JPH0664704B2 - Magnetic recording / reproducing device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a magnetic recording / reproducing apparatus that can be embodied as, for example, an electronic camera for recording a still image or a disk device for recording digital data.

[Prior art]

In a conventional magnetic recording / reproducing apparatus of this type, particularly in a magnetic recording / reproducing apparatus for a small electronic camera, a recording deck and a reproducing deck are usually provided separately. However, if the recording deck and the reproducing deck are separated, the desire to immediately reproduce the recorded image or the like and immediately re-record if there is a problem cannot be satisfied. The same applies to digital data recording. As an improvement of this point to some extent, a magnetic recording / reproducing apparatus incorporating a recording / reproducing circuit was developed and put into practical use, while a recording / reproducing head in which a recording head and a reproducing head are integrated is used. There is. According to this magnetic recording / reproducing apparatus, it is possible to immediately reproduce and re-record digital data after recording, but it is not possible to re-record image information because the erasing head is not incorporated. The main reason why the erasing head is not incorporated in the above device is that in the case of a digital data recording device, there is no need for an erasing head because so-called overwriting is possible, and in a small electronic camera etc. However, the erasing head, which requires a relatively large installation space, is difficult to assemble in space. In an apparatus using a magnetic disk having a diameter of about 2 inches as a recording medium, when an erasing head is provided together with a recording / reproducing head, it is extremely difficult to set the head position so that a good head touch can be obtained for both heads. . Especially when recording at a high recording density with a recording wavelength on the order of 0.5 μm or less, it is necessary to minimize the spacing loss due to the quality of the head touch of each head. Recording with high recording density is difficult because it is difficult to achieve good recording. Further, in the case of image recording, there is a frame recording mode using two tracks, but in this case two erasing heads are required in addition to two recording / reproducing heads, so a total of four heads Must be installed in a limited space on the deck. Therefore, in this case, the difficulty described above becomes more remarkable. Since there are various difficulties in incorporating the erasing head in this way, in the conventional practice, the erasing of image information is carried out collectively by an erasing device provided separately. Therefore, the desire to re-record immediately after the reproduction is not yet satisfied.

By the way, the gap width and track width of the erase head are
The gap width and track width of the recording / reproducing head must be made larger, and there is a concern that crosstalk will increase when the erase head is brought closer to the recording / reproducing head. Further, when a plurality of heads are arranged in a concentrated manner, it is difficult to realize a uniform and good head touch for each head, and it was considered that the erasing head could not be integrated with the recording / reproducing head so far.

〔Purpose〕

The present invention has been made in view of the above points, and an object of the present invention is to provide a magnetic recording / reproducing apparatus of this type in which uniform and good head touch can be obtained for each head.

〔Overview〕

In order to achieve the above object, the magnetic recording / reproducing apparatus of the present invention includes a magnetic head having an erasing gap and a recording / reproducing gap provided in the head body so as to be separated from each other in the longitudinal direction of the track. The central position between the erasing gap and the recording / reproducing gap separated in the longitudinal direction is the rotation center of the applied rotating magnetic disk and the detection center of the sensor for detecting the rotation index provided on the rotating magnetic disk. It is characterized in that the position is set so as to be substantially on the line connecting the lines.

〔Example〕

1 and 2 are a schematic diagram and a head structure diagram showing an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a rotating magnetic disk, which is rotated counterclockwise around a point 0 by a motor (not shown) at a rotation speed of 3600 RPM (in the case of NTSC). Recording tracks T1, T2 ... Are formed concentrically on the recording surface of the magnetic disk 1 by the composite head 2. A PG yoke 4 as an index for detecting the rotational position of the disk 1 is provided at one point on the outer circumference of the hub 3 located at the central portion of the disk 1. On the other hand, a PG coil 5 as pulse detecting means is provided at one point on the rotation locus of the PG yoke 4 on the apparatus body side. this
The PG coil 5 is arranged on the non-recording surface side of the magnetic disk 1, that is, on the side opposite to the composite head 2.
The pulse signal induced by the magnetic flux generated by the PG yoke 4 during rotation is extracted.

