JP2000097685A - Unevenness detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To permit exact unevenness detection in a short time with no influence of a distance and time changes of a sheet-like measured object transferred in a thickness direction. SOLUTION: The detector device is placed opposed to positions holding a sheet-like measured object 14 transferred along a face direction in a thickness direction, where a pair of elastic bodies 15, 17 that slidably pressure-contact to a corresponding face of the object 14 so as to mutually press contactors 15a, 17a placed at each tip point of the detector device for unevenness detection and a detection means 20 that measures a mutual distance between the tip points of a pair of the elastic bodies 15, 17 to detect a surface unevenness of the object 14 based upon the measurement result are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an unevenness detecting device for detecting unevenness on a surface of a sheet-like measuring object such as a paper sheet.

[0002]

2. Description of the Related Art As is well known, a concavo-convex detecting device as described above conveys an object to be measured in the plane direction by sandwiching paper sheets as objects to be measured from both sides thereof with rollers or belts. The surface irregularities are detected with respect to the paper sheets.

[0003] As this type of unevenness detecting device,
Conventionally, a light beam narrowly squeezed from a light source is applied to the surface of a paper sheet, and the fluctuation of reflected light caused by the unevenness is detected by a light receiving sensor, or a probe is provided at one end, and a probe is provided at the other end. A cantilever with a magnet,
It is swingably supported at the middle part, and detects the vibration of the magnet caused by the movement of the probe applied to the surface of the paper sheet as a change in the current generated in a fixed coil provided opposite to the magnet. Techniques and the like are generally widely used.

However, in the conventional unevenness detecting device using light, when a sheet is conveyed and fluctuates in its thickness direction, the reflected light also fluctuates in the same direction. Fluctuates, and a stable detection result cannot be obtained.

In the conventional unevenness detecting device using a cantilever, the movable range of the cantilever is limited due to the support structure of the cantilever, the detection sensitivity, and the like. However, there is a disadvantage that accurate detection of unevenness cannot be performed.

If the cantilever has a structure in which the movable range is widened, the weight of the movable portion is inevitably increased. Therefore, when the sheet is conveyed at a high speed, the speed of the cantilever swinging in the thickness direction of the sheet is increased. Therefore, it is necessary to run the paper sheet at a low speed, and it takes a long time to detect unevenness.

[0007]

As described above, the conventional unevenness detecting device has a structure capable of sufficiently coping with the magnitude and speed of the shaking occurring in the thickness direction when the sheet-like measured object is conveyed. Therefore, there is a problem that accurate unevenness detection cannot be performed in a short time, which is not suitable for practical use.

Therefore, the present invention has been made in view of the above circumstances, and is accurate in a short time without being affected by a change in distance and time in a thickness direction of a sheet-like measurement object to be conveyed. An object of the present invention is to provide an extremely good unevenness detecting device which can perform unevenness detection.

[0009]

An unevenness detecting device according to the present invention is provided so as to face a sheet-like object to be conveyed along a surface direction at a position sandwiching the object in a thickness direction thereof. A pair of elastic bodies that slidably press the contacts for detecting unevenness provided at the respective tip portions against corresponding surfaces of the object to be pressed against each other, and the tip portions of the pair of elastic bodies; And a detecting means for measuring an interval between the two and detecting irregularities on the surface of the object to be measured based on the measurement result.

According to the above configuration, even if the object to be measured is displaced in the thickness direction at the time of transportation, the pair of elastic bodies are deformed so as to sufficiently follow the displacement, and the tip of the pair of elastic bodies is deformed. Since the interval between the parts is not changed, accurate concavo-convex detection can be performed in a short time without being affected by changes in the distance and time in the thickness direction of the conveyed sheet-like measurement object. It becomes possible.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. First, FIG. 1 shows the overall configuration of the unevenness detecting device 11 described in this embodiment. The unevenness detecting device 11 is provided with a pair of transport rollers 12a and 12b whose peripheral sides are in contact with each other and separated by a predetermined distance from the pair of transport rollers 12a and 12b. And a pair of transport rollers 13a and 13b.

