JPH0836703A - Magnetic erasing apparatus - Google Patents

Abstract

PURPOSE:To erase data at a high speed without generating noises or harmonic distortions when data are recorded again, by setting a DC eraser head and an AC eraser head in one unit and erasing a plurality of recording tracks simultaneously. CONSTITUTION:The eraser head 11 is constituted of a linear audio eraser head 12. a video/control track eraser head 13, a linear audio recording/reproducing head 14 and a control signal-recording/reproducing head 15 in one body. An AC signal of a predetermined frequency is supplied to the eraser head 13 from an AC transmission circuit not shown, thereby a video track and a control signal track are erased by the AC. The linear audio eraser head 12, when receiving a DC signal, erases signal components of audible zones recorded to a magnetic tape at a high-speed erasing time. At a normal recording time, an AC erasing signal is supplied to the head 12 from a pre-erasing/oscillating circuit not shown, thereby a linear audio track is erased by the AC, enabling recording of an audio signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic erasing device suitable for high speed erasing of a recording medium such as a magnetic tape.

[0002]

2. Description of the Related Art Generally, a so-called home VTR is a linear audio track formed on a magnetic tape by a full width erasing head when recording a video signal and an audio signal on a magnetic recording medium such as a magnetic tape. The video track and the control track are erased, and a recording / reproducing head mounted on the rotary head records a HiFi audio signal in a deep layer of a predetermined video track of a magnetic recording medium such as a magnetic tape and records the video signal as the HiFi audio signal. Is recorded on the linear audio track by a fixed audio head.

With the widespread use of such VTRs for home use, a user can easily record video and audio signals on a magnetic recording medium such as a magnetic tape housed in a video cassette, while the number of tape cassettes once recorded. There is a growing need for efficient use of tape cassettes.

Therefore, as an efficient use of the above-mentioned tape cassette, all the signals recorded on the magnetic tape of the recorded tape cassette whose recorded contents are no longer needed are erased (initialized) at high speed. By doing so, the emergence of a magnetic erasing device capable of reusing a tape cassette in a state close to that when the tape cassette is used for the first time has been desired.

[0005]

Conventionally, when erasing a signal recorded on a magnetic tape, AC erasing is performed by an AC signal supplied from an AC signal generator to an erasing head, and erasing from a constant current circuit. There is DC erasing, etc. in which erasing is performed by a DC signal supplied to the head. If an erasing signal having a frequency sufficiently higher than the running speed (erasing speed) is used, AC erasing is most desirable for signal erasing of this magnetic tape. .

However, when performing high-speed erasing of a magnetic recording medium such as a magnetic tape, in the above-mentioned AC erasing, since the running speed of the magnetic tape is high, the erasing head generates heat due to the increase of the frequency of the erasing signal, so that the erasing signal is generated. Since there is a limit to increasing the frequency, sufficient recording demagnetization cannot be obtained for a magnetic tape running at high speed, and an erasing signal is recorded on the magnetic tape. Therefore, when the normal reproduction is performed later, the erase signal having a high frequency is reproduced by the audio head as an audio signal of a low frequency, which is reproduced as noise.

In the above DC erasing, high speed erasing can be performed regardless of the running speed of the magnetic tape, but since the magnetic layer of the magnetic tape is magnetized in one direction, the video signal and the When a HiFi audio signal is recorded, there is a drawback that even-order harmonic distortion is generated between the full width erasing head and the magnetic head, which performs full recovery of the video signal and the HiFi audio signal during normal recording, which adversely affects the video signal. (However, even at this time, even-order harmonic distortion also occurs in the linear audio track, but during normal recording, the AC erasing head dedicated to the linear audio track, which is provided immediately before the linear audio recording / playback head, performs pre-erasing. On the other hand, the erasing head for DC erasing described above is installed at a position distant from the AC erasing head dedicated to the linear audio track. It is the even order harmonic distortion occurs in the linear audio track between the AC erase head erase head).

Therefore, the video signal of the DC erasing signal and Hi
The magnetic recording medium is erased by an AC signal in consideration of the influence on the Fi audio signal, and the linear audio track of the magnetic recording medium is erased by a DC signal in consideration of the influence of the AC erase signal on the linear audio track. By doing
It has been desired to develop a magnetic erasing device which improves the influence of the normal reproduction on the video signal, the HiFi audio signal and the linear audio to be recorded thereafter and performs high speed erasing as compared with the prior art.