By the way, when still image information is recorded on the magnetic disk 1, tracks T1 and T2 are used for field recording.
In this case, still image information of separate fields is recorded, and when performing frame recording, two consecutive tracks are recorded on tracks T1 and T2.
Field still image information is recorded. In either case, the start and end points of recording are the time point when the PG yoke 4 reaches the position shown in FIG. 1, that is, the center point O of the magnetic disk 1 and the PG point.
A line connecting the center of the coil 5 (that is, the detection center of the sensor for detecting the rotation index provided on the magnetic disk) is Y.
-Y 'means that the PG yoke 4 has arrived on the O-Y line. That is, at this time, the composite head 2 is switched by the PS pulse obtained in the PG coil 5. In the case of image recording, considering the NTSC signal, a signal of 262H (horizontal line) is recorded on one track, but the switching point at this time is the leading edge VS1 of the vertical synchronizing signal VS.
It is, for example, only 7H before. Therefore, the leading edge VS1 of the vertical synchronizing signal VS is θ {360 ° × (7/26) from the OY line which is the switching point on the magnetic disk 1.
2)} is recorded at an angle OO ′. As a result, the noise component generated at the switching point is located in the vicinity of the end portion on the screen, and becomes substantially negligible.

FIG. 2 is a plan view showing the structure of the composite head 2 shown in FIG. The composite head 2 is capable of continuously recording or reproducing various information such as image information or digital data on the tracks T1 and T2 without moving the head, and is provided so that the recorded information can be erased at a proper time. .
That is, the composite head 2 has a first track, for example
A first recording / reproducing gap R / W-1 conforming to T1 and an erase gap E1 are provided separately in the track longitudinal direction, and a second recording / reproducing gap R / W-2 conforming to a second track, for example T2. Similarly, the erase gap E2 is provided separately in the longitudinal direction of the track. The composite head 2 has a 2-track recording / reproducing head 2A on the left side of the YY 'line and a 2-track erasing head 2B on the right side of the YY' line, which are provided independently of each other. These can be realized by integrally joining them with the magnetic shield member 2C for crosstalk prevention and fixing them to the head mounting base 2D. In the figure, P is the track pitch, Wa is the recording / reproducing gap width, and Wb is the erase gap width.

In the composite head 2 having the above-described structure, the central position between the erasing gap and the recording / reproducing gap separated in the track longitudinal direction, that is, the head center (in the present embodiment, the joint between the 2A portion and the 2B portion is The recording / reproducing gaps R / W-1, R / W-2, and the erasure are set by attaching the recording / reproducing gaps R / W-1, R / W-2 to the main body of the apparatus so that they are located on the head center. Gap E1, E2 4
The gaps can be set so that the recording surface of the magnetic disk 1 has almost the same head touch. Thus, a single head may be used, and when incorporated in an electronic camera or the like, it can be handled in the same space as the conventional head. Moreover, after erasing with the erasing gaps E1 and E2, recording can be performed with the recording / reproducing gaps R / W-1 and R / W-2. Can be done. That is, according to the composite head 2, recording, reproduction and erasing can be appropriately performed at any time.

〔The invention's effect〕

According to the present invention, it is possible to provide a uniform and good head touch for each head, and thus it is possible to provide a magnetic recording / reproducing apparatus of this kind in which erasing and recording / reproducing operations are extremely stable.

[Brief description of drawings]

1 and 2 are a schematic configuration diagram showing an embodiment of the present invention and a diagram showing a head structure. 1 ... Rotary magnetic disk, 2 ... Composite head, 4 ... PG
Yoke (rotational position detection index), 5 ... PG coil (pulse detection means), T1, T2 ... Track, R / W-1, R / W-
2 ... Recording / playback gap, E1, E2 ... Erase gap.

Claims (1)

[Claims] 1. A magnetic head having an erasing gap and a recording / reproducing gap provided in a head body so as to be spaced apart from each other in the longitudinal direction of a track, and an erasing gap and recording / reproducing separated from the magnetic head in the longitudinal direction. The central position between the gaps is substantially located on the line connecting the rotation center of the applied rotating magnetic disk and the detection center of the sensor for detecting the rotation index provided on the rotating magnetic disk. , A magnetic recording / reproducing apparatus characterized in that the position is set.