JPH0869604A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE: To erase recorded contents of a magnetic tape by traveling the tape in the rewinding direction at high speed in the magnetic recording and reproducing device having a rotary head cylinder. CONSTITUTION: A high speed erasing head Ha or Hb is provided in its position as shown in the figure on the downstream side from the rotary head cylinder 3 in the traveling direction F of the magnetic tape T at the recording time. At the time of high speed erasing, the magnetic tape T is fed in the direction R at high speed, and the recorded contents are erased by the high speed erasing head Ha or Hb. Since the erasing head is positioned apart from the rotary head cylinder 3 toward the side of R2, contact between the magnetic tape T traveling in the direction R and the high speed erasing head is stabilized. Then, at the time of completing the erasing, the recorded contents are completely erased in a part in contact with the rotary head cylinder 3 without leaving any contents unerased. Then, at the high speed erasing time, by DC-erasing a sound track with a sound erasing head H2, after erasing at the time of 24-fold speed, audible band noise can be prevented from remaining unerased in the sound track.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus used for a VTR device and the like, and more particularly, to erasing recorded contents when the magnetic tape is running at high speed in the rewinding direction (REW direction). Magnetic recording / reproducing apparatus.

[0002]

2. Description of the Related Art FIG. 7 is a structural explanatory view of a magnetic recording / reproducing apparatus mounted on a VHS type VTR apparatus or the like. When the cassette pack C is loaded, the tape reels R1 and R2
Fits on the reel shaft of the magnetic recording / reproducing apparatus. Then, the tape pull-out mechanism having the loading posts 1 and 2 operates to pull out the magnetic tape T from the cassette pack C and wind it around the rotary head cylinder 3. When recording, the magnetic tape runs in the F direction (rew)
The direction is the R direction. A capstan 4, a pinch roller 5, and a guide post 6 are provided at a position downstream of the rotary head cylinder 3 when the magnetic tape T runs in the F direction. At the time of recording or reproduction, the magnetic tape T is run at a constant speed in the F direction by the rotation of the capstan 4. The running speed of the magnetic tape T during recording / reproduction is 3.34 cm / sec in the NTSC system and 2.34 cm / sec in the PAL system.

On the upstream side of the rotary head cylinder 3,
Guide rollers or posts 7 are provided, and tension posts 8 are also provided. The tension post 8 is fixed to the tension arm 9. The tension arm 9 is biased by a spring 10, and the tension post 8 is pressed against the magnetic tape T by this biasing force. When the tension of the magnetic tape traveling in the F direction fluctuates, the rotational position of the tension arm 9 is displaced according to the fluctuation. The displacement state of the tension arm 9 is detected by the detection unit, and the rotational load applied to the tape reel R1 on the supply side is adjusted accordingly, and the magnetic tape T running
The tension of will be kept almost constant.

A full width erasing head H1 is provided between the loading post 1 and the tension post 8. FIG.
Shows the full width erasing head H1 in a front view. The full-width erasing head H1 is provided with a magnetic gap G1 capable of covering the entire width in the width direction of the magnetic tape T, and at the time of recording, the recorded contents of the magnetic tape T can be erased in full width on the upstream side of the rotary head cylinder 3. Has become. A voice erasing head H2 is provided between the rotary head cylinder 3 and the capstan 4.
And a voice / control head H3.
At the time of recording, the voice track is erased by the magnetic gap (double gap) G2 of the voice erasing head H2. The voice / control head H3 is provided with a magnetic gap G3a for recording / reproducing a voice and a magnetic gap G3b for recording / reproducing a control signal. At the time of recording, voice recording is performed on the voice track erased by the voice erasing head H2 by the magnetic gap G3a.

