JPH0136576B2 - - Google Patents

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a cylindrical object having a transparent part and an opaque part, such as a pharmaceutical capsule, which has a body made of a transparent material and a cap made of an opaque material. This relates to a defect detection circuit for objects that inspects defects (scratches, small holes, etc.) by irradiating light onto the surface of the object and performing helical scanning using a photoelectric sensor.

[Conventional technology]

FIG. 1 is a front view showing the entire general capsule appearance inspection apparatus, and FIG. 2 is a side view of the same.

In FIGS. 1 and 2, the main body of the apparatus is indicated by 10, and a hopper 12 into which a capsule to be inspected is placed is attached to the main body. From the hopper 12, the capsules are loaded into a supply chamber 14, within which they are supplied to a transport drum 16. The surfaces of the capsules that are aligned and individually conveyed by the conveyance drum 16 are inspected by an optical inspection device 18, and the detection output of the inspection device 18 is sent to a judgment control section 20 to determine whether the products are good or defective. be done. Then, the capsules that have been inspected are sent to a non-defective ejection chute 2 or a defective ejection chute 24 depending on whether they are good or defective.
The structure is such that the waste is classified and discharged.

FIG. 3 shows the structure of the conveying drum portion of the apparatus main body 10 that conveys the capsules, and in FIG. 3, the same parts as those in FIG. 1 are given the same reference numerals. In FIG. 3, the transport drum 16
is formed into a hollow cylindrical shape, and is rotated in the clockwise direction of the arrow by being driven by a suitable rotational drive mechanism. On the circumferential surface of the conveyance drum 16, through holes 42 are formed at equal intervals in the circumferential direction to accommodate the capsules 40 individually, with the longitudinal direction of the capsules 40 coinciding with the rotational direction of the drum 16. This through hole 4
2 are formed in two rows on the circumference of the drum. The supply chamber 14 temporarily holds the capsules 40 and reliably supplies the capsules into the through holes 42 of the transport drum 16. A brush 15 is attached to return capsules in a bad posture to the supply chamber 14. Conveyance drum 16
The capsule 40 accommodated in the through hole 42 is supported on its lower surface by a guide plate 44.
It is conveyed while sliding on 4. The end surface of the guide plate 44 facing the rotating roller 48 is
The capsule is shaped to match the circumferential surface of the rotating roller 48 so that the capsule can move smoothly onto the rotating roller 18.

The rotating roller 48 has its rotation axis aligned with the conveying drum 1.
6 substantially coincides with the longitudinal axis of the capsule 40, that is, with the capsule conveyance direction. An optical inspection device for inspecting the surface of the capsule rotating in contact with the rotating roller 48 includes a lamp 5 for illumination.
8 and a condensing lens 60 that irradiates the light from the lamp 58 as an intense spot light onto a part of the capsule surface, and a magnifying lens 62 to detect a specified area of the capsule surface, such as the diameter.
Only the light reflected from a specific part of 0.5mm is detected by the photoelectric sensor 6.
4, and a light sensor system configured such that the light is incident on the light beam. A photodiode is used as the photoelectric sensor 64.

The capsules inspected in the optical inspection section are transported to the discharge section. The discharge section includes a defective product discharge nozzle 68 and a non-defective product discharge nozzle 66 that inject air from the inside to the outside of the conveyance drum 16, a defective product discharge chute 22, and a non-defective product discharge chute 24. The jet air from the defective product discharge nozzle 68 and the good product discharge nozzle 66 is configured to hit the capsule through holes 70 and 72 of the guide plate 46.

The present invention relates to a defect detection circuit for a cylindrical object such as a capsule suitable for use in the above-mentioned capsule visual inspection apparatus, and more specifically, to a defect detection circuit for a cylindrical object such as a capsule, which is suitable for use in the capsule visual inspection apparatus as described above. In other words, the present invention relates to a defect detection circuit on the surface of a capsule in which a portion of the capsule is transparent and the rest is opaque, rather than the entire capsule being made of a transparent or opaque material.

Now, consider a case where a small hole 2a exists as a defect in the opaque body 1a, as shown in FIG. 4a. When light is irradiated at this time, the output of the photoelectric sensor 64 is large because sufficient reflected light is obtained in places other than the hole, but at the hole 2a, the amount of light reflected decreases and the output of the photoelectric sensor 64 is small. Become. On the other hand, as shown in FIG. 4b, a transparent body 1b is irradiated with light.
Similarly, if a hole 2b exists as a defective portion, light will be diffusely reflected around the hole 2b, and the output of the photoelectric sensor 64 will be larger than at a location other than the hole.

