JPS62115304A - Joint detector - Google Patents

Abstract

PURPOSE:To detect a joint of material to be processed without being influenced by a disturbance component by providing two optical sensors before and behind and taking an output difference between both sensors. CONSTITUTION:The optical sensors 23A and 23B receive disturbance rays of light by common illuminating lamps 30 and 31 and receive reflected fluorescences from the joint 21b when the joint 21b of the material 21 to be processed comes close to the lower part and the outputs show waveforms (B) and (C) superimposing both voltages. In other words, since the sensors 23A and 23B are arranged before and behind with respect to the feeding direction of the material 21 to be processed, the timing when the joint 21b comes to the lower part is deviated but both voltages by the disturbance rays of light are changed similarly and there is no deviation. Accordingly, when a difference between both is taken with a differential amplifier 24D, there is the component alone by the fluorescence from the joint 21b like figure (D) and the component by the disturbance rays of light is eliminated. Next, when the unnecessary component of output of the amplifier 24D is eliminated through a band-pass filter, the waveform of figure (E) is formed and this is compared with a threshold VTH with a threshold circuit, by which a joint detecting signal like figure (F) can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a seam detection device for detecting seams in cloth.

Conventional fabrics are usually manufactured in lengths of, for example, 50 m, but in some cases, it is advantageous in terms of processing efficiency to process multiple pieces of fabric continuously after the fish carpet process, and when each piece of fabric is There are cases where it is necessary to treat them individually. For example, brushed treatment,
It is more advantageous to perform shearing treatment, 14-mole treatment, etc. continuously by successive pieces of cloth.

However, in each of the above treatments, it may be inconvenient to treat the seam part and the fabric part in the same way, as will be explained later. The method used is to temporarily suspend the process and restart it after passing the seam.

FIG. 7 shows an example of a cloth processing apparatus that uses such a method to raise and shear cloth.

This cloth processing device sends a workpiece L consisting of a plurality of continuous cloths joined by joining threads along a plurality of guide rolls 2 and drive rolls 3, and during the process of moving the workpiece 1, a beater roll 5 , a brush roll 4 is placed behind it, a cutter 6 is placed behind it, the beater roll 5 beats the workpiece 1, and then the brush roll 4 applies a brushing treatment to the workpiece 1. After that, the hair is sheared using a cutter 6 and sent to the next process.

□ The shearing process described above is a process that cuts the hair on the surface of the workpiece 1 to the same length. Therefore, if the seam between the pieces of fabric is sheared in the same way as the fabric, the threads at the seam will break. The pieces of cloth become separated from each other, and the cutter 6
This was inconvenient, as the blades were often worn or damaged.

Therefore, a seam detection device W7 is placed in front of the cutter 6 during the moving process of the workpiece 1, and this seam detection device 7 detects the position of the seam between the pieces of cloth. Based on this detection output, The cutter 6 is separated from the workpiece 1 by a cutter automatic lifting device 8 from the time the joint reaches just before the position of the cutter 6 until it passes, and the shearing process is not performed at the joint part.

9 is a main drive motor that rotates the drive roll; 10 is a pulse generator that detects the rotation speed of the drive roll 3; 11
12 is a motor that drives the brush roll 4, 12 is a motor that drives the beater roll 5, 13 is a cutter drive motor that drives the cutter 6, and 14 is a pulse generator lO.
and the main drive motor 9 based on the output of the seam detection device 7. Motor 11.12. This is a control unit that controls the cutter drive motor i3 and cutter automatic lifting device 8.

As a seam detection device used in the fabric processing device mentioned above, the applicant has already filed an application (Japanese Patent Application No.
No. 194618).

This seam detection device irradiates ultraviolet rays from an ultraviolet lamp such as a black light blue discharge lamp onto a workpiece made by sewing the opposing ends of adjacent fabrics together with fluorescently dyed seaming threads, and then Fluorescence (visible light)
It is configured to detect seams between pieces of cloth by detecting them with an optical sensor.

When using this method of detecting fluorescence from splicing yarns, only the seams of the workpiece are optically detected, so it is unrelated to the color and pattern of the fabric, and since it uses a reflective light reception method, it is This method has the advantage of being able to accurately detect seams without being restricted by the surface structure of the tissue 1.