[0005]

In the magnetic recording / reproducing device mounted on the VTR device, the recorded contents are erased by the full width erasing head H1 and the voice erasing head H2 at the time of recording as described above, and the rotary head cylinder 3 is immediately after erasing. An image signal and other signals are recorded by the on-board head, and an audio signal is recorded on the audio track and a traveling control signal (CTL signal) is recorded on the control track by the audio / control head H3. Also, recently, a VTR device capable of realizing a high speed erase mode has been desired. By performing the high-speed erasing operation, the magnetic tape can be initialized, and unnecessary recording contents can be immediately erased. Conventionally, in a magnetic recording / reproducing apparatus for a VTR device capable of this high speed erasing mode, high speed erasing is performed using a full width erasing head H1 shown in FIGS. That is, the magnetic tape T is run at a high speed in the same F direction as when recording, and the recorded contents of the magnetic tape T can be erased by the full width erasing head H1.

However, the conventional high speed erasing operation has the following problems. (1) In the method of erasing the magnetic tape T by running it in the F direction at a high speed, the magnetic tape is run in the F direction at a high speed for erasing and then the tape reel R1 on the supply side is reversely driven to remove the magnetic tape R. You have to rewind in the direction. Alternatively, in the case of a cassette pack in which the magnetic tape T is in the winding end state, the magnetic tape T is first rewound in the R direction, then is run at high speed in the F direction to perform high speed erasing, and the magnetic tape T is further wound. The operation of returning is required, the operation becomes complicated, and it takes time to complete the erasing.

(2) Therefore, it is conceivable to rewind the magnetic tape T in the R direction at a high speed and erase the recorded contents by the full width erasing head H1 at this time. However, the tension post 8 and the tension arm 9 provided in the magnetic recording / reproducing apparatus shown in FIG.
The purpose is to adjust the load on the supply reel R1 when the magnetic tape T travels in the F direction, and the tension post 8 is separated from the magnetic tape T when the magnetic tape T travels at a high speed in the R direction. When the tension post 8 is separated from the magnetic tape T in this manner, the tension of the magnetic tape between the guide roller 7 and the rotary head cylinder 3 fluctuates drastically, and the magnetic tape T and the full width erasing head H1 are magnetized. The contact with the gap G1 becomes unstable,
The magnetic tape T is easily erased and left unerased.

(3) Since the full width erasing head H1 is located upstream of the rotary head cylinder 3 in the conventional apparatus, the magnetic tape T is rewound at a high speed in the R direction for full width erasing. When an erasing operation by the head H1 is performed, when the rewinding of the magnetic tape is completed, the recorded contents of the magnetic tape T located between the full-width erasing head H1 and the rotary head cylinder 3 cannot be erased, and the magnetic tape T
There is an unerased portion at the beginning of.

(4) It is desirable that the high-speed erasing operation of the magnetic tape T be completed in a short time. Therefore, it is desired that the high-speed erasing of the magnetic tape T be carried out at a speed which is about 24 times as high as that at the time of recording and reproducing. It is rare. In the conventional high-speed erasing operation, the AC erasing operation of applying an AC current of about 200 kHz to the full-width erasing head H1 is performed.
When the AC tape is run at a speed of about 24 times and an AC erasing operation of 200 kHz is performed, the AC recording in the audible range of about 8 kHz is left on the magnetic tape T at the speed of 1 times (speed during recording / reproduction). . Therefore, when the magnetic tape T immediately after high-speed erasing is driven in the reproduction mode as it is, the magnetic gap G3a of the voice / control head H3 reproduces this signal, and noise in the audible range is generated.
In addition, when the unerased portion of the AC signal occurs in the audio track during recording, noise in the audible range is also generated during image reproduction. Further, if the frequency of AC erasing during high-speed erasing is increased to about 370 kHz, this AC signal at 1 × speed will be out of the audible range, and the problem of noise will disappear. However, if a high frequency alternating current is applied to the full width erasing head H1, the power supply circuit becomes large in size, not only the cost becomes high, but also the amount of heat generated by the core of the magnetic head increases.

