JPH03283003A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To attain recording and reproduction with high S/N by providing a recording exclusive magnetic head and a reproduction exclusive magnetic head independently, setting the gap of the reproduction exclusive magnetic head smaller than that of the recording exclusive magnetic head and devising the reproduction exclusive magnetic head so as to be movable in the axial direction of a rotary drum. CONSTITUTION:The device is provided with a rotary drum 1, recording exclusive magnetic heads 2L, 2R and reproduction exclusive magnetic heads 3L, 3R fitted to the rotary drum 1 independently respectively. Then the gap of the reproduction exclusive magnetic heads 3L, 3R is set smaller than the gap of the recording exclusive magnetic heads 2L, 2R and the reproduction exclusive magnetic heads 3L, 3R are devised to be movable in the direction of the rotary shaft of the rotary drum 1. Then the magnetization power is increased by supplying a large recording current at recording and a high frequency component on a magnetic tape is sufficiently picked up at reproduction and traced onto a recording track on the magnetic tape. Thus, the recording and reproduction with high S/N are attained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to, for example, a video tape recorder (hereinafter referred to as VT).
) and digital audio tape recorders (referred to as R) and digital audio tape recorders (referred to as
The present invention relates to a magnetic recording and reproducing apparatus, such as a DAT (hereinafter referred to as DAT), which is configured to record and reproduce signals on a magnetic tape using a magnetic head.

[Prior Art] FIG. 7 is a schematic plan view of a rotating drum device in a conventional magnetic recording/reproducing apparatus, and FIG. 8 is a longitudinal sectional front view of the rotating drum device. In the figure, (1) is a rotating upper drum, which is supported on a pedestal (9) supported by a rotating shaft (14). (2L) and (2R) are magnetic heads with different azimuth angles, and a head stand (4) is removably clamped to the upper drum (1) at an interval of 1800 mm.
, (4), and the tips protrude slightly from the outer periphery of the upper drum (1).

(8) is a fixed lower drum, on which the rotating shaft (14) is freely rotatably held via a bearing (6), and a drum motor (12) is supported. There is. (13a) and (13b) are upper and lower transformers, and the upper transformer (13a) is connected to the upper drum (1
) and rotates together with the upper drum (1), and the lower transformer (13b) is fixed to the lower drum (8).

(?), (10) is′! The titS section (10) is a wiring board that electrically connects the magnetic heads (2L) and (2R) to the upper transformer (13a), respectively. The lower transformer (13b) is electrically connected to an external signal processing device (not shown). (20) is a magnetic tape.

Next, the operation of the above configuration will be explained.

While rotating the upper drum (1) at a constant high speed,
By running the magnetic tape (20) wound slightly diagonally around the outer peripheral surfaces of the upper drum (1) and lower drum (8) at a predetermined speed, the magnetic heads (2L) and (2R) are created.
contacts the magnetic tape (20) and moves diagonally across the magnetic tape (20) as shown by the arrow X in FIG.
Video and audio signals are recorded magnetically, and the recording tracks (T) are traced to reproduce the signals.

Here, a magnetic tape (20) and a magnetic head (2L).

The principles of recording and reproducing operations based on (2R) are explained in the 10th section.
A brief explanation will be provided according to FIG. A and FIG. 10B.

As shown in FIG. 10A (a), a magnetic head (2
When current flows through L) and (2R), magnetic lines of force are generated, and an S pole and a N pole are generated in the gap (g) between the magnetic heads (2L) and (2R).
A pole is formed, and many lines of magnetic force are concentrated in the gap (g), generating a strong magnetic field. When the magnetic tape (20) is brought close to such a gap (g) where the magnetic field is strong,
The fine magnetic powder in the magnetic tape (20) is magnetized in the direction of the lines of magnetic force, and its magnetization remains even if it is separated from the gear 2 tap (g).

Therefore, as shown in FIG. 10A (a), the magnetic tape (
20) While running in the direction of the t-arrow, a current with varying signal strength and frequency is fed to the magnetic field (2L).
, (2R), the magnetic tape (20) is magnetized according to the direction and strength of the current, as shown in Figure 10A (b), and the electric signal is transferred to the magnetic tape (20).
recorded in

In addition, in contrast to the above recording operation, as shown in Figure 10B (a), when the magnet (20A) with the S and N poles that emit magnetic lines of force is moved inside the coil (2OL), the coil (20L) A force acts that causes current to flow. Therefore, the 10B
As shown in Figure (b), the magnetic tape (20) on which electrical signals have already been recorded by magnetization is transferred to the magnetic
When approaching the gap part (g) of R) and traveling in the direction of the arrow, the magnetic field changes depending on the strength and frequency of magnetization.
Current flows through the coil (2b) of 2L) and (2R),
Electrical signals are picked up. Here, the gap part (
g), recording frequency (f), and tape/head speed (V)
It is necessary that the relational expression 2g≦f/V holds true.

