and the tape changes depending on the shape of the tip of the head, particularly the radius of curvature in the rotation direction. Therefore, by decreasing the radius of curvature of the head, the contact length of the tape can be shortened, and by increasing the contact pressure between the head and the tape, the head touch can be stabilized. However, decreasing the radius of curvature of the head and increasing the contact pressure of the tape improves the contact performance, but it causes the problem of increasing the wear of the head and weakening the change over time.

Therefore, the present invention is provided with a rotary magnetic head device equipped with a double azimuth head having optimum head contact performance and capable of reducing the temporal change of the head contact performance, and a rotary magnetic head device. A recording / reproducing device is provided.

[0007]

In order to achieve the above object, a rotary head device of the present invention comprises a head composed of a head gap and a head core, a rotary drum to which the head is attached, and a rotary drum rotatably supported. And a fixed drum, and the head is composed of a pair of heads including a first head and a second head. The first head and the second head have a predetermined gap in the rotation direction of the rotary drum. The heads are arranged side by side with different azimuth angles from each other with a predetermined step in the direction orthogonal to the rotation direction of the rotary drum, and the first head and the second head have a head gap. A first region and a second region adjacent to the first region via a connecting portion,
The region is formed by an arc having a radius of curvature in the rotation direction as a dimension R1 and the second region is formed as an arc having a radius of curvature in the rotation direction as a dimension R2, and basically has a relationship of radius of curvature R1> radius of curvature R2. To have.

For example, the range of the radius of curvature R1 of the first area is set to 6 ≦ R1 ≦ 10 mm and the range of the radius of curvature R2 of the second area is set to 4 ≦ R2 ≦ 6 mm, or the radius of curvature of the first area is set. The range of R1 is set to 6 ≦ R1 ≦ 9 mm, the range of curvature radius R2 of the second region is set to 5.4 ≦ R2 ≦ 5.6 mm, and the range of curvature radius R1 of the first region is 7 ≦ R1 ≦
9 mm, and the radius of curvature R2 of the second region is set to about 5.5 mm.

In the rotary head device, the length from the contact end of the tape in the first region to the head gap to the head gap in the direction perpendicular to the center lines of the first head and the second head is set to the tape and the head. When the contact length L is L ≦ 400 μm, or the lower limit is 150 μm, 200 μm, or 300 μm, the radius of curvature R1 of the first region and the radius of curvature R2 of the second region are set. Further, when the head has a contact area with the tape from the contact end portion with the tape in the first area to the head gap, the height change a of the contact area is a ≦ a.
The radius of curvature R1 of the first region and the radius of curvature R2 of the second region are set so as to be 0.036. When using a tape with a smaller thickness, 0.015 ≤ a ≤ 0.0
6 is satisfied, and when it is used also for a thick tape, 0.02 ≦ a ≦ 0.036 is satisfied, where a = N / M N: Head displacement in the direction of the centerline between adjacent heads in the contact area. M: Displacement of the head in the direction orthogonal to the center line between adjacent heads in the contact area. And so on.

In the recording / reproducing apparatus of the present invention, a tape is wound around the rotary head device at a predetermined angle, and at least:
It is provided with a configuration in which information is recorded on a tape or a signal is reproduced from the tape by rotating at a rotation speed of approximately 1800 rpm. Further, the tape wound around the rotary head device forms a predetermined tape running path, and the tension T in the longitudinal direction of the tape at the entrance side of the rotary head device when recording or reproducing is 10 gf≤T. The configuration is such that ≦ 15 gf is set.

The rotary head device of the present invention and the head of the recording / reproducing device have a first region having a head gap,
A second region adjacent to the first region via a connecting portion, and the first region has a radius of curvature in the rotation direction as a dimension R1;
The second region is formed by an arc having a radius of curvature R2 in the rotation direction, and has a relationship of radius of curvature R1> radius of curvature R2. The length from the contact portion of the tape to the head gap in the first region is When the contact length L between the tape and the head is L, the radii R1 and R2 are set so that L ≦ 400 μm, or the contact area between the tape contact portion and the head gap in the first area is the contact area with the tape. At this time, a configuration is basically provided in which the radii R1 and R2 are set so that the height change a of the contact region is a ≦ 0.036.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a double azimuth head and a rotary head device in a recording / reproducing apparatus of the present invention will be described below with reference to the drawings. First, the structure of the double azimuth head will be described. 1 is a top view illustrating a double azimuth head, FIG. 2 is a front view of the head as seen from a tape sliding surface, and FIG. 3 is a partially enlarged view showing a state in which the head is attached to an upper rotary drum. The head mounted on the upper rotary drum 7A has a trailing head 1 that comes into contact with the tape later and a preceding head 2 that comes into contact with the tape first. The trailing head 1 includes a head gap 1A and a head core 1B, and the leading head 2 includes a head gap 2A and a head core 2B. The leading head 2 and the trailing head 1 are arranged side by side so that their head gaps 2A, 1A have a predetermined distance.

Each of the heads 1 and 2 is composed of two areas having different curvatures, a first area 10 and 20 and a second area 15 and 25. First area 10, 20
Is an area formed by an arcuate surface having a radius of curvature R1, and the second areas 15 and 25 are areas formed by an arcuate surface having a radius of curvature R2. The first regions 10 and 20 are regions including the head gap portions 1A and 2A, and
The regions 15 and 25 are arranged adjacent to the first regions 10 and 20.

