JPS61287011A - Rotary head type recorder - Google Patents

Abstract

PURPOSE:To attain the best recording at a running speed even when the speed is any speed by moving a rotary erasure head in the direction crossing its turning face so as to control the track width recorded by a rotary recording head. CONSTITUTION:Recording and reproducing rotary heads HA-HD are fitted on a rotary drum S with a phase difference of 90 deg.. Electromechanical converting elements (e.g., bimorph piezoelectric elements) B1, B2 move erasrue heads E1, E2 at a right angle to the turning face. When an operation section 9 indicates a tape speed, a mode desiguation circuit 10 applies a mode desiguation signal to a bimorph drive circuit 13 to decide the drive level of the converting elements B1, B2. Further, a capstan control circuit 14 decides the tape running speed. Thus, the recording with the best recording track width is attained at any tape running speed.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a rotary head type recording device, and particularly to a rotary head type recording device including a rotary erasing head and a rotary recording head.

Summary of the Disclosure> The present specification and drawings describe a rotary head type recording device in which a rotary erasing head is displaced in a direction intersecting the rotating surface thereof;
By controlling the track width recorded by the rotating recording head, the best recording is possible at any speed of the recording medium traveling in the direction intersecting the rotating head. This paper discloses a technique for providing a rotary head type recording device that can perform the following functions.

<Prior art> In this type of device, as a process toward high-density recording,
A device has been realized that can change the track pitch by changing the traveling speed of a recording medium when it is traveling in a direction intersecting the rotational direction of a rotary recording head.

For example, there is a model of home video tape recorder that is capable of recording on the same cassette tape for a long time. This is the standard tape speed recording/playback mode (S
P) and a long-time recording/playback mode (LP) at a tape speed of l/n (n>1),
SP when users need high-quality playback images
.

It was extremely easy to use, as it could be used as an LP if running costs were to be given priority over image quality.

<Problems to be Solved by the Invention> However, in recent years, there has been a trend toward multiheads in the field of VTRs, and it is difficult to install special playback heads for so-called slow-motion playback, still playback, etc., SP, LP dedicated heads, etc. , it becomes necessary to provide a large number of heads on one rotating cylinder. This causes a number of problems such as problems with mounting accuracy during assembly, problems with crosstalk between rotary heads, and instability in tape running.

Moreover, on the other hand, 180 mm of tape is conventionally placed on a rotating cylinder.
For VTRs, which record and play back data using two heads that rotate over an angular range of 180° or more, the tape is wound over an angular range of 270° or more in order to downsize the cylinder. A VTR that performs recording and playback by sequentially using four heads that are wound around each other and rotated with a 90° phase difference.
The proposal has also been implemented.

In such a VTR, it is no longer possible to have dedicated recording and reproducing heads for LP and SP respectively. Therefore, it is conceivable to make the head width of the recording/reproducing head correspond to the track pitch of the LP or to the track pitch of the SP. However, if the head width is adjusted to the track pitch of the LP, the image quality in the SP will be insufficient and a guard band will occur, making it impossible to perform so-called four-frequency tracking control. On the other hand, if the head width is adjusted to the SP track pitch, the overwritten portion will increase abnormally, resulting in a significant deterioration of the LP image quality.

The present invention has been made in view of the problems typified above.

To provide a rotary head type recording device capable of performing the best recording at any traveling speed of a recording medium traveling in a direction intersecting the rotary head.

Means for Solving the Problems> In order to solve the above-mentioned problems, the present invention displaces the rotating erasing head in a direction intersecting the rotating surface of the disk to control the track width recorded by the rotating recording head. It was configured to do so.

Effects> With the above-described configuration, the track width can be freely controlled by immediately erasing a portion of the track recorded by the rotary recording head.

<Example> Hereinafter, the present invention will be described in which 27 tapes are attached to a cylinder in a 4-head configuration.
This will be explained using an implementation applied to a vteR that is wound over 0°.

□FIGS. 1(A) and 1(B) are diagrams showing the head configuration of a VTR according to an embodiment of the present invention.

1(at)Ice)to are rotary heads for recording and reproducing, respectively, and IIEI-B2, which are mounted on the one-rotation drum S with a phase difference of 90°, are rotary erasing heads, B
1 and B2 are electro-mechanical conversion elements (for example, bimorph piezoelectric elements) for moving the erasing head E11E2 perpendicularly to the rotating surface.

It is assumed that erasing head E1 rotates with a phase intermediate between heads H8 and heads Hc, and erasing head E2 rotates with a phase intermediate between heads H^ and heads Ho.

For the head width of each head, first read/write head H.
^, HB, Hc, H, are each sp's trough h-1 4 I-Ll+To/Echushojisu To Nado 1 so VE l
, E2, the recording/reproducing head H^, HB, Hc
.

It is actually larger than Ho.

