JPS63304402A - Magnetic recording reproducing system - Google Patents

Abstract

PURPOSE:To obtain the high position accuracy of head mechanism by recording a different signal to the depth and the surface layer of a magnetic layer and erasing only the region of the depth other than the signal recorded therein before a signal is recorded thereto. CONSTITUTION:An erasure gap 3 is arranged to a preceding position to the direction of rotation 4 of a recording medium to record a new data by a recording and reproducing gap 2 in this head after an old data recorded on the recording medium is erased sufficiently by an erasure gap 3. In this case, when the recorded medium 16 is reproduced by the head chip, f1, f2 of a servo signal 11 and a data signal are reproduced at the same time and the position of the head mechanism is controlled minutely by an actuator. Through the constitution above, since a servo signal is recorded to the depth and a data signal is recorded on the surface layer, high position accuracy of the head mechanism is obtained by using a recording medium by a conventional manufacture process.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a servo signal recording method for a floppy disk drive device that controls the position of a head mechanism using a position control servo signal recorded on a recording medium. In particular, the present invention relates to a magnetic recording and reproducing method suitable for performing high-precision position control using a general recording medium using the servo signal.

[Background of the invention]

Conventionally, various methods have been proposed and implemented for recording servo signals for position control, but the media magnetic layer proposed in Japanese Patent Publication No. 40-23745 because of its high tolerance for position control accuracy signal recording accuracy. The optimal method is to record servo signals deep within the core.

However, in this known example, the medium magnetic layer needs to have a three-layer structure including an intermediate non-magnetic layer, which poses problems such as the productivity of the medium and the difficulty of recording due to the high coercive force of the lower layer. was.

[Purpose of the invention]

An object of the present invention is to record a position control servo signal in the deep layer of a recording medium having a single or multiple magnetic layers, and to record data on the surface layer of the recording medium at regular intervals without passing through a non-magnetic material. The object of the present invention is to provide a magnetic recording and reproducing method capable of recording signals.

[Summary of the invention]

In the present invention, the position control servo signal has a low signal frequency and can be recorded over the entire depth direction of the magnetic layer of the recording medium, and the data signal has a high signal frequency and can be recorded on the recording medium due to the recording demagnetization effect. Taking advantage of the fact that the magnetic layer can record only up to a certain depth, the recording depth is controlled by separating the position control servo signal recording gap and the data signal recording gap, and the position control servo signal By using the recording gap as the erasing gap or recording gap that has been provided conventionally, the above-mentioned objective can be achieved without making any major changes to the head structure.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view of the surface of a head chip 1 that is in contact with a recording medium, and FIG. 2 is a cross-sectional view taken along the line AA. In order to record new data in the recording/reproducing gap 2 after sufficiently erasing the conventional data recorded on the recording medium using the erasing gap 3, this head moves ahead in the rotational direction 4 of the recording medium. The erasing gap 3 is provided at the position. This erasing gap 3 is used as a recording head when erasing conventional data and at the same time recording position control servo signals 11 (hereinafter referred to as servo signals). (See Figure 3) A magnetic layer 10 (third layer) with a thickness of 2 μm is placed on top
Since it is necessary to magnetize the deep layer of the magnetic layer 10 of the recording medium coated with (see figure), the erase gap length 8 is 4
It is set to μm. Further, the coil 6 for generating magnetic flux in the erase gap 3 is also formed of a pair of coils whose winding directions are opposite when viewed from the common line 35. Further, a data signal recording/reproducing gap 2 is provided behind the erasing gap 3.

In this embodiment, the recording/reproducing gap 2 has a gap length 7 of 0.0 mm in order to reproduce data recorded in the circumferential direction of the recording medium at a linear recording density of 35 bits/inch. Although it is set to 35 μm, in order to prevent the magnetic flux saturation of the ferrite core 14 during recording, the recording/reproducing gap 2 is formed by depositing an amorphous film 15 with a high magnetic flux density on the surface of the ferrite core 14. ing. In this example, a recording medium with a coercive force of 1600 (Oe) is used, and a gap length of 0.35 μm is used.
The depth that can be recorded at a density of bits/inch is calculated to be 0.
．． It is about 3 μm. Naturally, the recording/reproducing coil 5 is formed of a pair of coils whose winding directions are opposite when viewed from the common line. Recording and reproducing operations by the head chip 1 configured as described above will be explained with reference to the drawings. FIG. 3 is a diagram explaining the operating principle from servo signal recording to data signal recording, and FIG. 4 is a circuit block diagram during recording. In the head chip 1 having the above-described configuration, the servo signal 11 is sent to the recording medium 16 on which nothing is recorded.
When recording, the servo signal recording circuit 30 is driven according to servo data from the system side, and the windings 22 and 23 of the erasing coil 6 are driven according to the frequency of the servo signal.
A current flows alternately, and a magnetic field 17 generated in the erase gap 3 thereby magnetizes the entire depth direction of the magnetic layer 10 of the recording medium 16. Therefore, the magnetic layer 10 of the recording branch 16
The servo signal 11 will be recorded throughout the depth direction.