Hereinafter, this seam detection device will be explained based on FIGS. 8 to 16. As shown in Fig. 8, this seam detection device detects a workpiece 21 in which a plurality of pieces of fabric are successively joined in the longitudinal direction (in the direction of arrow A) using splicing threads that have been given fluorescent properties by fluorescent dyeing or the like. The seam detection device detects the seam 21b, and includes an ultraviolet lamp 22 such as a blank light blue discharge lamp that illuminates at high frequency and irradiates ultraviolet light (indicated by arrow B1) to the workpiece 21 sent in the longitudinal direction; Work material 21
Optical sensor 2 that detects visible light (indicated by arrow B2) from
3, and an amplifier @V52a that amplifies the output of this optical sensor 23.
, a bandpass filter 26 that removes the lighting frequency component of the ultraviolet lamp 22 and a DC component in the output of the amplifier 24, and a threshold circuit 25 that compares the output of the bandpass filter 26 with a threshold value. There is. In this case, the lighting frequency of the ultraviolet lamp 22 is set at the seam 21 of the fluorescence amount signal.
A frequency that is 100 times or more higher than the frequency corresponding to b,
Normally it is set to 41z between 1 and 30.

The bandpass filter 26 includes a low-pass filter 27 that removes the lighting frequency component of the ultraviolet lamp 22 included in the fluorescence amount signal from the optical sensor 23, and a DC component (due to the cloth part 21a emitting fluorescence) included in the fluorescence amount signal. As shown in FIG. 9, the fluorescence from the seam 21b of the fluorescence amount signal is transmitted to the optical sensor
For the frequency f corresponding to the time of incidence on (1/10
) r to 1Of and pass 100% in the frequency range from (1
/100) f or less and 100f or more (7) It has a frequency characteristic that cuts off in the frequency range, and the cutoff frequency of the low-pass filter 27 is set to IOf, and the cutoff frequency of the bypass filter 28 is set to (l/10)r. has been done.

Fig. 10 shows the spectral distribution of each light, curve C1 shows the spectral distribution of the ultraviolet lamp, curve C2 shows the spectral distribution of fluorescence (visible light) emitted from the joining thread, and song 1! I
C:I indicates the sensitivity distribution of the optical sensor 23, νc1 is the center wavelength of ultraviolet light, and νc2 is the center wavelength of fluorescence.

Now, for example, as shown in FIG. 11, the fabric portion 21a of the workpiece 21 moving in the direction of arrow A
When located below the optical sensor 23, the ultraviolet rays from the ultraviolet lamp 22 are simply reflected by the fabric portion 21a and incident on the optical sensor 23. On the other hand, as shown in FIG. 12, the joint 21 of the workpiece 21. When b is located near the bottom of the ultraviolet lamp 22 and the optical sensor 23,
The ultraviolet light from the ultraviolet lamp 22 is reflected at the seam 21b and enters the optical sensor 23, and the fluorescence emitted from the seam 21b also enters the optical sensor 23.

Next, the operation will be explained with reference to FIGS. 13 and 14.

First, as shown in FIG. 13(A), regarding the seam 21b of the workpiece 21 (cross-hatching shows strong fluorescence) made by splicing fabrics without fluorescent characteristics with threads, and the fabric parts 21a on both sides of the seam 21b. Thinking about it, the output of the amplifier 24 that amplifies the fluorescence amount signal that is the output of the optical sensor 23 is the 13th
As shown in Figure (B), the seam 21b is connected to the ultraviolet lamp 2.
2 and near the bottom of the optical sensor 23, the fluorescence from the seam 21b enters the optical sensor 23, and a voltage with a waveform similar to a double-wave rectified waveform of the drive power frequency (for example, 30 kHz) of the ultraviolet lamp 22 appears. become. On the other hand, in the fabric portions 21a on both sides of the seam 21b, no fluorescence occurs, and the output of the amplifier 24 is zero.