First regions 10, 20 having a radius of curvature R1
And a portion connecting the second regions 15 and 25 having the radius of curvature R2 is shown as a connecting portion P in the top view. Further, the contact end portion between the tape and the head is defined as a contact point Q. Here, in the present invention, the connection portion P is set by setting the outer peripheral surface of the first region 20 having the gap portion 2A of the preceding head 2 from the peripheral surface of the upper rotary drum 7A and an extension line 60 of this outer peripheral surface (FIG. When a tangent line 14 is drawn toward the circular arc-shaped dotted line in 1) and a contact point with the outer peripheral surface of the preceding head 2 is a contact point Q ', the connecting portion P is adjacent to the contact point Q'. The position is set to be close to a certain trailing head 1. Similarly, in the trailing head 1, the connecting portion P is arranged at a position close to the leading head 2. That is, the contact Q ′ is arranged to be on the extension line 60. Therefore, when the tape is actually wound, the Q is the same as the P.

The heads 1 and 2 are arranged symmetrically with respect to the center line V and are configured to rotate in the direction of arrow 3 (see FIG. 2). As the head rotates, the head gaps 1A and 2A record tracks on the tape or reproduce the recorded tracks. The head cores 1B and 2B are formed wider than the head gaps 1A and 2A so that the head gaps 1A and 2A are in stable contact with the tape. The leading head 2 and the trailing head 1 are arranged with a predetermined gap distance GL in the rotation direction, and are arranged with a step H in the linear direction orthogonal to the rotation direction arrow 3. .

The heads 1 and 2 thus constructed are fixed to the head base 6 and arranged on the upper rotary drum 7A. The leading head 2 and the trailing head 1 project from the peripheral surface of the upper rotary drum 7A by a predetermined amount, for example, a projecting amount B.
Is mounted and fixed on the head base 6. Then, the head base 6 is fastened to the rotary drum 7A with the screw 5, and rotates in the arrow 3 direction. 2 rotating drum units
Since the two head gaps 1A and 2A are arranged so as to be displaced, the head gaps 1A and 2A can simultaneously record or reproduce on the tape.

Next, with reference to FIGS. 4, 5, and 6, a method in which the double azimuth heads 1 and 2 simultaneously record and reproduce will be described. FIG. 4 is a perspective view showing the vicinity of the rotary drum device of the magnetic recording / reproducing apparatus. The magnetic tape 13 is wound around the rotary drum device 7 and is fed in the tape running direction indicated by the arrow R for recording and reproduction. The rotary drum device 7 is composed of an upper rotary drum 7A and a lower fixed drum 7B, and a pair of heads 1 and 2 having different azimuth angles are provided adjacent to and projecting from the lower part of the upper rotary drum 7A.

The upper rotary drum 7A rotates counterclockwise in the direction of the arrow. Therefore, the heads 1 and 2 come in contact with the tape 13 first, and the trailing head 1 comes in contact later.
Becomes Since the trailing head 1 is arranged with a predetermined step H with respect to the leading head 2, the leading head 2 and the trailing head 1 simultaneously record or reproduce two tracks on the tape 13. It can be performed. The tape guides 9 and 12 arranged in the path of the tape 13 form a traveling path of the magnetic tape 13. Inclined guides 1 arranged in an inclined form on the upstream side and the downstream side of the rotary drum device.
Reference numerals 0 and 11 are guides for obliquely winding the magnetic tape 13 around the rotary drum 7 inclined by a predetermined angle. The tape driving means for supplying the tape to the rotary drum device, the tape winding cassette, and the like are not shown.

FIG. 5 is an enlarged view of the head window 50 provided on the upper rotary drum 7. In FIG. 5, W is the width of the head window, and t is the height of the head window. The dimensions of W and t will be described later. FIG. 6 shows a recording pattern recorded on the tape 13 by the rotary drum device. The A head and the B track are simultaneously recorded on the tape 13 obliquely by the leading head 2 and the trailing head 1. At this time, the pitch H ′ between the A track and the B track is approximately equal to the height deviation (step) H of the heads 1 and 2 provided in the direction orthogonal to the rotating direction of the drum shown in FIG.

Next, the operation of the rotary drum device of the present invention will be described. Shape of head and contact length of tape (see FIGS. 7 to 9). 7 to 9 are top views of the head for explaining the shape of the head. Since the leading head and the trailing head have the same shape, only the leading head 2 is shown. FIG. 7 shows a head shape according to the present invention. Head 2
Is the first region 20 (including the radius of curvature R
1) and a second region adjacent to and adjacent to the first region 20.
Region 25 (having a radius of curvature of R2). At this time, the radius of curvature is set so as to satisfy the relationship of the radius of curvature R1 of the first region 20> the radius of curvature R2 of the second region 25. Here, the radius of curvature means the radius of curvature in the rotation direction given along the center line of the core of the head.

The tape 13 is in contact with the head 2 from the contact Q to the head gap 2A.
Therefore, the distance between the contact Q and the gap 2A, that is, from the contact Q of the tape in the first region to the head gap 2
The length in the direction perpendicular to the center line V up to A is defined as the contact length L between the head and the tape. In the head 2 shown in FIG. 7, when the tape is wound around the head 2 from the drum 7 of the rotary head device, the contact length with which the tape contacts the head 2 (in the direction perpendicular to the center line V from the contact Q to 2A). The length) becomes the length L1.

