JP2634677B2 - Advanced erase type magnetic head device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a preceding erase type magnetic head device mounted on a floppy disk device.

[Prior Art] FIG. 7 is a perspective view showing a main part of a conventional erasure type magnetic head device for a conventional floppy disk device disclosed in, for example, Japanese Utility Model Laid-Open Publication No. 61-111016, and FIG. FIG. 3 is a wiring diagram of a read / write coil and an erase coil during signal reproduction. In the figure, (1) is a read / write core, (2) is an erase core, and (3) is these cores (1).
A center core for forming a read / write gap (1a) and an erase gap (2a) with (2), (3a) a non-magnetic material layer provided in the center core (3), and (4) a magnetic circuit A back bar for closing, (4a) a nonmagnetic layer provided in the back bar (4), (5) a read / write coil wound around the read / write core (1), (6)
Is an erase coil wound around the erase core (2),
(7) is a read / write dump resistor connected to both ends of the read / write coil (5), (8) is an erase dump resistor connected to both ends of the erase coil (6), (9)
Is a read / write circuit, (10) is an erase circuit, and (11) is a floppy disk of a magnetic head (not shown).
Sliding surface.

In the above configuration, at the time of signal recording, the sliding surface (11) is recorded on the floppy disk by the signal read / write gap (1a) from the read / write circuit (9) while sliding on the floppy disk. Prior to the gap (1a), the data previously recorded is erased by the erase gap (2a) by the erase signal from the erase circuit (10). Similarly, during reproduction, the erase signal (2a) precedes the read / write gap (1a), and the sliding surface (11) slides on the floppy disk, while the magnetization signal recorded on the floppy disk is read. It is detected by the write gap (1a), is electromagnetically converted by the read / write coil (5), and is output to the read / write circuit (9) as a reproduction voltage. Further, a magnetization signal is also detected from the erase gap (2a), and a magnetic flux due to the magnetization signal is generated in the erase core (2), and is electromagnetically converted by the erase coil (6) to output a reproduction voltage, but is not processed as a signal. . At this time, the magnetic flux in the erase core (2) leaks to the read / write core (1), and there is a possibility that an erase crosstalk voltage is output from the read / write coil (5) due to the leaked magnetic flux. Blocked by the magnetic layers (3a) and (4a), the occurrence of erase crosstalk is reduced. The erase dump resistor (8) provided between the terminals of the erase coil (6) is for absorbing a surge when an erase current is applied during signal recording, and has a resistance value of the DC of the erase coil (6). The value is much larger than the resistance value.

[Problem to be Solved by the Invention] Since the conventional prior erase type magnetic head device is configured as described above, the erase cross caused by the magnetic flux detected by the erase gap is provided by the nonmagnetic layer provided in the center core. Although the talk was reduced, the provision of the nonmagnetic layer in the center core deteriorated the read / write core's reproduction efficiency, causing the S / N ratio to deteriorate.
In addition, there was a problem that pseudo gap noise was generated by the nonmagnetic layer itself, and finally the S / N ratio was considerably deteriorated, and furthermore, the manufacturing of the center core was complicated, the yield was reduced, and the cost was accordingly higher. .

The present invention has been made in order to solve the above-described problems, and has as its object to obtain an inexpensive preceding erase-type magnetic head device capable of reducing erase crosstalk and maintaining a high S / N ratio. And

Means for Solving the Problems A preceding erase type magnetic head device according to the present invention comprises a read / write core having a read / write coil wound thereon, an erase core having an erase coil wound therewith,
A read / write gap and an erase gap are formed between these two cores. A center core having no nonmagnetic layer inside; and an erase coil short-circuit means for short-circuiting the erase coil end with a DC resistance value equal to or less than the DC resistance value of the erase coil during signal reproduction, thereby suppressing crosstalk noise. Things.

[Operation] The leading erase type magnetic head device according to the present invention includes:
Since the erase coil terminals are short-circuited during signal reproduction,
A current is generated in the erase coil by the magnetic flux flowing through the erase core, and the self-inducing action of the current cancels the erase crosstalk magnetic flux leaking from the erase core through the center core into the read / write core during reproduction.