Therefore, defects in opaque objects are detected by detecting points where the output of the charging sensor becomes smaller than before (fall detection), and defects in transparent objects are detected by detecting points where the output of the photoelectric sensor becomes larger than before. Perform detection (rising edge detection). In this way, the principle of defect detection is different for opaque body parts and transparent body parts, so conventionally, dedicated defect detection circuits were provided separately for each, and the photoelectric sensor was used to determine whether the opaque body part was being scanned or the transparent body part was being scanned. Therefore, it was necessary to detect whether the defect detection circuit was defective or not, and to switch the defect detection circuit to be used accordingly.

FIG. 5 is a perspective view showing how a cylindrical object is scanned by a photoelectric sensor, and FIG. 6 is an output waveform diagram of the photoelectric sensor in FIG.

In FIG. 5, numeral 3 is a cylindrical object schematically showing a capsule, and the first half consists of an opaque part 1b and the second half consists of a transparent part 1b along the traveling direction shown by arrow 5.
It consists of a. Since the rotating body 3 is advanced while rotating, the surface of the rotating body is detected by the photoelectric sensor 64.
Helical scan can be performed by Note that 58 is an illumination lamp.

The output waveform of such a photoelectric sensor 64 is shown in FIG. This waveform diagram consists of a waveform obtained by scanning the opaque area and a waveform obtained by scanning the transparent area, and 2a' and 2b' are flaw signals caused by defects, respectively. Flaw signal 2 in opaque area
As explained with reference to FIG. 4a, a' is a falling signal, and the flaw signal 2b' in the transparent part is a rising signal, as explained with reference to FIG. 4b. will be recognized. Note that, when the cylindrical object 3 is a capsule, the h portion represents halation that occurs when the rounded tip of the capsule strongly reflects light, but this is not directly related to the present invention.

The photoelectric sensor output is input to a first defect detection circuit that detects the falling signal 2a' and a second defect detection circuit (both not shown) that detects the rising signal 2b'. A signal indicating the period during which the advancing cylinder 3 should be scanned by the photoelectric sensor 64 is transmitted to the position sensor of the cylinder 3 (for example, a position sensor located near the drum 16 in FIG. As shown in FIG. 6, a position sensor output is obtained from a sensor (not shown) which detects the rotational position of 16 and thereby detects the position of the cylindrical body, and scanning is performed by the photoelectric sensor 64 during this time. . Then, in synchronization with the position sensor output, an opacity gate signal is generated as shown in FIG. The defect detection circuit is operated, and the second defect detection circuit is operated during the period when the gate signal is off.

[Problem to be solved by the invention]

Conventionally, defects in a cylindrical object consisting of an opaque part and a transparent part have been detected in the manner described above, but in this conventional method, the synchronization between the position sensor output and the opaque gate signal may be out of sync. This made it impossible to perform proper scanning of cylindrical objects using photoelectric sensors, and the gate signal for opacity was fixed so that it always changed to high level in the first half of the position sensor output and to low level in the second half. Therefore, if the rotating object 3 to be inspected advances with the opaque part at the beginning, correct defect detection is possible, but conversely, if the rotating object 3 advances with the transparent part at the beginning, the defect cannot be detected. The drawback was that it was impossible to do so.

The present invention has been made in order to eliminate the drawbacks of the prior art as described above, and therefore, an object of the present invention is to solve the problem that even if a cylindrical object advances with the opaque part leading, or with the transparent part leading, It is an object of the present invention to provide a defect detection circuit for an object consisting of transparent and opaque parts, which enables defect detection by generating an appropriate gate signal in response to advances in technology.

[Key points of the invention]

The main points of the configuration of the present invention are that an object defect detection circuit consisting of transparent and opaque parts is provided with means for irradiating light onto the object being conveyed, and receiving reflected light from the object and converting it into an electrical signal. a first detection circuit that receives an electric signal from the photoelectric conversion means and detects a pulse-like portion rising from low to high among the signal components of the electric signal; a second detection circuit that receives an electrical signal from the photoelectric conversion means and detects a pulse-like portion falling from high to low among the signal components of the electrical signal; When the signal level exceeds the reference voltage, a first level signal is output, and when the signal level is lower than the reference voltage, a second level signal different from the first level is output, so that the transparent part of the object being conveyed is a cutout circuit that cuts out a transparent part period in which light is irradiated and an opaque part period in which the opaque part is irradiated; and when the cutout circuit cuts out the transparent part period, the second level signal is used. and a gate circuit that validates the output of the first detection circuit and validates the output of the second detection circuit using the first level signal when the opaque region period is being extracted. be.

