JPH04125905A - Magnetic core head for prepaid card - Google Patents

Abstract

PURPOSE:To obtain a magnetic core head having high magnetic flux density and high permeability, by laminating, in thickness direction, a specified number of sendust based alloy thin films whose thickness is smaller than or equal to a specified value. CONSTITUTION:An Fe-Si-Al allay flat plate composed of, e.g. Si: 8.5wt.%, Al: 5.5wt.% and Fe of residual part is manufactured. By mechanical working, bulk core material whose thickness is smaller than or equal to 0.1mm is taken out, which is laminated to form a bulk core of about 2.4mm in thickness. The magnetic flux density and the maximum permeability scarcely decease in the range from low frequency to about 10kHz which low frequency contains about 1kHz as the application frequency band at the time of recording in a prepayed card system. Thus the high magnetic flux density and the high permeability can be maintained. Hence, at the time of over write, process is enabled without leaving preceding signals, so that imperfect writing and reading can be reduced.

Description

[Detailed description of the invention] [Industrial application field] The present invention is a telephone card and a pachinko card.

The present invention relates to a magnetic held core used for recording and/or reproducing so-called prepaid cards such as stored cards.

[Conventional technology]

2. Description of the Related Art Conventionally, magnetic helad cores have been used to perform recording and/or reproduction on the magnetic surface of a magnetic card. Fe-5i-Al alloy (generally referred to as sendust) is widely used as a material for the magnetic head core because it has excellent magnetic properties, wear resistance, and corrosion resistance. The method for producing a magnetic helad core using this Fe-5i-Al alloy is to produce an ingot of Fe-5i-Al alloy, process the ingot into a flat plate by hot working, etc., and then cut and process the ingot into a flat plate. A method of manufacturing magnetic helad cores using so-called bulk materials, which is processed into a predetermined shape by machining such as grinding, and then annealed for the purpose of removing strain during processing and developing appropriate magnetic properties. The method is common.

On the other hand, a magnetic helad core for recording and/or reproducing magnetic tape is produced by processing a flat plate obtained by processing the Fe-3i-Al alloy ingot into a predetermined shape by machining such as cutting and grinding. At this time, reduce the thickness to 0.2
Cores manufactured by processing bulk core materials polished to a thickness of about 1.0 mm and laminating a large number of them by bonding them in the thickness direction with adhesive, and ultra-quenching molten metal of Fe-5i-Al alloy using a roll method. The core material is manufactured by laminating a large number of core materials in the thickness direction with an adhesive, and then polishing them. "Head" Publisher: Mimac Data System, published on October 15, 1981, etc.

On the other hand, in prepaid cards used in recent years, the coercive force (Hc) of the magnetic medium on the magnetic surface is approximately 800
What was 0e has improved to more than 27500e.

[Problem to be solved by the invention]

By the way, when recording and/or reproducing is performed on a prepaid card with a high coercive force of the magnetic surface of the magnetic medium using a magnetic head core or a laminated magnetic head core using the above-mentioned bulk material, before the card is saturated, The magnetic helad core becomes saturated with the input current, and when overriding (writing a different signal over a signal that has already been written to the magnetic medium), the previous signal may remain.

As a result, writing and reading errors will occur. On the other hand, in recent years, various kinds of printing have been performed on the surface of prepaid cards, and the thickness of the printing layer has become thicker. For this reason, the distance between the magnetic medium on the magnetic surface and the magnetic head core inevitably increases, and a magnetic head core that generates stronger magnetic flux and has higher magnetic permeability is required.

Furthermore, from now on, there will be a demand for prepaid cards that can be used for multi-purpose products, and in order to meet this demand, it will be necessary to improve the security of the information recorded on the card. Is it necessary to make the input/output signals even larger, or to make the input/output signals have more complex waveforms? There is also a demand for improved card recording density and improved playback/recording speed.

In order for a magnetic head to meet these demands, a magnetic rad core is required that has a large magnetic flux density, high magnetic permeability, and stable read/write characteristics from low frequencies to high frequencies. In other words, the frequency band used during recording in the private card system is in the range of 1 kHz to 10 kHz, and in terms of recording characteristics, the higher the magnetic flux density in this frequency band, the stronger the magnetic force can be used for writing, which is advantageous for high coercive force media. It is. Also, the playback characteristics are 1 kFlz
A larger maximum permeability in the frequency band of ~100 kHz is advantageous because it allows for faster reading.

Therefore, in order to meet the above demands, the present inventors aimed to develop a magnetic helad core with high magnetic flux density and high magnetic permeability, using Fe-5i-AI which has excellent wear resistance and corrosion resistance.
We have conducted repeated research using alloys with a particular focus on the behavior of magnetic properties. As a result, it was confirmed that a magnetic head core made of laminated thin plate core materials with a thickness of 0.1 mm or less has superior magnetic properties compared to a magnetic helad core made of bulk material. It was discovered that the magnetic properties are constant regardless of the number of laminated materials, and this led to the completion of the present invention.