When the output of the amplifier 24 is passed through a low-pass filter 27, the lighting frequency component of the ultraviolet lamp 22 is removed.
The waveform becomes as shown in Fig. 3 (C), and when it is further passed through the bypass filter 28, the DC component is removed, resulting in a waveform as shown in Fig. 13 (D), which is compared with the threshold value VTFI by the threshold circuit 25. By doing so, a seam detection signal as shown in Fig. N413 (E) can be obtained.

In addition, as shown in li@14 (A), the workpiece material 21 is made by splicing fabrics with a splicing thread that has a fluorescence characteristic weaker than that of the splicing thread (cross-hatching shows strong fluorescence, hatching shows weak fluorescence). Seam 21b and fabric portions 21a on both sides thereof
Considering this, the output of the amplifier 24 that amplifies the output of the optical sensor 23 is as shown in FIG. The fluorescence from 21b enters the optical sensor 23, and a voltage with a waveform approximating the double-wave rectified waveform of the drive power frequency (for example, 30 kHz) of the ultraviolet lamp 22 appears. On the other hand, in the fabric parts 21b on both sides of the seam 21b, fluorescence is generated, although less than in the part of the seam 21b, and the output of the intensifier 24 has a value corresponding to the amount of fluorescence from the fabric part 21b.

When the output of the amplifier 24 is passed through a low-pass filter 27, the lighting frequency component of the ultraviolet lamp 22 is removed.
The waveform becomes as shown in Fig. 4 (C), and when it is further passed through the bypass filter 28, the DC component is removed, resulting in a waveform as shown in Fig. 14 (CD), which is similar to Fig. 13 (D). By comparing it with the threshold value VTFI at step 25, a seam detection signal as shown in FIG. 14(E) is obtained.

Here, as shown in FIG. 15, the frequency r corresponding to the time when the fluorescence from the seam 21b enters the optical sensor 23 in the fluorescence amount signal is the effective length of the optical sensor 23 e, and the length of the seam 21b. When the feeding speed of the L1 workpiece 21 is V, it is given by f=-J+2L. This formula is derived as follows. That is, as shown in FIG. 15, the fluorescence from the seam 21b is scattered not only when the seam 21b is directly below the optical sensor 23, but also at positions within a range of approximately the length L of the seam 21b before and after the seam 21b. Therefore, the amount of light incident on the optical sensor 23 is the 16th vI! when the seam 21b passes below the optical sensor 23. The level changes as shown in J. Note that FIG. 16 shows an example in which the lighting frequency component of the ultraviolet lamp is not included.

The time T during which the fluorescence from the seam 21b is incident on the optical sensor 23 is expressed as (2), and from this time T, v f --+ Fuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuu t i+2l.

For example, 1=2cm, L-2os, v=18m/min-3
In the case of 0cs/sec, 2+2X2 = 5Hz, l and L are the same as above, and the feed speed V is 9m
/min to 36m/min, the frequency f will be r-2.5Hz to 10Hz, and when f=1011z, the lighting frequency F of the ultraviolet lamp is, for example, 100 times the frequency f, F. =1
0X100 = 1000Hz "1kHz".

Problems to be Solved by the Invention The seam detection device as described above has problems when general illumination light from a fluorescent lamp, mercury lamp, etc. enters the optical sensor 23, or when induced noise enters the output line of the optical sensor 23. , a disturbance signal in the form of a double-wave rectified AC signal of a commercial frequency (50 Hz or 60 Hz) is superimposed on the output of the amplifier 24, and this signal cannot be removed even if it passes through the bandpass filter 26, and the level of this disturbance signal is large. and the seam 21 of the workpiece 21
There is a problem that b cannot be detected.