On the other hand, a tape recorder erasing method in which a DC erasing head, an AC erasing head and a recording head are arranged in this order along the running direction of the magnetic tape (Japanese Patent Laid-Open No. 58-58).
No. 200408), a full-width erasing head and a voice erasing head are both DC erasing heads, and an erasing device of a video signal recording / reproducing device having a switching contact for switching these (Japanese Utility Model Publication No. 57-94610) and a full erase head ( Although a magnetic recording device using a DC erasing head as a full width erasing head (Japanese Utility Model Laid-Open No. 58-105012) has been proposed, no disclosure has been made regarding the magnetic erasing device as described above.

[0010]

In order to solve the above problems, the present invention provides a magnetic recording medium having the following configurations (1) to (3). (1) A magnetic erasing device including a plurality of erasing heads for erasing signals recorded on a plurality of recording tracks formed on a magnetic recording medium, wherein at least one recording is performed on the plurality of recording tracks. A DC erasing head for erasing a track with a DC current, and an AC erasing head for erasing at least one recording track of the plurality of recording tracks with an AC current are used. When erasing the signals recorded on the plurality of recording tracks, the magnetic recording medium is run at a higher speed than when the signals are normally erased, and the plurality of recording tracks are erased simultaneously. Erase device. (2) A magnetic erasing device including a plurality of erasing heads for erasing signals recorded on a plurality of recording tracks formed on a magnetic recording medium, wherein at least a linear audio track among the plurality of recording tracks. A DC erasing head for erasing data by a DC current, and an AC erasing head for erasing at least a video track and a control signal track among the plurality of recording tracks by an AC current. When the signals recorded on the plurality of recording tracks are erased, the magnetic recording medium is run at a higher speed than when the signals are normally erased to simultaneously erase the plurality of recording tracks. Magnetic eraser. (3) A magnetic erasing device comprising a plurality of erasing heads for respectively erasing signals recorded on a plurality of recording tracks formed on a magnetic recording medium, wherein a linear audio track among the plurality of recording tracks. A direct current erasing head for erasing the video track and the control signal track among the plurality of recording tracks by an alternating current, and using the direct current erasing head and the alternating current erasing head. When the signals recorded on the plurality of recording tracks are made to travel on the magnetic recording medium at a higher speed than when the signals are normally erased to simultaneously erase the plurality of recording tracks respectively, the traveling direction of the magnetic recording medium On the other hand, the DC erasing head and the AC erasing head are provided prior to the recording head for recording signals on the plurality of recording tracks. Magnetic erasing device to be a characteristic.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic configuration diagram of a magnetic tape running system of a magnetic erasing device according to the present invention, FIG. 2 is a diagram for explaining a first embodiment of an erasing head which is an essential part of the present invention, and FIG. FIG. 4 is a circuit diagram for explaining an erasing head which is an essential part of the present invention, and FIG. 4 is a schematic configuration diagram of a magnetic tape running system for explaining a second embodiment of the magnetic erasing device according to the present invention. Further, the same components as those described above are designated by the same reference numerals, and the description thereof will be omitted.

A first embodiment of the magnetic erasing device according to the present invention and a second embodiment of the magnetic erasing device according to the present invention will be described below with reference to FIGS.

(First Embodiment) As shown in FIG. 1, the magnetic erasing apparatus of the present invention feeds a magnetic recording medium (hereinafter referred to as a magnetic tape T) stored in a tape cassette (not shown) to a winding side. A guide pole 3a for guiding the traveling of the magnetic tape T sent from the SP reel 1, a full width erasing head 2 for erasing the full width of the magnetic tape T sent through the guide pole 3a, an image on the full width erased magnetic tape T , Magnetic heads 8a, 8 for recording HiFi audio signals
18 on the peripheral surface of the rotary drum 4 on which b, 8c and 8d are mounted.
Guide poles 3b, 3c wound around a range of 0 °,
A linear audio erasing head 12 for pre-erasing a linear audio track on the magnetic tape T, a video / control track erasing head 13 described later, and a linear audio recording / reproducing head 14 for recording / reproducing an audio signal on / from the linear audio track. And a control signal recording / reproducing head 15 for recording and reproducing a control signal on the control track.
Are integrally formed, a pinch roller 5 and a capstan 6 which sandwich the magnetic tape T and run the magnetic tape T at a predetermined running speed. Thus, the magnetic tape T passing through the pinch roller 5 and the capstan 6 is the winding side T of the tape cassette described above.
It is wound by the U reel 7.

