JPH0735519A - Method of detecting inferior shape of package - Google Patents

Abstract

PURPOSE:To detect an inferior shape of a package with no aging effect in a detecting system, irrespective of a wind-up position by determining an inferior shape if a measured waveform satisfies any one of conditions when it exceeds a predetermined value at a concave and convex height difference at an end face of the package and a height difference between the end face of the package and an end face of a spool. CONSTITUTION:During measurement of a waveform, the height of the front end 41 of a paper spool 2 is compared with that of a highest part 42 of an end face 1a, and if yMAX (the height of the end face 1a) > B (the height of the front end of a paper spool 2), this package 1 is inferior. Further, during measurement of a waveform, a highest part 43 of the end face 1a is compared with a lowest part 44, and if yMAX-ymin>A (predetermined value), this package is also inferior. On the contrary, during measurement of a waveform, if B>yMAX and yMAX-ymin<A are obtained as the result of the comparison of the front end 45 of the paper spool 2, a highest part 46 and a lowest part 47 of the end face 1a with one another, this package 1 is satisfactory. It is noted that the distance measurement of a sensor 6 has no aging effect since it is irrespective of variation in the light volume of a light source, and accordingly, no variation in waveform occur even though the wind-up position is changed, but only the level thereof varies.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a package shape defect detection method, and more particularly to a package shape defect detection method which is excellent in bulge detection, does not change with time in the detection system, and can be detected regardless of the winding position. It is a thing.

[0002]

2. Description of the Related Art Since a yarn package is formed by winding a yarn around an axis, it has a shape like a column or a truncated cone. Ideally, the end surface is a flat surface. But,
Actually, it is not a perfect flat surface, and some unevenness is formed. If the deformation such as the unevenness becomes large, a problem occurs. Therefore, the quality of the package is determined from the shape of the package, especially the shape of the end surface. As a method for that purpose, a method using an area sensor has been conventionally used. The area sensor has an optical window of a certain size (observation area divided into rectangles), and detects the area occupied by the object in the window by the amount of light obtained from the window. The area sensor is arranged radially outward of the package, the longitudinal direction of the window is set to be parallel to the axis of the package, and the end portion of the package is set to cross the window. Therefore, the package body and the background are projected in the longitudinal direction of the window. If the light source is directed toward the package, only the light reflected from the body will enter the window. From the area of this bright portion, the position of the end portion with respect to the longitudinal direction of the window is detected. And based on the correct end face shape of the package,
It is possible to determine the quality of the end shape by comparing the detection result with the original position of the end.

[0003]

By the way, there is what is called a bulge for the end face deformation. The bulge is a shape with a bulge in the middle of the radius. For example, in the package 1 shown in FIG. 1, the end surface 1a is inside the tip of the paper tube 2 in the vicinity of the paper tube 2, and the end surface 1a protrudes outward at a distance from the paper tube 2, From there, it inclines gently toward the outside of the package.
The bulge 8 is continuously formed in the circumferential direction. Such bulges are likely to appear in synthetic fiber packages. When the bulge becomes large, the top of the bulge may be outside the tip of the paper tube. In this case, the thread on the top comes into direct contact with other objects, and the thread is damaged during storage and transportation of the package. Further, even if the top portion does not extend outside the tip of the paper tube, if the height difference of the bulge becomes large, the problem still occurs.

The above-mentioned conventional methods are vulnerable to bulge detection. This is because the area sensor faces the end of the package from the outside in the radial direction, and therefore the concave portion near the paper tube cannot be seen because it is behind the convex portion.

The conventional method is also weak in step winding. That is, since the area occupied by the package in the window is detected, the same detection result can be obtained regardless of whether the end face has a step or the end face is gently inclined. If a gentle inclination that the height difference is not too large is allowed, it becomes impossible to determine the step winding as defective.

Further, how far the original end without a bulge is located inside the front end of the paper tube (hereinafter referred to as a winding position) is not always constant, but there is some variation. Furthermore, in an inspection machine or the like configured such that the package passes in front of the area sensor, the positional deviation between the package and a holder such as a pedestal that holds the package also causes a positional change of the end portion. However, if the area in the window is detected and compared with the inspection standard like the conventional method, the winding position and
If there is a change in the holding position, etc., the area will be different and correct inspection results cannot be obtained.