FIGS. 8 and 9 show comparative examples in which the radius of curvature of the head is changed. The head 2x shown in FIG. 8 has a radius of curvature R that is the same as the radius of curvature of the first region of the head 2.
1. The head 2y shown in FIG. 9 shows a case where the head 2y is formed with a radius of curvature R3, which is smaller than R1. When the tape is wound around the heads 2x and 2y, the tapes are the heads 2x and 2
The contact length in contact with y is defined as Qx, Q according to the above definition.
The lengths L2 and L3 from y to the head gap 2A are set.

Head 2x having an arc with a large radius of curvature
Contact Q of head 2y having a smaller radius of curvature than contact Qx of
y is close to the head gap 2A, and the contact length is L2> L3. Also, the contact point Q in the head 2
Is set on an arc having a radius of curvature R2 shorter than the radius of curvature R1, the contact point Q is closer to the head gap 2A than the contact point Qx, and the contact length is L2> L1. On the other hand, the contact point Q of the head 2 is separated from the radius of curvature R1 having a larger radius of curvature than the head 2y to form the head gap 2A, so that the contact length is L1> L3. From the above,
The head has a long radius of curvature and the tape contact length L of the head 2x
2 is the largest and the tape contact length L3 of the head 2y having the shortest radius of curvature is the shortest. The contact length L1 of the head 2 of the present invention, which has R1 having a large radius of curvature and R2 having a small radius of curvature and in which the contact point Q is arranged on an arc having a small radius of curvature, is an intermediate length. That is, the contact length L with which the tape 13 contacts the head is L3 <L1 <L2.

Head contact length and head contact state (see FIG. 10). In the graph shown in FIG. 10, the abscissa represents the shape of the head as the contact length, and the ordinate represents the head contact state by the waveform rate, to explain the relationship between the head shape and the contact state. Here, the form factor is represented by the ratio (b / a) of the maximum value a and the minimum value b of the output in the envelope waveform. That is, when the waveform rate is large, the contact pressure is high, and as the waveform rate is small, the contact pressure is low. According to this graph, when the contact length becomes longer than a certain value, the waveform ratio decreases, the contact between the gap and the tape (contact pressure) decreases, and the wrapping of the head with the tape becomes unstable. . This is because the wrapping of the head becomes unstable on the drum input side and the drum output side where the head comes into contact with the lower end or the upper end of the tape, so the ratio of the maximum value a to the minimum value b of the output in the envelope waveform. The form factor represented by (b / a) decreases. That is, in order to secure a constant contact pressure with the head, it is necessary to make the contact length between the tape 13 and the head 2 smaller than a predetermined value.

Therefore, the radius of curvature R1 forming the first region and the radius of curvature R2 forming the second region are set so that the contact length becomes smaller than a predetermined value, for example, a value of 3 or less in the graph. By setting, stable head contact can be secured.

Degree of wear of the head (see FIG. 11). A wear resistance test was conducted using the head 2, the head 2x, and the head 2y. The graph shown in FIG. 11 is a wear curve representing experimental results, in which the horizontal axis represents the running time and the vertical axis represents the amount of head wear. According to this graph, the head 2x having a long contact length with the tape has a low degree of wear and has a large margin in terms of reliability of head life. On the other hand, the head 2y, which has a short contact length with the tape, wears quickly and has low reliability regarding the head life. Further, the head 2 in which most of the tape running portions have the same radius of curvature as the head 2x, has a wear amount close to that of the head 2x and has a high head life reliability. Due to the above facts, the head has two circular arcs (an arc with a large radius of curvature and an arc with a small radius of curvature).
The head 2 thus formed exhibits a small amount of wear similar to a head having a large radius of curvature like the head 2x, and has good head contact performance similar to a head having a small radius of curvature like the head 2y. .

As described above, in the rotary head device and the head of the recording / reproducing device, the radius of curvature in the rotating (sliding) direction of the head forms the first region including the gap and the radius of curvature R.
1 and a radius of curvature R2 forming a second region adjacent to the first region, the radius of curvature R of the first region is reduced in order to reduce the change over time in the gap portion.
1 is set to a predetermined value. Further, in order to increase the contact pressure of the gap portion, the radius of curvature R2 of the region continuous with the first region is set small, and the connecting portion P of the two arcs is formed.
Is set so as to be positioned in the direction of the head adjacent to the contact point connected from the outer circumference of the rotary drum to the circle formed by R1, that is, the connection portion where the tape first contacts the head. By setting in this way, the contact area can be reduced while maintaining the radius of curvature of the tape contact area of the head, and a good head touch performance can be obtained, and a double azimuth head with a small change over time can be obtained. Is.

Next, another embodiment will be described. This recording / reproducing device has a drum diameter of 40 mm and a head protrusion amount of 26 μ.
An example of actual measurement of head contacts when the present invention is applied to a rotary drum device of m is shown. Here, the radius of curvature R1 and the radius of curvature R2 are R1 = 7 mm to 9 mm and R2 =
It was set to 5.5 mm. As the tape, a standard thick tape having a thickness of 11 μm and a 13 μm thick tape having higher rigidity were used. In addition, the size of the head window provided on the upper drum is
As shown in FIG. 5, the shape is rectangular and the width W is about 3.5 m.
m and height t are about 1.2 mm. The tape tension at the time of recording or reproducing a signal on the tape at this time is set to 10 to 15 gf at the entrance of the rotary head device.

