JPH026486Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to a floppy disk device, and more particularly to a floppy disk device capable of writing and erasing data using a magnetic head having a single gap.

Prior Art Straddle type and tunnel type magnetic heads have conventionally been used for writing and reading signals on the surface of a floppy disk. These magnetic heads have separate gaps for writing and erasing. 6th
The figure shows a partially cutaway plan view of a straddle type magnetic head. A writing and reading gap a is formed by the cores 2 and 3, and erasing gaps b and c are formed by the erasing cores 4 and 5 on both sides of the cores 2 and 3.

Problems to be Solved by the Invention In such a magnetic head, the gap a for writing and reading and the gaps b and c for erasing are formed separately, and the cores 2 and 3 for writing and reading are formed separately. In addition, cores 4 and 5 for erasing are required. For this reason, the structure of the magnetic head 1 becomes complicated,
This poses a problem in that it becomes expensive.

The motor and magnetic head account for a large proportion of the price of a floppy disk, and the price is influenced by these factors.

Means for Solving the Problem The present invention uses a single-gap head in which a wide core and a narrow core are butted against each other, and when erasing, a magnetizable current is passed through the head winding over the entire width of the wide core. The object of the present invention is to provide a floppy disk device that can perform erasing and writing with a magnetic head having a simple structure and a single gap by passing a small current capable of magnetizing the entire width of a narrow core during writing.

Another purpose is to realize an inexpensive floppy disk device.

Embodiment FIG. 1 shows a perspective view of a single-gap magnetic head applied to the present invention, and FIG.
A partially cutaway plan view is shown. Note that the same parts as in FIG. 4 will be described with the same reference numerals.

6 is a single-gap magnetic head, 7 is a wide core, 8 is a narrow core, and a is a gap formed by butting these cores 7 and 8 together.

Since there is only one gap in this way, erasing and writing operations are performed independently and separately. That is, the track on the disk to which data is to be written is erased, and then data is written.

Erasing is performed on the disk by passing a large direct current through the winding 9, using the core width _l1 of the wide core 7. Further, in writing, data is written in the width of the core width l ₂ of the narrow core 8 by flowing a current smaller than that in erasing.

FIG. 3 is a diagram showing the overwrite characteristics of the head. When the write current is smaller than the A point, the magnetic influence remains within l ₂ width, and when it becomes larger than the A point, the magnetic influence extends to l ₁ width. This characteristic can be accurately determined by recording data at a certain current value and measuring the characteristics of the output voltage due to off-track (deviation of the read head from the write track on the disk surface). An example of this is shown in Figure 4. When the current is small, the line appears as a solid line, and as the current increases, it approaches a dotted line.
As you can see from this figure, if a large DC current flows, l ₁
It can be seen that the erasing effect can be obtained with the width of .

FIG. 5 shows a circuit using a single gap head according to an embodiment of the present invention. The circuit within the dotted line shows a circuit for switching the current for erasing in such a magnetic head 6. Resistors R ₁ and R ₂ , capacitor C ₁ and AND gate 10 are a circuit for detecting an erase signal. Note that this circuit becomes unnecessary if the erase signal can be directly supplied. Terminal 11
When a low level L signal is supplied to the terminal 12 and a high level H signal is supplied to the terminal 12, an erasing operation is performed. That is, the output of the AND gate 10 becomes H, the transistor _Q3 is turned on, the resistor _R5 is shot, and the head 6 is turned on.
A large current for erasing is applied. The Q output of flip-flop FF14 becomes L because there is a reset signal until before the erase operation, and the output becomes H.
becomes. As a result, the output of the NAND gate 15 becomes L, and the transistor _Q2 is turned on. The on-current of _Q2 flows through the head 6 and resistors _R5 and _R6 .
The erase current is adjusted by resistor _R6 .

When writing data, the write data is L and H.
As a result, the transistor Q ₄ is turned on by the filter consisting of resistors R ₁ and R ₂ and capacitor C ₁ , and the output of the AND gate 10 becomes L, turning off the transistor Q ₃ and not being in the erased state.

With the configuration and operation described above, by first erasing the surface of the disk to be written and then writing data in the normal manner, it is possible to obtain the same effect as a head with erasing such as a straddle type.

Effects In the above-described floppy disk device according to the present invention, in a magnetic head in which a wide core and a narrow core are butted against each other to form a single gap, the entire width of the wide core can magnetize the surface of the floppy disk during erasing. An erasing current is passed through the winding of the head, and when data is written, a current smaller than the erasing current is passed through the winding of the head, so that the floppy disk surface is magnetized over the entire width of the narrow core. Therefore, a magnetic head with a simple structure can be used, and the price can be less than half that of a conventional head having multiple gaps, thereby making it possible to provide an inexpensive floppy disk device.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a magnetic head applied to the present invention, FIG. 2 is a partially cutaway plan view of the magnetic head shown in FIG. 1, and FIGS. 3 and 4 are an embodiment of the present invention. FIG. 5 shows a circuit diagram of an embodiment of the present invention, and FIG. 6 shows a conventional magnetic head. 6...Single gap magnetic head, 7...Wide core, 8...Narrow width core, a...Write gap.

Claims (1)

[Scope of utility model registration request] In a magnetic head in which a wide core and a narrow core are butted against each other to form a single gap, an erasing current that can magnetize the surface of the floppy disk over the entire width of the wide core is passed through the winding of the head during erasing. A floppy disk device characterized in that the floppy disk surface is magnetized over the entire width of the narrow core by passing a current smaller than the erase current through the winding of the head during writing.