JPH0145024B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to an appearance inspection device for inspecting the surface of a cylindrical article such as a pharmaceutical capsule.

[Prior art and its problems]

FIG. 1 is an external view of such a drug capsule. That is, the capsule 1 is composed of a cap 11 and a body 12, and the cap 11 is further provided with a locking hole (notch) 13 for locking the cap and the body 12 together. The capsule before being filled with a drug is called an empty capsule, and at this time the bonding force between the cap 11 and the body 12 is small and they are in a so-called temporary bonded state as shown in FIG. After the empty capsule is filled with a drug, the cap 11 and body 12 are further pressed to form a fully bonded state with a strong bonding force, as shown in FIG. Capsules formed in this manner may suffer from various defects during manufacture. For example, a thin spot where the wall thickness of the capsule is partially thinned, a hole where this thin spot becomes even larger,
Examples include pinholes. Among the manufactured capsules, there are loose products in which the cap and body are separated, twin caps in which the separated cap is recombined with the normal product body, and lock capsules in which the empty capsule is fully connected during capsule transportation. There may be cases where defective products called . Therefore, it is necessary to inspect empty capsules and eliminate unnecessary products with the above-mentioned defects.

By the way, such a capsule inspection is performed, for example, as follows.

FIG. 2 is a configuration diagram showing a conventional example of a capsule inspection device, FIG. 2A is an explanatory diagram showing the relationship between the capsule transport mode and the sensor output waveform, and FIG. 3 is an explanatory diagram for explaining the capsule scanning method. be. In FIG. 2, 2 is an optical sensor that irradiates light onto a capsule and receives the reflected light, 3 is an analog/digital (A/D) converter, 4 is a memory, 5 is a digital processing unit (CPU), and 6 is an analog/digital (A/D) converter. is the controller (CTL). Note that the capsule 1 is transferred in the direction of the arrow by the conveying member 7 shown in FIG. 2A, while being rotated about its longitudinal axis as the central rotation axis, so that the capsule 1 is transported in the direction of the arrow by the conveying member 7 shown in FIG. The surface of each capsule will then be scanned.
Such scanning is also called helical scanning,
The output waveform obtained by this helical scan is, for example, an analog waveform as shown in FIG. At step 5, a capsule inspection can be performed by performing predetermined processing based on the data stored in the memory 4.

However, such an inspection device has the following drawbacks.

First, the memory capacity becomes enormous. That is, for example, as shown in Figure 3,
The diameter of the capsule is d _C , the total length of the capsule is L _T , the distance the capsule is transported during one rotation is L _P ,
If the interval for reading digital data from the A/D converter 3 is d _P , the memory capacity C _T required to scan the entire surface is C _T = πd _C・L _T /L _P・1/d _P ...It is expressed as (1). Here, for example, d _C = 7 mm, L _T
If you try to read data at intervals of 0.1 mm in order to inspect a flaw with a hole diameter of 0.5φ occurring in a capsule of = 21 mm, L _P = 0.5 mm and d _P = 0.1 mm, so the above equation (1) is C _T =3.14×7×21/0.5×1/0.1≒10×10 ³ ...(2) Therefore, the required capacity is 10K bytes.

The second problem is that the calculation time becomes longer.
In other words, when attempting to perform various calculations to analyze a waveform using such a large amount of information as described above, the processing time becomes long, making it impractical.

In other words, in the conventional method, the analog signal is stored as is without any processing, which has the disadvantage that not only the memory capacity becomes large, but also the calculation time becomes long.

[Object of the Invention] The present invention has been made in view of the above, and an object thereof is to provide an appearance inspection device that requires less memory capacity and can shorten calculation time.

[Key points of the invention]

The inspection during one revolution of the capsule around its longitudinal axis is performed in real time, and the results are retained for a certain period of time, during which time the data is read into memory, thereby increasing the reading time interval. Sensor output operation that reduces memory capacity and creates a binary signal effective for various inspections by taking into account the speed in the rotational direction of the capsule (peripheral speed) and the speed in the capsule length direction (conveying speed) from the sensor output. By providing a circuit and performing calculations based on the binarized signal from this circuit, the calculation time for binarization by an arithmetic unit is not required and the calculation time is shortened.

[Embodiments of the invention]

FIG. 4 is a configuration diagram showing an embodiment of this invention, and FIG.
The figure is a waveform diagram of each part to explain the operation of Fig. 4,
Figure 6 is an explanatory diagram explaining the memory write (WRITE) and read (READ) operations, Figure 7 is a waveform diagram explaining the timing of reading sensor output into memory, and Figure 8 is the various signals in Figure 7. FIG. 2 is a memory configuration diagram showing a partial storage mode.

