JP2529231Y2 - Magnetic disk drive - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk drive, and more particularly to a magnetic disk drive having an erase head for forming guard bands on both sides of a recording track and capable of recording data on both sides of the disk.

[0002]

2. Description of the Related Art A floppy disk drive (FD)
In D), in order to guarantee data compatibility, guard bands 2 having a width (about 0.2 mm) smaller than the track width (about 0.33 mm) of the recording track are provided on both sides of the recording track 1 as shown in FIG. Have been.

In order to form the recording track 1 so as to have the guard bands 2 on both sides as described above, the FDD uses a head having an erase head on both sides of a recording / reproducing head.

In order to improve the recording density, the FDD is provided with magnetic heads 4 and 5 on both sides of the disk 3, as shown in FIG. 4, so that data can be recorded on both sides of the disk 3. is there.

FIG. 5 shows a plan view of a magnetic head used in an FDD capable of performing such double-sided recording. In the figure, 4
Reference numerals a and 5a denote ceramic sliders, and read / write (R / W) gaps 4 are provided on the ceramic sliders 4a and 5a.
R / W cores 4c and 5c formed with b and 5b and erase cores 4e formed with erase gaps 4d and 5d, respectively.
5e is embedded. Erase cores 4e and 5e are R / W
The recording tracks 1 are disposed on the left and right sides of the cores 4c and 5c.
Guard bands 2 are formed on both sides.

When recording is performed using such a magnetic head, even if a head misalignment (off-track) occurs as shown in FIG. 6, a recording track newly recorded by the R / W gap 4 is used. Since guard bands 2 'are formed on both sides of 1' by the erase gap 7,
The interval between the recording tracks 1 and 1 'can be reliably guaranteed.

FIG. 7 is a circuit diagram of a conventional erase head drive circuit. In the figure, L ₁ and L ₂ are erase core 4
e and 5e show coils for applying a magnetic field to the erase gaps 4d and 5d.

Reference numeral 6 denotes an erase head drive circuit, which includes current limiting resistors R ₁ and R ₂ and an NPN transistor Q.
_1, consisting of Q _2.

[0009] coil L ₂ are both one end connected to the DC power source Vcc. The other end of the coil L ₁ is connected to the collector of the transistor Q ₁ via the resistor R _1, is connected the other end of the coil L ₂ via a resistor R ₂ to the collector of the transistor Q _2.

The emitters of the transistors Q ₁ and Q ₂ are grounded, and the base is connected to the erase head switching circuit 7.

The erase head switching circuit 7 includes an inverter circuit 7a and AND gate circuits 7b and 7c.

[0012] the base of the transistor Q ₁ is inputted an output signal from the AND gate circuit 7b is, the base of the transistor Q ₂ is the output signal of the AND gate circuit 7c is inputted.

[0013] Two inputs of the AND gate circuit 7b is respectively connected to the terminals T ₁ and T _2, one input of the AND gate circuit 7c is connected to the terminal T _1, the other input via an inverter circuit 7a terminal It is connected to the T _2.

A drive control signal is supplied to the terminals T ₁ and T ₂ from the erase head drive control circuit 18, respectively.

For example, when it is desired to perform recording with the magnetic head 4, if the terminals T ₁ and T ₂ are both at a high level, A
Output a high level of ND gate circuit 7b, the output of the AND gate circuit 7c becomes low level, the transistor Q ₁ is turned on and the transistor Q ₂ is turned off.

[0016] Accordingly, current flows through the coil L ₁ for driving the erase gap 4d of the magnetic head 4 to be subjected to recording.

Further, the high level of the terminal T ₁ if you want to perform a recording magnetic head 5, the output of the AND gate circuit 7b when the terminal T ₂ to the low level a low level, AN
The output of the D gate circuit 7c becomes high level, the transistor Q ₁ is off, the transistor Q ₂ is turned on,
Erase gap 5d of magnetic head 5 to be recorded
Current flows through the coil L ₂ for driving.

As described above, conventionally, the erase gap 4 of the magnetic head 4 or 5 on both surfaces of the disk 3 to be written is
The erase head drive circuit 6 has been configured so that only d or 5d is operated.

[0019]

However, in this type of conventional magnetic disk drive, the erasing heads of the upper and lower magnetic heads are separately driven, so that a switching element is required for each erasing head. There is a problem that a drive switching circuit for switching the two switching elements depending on the case is required, and a plurality of circuits are required.

The present invention has been made in view of the above points, and has as its object to provide a magnetic disk drive capable of driving an erase head with a simple circuit.

