JP2523799B2 - Magnetic recording / reproducing device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus which is particularly effective for use in video floppies.

2. Description of the Related Art A conventional example will be described with reference to the drawings.

FIG. 3 is a block diagram showing a video floppy device for recording and reproducing a still image on a magnetic sheet. In FIG. 3, the magnetic head 2 contacting the magnetic sheet 1 is moved in parallel in the radial direction of the magnetic sheet 1 by the movement of the carriage 5 that fixes the magnetic head 2 by the rotation of the rotation shaft 4 of the stepping motor 3. Further, the magnetic head 2 has a two-head configuration, one of which is connected to the erasing signal generator 8 and the other of which is connected to the recording / reproducing circuit through the changeover switches 6 and 7, and therefore, the erasing signal generator during erasing. An erasing signal is supplied from 8 to the magnetic head 2.

FIG. 4 is a diagram showing the relative relationship between the recording track of the magnetic sheet 1 and the magnetic head, and the operation during erasure will be described below.

Recording tracks 12a, 12b, 12c are recorded on the magnetic sheet 1 with a track width of 60 μm and a guard band (hatched portion) of 40 μm. The magnetic head 2 has a two-track structure and has the same shape as the recording track 12 in the track width direction. Therefore, the recording track 12 can be erased by supplying an erasing current to the magnetic head 2. Since the recording track 12 has an error due to the dimensional error of the recording device and the temperature characteristic of the magnetic sheet 1, the position of the magnetic head 2 with respect to the recording track 12 is changed to prevent the generation of an unerased portion.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in the conventional apparatus, displacing the magnetic head 2 in the track width direction of the recording track 12 means that erroneous erasing of adjacent tracks occurs, and therefore the displacement amount is limited, As a result, there is a drawback that an unerased portion is generated and interferes with the recording signal.

Means for Solving the Problems The magnetic recording apparatus of the present invention supplies an erasing current to a recording / reproducing head having a two-head structure, and further controls the position of the magnetic head in the track width direction at every 1/3 of a track pitch to transfer the head. It is characterized by comprising means for performing.

According to the present invention, the two-head magnetic head supplies an erasing current to one magnetic head and moves in the track width direction of the magnetic sheet at an interval of 1/3 of the track pitch of the recording track of the magnetic seed. . The magnetic head supplied with the erasing current is displaced by ± m / n with respect to the center of the recording track width to erase in a wider width than the recording track width.
When erasing a frame recording track, the value of m is changed between the inner circumferential direction and the outer circumferential direction of each recording track to erase all between the frame tracks.

Embodiments FIGS. 1 and 2 show an embodiment of the magnetic recording / reproducing apparatus of the present invention. In FIG. 1, a magnetic head 2 that contacts the magnetic sheet 1 is attached to a carriage 5 that moves by rotation of a rotation shaft 4 of a stepping motor 3, and moves in the radial direction of the magnetic sheet 1. Further, the magnetic head 2 has a two-head configuration, one head is connected to the video signal recording / reproducing system, and the other is connected to the changeover switch 11. Similarly, the changeover switch 11 is connected to the video signal recording / reproducing circuit and the erasing signal generator 8. The erasing signal generator 8 supplies an erasing current to one of the magnetic heads 2 by the changeover switch 11 during erasing.

Next, the operation of the magnetic head 2 at the time of erasing will be described with reference to FIG.

FIG. 2 shows the relative positions of the recording tracks 12 recorded on the magnetic sheet 1 and the magnetic head 2. The recording track 12 which is determined as the frame recording by the recording mode detector 10.
Indicates that a video signal of one frame is recorded, 12a represents the first field, and 12b represents the second field.

The magnetic head 2 is rotated by the stepping motor 3 in correspondence with the rotation of the magnetic sheet 1 so that the recording track 12 (60 μm) is rotated.
m) every 1 / n (n = 10 μm), and at the time of erasing, it is displaced by + m / n and −m / n (m is a positive integer) with respect to the track width center.

For example, to erase the recording track 12a, + m = 1,
-M = 3, + 10μm for each track width center,
Displace by -30 μm. Similarly, in order to erase the recording track 12b, setting + m = 3 and −m = 1 gives +30 μm and −10 μm with respect to the track width center. Therefore, the frame recording tracks 12a and 12b are guard bands (hatched areas).
All will be erased, including.

EFFECTS OF THE INVENTION As described above, the magnetic recording / reproducing apparatus of the present invention does not have an unerased portion even if an error occurs in the recording track position due to the compatibility or the temperature characteristic of the magnetic sheet. Since the signal (so-called ID signal) is superimposed, it is possible to prevent erroneous discrimination due to unerased, and it is possible to perform good recording and reproduction.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a magnetic recording / reproducing apparatus of the present invention, FIG. 2 is an explanatory diagram of an erasing operation of the apparatus, FIG. 3 is a block diagram showing a conventional magnetic recording / reproducing apparatus, and FIG. [FIG. 3] is a relational layout diagram of a magnetic head and a magnetic sheet of the same apparatus. 1 ... Magnetic sheet, 2 ... Magnetic head, 3 ... Stepping motor, 4 ... Rotation axis, 5 ... Carriage, 8 ...
Erase signal generator, 10 ... Recording mode detector.

Claims (1)

(57) [Claims] 1. A recording / reproducing head having a field recording mode for recording a video signal of one field unit on each concentric circular track of a magnetic sheet and a frame mode for recording a video signal of one frame on two tracks. A magnetic recording / reproducing apparatus that performs erasing by means of supplying an erasing current to one of the heads and moving the recording track by the same amount both in the inner and outer peripheral directions when erasing the field recording track to make it wider than the recording track. A magnetic recording / reproducing apparatus characterized by comprising head position control means for changing the head movement amount from the center of each recording track in the inner circumference and in the outer circumference when erasing a frame recording track.