JPS6080181A - Head positioning device of magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To improve the head positioning accuracy by using a nonvolatile data memory means which stores previously the value for correction of a positioning error between two magnetic heads and using this correction value to control a stepping motor. CONSTITUTION:A stepping motor 1 is revolved at a fixed angle for each fall of STEP. While DIRECTION indicates the revolving direction of the motor 1 with a signal given from a host controller. When this signal has a low level, a magnetic head moves toward the inner tracks of a magnetic disk. Then SIDE selects an upper magnetic head 7 and a lower magnetic head 8 at a low level and a high level respectively with a switching signal for heads 7 and 8.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a head positioning device for a magnetic recording/reproducing device, and in particular, to improving the alignment accuracy of the upper and lower heads of a magnetic head positioning device that uses a stepping motor. The present invention relates to a head positioning device for a magnetic recording/reproducing device.

[Background of the invention]

In a conventional magnetic recording/reproducing device having a removable magnetic disk such as a floppy disk, the positioning error of the magnetic head is required to be below a certain tolerance value in order to maintain compatibility between the devices 6.

This 8'1 capacitance value varies depending on the number of tracks per unit length (track density) and the configuration and dimensions of the magnetic head, but if a tunnel erase type head with guard bands on both sides of the data is used, The value roughly corresponds to the tunnel erase gap width.

Therefore, as track density increases, higher head positioning accuracy is required.

Figure 1 is a diagram widely used in conventional floppy disks.
FIG. 1 is a schematic perspective view of a conventional example of a head positioning device.

In this FIG. 1, 1 is a stepping motor, 2 is a
A pulley press-fitted into the shaft of the stepping motor 1,
3 is a steel belt, 4 is a rail fixed to a floppy disk drive chassis (not shown), 5 is a carriage, 6 is a helad arm, 7 is an upper magnetic head, 8 is a lower magnetic head, 9 is not shown A chucking device for fixing a magnetic recording medium (floppy disk) to a floppy disk drive, IO is a reference track sensor.

The operation of the head positioning device with such a configuration is as follows.
The rotation angle of the stepping motor 1 fixed to the chassis changes in steps according to a control signal. Therefore, the pulley 2 also rotates in a stepwise manner. This rotation of the pulley 2 causes the carriage 5 to move linearly along the rail 4 via the steel belt 3.

That is, the carriage 5 moves linearly in accordance with the rotation of the stepping motor 1 that changes in a stepwise manner. That is, since the stepping motor 1 rotates at regular intervals, the carriage 5 performs linear motion at regular intervals.

The upper part is therefore attached to a carriage 5 and a head arm 6 fixed to the carriage 5.

The lower magnetic head 7.8 performs linear motion at regular intervals.

This spacing is defined as the spacing between tracks (the reciprocal of the track density).
, the upper and lower magnetic heads 7.8 are positioned at the track position.

Then, the reference track position sensor 1o is moved to the carriage 5.
To detect the position of the upper and lower magnetic heads 7.8
This is a way to know when the track has reached the reference track position (usually the outermost track position N).

Positioning error factors in a magnetic recording/reproducing device using such a magnetic head positioning device include (1) angular error of the stepping motor (usually around ±3-3 of the rotation angle), and (2) absolute value accuracy of the pulley diameter. (3) Accuracy in mounting the rail to the shear, (4) Accuracy in chucking the magnetic disk, (5) Expansion and contraction of the magnetic disk due to temperature and humidity, (
6) There is an alignment error between the upper and lower magnetic heads.

In the current magnetic recording/reproducing device using a 3-inch diameter magnetic disk, the total of these is about 80 μm, and due to the limitation of the tunnel erase width mentioned above, 100' rpi () rack/inch = number of tracks per inch. ) to 15
Approximately 0Tkm is the limit of track density, which is an obstacle to increasing the density.

Of these, the alignment error between the two upper and lower magnetic heads in (6) above is about 10 μm in the L1 conventional technology, and in order to achieve high density, this must be reduced to about 3 μm1. There's a problem.

[Purpose of the invention]

An object of the present invention is to provide a head positioning device for a magnetic recording/reproducing device that improves head positioning accuracy and realizes high-density recording in a magnetic head positioning device using a stepping motor. It is.

[Summary of the invention]

The configuration of the head positioning device for a magnetic recording and reproducing device according to the present invention is such that the head positioning device for a magnetic recording and reproducing device positions at least two magnetic heads for recording and reproducing data using a stepping motor. A nonvolatile data storage means is provided in which a value for correcting the positioning error of the two magnetic heads is stored, and the stepping motor is controlled by the correction value stored in the data storage means.