(1) The relationship between the contact length and the corrugation rate for a standard tape having a thickness of 11 μm will be described with reference to FIG. The horizontal axis is the contact length, and the vertical axis is the waveform rate. The waveform rate of 0.8 or more is set as the actual use range. According to this graph, 0.85 or more can be stably ensured in the range where the contact length L is smaller than 400 μm. Also, the contact length L is 400 μm
In the above case, the tape contact surface pressure in the gap portion becomes low, so that the tape tension and the head mounting posture are easily affected, and the waveform ratio is deteriorated. From this fact, it can be seen that a reliable head contact can be obtained by setting the contact length L between the tape and the head to be less than 400 μm. However, as the contact length decreases, the contact surface pressure between the head and the tape increases, resulting in severe head wear. Therefore, from the viewpoint of head wear, the contact length between the tape and the head is set to 150 μm or more. From these matters, the contact length L is 150
Wear resistance by setting the range of μm ≦ L ≦ 400 μm,
Improvements from both sides of the head contact are achieved. Also, in order to ensure reliability from the viewpoint of head friction, 2
00 μm ≦ L ≦ 400 μm is preferable, and in order to further improve durability, 300 μm ≦ L ≦ 40
More preferably, it is 0 μm.

(2) With reference to FIGS. 13 to 18, the relationship between the waveform ratio and the shape of the head when a highly rigid 13 μm thick tape is used will be described. The length of the contact area in the direction perpendicular to the center line V (dotted line in the figure) between the adjacent heads of the double azimuth head, that is, the horizontal distance from the contact Q to the head gap 2A is M. To do. When the amount of change in height between the contact Q and the head gap position in the contact area is N, the rate of change in height in the contact area of the head can be expressed by a = N / M. The rate of change in height a increases as the radius of curvature R1 of the contact area decreases. Alternatively, even if the radius of curvature R1 is the same,
The center becomes larger as it is located closer to the adjacent head.

Referring to FIG. 18, first, the relationship between the rate of change a in the contact area and the corrugation rate when using a tape having a thickness of 11 μm is shown. Here, in the graph shown in FIG. 18, the horizontal axis represents the rate of change in the contact area and the vertical axis represents the waveform ratio. From this graph, it is understood that the tape having a thickness of 11 μm can stably secure the corrugation rate of 0.8 or more in a wide range of the change ratio of the contact area of 0.015 to 0.06. Next, the case of a 13 μm thick tape having higher rigidity will be described. The relationship between the rate of change in the height of the contact area and the form factor is examined (see FIG. 14). From this graph, when the ratio a of the height change of the contact area is 0.036 or less, the waveform ratio is 0.8 or more, which is the actual use range, but the change of the height of the contact area It can be seen that the waveform ratio (head contact) deteriorates when the ratio a is 0.036 or more.

From the above results, in the case of a system using only 11 μm thick tape, the contact length is 400 μm or less, and the height change of the contact area is 0.015 ≦ a ≦ 0.
By setting the radius of curvature of the head so as to be 06, a waveform ratio of 0.8 or more can be secured. Also 0.020 ≦
By setting a ≦ 0.055, a waveform ratio of 0.85 or more can be secured. On the other hand, when using two or more kinds of tapes of 11 μm and 13 μm, the contact length should be 400 μm or less,
And the height change of the contact area is 0.015 ≦ a ≦ 0.036
By setting the radius of curvature of the head so that, the waveform ratio of 0.8 or more can be secured. In addition, 0.020 ≦ a ≦
By setting it to 0.036, it is possible to secure a waveform ratio of 0.85 or more. Next, the cause of deterioration of the head contact of the 13 μm thick tape will be described. FIG. 15 is a schematic diagram showing the state of the tape and the head on the drum entry side. The high-rigidity 13 μm-thick tape 130 is produced by
When incident on 0, it deforms along the shape of the contact portion of the head. However, since the rigidity is high, the amount of deformation in the direction of the head protrusion shown by the arrow 133 is large. As a result, when the trailing head 1 is incident, spacing 135 is generated between the gap portion 2A and the tape, causing head contact deterioration. That is, when the head height ratio is large, contact deterioration of the trailing head 1 occurs on the drum entrance side.

FIG. 16 shows the shape of the envelope waveform in this state. The horizontal axis represents time and the vertical axis represents output voltage. The envelope waveform shows a state in which it takes time D until the maximum output reaches E when the head is incident on the tape, and has a shape that is greatly deteriorated on the incident side. According to the above examples, even when tapes having different rigidity are used, the contact length is 400 μm or less, and the height change ratio in the contact region is 0.036 or less.
The head contact has a waveform ratio of 0.85, which is the actual range of use.
It can be seen that the above can be secured. As described above, by setting the radii R1 and R2 so that the contact length L is L ≦ 400 μm, good head contact can be achieved. Further, by setting the rate of change in height a in the contact area in contact with the tape to be a ≦ 0.036, deterioration of the waveform ratio can be almost eliminated even when a thicker tape having higher rigidity runs. Is.

In this embodiment, the size of the head window provided on the upper drum is W3.5 mm in width and t1.2 in height.
However, it is not limited to this, and the size and shape do not cause scratches due to the tape getting into the window due to the window being too large and difficulty in assembling due to the small window. If For example, in the case of a rectangular shape, the width W is 3 mm to 4 mm and the height t is 1 mm to 2 mm.
The same effect can be obtained by setting the range to. Further, the head protrusion amount B is set to 26 μm, but the same effect can be obtained with 20 μm to 29 μm. In addition, there is a means to generate a regulating force on the tape by providing an inclination at the lower end of the upper drum, but regarding such an upper drum, the tangent line from the arc forming the outermost periphery supporting the tape to the head Needless to say, it can be considered in the same way by tying.

