JPH0462123B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement in a magnetic recording device that records and reproduces data on a magnetic recording medium using a magnetic head.

[Technical background of the invention and its problems]

For example, in magnetic recording devices using magnetic recording media such as floppy disks and magnetic drums,
Data is written and read while a magnetic head is brought into contact with the surface of a magnetic recording medium that is rotating at high speed. Generally, the magnetic head is composed of a head core, a recording/reproducing coil for writing/reading data, and an erase coil for erasing data, which are wound around the head core. The movement between the recording tracks of the recording medium is controlled.

However, the above magnetic recording device has the following problems. That is, the period when the magnetic head is moving between recording tracks, the period when the head load magnet is de-energized and the magnetic head is away from the surface of the magnetic recording medium, and the period when the rotation of the magnetic recording medium is stopped. etc., the magnetic head remains in the data reading state. As a result, a noise induced magnetic field caused by an external induced magnetic field is generated in the core of the magnetic head, and there is a risk that normal data recorded on the magnetic recording medium may be erased or rewritten with erroneous data.

In order to solve this problem, attempts have been made to short-circuit the back core of the magnetic head while the magnetic head is moving to suppress the generation of the noise-induced magnetic field. It has been difficult to completely prevent the negative impact on

[Purpose of the invention]

The present invention has been made based on the above circumstances, and its purpose is to short-circuit the head coil of a magnetic head when data is not being recorded or reproduced on a magnetic recording medium of the magnetic head. In this way, it is an object of the present invention to provide a magnetic recording device that can suppress the generation of noise-induced magnetic fields, protect recorded data, and improve reliability.

[Summary of the invention]

The present invention connects a switching element between both ends of a coil of a magnetic head, and sends a conductive signal to the switching element when the magnetic head is in a non-recording/reproducing state with respect to a magnetic recording medium. This is a magnetic recording device in which the coil of the magnetic head is short-circuited.

[Embodiments of the invention]

The present invention will be explained below using the drawings.

That is, the figure shows a magnetic head control circuit of a magnetic recording device according to an embodiment of the present invention.
In the figure, reference numeral 1 denotes a recording/reproducing coil wound around a recording/reproducing core (not shown). An erase coil 2 is wound around an erase core disposed close to the recording/reproducing core around which the recording/reproducing coil 1 is wound. The coils 1 and 2 and each core constitute a magnetic head.

A write signal (WDAT) line is connected to both terminals of the recording/reproducing coil 1, and a +
A driving voltage is applied from a 12V control power source via resistors 3a, 3b and diodes 4a, 4b. Further, diodes 5a and 5 are connected to the connection points between the resistors 3a and 3b and the diodes 4a and 4b.
An unillustrated amplifier (RAMP) for amplifying the readout signal is connected via b. Further, an intermediate tap of the recording/reproducing coil 1, that is, a common terminal 6, is connected to the +12V control power source via a resistor 7, and is also grounded via a resistor 8.
A transistor 9 is connected in parallel to this resistor 8 , and a write enable ( ) signal is input to the base of this transistor 9 via a resistor 10 and an inverter circuit 11 . One end of the erase coil 2 is connected to the common terminal of the recording/reproducing coil 1, and the other end is connected to +12V via a resistor 12.
connected to the control power supply.

FETs (field effect transistors) 13a are provided between both terminals of the recording/reproducing coil 1, between one end of the recording/reproducing coil 1 and the common terminal 6, and between the common terminal 6 and the end of the erase coil 2 on the resistor 12 side, respectively.
13b and 13c are connected. On the other hand, the head load signal that drives the head load magnet circuit and the FDK drive signal that drives the FDK motor drive circuit that rotationally drives a floppy disk (FDK) as a magnetic field recording medium are passed through the OR gate 14 to one of the OR gates 15. It is input to the input terminal. In addition, the step (STP) signal that drives the head motor drive circuit of the pulse motor that controls the movement of the magnetic head position is supplied to the monostable multivibrator 1.
6 to the other input terminal of the OR gate 15. The output terminal of this OR gate 15 is connected to each of the above through an inverter circuit 17 and a resistor 18.
It is connected to each gate of FET13a, 13b, and 13c. Furthermore, each FET13a, 13b, 1
Each gate of 3c is connected to a +12V control power supply via a resistor 19.