The details are as follows.

That is, the present invention improves the head positioning accuracy by reducing the magnetic head positioning error caused by factor (6) among the positioning error factors mentioned above.

The head positioning error due to this factor is caused by the carriage assembly, that is, the carriage 5 in FIG. It differs depending on the head arm 6, lower magnetic head 7, and lower magnetic head 8, and differs for each magnetic recording 11f pressure device due to cracks.

In the present invention, after the head positioning device is assembled,
The alignment error of the lower magnetic head is measured in advance for each floppy disk drive, the floppy disk drive is equipped with means for correcting the error, the correction value is stored for each floppy disk drive, and the value is used to
By controlling the head position, errors in alignment of the upper and lower magnetic heads are absorbed, and head positioning accuracy is improved.

As a means of position error correction, we have made it possible to easily achieve this by utilizing the fact that the resting position of the stepping motor after a stepwise rotation changes minutely by controlling the stepping motor's internal magnetic field. It is something.

In other words, by the signal that switches the second magnetic head,
The PI'tOM outputs data so that both the upper and lower magnetic heads are sent to the correct track position, and the stepping motor is slightly deflected to correct the alignment error of the upper and lower magnetic heads. It is.

[Embodiments of the invention]

Embodiments according to the present invention will be described with reference to the respective figures.

FIG. 2 is a circuit diagram of a head positioning device for a magnetic recording/reproducing device according to an embodiment of the present invention.

Therefore, the illustrated circuit configuration is newly installed in the stepping motor 1 shown in FIG.

In the figure, 1 is a stepping motor, 11 is a phase counter, 12 is a data storage means (1) I is also an OM (programmable read-only memory), 13 is a converter, 1
4 is a stepping motor driver.

First, to explain the input signal, s'rICpit
,'' is a signal sent from the third controller to move the magnetic head by one track.

In this embodiment, the stepping motor 1 rotates by a certain angle every time 5TEP falls.

DIREC'r'ION is also a signal from a higher-level controller that instructs the rotation direction of the stepping motor 1. When this signal is at a low level, the magnetic head moves toward the inner track of the magnetic disk.

5IDE is a switching signal for the lower magnetic head 7.8.
When the level is low, the lower magnetic head 7 is selected.

Similarly, when the level is high, the lower magnetic head 8 is selected.

Next, the operation of each part will be explained.

The phase counter 11 receives commands from the upper controller and DII (by the ECTION signal) tJP
DOWNL indicates the output rack number.

A 2-bit binary value output Q of this phase counter 11.

, Q, are applied to the Dl terminal of the stepping motor driver 14 through the EOR gate, and the Ql
is similarly applied to the D2 terminal.

Therefore, D+ of the stepping motor drive 14
, D2 terminal, the phase counter 11
When UP, (0,0)→(0,1)-)(1°1)→(
1, 0) → (0, 0) → . . . is repeated.

On the other hand, when the count is down, (0,0)→(i
, o) → (1,1) → (0,1) → (0°O)...
・This is repeated.

This stepping motor driver 14 is, for example, IC, HA 13421P manufactured by Hitachi, Ltd., and FIG. 3 is a rotation principle diagram showing the operating principle of the stepping motor.

Therefore, when the D1 terminal is at a low level, the current corresponding to the input voltage of the input terminal E1 in FIG. current, and when the D1 terminal is at a low level, the Swiss transistor T1. ．．
By turning on T4, the light is flowed in the b direction. The switching transistors T5 to Tp8 perform the same operation for the current corresponding to the input voltage of the input terminal E2.

That is, the voltages applied to the input terminals E1 and Ez are applied to the A-phase and B-phase windings of the stepping motor 1 with their direction controlled by the input signals to the DI and 1)2 terminals.

Therefore, if a commercially available hybrid stepping motor is used as the stepping motor 1, for example,
Phase counter 11 count UP or count])
Due to OWN, the signals of the DI and J)2 terminals change as described above, so the magnetic field inside the stepping motor 1 rotates as shown in FIG. 3, and the stepping motor 1
will rotate. Therefore, the magnetic head moves one track at a time.

Next, correction of positioning errors will be explained.

FIG. 4 is an explanatory diagram of a control method showing actual measured values of minute static position changes when controlling the voltage of the windings of the stepping motor.

In other words, symbol (■) in the same figure shows the rest position of the stepping motor when the voltage ratio applied to the A-phase winding and the B-phase winding is changed. The horizontal axis shows the voltage of the human phase winding and the B phase winding, and the vertical axis shows the rest position.

