JPS60140521A - Position adjusting method of magnetic head - Google Patents

Abstract

PURPOSE:To measure precisely and adjust relative positions of a magnetic disc and a magnetic head by exciting magnetic heads with two kinds of frequency signal to write and generate two adjacent magnetic tracks and comparing the levels of two kinds of reproduced frequency signal with each other. CONSTITUTION:Magnetic heads are excited with two different frequencies f1 and f2 on the magnetic disc, and the frequency of the outside head and that of the inside head are denoted as f1 and f2 respectively. The reproduced output is plotted along the ordinate and the extent of movement is plotted along the abscissa; and when magnetic heads to be measured are moved from the outside toward the inside of a track of a curve f1, the curve f1 appears first and falls after passing a maximum point (a), and meanwhile, a curve f2 is raised and falls after passing a maximum point (b). A ratio or a difference between outputs of frequencies f1 and f2 is a certain value at an intersection C between curves f1 and f2. Since output voltages of frequencies f1 and f2 are increased and reduced clearly if frequencies are shifted from the intersection C even somewhat, the position of the intersection C is obtained surely, and thus, track positioning is performed precisely by measurement.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for adjusting the position of a magnetic head, and is particularly applicable to adjusting the relative position of the front head of a double-sided head for a floppy disk, or adjusting the head mounting position of a general disk drive. It is something that makes you

When assembling a magnetic head and incorporating the head into a double-sided magnetic disk drive such as a 70-bit disk, it is necessary to precisely know the relative position of the head's recording or reproducing magnetic track position and the head's carriage. For example, when a double-sided disk head is placed on a floppy disk, the front and back sides are directly in front of each other, like a transformer, and the two sides are exposed, so they usually have to be placed four tracks apart, but adjusting this arrangement is difficult. .

In contrast, in the past, continuous wave recording was performed on a magnetic disc using the usual method, and the relative position was determined by adjusting the position of the disc in the radial direction to maximize the reproduction output of the recording. Ta.

However, this method has several deficiencies as follows. First, since there is little change in the output with respect to change in position at the point of maximum value, the error is large. However, since the reproduction output fluctuates due to unevenness in the eccentric magnetic characteristics of the disk, changes in the state of contact with the head, etc., it becomes increasingly difficult to set the maximum value. Second, when humans operate manually, they go back and forth around the maximum value many times and rely on the detector's six senses, so although it is possible, it takes an hour and is a lot of manual work. Automation is not easy.

Taking these points into consideration, various experiments and prototypes were carried out, and as a result of this invention, each magnetic head is excited with two types of frequency signals on a magnetic disk to write and create two adjacent magnetic tracks. The relative position between the magnetic disc and the magnetic head is precisely measured and adjusted by calculating the ratio or difference in the levels of the two types of frequency signals reproduced by the magnetic head located between these tracks. It is characterized by being moisturized. Now suppose that two different frequencies f, , f2 are respectively used to fully excite the magnetic heads on the magnetic disk.For example, let the outer side be the frequency fi and the inner side be the total frequency f.

When the magnetic head to be measured is moved from the outside to the inner circumference of the track that draws the curve f1 and the magnetic disk is rotated, the reproduction output of the head will be plotted as shown in the figure with respect to the movement of the magnetic head. becomes. In the figure, is the playback output on the vertical axis? By taking the moving distance on the horizontal axis, we can obtain curves f and f2 (track curves based on frequencies f, f, and K), which are created by moving the magnetic head from the outside to the inside. ! Let the maximum points of f, , f, be ia and b.

Next, when the magnetic head to be measured is moved from the outside to the inside of the track of the full curve f, while rotating the magnetic disk completely, the reproduction output of the head will first be curved f1 as shown in the figure.
When it passes through the maximum point a', ift tends to attenuate, but increases along the entire path, and when it passes the maximum point b'lk, it attenuates again. Furthermore, the amplitude becomes somewhat unstable at the maximum value. Here, if there is no extreme difference in the music i fl and ftO values, f, , f will fluctuate at the same time, so f,
If we take the ratio or difference of the outputs of f and 1f at the intersection point C of , f, we can obtain a value of one foot. Also, if you move even a little from the intersection point C, the output voltages of both f, , and f2 will be
Since the output increases and decreases clearly, the ratio or difference between the two outputs changes greatly, and the position of point C can be determined even if the movement direction is one direction.

In this case, output fluctuations due to eccentricity, uneven rotation, etc. can be almost completely eliminated by ratio or differential, since both tracks of the magnetic head excited by the two frequency signals f, f, respectively, are affected almost equally. .

In this way, the EA of the present invention allows for more precise measurement of track positioning. - The wave numbers f, , f are, for example, 100KH2 and 150H2 [6 It is possible to write at frequencies that are not completely different.

[Brief explanation of drawings]

FIG. 2 is a curve diagram showing the relationship between reproduction output and moving distance according to the present invention. The curves f, , and f for each track are generated by two types of reproduction frequency signals caused by the movement of the magnetic head. ':HI?・、、T2゛111→−Transfer force (inside Tato)

Claims (1)

[Claims] (On an 11 m atmospheric disk, two frequency signals are used to fully excite each magnetic head to create two adjacent tracks. A method for adjusting the position of a magnetic head, characterized in that the relative position between the magnetic disk and the magnetic head can be precisely measured and adjusted by determining the ratio or difference between the levels of frequency signals.