JPS5925291B2 - magnetic tape device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic tape device that records and reproduces a signal for identifying a recording position (hereinafter referred to as a cue signal).

Recent magnetic tape devices have advanced in high-density recording, making it possible to record and play back 4 to 6 hours on a single cassette tape. It became necessary.

In many conventional consumer magnetic tape devices, the number of rotations of the tape supply reel disk, tape take-up reel disk, etc. is counted to find the beginning, but this must be done from the start point of the tape in the cassette tape. It was impossible to cue from the middle of the tape. Again 1
It was also impossible to insert multiple cue signals into a single cassette tape and to automatically search for them. Furthermore, in the case of a cassette tape, during normal recording or playback operation mode, the tape is pulled out from inside the cassette and loaded onto the rotating drum (loading state), so a cue signal head is provided in this loading path. This had the disadvantage of making the entire device complicated and expensive. In fast forwarding and rewinding operation modes that require cueing operations, the tape is generally unloaded to avoid undue force on the tape, and in this case the tape speed is also increased.
As described above, the running path of the tape is different between the loading state and the unloading state, and the cueing function is related to both states, which causes various difficulties. Also, when fast forwarding or rewinding operations are performed while the loading state is in progress, installing a new recording head and playback head for cueing signals within the tape running path requires a larger tape running path, which requires tape guides and pins. etc., resulting in an increase in the size and cost of the entire magnetic tape device. The present invention has been made in view of the above-mentioned drawbacks, and it is an object of the present invention to provide a magnetic tape device with an added cueing function.

An embodiment of the present invention will be described in detail below with reference to the drawings.
FIGS. 1 and 2 show an embodiment of a magnetic tape device having a cueing function according to the present invention. Figure 1 shows the tape running system in parallel loading mode recording and playback mode (loading state). In the figure, 1 is a rotating drum equipped with two video heads, and 1a and lb are the surroundings of this rotating drum 1. This is a video head that slightly protrudes from and is fixed to the video head and rotates at high speed together with the rotating drum 1. The video heads 1a and 1b are each exactly 18 mm relative to the center of the drum.
It is indexed to the position of 0. 2a, 2b, 2c are loading tape guides on the supply side, 2a', 2b'
, 2c' are loading tape guides on the take-up side, both of which function to stably load the magnetic tape 3 on the rotating drum 1. The four guides 2b, 2c, 2b', and 2c' are as shown by the arrows. During the loading operation, the magnetic tape 3 is moved while being pulled out.

4a is a guide roller on the supply side, and 4b is a guide roller on the take-up side, which are impedance rollers for reducing small vibrations of the magnetic tape and jitter.

Reference numeral 5 denotes a head for recording a cue signal, which performs saturation recording on the magnetic tape 3 when a cue signal consisting of a low frequency signal is applied.

Furthermore, when a recording operation mode for recording video and audio signals is specified and no cue signal is applied, it operates as a full-width erasing head. 6 and 7 are tape guides, and 8 is a tape tension regulator.

Reference numeral 9 denotes an audio erasing head, and 10 an audio signal/control signal head. Generally, the audio erasing head 9 and the audio signal/control signal head 10 are integrated to provide mechanical precision.

11 is a tape guide, 12 is a pinch roller, 13 is a capstan, the magnetic tape 3 is sandwiched between the pinch roller 12 and the capstan 13, and the capstan 1
The rotation of 3 causes it to move in the direction of the arrow at a constant speed.

14 is a force set in which the magnetic tape 3 is stored.

Reference numerals 15, 16, and 17 are tape guides that are present in the force set and are used to smoothly supply and wind up the stored magnetic tape 3.

18 is a supply reel in the force set, and 19 is a take-up reel in the force set.

Reference numeral 20 denotes a cue signal reproducing head for reproducing cue signals, which is installed on the main deck, and when the force set 14 is mounted on the magnetic tape device main body, the magnetic surface of the magnetic tape 3 in the force set 14 is reproduced. It makes contact with the back side.

In the magnetic tape device configured as described above, the magnetic tape 3 runs as shown in FIG. It contacts the magnetic surface of the tape 3 and performs its respective operations. The cue signal recording head 5 also operates as a full-width erasing head in the normal recording operation mode. FIG. 2 shows a tape running system in the rewind/fast forward operation mode of the parallel loading system, and the same reference numerals as in FIG. 1 indicate the same or corresponding parts.

The loading guides 2a, 2c on the supply side and the loading guides 2b', 2c' on the take-up side are housed in the force set 14 as shown by solid arrows, and the tape guide 7
The magnetic tape 3 also falls within the force set 14 as shown by the dotted arrow.
is supplied from the supply reel 18 to the take-up reel 19 via tape guides 15, 16, 17 provided within the force set. Conversely, when the loading operation is started, the loading tape guides 2b, 2c, 2b', 2
c' and the tape guide 7 are moved as shown by the arrows to the positions shown in FIG. 1, and the magnetic tape is mounted on the rotating drum.
During rewinding and fast-forwarding operations, the tape runs at a speed 20 to 30 times faster than in the recording and playback modes in the tape running state shown in FIG.