[Problems to be Solved by the Invention] Conventional magnetic recording and reproducing devices are configured as described above, and since the recording and reproducing operations are shared by the same magnetic head, it is difficult to improve the performance of the magnetic head. It has not been possible to achieve sufficiently satisfactory performance in both reproduction, and as a result, both recording and reproduction have been forced to have compromised performance settings. Therefore, there was a problem in that the magnetization power during recording was low and the S/N ratio was greatly degraded.

Furthermore, since the magnetic head cannot be faithfully traced to the recording track during reproduction, there is a problem in that the magnetic head is affected by crosstalk between adjacent track signals and the S/N ratio during reproduction is greatly degraded.

This invention was made to solve the above-mentioned problems, and it is possible to record with high S/N by increasing the magnetization power during recording, and also to improve the tracking performance during playback and achieve high S/N. An object of the present invention is to provide a magnetic recording/reproducing device capable of performing /N reproduction.

[Means for Solving the Problems] A magnetic recording/reproducing device according to the present invention provides a recording-only magnetic head and a reading-only magnetic head independently, and sets the gap width of the reading-only magnetic head to the gap width of the recording-only magnetic head. The magnetic head is characterized in that it is set smaller than the gap width, and that the read-only magnetic head is movable in the direction of the rotation axis of the rotary drum.

[Function] According to the present invention, during recording, a large recording current is passed through the recording-only magnetic head with a wide gap width to increase the magnetization power, thereby reducing S caused by particle noise and sliding noise accompanying the magnetization of the magnetic material on the magnetic tape. /N deterioration is prevented and high S/
N recordings can be made.

In addition, during playback, a read-only magnetic head with a narrow gap sufficiently picks up the high frequency components on the magnetic tape, and the magnetic head is moved in the direction of the rotating axis of the rotating drum to precisely match the recording track of the magnetic tape. Since it can be traced, deterioration of the S/N due to crosstalk interference of adjacent track signals can be prevented, and reproduction with a high S/N can be performed.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described based on the drawings.

FIG. 1A is a schematic plan view of a rotating drum device in a magnetic recording/reproducing apparatus according to an embodiment of the present invention, and FIG. 2 is a longitudinal sectional front view of the rotating drum device. In the same figure, (1
) is a rotating upper drum supported on a pedestal (9) supported by a rotating shaft (14). f2Ll, +2R)
are recording-only fixed magnetic heads having different azimuth angles, and are mounted on the upper drum (1) at an interval of 180°.

f3L), (3R1 are movable magnetic heads for reproduction only with different azimuth angles, and 18
At an interval of 0° and at an interval of 120° with respect to the recording-only fixed magnetic head (21, 1, (2R)), a movable reproducing head unit flDO, which will be described later,
(It is attached via 1001.

(8) is a fixed lower drum, on which the rotating shaft (14) is freely rotatably held via a bearing (6), and a drum motor (12) is supported. There is. (13a) and (13b) are upper and lower transformers, and the upper transformer (13a) is the upper tram (1).
) and rotates together with the upper drum (1), and the lower transformer (+3b) is fixed to the lower drum (8).

(15) is a slip ring, which is attached to the F of the rotating shaft (14).
provided at the end. (16) is a brush that supplies current by contacting the slip ring (15).
) is a magnetic tape.

(2L) (2L), (2L), (2L)
The gap width of R) is set to 0.4 to 0.5 gm, and a movable magnetic head (3L) is used only for reproduction.

The gap width of (3R) is set to 0.3 gm.

The reason is as follows. That is, from the perspective of the recording principle shown in FIG. 10A, the relationship between the magnetization power recorded on the magnetic tape (20) and the helad gap width is as shown in the characteristic diagram of FIG. 1B, as the gap width becomes larger. Although a large recording current can flow, the deterioration of high frequency components increases. Therefore, in order to be able to exert the maximum magnetization power within a range that can tolerate the deterioration of high-frequency components during recording, a fixed magnetic head dedicated for recording (
2L) and (2R) are set to 0.
4 to 0.5 gm, and a movable magnetic head + 3L for reproduction only, in order to sufficiently pick up the high frequency components of the magnetization energy on the magnetic tape during reproduction.
+3R) gap width is set to 0.3 μm.