Here, the above-described full-width erasing head 2 is for performing pre-erasure of the magnetic tape T when the input video and audio signals are normally recorded on the magnetic tape T (during normal recording). The magnetic heads 8a to 8d are for recording video and HiFi audio signals on the magnetic tape T on which the pre-erasure has been performed. And this magnetic head 8
Reference numerals a to 8d are for reproducing the video and the HiFi audio signal recorded on the magnetic tape T during signal reproduction. Also,
In the erasing head 11 described above, the linear audio erasing head 12 erases a linear audio track by an erasing signal which is switched between high speed erasing and normal recording, which will be described later, and the linear audio recording / reproducing head 14 linear audio during normal recording. The erasing head 12 records a normal audio signal on the linear audio track pre-erased and reproduces it during normal reproduction. Further, the control signal recording / reproducing head 15 records a control signal on a control track during normal recording and reproduces it during normal reproduction. The video / control track erasing head 13 carries out AC erasing of the video / control track during high-speed erasing according to the present invention.

In the following, the high-speed erasing operation of the magnetic erasing apparatus according to the present invention will be described. For the sake of convenience, in the recorded tape cassette for high-speed erasing, the magnetic tape T is wound around the supply side SP reel 1 and in this state. Fast forward this (F
High-speed erasing shall be performed in the F) direction.

The magnetic tape T sent from the above-mentioned supply side SP reel 1 is fed through the guide pole 3c as shown in FIG.
As shown in FIG. 5, magnetic erasing is performed by the erasing head 11 described above, and the magnetic data is supplied to the pinch roller 5 and the capstan 6. At this time, the linear audio erasing head 12 of the erasing head 11 functions as a DC erasing head to DC erasing the linear audio track, and the video / control track erasing head 13 as an AC erasing head AC erasing the video / control track. However, in FIG. 2, the heads constituting the erasing head 11 are illustrated on the surface opposite to those in contact with the magnetic tape T in order to explain each head, but in reality, these heads are in contact with the magnetic tape T. Is.

When the erasing operation of the magnetic erasing apparatus is performed, the video / control track erasing head 13 is set to
As shown in (A), an AC signal from the AC oscillator circuit 22 is supplied to AC erase the video track and the control signal track. Here, if the oscillation frequency of the erase signal is set high, the voltage amplitude applied to the erase head becomes high and the material of the erase head itself generates heat. Therefore, there is a limit to setting this oscillation frequency high. It is necessary to set the running speed of the magnetic tape.

Therefore, at least during normal reproduction, an erasing signal is recorded at a frequency (for example, 1.3 MHz) that does not include 629 kHz ± 500 kHz, which is the band of the low-frequency conversion carrier color signal of the video signal to be FM-modulated and recorded. To set the running speed of the magnetic tape. Incidentally, since the band of the luminance signal of the video signal to be FM-modulated and recorded is sufficiently higher than that of the low-frequency conversion carrier color signal with respect to this erase signal, there is no problem. Further, the frequency band of the HiFi voice recorded by FM modulation is 1.15 to 1.85 MHz, but there is no influence due to the azimuth loss of the magnetic head.

Thus, for example, an oscillation frequency of 200 kHz
Using the AC signal of z as the erasing signal, the magnetic tape T is VTR
(For example, a VHS (trademark) type VTR) is run at 24 times the normal running speed (standard mode), a signal of about 1.3 MHz is newly recorded on the magnetic tape T, and this signal is magnetic. Even if the tape T is reproduced during normal reproduction, the video signal is not adversely affected, and the effect that the signal is erased is obtained.

By performing this erasing operation at the above running speed, for example, a VHS (trademark) type tape cassette which can be recorded and reproduced for 2 hours can be erased in about 5 minutes.

However, if the above-mentioned AC signal of 200 kHz is recorded on the magnetic tape at 24 times the normal running speed, the video signal is erased. On the other hand, when the magnetic tape is normally reproduced, the linear audio recording / reproducing head is used. 14 audible signal components (for example, a frequency of about 8.3 kHz)
Since z) is reproduced as noise, the DC signal from the DC current circuit 24 is supplied to the linear voice erasing head 12 at the time of high speed erasing as shown in FIG. Performs DC erasure to eliminate signal components.

During normal recording (when recording a voice signal), it is necessary to supply an AC erasing signal from the pre-erase signal oscillating circuit 23. A capacitor C ₁ is provided so as not to flow. That is, at the time of high speed erasing, the DC signal from the DC current circuit 24 is supplied to the linear voice erasing head 12 to erase the linear voice track. At this time, as described above, since the linear audio track is magnetized in one direction by the DC signal, harmonic distortion occurs. However, during normal recording, the AC erasing signal from the pre-erase oscillating circuit 23 is applied to the linear audio head 1.
2, the audio signal can be recorded by erasing the linear audio track by alternating current, so that in practice (for example, recording video / audio in a high-speed erased tape cassette), the influence of harmonic distortion is eliminated. .