(Means for Solving the Problems) The magnetic head core for prepaid cards according to the present invention, which was developed as described above, has a thickness of 0.1 mm.
It is formed by laminating a predetermined number of thin plates of the following sendust alloy in the thickness direction.

〔Example〕

Si: 8.5*t%, Al: 5.5wt%, remaining F
A Fe-3i-A1 alloy flat plate consisting of
．． 80. A bulk core material with a thickness of 100 μm and a bulk core material with a thickness of 120, 150, and 200 μm of a comparative example were taken, and the core materials were laminated for each thickness to produce a laminated bulk core with a thickness of 2.4 mm. In addition, a bulk core having a thickness of 2.4 mm was manufactured from the flat plate as a comparative material by machining. On the other hand, from a Fe-5i-A1 alloy molten metal with the same composition, a thickness of 6 mm was obtained using the twin roll method at a linear speed of 200 m/min.
01. tm ribbons according to the present invention were produced and laminated to produce a laminated core having the same shape as above.

Using these cores, the magnetic flux density when changing the frequency,
The maximum permeability was measured. This measurement result is shown in Figures 1 to 2.
As shown in the figure.

As is clear from Figures 1 and 2, 100 μm (0 μm)
, IIIQ+) In the core of the present invention, which is made of laminated core materials having a thickness of less than
z-10k) There is almost no drop from low frequencies including Iz to 1OkHz, and high magnetic flux density and high magnetic permeability can be obtained. , a decrease is seen in the range of 1 kHz to 10 kHz, and high magnetic flux density and high magnetic permeability cannot be obtained. In addition, the absolute value of the core of the present invention has a maximum magnetic permeability between 10 kHz and 100 kHz, which is more than twice that of the comparative example. It can read at high speed and has excellent playback characteristics.

In addition, as is clear from Figures 1 and 2, there is a tendency to obtain higher magnetic flux density and higher magnetic permeability by laminating thinner core materials, or the lower limit of the thickness of the core materials. As for 3
A thickness of about 0 μm is desirable; if it is thinner than this, it becomes difficult to manufacture the core material itself, and it also becomes difficult to laminate the core materials.

The reason why the laminated core of the ribbon obtained by the twin-roll method has the least deterioration in properties is that the crystal grains are finer than that of the core material obtained from bulk material, and as shown in Figure 3, the laminated core of the ribbon This is thought to be due to the metal structure in the cross section, or the structure having a granular layer in the center and columnar crystal layers above and below it.

Next, cores of various thicknesses were manufactured by changing the number of laminated layers of a 60 μm thick ribbon obtained by the twin roll method and a 60 μm thick thin plate core material obtained by machining. And 1kHz, 10kHz, 100kHz of these cores
The AC magnetic permeability (initial magnetic permeability) at 100 e and the maximum magnetic flux density at a magnetic field of 100 e were measured. The measurement results are shown in FIGS. 4 and 5, respectively.

As is clear from FIGS. 4 and 5, the AC magnetic permeability (initial magnetic permeability) and magnetic flux density are constant regardless of the number of laminated core materials, and the thickness according to the present invention is 100 μm (0.1 m
m) It can be seen that if the core material is as follows, there is no deterioration in magnetic properties no matter what thickness the laminated core is.

In the above explanation, the Fe-5i-A1 alloy was explained as a representative example of the sendust alloy according to the present invention, but other alloys such as Fe-5i-Co, Fe-5i-Ge, Fe
Of course, sendust alloys such as -Al-Ga are also applicable.

〔Effect of the invention〕

As described above, according to the magnetic head core for prepaid cards according to the present invention, magnetic properties of high magnetic flux density and high magnetic permeability can be obtained, so that it can be used for prepaid cards with high coercive force of the magnetic medium on the magnetic surface, and for various types of magnetic media on the surface. When overriding prepaid cards printed with , multi-purpose prepaid cards with a high density of recorded information, etc., it is possible to process without leaving any previous signals, thus preventing errors in writing to or reading from the prepaid card. can be reduced.

[Brief explanation of drawings]

Figures 1 and 2 are diagrams showing the magnetic flux density and maximum magnetic permeability when the frequency of the laminated core according to the present invention is changed, together with those of a comparative example, and Figure 3 is a diagram showing the core material according to the present invention. The cross-sectional metallographic diagrams of FIGS. 4 and 5 show the thickness of the laminated core according to the present invention and the core frequencies of 1kHz, 10kHz, and
FIG. 3 is a diagram showing the relationship between AC magnetic permeability (initial magnetic permeability) and magnetic flux density at kHz. Patent applicant Kobe Steel, Ltd.

Claims (1)

[Claims] A thin plate of sendust alloy with a thickness of 0.1 mm or less,
A magnetic head core for a prepaid card, characterized in that it is formed by laminating a predetermined number of sheets in the thickness direction.