JP2869711B2 - Magnetic paint application amount measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a magnetic paint application amount measuring device.

[0002]

2. Description of the Related Art In recent years, in addition to magnetic tapes, magnetic disks, and the like, magnetic recording paper used for tickets, entrance tickets, parking tickets, voting tickets (horse tickets), highway pass tickets, etc., and credit cards The use of magnetic cards used for telephone cards, orange cards, and the like is remarkable. Magnetic recording paper is obtained by applying a magnetic paint to paper or composite paper. On the other hand, the magnetic card is obtained by applying a magnetic paint to a polyester film.

[0003] Whether magnetic recording paper or magnetic card,
Usually, a very thin magnetic layer is formed by preparing a magnetic paint and applying the prepared magnetic paint on a sheet-like base material such as paper or polyester film.
In the present specification, such a sheet-like base material provided with a magnetic layer of a magnetic paint on a base material is referred to as a magnetic sheet. In order to obtain desired magnetic characteristics such as magnetic writing characteristics and magnetic reading characteristics of the magnetic layer of the magnetic sheet, it is necessary to precisely control the amount of the magnetic paint applied on the base material. is there.

Conventionally, as a method for measuring the amount of such a magnetic paint applied, there has been a method using a radiation sensor or a pickup coil. Among the conventional methods of manufacturing this type of magnetic sheet, a conventional method for measuring the amount of applied magnetic paint will be described. As shown schematically in FIG. Sheet 1
, The magnetic paint is first applied onto the sheet base 2A by the coater 3, and the permanent magnet or the electromagnet 4 performs the orientation (magnetization) of the magnetic powder in the applied magnetic paint, Thereafter, the applied magnetic paint is passed through a drying furnace 5 to dry, thereby forming a magnetic layer. The magnetic sheet 2 sent through the drying furnace 5 is taken up as a take-up roll 7. In the conventional measurement method, the application amount detector 6 is arranged between the drying furnace 5 and the take-up roll 7 in close proximity to the magnetic layer of the magnetic sheet 2.

The coating amount detector 6 may use a pickup coil, for example, since the sensor may slightly touch the sheet after drying. The residual magnetism of the magnetic layer is measured via the pickup coil, and the applied amount is indirectly measured assuming that the output is correlated with the applied amount of the magnetic powder. In addition, when using radiation as a non-contact type, there is also a method of indirectly measuring the amount of application from the attenuation of radiation coming through the magnetic layer by using a radiation sensor as the application amount detector 6. .

[0006]

In the conventional pickup coil system described above, if the adhesion between the pickup coil 6 and the magnetic sheet 2 is poor, the detection of the applied amount becomes unstable. Such adhesion is difficult on a magnetic sheet production line.

On the other hand, in the above-mentioned conventional radiation method, a variation in the mixing ratio of the magnetic powder and the binder, the thickness of the raw sheet, and the like cause errors.

An object of the present invention is to provide a magnetic paint application amount measuring device which solves the above-mentioned problems of the prior art.

According to one proposal for achieving the above object, a magnetic paint application amount measuring device for measuring an application amount of a magnetic paint applied on a sheet-like substrate is provided. And a static magnetic field sensor arranged to face the backup surface of the backup with the sheet-like base material interposed therebetween, the static magnetic field sensor comprising: a static magnetic field generating source; A magnetic circuit for passing at least a portion of the magnetic flux from the static magnetic field source through a layer portion of the magnetic paint applied on the sheet-like substrate,
A magnetic sensitive element associated with the magnetic circuit for generating a signal corresponding to a change in magnetic flux passing through the magnetic circuit.