Two types of frequencies are used for the servo signal 11, each of which is ft (Hz).

f, zCHz), fl and fz are recorded alternately and concentrically on the recording medium 16 by the above-described operation.

Since the frequency of flfz is reproduced at the same time as the data signal, a frequency of at least 173 to 1/4 of the data signal frequency is selected in order to facilitate separation of each by a filter circuit, and at the same time, harmonics of the servo signal The frequencies are selected such that the components do not interfere with the data signal frequency. Here, the boundary between fl and fz becomes the center of the recording track of the data signal. After servo signals are recorded on all tracks on the recording medium, switch elements 24 and 25 are turned off by an erase signal from the system side, and at the same time, switch element 26 is turned ON and only one winding 23 of the erase coil is turned off.
Connected to 7. When an erasing operation is performed in this state, approximately 1/2 of the servo signal 11 recorded on the recording medium 16 on the surface side is erased by direct current. This operation is performed for all tracks on which the previous servo signals have been recorded. After the above operations are completed, data signals are recorded. At this time, the switch element 26 is turned off, and the switch element 28 is turned on, so that the winding 11A23 is connected to the data signal erasing resistor 29, and a data signal erasing current flows. In this state, while erasing the data area using the erasing head 3, a new data signal 21 is generated using the data signal recording/reproducing gap 2.
is recorded.

Here, as mentioned above, the data signal is recorded up to about 0.3 μm in the depth direction of the recording medium, and the erasing current is also set to a current value sufficient to erase the data. There is. Therefore, the servo signal 11 recorded in the deep layer will not be erased, and since the DC erasing section 12 when erasing the servo signal completely separates the data signal recording section and the servo signal recording section, the data signal The servo signal 11 is not affected by recording. Note that once a servo signal has been recorded, there is no need to record it again, so during normal data signal recording, only the aforementioned data signal recording operation is performed. The same applies if a medium is purchased and used on which servo signals have already been recorded. FIG. 5 is a plan view of the recording surface of the recording medium after performing the above operations, and FIG.
The figure is a BB cross section in FIG. 5. In the deep servo signal 11, the frequencies of fl and fz are alternately recorded as described above, and the boundary between them becomes the center of the data signal 21, that is, the center of the data signal recording track.

As described above, when the recorded recording medium 16 is reproduced by the head chip 1 described above, the ! of the servo signal 11! > ,fz
and data signals are simultaneously reproduced and separated into a servo signal and a data signal by a separation filter, and the servo signal is further separated into fl and fz, and then A/D converted and f
Depending on the reproduction voltage ratio of lfz, the position of the head mechanism (not shown) on which the Herad chip 1 is mounted is adjusted minutely by an actuator (not shown) so that the reproduction voltage ratio of fl and fz becomes the same. controlled. The data signal is converted into digital data by the demodulation circuit and sent to the system side. According to the above configuration, the following effects can be obtained. In other words, it is possible to record servo signals in the deep layer and data signals in the surface layer on a single magnetic layer recording medium.
Recording media can be easily produced, and servo signals can be recorded deep enough. Also, depending on the signal from the system side, the erase gap is used for recording servo signals.

Since it can be switched for servo signal erasure and data signal erasure, the end user of the system can record the servo signal if necessary. Since servo signals are recorded over the entire circumference of one track, the positioning accuracy of the head mechanism during playback is greatly improved. In this embodiment, only one side of the recording medium has been explained, but the above-mentioned operation is performed by a pair of head mechanisms arranged on both sides of the recording medium, and servo signals and data are sent to both sides of the recording medium. The signal is recorded. Furthermore, the structure of the head chip, the value of the gap length, the recording density on the recording medium, etc. shown in this example are just examples, and even if they are changed, the above-mentioned effects will not change in any way. do not have. Further, in this embodiment, a single magnetic layer medium is used as the magnetic medium, but two magnetic layers made of the same material with different coercive forces may be used without interposing a nonmagnetic material. In this case, by appropriately selecting the coercive force ratio between the lower layer and the upper layer, it is possible to more easily separate the servo signal and the data signal during recording. Further, as shown in FIG. 7, the upper layer and the lower layer are made of different magnetic materials, for example, the upper layer is made of barinium ferrite 33. The above-mentioned effect can also be achieved by using the metal 34 with a coercive force of 1600 (Oe) as the lower layer. Of course, there is no need to use a nonmagnetic material between the two layers.

