JP2585558B2 - Multi-channel magnetic head - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a multi-channel magnetic head having a structure in which AC excitation type magnetic heads are arranged in a line.

(Technical Background of the Invention and Problems Thereof) A magnetic head is used to read data recorded on a magnetic card, a magnetic tape, or the like, or to read magnetic ink printed on a bill or the like. Conventionally used magnetic heads include an AC excitation type and a DC excitation type, which are described below.

That is, FIG. 6 shows an AC excitation type magnetic head 100 in which a primary coil 103 is wound around a center connecting arm portion 102 of a magnetic core 101 having a twin E-shape. Is connected to an AC power supply 104. A secondary coil 105 is wound on the upper side of the magnetic core 101, and a cancel coil 106 is wound on the lower side of the magnetic core 101, so that a detection object 110 such as a bill passes above the magnetic core 101. It has become. In such a configuration, the primary coil 103
Is excited by an AC power supply 104, and when a detection target 110 containing a magnetic material passes through the head surface above the magnetic core 101,
A signal corresponding to the amount or pattern of the magnetic material is output from the secondary coil 105. In this case, in order to remove a noise component and a bias component based on a fluctuation of the AC power supply 104 and a change in the temperature characteristic of the magnetic core 101, a difference from an output of the cancel coil 106 is obtained, and the difference signal is used as a magnetic signal. It has become.

In such an AC excitation type magnetic head, since the secondary coil 105 and the cancel coil 106 are wound around one magnetic core 101, the structure becomes large, and the detected object 11
In the case where all 0s are to be detected simultaneously, a plurality of magnetic heads 100 must be detected at predetermined intervals as shown in FIG. For this reason, the detection area becomes discrete, and high-precision detection is impossible, and there is a problem in discrimination of bills and the like that require this.

FIG. 8 shows a DC excitation type magnetic head 120 in which an excitation coil 122 is wound around one arm of a U-shaped magnetic core 121. A constant DC current I is supplied to the exciting coil 122. When the detection target 110 passes over the detection head surface, it corresponds to a time change of the magnetic material from which the DC component has been cut by the capacitor 123. The obtained differential signal is obtained as a detection signal V.

In such a DC excitation type magnetic head 120, since the detection signal V is obtained as a temporal change of the magnetic material, it cannot be detected in a stationary state, and the detection signal level varies depending on the relative speed. . Since this DC excitation type magnetic head 120 is small, there is also a type that is arranged in a line and detects a wide range simultaneously.
There is a fatal disadvantage as described above, and it is not suitable for detecting the amount of magnetism or the magnetic pattern of a bill or the like.

(Objects of the Invention) The present invention has been made in view of the circumstances described above, and an object of the present invention is to provide a magnetic recording system for a wide range simultaneously and in a stationary state, or without depending on the relative speed between a magnetic material and a magnetic head. It is an object of the present invention to provide a multi-channel magnetic head capable of accurately detecting an amount and a magnetic pattern.

(Summary of the Invention) The present invention relates to a structure of a multi-channel type magnetic head, in which a plurality of aligned magnetic cores each having a primary coil and a secondary coil wound therearound, a primary coil for cancellation and a secondary coil for cancellation. A structure comprising a cancel core wound with a next coil, and a member that integrally couples the plurality of magnetic cores and the cancel core, wherein detection surfaces of the magnetic cores face in a row with respect to a detection target. It is something that has become.

(Embodiment of the Invention) Fig. 1 shows an external configuration of a multi-channel type magnetic head 10 according to an embodiment of the present invention. Magnetic heads 11 to 19 whose structure is shown in FIG. 2A are provided in a line. In addition, a cancel head 20 whose structure is shown in FIG. 2B is provided at an end of the detection head surface of the case 1. Magnetic head 11
19 to 19 have the same configuration, and the description will be made here with reference to the magnetic head 11 shown in FIG. 2 (A). The magnetic head 11 has a U-shaped magnetic core 111.
A secondary coil 112 and a secondary coil 113 are wound respectively, and are arranged in the case 1 such that the detection surface 114 of the magnetic head 11 becomes the detection head surface of the multi-channel magnetic head 10 in FIG. You. The cross-sectional structure taken along line XX of FIG. 1 is shown in FIG. 3 (A).

The cancel head 20 has substantially the same structure as the magnetic heads 11 to 19, as shown in FIG. 2 (B).
The secondary coil 22 and the secondary coil 23 for cancellation are wound respectively, and the detection surface 24 of the cancellation head 20 is opposite to the detection head surface of the multi-channel magnetic head 10 in FIG. 1 is disposed at the end. FIG. 3 (B) shows the sectional structure taken along line YY of FIG. Since the output of the secondary coil 23 of the cancel head 20 is desirably smaller than the outputs of the magnetic heads 11 to 19, when driven by the same power supply,
The number of turns of the coils 22 and 23 is adjusted so that the output of the secondary coil 23 of the magnetic head 20 is smaller than the output of the secondary coil of each magnetic head.

As described above, the nine magnetic heads 11 to 19 and the one cancel head 20 are aligned in a line, are housed in the case 1, and are integrated.