[0010]

According to a first aspect of the present invention, there is provided a magnetic paint application amount measuring apparatus for measuring an application amount of a magnetic paint applied on a sheet-like substrate. Magnetic backup means for supporting a material, static magnetic field sensor means and eddy current sensor means arranged to face the backup surface of the magnetic backup means with the sheet-shaped substrate interposed therebetween, and an output signal of the static magnetic field sensor means And an subtraction unit that outputs a signal corresponding to a difference between the output signal of the eddy current sensor unit and the eddy current sensor unit. The static magnetic field sensor unit and the eddy current sensor unit are held integrally with each other, and The backup means is arranged to sense substantially the same portion on the backup surface.

According to a second feature of the present invention, a magnetic paint application amount measuring device for measuring an application amount of a magnetic paint applied on a sheet-like substrate is provided by a magnetic backup means for supporting the sheet-like substrate. And the static magnetic field sensor means and the eddy current sensor means which are arranged opposite to the backup surface of the magnetic backup means with the sheet-shaped base material interposed therebetween and held integrally with each other; The output of the static magnetic field sensor means and the eddy current sensor means obtained when the static magnetic field sensor means and the eddy current sensor means are scanned along the backup surface of the magnetic backup means in a state where they are not placed. A storage unit for storing a signal, and along a backup surface of the magnetic backup unit in a state where the sheet-shaped substrate is placed. From the difference between the output signal of the static magnetic field sensor and the output signal of the eddy current sensor obtained when the static magnetic field sensor and the eddy current sensor are scanned, the static stored in the storage is stored. Computing means for subtracting the difference between the output signal of the magnetic field sensor means and the output signal of the eddy current sensor means to generate a signal representing the amount of the magnetic paint applied on the sheet-like substrate. Prepare.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a first embodiment of the present invention; FIG.

FIG. 1 shows a schematic configuration of an example of a magnetic paint application amount measuring device according to one proposal for achieving the above object. As schematically shown in FIG. 1, the magnetic paint application amount measuring device of this example applies a magnetic paint on a sheet-like base material 2A such as paper or polyester film, and then drys the magnetic layer 2A.
A non-magnetic backup roll 8 that supports the magnetic sheet 2 having the B formed thereon, and a static magnetic field sensor 9 that is arranged to face the backup surface of the backup roll 8 with the magnetic sheet 2 interposed therebetween. This static magnetic field sensor 9
A permanent magnet 9A as a static magnetic field generating source, and a permanent magnet 9
An inverted U-shaped magnetic core 9B constituting a magnetic circuit for passing a magnetic flux from A, and a Hall element 9 as a magnetic sensitive element
C. Further, an amplifier 9D for amplifying the output signal of the Hall element 9C, and an instruction for receiving the output signal amplified by the amplifier 9D and indicating a measurement value of the amount of magnetic powder contained in the magnetic layer 2B of the magnetic sheet 2 An application amount indicator 9E is provided.

The magnetic core 9B is, as shown in FIG.
A bar-shaped permanent magnet 9A is connected between the substantially middle portions of the two legs, and a hall element 9C is interposed in a yoke portion connecting the two legs, and the open ends of the two legs are supported on the backup surface of the backup roll 8. Magnetic layer 2B of magnetic sheet 2
Is arranged so as to face the vicinity of. Therefore, as shown by the arrow on the magnetic core 9B, a part of the magnetic flux from the permanent magnet 9A passes from one leg of the magnetic core 9B to the magnetic layer 2B of the magnetic sheet 2 and further to the magnetic core 9B. Returning to the other leg of the core 9B, another part of the magnetic flux from the permanent magnet 9A passes from one leg of the magnetic core 9B through the Hall element 9C of the yoke, and
It returns to the other leg of the magnetic core 9B.