In this way, a high-speed (for example, VHS (trademark) type V tape) of a recorded tape cassette whose recorded contents are no longer needed.
The magnetic tape is run at 24 times the standard mode of TR)
It becomes possible to erase, and the tape cassette can be reused in a state close to the first use without being affected by noise and harmonic distortion.

In the normal tape cassette, the magnetic tape is wound around the supply side SP reel 1 and the take-up side TU reel 7 via the leader tape portion having no magnetic layer, so that the magnetic tape T is sufficiently supplied. Since the magnetic tape T is erased at high speed by the erasing head 11 via the leader tape portion in the state of being wound on the SP reel 1,
The unerased portion at the beginning of recording on the magnetic tape T can be eliminated.

In the high-speed erasing described above, the recorded tape cassette in which the magnetic tape T is wound around the supply-side SP reel 1 is high-speed erasing in the fast-forward (FF) direction. It goes without saying that the recorded tape cassette in which the magnetic tape T is wound around 7 may be erased at high speed in the rewinding (REW) direction.

(Second Embodiment) The erasing head 11 used in the first embodiment is a linear voice erasing head 12 for pre-erasing a linear voice track as described above.
A video / control track erasing head 13, a linear audio recording / reproducing head 14 for recording / reproducing an audio signal on a linear audio track, and a control signal recording / reproducing head 15 for recording / reproducing a control signal on a control track are integrally configured. Therefore, for example, it is necessary to integrally form the linear audio erasing head 12 and the video / control track erasing head 13 with high accuracy.
The development of such a new erasing head has a problem that the manufacturing cost of the popular VTR becomes high, for example.

Therefore, the full width erasing head 2 used in the above magnetic tape running system is replaced with the above high speed AC erasing head, and the erasing head 11 is a known VT.
To provide a magnetic erasing device for performing the above-mentioned high-speed erasing with a simple configuration by replacing the audio / control head of R and replacing the linear audio erasing head of the audio / control head with the above-mentioned linear audio erasing head 12. You can

In the second embodiment, as shown in FIG. 4, by supplying the AC signal from the AC oscillation circuit 22 as shown in FIG. 3A to the full width erasing head 2 shown in FIG. This is referred to as a full width AC erasing head 31, and the above erasing head 11 is used as the audio / control head 3
Replace with 2. The audio / control head 32 supplies an erasing signal from the pre-erase signal oscillating circuit 23 and the direct current circuit 24 to a linear voice erasing head of a known VTR audio / control head, respectively, as shown in FIG. By doing so, like the linear voice erasing head 12, direct current erasing is performed during high-speed erasing, and pre-alternating AC erasing is performed during normal erasing.

At this time, the full-width AC erasing head 31 described above is used.
Is operated during high-speed erasing in the FF direction, the high-speed erasing in the FF direction described above can be performed from the beginning of recording of the magnetic tape T wound around the supply side SP reel 1. On the other hand, by providing an AC erasing head having the same structure as the full-width AC erasing head 31 as the full-width AC erasing head 33 between the pinch roller 5 and the capstan 6 and the take-up TU reel 7 described above, R
High-speed erasing in the EW direction can be performed. here,
With respect to the above-described full-width AC erasing head 31, only by supplying the AC erasing signal described above at the time of high-speed erasing in the FF direction,
The entire width of the magnetic tape T wound around the supply side SP reel 1 can be AC erased from the beginning of recording signals (video, HiFi audio signal and normal audio signal). Also,
Regarding the above-described full-width AC erasing head 33, the magnetic tape T wound around the supply-side TU reel 7 may be provided only by supplying the AC erasing signal described above during high-speed erasing in the REW direction.
The full width of AC can be erased from the end of signal recording. The magnetic tape T which has been subjected to high-speed AC erasing in the FF direction and the REW direction is subjected to DC erasing of the linear audio track in the audio / control head 32, and the audible signal components generated by the high-speed AC erasing are erased. .

Thus, in the present magnetic erasing apparatus, the full width AC erasing head 31 for the FF direction and the full width AC erasing head 33 for the REW direction are used in the audio / control head 32 without using the special erasing head 11. The linear voice erasing head 12 makes it easy to perform FF.
Since high-speed erasing in both the REW direction and the REW direction can be performed, even when a new video / audio signal is recorded after the above-mentioned high-speed erasing, the cross-beat of the video signal due to the erased remaining signal at the beginning of recording, switching noise of the HiFi audio signal, etc. Can be removed.