The supply reel 18 rotates at high speed in the rewind mode, and the take-up reel 19 rotates at high speed in the fast forward mode. In both of these modes (rewind and fast forward), the cue signal reproducing head 20 always comes into contact with the back side of the magnetic tape 3 and detects the cue signal recorded on the magnetic surface, and this detection signal triggers the auto-stop plunger. (not shown) to stop the rotation of the reels 18 and 19, respectively, and it becomes possible to locate the beginning of the magnetic tape 3 at a predetermined position.

FIG. 3 shows a magnetic tape pattern. 3a and 3b are audio signal tracks, 3c is a video signal track, and 3d is a cue signal recorded superimposed on the video signal track, for example, a square wave signal of about 20 Hz. It is.

3e is a control signal track.

Now, to discuss the cue signal, firstly, the cue signal recording head 5 operates as a full-width erase head in the normal recording operation mode, but when a recording position designation operation is performed,
A square wave signal of z is applied for about 0.5 seconds, and this cue signal is recorded on the magnetic tape 3 in a saturated recording state.

At this time, it is possible to record with the full width of the full width erase head, but it is preferable to switch the recording width so as not to affect the audio signal track and the control signal track as shown in FIG. That is, as shown in FIG. 3, the cue signal is recorded in saturation in a portion corresponding to the video signal width. Next, magnetic tape 3
As the recording head moves, a video signal is recorded in this video signal width area by the video heads 1a and 1b, but the video signal is not recorded because the cue signal is deep recording using the saturation recording current as described above. There is still enough left after that. Also, from the video signal side, since the cueing signal as described above differs greatly from the track angle of the video signal, the azimuth loss effect (θ in FIG. 3 is usually 800 or more) is large and it is hardly affected. Even if there is some influence, it is only for about 0.5 seconds when the cueing signal exists, so the screen noise that occurs on the playback monitor can be sufficiently tolerated. Next, the force set 14 of the magnetic tape 3 having the tape pattern as shown in FIG. ), the magnetic tape 3 runs as shown in FIG.
0 touches.

A detailed enlarged view at this time is shown in FIG. 3a is a magnetic material made of chromium oxide or cobalt-based iron oxide and has a thickness of several microns.

3b is a base material, and the magnetic material is bonded with a binder.

Reference numeral 20 denotes a cue playback head, which is a magnetic head having a gap 9 as shown in FIG.

Here, gap 9 is used to connect other magnetic heads, such as video heads 1a and 1b1, audio signals, and control signal heads 10.
, is larger than the cue signal recording head 5. Generally, the following relationship holds between the gap 9 and the detectable frequency f.

Therefore, since the gap 9 is large, a low frequency signal (20 Hz), which is a cueing signal, can be detected, but a high frequency signal such as a video signal cannot be detected, and the adverse effects of the video signal on the cueing signal are eliminated.

Furthermore, since the cue signal is detected from the back side, the magnetic path formed by the gap 9 of the cue head 20 becomes longer, as shown by the broken line in FIG. 4, and the equivalent gap becomes larger. Furthermore, since the detection is performed from the back side, a cue signal resulting from deep recording can be detected, but normally recorded video signals have the advantage of being attenuated when reproduced from the back side because they are relatively superficially recorded. Also, since the video signal and cue signal have an angle of θ on the pattern, the cue playback head 20, which has a gap perpendicular to the tape running direction, has a large azimuth loss effect and can hardly detect the video signal. There are no advantages.

In particular, since the newly installed cue playback head 20 is not related to the tape loading operation, it is a great advantage to add the cue function without affecting the space on the main deck or the mechanical sequence section. In the above description, the parallel loading method has been taken as an example, but the present invention is not limited to this, and can be widely applied to other magnetic tape devices including the U-type loading method.

As explained above, in this invention, the cueing signal is superimposed on the magnetic surface of the magnetic tape and recorded, and the cueing signal is detected from the surface opposite to the magnetic material surface, so that the video signal and the cuing signal can be sufficiently separated and reproduced. Furthermore, it is possible to obtain an inexpensive and highly reliable magnetic tape device that can be configured by simply adding a new cue playback head without changing the configuration of a conventional magnetic tape device.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the recording and reproducing operation mode of an embodiment of the present invention, FIG. 2 is a block diagram showing the rewind and fast forward operation modes of an embodiment of the present invention, and FIG. 3 is a block diagram showing the magnetic tape pattern. FIG. 4 is a diagram showing the positional relationship between the cue signal reproducing head and the magnetic tape. In the figure, 3 is a magnetic tape, 5 is a head for recording a cue signal, 14 is a power set, and 20 is a head for reproducing a cue signal.

Claims (1)

[Claims] 1. A tape recording position identification signal is further superimposed and recorded on the magnetic surface of a magnetic tape on which video signals and/or audio signals are recorded, and this recording position identification signal is applied to the magnetic tape. A magnetic tape device characterized by detecting from a surface opposite to the magnetic surface of the magnetic tape device. 2. A head for detecting a tape recording position identification signal is installed in a position where a magnetic tape cassette is to be inserted and fixed, and the head is brought into contact with the back surface of the magnetic tape to detect it. magnetic tape device. 3. The magnetic tape device according to claim 1 or 2, wherein the tape recording position identification signal is composed of a low frequency signal.