According to such a configuration of the static magnetic field sensor 9, when the amount of magnetic powder contained in the magnetic layer 2B of the magnetic sheet 2 supported on the backup surface of the backup roll 8 is large, this magnetic layer The magnetic flux passing through the portion 2B increases, and the magnetic flux to the Hall element 9C decreases. Conversely, when the amount of the magnetic powder contained in the magnetic layer 2B of the magnetic sheet 2 is small, the magnetic flux passing through the magnetic layer 2B decreases, and the magnetic flux to the Hall element 9C increases. Therefore, the output signal of the Hall element 9C changes according to the amount of the magnetic powder contained in the magnetic layer 2B of the magnetic sheet 2 being measured, that is, the applied amount of the magnetic paint. Thus, according to this static magnetic field sensor 9, the output signal from the Hall element 9C is processed by the amplifier 9D,
The indicator 9E can be used to indicate the amount of magnetic paint to be applied.

The apparatus for measuring the amount of applied magnetic paint can measure the applied amount of the magnetic paint on the magnetic sheet without contact and with high sensitivity without using radiation or the like. However, when used in the following environment, the measurement accuracy may not always be sufficient. That is, when the distance between the sensor and the backup roll fluctuates greatly,
For example, when the eccentricity during rotation of the backup roll is large, when the deflection of the magnetic sheet greatly fluctuates, or when the temperature of the supporting structure of the sensor greatly expands and contracts, a measurement error is inevitably generated. Would. Further, when a magnetic material such as a metal roll is used instead of a non-magnetic material for the backup roll, an error due to the inherent magnetic characteristics of the backup roll will inevitably occur.

The present inventor has devised a configuration of a magnetic paint application amount measuring apparatus according to the first feature of the present invention as a device capable of accurately measuring the application amount of magnetic paint even in such a worse environment. . FIG. 2 is a schematic side view showing the configuration of an embodiment of the magnetic paint application amount measuring device according to the first feature of the present invention, and FIG. 3 is a schematic front view thereof. As shown in FIGS. 2 and 3, the magnetic paint application amount measuring apparatus of this embodiment applies a magnetic paint on a sheet-like base material 2A such as paper or polyester film, and then drys the magnetic layer 2A.
A magnetic material backup roll 12 that supports the magnetic sheet 2 on which the B is formed, and a sensor unit 13 that is arranged to face the backup surface of the magnetic material backup roll 12 with the magnetic sheet 2 interposed therebetween. As shown in FIG. 3, the sensor unit 13 includes a static magnetic field sensor 24 and an eddy current sensor 25. The static magnetic field sensor 24 and the eddy current sensor 25 are integrated with each other by a suitable sensor holder. In addition, it is arranged to sense substantially the same portion on the backup surface of the magnetic backup roll 12.

The static magnetic field sensor 24 used here may be any magnetic sensor using a static magnetic field, and may be a magnetic sensor having the same configuration as the static magnetic field sensor 9 described with reference to FIG. The magnetic powder contained in the magnetic layer 2B of the magnetic sheet 2 can be detected. On the other hand, the eddy current sensor 25 is a so-called eddy current type magnetic sensor,
The magnetic powder contained in the magnetic layer 2B of the magnetic sheet 2 is not detected. In the eddy current type magnetic sensor, since no eddy current flows on the magnetic powder side, it does not react to the magnetic powder.
The present invention utilizes the difference in characteristics between the static magnetic field sensor 24 and the eddy current sensor 25 to measure the amount of magnetic powder alone.

That is, the output signal V of the static magnetic field sensor 24
_S is a value corresponding to the sum of the position of the backup surface of the magnetic material backup roll 12 and the amount of the magnetic powder contained in the magnetic layer 2B of the magnetic sheet 2 on the backup surface. sensor 25 of the output signal V _E
Is a value corresponding only to the position of the backup surface of the magnetic backup roll 12. Therefore, the output signal V _S of the static magnetic field sensor 24 and the eddy current sensor 2
By obtaining the difference V _P of the output signal V _E of 5, the amount of magnetic powder contained in the magnetic layer 2B of the magnetic sheet 2, therefore, becomes possible to measure the coating amount of the magnetic coating. Thus, if you adjust the sensitivity to changes of the distance of each sensor to the same, variation V _P by the magnetic powder is obtained by _{V P = V S -V E ····} (1).

