JPH0517604B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic recording and reproducing apparatus using a helical scan, such as a rotating head type PCM tape recorder or a segment type video tape recorder.

BACKGROUND TECHNOLOGY AND PROBLEMS Conventional magnetic recording and reproducing devices using helical scanning, such as video tape recorders (VTRs), are configured to load magnetic tape onto a rotating head drum in a helical manner. In order to eliminate this difference between the magnetic tape and the tape reel (hub), the distance of the tape path system up to the loading mechanism is lengthened and each tape guide of the loading mechanism is tilted. Since the structure was configured to correct the level difference, it took time to set the loading of the magnetic tape onto the rotating head drum, making it difficult to respond quickly during recording and playback, and the loading mechanism was complicated and relatively large, resulting in high costs. As the height increases, tension in the torsional direction acts on the magnetic tape, which has an adverse effect on the magnetic tape itself and shortens its service life.

Purpose of the Invention In view of the above-mentioned points, the present invention provides a rotating head type magnetic recording and reproducing device which simplifies the loading mechanism, shortens the tape loading distance, and improves the linearity of the helical scan recording pattern. This is what we provide.

Summary of the Invention The present invention comprises upper and lower oval cylindrical tape guide drums that are disposed opposite each other with an inclined gap of a predetermined angle, a rotary body is disposed in this gap so as to rotate along the inclination of the gap, and a rotating body is attached to the rotating body. One or more magnetic heads are fixed to one end of an electro-mechanical transducer, and the transducer is supported movably in the normal direction by a spring member so that the tips of the magnetic heads protrude from the circumferential surface of the tape guide drum. A rotary head type magnetic recording and reproducing device, characterized in that the amount of protrusion of the magnetic head can be adjusted and the movement of the magnetic head can be adjusted in the width direction of the tape to obtain linearity of a helical scan recording pattern. This makes it possible to improve the accuracy of the recorded pattern and the linearity of the recorded pattern, and to simplify the loading mechanism and shorten the loading set time.

Embodiment An example of a rotary head device applied to a rotary head type magnetic recording/reproducing apparatus of the present invention will be described below with reference to the drawings.

In the figure, 1 and 2 are upper and lower tape guide drums formed in the shape of an elliptical cylinder, and these upper and lower tape guide drums 1 and 2 face each other on the coaxial line a, and the opposing end surfaces 1a and 2a are perpendicular to the coaxial line a. It has the required inclination angle θ ₁ with respect to line b, i.e., the end faces 1a, 2a
is a perfect circle, and the peripheral surfaces of drums 1 and 2 are end surfaces 1a and 2.
The lower tape guide drum 2 is formed into an elliptical shape in which a is inclined and projected in the vertical direction.
A tape guide flange 2a is formed on the upper peripheral surface of the tape guide flange 2a in a direction perpendicular to the axis a. The upper and lower tape guide drums 1 and 2 are aligned in the axial direction with the end surface 1
a, 2a are connected by a connecting body 4 so as to provide a gap 3 of a required width. In this case, in order to prevent the upper and lower tape guide drums 1 and 2 from being misaligned, the dowel pins 5 are driven into the respective drums 1 and 2 through the connecting body 4.

A rotating body 6 is interposed in the gap 3 between the tape guide drums 1 and 2 so as to be rotated along the inclination of the end surfaces 1a and 2a, and this rotating body 6 is attached to the lower tape guide drum 2 in the direction of the drum axis a. The rotary body 6 is rotated together with a rotary shaft 7 that is tilted and pivotally supported.
are formed, and magnetic heads 9, 9' are fixed to the tips of these notches 8, 8' to form electro-mechanical transducer elements, in this example bimorph plates 10, 10' formed by stacking two piezoelectric elements. The spring member 11,1
1' so as to be movable in the normal direction.

That is, the rear parts of the bimorph plates 10, 10' are connected to parallel spring pieces 11b, 11c, 11 integrally extending from the bases 11a, 11a' of the spring members 11, 11'.
b', 11c' to support the spring member 1 in the orthogonal direction.
1 and 11' have base portions 11a and 11a' fixed to the rotating body 6 at the sides of the notches 8 and 8' by screws 12 and 12'.

