JPS59227621A - Appearance inspecting device - Google Patents

Abstract

PURPOSE:To inspect a cylindrical object with high accuracy by judging the transporting direction of said cylindrical object and generating the optimum mask signal. CONSTITUTION:An optical sensor 3 scans a nearly cylindrical object 1 being transported in its axial direction while being rotated with its longitudinal axis as a rotary axis, while, on the other hand, binarization means 133, 134 binarize the output from the sensor 3 at a certain threshold level. Furthermore, signal extracting means 152, 153 extract position signals which are always emitted from the binarized signals at a certain position of the object 1, while a mask signal generating means 162 generates certain mask signals in accordance with said position signals. That is, by masking position signals which are generated in mutually different positions depending on the difference in transporting direction of the object 1 by means of said mask signals, and by discriminating said position signals from signals generated by a defect of another cause, the inspection of the object 1 is carried out. Thereby, defects such as flaws, etc. can be accurately detected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] This invention relates to an appearance inspection device that inspects a substantially cylindrical article such as a drug capsule based on sensor output obtained by scanning the article with an optical sensor. .

[Prior art and its problems]

Inspection of such articles is generally carried out as follows.

FIG. 1(A) is a schematic diagram illustrating the method for scanning articles;
Figure (B) is an external view showing the appearance of the capsule, Figure 1 (C)
-(F) are waveform diagrams showing the sensor output when scanning the capsule.

That is, the cylindrical article 1 is illuminated by the illuminator 2122, and the reflected light from the article 1 is transmitted to the optical sensor 3.
detected by. The article 1 is placed on a conveyance device (not shown) and conveyed in the direction of the arrow while being rotated by a predetermined means with its longitudinal axis as the rotation axis.
The article 1 will be scanned in a spiral manner by the sensor f3 (helical scan). Here, let us consider a case where a drug capsule 1 as shown in FIG. 1(B) is helically scanned. By the way, the capsule 1 is composed of a cap 11 and a body 12 as shown in the figure, and the cap 11 is further provided with a lock hole (notch) 13 for locking the cap and the body 12 together. In addition,
The capsule 1 shown in the figure is a so-called empty capsule before being filled with a drug, and at this time, the bonding force between the cap 11 and the body 12 is small, and the cap 11 and the body 12 are in a temporarily bonded state by the notch 13. When the capsule 1 configured in this way is helically scanned, the optical sensor 3 detects the following:
An output having a shape as shown in FIG. 1(C) is obtained. In other words, since the cap 11 has a higher reflectance than the body 12, a step occurs in its output waveform, as shown by @ in the figure. Therefore, Ok in the same figure (D)
As shown in the figure, for example, if there is a hole or other flaw in a part of the body, the reflectance of light will be low in this part, that is, a recess will be formed as shown in the figure ('F), so it is difficult to detect the flaw by this K. can. In addition, (E) and (F) in the same figure are θ in (D).
, O is an enlarged waveform diagram showing an enlarged portion. Incidentally, at the boundary (step) between the cap and the body of the capsule, indicated by θ in the same figure (D), a concave portion appears in the waveform as shown in the same figure (E), but this does not indicate an abnormality in the capsule. Therefore, it is necessary to prevent this from being detected as a flaw. Therefore, a position sensor is provided to detect such a stepped portion, and a mask signal is generated in synchronization with the position sensor signal to prevent a flaw signal from being generated in this portion.

FIG. 2 is a waveform diagram illustrating the timing of generation of the mask signal. In the figure, (a) is the above-mentioned position sensor signal, and (b) is a mask signal. Also, (c), (
(d) is the sensor output signal, (c) shows the case where the cap part is carried first, and (d) shows the case where the body part is carried first.

In other words, the direction in which the capsules are conveyed is not necessarily determined; some capsules are conveyed with the cap first, while others are conveyed with the body first. In this case, there is no particular problem as long as the stepped portion is located approximately at the center of the capsule in the longitudinal direction, as shown in FIG.

If there is a difference in the center position as shown in (d), there is a problem in that the width of the mask signal must be widened as shown in (e) of the same figure. In addition, a timing shift as shown by the dotted line occurs in the position sensor signal shown in (a) of the same figure, and (g) for the signal (c) and (g) for the signal (2). If each mask signal deviates as shown in FIG.