〔Example〕

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 7 is a block diagram showing one embodiment of the present invention. In the figure, 3 is a cylindrical object consisting of an opaque part and a transparent part, 64 is a photoelectric sensor, 58 is an illumination lamp, 5 is an amplifier, 6 is a rising signal detection circuit for detecting defects in the transparent part, and 7 is an opaque part. A falling signal detection circuit for detecting defects in the
8 is a comparator, 9 is a counter, 31 is a digital comparator, 32 is a determination circuit, and 33 is a discharge section.

FIG. 8 is a signal waveform diagram of main parts in the circuit of FIG. 7.

The operation of the circuit shown in FIG. 7 will be explained with reference to FIG. After the output of the photoelectric sensor 64 is amplified by the amplifier 5, it is inputted not only to the rising signal detection circuit 6 and the falling signal detection circuit 7, but also to the + of the comparator 8.
It is also input to the side input terminal. On the other hand, the reference voltage Th ₁ is input to one input terminal of the comparator 8 .

As shown in FIG. 8, the output of the photoelectric sensor 64 (more specifically, the output after amplification by the amplifier 5) is applied to the cylindrical object 3 using the reference voltage Th ₁ as a threshold value.
When scanning an opaque area, the reference voltage
It is larger than Th ₁ and smaller than the reference voltage Th ₁ when scanning a transparent part. Therefore, the output wave composition of the comparator 8 is at a high level during the period when the photoelectric sensor 64 is scanning the opaque part of the cylindrical object 3, as shown in FIG. During the scanning period, the level is low. According to the output of the comparator 8, during the period when the opaque area is being scanned, the AND gate _A2 is open and passes the output of the falling signal detection circuit 7, but the AND gate _A1 is closed due to the presence of the inverter I. , the output of the rising signal detection circuit 6 is not passed through.
Similarly, during the period when the transparency is being scanned,
Since AND gate _A2 is closed and AND gate _A1 is opened, only the output of the rising signal detection circuit 6 is allowed to reach the OR circuit OR.

In this way, defects can be detected in the cylindrical object 3 consisting of an opaque part and a transparent part, regardless of whether the opaque part or the transparent part advances first.
The detected defect signal is counted by a counter 9,
The counting result is compared with a certain reference value S in the digital comparison circuit 31, and when it exceeds it,
The comparison circuit 31 generates an output, and the determination circuit 32
Since the cylindrical object 3 has a defect, it is determined to be defective, and the ejection section 33 is operated to eject the cylindrical object 3 as a defective product.

FIG. 9A is a block diagram showing an example of the falling signal detection circuit 7 in FIG. 7, and FIG. 9B is a waveform diagram of various signals in FIG. 9A.

In FIG. 9A, 35 is a differentiator, 36, 37
are each a comparator, and 38 is a timer (for example, a monostable multivibrator). Comparator 3
Comparator 6 generates an output when there is an input exceeding the reference voltage Th ₂ , and comparator 37 similarly generates an output when there is an input exceeding the reference voltage Th ₃ .

As is clear from the waveform diagram in Fig. 9B, the circuit operation is such that when a falling signal as a flaw signal is input, it is differentiated by the differentiator 35, and the differential output exceeds the threshold value _Th2. The portion exceeding the threshold Th 3 is output from the comparator 36, and the portion exceeding the threshold Th ₃ is output from the comparator 37. The output of comparator 36 starts timer 38. If the logical product of the output of the timer 38 and the output of the comparator 37 is created by the AND gate _{A3 and} output, this becomes the detection power of the falling signal.

FIG. 10A is a block diagram showing an example of the rising signal detection circuit 6 in FIG.
It is a waveform diagram of each part signal in figure 0A.

In FIG. 10A, 35A is a differentiator, 36
A and 37A are comparators, 38A is a timer, I is an inverter, and _A4 is an AND gate. The comparator 36A generates an output when there is an input exceeding the reference voltage _Th4 , and the comparator 37A similarly generates an output when there is an input exceeding the reference voltage _Th5 .

Since the circuit operation is considered to be analogically clear from the explanation of the circuit operation regarding FIG. 9A explained earlier by referring to the waveform diagram of FIG. 10B,
Further explanation will be omitted.