Then, a sheet-like measuring object 1 such as a sheet of paper 1
When inserted into an object-to-be-measured object insertion opening (not shown) of the unevenness detecting device 11, both surfaces thereof are transport rollers 12a and 12b.
The sheet is successively sandwiched between the transfer rollers 13a and 13b, and is transferred in a direction indicated by an arrow A in FIG.

As will be described later in detail, between the transport rollers 12a and 12b and the transport rollers 13a and 13b, there are provided an uneven body composed of an elastic body 15 and its support portion 16, and an elastic body 17 and its support portion 18. The detection unit 19 is interposed.
Then, while the device under test 14 is being conveyed between the conveying rollers 12a and 12b and the conveying rollers 13a and 13b, the unevenness on the surface is detected by the unevenness detecting unit 19.

The other transporting means includes a portion between the transport rollers 12a and 13a and a portion between the transport rollers 12b and 13b.
, Two narrow belts (not shown) are respectively wound in parallel at a predetermined interval, and both ends of the four narrow belts in the direction orthogonal to the transport direction of the DUT 14 are interposed between the two belts. A configuration in which the object 14 is conveyed while holding the unit is also considered. In this configuration, the unevenness detection unit 19 is interposed between two belts arranged in a direction orthogonal to the transport direction of the measured object 14, and detects the unevenness on the surface of the measured object 14. .

In this case, the unevenness detecting section 19 detects the object 1 to be measured.
4 generates electrical detection signals corresponding to the irregularities on the surface. The detection signal is supplied to the unevenness detection circuit 20 and subjected to predetermined signal processing, thereby extracting the signal as an unevenness detection signal in a desired form. For example, a host computer 21 provided outside the unevenness detection device 11 And so on.

FIG. 2 shows a detailed configuration of the unevenness detecting section 19. That is, the elastic body 15 is formed in an elongated belt shape, and one end of the elastic body 15 is fixed to the support section 16 and arranged on one surface side of the DUT 14. In addition, the elastic body 17 is also formed in an elongated band shape,
One end of the DUT 1 is fixed to the support 18.
4 is disposed on the other surface side.

Further, the elastic members 15 and 17 are provided such that the other ends thereof are slidably pressed against one and the other surfaces of the DUT 14 via the contacts 15a and 17a. . That is, when there is no DUT 14, the contacts 15 a and 17 a are in contact with each other so as to press each other due to the urging force of the elastic bodies 15 and 17.

When the object 14 moves in the direction of arrow A and enters between the contacts 15a, 17a, the elastic body 1
Due to the elastic force of 5, 17, the contact 15a moves in the direction of arrow B,
The contact 17a is pushed and spread in the direction of arrow C and comes into pressure contact with each surface of the DUT 14.

The elastic body 15 has a structure in which elastic films 15c and 15d such as polyimide films are attached to both surfaces of an adhesive body 15b such as a double-sided adhesive tape. Similarly, the other elastic body 17 also has a structure in which elastic films 17c and 17d such as a polyimide film are adhered to both surfaces of an adhesive body 17b such as a double-sided adhesive tape.

As shown in FIG. 3, the elastic film 15c constituting the surface of the elastic body 15 opposite to the surface on which the contact 15a is attached is located at a position corresponding to the contact 15a as shown in FIG. A detection coil 22 is provided.

As shown in FIGS. 4 and 5, the detection coil 22 has a print coil 22a formed by spirally printing a conductive print wire on one side of an elastic film 15c, and a print coil 22a. And a print coil 22c formed by spirally printing a conductive print wire on the other surface of the elastic film 15c in the same winding direction as the print coil 22a. , This print coil 2
A land 22d to which one end of 2c is connected is formed, and the other ends of the print coils 22a and 22c are connected to each other via a through-hole conductor 22e penetrating the elastic film 15c.

As shown in FIGS. 2 and 3, when one end of the elastic body 15 is supported by the support portion 16, the lands 22b and 22d formed on the elastic film 15c are formed.
Are connected to a terminal line 23, and the detection coil 22 is connected to the unevenness detection circuit 20 via the terminal line 23.