This will be explained using Fig. 17. For example, Fig. 17 (
As shown in A), the front side of the workpiece 21 (the optical sensor 23
commercial frequency (50 Hz or 6
When illumination lights 30 and 31 that turn on at (Hlz) are arranged, the light from these illumination lights is reflected on the surface of the workpiece 21 as shown by waveform arrows DI and D2, and the light sensor 2
The output of the amplifier 24 that amplifies the fluorescence amount signal which is the output of the optical sensor 23 is the 17th.
As shown in Figure (B), the seam 21b is connected to the ultraviolet lamp 2.
2 and near the bottom of the optical sensor 23, the fluorescence from the seam 21b enters the optical sensor 23, and the disturbance light such as the above-mentioned reflected light and transmitted light enters the optical sensor 23,
A voltage with a waveform appears, which is obtained by superimposing the voltage of the waveform returned to the double-wave rectified waveform of the driving power supply frequency (for example, 30 kHz) of the ultraviolet lamp 22 on the voltage of the double-wave rectified waveform of the AC signal of the commercial frequency.

On the other hand, in the fabric portions 21a on both sides of the seam 21b, no fluorescence occurs, and only the voltage caused by the disturbance light appears as the output of the amplifier 24.

When the output of the amplifier 24 is passed through a low-pass filter 27, the lighting frequency component of the ultraviolet lamp 22 is removed.
The waveform becomes as shown in Fig. 7 (C), and when it is further passed through the bypass filter 28, the DC component is removed, resulting in a waveform as shown in Fig. 17 (D), which is compared with the threshold value VTFI by the threshold circuit 25. As a result, a flat constant level signal unrelated to the position of the seam as shown in FIG. 17(E) is output, resulting in the problem that the seam cannot be detected.

To solve this problem, it is necessary to shield the ultraviolet lamp 22, the optical sensor 23, and their surroundings, but it is extremely difficult to completely shield them.
There was a problem in that the structure became complicated due to shielding.

Furthermore, the above-mentioned drawbacks are caused not only by disturbance light but also by induced noise at commercial frequencies.

An object of the present invention is to provide a seam detection device that has a simple configuration, can eliminate the effects of disturbance light and induced noise from lighting equipment that lights at a commercial frequency, and can reliably detect seams. It is.

Means for Solving the Problems The seam detection device of the present invention is a seam detection device that detects the seams of a workpiece material in which a plurality of pieces of fabric are successively joined in the longitudinal direction using a splicing thread that has fluorescence. an ultraviolet lamp that irradiates ultraviolet rays to the workpiece being fed in the longitudinal direction, and first and second lamps that are arranged in front and behind with respect to the feeding direction of the workpiece and detect visible light from the workpiece. 2 optical sensors, a differential amplifier that detects the difference in output between the first and second optical sensors, and a threshold circuit that compares the output of the differential amplifier with a threshold value. .

According to the configuration of the present invention, a differential amplifier detects the output difference between the first and second optical sensors arranged in front and behind with respect to the feed direction of the workpiece, and the output of the differential amplifier is subjected to signal processing. Therefore, even if a disturbance component may be superimposed on the output of the first and second optical sensors due to disturbance light or induced noise from lighting equipment that lights up at a commercial frequency, this disturbance component will be superimposed on the output of the first and second optical sensors. By taking the difference in the outputs of the two optical sensors, they are canceled out and only the fluorescence component of the seam remains, allowing the seam of the workpiece to be detected without being affected by disturbance components.

Embodiment A first embodiment of the present invention will be described with reference to FIGS. 1 to 4. This seam detection device is shown in Figures 1 and 2.
As shown in the figure, this is a seam detection device that detects the seam of a workpiece 21 in which multiple pieces of fabric are joined in a continuous manner in the longitudinal direction using splicing threads with fluorescent properties. Ultraviolet lamps 22A and 22B irradiate ultraviolet rays (indicated by arrows B1 and B3) to the workpiece 21 that is being processed, and ultraviolet lamps 22A and 22B that are arranged in front and back with respect to the feeding direction of the workpiece 21 (indicated by the arrow). First and second optical sensors 23A, 23B that detect light (indicated by arrows B2 and B4) from the workpiece 21, and a differential sensor that detects the difference in output between the first and second optical sensors 23A, 23B. an amplifier 24D, a bandpass filter 26 that removes the lighting frequency components and DC components of the ultraviolet lamps 22A and 22B from the output of the differential amplifier 24D, and a bandpass filter 26 that compares the output of the bandpass filter 26 with a threshold value. Threshold circuit 2
5.