According to the configuration of the magnetic paint application amount measuring device according to the first aspect of the present invention, the distance between the sensor and the backup roll fluctuates more than in the device described with reference to FIG. Even in this case, even if the backup roll is a magnetic material, the applied amount of the magnetic paint can be accurately measured. However, in such an apparatus configuration, when the static magnetic field sensor 24 and the eddy current sensor 25 are arranged so as to be able to sense exactly the same point on the backup surface of the magnetic material backup roll 12, a measurement error occurs. In practice, however, both sensors can sense exactly the same point due to the physical positional relationship between the static magnetic field sensor 24 and the eddy current sensor 25 and the difference in the measurement areas between the two. It is difficult to arrange. Therefore,
Even in the configuration of the magnetic paint application amount measuring device according to the first feature of the present invention, a measurement error due to a physical positional relationship between the static magnetic field sensor and the eddy current sensor or a difference in the measurement area between the two is inevitably generated. It is possible that

The inventor has devised a configuration of a magnetic paint application amount measuring apparatus according to the second feature of the present invention, which can correct such a measurement error. FIG. 4 is a schematic front view showing a system configuration of an embodiment of a magnetic paint application amount measuring device according to the second feature of the present invention, and FIG. 5 is a block diagram showing a configuration of a control unit of the system of FIG. It is. As shown in FIG. 4, in the system of this embodiment, the metal backup rolls 12 are horizontally disposed between the support frames 20 on both sides.
Is supported. This metal backup roll
The magnetic backup roll of the apparatus described with reference to FIGS. 2 and 3 may be the same. The linear rails 14 are supported between the support frames 20 at parallel intervals on the metal backup roll 12. The sensor unit 13 is slidably supported on the linear rail 14. This sensor unit 13 may be the same as the sensor unit in the device described with reference to FIGS. The sensor unit 13 integrally holds a static magnetic field sensor 24 and an eddy current sensor 25.

The sensor unit 13 includes a chain wheel 16 driven by a scanning stepping motor 15.
And is moved along the linear rail 14 by the operation of the scanning stepping motor 15. Further, a proximity switch 17 for detecting the origin is arranged near the left chain wheel 16 in FIG. 4, and a scanning limit switch 18 is arranged near both ends of the linear rail 14. Furthermore, the support frame 20
A roll drive motor 10 for driving a metal backup roll 12 and a metal backup roll 1
2 is provided with a roll rotation detecting transducer 1 for detecting the rotational position.

As shown in FIG. 5, the control unit of the system shown in FIG. 4 mainly includes a central processing unit CPU constituted by a microcomputer, a memory 27 for storing various measurement data, and a sensor unit. An operational amplifier 28 for amplifying an output signal from the static magnetic field sensor 24;
An operational amplifier 29 for amplifying an output signal from the eddy current sensor 25 of the sensor unit 13, and an A / D for converting each measurement signal, which is an analog value operated and amplified by each of the operational amplifiers 28 and 29, to digital data. Converters 30 and 31; a stepping motor control circuit 32 for controlling the operation of the scanning stepping motor 15;
7, input / output circuit 33 for scanning limit switch 18 and other control proximity switches (not shown)
And an output circuit 34 for outputting a measurement result to a CRT, a recorder, a printer, or the like.

Next, a description will be given of an operation example of measuring the amount of the magnetic paint applied to the magnetic sheet in the measuring apparatus system having such a configuration.