Further, although the above-described embodiment is a rotary head device having a structure in which an upper drum having a head mounted thereon rotates, it can be applied to an upper fixed drum having a structure in which the head is mounted on a middle rotating drum. . The rotary drum device shown in FIG. 17 includes an upper fixed drum 31, a lower fixed drum 32,
It is composed of a coupler 33 that fastens the upper and lower drums, and the heads 1 and 2 are mounted on a medium rotating drum (not shown) for recording and reproduction. In this apparatus, the same consideration can be made with reference to the outer peripheral surface of the upper fixed drum 31.

Next, a method of manufacturing the head of the present invention and a method of measuring the radius of curvature of the tip shape of the head will be described.
FIG. 19 schematically shows a method of manufacturing a head chip. First, a block 1004, which is a mass of many heads, is formed with a radius of curvature R2. Next, the unnecessary portion 1002 is deleted and the chip-shaped block 1000 is formed. The thickness of the core is cut out from the chip-shaped block 1000, and the head chip 2 is completed. The head chip 2 is wound with a head (not shown), and is attached to the head base 6 together with a pair of heads. The heads 1 and 2 attached to the head base 6 are cylindrical members 10
20 is attached by protruding a predetermined amount from the outer periphery of the cylinder,
The tip of the head is shaved with the wrapping tape 1022 to form R1. 20 shows a state in which one curvature half radius R2 is formed, and FIG. 21 shows a state in which R1 is formed by grinding 1006 by cylindrical grinding with a lapping tape. FIG.
23 is a perspective view of the head before cylindrical grinding, and FIG. 23 is a perspective view of the head after cylindrical grinding. In FIG. 22, the head has a radius of curvature R2 only in the tape sliding direction. On the other hand, the head after cylindrical grinding has curvatures of R1 and R2 in the sliding direction, and also has a radius of curvature RE in the direction perpendicular to the sliding direction. Therefore, the contact end portion between the tape and the head has a curved shape as indicated by the dotted line in FIG. Therefore, M and N are contact points Q at the intersections of the center line C of the thickness of the head core (shown by the one-dot chain line in FIG. 23) and the dotted line of the contact end portion in the figure, and the center line C It is to measure along.

Next, a method for measuring the radius of curvature of the tip of the head will be described with reference to FIGS. 24 and 25. The method described in this embodiment is a case where a non-contact type interference lens is used. In FIG. 24, reference numeral 2000 is a housing of a non-contact type interference lens of a microscope, and 2010 is a lens. When the head surface is observed using this lens, a 0th-order interference fringe appears at the focal point of the lens I as shown in FIG. 25, and the height is used as a reference for every change in the height of 1/2 of the wavelength of the light source. The following interference fringes e are generated. The tip shape can be measured by measuring the size of the interference fringes e. When measuring R1 and R2,
The head may be arranged so as to be perpendicular to the lens. The tip shape of the head can be measured by the above method.

[0038]

As described above, according to the present invention,
In a rotary head device having adjacent double azimuth heads and a rotary head type recording / reproducing device, the sliding part of the gap part is adjusted by optimizing the shape of the head in the sliding direction with two radii of curvature. The area of can be optimized and a good head contact can be secured. Further, since the radius of the gap portion can be kept large, deterioration of the head tip over time due to long-time running is small, and stable performance can be secured.

Further, since the head of the present invention has a shape in the rotating direction formed by arcs having two different radii of curvature, the head gap portion is brought into contact with the tape by optimizing these radii of curvature. Good pressure can be secured by optimizing the pressure.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration of a tape sliding portion of a double azimuth head of the present invention.

FIG. 2 is a front view of a head showing the structure of a double azimuth head of the present invention.

FIG. 3 is a schematic diagram showing a state in which a head used in the present invention is attached to an upper rotary drum.

FIG. 4 is a diagram illustrating an outline of a rotary drum of the present invention and its surroundings.

FIG. 5 is a diagram illustrating an outline of a head window of a rotary drum of the present invention.

FIG. 6 is a schematic diagram showing tracks recorded on a tape.

FIG. 7 is a schematic diagram showing the tip shape of the head.

FIG. 8 is a schematic view showing the tip shape of the head.

FIG. 9 is a schematic view showing the tip shape of the head.

FIG. 10 is a graph showing the relationship between contact length and waveform rate.

FIG. 11 is a graph showing the relationship between time and head wear amount.

FIG. 12 is a graph showing the relationship between contact length and waveform rate.

FIG. 13 is a schematic diagram illustrating head shape parameters.

FIG. 14 is a graph showing the relationship between the rate of change in height of the contact area of the head and the waveform rate.

FIG. 15 is a schematic diagram for explaining the cause of deterioration of the corrugation rate of a thick tape.

FIG. 16 is a diagram showing the shape of a deteriorated envelope waveform.

FIG. 17 is a drum structure diagram illustrating an example applied to an upper fixed drum.

FIG. 18 is a graph showing the relationship between the rate of change in height of the contact area of the head and the waveform rate.

FIG. 19 is a schematic view showing a method of manufacturing a head.

FIG. 20 is a schematic diagram showing a state before cylindrical grinding of the head.

FIG. 21 is a schematic view showing a state after cylindrical grinding of the head.

FIG. 22 is a perspective view showing a state before cylindrical grinding of the head.

FIG. 23 is a perspective view showing a state after cylindrical grinding of the head.

FIG. 24 is a schematic view showing a method of measuring the radius of curvature of the head.