(5) Full-width erasing head H1 during high-speed erasing
If a DC current is applied to the signal to perform DC erasing, the problem of noise in the audible range is eliminated. However, since the DC erasing is to make the polarity of the magnetic tape T equal to N or S, if a signal is recorded on the magnetic tape T, either N or S of the recorded signal, that is, either above or below the waveform of the AC recording signal is recorded. Distortion occurs and second-order distortion (second harmonic) occurs. In the Hi-Fi VTR device, the carrier of the L-channel and the R-channel of the Hi-Fi signal is 1.3 MHz and 1.7 M, respectively.
A 400 kHz component of the Hz difference is generated by the second-order distortion. The component of 400 kHz interferes with the low frequency conversion color signal (630 kHz), and beat noise is generated on the screen.

The present invention solves the above-mentioned problems of the prior art. The magnetic tape can be rewound to perform high-speed erasing. At this time, the contact between the erasing head and the magnetic tape is kept good, and the head of the magnetic tape is maintained. The purpose is to prevent the unerased part from being left.

Another object of the present invention is to prevent noise in the audible range from remaining or to prevent beat noise of an image signal from occurring when high speed erasing at about 24 times speed is performed. It

[0013]

The present invention relates to a magnetic recording / reproducing apparatus provided with a rotary head cylinder around which a magnetic tape pulled out from a cassette pack is wound, wherein the rotary head is in the magnetic tape running direction during recording. A high-speed erasing head is arranged at a position downstream of the cylinder, and when the magnetic tape runs at a high speed in a direction opposite to that at the time of recording, the high-speed erasing head erases the magnetic recording contents. Is.

The magnetic recording / reproducing apparatus of the present invention is mounted in a VHS system or an 8 mm system VTR device. The high speed erasing head has a magnetic gap extending in the width direction of the magnetic tape, and can have substantially the same structure as a conventional full width erasing head.

Further, when the voice erasing head and the voice recording / reproducing head are arranged at positions downstream of the rotary head cylinder in the running direction of the magnetic tape at the time of recording, the magnetic tape is When traveling at a high speed in the direction opposite to that at the time of recording, an alternating current is applied to the high speed erasing head to mainly erase the image record, and a direct current is applied to the voice erasing head to erase the voice record. That is, the area in which AC erasing for applying an alternating current is performed is both a recording area by helical scanning of a rotary head drum on a magnetic tape and a recording track of a CTL signal. Video signals are mainly recorded in the recording area by helical scan,
Besides, a horizontal synchronizing signal and the like are recorded. Also VHS Hi
In -Fi, an audio signal is also recorded in the helical scan area, and this is the same even in beta Hi-Fi and the like. In the present invention, the helical scan area and the control track in which the CTL signal is recorded are AC erased, and only the audio track is DC erased.

The audio recording / reproducing head is usually an audio / control head which is also used as a head for recording / reproducing a traveling control signal (CTL signal).
An audio recording / playback head that only performs audio recording / playback may be used.

The high speed erasing head can be arranged either upstream or downstream of the voice erasing head, but the high speed erasing head is located upstream of the voice erasing head, that is, between the rotary head cylinder and the voice erasing head. When arranged, it is preferable that the magnetic gap of the high-speed erasing head and the magnetic gap of the voice erasing head are formed at a position where they do not overlap each other with respect to the magnetic tape.

Further, the high-speed erasing head and the voice erasing head can be aligned with each other and fixed by joining, or the high-speed erasing head and the voice erasing head can be integrated into a common case. It is also possible to form a magnetic gap for high speed erasing and a magnetic gap for voice erasing.

[0019]

In the above means, the high speed erasing head is arranged downstream of the rotary head cylinder in the running direction of the magnetic tape during recording. In the high-speed erasing operation, the magnetic tape is run at high speed in the rewinding direction and the recorded contents of the magnetic tape are erased by the high-speed erasing head. In this high-speed erasing, the high-speed erasing head is located upstream of the rotary head cylinder with respect to the tape rewinding traveling direction. Therefore, during rewinding and running, fluctuations in the tension of the magnetic tape contacting the high-speed erasing head are reduced, the contact state between the high-speed erasing head and the magnetic tape is improved, and reliable erasing operation can be performed. Further, when the erasing by the rewinding operation is completed, the portion of the head portion of the magnetic tape that comes into contact with the rotary head cylinder has been erased, so that the unerased recorded contents do not occur in the head portion of the magnetic tape.

