JP2009122240A - Magnetic detection apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic detection apparatus which simplifies an electric circuit, and which greatly reduces cost and downsizes an apparatus itself. <P>SOLUTION: The magnetic detection apparatus includes a transformer 100 with an output coil and a driving coil which have differential connection, an adjusting means 107 for adjusting the electromagnetic property in the transformer, an AC signal generating means for generating a first AC signal with a prescribed electrical property which is applied to the driving coil and a phase difference detecting means for detecting the phase difference between a second AC signal outputted by an output coil by having the driving coil driven by the first AC signal and the first AC signal. The adjusting means adjusts the electromagnetic property of the transformer so that the phase difference between the first AC signal and the second AC signal detected by the phase difference detection means becomes a prescribed value or else within the prescribed range which are set beforehand, in a magnetic body environment in which concentration of the magnetic body is set beforehand at the prescribed value or else within the prescribed range. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a magnetic detection device that detects the concentration (also referred to as bulk density) of a magnetic material, and more particularly to adjustment of its detection characteristics.

  An apparatus using a differential transformer is known as a magnetic substance detection apparatus for detecting the remaining amount and density of toner or developer containing a magnetic substance component in an electrophotographic image forming apparatus. Patent Documents 1 and 2 disclose that this type of magnetic detection device has a problem that the detection characteristics vary depending on differences in characteristics of individual differential transformers caused by assembly and manufacture.

  As a technique for solving the above problem, a circuit mechanism capable of adjusting the phase of the output signal is installed inside the apparatus, and an electric signal whose voltage level can be changed is input to the circuit mechanism from the outside of the apparatus. Techniques for adjusting the characteristics are known (Patent Document 1 and Patent Document 2).

  FIG. 9 shows a schematic configuration diagram of a conventional magnetic detection circuit. In FIG. 9, 1000 is a differentially connected differential transformer, 902 is a drive circuit for driving the differential transformer 1000, 903 is a phase comparison circuit, 904 is a variable capacitance diode, and 905 is a control circuit.

In FIG. 9, a differential transformer 1000 is driven by a drive circuit 902 to generate a differential output Eo corresponding to the remaining amount of toner. The differential transformer 1000 includes a drive coil 1060 and two output coils 1040 and 1050. The output coils 1040 and 1050 are differentially connected to obtain a differential output Eo corresponding to the remaining amount of toner. The drive circuit 902 is configured as a Colpitts type oscillation circuit including a drive coil 1060 and capacitors 201 and 202, and drives the differential transformer 100 with a signal of an oscillation frequency.
The phase comparison circuit 903 compares the phase of the differential output Eo output from the output coils 1040 and 1050 of the differential transformer 1000 and the reference signal Ed supplied from the drive circuit 902, and detects the detection signal Vo corresponding to the phase difference. Is obtained.
When a circuit that averages the detection signal Vo is added to the output terminal of the detection signal Vo, as shown in FIG. 10, a characteristic that the output voltage changes according to the concentration of the magnetic material is obtained (vertical axis). The detection signal voltage Vo [V] is arranged on the horizontal axis, and the magnetic substance concentration [au: arbitrary unit] is arranged on the horizontal axis). Thereby, the magnetic body density in the environment where the differential transformer is installed can be detected by the above method.

Here, in the conventional example, the following method is proposed as a solution to the problem that the detection characteristic changes due to the characteristic change of the differential transformer 1000 as described above. That is, a diode 904 having a variable capacitance according to the applied voltage value is connected between the drive coil 1060 and the output coils 1040 and 1050 of the differential transformer 1000 that are differentially connected. Then, by changing the applied voltage Vcnt to the diode 904 and changing the phase difference between the drive coil 1060 and the output coils 1040 and 1050, as shown in FIG. A method to change the voltage characteristics is proposed.
The same parts in FIGS. 10 and 11 are denoted by the same reference numerals, and detailed description is omitted in the prior art document (Patent Document 1), and the description thereof is omitted here. It is proposed that the differential output Eo is adjusted and the detection signal Vo is adjusted by this method (Patent Document 1 and Patent Document 2).
Japanese Patent No. 0364321 Japanese Patent Laid-Open No. 06-289717

  However, in the above-described conventional example, an adjustment circuit is added in the magnetic detection device to adjust a variation due to a difference in characteristics of each differential transformer and a change in characteristics caused by variations in electric components of a constituent circuit. Yes. As a result, the electric circuit constituting the apparatus is complicated, resulting in increased costs and difficulty in downsizing the apparatus.

  The present invention has been made under such circumstances, and it is an object of the present invention to provide a magnetic detection device that simplifies an electric circuit and can greatly reduce the cost and size of the device itself. It is.

  In order to solve the above problems, in the present invention, the magnetic detection device is configured as described in the following (1) to (8).