In Fig. 4, 21 ₁ and 21 ₂ are differentiators, 22
₁ to 22 ₅ are comparators, 23 ₁ to 23 ₄ are monostable multivibrators, 24 and 26 are bus selection switches, 25 ₁ and 25 ₂ are memories, 27 ₁ and 27 ₂ are data write buses, 27 ₁ ', 27 ₂ ' is a data read bus, 28 is an AND gate, 2, 5, and 6 are sensors and data processing unit (CPU) similar to those in Fig. 2.
and a controller.

Here, the operation will be explained with reference also to FIG. In this case, in the Nth time, the good capsule 1
₁ , and defective capsules 1 _{and 2} with holes 14 are inspected at the N+1 time.

The capsules 1 ₁ and 1 ₂ are helically scanned by the sensor 2, and a signal a as shown in FIG. 5A is obtained. Note that a ₁ is a recess created by the notch 13 , and a ₂ is a recess created by the hole 14 . From this signal a, four types of signals b,
f, g and m are obtained. First, the signal b is obtained by comparing the analog signal a with a predetermined level a _L (FIG. 5A) using the comparator ₂₂₁ ,
As shown in FIG. 5B, the capsule changes depending on the presence or absence of the conveying member 7. The signals f and g are obtained by differentiating the analog signal a by a differentiator 21 ₁ having a predetermined differential coefficient determined by the size of the field of view of the sensor, the capsule transport speed V _T and the shape of the capsule, and then by using the comparators 22 ₂ , 22 ₃ , which is binarized at the levels C _H and C _L shown in Figure 5 C,
Depending on the beginning and end of the capsule storage hole 71 formed in the conveying member ₇ and the beginning and end of the body and cap, the capsules are obtained as shown in FIG. 5 D and H, respectively. Note that these signals f and g are sent to the comparator 22.
₂ , 22 ₃ outputs to monostable multivibrator 23
₁ and 23 ₂ respectively, and the reason for holding the signal for a predetermined time will be described later. On the other hand, signal m
is obtained by differentiating the analog signal a using a differentiator ₂₁₂ having a predetermined differential constant determined by the size of the field of view of the sensor, the circumferential velocity of the capsule _VN , the shape of the defective part, etc. Signal h like h
to a predetermined level using comparators 22 ₄ and 22 ₅ .
By comparing h _H and h _L respectively, the signal i,
The signal k obtained through the monostable multivibrator 23 4 and the signal i obtained through the monostable multivibrator 23 ₄ which shapes the signal j into a signal with a predetermined width are logically ANDed by an AND gate 28 to obtain a signal l, which is further processed by the monostable multivibrator 23 ₃ , the signal is shaped into a signal with a predetermined width. Therefore, the signal l or m is obtained only when a concavity such as _a1 exists in the analog signal a, as shown in FIG. 5G, and is not obtained in other cases.
Here, the concave portion including the notch of the capsule is detected using the monostable multivibrators 23 ₃ and 23 ₄ and the AND gate 28, but the outputs i and j of the comparators 22 ₄ and 22 ₅ are Shape the signal, store it in memory, and send it to the CPU
The detection can be performed within the device 5. The binary signal from the capsule obtained in this way is, for example, from the Nth capsule ₁₁ shown in FIG. Then, those signals are stored in the memory 25 ₁ .
At this time, data regarding the N-1st capsule has been written in the memory ₂₅₂ , so the CPU 5 uses this data to determine the N-1st capsule and sends the result to the controller 6. . Next, N+1 as shown in FIG.
When scanning the second capsule ₁₂ , the controller 6 switches the bus selector switches 24 and 26 to the dotted line positions in FIG. 4, so that the binary signal is written to the memory ₂₅₂ while the memory Since ₂₅₁ is connected to the CPU 5, the CPU 5 judges the Nth capsule.

Here, the timing of writing the binarized signal into the memory will be explained with reference to FIG. 7. In addition,
Figure 7A shows the sensor output a, Figure A' shows its partially enlarged view, Figure 7B shows the output of the AND gate 28 in Figure 4, and Figure 7C shows the monostable multivibrator 23 in Figure 4. Figure ₃ shows the output of 3, and Figure 2 shows the timing pulse t. In particular, the interval between the timing pulses t is a criterion for the determination accuracy in the capsule length direction, but here, for example, if the capsule rotates only 1/4 turn, is chosen equal to the time required to do so. Incidentally, the time width of the binary signal l as described above is determined by the size of the notch or hole in the capsule, but its value is approximately 1/10 or less of the time required for one rotation of the capsule. Therefore, the seventh
Since the signal l cannot be read at the reading timing shown in Figure D, the signal l is read by the monostable multivibrator ₂₃₃ for a period slightly longer than 1/4 period.
The signal m is created by holding only T _H. The signal m can be read more than once as shown in FIG. 7, and the same is true for the signals f and g. In this way, as shown in _{FIG .}
For example, in the case of FIG. 7, the 8th
It is stored as shown in the figure. 6A shows the operation of the memory ₂₅₁ , and FIG. 6B shows the operation of the memory ₂₅₂ , respectively.