Further, for example, when erasing at a high speed of about 24 times, if an AC current is mainly applied to the high speed erasing head to mainly AC erase image recording, and a DC current is applied to the voice erasing head to DC erase the audio track. In addition, noise in the audible range due to AC erasure does not remain in the audio track, and signal distortion due to DC erasure does not occur in the recording area (helical scan area) for image signals and the like, and beat noise can be prevented.

In the above description, when the high speed erasing head is arranged between the rotary head cylinder and the voice erasing head, the magnetic gap of the high speed erasing head and the magnetic gap of the voice erasing head are relative to the magnetic tape. It is preferable to form them at positions that do not overlap each other. As a result, it is possible to prevent the audio track from being further AC-erased after the DC erasure, and the audio track can be reliably DC-erased.

Further, when the high speed erasing head and the voice erasing head are aligned with each other and fixed by joining, the relative position of the high speed erasing head and the voice erasing head can be set with high accuracy.

If the high speed erasing head and the voice erasing head are integrated and the magnetic gap for high speed erasing and the magnetic gap for voice erasing are formed in the common case, the number of magnetic heads Can be the same as before.
If three magnetic heads, a high-speed erasing head, a voice erasing head, and a voice recording / reproducing head (or a voice / control head), are provided adjacent to each other in the running area of the magnetic tape, when either magnetic head or Although the state of contact with the tape may deteriorate, the high-speed erasing head and the voice erasing head are integrated, and only two magnetic heads are provided adjacent to the magnetic tape running portion, so that both magnetic heads and magnetic tape The contact state of can be improved.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a VH of Hi-Fi as an embodiment of the present invention.
FIG. 3 is a plan view showing the structure of a magnetic recording / reproducing device mounted on an S-type VTR device. The tape reel R1 on the supply side and the tape reel R2 on the take-up side provided in the cassette pack C are fitted and installed in the reel shaft provided in the magnetic recording / reproducing apparatus. When cassette pack C is loaded,
The tape loading mechanism is started, and the magnetic tape T is pulled out from the cassette pack C by the loading posts 1 and 2 and wound around the rotary head cylinder 3.
The magnetic tape T is pulled out by the guide post 6a near the tape reel R2.

A capstan 4, a pinch roller 5 and the guide post 6 are provided on the downstream side of the rotary head cylinder 3 in the running direction (F direction) of the magnetic tape T during recording and reproduction.
a and another guide post 6b are provided. A guide roller or a post 7 is provided at a position upstream of the rotary head cylinder 3, and a tension post 8 and a tension arm 9 to which the tension post 8 is fixed are provided. The tension arm 9 is rotatably supported at its base, and is urged by a spring 10 in a direction of being pressed against the magnetic tape T. When the tension of the magnetic tape T traveling in the F direction changes, the position of the tension post 9 is displaced, the displacement amount is detected, and the load on the reel shaft on which the supply-side tape reel R1 is installed is increased or decreased. . As a result, the tension of the magnetic tape T running in the F direction is controlled to be substantially constant. Further, when the tape reel R2 is driven counterclockwise and the magnetic tape T runs in the rewinding direction (REW direction), that is, the R direction, the tension post 8 is separated from the magnetic tape T.

Next, the arrangement position of the fixed magnetic head will be described. A full width erasing head H1 is provided at a position on the upstream side of the rotary head cylinder 3 in the F direction (the tape running direction during recording / reproduction). The full width erasing head H1 is fixedly installed between the loading post 1 and the guide roller 7 in a state where the tape loading is completed. The full-width erasing head H1 is the same as the conventional example shown in FIG. 8, and has a magnetic gap G1 extending over the entire length of the magnetic tape T in the width direction. During recording on the magnetic tape T, an AC current of 70 kHz is applied to the full width erasing head H1 to AC erase the recorded contents of the magnetic tape T over the entire width.

