JPS6295709A - Magnetic head and recording/erasure method using it - Google Patents

Abstract

PURPOSE:To attain erasure with a width larger than a recording track width by making the width of a core end opposed to a magnetic head different from each other. CONSTITUTION:The width of the end face of cores 2, 3 opposed via a gap 1 of the magnetic head I is formed in the core 2 narrower than the core 3. In placing the head I selectively to the position of 0 deg. and 180 deg., the core width of the downstream side in effective operation at the relative movement with a magnetic medium being a disc 4 is changed, and when the core 2 applies recording and the core 3 applies the erasure, then the unerased part is prevented by the erasure having a width wider than the recording track width.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a magnetic head and a recording/erasing method using the same, and is applicable to electronic still cameras and magnetic disk recorders for recording photographic images on magnetic disks. This is useful when applied to magnetic recording devices.

<Conventional technology> An electronic still camera converts a subject image into a video signal,
This video signal is recorded on a magnetic recording medium such as a magnetic disk. For this reason, this type of electronic still camera has a built-in magnetic head for recording and erasing video signals on a magnetic recording medium. Although it would be possible to provide separate magnetic heads for recording and erasing, this has the disadvantage that space is required for each magnetic head, which hinders miniaturization of the camera as a portable camera.

To this end, it has been proposed to reduce the built-in space by using one magnetic head to serve both as a recording head and an erasing head. That is, both a recording current and an erasing current are passed through the same magnetic head winding.

<Problems to be Solved by the Invention> However, when such a single dual-purpose head is used, the following new drawbacks arise. In other words, since the same head is used, the recording track width and the erasing track width are the same, but due to deformation or eccentricity of the magnetic recording medium (in the case of magnetic disks) or uneven speed (in the case of magnetic tape), recording This method has a disadvantage in that it erases a position shifted from the track, resulting in unerased areas.

In view of the above-mentioned drawbacks of the prior art, the present invention provides a magnetic head that can perform recording and erasing with a single head and can perform erasing in a width larger than the recording track width, and a recording and erasing method using the same. The purpose is to

<Means for Solving the Problems> The present invention, which achieves the above object, is based on the following knowledge. In other words, the recording track width during magnetic recording and the erase track width during erasing are the widths of the ends of the cores facing each other across the gap of the magnetic head, on the downstream side in the direction of relative movement of the magnetic recording medium. I have come to understand that it is determined by This is called the trailing edge effect. Therefore,
During recording, the relatively narrow end of the core is positioned downstream with respect to the relative moving direction of the magnetic recording medium, while during erasing, the relatively wide core end is positioned downstream with respect to the moving direction. If it is placed on the downstream side, the trailing edge effect will cause the width to be wider than the recording track width.

We came up with the idea that erasing could be done with a wide erasing track width, and conducted the following experiment.

FIG. 1 is a plan view of the magnetic head I used in this experiment, viewed from the gap side. As shown in the figure, the cores 2 and 3 of this magnetic head (2), which face each other across the gap 1, have a width W1. W2 is different. Specifically, the width W
1=16 μm, whereas the width W2=28 μm.

In the experiment, a magnetic disk, which is a magnetic recording medium, was rotated forward and backward, and the same recording current was supplied to the fixed magnetic head I to record magnetization patterns in each case. Figure 2 shows the result of the above experiment during normal rotation, that is, when the narrow core 2 side is used as the trailing edge, and Figure 3 shows the result of the above experiment when rotating in reverse, that is, when the wide core 3 side is used as the trailing edge. These are micrographs showing magnetization patterns at a magnification of 400 times. Referring to both figures, the width W1 of core 2 = 16 μm and the width W2 of core 3 = 28 μm are the track IMTw1.
It can be seen that the magnetization pattern is formed with = 16 μm and track width TW2 = 28 μm. That is, it has been confirmed that erasing can be performed with a track width TW2 wider than the track width TW1 during recording if the core 2 side becomes the trailing edge during recording and the core 3 side becomes the trailing edge during erasing.

Therefore, the present invention provides that the width of one of the cores facing each other across the gap of the magnetic head is narrower than the width of the other core, and that the relative moving direction of the magnetic recording medium with respect to the magnetic head is A signal is recorded on a magnetic recording medium so that the direction is from the wide side to the narrow side, and magnetic recording is performed so that the relative movement direction is from the narrow side to the wide side of the magnetic head. It is characterized in that the signal recorded on the medium is erased.

<Example> Embodiments of the present invention will be described in detail below based on the drawings.

