JPH03187005A - Advance erase type magnetic head device - Google Patents

Abstract

PURPOSE:To considerably reduce the quantity of crosstalk noise by providing an erase coil short-circuiting means which short-circuits the ends of an erase coil with a DC resistance value smaller than that of this erase coil at the time of signal reproducing. CONSTITUTION:At the time of signal recording, an erase coil short-circuiting means 13 does not output a short-circuit signal in accordance with the write signal from a read/write circuit 9, and a short-circuit element 12 is kept open. Then, an erase gap 2a is slided on a floppy disk of a slide face 11 before a read/write gap 1a, and previously recorded data is erased in accordance with the erase signal from an erase circuit 10 by the gap 2a, and the signal from the read/write circuit 9 is recorded on the floppy disk by the gap 1a. At the time of reproducing, the erase coil short-circuiting means 13 outputs the short- circuit signal in accordance with the read signal from the circuit 9, and the short-circuit element 12 is turned on to short-circuit both ends of an erase coil 6. Thus, a counter-electromotive force is generated by the self-induction action due to the magnetic flux passing the coil 6 to reduce the erase crosstalk to the circuit 9.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a floppy disk device, particularly to improving the reliability of a magnetic recording head mounted thereon.

[Prior Art] FIG. 7 is a perspective view showing the main parts of a conventional magnetic head for a floppy disk device disclosed in, for example, Japanese Utility Model Application No. 61-111016, etc., and FIG. FIG. 3 is a wiring diagram of a read/write coil and an erase coil. In the figure, (1) is a read/write core, (2) is an erase core, and (3) is a read/write gap (la) and an erase gap (la) between these cores (1) and (2).
2a), (3a) is a non-magnetic layer provided in the center core (3), (4γ is a back bar for closing the magnetic circuit, (4a) is a back bar provided in the back bar (4), The provided non-magnetic layer (5) is 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 the erase dump resistor connected to both ends of the erase coil (6), (9) is the read/write circuit, (10) is the erase circuit, and (11) is the sliding of the magnetic head with the floppy disk (not shown). It is a surface.

In the above configuration, during signal recording, the sliding surface (11) slides on the floppy disk while the signal from the read/write circuit (9) is recorded on the floppy disk by the read/write gap (1a). Erase gap (2a) precedes write gap (1a)
The previously recorded data is erased by the erase signal from the erase circuit (10). Similarly, during playback, the erase gap (2a) is the same as the read/write gap (1a).
), while the sliding surface (11) slides on the floppy disk, the magnetization signal recorded on the floppy disk is detected by the read/write gap (la), and is electromagnetically generated by the read/write coil (5). The converted voltage is output to the read/write circuit (9) as a reproduction voltage. In addition, a magnetization signal is also detected from the erase gap (2a), and the resulting magnetic flux is generated in the erase core (2), which is electromagnetically converted by the erase coil (6) and outputs a reproduction voltage, but is not processed as a signal. . At this time, the magnetic flux in the erase core (2) may leak to the read/write core (1), and this leakage magnetic flux may cause the read/write coil (5) to output an erase crosstalk voltage.
This leakage magnetic flux is blocked by the nonmagnetic layers (3a) and (4a), and the occurrence of erase crosstalk is reduced. The erase dump resistor (8) installed between the erase coil (6) terminals is used to handle surges when the erase current is passed during signal recording, and its resistance value is equal to the DC resistance of the erase coil (6). The value is much larger than the value.

[Problems to be Solved by the Invention] Since the conventional magnetic head device is configured as described above, the erase crosstalk caused by the magnetic flux detected by the erase gap is reduced by the nonmagnetic layer provided in the center core. However, since the non-magnetic layer is provided in the center core, the regeneration efficiency of the read/write core deteriorates, and S
This caused the deterioration of the /N ratio. In addition, pseudo-gap noise occurs due to the non-magnetic layer itself, which ultimately results in a considerable deterioration of the S/N ratio.Furthermore, manufacturing of the center core is complicated, resulting in lower yields and higher costs. The invention was made to solve the above problems, and it reduces erase crosstalk and has a high S.
An object of the present invention is to obtain an inexpensive floppy disk device equipped with a magnetic head device capable of maintaining the /N ratio.

[Means for Solving the Problems] A floppy disk device according to the present invention is provided with an erase coil short-circuiting means for short-circuiting the end of the erase coil of the magnetic head device with a DC resistance value that is less than the DC resistance value of the erase coil during signal reproduction. It is something that

[Function] In the floppy disk device of the present invention, the erase coil terminals are short-circuited during signal reproduction, so a current is generated in the erase coil due to the magnetic flux flowing in the erase core, and the self-induction effect of the current generates erase crosstalk. Magnetic flux is canceled.