A voice erasing head H2 and a voice / control head H3 are provided at positions downstream of the rotary head cylinder 3 when the running direction of the magnetic tape T is the F direction. Both heads H2 and H3 are the same as the conventional example shown in FIG. 9, and the same reference numerals are given to the examples shown in FIGS. 2 and 3. The voice erasing head H2 is located upstream of the voice / control head H3 in the running direction of the magnetic tape during recording. The voice erasing head H2 has a magnetic gap (double gap) G2 for scanning the voice track of the magnetic tape T. During recording, an AC current of 70 kHz is applied to the voice erasing head H2 to AC erase the voice track of the magnetic tape T.

The voice / control head H3 provided downstream of the voice erasing head H2 in the F direction is used both as a voice recording / reproducing head and as a control signal (CTL signal) recording / reproducing head. It is a thing. The voice / control head H3 has a magnetic gap G3a for recording / reproducing a voice signal and a magnetic gap G3b for recording / reproducing a control signal. The magnetic gap G3a for recording / reproducing an audio signal is
It is provided at the same track position as the magnetic gap G2 of the voice erasing head H2, and at the time of recording, the voice erasing head H2.
An audio signal is recorded by the magnetic gap G3a of the audio / control head H3 with respect to the audio track AC-erased by the magnetic gap G2. The magnetic gap G3b for recording / reproducing the control signal is arranged on the opposite side of the magnetic gap G3a in the tape width direction, and the control signal is recorded / reproduced on / from the control track opposite to the audio track.

The high-speed erasing head, which is a feature of the present invention, is provided downstream of the rotary head cylinder 3 in the tape running direction (F direction) at the time of recording / reproducing. The area where the high-speed erasing head is arranged is the area A from the tape pull-out position of the cassette pack C to the audio / control head H3, or the area B between the loading post 2 and the audio erasing head H2 when the tape loading is completed. It is either. In the area A, the high-speed erasing head is located at the position (a) between the tape withdrawing position of the cassette pack C and the guide post 6a, or the voice / control head H3.
And (b) between the guide post 6b and the guide post 6b. In the area B, the high speed erasing head is
Will be placed in the position.

In FIG. 2, the high speed erasing head Ha arranged at the position (a) is shown as a voice erasing head H2 and a voice erasing head H2.
It is shown in comparison with the control head H3. Figure 2
The high-speed erase head Ha shown in (1) has basically the same structure as the full-width erase head H1. The high-speed erasing head Ha can use the same one as the full-width erasing head H1, but the high-speed erasing head Ha has a magnetic gap longer than that of the full-width erasing head H1 in the width direction of the magnetic tape, and thus the full-width erasing head H1.
It is preferable to use one having a slightly longer vertical dimension. When the magnetic tape T is run at high speed by high-speed erasing, it is unavoidable that the magnetic tape T swings in the tape width direction. By making the high-speed erasing head Ha vertically long as described above, even if the magnetic tape T shakes, the full-width erasing can be surely performed.

The high-speed erasing head Ha has a magnetic gap Ga formed over the entire length of the magnetic tape T in the width direction. As shown in FIG. 2, the voice erasing head H2 and the voice / control head H3 are joined and fixed with their magnetic gap positions aligned, and the joined and fixed combination head is fixed to the head base 15. Since the full width erasing head Ha at the position (a) is arranged at a position distant from the voice erasing head H2 and the like, it is fixed on a head base 15a which is separate from the head base 15, and the head base 15a is magnetically recorded and reproduced. It is positioned and fixed to the chassis of the device. When the high speed erasing head is provided at the position (b) shown in FIG. 1, the high speed erasing head Ha having the same structure as shown in FIG. 2 is used.
Since the high-speed erasing head Ha arranged at the position (b) is provided close to the voice / control head H3, it is on the same head base 15 as the voice erasing head H2 and the voice / control head H3. , And three magnetic heads can be aligned and fixed on the head base.