FIG. 4 is an explanatory diagram conceptually showing the state at the time of recording, and FIG. 5 conceptually shows the state at the time of erasing. The magnetic head shown in both figures is the same as that shown in FIG. That is, gap 1
The width W1 of one of the cores 2 facing each other via the core 2 is narrower than the width W2 of the other core 3. During recording, the magnetic disk 4 is rotated from the core 3 side to the core 2 side as shown by arrow A in FIG. 4 to perform recording. Therefore, the recording track width TW1 at this time becomes the width W1 of the core 2.

On the other hand, when erasing data, the magnetic disk 4 is rotated from the core 2 side to the core 3 side as shown by arrow B in FIG. 5 to erase data. Therefore, the erase track width TW2 at this time becomes the width W2 of the core 3, and erasure can be performed with the erase track width TW2 wider than the recording track width TW1. The direction of rotation of the magnetic disk 4 can be easily reversed by changing the direction of rotation of the spindle motor using a switch.

In the above embodiment, the direction of rotation of the magnetic disk 4, which is a magnetic recording medium, is reversed between recording and reproduction, and the magnetic head is fixed; however, in principle, the direction of movement of the magnetic recording medium relative to the magnetic head is during recording. It would be good if it were the opposite between when and when erasing. This means that even if the magnetic recording medium is moved in one direction, the position of the magnetic head relative to it is 18% when recording and when erasing.
It's fine if you change it by 0°.

FIGS. 6 and 7 are diagrams showing the rotating mechanism of the magnetic head (2). As shown in both figures, a magnetic head having a narrow core 2 and a wide core 3 is fixed to a gear 5 so that it can rotate integrally with the gear 5. The center of the fan-shaped gear 6 that meshes with the gear 5 is fixed to the shaft 7, and as the slider 8 moves in the left-right direction, it rotates clockwise and counterclockwise about the shaft 7. There is. Thus, as shown in FIG. 6, the gear 5, that is, the header, is rotated clockwise by the sector gear 6, which rotates counterclockwise as the slider 8 moves rightward in the figure, and its position is held by the stopper 9. On the other hand, as shown in FIG. 7, the slider 8 is rotated counterclockwise by the sector gear 6, which rotates clockwise as the slider 8 moves to the left in the figure, and is rotated 180 degrees from the position shown in FIG. At that point, the position is regulated by the stopper 10. The gear 5 is always pulled toward the fulcrum 12 that supports one end of the spring 11 by the spring 11, and this spring 11 eliminates backlash between the gear 5 and the fan-shaped gear 5 and raises the position of the magnetic head. This is to maintain accuracy.

If a device having such a rotating mechanism for the magnetic head (2) is used, the same effect as in the embodiment described above can be obtained even if the magnetic recording medium is moved in one direction. That is, if the state shown in FIG. 6 is during recording and the state shown in FIG. 7 is during erasing, it is sufficient to move the magnetic recording medium from the cloth to the left in the figure.

<Effects of the Invention> As specifically explained above in conjunction with the embodiments, according to the present invention, recording and erasing can be performed with one magnetic head, and erasing can be performed with an erase track width larger than the recording track width. Therefore, it is possible to perform good erasing without leaving anything unerased.

[Brief explanation of drawings]

FIG. 1 is a plan view showing a magnetic head according to an embodiment of the present invention, and FIGS. 2 and 3 are diagrams showing a case where a magnetic recording medium is rotated forward and backward using the magnetic head shown in FIG. 1, respectively. A microscopic photograph showing a magnetization pattern, FIG. 4 is an explanatory diagram conceptually showing the mode of recording according to this embodiment, and FIG. 5 is an explanatory diagram conceptually showing the mode of erasing. FIG. 6 and FIG. FIG. 2 is a configuration diagram showing a rotating structure of a magnetic head that realizes an embodiment of the present invention. In the drawing, ① is a magnetic head, 1 is a gap, 2.3 is a core, and 4 is a magnetic disk. Procedural amendment (formula February 6, 1986)

Claims (2)

[Claims] (1) The width of one of the cores facing each other through the gap is
A magnetic head characterized by having a width narrower than that of the other core. (2) The width of one of the cores facing each other through the gap is
Signals are recorded on the magnetic recording medium so that the direction of movement of the magnetic recording medium relative to the magnetic head, which is narrower than the width of the other core, is from the wide side to the narrow side of the magnetic head. 1. A recording/erasing method characterized by erasing a signal recorded on a magnetic recording medium such that the moving direction of the magnetic head is from the narrow side to the wide side of the magnetic head.