(1) An output coil that outputs a detection signal corresponding to the magnetic environment, a drive coil differentially connected to the output coil, a transformer having the output coil and the drive coil, and an electromagnetic in the transformer Adjusting means for adjusting characteristics; AC signal generating means for generating a first AC signal having a predetermined electrical characteristic applied to the drive coil; and driving the drive coil by the first AC signal. A phase difference detection means for detecting a phase difference between the second AC signal output from the output coil and the first AC signal,
The adjusting means is configured to detect the first alternating current signal and the second alternating current signal detected by the phase difference detecting means in the magnetic environment where the magnetic substance concentration is set to a predetermined value or a predetermined range in advance. A magnetic detection device that adjusts the electromagnetic characteristics of the transformer so that the phase difference between and becomes a predetermined value set in advance or a phase difference within a predetermined range.

(2) In the magnetic detection device according to (1),
A magnetic sensing device comprising amplification means for amplifying the second AC signal.

(3) In the magnetic detection device according to (1),
The magnetic detecting device is a means for changing the inductance of the transformer.

(4) In the magnetic detection device according to (1),
The magnetic detecting device, wherein the adjusting means is means for changing an electrical characteristic of the first AC signal.

(5) In the magnetic detection device according to (4),
The electrical characteristic of said 1st alternating current signal is a magnetic detection apparatus which is a frequency.

(6) An output coil that outputs a detection signal corresponding to the magnetic environment, a drive coil differentially connected to the output coil, a transformer having the output coil and the drive coil, and an electromagnetic in the transformer Adjusting means for adjusting the characteristics;
AC signal generating means for generating a first AC signal having a predetermined electrical characteristic to be applied to the drive coil, and output from the output coil by driving the drive coil with the first AC signal A phase difference detecting means for detecting a phase difference between a second AC signal and the first AC signal,
The adjusting means includes first means for changing inductance in the transformer and second means for changing electrical characteristics of the first AC signal, and a magnetic substance concentration is a predetermined value in advance, or In the magnetic environment set in a predetermined range, a phase difference between the first AC signal and the second AC signal, which is detected by the phase difference detection unit, is set to a predetermined value, or a predetermined value. A magnetic detection device that adjusts the electromagnetic characteristics of the transformer so as to achieve a phase difference in a range.

(7) In the magnetic detection device according to (6),
A magnetic detection device that is adjusted in advance by the first means and adjusted by the second means at the time of magnetic detection.

(8) In the magnetic detection device according to (6) or (7),
The electrical characteristic of said 1st alternating current signal is a magnetic detection apparatus which is a frequency.

  According to the present invention, by having an adjustment mechanism capable of adjusting the electromagnetic characteristics of the transformer, the electric circuit constituting the device can be simplified, and the cost of the device itself can be greatly reduced. Miniaturization is possible.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to examples.

FIG. 1 shows a schematic configuration diagram of a “magnetic detection device” according to the first embodiment.
In FIG. 1, reference numeral 100 denotes a differential transformer, and drive coils 104 and 105 are differentially connected and have an output coil 106. 101 is an AC signal generator (corresponding to AC signal generating means for generating the first AC signal in the claims), and inputs an AC signal Ein having predetermined electrical characteristics to the drive coils 104 and 105. The drive coils 104 and 105 are driven. Further, by connecting to the output coil 106 via the resistor R1, the output signal Eout (equivalent to the second AC signal in the claims) output from the output coil 106 is stabilized. An amplifier 102 amplifies the output signal output from the output coil 106. A phase difference detector 103 receives an input signal Ein input to the drive coils 104 and 105 and an output signal Eout output from the output coil 106 via the amplifier 102, and detects a phase difference between the two signals.

  Here, the configuration of the differential transformer 100 shown in the present embodiment is different from the configuration of the differential transformer 1000 described above with reference to FIG. 9, but the differential transformer circuit uses an output coil due to its reversibility. It has been disclosed in the prior art that a circuit operation similar to that in the case of differential connection can be obtained.

  FIG. 8 shows an electric circuit diagram of the magnetic detection device of this embodiment. The examples are not intended to limit the invention. Further, the description of the portions where the reference numerals overlap with those in FIG. 1 is omitted. In FIG. 8, J1 to J4 indicate connectors to the external component means, and the AC signal Ein from the AC signal generator 101 in FIG. 1 is input to J1. The power supply voltage Vin is input to J2, and is used as the power supply voltage of the inverter IC1 corresponding to the amplifier 102 in FIG. 1 through the filter circuit formed by the resistor R3 and the capacitor C3. R2 is an amplification feedback resistor of the inverter IC1. The output coil 106 and the capacitor C1 constitute a tuning circuit, and the output signal Eout amplified by the coupling capacitor C2, the inverter IC1, and the feedback resistor R2 is output from J3. A GND is connected to J4.

