JPS6055509A - Magnetic head - Google Patents

Abstract

PURPOSE:To keep a short distance between a head gap and a recording medium and to attain the recording/reproduction with high density, by setting a recording/reproduction head gap opposite to the disk recording surface of a core put into the barrel part at the single side of a double-barrel slider at a position of <=1/4 total length of the slider between the outlet side of the recording medium and the edge of the slider. CONSTITUTION:A 2-sided floppy disk device produces a thin air layer since air flows into the space between a magnetic head and a recording medium while said medium is rotated. In a normal driving mode, the air layer has the fixed thickness over the entire length of the slider. While the thickness of the air layer is increased when the revolving speed of the medium is increased or the pressing load of the medium is reduced. The distance between the slider and the medium is increased at the area near the inlet of the medium when said pressing load is reduced or the revolving speed is increased. This effect is reduced at the outlet side of the medium. In particular, the distance between the slider and the medium is kept small within a range of <=1/4 total slider length measured from the slider edge at the outlet side of the medium like a case where the load is high and a low revolving speed of the medium. Therefore, a head gap is set at this area.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic head used in a double-sided flexible magnetic disk drive.

Flexible magnetic disk (hereinafter referred to as floppy disk)
The device is widely used as an inexpensive and highly reliable external storage device, and the initial single-sided type has become commonplace, with double-sided types becoming more common, and higher recording densities are being promoted. In a dual-type floppy disk device, a floppy disk medium is held between two sliders supported on leaf springs called gimbals, and a core built into the sliders is a magnetic type that records and reproduces signals. head is used.

In magnetic recording, it has been found that the head output signal at a given wavelength is inversely proportional to the head gap and the separation distance between the recording medium. This separation increases the so-called separation loss, which is directly proportional to the separation distance and inversely proportional to the wavelength. Therefore, in order to achieve high recording density, it is necessary to reduce this separation loss, and it is desirable to maintain the head gap and the recording medium as close as possible.

Conventional magnetic heads for double-sided floppy disks use a twin-barrel slider that makes plane contact with the recording medium and stabilizes its posture, as shown in Figure 1 (a) and (b). A twin-barrel slider with a built-in core for signal recording and playback in one body is widely used.In this case, the head gap is located at the center of the entire length of the slider, or at a position off to the entrance side of the medium. The unit of dimensions in Figure 1 is shoes.

However, with a magnetic head at such a gap position, the head gap may be increased when the number of rotations of the floppy disk is increased to increase the signal transfer speed, or when the pressing load of the slider is reduced to reduce wear on the floppy disk. This has the drawback that the separation distance between the media becomes large, and the output signal and recording density decrease due to separation loss.

The purpose of the present invention is to provide a head gap at an optimal position,
It is an object of the present invention to provide a magnetic head that enables high-density recording and reproduction by keeping the separation distance between the head gap and a recording medium small even when the rotational speed is high or the pressing load is low.

The present invention provides a magnetic head in which a flexible magnetic disk is sandwiched between two twin-barrel type sliders and a core built into one body of the twin-barrel slider performs recording and reproduction of signals. The gap is provided at a position within 1/4 of the total length of the slider from the end of the slider on the exit side of the medium. The gist of the present invention will be explained in more detail below.

In the double-sided fJ floppy disk 44, when the medium rotates, air Mi' is drawn between the magnetic head and the hook, creating a thin air layer. Under normal running conditions, the thickness of this air layer is constant over the entire length of the slider, but as the rotational speed is increased or the pressing load is reduced, the thickness of this air layer increases. According to the measurements made by the present inventor, this ratio is greatest at the end of the slider on the side of the inlet of the mucus into which the air flow flows, and conversely, the end of the slider on the side of the outlet of the medium is not affected much. The measurement results are shown in Figure 2. This involves using a transparent slider under a white light source and measuring the separation distance between the slider and the medium using dark colors. #S2 The dashed line in the diagram indicates the load is 3g for pressing, the rotation speed is 30 (lrpm), the dashed line indicates the pressure (-2 is the load 2 (l f, rotation speed 60Orpm), the solid line is the load for pressing is 20f!, and the rotation speed is 30 (The characteristics of lrpm are shown respectively. The pusher reduces the load 11- by 1
1. If the rotation speed is increased, the separation distance near the medium person 1 will increase. However, this effect is small on the media outlet side, and especially in the range within 1/4 of the slider total length from the slider end on the media outlet side, the same small separation distance as during high load and low speed rotation is maintained. It was revealed. Therefore, if a head gap is provided in this portion, a small separation distance can be maintained even when the rotational speed is increased or the pressing load is reduced, enabling high-density recording and reproduction.

Next, embodiments of the present invention will be described in detail.

Comparative Example As a comparative example of the present invention, a magnetic head having the shape and position of the head gap 1 as shown in FIG. 3 was used. The shape of this magnetic head and the position of the head gap 1 are those most widely used as magnetic heads for double-sided floppy disks. Also, the gap length of the core used was 43μ.
It was a seat.

A slider having the same shape as the Example and Comparative Example but with the head cap position changed to the position shown in FIG. 4 was manufactured. The gap length of the cores used was the same (0.43r). In both FIGS. 3 and 4, the upper side of the drawings is the medium inlet side.

Recording and reproducing experiments were conducted using two such magnetic heads with 5 and 25 inch black. The position is 17 inches of the total length of the slider from the end of the floppy disk, but as can be seen from the results shown in Figure 2, it is 25% of the total length of the slider (=
174), similar effects can be obtained.

As is clear from this, the magnetic head of the present invention is capable of high-density recording and reproducing even when rotating at high speed and under low load.

As explained above, the present invention provides a magnetic head in which a flexible magnetic disk is sandwiched between two twin-barrel type sliders, and a core built in the body of one side of the slider records and reproduces signals. By providing the core gap at a position within 1/4 of the total length of the slider from the slider end on the media exit side [1], the slider thrust can be stably increased even when the media rotates at high speed or when the load is small. This has the effect of realizing density recording and reproduction.

[Brief explanation of drawings]

FIGS. 1(a) and 1(b) are external views of a double-sided floppy disk slider. FIG. 2 is a graph showing the relationship between the relative position on the slider measured using a slider made of a transparent material, the helad gap, and the separation distance between media. FIG. 3 is a plan view of a magnetic head of a comparative example. FIG. 4 is a plan view of the magnetic head of the embodiment. FIG. 5 is a graph showing the relationship between recording density and disk rotation speed. FIG. 6 is a graph showing the relationship between recording density and pressing load. In Figures 3 and 4, 1 is the head gap o.
Figure O 2 Figure Population Outlet O 3 Figure 14 Figure 71'5 Figure Example Otoo 200300400500600 Number of revolutions (r
pm) 71-6 Figure pressing is load (9)

Claims (1)

[Claims] In a magnetic head in which a flexible magnetic disk is sandwiched between two twin-barrel type sliders, and a core built into one body of the twin-barrel slider records and reproduces signals, the dinucro 1 of the core is a recording surface. 1. A head characterized in that a recording/reproducing head key opposite to the recording/reproducing head is provided at a position within 4/1 of the total length of the slider from the slider end on the exit side of the medium.