Further, as a problem in using the area sensor, there are problems of a change of a light source with time and a depth of focus. The amount of light of a halogen lamp, a fluorescent lamp, etc. used as a light source changes with time. On the other hand, what is detected by the area sensor is the area of the yarn portion based on the reflected light amount of the white background. Since the amount of reflected light on a white background increases or decreases as the light source light amount increases or decreases, an error occurs in area detection. Further, since the package has a cylindrical shape, the distance between the light receiving surface of the area sensor and the edge of the package is not constant, and the area sensor needs to have a deep depth of focus. It is difficult to adjust this depth of focus.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above problems and to provide a package shape defect detection method which is excellent in bulge detection, does not change with time in the detection system, and can be detected regardless of the winding position. .

[0009]

To achieve the above object, the present invention is directed to a package for inspecting a surface of a package, a sensor for measuring a distance by incident / reflecting light, and scanning the package. The quality of the shape is determined.

[0010]

With the above structure, when the surface to be inspected is the end surface, the sensor faces the end surface of the package, so that the optical path is not blocked by the unevenness of the end surface. Therefore, there is no part hidden by the bulge and it can be detected anywhere. This sensor measures the distance between the sensor itself and a portion of the end face of the package that is currently illuminated. Since the measurement of the distance is irrelevant to the fluctuation of the light amount of the light source, a correct detection result can be obtained without being influenced by the temporal change of the light source. When this sensor is scanned in the radial direction of the package or in parallel with it, a measurement waveform that traces the unevenness of the end face is obtained. Even if the winding position is different, the level of the measured waveform changes only and the waveform does not change. The measured waveform shows the unevenness of the end face as it is,
If the front end of the paper tube is also scanned, the height difference between the paper tube and the end face is also expressed. Therefore, based on this, the height difference of the unevenness can be checked and the positional relationship with the paper tube can be checked. In addition, since the measured waveform is faithfully reproduced regardless of whether the unevenness is a step or a gentle slope, these can be distinguished.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

As shown in FIG. 1, the package 1 is
It is composed of a paper tube 2 having a predetermined diameter and a thread Y wound around the paper tube 2, and has a substantially columnar shape. Package 1 is
The paper tube 2 is attached to the pedestal 5 in which the support shaft 4 is erected at the center of the disk 3 by fitting the paper tube 2 into the support shaft 4. The end surface 1a of the package 1 mounted on the pedestal 5 faces upward. Package 1 in this way
Is mounted on the pedestal 5 with the end surface 1a facing upward, and is mounted on a conveyor or the like in an inspection line (not shown) and moved in the direction of the arrow.

The laser sensor 6 is a known distance sensor using laser light, which irradiates the object with the laser light and detects the reflected light thereof to measure the distance by trigonometry. The laser sensor 6 is installed so that the measurement direction thereof faces the end surface 1 a of the package 1. For example, it is attached above the conveyor of the inspection line according to the passage position of the paper tube 2 of the package 1. The locus of the irradiation point of the laser light accompanying the movement of the pedestal 5 is the end surface 1 as shown by the broken line 7.
It overlaps the diameter of a. Moving the pedestal 5 is equivalent to scanning the laser sensor 6.

As shown in FIG. 2, the circuit structure for judgment is roughly divided into a measurement system 21 and a digital processing system 22. The measurement system 21 includes the laser sensor 6, an S / C 23 that performs preprocessing of the signal from the laser sensor 6, and an A / D converter 24 that converts the output of the laser sensor 6 into a digital value. S
/ C23 includes a filter for removing noise components, an amplifier for amplifying the measurement signal, and the like. Digital processing system 22
Is a RAM 25, a CPU 26, a ROM (not shown), I
It is a microcomputer system composed of / O27 and the like.

The processing contents of the digital processing system 22 will be described with reference to FIG. Typical waveforms 31 and 32 obtained in the measurement system 21 by scanning the laser sensor 6 represent changes in the distance between the package 1 and the laser sensor 6, respectively. It represents. Since the locus of the irradiation point of the laser light overlaps the diameter of the end face 1a as shown by the broken line 7, these waveforms correspond to the contour of the cross section along the diameter of the package 1. Therefore, in the following processing, the distance from the laser sensor 6 is converted into height and handled.