  FIG. 2 is a timing chart showing a detection method of the phase difference detector 103. The first stage in FIG. 2 is a basic clock Ck for operating the phase difference detector 103, the second stage is a signal Ein that is input to the drive coils 104 and 105 to drive the coil, and the third stage is an amplifier from the output coil 106. An output signal Eout output via 102 is shown. As described above, the output signal Eout (corresponding to the detection signal corresponding to the magnetic substance environment in the claims) has a phase difference corresponding to the concentration of the magnetic substance with respect to the input signal (drive signal Ein). As shown in the fourth stage, when the rising edge of the drive coil input signal Ein is input, the phase difference detector 103 starts counting up based on the basic clock Ck. Then, when the rising edge of the output coil output signal Eout is input, the count-up is stopped, and as shown in the fifth stage, the count value is stored as the phase difference data in the storage circuit having the phase difference detector 103. Save temporarily.

1 is an adjuster that adjusts the electromagnetic characteristics of the differential transformer 100, and adjusts the self-inductance of each of the coils 104, 105, and 106 in the differential transformer 100 or the mutual inductance between the coils. As an example of the inductance adjustment method, a movable ferrite core F is provided between the coils, and the mutual inductance is adjusted by adjusting the mutual relationship between the coils 104, 105, 106 and the core F, in this example, the proximity distance. There is a method of adjusting. Or the method of adjusting the self-inductance of each coil by increasing / decreasing the number of windings of each coil is mentioned.
However, the adjustment technique example does not limit the present invention.

  Reference numeral 107 denotes an adjustment controller, which performs an operation based on the control flowchart shown in FIG. In a state where the output coil 106 in the differential transformer 100 is installed at a predetermined magnetic substance concentration N0 (corresponding to the magnetic substance environment in the claims) (see FIG. 4), the adjustment controller 107 is connected to the AC signal generator 101. A coil drive signal Ein having a predetermined electrical characteristic is transmitted (S301). Then, phase difference data T between the coil drive signal Ein and the output signal Eout detected by the phase difference detector 103 is acquired (S302). It is determined whether or not the acquired phase difference data T0 is a predetermined value T0 set in advance. If the phase difference data T0 is different from the predetermined value T0, the electromagnetic characteristics of the differential transformer 100 are adjusted by the adjuster 108. Here, in order to simplify the description, the adjustment reference is set to the predetermined value T0 of the phase difference data. However, in actuality, the determination may be made based on whether or not it is within a predetermined range set in advance.

  FIG. 4 is a characteristic diagram of the phase difference detection data T with respect to the magnetic substance concentration. In the figure, the vertical axis represents the phase difference data T [s] detected by the phase difference detector 103, and the horizontal axis represents the magnetic substance concentration [a. u. : Arbitrary unit]. In the figure, the characteristic B is a reference characteristic in which phase difference data at a predetermined magnetic substance concentration N0 is a predetermined value T0 set in advance. As shown in the characteristics A and C, the actual differential transformer has characteristic variations in each. In this state, according to the present embodiment, the characteristic of the differential transformer 100 having the characteristic A or the characteristic C can be adjusted so as to become the reference characteristic B. In addition, the predetermined magnetic substance concentration N0 should include an environment where no magnetic substance is present.

  In the present embodiment, it has been described that the adjustment method uses a controller that is electrically driven. However, it is also possible to perform adjustment by an operator when manufacturing the apparatus.

  As described above, according to the present embodiment, it is possible to provide a magnetic detection device that can simplify an electric circuit and can greatly reduce the cost and size of the device itself.

  FIG. 5 shows a schematic configuration diagram of a “magnetic detection device” according to the second embodiment. For portions where the reference numerals in FIG. 1 of Example 1 described above overlap, the description of FIG. 1 is used, and the description thereof is omitted here. In FIG. 5, the adjustment controller 107-1 performs an operation based on the control flowchart shown in FIG. In a state where the output coil 106 of the differential transformer 100 is installed at a predetermined magnetic substance concentration N0 (see the description of FIG. 4 described above), the adjustment controller 107-1 receives predetermined electric characteristics from the AC signal generator 101. Is transmitted (S601). Then, phase difference data T between the coil driving signal Ein and the output signal Eout detected by the phase difference detector 103 is acquired (S602). It is determined whether the acquired phase difference data T0 is a predetermined value T0 set in advance. When the value is different from the predetermined value T0, the adjustment controller 107-1 changes the characteristic of the electric signal transmitted from the AC signal generator 101 (corresponding to the predetermined electric characteristic in the claims), for example, the frequency. (S603). Then, using the characteristic data of the electrical signal when the detected phase difference data becomes T0 as the adjustment value of the target magnetic detection device, reference data for actually performing the magnetic detection operation can be obtained. it can.