The detection coil 24 is also formed on the elastic film 17c constituting the elastic body 17 as shown in FIG. 2, but the structure is the same as that of the detection coil 22. Omitted. The detection coil 24 is also connected to the unevenness detection circuit 20 via a terminal wire 25.

Here, the contacts 15a and 17a are each formed of a wear-resistant material so that the contacts 15a and 17a do not come into contact with the object 14 to be conveyed and are not worn. In this case, as shown in FIGS. 6A and 6B, the contact 15a is brought into line contact with one surface of the DUT 14 with a slight length in a direction orthogonal to the transport direction. Ridge line 15e
It has a shape having.

The contact 17a is formed as shown in FIG.
As shown in (b), the surface of the device under test 14 has a planar portion 17e that is in surface contact with a predetermined area.

According to the contacts 15a and 17a having such a shape, as shown in FIG. 8, when the DUT 14 is sandwiched, the ridge 15e of the contact 15a is formed on one surface of the DUT 14. It will penetrate deeply into the gap of the formed unevenness. For this reason, when the object to be measured 14 travels in the direction of arrow A, the contacts 15a, 1
The interval between 7a is changed.

FIG. 9 shows details of the unevenness detecting circuit 20. In FIG. 9, reference numeral 26 denotes a bridge circuit. The bridge circuit 26 includes two fixed resistors R1,
R2, a detection coil 27 formed by connecting the detection coils 22 and 24 in series, and, similarly to the detection coils 22 and 24, two print coils as shown in FIG. Dummy coil 2 formed by connecting two sets of coils D1 and D2 facing each other with
And 8.

The bridge circuit 26 is adjusted to be in a balanced state by a balance adjusting resistor (not shown) for adjusting a difference in impedance between the detection coil 27 and the dummy coil 28.

Here, the bridge circuit 26 is energized by applying an AC voltage output from an AC oscillation circuit 29. Then, a voltage obtained by dividing the output AC voltage of the AC oscillation circuit 29 by the fixed resistor R1 and the detection coil 27 and a voltage obtained by dividing the output AC voltage by the fixed resistor R2 and the dummy coil 28 are respectively represented by a differential amplifier circuit. 30. The output of the differential amplifier circuit 30 is supplied to a synchronous detection circuit 31
Is supplied to

The AC voltage output from the AC oscillation circuit 29 is supplied to a phase setting circuit 32. The phase setting circuit 31 converts the input AC voltage into a desired set phase and outputs the converted voltage to the synchronous detection circuit 31. Thus, the synchronous detection circuit 31 can detect and rectify the output of the differential amplifier circuit 30 under a highly sensitive phase condition.

The output of the synchronous detection circuit 31 is a BPF
(Band Pass Filter) are supplied to the amplifier circuit 33 and the filter amplifier circuit 34, respectively. Among them, the BPF amplifier circuit 33 selects and amplifies a signal of a specific frequency from the signals detected and rectified by the synchronous detection circuit 31. Then, the output signal of the synchronous detection circuit 31 is
After the rectification is performed and the ripples are smoothed by the filter circuit 36, they are taken out from the output terminal 37.

The filter amplifying circuit 34 smoothes and amplifies the ripple of the signal detected and rectified by the synchronous detection circuit 31, and outputs the signal from an output terminal 38. The signal obtained from the output terminal 38 corresponds to the thickness of the device under test 14.

According to the unevenness detecting device configured as described above, first, when there is no object 14 to be measured, the contacts 15a and 17a are in contact with each other so as to press each other. In this state, when the DUT 14 is conveyed in the direction of arrow A in FIG. 2 and enters between the contacts 15a and 17a, the contact 15a is in the direction of arrow B and the contact 17a is in the direction of arrow C.
In the direction, the distance between the detection coils 22 and 24 increases.

When the distance between the detection coils 22 and 24 changes as described above, the coupling impedance of the detection coils 22 and 24 changes, so that the balance of the bridge circuit 26 is lost and the output AC voltage of the differential amplifier circuit 30 changes. , The output of the synchronous detection circuit 31 changes. For this reason, if the surface of the device under test 14 has irregularities with a constant period, if the center frequency of the BPF amplifier circuit 33 is adjusted to the period of the irregularities, the signal of the irregular period can be easily extracted, Rectifier circuit 35
And a filter circuit 36 to obtain a DC signal.