The upper end of the rotating shaft 7 of the rotating body 6 extends in the direction of the upper tape guide drum 1 and is located within the drum inner space 1b, and a slip ring 13 is attached to the upper end of the rotating shaft 7. The voltage applied to the plates 10, 10' is taken in from the outside. Furthermore, the bimorph plate 10,
The double-sided electrodes 10a, 10a' of 10' are attached only to the front half.

The lower end of the rotating shaft 7 is supported by a bearing 14 built into the lower tape guide drum 2. This bearing 14 is pressed from above and below by bearing nuts 15a and 15b, and the lower tape guide drum 2 is attached to. Further, the rotary shaft 7 is provided with a rotary transformer 16 located above the bearing 14, the fixed side coil 16a is fixed to the lower tape guide drum 2, and the rotor side coil 16b is fixed to the lower tape guide drum 2.
is attached to the rotating shaft 7 and the magnetic heads 9, 9'
The rotary transformer 16 converts the input/output of recording/reproducing signals to the magnetic heads 9, 9'.

Further, the lower end of the rotating shaft 7 protrudes from the lower surface of the lower tape guide drum 2, and a pulley 17 is fixed thereto, and this pulley 17 and a drive motor (not shown)
The rotating body 6 is indirectly driven by winding a belt 18 between the two. Note that the rotating shaft 7 may be directly driven using a BSL motor. Further, a PG head 19 is fixed to the lower tape guide drum 2, and a magnet 20 is attached to the rotating body 6 in correspondence with this to detect the rotational phase of the rotating body 6.

Reference numerals 21 and 22 denote tape guide posts for winding the magnetic tape T around the upper and lower tape guide drums 1 and 2 at a required winding angle θ ₀ . The magnetic tape T is parallel to the center coaxial line a and arranged symmetrically across the long diameter part of the upper and lower tape guide drums 1, and the magnetic tape T is wrapped around the upper and lower tape guide drums 1 and 2 by the tape guide posts 21 and 22 at a wrapping angle θ. ₀ is defined, the width is regulated by flanges 21a and 22a formed at the upper ends of tape guide posts 21 and 22, and flange 2b of lower tape guide drum 2, and the tape runs smoothly in a direction perpendicular to the center coaxial line a.

Note that the upper and lower tape guide drums 1 and 2 may not have an elliptical shape over the entire circumference, but may have a shape with a relief on the circumferential surface other than the magnetic tape winding part (range of the winding angle θ ₀ ), or The flange 2b of the lower tape guide drum 2 may be formed only at the magnetic tape winding portion (in the range of the winding angle θ ₀ ).

Next, the operation of the apparatus of this example configured as described above will be explained.

The magnetic tape T has a winding angle θ ₀ around the elliptical tape guide drums 1 and 2 by the guide posts 21 and 22 on the long diameter side circumferential surface thereof, and also by the flange 2b of the lower tape guide drum 2 and the guide post 2.
The rotating body 6 is wound and slid in a direction perpendicular to the axis a while its movement in the width direction is restricted by the flanges 21a and 22a of 1 and 22, while the rotating body 6 has an inclination angle θ ₁ due to the rotating shaft 7. The magnetic heads 9 and 9' mounted on the rotary body 6 trace the magnetic tape T within the range of a winding angle θ ₀ .
A helical scan recording pattern is formed on the magnetic tape T.