〔Effect of the invention〕

According to the present invention, the flaw detection power from the rising signal detection circuit and the falling signal detection circuit is transparent,
Automatic selection is made based on the cutting signal from the opaque part cutting circuit, and it is now possible to reliably catch the flaw signal regardless of whether the transparent part comes first or comes later. For example, a false flaw signal (a rising signal shown in FIG. 6h) due to halation occurring in the opaque body portion can also be removed.

In the description of the embodiment, the case of a cylindrical object in which a transparent body and an opaque body are joined together has been described.
In principle, the present invention can sufficiently cope with the case where cylindrical objects consisting only of transparent bodies or cylindrical objects consisting only of opaque bodies arrive at the same time. Furthermore, it is clear that the present invention can be similarly applied to cases where flaws (holes) are detected by scanning sheet-like objects with a photoelectric sensor in addition to cylindrical objects.

[Brief explanation of drawings]

Figure 1 is a front view showing the entire general capsule appearance inspection device, Figure 2 is a side view of the same, and Figure 3 is the first
A partially cutaway sectional view showing an enlarged view of the main part in the figure, Figure 4a is a diagram explaining the principle of defect detection in opaque bodies, Figure 4b is a diagram explaining the principle of defect detection in transparent bodies, Figure 5 6 is a perspective view showing how a cylindrical object is scanned by a photoelectric sensor, FIG. 6 is an output waveform diagram of the photoelectric sensor in FIG. 5, FIG. 7 is a block diagram showing an embodiment of the present invention, and FIG. 7. FIG. 9A is a block diagram showing an example of the falling signal detection circuit in FIG. 7. FIG. 9B is a waveform diagram of various signals in FIG. 9A. FIG. 10A 10 is a block diagram showing an example of the rising signal detection circuit in FIG.
FIG. B is a waveform diagram of each part signal in FIG. 10A. Symbol explanation, 1a...opaque body, 1b...transparent body, 2a, 2b...hole, 2a', 2b'...flaw signal,
3...Cylindrical object, 5...Amplifier, 6...Rising signal detection circuit, 7...Falling signal detection circuit, 8...
Comparator, 9... Counter, 31... Digital comparator, 32... Judgment circuit, 33... Discharge unit, 35
... Differentiator, 36, 37 ... Comparator, 38, 39
……timer.

Claims (1)

[Scope of Claims] 1. A defect detection circuit for an object consisting of transparent and opaque parts, comprising means for irradiating light onto the object being conveyed, and receiving reflected light from the object to generate an electrical signal. a first detection circuit that receives an electric signal from the photoelectric conversion means and detects a pulse-like portion rising from low to high among the signal components of the electric signal; a second detection circuit that receives an electric signal from the photoelectric conversion means and detects a pulse-like portion falling from high to low among the signal components of the electric signal; and a second detection circuit that receives the electric signal from the photoelectric conversion means; and outputs a first level signal when the signal level exceeds the reference voltage;
By outputting a signal at a second level different from the first level when the level is lower than the first level, light is irradiated to the transparent portion of the object being conveyed and the opaque portion thereof is irradiated with light. a cutout circuit that cuts out the opaque region period, and when the cutout circuit cuts out the transparent region period, the output of the first detection circuit is enabled by the signal at the second level, and the opaque region period is cut out. a gate circuit for validating the output of the second detection circuit by the signal at the first level when the object is detected. 2. In the defect detection circuit for an object comprising transparent and opaque parts according to claim 1, the first detection circuit includes a differentiator for differentiating the electrical signal from the photoelectric means, and a differentiator for differentiating the output of the differentiator. A first comparator and a second comparator that output a pulse signal when a portion of the signal component is below a low level threshold and a portion above a high level threshold is input, respectively. , an inverter connected to the output side of the first comparator, a timer that is triggered by the output of the second comparator and outputs a pulse signal of a predetermined period, and a combination of the output of the timer and the output of the inverter. and an AND circuit that takes a logical product, and the second detection circuit includes a differentiator that differentiates the electrical signal from the photoelectric means, and a low-level threshold value of each of the signal components of the output of the differentiator. a third comparator that outputs a pulse signal when a portion below the high level threshold and a portion above the high level threshold are input; and a fourth comparator, which is triggered by the output of the third comparator A defect detection circuit for an object made of transparent and opaque parts, comprising a timer that outputs a periodic pulse signal, and an AND circuit that takes an AND circuit between the output of the timer and the output of the fourth comparator. .