JP2758550B2 - Appearance inspection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a visual inspection apparatus for detecting deformation of a product group (hereinafter referred to as an inspection object) flowing on a line, and particularly relates to medicines, foods such as tablets and capsules, foods, and the like.
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a visual inspection apparatus suitable for detecting a curved defect at both ends of a test object having both curved surfaces at the both ends of a mechanical component, an electronic component, and the like, particularly, a deformation defect existing at the tip.

[0002]

2. Description of the Related Art A visual inspection apparatus for detecting deformation of an inspection object flowing on a line is disclosed in Japanese Patent Application Laid-Open No. 61-2112.
Various publications have been proposed, including Japanese Patent Laid-Open Publication No. 09-09.
Among them, a visual inspection apparatus particularly for a capsule-shaped inspection object having curved surfaces at both ends is disclosed in
There is one disclosed in Japanese Patent Application Laid-Open No. 5-131756.

The configuration of such a visual inspection apparatus will be described with reference to FIG. FIG. 4 is an explanatory view of a main part of an inspection mechanism described in Japanese Patent Application Laid-Open No. 55-131756. First, the inspection object (40) is transported in the direction of the arrow. (41
Reference numerals a) and 41b denote optical sensors each including at least two light sources and a light receiving element. The optical sensors (41a) and (41b) are respectively +
They are arranged so as to be inclined by θ and −θ and to be opposed to the curved surfaces at both ends of the inspection object. Note that the black dots (42a) (4
2b) shows a scratch or a swine spot (a thin portion just before the hole).

In such an apparatus, an optical sensor (4
1a) When irradiating the inspection object (40) in (41b), the intensity of light reflected from a normal portion of the inspection object (40) and the light reflection state such as a scratch on a curved surface and a swine spot are different from those of a normal portion. Differences occur in the reflected light intensity from different parts. Therefore, the defect can be recognized by detecting the difference in the reflected light intensity. In addition, it is possible to detect a defect existing on the curved surface at both ends of the inspection object by tilting at least two optical sensors (41a) and (41b) with respect to the vertical direction so as to face each other. Has become.

[0005]

However, when an attempt is made to detect a deformation defect existing at the end of a curved surface at both ends using the visual inspection device, the deformation defect is located at a blind spot for the optical sensor. There was a problem that sufficient reflected light could not be obtained from the defect, and a visual inspection based on a change in the amount of light could not be performed. In addition, when inspecting a dark color inspection object, there is a problem that a sufficient change in the amount of light cannot be obtained in the first place, and an appearance inspection becomes impossible.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a blind spot of an object to be inspected by a conventional optical sensor, for example, a deformation defect existing at the tip of a curved end surface of a capsule shape. It is an object of the present invention to provide a visual inspection device capable of detecting the same without depending on the color of the inspection object.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a transfer device for transferring an inspection object on an inspection line and an optical sensor for detecting the presence of deformation existing in a wide area of the inspection object. in the testing apparatus having a displacement sensor can be set to any part on the measurement spot the inspection line, the distance de between the measuring spot and the displacement sensor
Detecting means for detecting deformation of the inspection object based on a change in the sign of the second-order difference result of the data, determining means for determining a defective product by a logical sum of a detection result by the optical sensor and a detection result by the displacement sensor; The gist is that it is provided.

[0008]

According to the present invention, in addition to the conventional optical sensor inspection, an inspection using a displacement sensor is performed. If a deformation defect is present in the inspection object, a change in distance due to the deformation defect is detected and a response is made. Output a signal. That is, when looking at the time change of the output signal of the displacement sensor, the signal is similar to the external shape of the inspection object, and if there is a deformation defect at the end of the curved surface at both ends of the inspection object, the signal changes to the time change of the output signal. Also, a similar change occurs in the deformation defect.
Therefore, the deformation of the inspection object can be detected by detecting a sudden change in the output signal.

However, since the measurement point of the displacement sensor is limited to a relatively small portion, the measurement point is set at a portion which is a blind spot in the inspection by the conventional optical sensor, and the two measurement results are complemented with each other. For this reason, in the present apparatus, the final judgment is made based on the logical sum of the measurement result as described above and the conventional measurement result by the optical sensor.