Here, when the tip of the DUT 14 enters between the contacts 15a and 17a, or when the contact 15
When the rear end of the device under test 14 is pulled out from between the points a and 17a, the contacts 15a and 17a vibrate while the distance between them suddenly changes. In order to suppress this vibration, the elastic bodies 15 and 17 are replaced with an adhesive 15b such as a double-sided adhesive tape.
Elastic films 15c, 15d and 17 are provided on both sides of 17b.
(c) and (17d) are adhered, and the adhesive bodies (15b, 17)
The buffering action is provided by the viscosity of b.

Next, a case where the object 14 is displaced in its thickness direction, that is, in the direction of arrow B or C in FIG. 2 will be described. First, when the object 14 is displaced in the direction of arrow B, the elastic body 15 is pressed and deformed by the object 14 and the elastic body 17 is deformed in the direction of arrow B following the object 14 by its restoring force. In order to perform the operation, the two detection coils 22 and 2
4 will not change.

Also, when the object 14 is displaced in the direction of arrow C, the elastic body 17 is pressed and deformed by the object 14 and the elastic body 15 is deformed by the restoring force.
Is deformed in the direction of arrow C, so that the distance between the two detection coils 22 and 24 does not change.

As described above, since the distance between the two detection coils 22 and 24 does not change with respect to the displacement of the measured object 14 in the thickness direction, a stable and accurate detection signal can be always obtained. Become. In addition, since the elastic members 15 and 17 use a tape-shaped adhesive, an elastic film, and a print coil as their constituent elements, respectively, they can be reduced in size and weight, and the thickness of the DUT 14 can be sharply increased. It is possible to sufficiently follow a large change and a large fluctuation in the thickness direction.

FIGS. 10A, 10B, and 10C show output waveforms of the filter amplifier circuit 34, the BPF amplifier circuit 33, and the filter circuit 36 in FIG. 9, respectively. These waveforms show that a paper piece having a thickness of 80 μm has a running speed of 6 μm.
The sheet was conveyed at a speed of 00 mm / s, and irregularities on the surface were detected.

The waveform shown in FIG. 10A corresponds to the thickness of the paper sheet, and points A to D indicate the length of the paper sheet. In addition, this piece of paper has a height of 5 to 10 μm and a width of 50 to 60 μm between point B and point C of the waveform shown in FIG.
The irregularities are formed at a period of m and a pitch of 0.15 to 0.2 mm.

The waveform shown in FIG. 10A clearly shows the change in the thickness of the paper piece with good followability. The waveform shown in FIG. 3B is the output of the BPF amplifier circuit 33 whose center frequency is set to 3 kHz, and the amplitude is large in response to the unevenness formed between the points B and C of the paper sheet. Has become.

Further, the waveform shown in FIG.
The output of the amplifying circuit 33, that is, the waveform shown in FIG. 3B is rectified and smoothed, and the output voltage is obtained at a high frequency of 3 kHz signal in the uneven area from the point B to the point C of the sheet. The level is higher.

By performing the signal processing in accordance with the pitch frequency of the irregularities on the surface of the device under test 14, irregularities can be detected with high sensitivity. When a plurality of uneven areas having different pitch frequencies are present on the surface of the device under test 14, a BPF amplifier circuit 33 having a center frequency corresponding to each of the uneven areas is prepared. You just have to use it.

Further, such an unevenness detecting device 11 is
If a plurality of objects are installed in the width direction of the object 14, that is, in the direction orthogonal to the transport direction, the distribution of unevenness over the entire surface of the object 14 can be detected.

In the above-described embodiment, the ridge 15e is formed on one of the contacts 15a so as to make line contact with the surface of the DUT 14, and the other contact 17a is formed with the ridge 15e.
The flat part 17e is formed so as to be in surface contact with the surface of the object 14; however, if the contact 17a is also formed with a ridge line that is in line contact with the surface of the object 14, the both sides of the object 14 can be formed. Can be detected at the same time.