FIG. 25 is a schematic diagram of interference fringes of the head when measuring the radius of curvature of the head.

[Explanation of symbols]

 1 Trailing head 2 Leading head 2A Head gap 6 Head base 7 Rotating drum 7A Upper rotating drum 7B Lower fixed drum 13,130 Tape P Connecting part Q contact

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinya Fujimori 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Hitachi, Ltd. Multimedia system development headquarters (72) Hidekazu Takeda Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa 292 Hitachi Ltd., Multimedia Systems Development Headquarters (72) Inventor Atsushi Inoue Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa Prefecture 292 Hitachi Systems Ltd. Multimedia Systems Development Headquarters (72) Inventor Yoshiharu Yamashita Ibaraki Prefecture 1410 Inada, Hitachinaka City, Hitachi Ltd., Personal Media Equipment Division (72) Inventor, Kuniaki Hirayama, Ibaraki Prefecture 1410 Inada City, Hitachi, Ltd. Personal Media Equipment Division, Hitachi, Ltd. (72) Inventor, Yoshio Uemura Hitachinaka, Ibaraki Prefecture 1410 Inada, Hitachi, Ltd., Personal Media Equipment Division, Hitachi, Ltd. (72) Inventor, Masahiko Fujishiro, Hitachinaka, Ibaraki Prefecture, Inada, Hitachi, Ltd. Personal Media Equipment Division, Hitachi, Ltd. (72) Toshihiko Imachi, Hitachida, Hitachi, Japan 1410 Stock company Hitachi, Ltd. Personal Media Equipment Division

Claims (41)