In this case, the ultraviolet lamps 22A, 22B are arranged so that their tube axes are perpendicular to the feeding direction of the workpiece 21 (direction of arrow A) and lined up in front and back with respect to the feeding direction of the workpiece 21, The optical sensors 23A, 23B are the ultraviolet lamps 22A,
23B is placed between them, and the distance between them is 10 to 2.
01, it faces the workpiece 21 with an interval of 20 to 30w. In FIG. 2, numeral 33 indicates a case in which the ultraviolet lamps 22A, 22B and the optical sensors 23A, 23B are attached.

Furthermore, the lighting frequency of the ultraviolet lamps 22A and 22B is a frequency that is higher than the frequency too(t'N) corresponding to the seam 21b, and is set to about 1 to 30 kllz when energized, but in this example, it is set to, for example, 33 kllz. are doing.

The bandpass filter 26 is composed of a low-pass filter 27 that removes the lighting frequency component of the ultraviolet lamps 22A and 22B, and a bypass filter 28 that removes the DC component (caused by the fabric portion 21a emitting fluorescence).
The fluorescence from the light sensor 23A.

For the frequency f corresponding to the time of incidence on 23B, (1
/10) It has a frequency characteristic of passing 100% in the frequency range from f to lOf and blocking it in the frequency range below (1/100)f and above 1001, and the cutoff frequency of the low-pass filter 27 is set to 10f, The cutoff frequency of the bypass filter 28 is set to (1/10)[1.

Next, as shown in FIG. 3(A), for example, the workpiece 2
Commercial frequency (5011z or 60H) such as fluorescent lamps for general lighting, water viewing lights, etc.
When illuminating lights 30°31 are arranged to light up at z),
The light from these illumination lights 30°31 is shown by the waveform arrow D1. D
The light is reflected from the surface of the workpiece 21 as shown by 2 and is detected by the optical sensor 23'A.

23B, or enters the optical sensors 23A and 23B through the workpiece 2l-ti1.

At this time, the output of the optical sensor 23A is as shown in FIG. 3(B), when the joint 21b is located near the bottom of the ultraviolet lamp 22A and the optical sensor 23A, the fluorescence from the joint 21b enters the optical sensor 23A. At the same time, the disturbance light such as the reflected light and transmitted light enters the optical sensor 23A, and is converted into the voltage of the double-wave rectified waveform of the AC signal of the commercial frequency and the double-wave rectified waveform of the drive power frequency (for example, 30 kHz) of the ultraviolet lamp 22A. A voltage with a waveform obtained by superimposing voltages with approximate waveforms will appear. On the other hand, no fluorescence occurs in the fabric portions 21a on both sides of the seam 21b, and only the voltage due to the disturbance light appears as the output of the optical sensor 23A.

Furthermore, as shown in FIG. 3(C), when the joint 21b is located near the bottom of the ultraviolet lamp 22B and the optical sensor 23B, the output of the optical sensor 23B is determined by the fluorescence from the joint 21b entering the optical sensor 23B. , the disturbance light such as the reflected light and transmitted light enters the optical sensor 23B, and the voltage of the double-wave rectified waveform of the AC signal at the commercial frequency is converted to the ultraviolet lamp 22.
A voltage having a waveform obtained by superimposing a voltage having a waveform approximate to the double-wave rectified waveform of the driving power supply frequency (for example, 30 kHz) of B appears. On the other hand, the fabric portions 21 on both sides of the seam 21b
At point a, no fluorescence occurs, and the output of the optical sensor 23B is only a voltage due to the disturbance light.

However, since the optical sensor 23A and the optical sensor 23B are arranged side by side with respect to the feeding direction of the workpiece 21, the timing at which the seam 21b is located near the bottom is shifted, and on the other hand, the voltage due to the disturbance light is Since both change in the same way, there is no difference.

Therefore, if the difference between the two is taken by the differential amplifier 24D, the output will be only the component due to the fluorescence from the seam 21b as shown in FIG. 3(D), and the component due to the disturbance light will be removed.