During recording in SP, the erasing head E I t
E2 is set at the same height so that it traces on the tape in advance before the recording/reproducing head traces, so that an erase signal is always sent.

At this time, it is necessary to raise the lower end of the erasing head by 1.5 TP (at SP) or more than the lower end CP of the recording/reproducing head shown in FIG. 1(B). In SP, even with this configuration, good recording and reproduction can be performed.

FIGS. 2(A), CB), (C), and CD) are diagrams showing the state of recording on an LP. Figure 2 (A) shows the head H^
As shown in Figure 0, which shows the state of recording in the recording process, approximately half of the recording tracks of the head HA are immediately erased by the erasing head E2 which traces the tape immediately after the head H^. At this time, the conversion element B2 is controlled so that it is shifted upward by a slightly larger amount than the erasure spacing (in LP). Figure 2 below (B
).

(C) and CD) are respectively heads HB * Hc * HD
The recording state is shown by the erasing head E2e.
Approximately 1/2 of the recorded track is erased immediately after recording due to E l + E 1, and the shift amount of the erase head at this time with respect to P in FIG. 1(B) is 1/2 TP,
It is assumed that 5/6TP and 1/2TP (in LP) are slightly larger.

FIG. 3 is a timing chart showing the operation timing of each head. In FIG. 3, PG is a rectangular wave signal having one period per revolution of the drum S. Also H^, HB.

Hc, HD is head Ha*He-Hc*
Signal tE1e indicating Ho operation timing at high level
E2 is a signal indicating the operation timing of the erasing head E I * E 2 at a high level, and B 1 * B 2 represents an example of the drive voltage of the conversion element B I * B 2.

FIG. 4 is a block diagram showing a schematic configuration of the VTR of this embodiment. The video signal input from terminal 1 is converted into a signal form suitable for recording by video signal processing circuit 3, and then sent to heads H^ and H via switches 4A and 4e*4c*4o.
The signals recorded by the heads B, Hc, and HD, and conversely reproduced from the heads H^, HB, Hc, and HD, are output from the terminal 2 in the video signal processing circuit 3 in their original signal form. Become.

The PG obtained by the drum rotation detector 5 is sent to the recording head drive circuit 6.
and the aforementioned switch 4A-4B+4c,
4. The signal H shown in FIG. 3 above controls the signal H^.

H8, Hc * Generates HD.

On the other hand, this PG is also supplied to the erase head drive circuit 8, which generates the signal E I e E 2 shown in FIG. 3 and controls the switches 11, 12. When the switches 11 and 12 are turned on, the erase signal output from the erase signal generating circuit 7 is supplied to the erase head E I + E 2. The output signal of the drive circuit 8 is also supplied to the bimorph drive circuit 13, and the LP
At times, the above-mentioned conversion element drive signals B, , B2 are output.

The user instructs the tape speed of LP, SP or other tape speeds using the operation unit 9. Accordingly, the mode designation circuit 10 supplies a mode designation signal to the bimorph drive circuit 13, and determines the drive level of the conversion elements B1 and B2. The capstan control circuit 14 also determines the tape running speed.

By configuring as described above, recording can be performed with the best recording track width at any tape running speed, and the best image quality can be obtained at each tape running speed.

In the above embodiment, the explanation was given by taking as an example a VTR that sequentially uses four heads rotating with a phase difference of 90' as a recording head, but the present invention is applicable to a conventional two-head helical force scan type VTR. It is also possible to apply the invention. In this case, especially when three or more track pitches are set, three or more positions of the erasing head in the rotation axis direction are set.
It is extremely advantageous to control it.

Furthermore, it is of course possible to accommodate other arrangements of recording heads as appropriate.

<Effects of the Invention> As explained above, according to the present invention, the best recording can be performed at any speed of the recording medium traveling in the direction intersecting the rotating head. A rotary head type recording device is obtained.

[Brief explanation of drawings]

FIG. 1 (A), CB) shows a VT as an embodiment of the present invention.
Diagrams for explaining the head arrangement of R, Fig. 2 (A), (
B), (C), and CD) are diagrams showing the state of recording by the head shown in Fig. 1, Fig. 3 is a timing chart showing the operation timing of the head shown in Fig. 1, and Fig. 4 is the same as Fig. 1. 1 is a diagram illustrating an overall schematic configuration of a VTR equipped with a head shown in FIG. HA, Ha * Hc, Ho is the recording head, E 1
*E 2 is an erase head, B l + B 2 is an electromechanical transducer, and 13 is a bimorph drive circuit. Figure 1 (B) No. Zi (C) %2i (D) No. 30

Claims (1)

[Claims] A rotary head type recording device comprising a rotary recording head and a rotary erasing head, the rotary erasing head being moved in a direction intersecting the rotating surface of the rotary erasing head to control the track width recorded by the recording head.