[0010]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view of the vicinity of the displacement sensor and the detecting means of the present invention. In the figure, a pharmaceutical capsule (hereinafter referred to as a capsule) (1) as an inspection object is placed on a transport device (2) and transported in the direction of an arrow to form an inspection line (L). Thus, the inspection line (L)
On top, two displacement sensors (3a) having the same function
(3b) is provided at an angle (θ) with respect to the vertical direction of the inspection line (L) so that the measurement spot (P) is opposed to the curved surface at both ends of the capsule, and the measurement spot (P) is the tip of the curved surface. (Θ) is +60 in this embodiment.
Degrees and -60 degrees. Further, the displacement sensors (3a) and (3b) use the capsule (1) for measuring spot light.
The mounting mechanism has fine adjustment means such as height, angle, etc., so that the light is projected onto the ends of the curved surfaces at both ends of the lens.

The displacement sensor (3a) used in this embodiment
(3b) is the capsule (1) and the displacement sensors (3a) (3)
b) and outputs an analog signal proportional to the measured distance. Although various types of displacement sensors are known, for example, a displacement sensor that can measure with a resolution of about several μm using laser light without being affected by the light reflection state of the capsule is preferable.

Reference numeral (4) denotes detecting means for detecting the deformation of the inspection object from the outputs of the displacement sensors (3a) and (3b). In this embodiment, the detecting means comprises the following three types. That is, (5) is the displacement sensor (3a) (3b)
A / D conversion means for converting an analog signal output from the A / D into a digital signal, (6) a feature extraction means for extracting a feature of the signal output from the A / D conversion means (5), (7) Is a judging means for judging the presence or absence of a deformation defect of the capsule on the basis of the signal output from the feature extracting means (6), and the displacement sensors (3a) and (3b)
Are processed respectively and the judgment signal (8) corresponding to each signal is processed.
a) Output (8b).

The details of the detection means will be described below. FIG. 2 is an explanatory diagram showing an output signal when the displacement sensors (3c) and (3d) measure the capsules (1c) and (1d) being transferred in the direction of the arrow. In the figure, (a) shows the time change of the output signal when the capsule (1c) having no deformation defect is measured. The output signal has a shape similar to one curved surface of the capsule (1c), and is uniformly convex downward. (B) is a time change of the output signal when the capsule (1d) having the deformation defect (21) at the tip of one curved surface is measured, and the output signal (22) corresponding to the deformation defect portion is displayed above. Appearing in a convex shape. The analog signal is input to the A / D conversion means (5) and is converted into a digital signal. This is because the process for extracting the features can be easily performed by converting into a digital signal.

Next, the digital signal is input to the feature extracting means (6). In the feature extracting means (6), the A
After using the adjacent data of the digital signal from the / D conversion means (5) or data separated by several points from the input signal and applying a second-order difference to the input signal, +1 is output if the result is positive, and -1 if the result is negative. I do. FIG. 2C shows the result of performing the processing on the signal shown in FIG. Since the signal corresponding to one curved surface of the capsule is uniformly convex downward, the calculation result of that portion is uniformly +1. FIG. 2D shows the result of performing the processing on the signal shown in FIG. 2B. In a signal corresponding to one curved surface of the capsule, an upwardly convex portion and a downwardly convex portion are mixed, and +1 and -1 are mixed in the calculation result of the portion. In this manner, by referring to the result of the feature extracting means (6), it is possible to recognize a feature such as whether the time change of the signal is convex upward or downward.

In the above description, the feature extracting means (6)
Refers only to the sign of the second-order difference result, outputs +1 if the result is positive, and outputs -1 if the result is negative. At this time, the value of the second-order difference result is also referred to at the same time. May output 0, thereby ignoring small signal changes and preventing erroneous determination by the determination means (7) later.

Next, the operation result of the feature extracting means (6) is inputted to the judging means (7) to judge the presence or absence of a deformed defect. In other words, a signal corresponding to one curved surface of the capsule (1) is used, and the operation result of the feature extracting means (6) is-
In the case where the area 1 exists, the area has a deformation defect (2).
1) is determined. If the signal corresponding to one curved surface of the capsule (1) and the calculation result of the feature extracting means (6) is uniformly +1, it is determined that no deformation defect exists in that area. Inspection of the other curved surface is similarly performed using the displacement sensor (3b), and based on those results, it can be determined whether or not a deformation defect exists at the tip of the curved surface at both ends of the capsule.

The above configuration is added to a known inspection device having a transport device for transferring an inspection object and an optical sensor for detecting deformation of the inspection object. explain. The portion described in, for example, JP-A-61-21209 can be used. FIG. 3 is a schematic front view of the known inspection apparatus. Capsules (1) to be inspected stored in the hopper (31) are taken out little by little by a vibrating feeder (32) or the like and are aligned in a row by a rectifying mechanism using a rotary table (33) having a rectifying plate or the like. Then, it is sent out to a first conveyor (35) which is an inspection line by a belt conveyor (34).