In this case, the magnetic heads 9, 9' are connected to the bimorph plate 1.
0 and 10', the bimorph plates 10 and 10' can freely expand and contract by supplying an applied voltage to the double-sided electrodes 10a and 10a' of the bimorph plates 10 and 10' via the slip ring 13. The end side, that is, the front side where the magnetic heads 9 and 9' are attached, is in the vertical direction in FIG. 3, that is,
The magnetic heads 9, 9' swing in the axial direction of the rotating body 6.
will be moved in the width direction with respect to the magnetic tape T, and the bimorph plates 10, 10' will be moved in the width direction with respect to the magnetic tape T.
As shown in the figure, the parallel spring pieces 11b, 11c, 11b', 11c' of the spring members 11, 11' support the rotary body 6 in the diametrical direction through the spring members 11, 11'. Since the magnetic tape T is mounted so that it can be elastically moved in the front-rear direction in the same figure, that is, in the diametrical direction with respect to the rotating body 6, the tension of the magnetic tape T sliding on the magnetic heads 9 and 9' is reduced. As the pressing force on the magnetic heads 9, 9' changes, the magnetic heads 9, 9' are elastically moved in the diametrical direction of the rotating body 6, and the amount of protrusion of the magnetic heads 9, 9' relative to the tape guide drums 1, 2 changes. will be changed. Since the magnetic heads 9, 9' are constructed so as to be movable in the protruding direction with respect to the tape guide drums 1, 2 and in the tracking direction with respect to the magnetic tape T, a good recording pattern can be obtained.

This example device is applied to a PCM tape recorder, and as shown in Fig. 4, a magnetic tape T having a width W _T of 1.90 mm is recorded.
If you record digital audio width W _A at 0.913 mm, the upper and lower tape guide drums 1 and 2
By forming the tape into an elliptical cylinder shape with a major axis of 10 mm and a minor axis of 9.962 mm, and the tape winding angle being approximately 60 degrees, the recording pattern p is recorded in an S-curve shape as shown in Fig. 4. An ideal pattern is created by applying a voltage to the bimorph plates 10, 10' using the magnetic heads 9, 9' and performing a tracking correction of about 10-odd μm.
It can be corrected to p′. Also magnetic head 9,
9' is also moved in the normal direction by the spring members 11, 11', and the amount of protrusion is varied, so that the contact with the magnetic tape T is also optimized.

Effects of the Invention As described above, according to the present invention, the magnetic head is rotated along the circumferential surface of the elliptical cylindrical tape guide drum at a required angle of inclination, and the tape guide of the tape path system is parallel to the tape guide drum. Since the magnetic tape is run in a direction perpendicular to the tape guide drum and tape guide, the magnetic tape is always run with uniform tension without any torsional tension being applied to the tape, and the magnetic head is tracked by an electro-mechanical transducer. Since correction is performed and the amount of protrusion can be controlled by the spring member, the best recording pattern can be obtained.Furthermore, the tape path system is generally simplified because each tape guide is formed in parallel, and the loading process is also shortened. This improves the responsiveness of recording and reproducing operations. In addition, mass production is improved and costs are reduced due to the simplified structure.The present invention can be applied to, for example, a PCM tape recorder where the winding angle of the magnetic tape around the rotating head drum is small, and its effects can be achieved. It's large.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway plan view of a rotary head device applied to the present invention, FIG. 2 is a sectional view taken along line A-A in FIG. 1, FIG. 3 is an enlarged perspective view of the main parts, and FIG. FIG. 3 is an explanatory diagram of a recording pattern. 1 and 2 are the upper and lower tape guide drums, 3 is the gap,
6 is a rotating body, 7 is a rotating shaft, 9 and 9' are magnetic heads,
10 and 10' are bimorph plates as electro-mechanical conversion elements, 11 and 11' are spring members, and 11b and 1
1c, 11b', 11c' are spring pieces, 21, 22 are guide posts, and T is a magnetic tape.

Claims (1)

[Claims] 1 Upper and lower elliptical cylindrical drums are arranged oppositely with an inclined gap of a required angle, a rotating body is arranged in the gap so as to rotate along the inclination of the gap, and one or more magnetic heads are attached to the rotating body. is fixed to one end of the electro-mechanical transducer, and the transducer is supported movably in the normal direction by a spring member, so that the tip of the magnetic head is mounted so as to protrude from the circumferential surface of the drum. . A rotary head type magnetic recording and reproducing apparatus, characterized in that the amount of protrusion of the magnetic head is adjustable and the movement of the magnetic head is adjusted in the width direction of the magnetic tape to obtain linearity of a helical scan recording pattern.