Figures 9 and 10 are normal capsules 1 as shown in Figure 5.
FIG. ₁ is an explanatory diagram for explaining the storage mode of signals b, f, g, and m among the signals obtained by scanning the perforated capsules 1 _{and 2} , respectively.

In FIGS. 9 and 10, the symbols shown at each address are attached as follows. That is,
CPIN1 and 2 are the addresses at the beginning and end where the binary signal b becomes "1", RISE1 and 2 are the addresses at which the binary signal f becomes "1", and are at the addresses near the beginning and end of the capsule. CENTER-B,C
is the address near the center of the capsule, FALL1,
2 is the address where the binary signal g becomes "1", and the addresses near the beginning and end of the capsule are
NOTCH1 and 2 are the addresses where the binary signal m becomes "1", and are the addresses that occur in the area where the cap and body overlap, and HOLE is the address mentioned above.
These are assigned in correspondence with the addresses where the binary signal m becomes "1" in areas other than NOTCH. Note that Figure 9 shows the case of a normal product that is transported with the cap first, and Figure 10 shows the case of a defective product that has a hole in the body and is transported with the body first. It can be seen that in FIG. 9, the addresses indicating the notch (NOTCH1, 2) appear earlier than in the case of FIG. 10, and the address indicating the hole (HOLE) does not appear.

Next, a description will be given of how the determination is made based on the information (signals b, f, g, m, etc.) extracted and stored as described above.

Here, the meanings of the signals b, f, g, and m are summarized as follows.

(1) Regarding signal b: Becomes “1” when scanning the capsule or conveyance member.

(2) Regarding the signal f, it becomes "1" when scanning the beginning of the capsule, the end of the capsule storage hole on the transport member, or the cut end of the cap when the capsule is transported with the body first.

(3) About signal g End of capsule, beginning of capsule storage hole,
Alternatively, if the capsule is transported with the cap first and the cap cut end is scanned, it becomes "1".

(4) Signal m becomes "1" when scanning a concave part, a thin part, or a part with low reflectance on the capsule surface.

As described above, each signal has its own meaning, but it is not necessarily determined uniquely, and therefore it is necessary to further analyze these. That is, the signals f and g are generated near the beginning, end, or center of the capsule, but since their addresses are far apart from each other, they can be easily distinguished. However, since there are two types of signal m, one for a notch (NOTCH) and the other for a hole (HOLE), the distinction is made here as follows.

FIG. 11 is a flowchart illustrating a signal determination method.

First, as is clear from the above items (2) and (3), by checking the address where the signal f or g becomes "1", the transport direction of the capsule and the position of the cap cut are determined (○I, (See ○b). Next, check the address where the signal m becomes "1" (see ○C and ○D), and if this address is on the capsule side and is not separated by more than a predetermined distance due to the cap cut, m=
A signal of 1 is due to a notch, whereas a signal that is more than a predetermined distance away and located on the body side can be considered to be due to a hole. Therefore, here, f=1 or g representing the center position.
Determine whether the difference between the address where = 1 and the address where m = 1 is smaller than a predetermined setting value CT1 (see ○, ○), and if YES, it is determined to be due to the notch and normal. (see ○), and if NO, it is determined that the product is defective because it has a hole (see ○). In addition,
In ○C and ○D, if there is no address for which m=1, it is determined as an error (see ○R and ○nu).

The above description has mainly been about inspection of the capsule surface, but it is also possible to inspect twin caps, chipped caps, lock capsules, etc. as described above in the same way. Furthermore, in the embodiment shown in FIG. 4, a monostable multivibrator ₂₃₄ is provided to detect the concave portion of the analog signal.
By connecting this monostable multivibrator 23 ₄ to the 22 ₄ side instead of the comparator 25 ₅ , it is possible to detect the convex portion of the analog signal. Further, if the unevenness of the analog signal is not distinguished, the monostable multivibrator can be omitted. In addition, as mentioned above, the comparator 2
It is also possible to directly store the outputs of 2 ₄ and 22 ₅ and have the CPU 5 perform the detection process.