In this embodiment, the erase gap of the preceding erase head is used as the head gap for servo recording, but a head with a wide gap length is used for recording servo signals in the deep layer, and a narrow gap is used for recording data signals in the surface layer. Since the above-mentioned effect can be achieved by using a head with a long length, it is also possible to use a dedicated head for each.

Particularly, when recording servo signals at a media manufacturer or a disk drive device manufacturer, productivity can be increased by using a head dedicated to recording servo signals.

Furthermore, in this embodiment, an example was described using a lead-erase type head having a leading erase gap, but a leading read-only head gap and a rear recording/erasing head gap, that is, an override type head gap, are used. Considering the head chip provided, the rear recording/erasing head gap length can be made sufficiently wider than the preceding read-only gap length, so the above-mentioned servo signal recording is performed in the main head gap. It is possible to do this, and in this case as well, there is no change in the effect described above. Furthermore, in this case, the amorphous portion deposited in the recording/reproducing head gap portion can be omitted, which has the effect of making the head chip less expensive.

〔Effect of the invention〕

According to the present invention, it is possible to record a servo signal in the deep layer of the recording medium and a data signal in the surface layer without using a non-magnetic layer. This has the effect of realizing a magnetic recording and reproducing method that can obtain high positional accuracy.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a head chip according to an embodiment of the present invention, FIG. 2 is a sectional view taken along line A-A in FIG. 1, FIG. 3 is an explanatory diagram of the operation of an embodiment of the present invention, and FIG. Block diagram of recording circuit, 5th
The figure is a plan view of a medium recorded according to an embodiment of the present invention;
FIG. 6 is a sectional view taken along the line BB in FIG. 5, and FIG. 7 is a sectional view of a medium composed of different magnetic layers. Top head chip, 3. Erasing gap, 6. Erasing coil, 10... Magnetic layer, 11... Servo signal, 12
. . . DC eraser, 16 . . . Recording medium, 21 . . . Data signal, 30 . . . Servo recording circuit, 33 . Continuing from page 4 of Figure 3 on the East 3 Inventor: Tetsuo Shinagawa Yokohama City, Kanagawa Prefecture: Disaster discovered within the Home Appliance Research Institute

Claims (1)

[Claims] 1. In a medium having one or more magnetic layers continuous in the thickness direction of the medium, different signals are recorded in the deep layer and the surface layer of the magnetic layer, and the signal in the deep layer is A magnetic recording and reproducing method characterized in that only the area other than the recorded part is erased before recording the signal. 2. In the magnetic recording and reproducing method described in claim 1, the head gap length used when recording in the deep layer and the head gap length used when recording on the surface layer, the former being different from the latter. A magnetic recording and reproducing method characterized by a wide area. 3. In the magnetic recording and reproducing method described in claim 1, a recording and reproducing gap is provided in the same head chip;
An erasing gap having a width wider than the recording/reproducing gap width is provided at a position preceding the recording/reproducing gap in the rotational direction of the recording medium, and a common line is provided in the core portion forming the erasing gap. A magnetic recording and reproducing system characterized by using a floppy disk drive device having a head mechanism equipped with a head chip having two sets of coils arranged in opposite winding directions. 4. The magnetic recording and reproducing method as described in claim 3, wherein the signal in the deep layer is recorded on the recording medium using the erasing gap. 5. In the magnetic recording and reproducing system described in claim 1, the signal to be recorded in the surface layer portion is recorded by a head gap disposed at a position preceding the rotational direction of the medium, and the signal is recorded in the deep layer portion. The signal to be recorded on the medium is recorded by a head gap disposed behind the head gap in the rotational direction of the medium, and the signal recording head gap length for recording on the deep layer is determined by the signal recording head for recording on the surface layer. A magnetic recording and reproducing method characterized by using a head mechanism equipped with a head chip that is widened relative to the gap length.