A mask signal is a signal that does not see four parts of the signal within the time or interval determined by its width, so the wide signal width means that the signal that should be detected is also overlooked. This means that the detection accuracy will be reduced accordingly.

[Purpose of the invention]

The present invention was made under these circumstances, and aims to provide an appearance inspection device that can accurately detect defects such as scratches by generating an optimal mask signal that takes into consideration the shape of the object to be inspected. Purpose and −ζ.

It is something to do.

[Key points of the invention]

The key point is to determine the conveyance direction of the object to be inspected by examining multiple feature points in the sensor output waveform, determine the inspection area for inspecting flaws, etc. based on the results of this discrimination, and The point is that we have made it possible to carry out inspections such as the following.

[Embodiments of the invention]

FIG. 3 is a configuration diagram showing an embodiment of the present invention, and FIGS. 4 to 6 are waveform diagrams of various parts for explaining the operation of FIG. 3. Third
In the figure, 4 is a position sensor, 11 is an amplifier, 121
122 is a differential circuit, 131 to 134 are comparators, 1
4 is a timer, 151 to 154 are AND gates, 161
162 is a mask signal generation circuit, 17 is a transport direction determining circuit, 18 is a storage circuit, and the other parts are the same as in FIG.

First, its operation will be explained with reference to FIGS. 3 and 4. The cylindrical article is a capsule as shown in FIG. 1(B), and the same applies hereinafter.

The reflected light from the capsule 16 that is irradiated by the illuminators 21 and 22 is converted into an electrical signal by the optical sensor 3. As mentioned above, the capsule 1 is conveyed in the axial direction while being rotated about the longitudinal axis as the rotation axis.
From the sensor 3, an output as shown by ■ in FIG. 4(a) is obtained. In addition, Figure 4 (B) is similar to Figure 1 (E) and (F).
FIG. 3 is a partially enlarged waveform diagram similar to that shown in FIG. The output signal (■) from the sensor 3 is amplified by the amplifier 11 and differentiated by the differentiating circuit 121 for the purpose of detecting flaws, so that the output has a waveform as shown by (■) in Figure 4 (C). can get. The positive part of the differential signal ■ is compared with the predetermined levels THI and TH2 by the comparator 132 and the negative part by the comparator 131, respectively, and outputs ■ and ■ as shown in FIG. 4 (E) and (D) are obtained. It will be done. Furthermore, this signal (ψ
is applied to a timer circuit 14 such as a monostable multivibrator, so that the output 0 shown in FIG. 4 is obtained from the timer 14. This signal (■) and the signal (■) obtained from the converter 132 are connected to the AND gate 151.
The logical product is calculated in , and from the output, [
A signal indicated by "Yes" is output. Note that this signal (2) is stored in the storage circuit 18 in synchronization with the clock pulse.

Next, the explanation of the operation will be continued with reference to FIGS. 3 and 5.

On the other hand, the signal amplified by the amplifier 11 is differentiated by a differentiating circuit 122 for the purpose of determining the transport direction of the capsule, and from its output, a signal as shown in FIG.
is obtained, and when the positive part is compared with the predetermined levels T:H3 and TH4 by the comparator 134 and the negative part by the comparator 133, respectively, the fifth
Figure (to).

Signals like (e) [present] and ■ are obtained. At this time, the position sensor 4 has already outputted the position sensor signal ■ as shown in FIG. A mask signal (2) such as (0) is generated. Therefore, the signals (1) and (2) obtained as described above are respectively applied to the AND gate 15315z, and the output thereof is shown in FIG. 5 (H).

Signals θ and (2) as shown in (G) are obtained. Note that this is a case where the capsule is scanned with its cap side first, but the case where the capsule is scanned with its body side first can also be considered in the same manner as above.

That is, the output ■ of the sensor 3 in this case is shown in Fig. 5 (c).
', and the output ■ obtained by differentiating this with the differentiating circuit 122 is as shown in (d)' in the same figure. Comparators 133 and 134 compare this with a predetermined level to obtain the signals ■ and ■. are as shown in (e)′ and (f)′ in the same figure, respectively. Therefore, the signal ■.