  Therefore, in the adjustment method of this embodiment, an adjuster for adjusting the electromagnetic characteristics of the differential transformer 100 as shown in FIG. 1 is unnecessary, and the configuration can be simplified.

The “magnetic detection device” according to the third embodiment will be described.
The adjustment method of the magnetic detection apparatus of the present embodiment is a combination of the adjustment methods described in the first and second embodiments.

  Actually, as shown in FIG. 7, the adjustment method described in the first embodiment (corresponding to the first means in the claims) is performed in advance at the stage of manufacturing the magnetic detection device of the present embodiment. Thus, the individual characteristics of the differential transformer are coarsely adjusted (S701). Then, the adjustment method described in the second embodiment (corresponding to the second means in the claims) is executed when the actual magnetic detection operation is performed, thereby finely adjusting the characteristic difference in the installation environment of the apparatus. (S702).

  As described above, according to this embodiment, the detection characteristics can be adjusted more precisely.

Schematic configuration diagram of a magnetic detection device of Example 1 Timing chart showing operation of phase difference detector in magnetic detection apparatus of embodiment 1 Flowchart showing the adjustment method of the magnetic detection device of the first embodiment. The graph which shows the phase difference data with respect to the magnetic body density | concentration of the magnetic detection apparatus of Example 1. Schematic configuration diagram of a magnetic detection device of Example 2 7 is a flowchart showing a method for adjusting the magnetic detection device according to the second embodiment. Flowchart showing the adjustment method of the magnetic detection device of the third embodiment. Specific electric circuit diagram of magnetic detecting device of embodiment Schematic configuration diagram of a conventional magnetic detection device The graph which shows the detection signal voltage characteristic with respect to the magnetic body density | concentration of the conventional magnetic detection apparatus. The graph which shows the adjustment method of the detection signal characteristic with respect to the magnetic substance concentration of the conventional magnetic detection device

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Actuating transformer 101 AC signal generator 103 Phase difference detector 104, 105 Drive coil 106 Output coil 107 Adjustment controller 108 Adjuster

Claims (8)

An output coil that outputs a detection signal corresponding to a magnetic environment, a drive coil differentially connected to the output coil, a transformer having the output coil and the drive coil, and an electromagnetic characteristic of the transformer are adjusted. Adjusting means for applying to the driving coil, AC signal generating means for generating a first AC signal having a predetermined electrical characteristic, and driving the driving coil with the first AC signal to output the output. A phase difference detection means for detecting a phase difference between the second AC signal output from the coil and the first AC signal;
The adjusting means is configured to detect the first alternating current signal and the second alternating current signal detected by the phase difference detecting means in the magnetic environment where the magnetic substance concentration is set to a predetermined value or a predetermined range in advance. A magnetic detection device, wherein the electromagnetic characteristics of the transformer are adjusted so that the phase difference between and a phase difference is a predetermined value set in advance or a phase difference within a predetermined range. The magnetic sensing device according to claim 1,
A magnetic detection device comprising amplification means for amplifying the second AC signal. The magnetic sensing device according to claim 1,
The magnetic detecting device according to claim 1, wherein the adjusting means is means for changing inductance in the transformer. The magnetic sensing device according to claim 1,
The magnetic detecting device according to claim 1, wherein the adjusting means is means for changing an electrical characteristic of the first AC signal. The magnetic sensing device according to claim 4,
The magnetic detection device according to claim 1, wherein the electrical characteristic of the first AC signal is a frequency. An output coil that outputs a detection signal corresponding to a magnetic environment, a drive coil differentially connected to the output coil, a transformer having the output coil and the drive coil, and an electromagnetic characteristic of the transformer are adjusted. Adjusting means to
AC signal generating means for generating a first AC signal having a predetermined electrical characteristic to be applied to the drive coil, and output from the output coil by driving the drive coil with the first AC signal A phase difference detecting means for detecting a phase difference between a second AC signal and the first AC signal,
The adjusting means includes first means for changing inductance in the transformer and second means for changing electrical characteristics of the first AC signal, and a magnetic substance concentration is a predetermined value in advance, or In the magnetic environment set in a predetermined range, a phase difference between the first AC signal and the second AC signal, which is detected by the phase difference detection unit, is set to a predetermined value, or a predetermined value. A magnetic detection device, wherein the electromagnetic characteristics of the transformer are adjusted so as to obtain a phase difference in a range. The magnetic detection device according to claim 6.
A magnetic detection apparatus, wherein the magnetic detection device is adjusted in advance by the first means and adjusted by the second means at the time of magnetic detection. The magnetic detection device according to claim 6 or 7,
The magnetic detection device according to claim 1, wherein the electrical characteristic of the first AC signal is a frequency.

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