When the output of the differential amplifier 24D is passed through the low-pass filter 27, the lighting frequency components of the ultraviolet lamps 22A and 22B are removed, and when it is further passed through the bypass filter 28 to remove the DC component, the output is as shown in FIG. 3(E). By comparing this waveform with the threshold value VTFI in the threshold circuit 25, a seam detection signal as shown in FIG. 3(F) is obtained.

Note that Fig. 7143 shows the waveform when the cloth portion 21a of the workpiece 21 does not emit fluorescence, but even if the cloth portion 21a emits fluorescence, the influence of ambient light will be Removed as above.

According to the configuration of this embodiment, the differential amplifier 24D detects the output difference between the first and second optical sensors 23A and 23B arranged in front and behind with respect to the feeding direction of the workpiece 21,
Since the output of the differential amplifier 24D is subjected to signal processing, disturbance components may be superimposed on the outputs of the first and second optical sensors 23A and 23B due to disturbance light or induced noise from lighting equipment that lights at a commercial frequency. Even if there is, this disturbance component is canceled out by taking the difference in output between the first and second optical sensors 23A and 23B, leaving only the component due to the fluorescence of the seam 21b, without being affected by the disturbance component. The seam 21b of the workpiece 21 can be detected.

In addition, since the seam detection device irradiates the workpiece 21 with ultraviolet rays from the ultraviolet lamps 22A and 22B that are lit at high frequency, the frequency corresponding to the time when the fluorescence from the seam 21b enters the optical sensor 23 in the fluorescence amount signal is The lighting frequencies of the ultraviolet lamps 22A and 22B are sufficiently separated, so that the lighting frequency components of the ultraviolet lamps 22A and 22B included in the fluorescence amount signals output from the optical sensors 23A and 23B can be removed, and the DC component can be removed. After that, by comparing with the threshold value VTFI, even if the fabric part 21a has fluorescent characteristics, the seam 21b and the fabric part 21
If there is a difference in the amount of fluorescence between a and a, the seam 21b can be reliably detected without changing the threshold VTR.

Note that if the sensitivity distribution of the optical sensor 23 is partially different from the spectral distribution of ultraviolet rays, the optical sensors 23A, 23B
If a filter for removing ultraviolet rays is placed in front of the light-receiving section of , components caused by ultraviolet rays will not appear in the outputs of the optical sensors 23A and 23B.

Further, an ultraviolet lamp 22A in the workpiece 21.

22B and the parts facing the optical sensors 23A and 23B shake, the level of the fluorescence amount signal changes due to this shaking, which may cause malfunction. 22B and optical sensor 23A.

It is desirable that the portion facing 23B be moved on something like a flat plate to prevent the workpiece 21 from shaking.

In the above embodiment, the ultraviolet lamps 22A and 22B were provided for the optical sensors 23A and 23B, respectively.
As shown in FIG. 4, one ultraviolet lamp 22 is arranged so that its tube axis is parallel to the feeding direction of the workpiece 21.
A real ultraviolet lamp 22 can also be used for both the optical sensors 23A and 23B.

A second embodiment of the invention will be described based on FIGS. 5 and 6. In this seam detection device, instead of simply detecting the level using the threshold circuit 25 as shown in FIG. 1, sophisticated signal processing is performed using circuit blocks as described below.

That is, by comparing the output of the bypass filter 28 shown in FIG. 6(A) with threshold 1*Vru in the threshold circuit 41, the waveform is shaped to obtain a signal as shown in FIG. 6(C). The signal is used to generate a pulse having a width of time TA as shown in FIG. 6(D) using a timing circuit 42 consisting of a monostable multi-by-break. This time TA is determined by the optical sensor 23A.

23B and the feeding speed of the workpiece 21.

Further, the output of the bypass filter 28 is inverted as shown in FIG. 6(B) by an inverting circuit 43, and the output of this inverting circuit 43 is compared with a threshold value VTR in a threshold circuit 44 to shape the waveform. A signal as shown in FIG. 6(E) is obtained.

Then, the output of the timing circuit 1i@42 and the output of the threshold circuit 44 are added to the AND circuit 45, and the AND circuit 45
The configuration is such that a seam detection signal as shown in FIG. 6(F) is obtained from the above.