Here, at the position of (a) or (b), as shown in FIG.
The operation of the magnetic recording / reproducing apparatus provided with the high speed erasing head Ha shown in FIG. Table 1 shows the currents applied to each erase head during recording and high-speed erase.

[0033]

[Table 1]

At the time of recording, the magnetic tape T is fed at a constant speed in the F direction by the rotation of the capstan 4, and the upper cylinder of the rotary head cylinder 3 rotates counterclockwise together with the magnetic head. The tape running speed during recording is 3.34 cm / sec in the NTSC system and 2.34 cm / sec in the PAL system.
sec. As shown in Table 1, during recording, an AC current of 70 kHz is applied to the full width erasing head H1 to AC erase the magnetic tape T in full width. On the magnetic tape T immediately after being erased, the magnetic head of the rotary head cylinder 3 helically scans and a signal is recorded. An image signal, a horizontal synchronizing signal, and the like are recorded in the recording area by the helical scan. Further, in VHS Hi-Fi and the like, an audio signal is also deeply recorded in a helical scan area. An AC current of 70 kHz is applied to the voice erasing head H2 to AC erase the voice track of the magnetic tape T, and a voice signal is recorded on the voice track by the magnetic gap G3a of the voice / control head H3. Further, the traveling control signal is recorded by the magnetic gap G3b.

When erasing the recorded contents of the magnetic tape T, the magnetic tape T is rewound (REW) direction (R direction).
Is sent at high speed. At this time, the high-speed erasing head Ha
An AC current of 0 kHz is applied, and AC erasing is performed over the entire width of the magnetic tape T. Also, the voice erasing head H2
Is applied with a DC current of 180 mA, and the audio track is DC erased. That is, the magnetic tape T travels in the R direction, and the high-speed erasing head H is first located on the upstream side in this travel direction.
AC erasing is performed over the entire width by a, and immediately thereafter, the audio erasing head H2 on the downstream side performs DC erasing of the audio track. The magnetic tape is fed in the R direction at the time of high-speed erasing. However, between the rotary head cylinder 3 and the capstan 4, that is, on the upstream side of the rotary head cylinder 3 when the magnetic tape T is running in the R direction, the magnetic tape T The tension at the time of running is stable, and the magnetic tape T is kept in stable contact with the high speed erasing head Ha and the voice erasing head H2. Therefore, the recorded contents of the magnetic tape T are surely erased by the high speed erasing head Ha and the voice erasing head H2. Also, when the magnetic tape T is all fed in the R direction,
Since the recorded contents are completely erased at the head portion of the magnetic tape T with which the rotary head cylinder 3 is in contact, there is no unerased portion at the head portion of the magnetic tape T.

Further, as described above, the full width of the magnetic tape T is first AC-erased by the high-speed erasing head Ha, and then the voice track is DC-erased by the voice erasing head H2. When high speed erasing is completed, the audio track is DC
Since it is in the erased state, even when high-speed erasing is performed at a high speed such as 24 times speed, there is no signal that remains in the audible range during reproduction in the audio track, and the audible range during reproduction is maintained. No noise is emitted.
Also, since the helical scan area, which is the recording area for image signals, is AC erased, there is no secondary distortion at the time of recording as in the case of DC erase of this area, and beat noise is generated on the screen. Can be prevented.

FIG. 3 shows the high-speed erasing head Hb when it is arranged at the position (C) in the area B. The high speed erasing head Hb is fixed to the head base 15 together with the voice erasing head H2 and the voice / control head H3. In this high-speed erasing head Hb, the voice erasing head H2
The dummy portion 16, that is, the portion where the magnetic gap is not formed is provided in the portion corresponding to the area of the magnetic gap G2 (the portion (d)), and the magnetic gap Gb is formed in the portion other than the dummy portion 16. That is, when the high speed erasing head Hb is arranged on the downstream side of the voice erasing head H2 in the magnetic tape T running in the R direction, the magnetic gap Gb of the high speed erasing head Hb and the magnetic gap G2 of the voice erasing head H2 are arranged. Are formed at positions that do not overlap each other in the width direction of the magnetic tape T.