As the contacts 15a and 17a, not only the shape of line contact and surface contact with the DUT 14 by the ridge line portion 15e and the flat surface portion 17e, but also the point contact by a sharp tip or the spherical or curved surface. It goes without saying that various shapes and combinations, such as shapes that can make contact, can be considered. It should be noted that the present invention is not limited to the above-described embodiment, and can be variously modified and implemented without departing from the scope of the invention.

[0047]

As described in detail above, according to the present invention,
Provided is an extremely good unevenness detecting device which can accurately detect unevenness in a short time without being affected by a change in distance and time in a thickness direction of a conveyed sheet-like measurement object. Can be.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of an unevenness detecting device according to the present invention.

FIG. 2 is a side view showing details of an unevenness detecting unit in the embodiment.

FIG. 3 is a plan view showing details of an unevenness detection unit in the embodiment.

FIG. 4 is a plan view showing details of a detection coil in the embodiment.

FIG. 5 is a side view showing details of the detection coil in the embodiment.

FIG. 6 is a diagram showing details of one contact in the embodiment.

FIG. 7 is a view showing details of the other contact in the embodiment.

FIG. 8 is a side view showing a relationship between each contact and an object to be measured in the embodiment.

FIG. 9 is a block diagram showing details of an unevenness detection circuit according to the embodiment;

FIG. 10 is a diagram showing operation waveforms of each part of the unevenness detection circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Unevenness detection apparatus, 12a, 12b ... Conveyance roller, 13a, 13b ... Conveyance roller, 14 ... Measurement object, 15 ... Elastic body, 16 ... Support part, 17 ... Elastic body, 18 ... Support part, 19 ... Unevenness detection Reference numeral 20: unevenness detection circuit, 21: host computer, 22: detection coil, 23: terminal wire, 24: detection coil, 25: terminal wire, 26: bridge circuit, 27: detection coil, 28: dummy coil, 29 ... AC oscillation circuit, 30 differential amplifier circuit, 31 synchronous detection circuit, 32 phase setting circuit, 33 BPF amplifier circuit, 34 filter amplifier circuit, 35 rectifier circuit, 36 filter circuit, 37, 38 output Terminal.

Claims (8)

[Claims] 1. A sheet-like object to be measured conveyed along a plane direction, which is installed to face a position sandwiching the sheet-like object in a thickness direction thereof. And a pair of elastic bodies which slidably press against the corresponding surface of the object to be measured so as to press each other, and a distance between the distal ends of the pair of elastic bodies is measured. Detecting means for detecting unevenness on the surface of the object to be measured based on the detected unevenness. 2. The device according to claim 1, wherein one of the contacts for detecting unevenness provided at the distal ends of the pair of elastic bodies has a shape that makes linear contact with the surface of the object to be measured. Unevenness detection device. 3. The device according to claim 1, wherein one of the contacts for detecting unevenness provided at the distal ends of the pair of elastic bodies has a shape that makes point contact with the surface of the object to be measured. Unevenness detection device. 4. The device according to claim 2, wherein the other of the concavo-convex detecting contacts provided at the distal ends of the pair of elastic bodies has a shape that makes surface contact with the surface of the object to be measured. The unevenness detecting device according to the above. 5. The unevenness detecting device according to claim 1, wherein the elastic body has a structure in which a plurality of substantially elastic films formed in a belt shape are bonded with an adhesive. 6. The detection means includes detection coils provided at the distal ends of the pair of elastic bodies, detection signal generation means for obtaining a detection signal corresponding to a change in the coupling impedance of the detection coils, and a detection signal. 2. The unevenness detecting device according to claim 1, further comprising: a filter means for extracting a predetermined frequency band component from the detection signal generated by the generation means, rectifying the frequency component, and smoothing. 7. The elastic body has a structure in which a plurality of substantially elastic films formed in a belt shape are adhered to each other with an adhesive, and the detection coil is provided on one of the plurality of elastic films constituting the elastic body. The unevenness detecting device according to claim 6, wherein the unevenness detecting device is formed. 8. A device according to claim 1, further comprising means for detecting an object having surface irregularities having a predetermined pitch frequency based on the surface irregularities detected by said detecting means. 2. The unevenness detecting device according to 1.