The full-width AC erasing heads 31 and 3 described above are used.
3 is a position where the recording start and the recording end of the signal on the magnetic tape T are surely erased, so that the magnetic tape T can always be erased in front of the rotary drum 4 in each direction. If so, it goes without saying that the position is not limited to the above-mentioned position.

The high-speed erasing described above eliminates the inconvenience that a signal component in the audible range is generated in the linear audio track on which the AC erasing has been performed. It goes without saying that the erase head is not limited to the above position as long as the erase head is arranged.

Since the normal audio signal is recorded on the linear audio track immediately after the pre-erasure is performed during the normal recording, the linear audio track is hardly affected by the above-mentioned even-order harmonic distortion. Since it is not necessary to perform DC erasing after performing AC erasing on, a high-speed DC erasing head for erasing DC of the linear audio track during high-speed erasing,
Of course, a high-speed AC erase head for AC-erasing the video / control track may be separately provided.

[0034]

As described above, according to the structure of the present invention as set forth in claim 1, when erasing the magnetic recording medium, the signals recorded on a plurality of recording tracks are erased by alternating current. Can be erased at high speed, and the noise component reproduced from the recording track erased by AC can be completely removed by DC erase, so that the magnetic recording medium can be initialized and the recorded contents There is an effect that the magnetic recording medium which has become unnecessary can be effectively used.

According to the structure of the present invention as set forth in claim 2, in addition to the above-mentioned effect, the linear audio track among the plurality of recording tracks which have been erased at high speed by AC erasing can be erased at high speed by DC erasing. This makes it possible to completely remove the noise component reproduced from this linear audio track after AC erasing, so even if the signal is recorded again on the magnetic recording medium that has been subjected to high-speed erasing and is reproduced, the video signal and linear This has the effect of not adversely affecting the audio signal.

Further, according to the structure of the present invention as set forth in claim 3, in addition to the above effects, a DC erasing head and a DC erasing head are provided prior to the recording head for recording signals on a plurality of recording tracks formed on the magnetic recording medium. By providing the AC erasing head, the unerased signal on the magnetic recording medium that has been erased at high speed can be removed, so even if the signal is recorded again and reproduced, the image signal There is an effect that it is possible to record good video signals and audio signals from which cross beats, switching noise of audio signals, and the like are removed.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a magnetic tape running system of a magnetic erasing device according to the present invention.

FIG. 2 is a diagram for explaining a first embodiment of an erasing head which is an essential part of the present invention.

FIG. 3 is a circuit diagram for explaining an erase head that is a main part of the present invention.

FIG. 4 is a schematic configuration diagram of a magnetic tape running system for explaining a second embodiment of the magnetic erasing device according to the present invention.

[Explanation of symbols]

 12 DC erasing head 13 AC erasing head 8a, 8b, 8c, 8d Magnetic head T Magnetic recording medium (magnetic tape)

Claims (3)

[Claims] 1. A magnetic erasing apparatus comprising a plurality of erasing heads for erasing signals recorded on a plurality of recording tracks formed on a magnetic recording medium, wherein at least one of the plurality of recording tracks is provided. A direct current erasing head for erasing one recording track with a direct current; and an alternating current erasing head for erasing at least one recording track of the plurality of recording tracks with an alternating current. When erasing the signals recorded on the plurality of recording tracks by using the magnetic recording medium, the magnetic recording medium is run at a higher speed than when the signals are normally erased to simultaneously erase the plurality of recording tracks. Magnetic erasing device. 2. A magnetic erasing device comprising a plurality of erasing heads for respectively erasing signals recorded on a plurality of recording tracks formed on a magnetic recording medium, wherein at least a linear portion of the plurality of recording tracks is provided. A DC erasing head for erasing an audio track with a DC current, and an AC erasing head for erasing at least a video track and a control signal track with an AC current among the plurality of recording tracks, the DC erasing head and the AC erasing head When erasing the signals recorded on the plurality of recording tracks by using, the magnetic recording medium is run at a higher speed than when the signals are normally erased to simultaneously erase the plurality of recording tracks. And magnetic erasing device. 3. A magnetic erasing device comprising: a plurality of erasing heads for respectively erasing signals recorded on a plurality of recording tracks formed on a magnetic recording medium; A DC erasing head for erasing an audio track with a DC current; and an AC erasing head for erasing a video track and a control signal track among the plurality of recording tracks with an AC current. When the signals recorded on the plurality of recording tracks are used to erase the plurality of recording tracks simultaneously by running the magnetic recording medium at a higher speed than when the signals are normally erased, The DC erasing head and the AC erasing head are provided prior to the recording head that records signals on the plurality of recording tracks in the traveling direction. Magnetic erasing apparatus according to claim and.