In the high-speed erasing operation, the audio track is first recorded on the magnetic tape T running in the R direction and the audio erasing head H is used.
DC is erased by the second magnetic gap G2, and thereafter the DC is erased by the magnetic gap of the high-speed erase head Hb.
Areas other than the erased portion are AC erased. That is, the high-speed erasing head Hb prevents the voice tracks DC-erased by the voice erasing head H2 from being AC-erased on top of each other. The erasing current given to each head during erasing is the same as shown in Table 1. In FIG. 3, although the high speed erasing head Hb is located on the downstream side in the R direction with respect to the voice erasing head H2, A
The C signal is not left and DC is surely erased. Therefore, no audible noise remains on the audio track. In addition, since the recording area for the image signal and the like is AC erased, no secondary distortion remains when the image signal is recorded. Further, when the high speed erasing head is arranged at the position (a) or (b), it is possible to use the high speed erasing head Hb shown in FIG.

FIG. 5 shows another example of head arrangement using the same high-speed erasing head Hb as shown in FIG. In this embodiment, the voice erasing head H2, the voice / control head H3, and the high speed erasing head Hb are joined and fixed to each other. The three heads H2, H3, Hb are joined and fixed to each other with the positions of the magnetic gaps aligned, and the joined three magnetic heads are fixed to the head base 15. In this embodiment, the head base 15 is fixed to the chassis of the magnetic recording / reproducing apparatus, and when the position of the head base 15 is determined, three heads H are formed.
2 and H3 and Hb face the magnetic tape in a state where they are positioned with high precision.

In the embodiment shown in FIG. 6, the voice / control head H3 and the erasing head Hc are joined and fixed. The erasing head Hc is a combination of the voice erasing head H2 and the high speed erasing head Hb shown in FIG. More specifically, in a common case, a magnetic gap G2 for voice erasing and a magnetic gap Gb for high speed erasing are provided.
Is provided. Therefore, the magnetic gap Gb for high speed erasing and the magnetic gap G2 for voice erasing are
The magnetic tapes T are arranged at positions that do not overlap each other in the width direction. In FIG. 6, there are only two magnetic heads, H3 and Hc, and these two magnetic heads H3 and Hc.
The head base 15
Assembly is completed by fixing to.

When three magnetic heads are provided adjacent to each other as shown in FIG. 3, one of the magnetic heads such as the voice erasing head H2 and the magnetic tape T is provided as shown in FIG. A small gap δ is easily formed between
The contact between the magnetic gap of the voice erasing head H2 and the magnetic tape T becomes poor. On the other hand, if the magnetic head is composed of two magnetic heads as shown in FIG. 6, the magnetic tape T surely contacts both the magnetic gap Gb for high speed erasing and the magnetic gap G2 for voice erasing. A highly accurate erase operation can be performed. The present invention is based on the VHS as shown in FIG.
Is not limited to the magnetic recording / reproducing device of the 8 mm system,
The present invention can be applied to the R device and other types of magnetic recording / reproducing devices.

[0042]

As described above, according to the present invention, the high speed erasing head is arranged at the position downstream of the rotary head cylinder in the magnetic tape running direction during recording, and the high speed erasing operation is performed.
Since the magnetic tape is fed at a high speed in the rewinding direction, the contact between the high speed erasing head and the magnetic tape is stable in the high speed erasing operation. Moreover, when the high-speed erasing is completed, the unerased portion does not remain at the beginning of the magnetic tape.

If a high-speed erasing head is given an AC current to erase a recording area for image signals and the like and a voice erasing head is given a DC current to erase a voice track by DC, a speed of 24 times, for example, is obtained. Even if the erasing is performed at a high speed, no noise in the audible range remains on the audio track, and no beat noise occurs in the recording area such as the image signal.