[0021]

According to the present invention, there is provided a magnetic disk drive having a structure in which erase heads are formed on both sides of a recording / reproducing head on both sides of a disk. An erase head drive circuit for simultaneously driving the erase head of the magnetic head is provided.

[0022]

The erase head drive circuit may be configured to simultaneously drive the erase heads formed on the magnetic heads arranged on both sides of the disk, and the control signal and the drive circuit can be shared. Things.

[0023]

FIG. 1 is a circuit diagram showing a first embodiment of the present invention. The same components as those in FIGS. 3 to 7 are denoted by the same reference numerals, and description thereof will be omitted. In the figure, reference numeral 9 denotes a drive circuit. Driving circuit 9 consists of transistors Q ₃ and the current control resistor R _3, R _4.

The base of NPN transistor Q ₃ is connected to erase head drive control circuit 10. The emitter of the NPN transistor Q ₃ is grounded, and the collector, the resistance R
₃ and through the coil L ₂ which drives the resistor R ₄ and erase gap 5d is connected to a DC power source through the coil L ₁ for driving the erase gap 4d DC power source V
Connected to cc.

The erase head drive control circuit 10 has a drive control in which one of the magnetic heads 4 and 5 goes high when data is written, and goes low when both the magnetic heads 4 and 5 are in a data read state. It supplies a signal to the base of the NPN transistor Q _3.

[0026] Therefore, when at least either one of the magnetic head 4 or 4 writes, drive control signal becomes high level, the transistor Q ₃ is turned on, a predetermined current to the coil L ₁ and L ₂ flow The erase gaps 4d and 5d are driven together, and a guard band 2 'is formed on the disk according to the position of the magnetic heads 4 and 5.

At this time, the guard band 2 ′ is recorded at a fixed width on both sides of the recording track 1 ′ on the side of the recording head 1, for example, and is recorded between the recorded tracks 1 on the other magnetic head 5. A guard band 2 'having a constant width is formed.

Therefore, if an off-track occurs in either case, the guard band is applied to the recorded track 1 and the track width of the recorded track 1 is slightly reduced. However, since the track width is set to a sufficiently large width, there is no problem in reproduction even if the track width is reduced if the normal off-track amount is used. 3.5 inch 135 TPI FDD has a recording track width of about 60μ
m (off-track ± 30 μm) or more causes no problem in reproduction.

As described above, the erase gap drive control circuit 10 and the drive circuit 9 provide the erase gaps 4d and 5d.
Since both can be shared, the circuit configurations of the erase gap drive control circuit 10 and the drive circuit 9 can be simplified.

FIG. 2 is a circuit diagram of a second embodiment of the present invention. The same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

This embodiment differs from the first embodiment in that the current limiting resistors R ₃ and R ₄ provided in the coils L ₁ and L ₂ of the erase gaps 4 d and 5 d are replaced with a common resistor R _5. Thus, the circuit configuration can be further simplified than that of the first embodiment. However, in the case of the present embodiment, it is limited to the case where the magnetic properties of the erase gap 4d and the erase gap 5d are well balanced.

[0032]

As described above, according to the present invention, since one erase head drive circuit drives a plurality of erase heads, only one erase head drive circuit is required and one drive control signal is provided. Therefore, the circuit has a feature that a circuit related to the erase gap can be simplified.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram of a first embodiment of the present invention.

FIG. 2 is a circuit configuration diagram of a second embodiment of the present invention.

FIG. 3 is a track configuration diagram of an FDD.

FIG. 4 is a diagram illustrating a configuration of a double-sided recording type FDD.

FIG. 5 is a plan view of an FDD magnetic head.

FIG. 6 is a track configuration diagram when the FDD is off-track.

FIG. 7 is a circuit configuration diagram of a conventional erase head drive circuit.

[Explanation of symbols]

1,1 'recording track 2, 2' guard band 3 disks 4,5 magnetic head 4b, 5b R / W gap 4d, 5d erase gap L _1, L ₂ coil 9 driving circuit 10 erase head drive control circuit

Continuing on the front page (72) Inventor Jiro Ueki 3-7-3 Nakamachi, Musashino City, Tokyo TEAC Corporation (72) Inventor Fumio Nagase 3-7-3 Nakamachi, Musashino City, Tokyo TEAC Corporation (56) References JP-A-2-79202 (JP, A)

Claims (1)

(57) [Scope of request for utility model registration] 1. A magnetic disk drive having a structure in which magnetic heads having erase heads formed on both sides of a recording / reproducing head are arranged on both sides of a disk, wherein the magnetic heads are provided on each of the magnetic heads arranged on both sides of the disk. A magnetic disk drive comprising an erase head drive circuit for driving all of the erase heads simultaneously.