Next, the operation of the magnetic head control circuit of the magnetic recording apparatus constructed as described above will be explained. That is,
When the magnetic head is recording and reproducing data on the floppy disc, the write enable ( ) signal is in the "L" level of the on state, so the transistor 9 is in the on state and a current flows through the recording/reproducing coil 1 . Further, during recording and reproduction, both the head load signal and the FDK drive signal are in the on state. On the other hand, since the position of the magnetic head is fixed during recording and reproduction, the step (STP) signal does not include pulses. Therefore, monostable multivibrator 16 does not operate. As a result, the output of the OR gate 15 becomes "H" level, the output terminal of the inverter 17 becomes "L" level, and each FET
Since the voltage between the gate and source of 13a, 13b, 13c decreases, each FET 13a, 13b, 13c
is in a cut-off state. Therefore, the magnetic head normally performs recording and reproducing operations.

Next, in order to move the magnetic head to a different recording track, when a step (STP) signal containing a number of pulses corresponding to the number of rotational steps of the stepping motor is applied to the head motor drive circuit, the monostable multivibrator 16 is activated. It operates using pulses included in the step signal. That is, when a pulse is input to the monostable multivibrator 16, an "L" level pulse with a fixed time width determined by the time constant of the circuit is generated in synchronization with this pulse.
The time width of this pulse is set to be the sum of the time for the excitation phase of the stepping motor to move and the time for the vibrations generated when the stepping motor rotates one step and stops to decay. Therefore, the output of the OR gate 15 is at the "L" level while the pulse signal of the constant time width is output, and the output terminal of the inverter circuit 17 is at the "H" level. As a result, each FET13a, 13b, 1
Since the gate-source voltage of 3c increases, each
FETs 13a, 13b, and 13c become conductive.
Therefore, both terminals of each coil 1, 2 of the magnetic head are short-circuited.

Similarly, when the head load signal and FDK signal are off, the above FETs 13a, 13b, 13
c is conductive and each coil 1, 2 is short-circuited.

Therefore, when the magnetic head is in a state other than the recording/reproducing state, such as when the magnetic head is moving between recording tracks, when the magnetic head is away from the floppy disk, or when the floppy disk is not rotating, etc. When each coil 1 and 2 of the magnetic head
is in a short circuit condition. As a result, it is possible to suppress the generation of noise induced magnetic fields caused by external induced magnetic fields in the core of the magnetic head, and prevent normal data recorded on the floppy disk from being erased or rewritten with erroneous data. can. Therefore, recorded data can be protected.

Note that the present invention is not limited to the embodiments described above. In the embodiment, a floppy disk was used as the magnetic recording medium, but other magnetic recording media may be used.

〔Effect of the invention〕

As explained above, according to the present invention, when the magnetic head is not recording or reproducing data on a magnetic recording medium such as a floppy disk, the head coil of the magnetic head is short-circuited.
Therefore, the generation of noise-induced magnetic fields can be suppressed and recorded data can be protected, making it possible to improve the reliability of the entire recording device.

[Brief explanation of the drawing]

The figure is a magnetic head control circuit diagram of a magnetic recording device according to an embodiment of the present invention. 1... Recording/reproducing coil, 2... Erase coil, 9... Transistor, 11, 17... Inverter circuit, 13a, 13b, 13c... FET (switching element), 14, 15... OR gate,
16... Monostable multivibrator.

Claims (1)

[Claims] 1. In a magnetic recording device that records and reproduces data on a magnetic recording medium that runs while contacting the magnetic head by applying current to the head coil of the magnetic head, a switching device connected between both ends of the head coil of the magnetic head; Motoko and
A magnetic recording device comprising: detecting means for detecting a non-recording/reproducing state of the magnetic head on the magnetic recording medium, and transmitting a conduction signal to the switching element when the non-recording/reproducing state is detected. Device.