FIGS. 3(a) and 3(b) are a perspective sectional view and a vertical sectional front view showing the specific structure of the movable reproducing unit (1001);
1021 is a circular spring, and at one end on the circumference of one circular spring flol) there is a movable magnetic head f3L) for reproduction only.
+3R1 is fixed.

An air-core bobbin t1031 is glued to the center of the circular spring (+o+), f+oz) marked F, and a 0. 250 lφ fine copper wire
A winding coil +104) is provided.

f+051 is a permanent magnet made of rare earth cobalt, which is disposed inside the air-core bobbin +1031, and above which a pole piece f1061 made of soft iron is provided.

+1071 is a yoke provided around the air-core bobbin +103), (1091 is a cap provided on the top of the yoke f107), and Tll0) is a printed circuit board for drawing out the fill (1041) to the outside.

FIGS. 4(a) and 4(b) show the circular springs (101) and (1
02), and these circular springs (101), (
No. 102) is a beryllium copper plate with a thickness of 0.08 mm and has many slits to give it stable elasticity.

Further, a small Noryl molded product is fitted and fixed in the center of these circular springs (101) and (102), and an air-core bobbin (103) with a coil (104) is glued therein.

As shown in Figure 3, the circular spring (lol) (102) and air core pobbin (103) are glued together in this way.
It is fixed in the yoke (107) by gluing or fitting. That is, the circumferences of the circular springs (101) and (102) are fixed to the yoke (107), and the air-centered pobin (103) is fixed to the yoke (107).
) moves as a whole, the movable magnetic he, de (3L)
, (3R) only move up and down.

FIG. 5 is a partially enlarged cross-sectional view of the rotary drum device, and FIG. 6 shows the configuration of the drive section of the rotary drum device, and the operation will be explained with reference to these drawings.

As shown in Fig. 5, circular springs (101), (102)
The outer periphery of the circular spring (101) is fixed to the yoke (107), but a long piece with a notch is taken out from one end of the outer periphery of the circular spring (101), and a movable magnetic head (for reproduction only) is attached to the tip of the long piece.
3L) or (3R) is installed. A permanent magnet (1 (15)) fixed to a yoke (110) is provided in the air-core pobbin (103).

Now, as shown in the WIJS diagram, N is attached to the permanent magnet (105).
, S pole is provided, and when a current is passed through the coil (1o4) through the brush (16) and slip ring (15), Fleming's left hand rule (middle finger...current, index finger...magnetic field, thumb ... force) acts in the direction of arrow A in Fig. 5, and the air-centered pobbin (103) moves downward. At this time, the outer peripheries of the circular springs (101) and (102) are fixed to the yoke (107), but since they have soft and uniform elasticity, the bobbin (103) Move downward. Therefore, the movable magnetic heads (3L) and (3R) also move downward.

On the other hand, if the current flowing through the coil (104) is reversed, the bobbin (103) will move upward. Since the movable magnetic heads (3L) and (3R) move up and down along the rotational axis direction of the drum (1), the sliding movement between the movable magnetic heads (3L) and (3R) and the magnetic tape (20) increases. The moving surfaces are always in full contact, making it possible to pick up the maximum amount of recorded FM signals on the tape magnetic surface, and preventing damage to the tape due to edges on the outer peripheral surfaces of the movable heads (3L) and (3R).

In addition, in the drive section shown in FIG.
) from the capstan frequency oscillator (FG) signal and the control (CTL) from the control head (28)
Based on the signal, a movable magnetic head (3L) is generated by a pattern generation circuit (120) and a microcomputer (121).
, (3R) and the output is added to the addition circuit (122), (123), filter circuit (124)
), (125), gain adjustment circuit (12B), (
12? ) and current amplifiers (12B) and (128), and is applied to the coil (104) via the brush (16) and slip ring (15) to drive the movable magnetic heads (3L) and (3R). do.