The multi-channel type magnetic head 10 as described above is the fourth type.
Driven by a circuit as shown in the figure, magnetic signals M1 to M9 corresponding to the magnetic material of the object to be detected on the detection head surface are obtained in multiple channels. That is, the sine wave SW of a predetermined frequency output from the sine wave oscillator 2 is
Input to 39, constant current booster 30 cancel head 11
~ 19 primary coils are excited. The output of the secondary coil 23 of the cancel head 20 is a buffer amplifier 3
Are input to the differential amplifiers 41 to 49 through the magnetic heads 11 to 19
The detection signals S1 to S9 of each secondary coil are respectively differential amplifiers
41-49 are entered. The difference signals between the detection signals S1 to S9 obtained by the differential amplifiers 41 to 49 and the cancel signal CS are input to full-wave rectifier circuits 51 to 59, respectively, and the full-wave rectified signals are respectively sent to band-pass filters 61 to 69. The magnetic signals M1 to M9 are inputted and further outputted through the amplifiers 71 to 79.

In such a configuration, the operation is shown in FIGS.
This will be described with reference to the waveform diagram of FIG. The magnetic head
Since operations 11 to 19 are completely the same, the magnetic head 11 will be described here.

The constant current booster 31 is provided in the primary coil 112 of the magnetic head 11.
The secondary coil of the magnetic head 11 is supplied with a constant current of a predetermined frequency, and according to the magnetic material of the detection target such as a bill facing the detection head surface of the multi-channel magnetic head 10.
A detection signal S1 as shown in FIG. 5A is output from 113 and input to the differential amplifier 41. From the secondary coil 23 of the cancel head 20, a signal corresponding to a noise component irrelevant to the magnetic material of the object to be detected is output. The signal passes through the buffer amplifier 3 and is canceled as shown in FIG.
It is input to the differential amplifier 41 as CS. The difference signal S1A as shown in FIG. 5C obtained by the differential amplifier 41 is full-wave rectified by the full-wave rectifier circuit 51 as shown in FIGS. Only the envelope of the full-wave rectified signal passes through the band-pass filter 61, and the amplifier 71 outputs a magnetic signal M1 corresponding to the magnetic material as shown in FIG.

In the above description, an example has been described in which the magnetic material changes with time t, that is, the detection target moves relatively to the multi-channel magnetic head 10. The magnetic properties of the body can be obtained as a magnetic signal. In this case, one for each magnetic head 11 to 19
Since one cancel head 20 removes a noise component based on a fluctuation of the oscillator 2 or a change in temperature characteristic from a detection signal component, a magnetic signal can be obtained with high detection accuracy.

(Modification of the Invention) In the above embodiment, a multi-channel magnetic head is configured by arranging nine magnetic heads, but the number of magnetic heads is arbitrary. In the above description, one cancel head is provided at the end of the detection head surface. However, the number and arrangement position of the cancel heads are arbitrary, and the cancel signal does not change due to the magnetic material of the detection target. I just want to. Further, in the above description, each primary coil of the magnetic head and the cancel head is excited by a sine wave, but the sine wave is not necessarily required (for example, a rectangular wave).

(Effects of the Invention) As described above, according to the multi-channel magnetic head of the present invention, the plurality of AC excitation magnetic cores are arranged in a line, and the cancel core for removing noise is provided. The magnetic characteristics of the detection object can be detected as a whole and in a stationary state or without depending on the relative speed between the magnetic material and the magnetic head, and there is no influence from noise or the like. Also, by using a single canceling coil for noise removal, the entire structure becomes very simple, and the cost is greatly reduced as compared with a conventional arrangement of a plurality of AC excitation type magnetic heads. Achieved.

[Brief description of the drawings]

FIG. 1 is an external perspective view showing an embodiment of the present invention, FIGS. 2A and 2B are structural views showing an example of a magnetic head and a cancel head used in the present invention, and FIG. FIG. 1B is a cross-sectional structural view taken along line XX of FIG. 1, and FIG.
FIG. 4 is a block diagram showing an overall configuration example of the present invention, FIGS. 5A to 5F are waveform diagrams showing an operation example thereof, and FIG. 6 is a conventional AC excitation type magnetic head. FIG. 7 is a diagram showing an example of its use, and FIG. 8 is a diagram showing an example of the structure of a conventional DC excitation type magnetic head. 1. Case, 2. Sine wave oscillator, 10. Multi-channel magnetic head, 11-19 Magnetic head, 20 Cancel head, 30-39 Constant current booster, 41-49
... Differential amplifiers, 51-59 ... Full-wave rectifier circuits, 61-69 ... Bandpass filters, 71-79 ... Amplifiers.

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mio Mita 3-27-2 Kitahanada-cho, Sakai City Inside Minerva Co., Ltd. (56) References JP-A-50-123324 (JP, A) (JP, U)

Claims (1)

(57) [Claims] A plurality of aligned magnetic cores each having a primary coil and a secondary coil wound therearound; a cancel core having a primary coil for cancellation and a secondary coil for cancellation wound thereon; A multi-channel magnetic head comprising a magnetic core and a member integrally connecting the cancel core, wherein a detection surface of each of the magnetic cores faces in a line with respect to a detection target. .