By taking the AND of [Present] and the signal [Present], the same figure (
))'.

Signals (2) and (e) such as (H)' can be obtained. In other words, if the capsule is transported with the cap first, only the signal θ will be "1" as shown in Figure (H), and if the capsule is transported with the body first, the signal will be as shown in Figure (G)'. Since only ① is @1'', it is possible to know the conveyance direction of the capsule from this.

Next, the flaw determination operation will be described with reference to FIGS. 3 and 6.

As described above, when either the output obtained from the AND gate 152 or 1539-, that is, the signal ■ or θ becomes 11'', the transport direction determining circuit 17 detects this and sends the signal to the mask signal generating circuit 162. Since the mask signal generation circuit 162 gives a signal to that effect, the mask signal generation circuit 162 generates a signal as shown in FIG.
Generates a signal such as ■. In other words, if the capsule is transported with the cap first as shown in Figure (A), a signal as shown in Figure (B) will be sent, and if the capsule is transported with the body first as shown in Figure (A)'. output signals as shown in (b)' in the same figure. At this time, the memory circuit 18 is
.

A signal Q1 generated at the stepped portion as shown in (c)' and a signal Q2 generated by the flaw F (see Figures 6(a) and (a)') are stored, but at the stepped portion Since the generated signal Q1 is masked by the Yask signal (2), it is output from the AND gate 154 as shown in FIG.

(d) As shown in '(only the signal 2 due to the flaw F is extracted).

〔Effect of the invention〕

As described above, according to the present invention, an accurate mask signal can be generated by determining the conveyance direction of the cylindrical article -10=, so the area for detecting flaws is expanded, and therefore the accuracy is This has the advantage of making it possible to perform high quality inspections.

In addition, since it is possible to determine the conveyance direction, it is possible to set a flaw inspection area accordingly, and the flaw detection sensitivity can be changed depending on the inspection area.
More accurate detection becomes possible.

Note that the present invention can be applied to general inspection apparatuses for inspecting the appearance of articles similar to drug capsules as described above.

[Brief explanation of the drawing]

Figure 1 (A) is a schematic diagram showing the scanning method of the inspection article;
Figure (B) is an external view showing the drug capsule, Figure 1 (C) -
(F) is a waveform diagram showing the sensor output, FIG. 2 is a waveform diagram explaining the generation timing of the mask signal, FIG. 3 is a configuration diagram showing an embodiment of the present invention, and FIGS. FIG. 3 is a waveform diagram of each part for explaining the operation shown in the figure. Code explanation 1... Cylindrical article (drug capsule), 2122
......-Illuminator, 3...-Optical sensor, 4...
...Position sensor, 11...Amplifier, 121
122...Differential circuit, 131-134...-
... Comparator, 14 ... Timer circuit, 15
1-154...and gate, 161 162
--- Mask signal generation circuit, 17 --- Conveyance direction discrimination circuit, 18 --- Memory circuit Agent Patent attorney Akio Namiki Attorney Patent attorney Kiyoshi Matsuzaki Figure 1 (A ) (B) ■ ■ (E) (F) Fig. 2 - 111 Timing"'s 3rd ffi Gu O - η HA" + l F Fig. 4 (=) ■ -']'] -1 111111ro (ho) ■
-1111-R--- Item 111---11---
---Ding 1----(hen ■-1"]"]1-------
---Ding 1--)-)■----Stone-JL-f positive-- e O■ ○ e [Yes] ■ To ■
2 to 'w o, +l
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Claims (1)

[Claims] An optical sensor that scans a substantially cylindrical article that is conveyed in the axial direction while being rotated about a longitudinal axis, and 2 that binarizes the sensor output at a predetermined threshold level.
digitization means, signal extraction means for extracting a position signal always emitted at a predetermined position of the article from the binary signal, and mask signal generation means for generating a predetermined mask signal in accordance with the nuclear position signal. By masking the position signals generated at different positions due to the difference in the transport direction of the article with the mask signal, it is possible to separately inspect the article by distinguishing the position signal from a signal generated due to a defect. Characteristic appearance inspection equipment.