First, as a measurement preparation operation, the roll drive motor 10 is rotated while the magnetic sheet is not placed on the metal backup roll 12. At this time, the pulse signal from the roll rotation detecting transducer 19 coupled to the backup roll 12 and the signal from the proximity switch 17 for detecting the origin are used.
The central processing unit CPU includes a scanning stepping motor 1.
5 to make the sensor unit 13 come to the origin position. That is, until the sensor unit 13 activates the proximity switch 17 for detecting the origin,
The scanning unit 15 is operated to move the sensor unit 13. Next, from that origin position,
The scanning by the sensor unit 13 is started. This scan is called a reference value storage scan for reading the reference value. Such scanning is performed by the scanning stepping motor 1.
5 and is driven in synchronism with the pulse of the transducer 19 for detecting the rotation of the backup roll 12. That is, the backup surface of the backup roll 12 is spirally scanned, and always scans a fixed path.

Each time the sensor unit 13 scans a fixed distance, the output signal from the static magnetic field sensor 24 is
And digital data stored in the memory 27 via the A / D converter 30 and the eddy current sensor 25
Is stored as digital data in the memory 27 via the operational amplifier 29 and the A / D converter 31. Here, as described with reference to FIGS. 2 and 3, the output signal from the static magnetic field sensor 24 is included in the position of the backup surface of the metal backup roll 12 and the magnetic layer of the magnetic sheet on the backup surface. The output signal from the eddy current sensor 25 has a value related only to the position of the backup surface of the metal backup roll 12. Therefore, in this measurement preparation operation, since nothing is placed on the backup surface of the metal backup roll 12, the output signal from the static magnetic field sensor 24 has a value related only to the position of the backup surface. And it should be substantially the same as the output signal from the eddy current sensor 25.

However, actually, the output signals of the static magnetic field sensor 24 and the eddy current sensor 25 obtained by this measurement preparation operation are not the same. FIG. 6 (A)
FIG. 6 illustrates the level change of the output signal from the static magnetic field sensor 24 obtained by such a reference value storage scan. FIG. 6B shows the eddy current sensor 25 obtained by the same reference value storage scan. 2 illustrates the level change of the output signal due to the above. As can be seen by comparing FIGS. 6A and 6B, each output level fluctuates even though the backup surface is smooth, and furthermore, both output levels fluctuate. not the same. This is the static magnetic field sensor 24
And the eddy current sensor 25 sense a slightly different point on the backup surface, and there is a difference in sensitivity characteristics between the two sensors. It is an inevitable problem. In the device configuration described with reference to FIGS. 2 and 3, it is considered that such a difference between the two appears as an error as it is. Therefore, according to the second feature of the present invention, as a correction value for correcting such an error, the output signal _VSM of the static magnetic field sensor 24 obtained by the reference value storage scan and the eddy current sensor 25 The output signal _VEM is stored in the memory 27.

Next, the measurement scanning is started.
The magnetic sheet to be measured is placed on the metal backup roll 12. Then, the metal backup roll 12
Rotates following the magnetic sheet, and the sensor unit 13 also starts to move in accordance with the movement, and measures the same roll circumference as in the measurement preparation operation in a spiral manner. In this case, the output signal of each sensor differs from that obtained at the time of reference value storage scanning because the magnetic layer on the magnetic sheet on the metal backup roll 12 has a magnetic layer. FIG. 7 (A)
6A corresponds to FIG. 6A, and shows an example of the level change of the output signal V _S of the static magnetic field sensor 24 obtained at the time of measurement scanning. FIG. 7B shows the level change of FIG. ) to which corresponds, are indicative of the levels variations of the output signal V _E of the eddy current sensor 25 obtained during the measurement scan. These output signals V _S
It is _{preferable that} the digital values of V _E and V _E are also stored in the memory 27 once.