That is, the position of the track with respect to the rotating plane of the movable magnetic heads (3L) and (3R) is detected from the control signal and the FG multiplied signal of the capstan (27) that effectively divides it, and the movable magnetic head (3R) for reproduction only is detected. 3L), (
3R) is accurately tracing the recorded track (τ) from the point where the reproduced FM envelope detection signal is maximum, and the movable magnetic head (3L),
(3R) is driven in the vertical direction. In addition, (3
1) is a control signal recorded on the magnetic tape (20).

As described above, it is possible to accurately trace one recorded track (T) on the magnetic tape (20) as shown in FIG.
Due to the narrow gap width of L) and (3R) themselves, high S/N reproduction can be performed without being affected by crosstalk signals from adjacent tracks. can sufficiently pick up high frequency components of magnetization energy.

Furthermore, as shown in Fig. 5, the read-only movable magnetic heads (3L) and (3R) do not tilt their gab parts themselves;
Since it moves vertically in parallel, the surface contact between the magnetic tape (20) and the gap surface is always maintained constant.

Therefore, contact noise can also be reduced.

Note that in the above embodiment, the movable playback head unit (
Two or more circular springs (102) in 100) may be provided, but it is necessary to select one that is highly elastic and reliable. Further, although a large number of slits are provided in the circular spring (lot) (102), the structure is not limited to this, and it is also possible to provide slits radially or to change the plate thickness.

Also, 2.1! The parallelism with the rotating shaft (10) is maintained by circular springs (101) and (102), but one end of the bobbin (103) is slidably held by three or more circular springs (101). By doing so, a circular spring (1
It is also possible to maintain parallelism using only 01).

In addition, the recording-only fixed magnetic heads (2L) and (2R) are made of amorphous material, and the reproduction-only movable magnetic heads (3L) and (3R) are made of ferrite material. ), (2R), (3
It is also possible to configure L) and (3R) from a recording optimum material and a reproduction optimum material, and in this case, even higher quality recording and reproduction can be performed.

Further, when the present invention is used for reproducing a magnetic tape on which signals are recorded using another magnetic recording/reproducing device, effects in terms of reproducing function can be obtained.

[Effects of the Invention] As described above, according to the present invention, by using a recording-only magnetic head with a wide gap width during recording, the magnetization power for the magnetic material on the magnetic tape is increased, and S /N deterioration can be prevented and high S/N recording can be performed. In addition, during playback, a magnetic head dedicated to playback with a narrower gap width than a magnetic head dedicated to recording is used, and by moving the magnetic head in the direction of the rotation axis of the rotating drum, high-frequency waves that are magnetized on the magnetic tape are In addition to being able to sufficiently pick up the components, it is also possible to accurately trace the recording track to prevent deterioration of S/N due to crosstalk interference, and to perform reproduction with high S/N and quality.

Therefore, it is possible to perform recording and reproduction with high S/N and high quality.

[Brief explanation of drawings]

FIG. 1A is a schematic plan view of a rotating drum device in a magnetic recording/reproducing apparatus according to an embodiment of the present invention, FIG. 1B is a characteristic diagram showing changes in magnetization power depending on the gap width of a recording-only magnetic head, and FIG. 2 is a rotational drum device. A longitudinal sectional front view of the drum device, FIGS. 3(a) and 3(b) are a perspective sectional view showing the specific structure of the head unit of the read-only movable magnetic head, and FIGS. 4(a) and 4(b) are longitudinal sectional front views of the drum device. ) is a plan view of a circular spring, FIG. 5 is an enlarged sectional view of the main part of FIG. 2, FIG. 6 is a configuration diagram of the drive section of a rotating drum device, and FIG. 7 is a rotating drum in a conventional magnetic recording/reproducing device. A schematic plan view of the device, FIG. 8 is a longitudinal sectional front view of the rotating drum device, FIG. 9 is a pattern diagram of recording tracks on the magnetic tape, and FIGS. 1OA and 10B explain the principles of recording and reproducing operations. This is a diagram. (1)...Rotating drum, (2L), (2R)...
・Fixed magnetic head for recording only, (3L), (3R)...
・Movable magnetic head for reproduction only (100)...Movable reproduction head unit. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] (1) A rotating drum, and a recording-only magnetic head and a reading-only magnetic head each independently attached to the rotating drum, and the gap width of the reading-only magnetic head is set to be larger than the gap width of the recording-only magnetic head. A magnetic recording and reproducing apparatus characterized in that the read-only magnetic head is configured to be small and movable in the direction of the rotation axis of the rotary drum.