〔Effect of the invention〕

As described above, according to the present invention, the sensor output is binarized as appropriate to extract various change point signals,
Since this data is sampled and imported sequentially, the interval between data acquisition can be extended.
As a result, the amount of data to be stored in the memory is reduced, which has the advantage that the memory capacity can be reduced and the time required to check the memory contents can be shortened.
In other words, the memory capacity is expressed as in equation (1) above,
At that time, if the total length of the capsule and the distance traveled during one rotation of the capsule are constant, the memory capacity C _T is determined by the data acquisition interval d _P , but here, d _P ≒ πd _C /4. Therefore, C _T = πd _C (L _T /L _P )/(πd _C /4) = 4 (L _T /L _P ), and applying the constant in equation (2) above, C _T = 4 x 21/0.5 = 168, making it possible to reduce the memory capacity to approximately 1/56 compared to the previous model.

Furthermore, since there is no need to binarize the sensor output in the arithmetic device (data processing device), the calculation time can be shortened.

Note that the present invention can be applied not only to drug capsules as described above, but also to general inspection apparatuses for inspecting articles having the same shape as the drug capsules.

[Brief explanation of drawings]

Fig. 1 is an external view showing the capsule, Fig. 2 is a configuration diagram showing a conventional example of a capsule inspection device, Fig. 2A is an explanatory diagram showing the relationship between the transport mode of the capsule and the sensor output waveform, and Fig. 3 is the capsule FIG. 4 is a configuration diagram showing an embodiment of the invention, FIG. 5 is a waveform diagram of each part to explain the operation of FIG. 4, and FIG. 6 is a diagram showing the writing of two memories. , an explanatory diagram for explaining the readout operation, FIG. 7 is a waveform diagram for explaining the relationship between the reading timing of the sensor output into the memory, FIG. 8 is a memory configuration diagram showing the partial storage mode of various signals, and FIG. 9 10 is a memory configuration diagram showing how the various signals shown in FIG. 5 are stored, and FIG. 11 is a flowchart illustrating a signal determination method. Code explanation, 1, _{1 1} , 1 ₂ ...capsule, 11...
...Cap, 12...Body, 13...Notch,
14...hole, 2...optical sensor, 3...A/D converter, 4, 25 ₁ , 25 ₂ ...memory, 5...data processing unit (CPU), 6...controller (CTL), 7 ...Conveyance member, 7 ₁ ...Capsule storage hole of conveyance member, 21 ₁ , 21 ₂ ...Differentiator, 22 ₁
~22 ₅ ... Comparator, 23 ₁ ~23 ₄ ... Monostable multivibrator, 24, 26... Bus selection switch, 27 ₁ , 27 ₂ , 27 ₁ ', 27 ₂ '...
data bus.

Claims (1)

[Scope of Claims] 1. A substantially cylindrical article that is conveyed in the axial direction while being rotated about a longitudinal axis is sequentially scanned by an optical sensor, and a predetermined object is detected according to the outer shape and surface shape of the article. A visual inspection apparatus that inspects an article from a sensor output that changes for each position, and a first system that extracts a signal related to a first change point by binarizing the sensor output at a predetermined threshold level. a first differentiating means for differentiating the sensor output and having a predetermined differential constant that takes into account at least the transport speed of the article;
a second step for extracting signals related to second and third points of change by binarizing the positive and negative signals obtained from the first differentiating means at predetermined levels, respectively;
a third signal extracting means; a second differentiating means for differentiating the sensor output having a predetermined differential constant that takes into account at least the rotational speed of the article; and positive and negative signals obtained from the second differentiating means. and fourth and fifth signal extraction means for extracting signals related to fourth and fifth change points by binarizing at predetermined levels, respectively, and the signals obtained from the first to fifth signal extraction means. 1. An appearance inspection apparatus characterized in that the sample is sampled for each article at predetermined time intervals and stored in a memory, and the inspection is performed by performing predetermined calculations based on the contents. 2. An optical sensor sequentially scans a substantially cylindrical article that is conveyed in the axial direction while being rotated about the longitudinal axis, and changes at predetermined positions according to the outer shape and surface shape of the article. A visual inspection device for inspecting an article based on a sensor output, wherein the sensor output is binarized at a predetermined threshold level to extract a signal related to a first change point thereof; , a first differentiator that differentiates the sensor output and has a predetermined differential constant that takes into account at least the transport speed of the article;
a second step for extracting signals related to second and third points of change by binarizing the positive and negative signals obtained from the first differentiating means at predetermined levels, respectively;
a third signal extracting means; a second differentiating means for differentiating the sensor output having a predetermined differential constant that takes into account at least the rotational speed of the article; and positive and negative signals obtained from the second differentiating means. fourth and fifth signal extraction means for extracting signals related to the fourth and fifth change points by binarizing at predetermined levels, respectively; a signal shaping means for shaping the signal into a signal of Appearance inspection characterized in that the signals obtained from the signal extraction means and the logical product means are sampled for each article at predetermined time intervals, stored in a memory, and the inspection is performed by performing predetermined calculations based on the contents. Device.