For this measured waveform, the digital processing system 22
Has a waveform extracting function and two evaluation items. The evaluation item 1 evaluates whether or not the end surface 1a is swollen from the paper tube 2 by comparing the position of the paper tube 2 and the position of the end surface 1a. A waveform 33 indicating the paper tube 2 is extracted from the measurement waveform 31 of FIG. As shown in FIG. 3A, in the corrugated shape 33 corresponding to the tip of the paper tube 2, two rectangular projections having a relatively narrow width appear along the diameter, and the paper tube 2 is hollow in the middle of these projections. I am greatly depressed. The paper tube 2 can be recognized from this feature. Let B be the height of the tip of the paper tube 2. Waveform 3 showing sharp dips at both ends of package 1
It can be recognized by 4. Between both ends 1b of the package 1,
Moreover, it can be seen that the portion other than the paper tube 2 is the yarn portion, that is, the end surface 1a of the package. Next, the highest value y _MAX of the heights of the end face 1a is extracted. B and y _MAX are compared with each other. If y _MAX is larger, it can be seen that the height of the bulge exceeds the tip of the paper tube 2, and therefore a defective shape is determined. Of course, the determination may be made with a margin with respect to B.

Another evaluation item is to evaluate whether or not the bulge of the end face 1a is acceptable. Similar to the previous item, waveforms 33 and 34 indicating both ends 1b of the paper tube 2 and the package 1 are extracted from the measurement waveform 32 (only the radius is shown) of FIG. 3B. Here, since B> y _MAX , the previous item has passed. This time, the lowest value y _MIN among the heights of the end face 1a is extracted. y
_MAX and y _MIN are compared, and if the difference is larger than the predetermined value A, it is found that the bulge is larger than the permissible size, and therefore a defective shape is determined.

As described above, the content of processing in the digital processing system 22 is to judge whether the shape of the package is good or bad based on the measured waveform, and the result of the judgment is, via the I / O, the higher order which constitutes the inspection line. It is output to an inspection device or the like.

FIG. 4 shows the results of inspecting a number of packages 1 mounted on the pedestal 5 on the inspection line and actually inspecting them. In the measurement waveform of FIG. 4A, the tip 41 of the paper tube 2 and the highest part 4 of the end face 1a are
According to the height comparison with 2, y _MAX > B, so this package is defective. In the measurement waveform of FIG. 4C, by comparing the heights of the highest portion 43 and the lowest portion 44 of the end face 1a, y
_{Since MAX-} y _MIN > A, this package is also defective.

On the other hand, in the measurement waveform of FIG. 4B, B> y _MAX and y _MAX -y are obtained by mutual comparison of the tip 45 of the paper tube 2, the highest portion 46 and the lowest portion 47 of the end face 1a.
This package is good because _MIN <A.

As described above, according to the method of the present invention, since the sensor faces the end surface of the package, the optical path is not obstructed by the unevenness of the end surface. Can be detected. Since the measurement of the distance by this sensor is irrelevant to the fluctuation of the light amount of the light source, a correct detection result can be obtained without being influenced by the temporal change of the light source. The measured waveform obtained by scanning this sensor in the radial direction of the package only changes the level even if the winding position is different, and does not change the waveform. Since the measured waveform represents the unevenness of the end face as it is, it is possible to check the height difference of the unevenness and the positional relationship with the paper tube based on this. In addition, the measured waveform can faithfully reproduce the elevation change of the end face regardless of whether the unevenness is a step or a gentle slope, so that they can be distinguished.

In the present embodiment, the case where the end surface is the inspection target surface has been described, but it goes without saying that another surface may be the inspection target surface.

[0023]

The present invention exhibits the following excellent effects.

(1) It is possible to detect regardless of the shape of the uneven surface and the winding position, and it is excellent in detecting bulges, step windings, fluctuations in the winding position, and the like.

(2) Since it is a shape defect detection method based on distance measurement, it is not affected by the change with time of the light source.

[Brief description of drawings]

FIG. 1 is a perspective view showing a positional relationship between a package and a sensor according to the method of the present invention.

FIG. 2 is a block diagram showing a circuit configuration for determination.

FIG. 3 is a graph showing measured waveforms obtained by a measurement system and extracted values for evaluation.

FIG. 4 is a graph showing measured waveforms obtained from an actual package.

[Explanation of symbols]

 1 Package 6 Sensor (laser sensor) 7 Sensor scanning locus 8 Bulge

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[Procedure amendment]

[Submission date] June 15, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

[0009]

In order to achieve the above-mentioned object, the present invention scans a distance measuring sensor so as to face an end surface of a package, and based on the measured waveform , at least the pattern is measured.
When the unevenness of the package end surface is equal to or larger than the first predetermined value, and
And the difference between the package end surface and the winding tube end surface is equal to or greater than the second predetermined value.
Judged as defective when any one of the above is satisfied
To do .

Claims (1)

[Claims] 1. A shape of a package, characterized in that a sensor for measuring a distance by light reflection / reflection is made to face an inspection target surface of the package for scanning and the quality of the shape of the package is judged based on the measured waveform. Defect detection method.