This shows that by controlling the voltage, the rest position can be controlled by ±1/2 steps from the balanced position when the same voltage is applied.

Therefore, by controlling the voltages of the human-phase winding and the B-phase winding, the magnetic head can be positioned at any desired position.

In the same figure, the duty (
It shows the rest position when changing the duty ratio. This shows that by changing the duty ratio of the A-phase winding and the B-phase winding, the stationary position can be controlled in the same way as when changing the voltage ratio.

Correction of positioning errors is performed as follows.

First, after completing the assembly, write a special signal to measure the positioning error on the calibration disk (disk).
The positioning error is measured by reading this signal with a magnetic head. ), above.

Measure the positional deviation value of the lower magnetic head 7.8. The duty ratio or voltage value of the human phase and B phase corresponding to this positional deviation value is determined from the graph of FIG. 4, and data corresponding to this duty or voltage value is written into the PROM 12.

Therefore, when using the drive, depending on the 5IDE,
The data correcting the positional deviation of the upper and lower magnetic heads 7.8 is output from the PROM 12, and the rotation angle of the stepping motor 1 is corrected by a value corresponding to the data, so that both the upper and lower magnetic heads 7.8 are normalized. is sent to the track position.

Next, specific configuration examples of the converter 13 shown in FIG. 2 will be explained using the circuit diagrams in FIGS. 5 and 6.

First, FIG. 5 shows an example of a configuration using a D/A converter (digital/analog converter).

As mentioned above, 12 is a PROM, 14 is a stepping motor driver, and 17 is a D/A converter.

So, the data written in PROM12 is D.
/A converter 17 into an analog voltage value, and the driver transistor T9 r '], 'IO inputs the stepping motor driver 140 input terminal EI I +
E2 is driven by constant voltage.

Therefore, this is a suitable method for controlling with the voltage shown in FIG. 4 above.

Next, FIG. 6 is a circuit diagram relating to a method of changing the duty in another configuration example.

In the figure, 12 is a FROM, 14 is a stepping motor driver, 15 is an oscillator, 16 is a frequency divider, and 18 is a digital comparator.

That is, the frequency divider 16 always divides the pulse of the oscillator 15 into binary values.

Therefore, a carry occurs every certain pulse, and the flip-flops F'P2 and F'F3't are reset. The digital comparator 18 compares the output value of the ROM 12 and the output value of the frequency divider 16, and if they match,
Flip-flop FF2 or F l”3 respectively
7).

Therefore, a duty signal according to the value of 2110M12 is generated in the flip-flops FF2, F, and F3, and switches the driver transistors To and T12.

Therefore, the stepping motor driver 140 input terminal E l ! Vcc with a duty ratio according to data in the PROM 12 is applied to E2.

This method uses the driver transistor T o + TI2
is a saturated operation, so it is efficient.

In addition to the above, according to the above embodiment, it was possible to improve the accuracy of positioning the upper and lower magnetic heads of the open loop head positioning device using a stepping motor.

That is, the alignment error of the upper and lower magnetic heads has been improved from the conventional 10 μm to 3 μm, and the accuracy has been improved.

Although the above explanation was based on a floppy disk, the present invention is not limited to use only with a floppy disk, but can be widely used in open-loop position control systems using stepping motors. .

In the example of the converter that changes the duty ratio shown in FIG. 6, by operating the input terminals E1 and E2 complementary, the digital controller
t 1 ([i!ilK L, flip-flop]-Jr
It is also possible to exclude 3.

Further, the PROM 12 may be any non-volatile storage means, and it is clear that it may be an ultraviolet erasable ROM, a mask ROM, or a RAM (Random Access Memory) banked up by a battery.

〔Effect of the invention〕

According to the present invention, the accuracy of positioning the upper and lower magnetic heads can be improved with only the electronic components installed in the conventional one without using a new head positioning device.

[Brief explanation of drawings]

Part 3 l Figure 4 ■

Claims (1)

[Scope of Claims] 1. In a head positioning device for a magnetic recording/reproducing device in which two magnetic heads for recording and reproducing data are positioned using at least a stepping motor, a positioning error between the two magnetic heads is determined in advance. 1. A head positioning device for a magnetic recording/reproducing apparatus, characterized in that a non-volatile data storage means is provided in which a value for correcting is stored, and the stepping motor is controlled by the correction value of the data storage means. 2. A head positioning device for a magnetic recording/reproducing device according to claim 1, wherein the stepping motor is controlled by controlling the driving voltage of its winding. 3. Head positioning of a magnetic recording/reproducing device according to claim 1, wherein the stepping motor is controlled by controlling the duty ratio of the driving voltage of the winding. Device.