These output values V_SAnd V_EWith the aforementioned
(1) Equation V_P= V_S−VE
The amount of magnetic powder contained in the magnetic layer of the
Output V according to the amount of material applied_PIs obtained. But this
Output V_PAs mentioned above,
Error is still included. Therefore, the present invention
According to the second feature of the first embodiment, the central processing unit CPU
Each output signal stored in the memory 27 at the time of storage scanning
Value V_SMAnd V_EMAnd those obtained during the measurement scan
Output signal value V_SAnd V_EAnd the following equation V_P= V_S-V_E−ΔV (2) where ΔV = V_SM-V_EM  Output V according to the actual amount of magnetic paint applied
_PAnd output it through the output circuit 34.
I do. Performing such an operation for each scanning point
The amount of magnetic powder contained in the magnetic layer of the magnetic sheet,
In other words, the amount of magnetic paint applied can be measured accurately without contact.
Can be

[0030]

According to the present invention, accurate measurement can be performed without contacting the magnetic sheet, so that it is simpler and more suitable for use on-line in a magnetic sheet production line than that using radiation. I have.

Since the measurement can be performed accurately without being affected by the change in the distance between the backup surface and the sensor unit, the design conditions of the production line of the magnetic sheet need not be so strict, and the cost of the production line as a whole can be reduced. Can be reduced.

Since the measurement can be performed accurately without contacting the magnetic sheet, it is possible to grasp the amount of the magnetic powder contained in the magnetic layer before applying and drying the magnetic paint on the sheet-like base material.
Since quick adjustment is possible, it is possible to contribute to improvement in the yield of magnetic sheet products.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of an example of a magnetic paint application amount measuring device according to one proposal.

FIG. 2 is a schematic side view showing the configuration of an embodiment of a magnetic paint application amount measuring device according to the first feature of the present invention.

FIG. 3 is a schematic front view of the measuring device of FIG. 2;

FIG. 4 is a schematic front view showing a system configuration of an embodiment of a magnetic paint application amount measuring device according to a second feature of the present invention.

FIG. 5 is a block diagram illustrating a configuration of a control unit of the system in FIG. 4;

6 is a diagram illustrating a level change of output signals of a static magnetic field sensor and an eddy current sensor obtained at the time of reference value storage scanning by the system of FIG. 4;

FIG. 7 is a diagram illustrating a level change of output signals of a static magnetic field sensor and an eddy current sensor obtained at the time of measurement scanning by the system of FIG. 4;

FIG. 8 is a schematic diagram for explaining a conventional method of measuring the amount of applied magnetic paint.

Claims (2)

(57) [Claims] 1. A magnetic paint application amount measuring device for measuring an application amount of a magnetic paint applied on a sheet-like base material, a magnetic backup means for supporting the sheet-like base material, and a backup surface of the magnetic backup means. A static magnetic field sensor and an eddy current sensor disposed opposite to each other with the sheet-shaped base material interposed therebetween, and a difference between an output signal of the static magnetic field sensor and an output signal of the eddy current sensor. A subtraction unit for outputting a signal, wherein the static magnetic field sensor unit and the eddy current sensor unit are held integrally with each other, and substantially the same portion on a backup surface of the magnetic backup unit. A magnetic paint application amount measuring device, which is arranged so as to sense the amount of applied magnetic paint. 2. A magnetic paint application amount measuring device for measuring an application amount of a magnetic paint applied on a sheet-like substrate, wherein a magnetic backup means supporting the sheet-like substrate and a backup surface of the magnetic backup means are provided. With respect to the static magnetic field sensor means and the eddy current sensor means which are arranged to face each other with the sheet-like base material interposed therebetween and held integrally with each other, in a state where the sheet-like base material is not placed,
Storage means for storing output signals of the static magnetic field sensor means and the eddy current sensor means obtained when the static magnetic field sensor means and the eddy current sensor means are scanned along a backup surface of the magnetic backup means. And the static magnetic field sensor obtained when the static magnetic field sensor means and the eddy current sensor means are scanned along the backup surface of the magnetic backup means in a state where the sheet-shaped substrate is placed. Means output signal and
From the difference from the output signal of the eddy current sensor means,
Output signal of the static magnetic field sensor means stored in the
Calculating means for subtracting the difference from the output signal of the eddy current sensor means to generate a signal indicating the application amount of the magnetic paint applied on the sheet-like base material. Paint coating amount measuring device.