An embodiment of the present invention will be described below with reference to the drawings. First
FIG. 1 is a perspective view showing a main part of a magnetic head device according to an embodiment of the present invention, and FIG. 2 is a wiring diagram of a read / write coil and an erase coil thereof. In the figure, (1) is a read / write core, (1a) is a read / write gap,
(2) is the erase core, (2a) is the erase gap,
(3) is a center core, (4) is a back bar, (4a) is a nonmagnetic layer, (5) is a read / write coil, (6) is an erase coil, (7) is a read / write dump resistor,
(8) is an erase dump resistor, (9) is a read / write circuit, (10) is an erase circuit, and (11) is a sliding surface of a magnetic head. The above is the same as the conventional example shown in FIG. .
However, no non-magnetic layer is provided in the center core (3). (12) is a short-circuit element such as an analog switch connected between the terminals of the erase coil (6), and (13) is an erase coil short-circuit means for turning on the short-circuit element (12) during reproduction.

Next, the operation will be described. At the time of signal recording, the erase coil short-circuit means (13) does not output a short-circuit signal in response to a write signal from the read / write circuit (9), and the short-circuit element (12) remains open. Then, the erase gap (2a) slides on the floppy disk on the sliding surface (11) ahead of the read / write gap (1a), and the erase gap (2a) causes an erase signal from the erase circuit (10). The previously recorded data is erased, and the signal from the read / write circuit (9) is recorded on the floppy disk by the read / write gap (1a). At the time of reproduction, the erase coil short-circuit means (13) outputs a short-circuit signal in response to a read signal from the read / write circuit (9), the short-circuit element (12) is turned on, and both ends of the erase coil (6) are connected to the DC resistance of the erase coil. Short circuit with DC resistance less than the value.
Therefore, at the time of reproduction, the self-inducing action of the magnetic flux passing through the erase coil (6) detected in the erase gap (2a) generates a back electromotive force in a direction that hinders the change of the magnetic flux, causing a current to flow. Erasure reproducing magnetic flux passing through the read / write circuit (9) is eliminated, and erase crosstalk to the read / write circuit (9) is reduced.

FIG. 3 is a configuration diagram of a conventional magnetic head which does not short-circuit the erase coil (6) during reproduction without providing a non-magnetic layer in the center core (3), and FIG. 4 shows an erase coil (6) having a similar configuration. configuration view of a magnetic head of an embodiment of the present invention for short-circuiting, FIG. 5 is a waveform diagram showing a reproduced signal voltages V ₁ between the third diagram of the read write coil (5) terminal, Figure 6 is Figure 4 in waveform diagram showing a read-write coil (5) reproducing the signal voltage V ₂ between the terminals (14) is reproduced signal waveform detected by the read-write gap (1a), (15) are erase crosstalk waveforms. As is apparent from the figure, the erase crosstalk can be reduced without providing a nonmagnetic layer in the center core (3), the S / N ratio is improved, and the read error is reduced.

[Effect of the Invention] As described above, according to the present invention, the erase coil short-circuit means for short-circuiting the erase coil end with a DC resistance value equal to or less than the DC resistance value of the erase coil at the time of signal reproduction is provided. The amount can be greatly reduced, and there is no need to provide a non-magnetic layer on the center core. Therefore, there is an effect that an inexpensive erasure type magnetic head device having a simple structure and a low cost can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a main part of a preceding erase type magnetic head device according to an embodiment of the present invention, FIG. 2 is a wiring diagram of a read / write coil and an erase coil thereof, and FIG. FIG. 4 is a configuration diagram of a conventional magnetic head having no magnetic layer, FIG. 4 is a configuration diagram of a magnetic head according to an embodiment of the present invention, FIG. 5 is a reproduction voltage waveform diagram of the magnetic head according to the configuration of FIG. 6 is a reproduction voltage waveform diagram of the magnetic head having the configuration of FIG. 4, FIG. 7 is a perspective view showing a main part of a conventional magnetic head for a floppy disk drive, and FIG. 3 is a wiring diagram of the erase coil. FIG. In the figure, (1) is a read / write core, (1a) is a read / write gap, (2) is an erase core, (2a) is an erase gap, (3) is a center core, (5) is a read / write coil, and (6). Is an erase coil, (9) is a read / write circuit, (10) is an erase circuit, (12) is a short-circuit element, and (13) is an erase coil short-circuit means for turning on the short-circuit element (12) during reproduction. The same reference numerals in the drawings indicate the same or corresponding parts.

Claims (1)

(57) [Claims] A read / write core wound with a read / write coil, an erase core wound with an erase coil, and a read / write gap and an erase gap formed between the two cores. A center core having no magnetic layer, and erase coil short-circuit means for short-circuiting the erase coil end with a DC resistance value equal to or less than the DC resistance value of the erase coil during signal reproduction, thereby suppressing crosstalk noise. Preceding erase type magnetic head device.