The magnetic gap of the high-speed erasing head,
When the magnetic gap of the voice erasing head is formed at a position where it does not overlap with the magnetic tape, the high speed erasing head may be provided downstream of the voice erasing head during high speed erasing. , The audio track is DC
It is erased, and the above audible noise does not remain.

Further, in the structure in which the high speed erasing head and the voice erasing head are aligned with each other and fixed by joining,
Both magnetic heads can be accurately aligned with the magnetic tape.

Further, in the structure in which the high speed erasing head and the voice erasing head are integrated and the magnetic gap for high speed erasing and the magnetic gap for voice erasing are formed in the common case, the number of magnetic heads is minimized. In addition, the contact state between the erasing head and the magnetic tape is stable.

[Brief description of drawings]

FIG. 1 is a plan view showing the structure of a magnetic recording / reproducing apparatus according to an embodiment of the present invention,

FIG. 2 is a front view of each magnetic head when a high-speed erasing head is provided in an area A,

FIG. 3 is a front view of each magnetic head when a high-speed erasing head is provided in a region B,

FIG. 4 is an enlarged plan view showing a contact state between each magnetic head and the magnetic tape of the embodiment shown in FIG.

FIG. 5 is a front view showing a state in which three magnetic heads are integrally joined and fixed;

FIG. 6 is a front view showing an embodiment in which a high speed erasing head and a voice erasing head are integrated.

FIG. 7 is a plan view showing the structure of a conventional magnetic recording / reproducing apparatus,

FIG. 8 is a front view showing a full width erasing head,

FIG. 9 is a front view showing a voice erasing head and a voice / control head,

[Explanation of symbols]

 1, 2 Loading post 3 Rotating head cylinder 4 Capstan 6a, 6b Guide post 8 Tension post C Cassette pack T Magnetic tape H2 Voice erasing head H3 Voice / control head Ha, Hb High speed erasing head G2 Voice erasing magnetic gap Ga, Gb high speed magnetic gap

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuyuki Yamada 3-12 Moriya-cho, Kanagawa-ku, Yokohama, Kanagawa Japan Victor Company of Japan, Ltd. (72) Inventor Moruichi 3-chome, Moriya-cho, Kanagawa-ku, Yokohama Address 12 Victor Company of Japan, Ltd.

Claims (5)

[Claims] 1. A magnetic recording / reproducing apparatus provided with a rotary head cylinder around which a magnetic tape drawn out from a cassette pack is wound, at a position downstream of the rotary head cylinder in the running direction of the magnetic tape during recording. A magnetic recording / reproducing apparatus, in which a high-speed erasing head is disposed, and when the magnetic tape runs at a high speed in a direction opposite to that at the time of recording, the high-speed erasing head erases magnetic recording contents. 2. An audio erasing head and an audio recording / reproducing head are arranged at positions downstream of the rotary head cylinder in the running direction of the magnetic tape at the time of recording, and the magnetic tape is driven at a high speed in a direction opposite to that at the time of recording. 2. The magnetic recording / reproducing apparatus according to claim 1, wherein an alternating current is applied to the high speed erasing head to mainly erase the image recording, and a direct current is applied to the voice erasing head to erase the audio recording when traveling. 3. The high speed erasing head is arranged between the rotary head cylinder and the voice erasing head, and the magnetic gap of the high speed erasing head and the magnetic gap of the voice erasing head do not overlap each other with respect to the magnetic tape. The magnetic recording / reproducing apparatus according to claim 2, which is formed. 4. A magnetic recording / reproducing apparatus according to claim 2, wherein the high-speed erasing head and the voice erasing head are aligned with each other and fixed by joining. 5. The magnetic recording according to claim 1, wherein the high speed erasing head and the voice erasing head are integrated, and a magnetic gap for high speed erasing and a magnetic gap for voice erasing are formed in a common case. Playback device.