In this inspection apparatus, an inspection line is formed by a first transport device (35) and a second transport device (36), and a plurality of optical inspection devices (T1) (T2) using a television camera or the like. Using the (T3) and (T4), the first transport device (35) uses the lower surface of the inspection object, the second transport device (3).
In 6), the appearance is inspected from the upper surface direction of the inspection object. As a result of these inspections, a defective product in which an abnormality is found is removed from the non-defective product line by a sorting device (37) using a blower or the like. Here, the aforementioned displacement sensor (3a)
(3b) is installed at an appropriate location of the first transport device (35) or the second transport device (36). At this time, as described above, it is necessary to provide an adjusting means so that the measurement spot can be set at an arbitrary portion on the inspection line.

Now, since the measurement spots of the displacement sensors (3a) and (3b) are relatively small, if the position of the inspection object (1) conveyed on the inspection line oscillates right and left with respect to the inspection line, it will be accurate. Optical inspection equipment (T1) (T2)
(T3) Inspection of the blind spot part of (T4) cannot be performed. Therefore, it is preferable that the first transport device (35) and the second transport device (36) have the following structures.

FIG. 5 is a vertical sectional side view of the transfer device.
In the figure, (51a) and (51b) are a pair of slit plates fixed to face each other in the horizontal direction to form a slit (52), and (53a) and (53b) are endless round belts, and the end of the slit plate. It travels along the guide rail formed on the edge, and the return path is made by slit plates (51a) (5).
It passes through an air box (54) formed in the lower part of 1b).

In such an apparatus, the air box (5
4) When the inside is sucked, the outside air is sucked from the slit (52) and the inspection object (1) is sucked by the endless round belts (53a) and (53b) to drive the endless round belts (53a) and (53b). Thus, the suction conveyance is performed.

At the time of the suction, the test object (1) moves along the endless round belts (53a) and (53b), and the centering is naturally performed. This is particularly noticeable in the case of a curved surface. Therefore, the inspection object (1) is always sucked and transferred to a predetermined position on the inspection line.

Lastly, a description will be given of the point that the final determination is made based on the inspection results by the displacement sensors (3a) (3b) and the optical inspection devices (T1) (T2) (T3) (T4). In this apparatus, the logical sum of both inspection results, that is, if either result is bad, the final judgment result is determined to be bad. Therefore, a discriminating means may be provided corresponding to each test result, and may be operated independently. However, in this case, since a plurality of sorting devices (37) and the like are required, when a single sorting device (37) is used in common, signals are adjusted by timing means for adjusting a time difference between the two inspection signals. It is good to synchronize and then take the logical sum of both signals.

[0024]

According to the present invention, a deformed defect existing at a blind spot of an optical inspection apparatus, for example, at the tip of a curved surface at both ends of a capsule-shaped inspection object is detected without being influenced by the color of the inspection object. This makes it possible to significantly improve the accuracy of the conventional inspection apparatus.

[Brief description of the drawings]

FIG. 1 is a schematic view of the vicinity of a displacement sensor and detection means according to the present invention.

FIG. 2 is an explanatory diagram showing an output signal of a displacement sensor.

FIG. 3 is a schematic front view of a known inspection device.

FIG. 4 is an explanatory diagram of a main part of an optical inspection device.

FIG. 5 is a vertical sectional side view of a transfer device that can be used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inspection object 2 Conveyance device 3a, b Displacement sensor 4 Detection means 5 A / D conversion means 6 Feature extraction means 7 Judgment means 8a, b Judgment signal L Inspection line P Measurement spot 21 Deformation defect on inspection object 22 Deformation defect Sensor output signal corresponding to the section

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) G01B 11/00-11/30 G01N 21/84-21/91

Claims (1)

(57) [Claims] 1. An inspection apparatus comprising: a transport device for transferring an inspection object on an inspection line; and an optical sensor for detecting the presence of a deformation existing in a wide area of the inspection object.
Displacement sensor capable of setting a measurement spot at an arbitrary portion on the inspection line, detecting means for detecting deformation of the inspection object by changing a sign of a second-order difference result of distance data between the measurement spot and the displacement sensor A visual inspection apparatus provided with a discriminating means for discriminating a defective product by a logical sum of a detection result by the optical sensor and a detection result by the displacement sensor.