[Claims] 1. A head having a head gap and a head core, a rotary drum to which the head is attached, and a fixed drum rotatably supporting the rotary drum, wherein the head is a first head. And a second head. The first head and the second head are arranged side by side with different azimuth angles with a predetermined gap distance in the rotation direction of the rotary drum. In the rotary head device arranged with a predetermined step in a direction orthogonal to the rotation direction of the rotary drum, the first head and the second head have a first region having a head gap and a connecting portion. A second region adjacent to the first region via a first region, and the first region has a radius of curvature in the rotational direction given along the center line of the core of the head in the dimension R1.
The second region is formed by an arc having a radius R2 of curvature in the rotational direction given along the center line of the core of the head as a radius R2, and has a relationship of radius of curvature R1> radius of curvature R2. A rotary head device. 2. The head comprises a first head and a second head from a contact end of the tape in the first region to a head gap.
When the length of the head in the direction perpendicular to the centerline of the head is the contact length L between the tape and the head, the radius of curvature R1 of the first region and the radius of curvature of the second region are set so that L ≦ 400 μm. The rotary head device according to claim 1, wherein R2 is set. 3. The head includes a first head and a second head from a contact end of the tape in the first region to the head gap.
When the length in the direction perpendicular to the center line of the head is the contact length L between the tape and the head, the contact length L is 150 μm ≦ L ≦ 400 μm, and the radius of curvature R1 of the first region is 2. The rotary head device according to claim 1, wherein a radius of curvature R2 of the second area is set. 4. The head comprises a first head and a second head from a contact end of the tape in the first region to the head gap.
When the length of the tape in the direction perpendicular to the center line of the head is the contact length L between the tape and the head, the contact length L is 200 μm ≦ L ≦ 400 μm and the radius of curvature R1 of the first region 2. The rotary head device according to claim 1, wherein the radius of curvature R2 of the region 2 is set. 5. The head comprises a first head and a second head from a contact end of the tape in the first region to a head gap.
When the length of the tape in the direction perpendicular to the center line of the head is the contact length L between the tape and the head, the contact length L and the radius of curvature R1 of the first region are set to 300 μm ≦ L ≦ 400 μm. 2. The rotary head device according to claim 1, wherein the radius of curvature R2 of the region 2 is set. 6. The height change a of the contact area of the head is such that a ≦ 0.036 when the contact area between the first area of the head and the head gap is the area of contact with the tape. The rotary head device according to any one of claims 1 to 5, wherein a radius of curvature R1 of the first area and a radius of curvature R2 of the second area are set in the above. Here, a = N / M N: displacement of the head in the center line direction between adjacent heads in the contact region. M: Displacement of the head in the direction orthogonal to the center line between adjacent heads in the contact area. 7. The height change a of the contact area of the head is 0.015 ≦ a ≦ 0. The rotary head device according to any one of claims 1 to 5, wherein the radius of curvature R1 of the first region and the radius of curvature R2 of the second region are set to be 06. Here, a = N / M N: displacement of the head in the center line direction between adjacent heads in the contact region. M: Displacement of the head in the direction orthogonal to the center line between adjacent heads in the contact area. 8. The height change a of the contact area of the head is 0.020 ≦ a ≦ 0. When the contact area with the tape is from the contact end of the first area with the tape to the head gap. 6. The rotary head device according to claim 1, wherein the radius of curvature R1 of the first area and the radius of curvature R2 of the second area are set so as to be 055. Here, a = N / M N: displacement of the head in the center line direction between adjacent heads in the contact region. M: Displacement of the head in the direction orthogonal to the center line between adjacent heads in the contact area. 9. The height change a of the contact area of the head is 0.015 ≦ a ≦ 0 when the contact area between the head and the head gap from the contact area with the tape in the first area is 0.015 ≦ a ≦ 0. 6. The rotary head device according to claim 1, wherein the radius of curvature R1 of the first area and the radius of curvature R2 of the second area are set so as to be 036. Here, a = N / M N: displacement of the head in the center line direction between adjacent heads in the contact region. M: Displacement of the head in the direction orthogonal to the center line between adjacent heads in the contact area. 10. The height change a of the contact area of the head is 0.020 ≦ a ≦ 0. When the contact area with the tape is from the contact end of the head to the tape in the first area to the head gap. 6. The rotary head device according to claim 1, wherein the radius of curvature R1 of the first area and the radius of curvature R2 of the second area are set so as to be 036. Here, a = N / M N: displacement of the head in the center line direction between adjacent heads in the contact region. M: Displacement of the head in the direction orthogonal to the center line between adjacent heads in the contact area. 11. The head according to claim 1, wherein the radius of curvature R1 of the first region is set to 6 mm ≦ R1 ≦ 10 mm, and the radius of curvature R2 of the second region is set to 4 mm ≦ R2 ≦ 6 mm. The rotary head device according to any one of claims 1 to 10. 12. The head has a radius of curvature R1 in a first area set to 6 mm ≦ R1 ≦ 9 mm and a radius of curvature R2 in a second area set to 5.4 mm ≦ R2 ≦ 5.6 mm. The rotary head device according to any one of claims 1 to 10. 13. The head according to claim 1, wherein the radius of curvature R1 of the first region is set to 7 mm ≦ R1 ≦ 9 mm, and the radius of curvature R2 of the second region is set to approximately 5.5 mm. 10. The rotary head device according to any one of 10. 14. The rotary head device has a rectangular head window in which the head projects from an outer peripheral portion of the rotary head device, and a long side W of the head window is 3.0 mm ≦ W ≦.
14. The rotary head device according to claim 1, wherein the length t is set to 4.0 mm and the short side t is set to 1.0 mm ≦ t ≦ 1.5 mm. 15. The rotary head device according to claim 1, wherein the head is attached so as to project from the outer peripheral surface of the rotary head device by 20 μm to 29 μm. 16. The rotary head device according to claim 1, wherein the head is attached so as to protrude from the outer peripheral surface of the rotary head device by approximately 26 μm. 17. A tape is wound around a rotary head device over a predetermined angle, and information is recorded on the tape, or a tape is recorded.
In the recording / reproducing apparatus for reproducing a signal from a head, the rotary head device includes a head having a head gap and a head core, a rotary drum to which the head is attached, and a fixed drum that rotatably supports the rotary drum. The head of the rotary head device is composed of a pair of heads composed of a first head and a second head, and the first head and the second head are, in the rotation direction of the rotary drum,