The speed converter 46 changes the time TA of the output pulse of the timing circuit 42 according to the feed speed of the workpiece 21. The rest of the structure is the same as that of the second embodiment.

With this configuration, by appropriately setting the time TA of the output pulse of the timing circuit 42, the workpiece 2
The joint 21b of I passes near the bottom of the optical sensor 23A, and then passes near the bottom of the optical sensor 23B, and a positive polarity signal appears in the differential amplifier 24D as shown in FIG. 6 (8). After this, a seam detection signal will be output only if a scratch signal appears within time TA.
It is possible to prevent a seam detection signal from being erroneously output due to power supply noise (single noise) such as a surge.

Other effects are similar to the first implementation (+l+).

In addition, in the above embodiment, in order to be able to detect the seam 21a even when the fabric part 21a of the workpiece 21 emits fluorescence, the ultraviolet lamps 22A and 22B are turned on at high frequency, and the differential intensifier 24D is turned on. Output to bandpass filter 2
Although the signal is processed after passing through the ultraviolet lamp 22A, from the sole purpose of removing the influence of ambient light, the ultraviolet lamp 22A is used.

22B) Ii: It is not necessary to turn on the high frequency and pass the output of the differential amplifier 24D to the 'M-band filter 26. In other words, the ultraviolet lamps 22A, 22B are turned on at a commercial frequency, without passing through the bandpass filter 26.
You can simply process the signal as is.

Furthermore, in the present invention, the term "cloth" refers to something with an elongated shape, and there are no particular limitations on its fiber structure or constituent fibers, such as woven fabrics, knitted fabrics, or non-woven fabrics.

Effects of the Invention According to the seam detection device of the present invention, the output difference between the first and second optical sensors arranged in front and behind with respect to the feed direction of the workpiece is detected by the differential amplifier, and In order to process the output of is canceled out by taking the difference in the outputs of the first and second optical sensors, leaving only the component due to the fluorescence of the seam, so that the seam of the workpiece can be detected without being affected by disturbance components.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the first embodiment of the present invention, FIG. 2 is a schematic diagram showing the same structure, FIG. 3 is an operation explanatory diagram, and FIG.
116 is a schematic diagram showing a modified example, FIG. 5 is a block diagram of the second embodiment of the invention, and FIG. 116 is a waveform diagram showing its operation.
Fig. 7 is a schematic diagram showing a fabric processing device, Fig. 8 is a block diagram of a conventional seam detection device, Fig. 9 is a frequency characteristic diagram of a bandpass filter, and Fig. 1O shows the spectral distribution of ultraviolet rays and fluorescence and an optical sensor. 11 and 12 are schematic diagrams showing the state of light incident on the optical sensor,
13 and 14 are explanatory diagrams of the operation of the seam detection device shown in FIG. 8, FIGS. 15 and 16 are explanatory diagrams of the time during which fluorescence from the seam enters the optical sensor, and FIG. 17 is the diagram of FIG. 8. FIG. 2 is an explanatory diagram of the drawbacks of the seam detection device. 21... Workpiece material, 22A, 22B... Ultraviolet lamp, 23A... First optical sensor, 23B... Second optical sensor, 24D... Differential amplifier, 25... Threshold circuit, 26...Band filter pit Figure 1 Figure 4 □
-ノ -11 Figure 5 Figure 6 Figure 7 Figure 15 Figure 16 Figure 10 Figure 11 (C) Figure 12 Figure 13 Figure 14 Stone (Extrusion□□□□N■■ ＼Ha , & ~ puV ■■ (E) ■ - 'D1! !

Claims (1)

[Scope of Claims] A seam detection device for detecting the seam of a workpiece in which a plurality of pieces of fabric are successively joined in the longitudinal direction using a splicing yarn with fluorescence, the said workpiece being fed in the longitudinal direction. an ultraviolet lamp that irradiates the material with ultraviolet rays, first and second optical sensors that are arranged in front and back with respect to the feeding direction of the workpiece and detect visible light from the workpiece; A seam detection device comprising: a differential amplifier that detects an output difference between second optical sensors; and a threshold circuit that compares the output of the differential amplifier with a threshold.