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

FIG. 1 is a perspective view showing essential parts 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 an erase core, (2a) is
is the erase gap, (3) is the center core, (4) is the back bar, (4a) is the non-magnetic layer, (5) is the read/write coil, (6) is the erase coil, (7) is the read/write dump resistor , (8) is the erase dump resistance, (9
) is the read/write circuit, (10) is the erase circuit, (1
1) is the sliding surface of the magnetic head, which is similar to the conventional example shown in FIG. However, the center core (3)
No non-magnetic layer is provided inside.

(12) is a shorting element such as an analog switch connected between the terminals of the erase coil (6), and (13) is an erase coil shorting means that turns on the shorting element (12) during reproduction.

Next, the operation will be explained. During signal recording, the erase coil shorting means (13) does not output a shorting signal in response to a write signal from the read/write circuit (9), and the shorting element (
12) remains open. Therefore, the erase grab (28) slides on the floppy disk on the sliding surface (11) in advance of the read/write gap (1a), and the erase gap (2a) causes the erase signal from the erase circuit (10) to move forward. The data recorded in the read/write circuit (Ia) is erased and the data recorded in the read/write circuit (
9) is recorded on the floppy disk. During reproduction, the erase coil shorting means (13) outputs a shorting signal in response to the read signal from the read/write circuit (9), and the shorting element (12) is turned on to close the erase coil (6).
) are shorted. Therefore, during playback, due to the self-induction effect caused by the magnetic flux detected in the erase gap (2a) and passing through the erase coil (6), a back electromotive force is generated in the direction that prevents changes in the magnetic flux, and a current flows through the erase core (2). The erase reproduction magnetic flux passing through the read/write circuit (9) is canceled, and the erase crosstalk to the read/write circuit (9) is reduced.

Figure 3 is a configuration diagram of a conventional magnetic head that does not provide a non-magnetic layer in the center core (3) and does not short-circuit the erase coil (6) during playback. Figure 4 shows a similar configuration with the erase coil (6) FIG. 5 is a waveform diagram showing the reproduced signal voltage ■1 between the read/write coil (5) terminals of FIG. 3, and FIG. This is a waveform diagram showing the reproduced signal voltage ■2 between the terminals of the read/write coil (5), where (I4) is the read/write gap (1a
) is the detected reproduced signal waveform, and (15) is the erase crosstalk waveform. As is clear from the figure, even without providing a nonmagnetic layer in the center core (3), erase crosstalk can be reduced, the S/N ratio is improved, and read errors are reduced.

[Effects of the Invention] As described above, according to the present invention, an erase coil short-circuiting means is provided for short-circuiting the end of the erase coil with a DC resistance value lower than the DC resistance value of the erase coil during signal reproduction, so that the center core Even without a non-magnetic layer, the amount of crosstalk noise can be significantly reduced, the configuration of the magnetic head device can be simplified, and an inexpensive floppy disk device can be obtained.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the main parts of a magnetic head device according to an embodiment of the present invention, FIG. 2 is a wiring diagram of its read/write coil and erase coil, and FIG. 3 is a non-magnetic layer in the center core. FIG. 4 is a configuration diagram of a conventional magnetic head that is not provided with a magnetic head. FIG. 4 is a configuration diagram of a magnetic head according to an embodiment of the present invention.
The figure is a reproduction voltage waveform diagram of the magnetic head with the configuration shown in Figure 3.
Fig. 6 is a reproduction voltage waveform diagram of the magnetic head with the configuration shown in Fig. 4, Fig. 7 is a perspective view showing the main parts of a conventional magnetic head for a floppy disk device, and Fig. 8 is a read/write diagram during signal reproduction. It is a wiring diagram of a coil and an erase coil. In the figure, (1) is a read/write core, (1a) is a read/write gap, (2) is an erase core, (2a) is
is the erase gap, (3) is the center core, (5) is the read/write coil, (6) is the erase coil, (9)
is a read/write circuit, (10) is an erase circuit, (12) is an erase circuit, and (12) is an erase circuit.
) is a shorting element, and (13) is an erase coil shorting means that turns on the shorting element (12) during reproduction. The same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] Equipped with a magnetic head device that includes a read/write core around which a read/write coil is wound, an erase core around which an erase coil is wound, and a center core that forms a read/write gap and an erase gap between these two cores. A floppy disk device, characterized in that the floppy disk device is provided with erase coil shorting means for shorting the end of the erase coil with a DC resistance value that is less than a DC resistance value of the erase coil during signal reproduction.