The first head and the second head are provided side by side with a predetermined gap distance and have a predetermined step in a direction orthogonal to the rotation direction of the rotary drum, and the first head and the second head have a head gap. An area and a second area adjacent to the first area via a connecting portion, and the first area has a radius of curvature R1 given along the center line of the core of the head in the direction of rotation, The area 2 is formed by an arc having a radius R2 of curvature in the direction of rotation given along the center line of the core of the head, and the rotary head device is configured to have a relationship of radius of curvature R1> radius of curvature R2. A recording / playback device provided. 18. The tape and the head have a length in a direction perpendicular to a center line of the first head and the second head from a contact end of the tape in the first region to a head gap. 18. The recording according to claim 17, wherein the radius of curvature R1 of the first region and the radius of curvature R2 of the second region are set such that L ≦ 400 μm when the contact length L is L ≦ 400 μm. Playback device. 19. The tape and the head have a length in a direction perpendicular to a center line of the first head and the second head from a contact end of the tape in the first region to the head gap. 18. The radius of curvature R1 of the first region and the radius of curvature R2 of the second region are set so that when the contact length L is set to 150 μm ≦ L ≦ 400 μm. Recording and reproducing device. 20. The tape has a length in a direction perpendicular to a center line of the first head and the second head from a contact end of the tape in the first region to the head gap. 18. The recording / reproducing apparatus according to claim 17, wherein the radius of curvature R1 of the first region and the radius of curvature R2 of the second region are set so that when the contact length L is set to 200 μm ≦ L ≦ 400 μm. . 21. The head has a length in a direction perpendicular to a center line of the first head and the second head from a contact end of the tape in the first region to the head gap. 18. The recording / reproducing apparatus according to claim 17, wherein the radius of curvature R1 of the first region and the radius of curvature R2 of the second region are set so that when the contact length L is 300 μm ≦ L ≦ 400 μm. . 22. When the head has a contact area with the tape from a contact end of the first area with the tape to the head gap, a height change a of the contact area is a ≦ 0.036. 22. The recording / reproducing apparatus according to claim 17, wherein a radius of curvature R1 of the first area and a radius of curvature R2 of the second area are set to. Here, a = N / M N: displacement of the head in the center line direction between adjacent heads in the contact region. M: Displacement of the head in the direction orthogonal to the center line between adjacent heads in the contact area. 23. When the head has a contact area from the contact end with the tape in the first area to the head gap as a contact area with the tape, the height change a of the contact area is 0.015 ≦ a ≦ 0. 22. The recording / reproducing apparatus according to claim 17, wherein the radius of curvature R1 of the first area and the radius of curvature R2 of the second area are set to be 06. Here, a = N / M N: displacement of the head in the center line direction between adjacent heads in the contact region. M: Displacement of the head in the direction orthogonal to the center line between adjacent heads in the contact area. 24. When the head has a contact area with the tape from a contact end of the first area with the tape to the head gap, a height change a of the contact area is 0.020 ≦ a ≦ 0. 22. The recording / reproducing apparatus according to claim 17, wherein the radius of curvature R1 of the first area and the radius of curvature R2 of the second area are set so as to be 055. Here, a = N / M N: displacement of the head in the center line direction between adjacent heads in the contact region. M: Displacement of the head in the direction orthogonal to the center line between adjacent heads in the contact area. 25. When the head has a contact area with the tape from a contact end of the first area with the tape to the head gap, a height change a of the contact area is 0.015 ≦ a ≦ 0. 22. The recording / reproducing apparatus according to claim 17, wherein the radius of curvature R1 of the first area and the radius of curvature R2 of the second area are set so as to be 036. Here, a = N / M N: displacement of the head in the center line direction between adjacent heads in the contact region. M: Displacement of the head in the direction orthogonal to the center line between adjacent heads in the contact area. 26. In the head, when the contact area with the tape is from the contact end of the first area with the tape to the head gap, the height change a of the contact area is 0.020 ≦ a ≦ 0. 22. The recording / reproducing apparatus according to claim 17, wherein the radius of curvature R1 of the first area and the radius of curvature R2 of the second area are set so as to be 036. Here, a = N / M N: displacement of the head in the center line direction between adjacent heads in the contact region. M: Displacement of the head in the direction orthogonal to the center line between adjacent heads in the contact area. 27. The head has a radius of curvature R1 in the first area set to 6 mm ≦ R1 ≦ 10 mm and a radius of curvature R2 in the second area set to 4 mm ≦ R2 ≦ 6 mm. 27. The recording / reproducing apparatus according to claim 26. 28. In the head, the radius of curvature R1 of the first area is set to 6 mm ≦ R1 ≦ 9 mm, and the radius of curvature R2 of the second area is set to 5.4 mm ≦ R2 ≦ 5.6 mm. The recording / reproducing apparatus according to any one of claims 17 to 26. 29. The head according to claim 17, wherein the radius of curvature R1 of the first region is set to 7 mm ≦ R1 ≦ 9 mm, and the radius of curvature R2 of the second region is set to about 5.5 mm. The recording / reproducing apparatus according to any one of 26. 30. The rotary head device has a rectangular head window in which the head projects from an outer peripheral portion of the rotary head device, and a long side W of the head window is 3.0 mm ≦ W ≦.
27. The recording / reproducing apparatus according to claim 17, wherein the length t is set to 4.0 mm and the short side t is set to 1.0 mm ≦ t ≦ 1.5 mm. 31. The recording / reproducing according to claim 17, wherein the head of the rotary head device is attached so as to project from the outer peripheral surface of the rotary head device by 20 μm to 29 μm. apparatus. 32. The head of the rotary head device is mounted so as to protrude from the outer peripheral surface of the rotary head device by approximately 26 μm.
The recording / reproducing apparatus according to any one of 0. 33. The recording / reproducing apparatus according to claim 17, wherein the rotary head device rotates at least at a rotational speed of approximately 1800 rpm when recording or reproducing on a wound tape. . 34. The tape used for the recording or reproducing is a tape having two or more kinds of thicknesses of at least about 11 μm and about 13 μm.
34. The recording / reproducing apparatus according to claim 33. 35. The tape wound around the rotary head device forms a predetermined tape running path, and the tension T in the longitudinal direction of the tape at the entrance side of the rotary head device when recording or reproducing is 10 gf. The recording / reproducing apparatus according to any one of claims 17 to 34, wherein ≤T≤15gf is set. 36. A head mounted on one head base is composed of a pair of heads including a first head and a second head, and the first head and the second head have a predetermined gap distance. In the head that is provided side by side, the first head and the second head each include a first region having a head gap, and a second region that is adjacent to the first region via a connecting portion, The first region has a radius of curvature R1 in the sliding direction given along the center line of the head core.
The second region is formed by an arc having a radius of curvature R2 in the sliding direction given along the center line of the core of the head, and has a relationship of radius of curvature R1> radius of curvature R2. Head of rotating head device. 37. The head according to claim 36, wherein the radius of curvature R1 of the first region is set to 6 mm ≦ R1 ≦ 10 mm, and the radius of curvature R2 of the second region is set to 4 mm ≦ R2 ≦ 6 mm. A head of the described rotary head device. 38. In the head, the radius of curvature R1 of the first region is set to 6 mm ≦ R1 ≦ 9 mm, and the radius of curvature R2 of the second region is set to 5.4 mm ≦ R2 ≦ 5.6 mm. The head of the rotary head device according to claim 36. 39. The head of the head device has a range of a radius of curvature R1 of the first region of 7 mm ≦ R1 ≦ 9 mm,
The head of the rotary head device according to claim 36, wherein the radius of curvature R2 of the area is set to about 5.5 mm. 40. A head disposed in the rotary head device has a length L from the contact portion of the tape in the first region to the head gap and a radius of curvature R1 of the first region and a first region so that L ≦ 400 μm. The head according to claim 36, wherein the radius of curvature R2 of the region 2 is set. 41. When the head disposed in the rotary head device has a tape contact area of the head from the tape contact portion in the first area to the head gap, the height change a of the contact area is a ≦ 0. 37. The head according to claim 36, wherein the radii R1 and R2 are set so as to be 036. Here, a = N / M N: displacement of the head in the center line direction between adjacent heads in the contact region. M: Displacement of the head in the direction orthogonal to the center line between adjacent heads in the contact area.