JPS6246803B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tablet inspection device, and particularly to a tablet inspection device for defective tablets whose thickness is thinner than that of non-defective tablets, commonly known as half-pellets. Since this type of semi-pellet is a serious defect, highly accurate detection is desired. By the way, conventionally, as this type of inspection apparatus, there are those that perform mechanical inspection and those that inspect using photoelectric sensors. However, although mechanical sorting machines are highly accurate, they are expensive, and methods using photoelectric sensors have limitations in detecting half-sized tablets due to variations in the thickness of good tablets.

Therefore, it is an object of the present invention to eliminate the above-mentioned drawbacks and provide a tablet inspection device with higher accuracy and lower cost.

In this invention, when the front or back side of a tablet containing a non-defective product and a half-sized tablet is imaged with a television camera (hereinafter also referred to as a TV camera), the image signal obtained during one horizontal scanning period has a sharp waveform for a non-defective product. On the other hand, we focused on the fact that the half-peller waveform has a flat waveform, and we can distinguish between the two based on this difference.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory diagram showing the external shapes of good and defective tablets, that is, semi-pellets, FIG. 2 is a block diagram showing one embodiment of the present invention, and FIG. 3 is a diagram showing another embodiment of the present invention. This is a block diagram showing an example, and FIG. 4 is a waveform diagram showing the waveforms of each part of FIG. be.

As is clear from Figure 1, the diameters of the good tablets ( ) and semi-pellets ( ) are almost the same, but their thicknesses are different.
When looking at this from the side, the good product GO1 has a roundness or bulge as a whole, whereas the non-performing
1 is not as round as a good product and is flat as a whole. When these tablets are observed directly from above with the naked eye, there is no difference between the good GO2 and the semi-pella NG2. However, as a result of repeated various experiments and studies by the present inventor, when these images are captured with a television camera, the signal obtained by one horizontal scanning line of the imaged signal is as shown in FIG. 4A. It has been found that, in general, a good product is observed as a sharp waveform a, whereas a semi-peller is observed as a waveform a' with a flat peak. The TV camera used here is one that is normally used to inspect tablets for dirt and chips.

Therefore, in the present invention, delay differentiation is performed twice in order to detect the flat portion of the signal obtained from the above-mentioned half-peller (see ○A in FIG. 4). As shown in FIG. 2, the signal from the TV camera 1 obtained by photographing the tablet 12 from directly above is amplified (inverted amplification) by the amplifier circuit 2, and one terminal of the differential amplifier circuit 4 and the delay circuit Add to 3. The delay circuit 3 applies a signal delayed by a certain time to the other terminal of the differential amplifier circuit 4. Then, the differential amplifier circuit 4 performs the first delay differentiation by taking the difference between the delayed signal and the signal before being delayed (see waveforms d and d' in FIG. 4C). As a result, the signal waveform of a non-defective product has a certain slope, and the signal waveform of a semi-peller has a flat part with no slope (see the part circled in FIG. 4C). The signal that has been delayed and differentiated once is sent to the differential amplifier circuit 6.
and delay circuit 5. The delay circuit 5 applies a signal delayed by a certain time to the other terminal of the differential amplifier circuit 6. Then, a second delay differentiation is performed by taking the difference in the differential amplifier circuit 6 (see waveforms f and f' in FIG. 4D). Due to the two-degree delay differentiation, there is a portion where a level difference occurs between the signal waveforms of the non-defective product and the semi-permanent product (see the portion marked with ◯ in Fig. 4D). Therefore, a reference level (see g in FIG. 4D) between this level difference is set to distinguish between non-defective products and semi-performing products. The signal that has undergone delayed differentiation twice is
It is applied to one terminal of the comparator circuit 8. A certain reference level is applied from the reference level setting circuit 7 to the other terminal of the comparison circuit 8 for comparison. The signal binarized by the comparator circuit 8 becomes one pulse when the product is good (see h in Fig. 4E), and becomes 2 pulses when it is half-perfect (see h' in Fig. 4E). This signal is transferred to the flip-flop 9
is added to one terminal of the AND circuit 10. The flip-flop 9 operates at the end of the first pulse and is for masking the first pulse (see i, i' in FIG. 4F). This signal is added to the other terminal of the AND circuit 10 and an AND is obtained. As a result, no pulse is output to the output terminal 11 in the case of a non-defective product (see j in G in Figure 4), and 1 pulse is output in the case of a half-peller.
A pulse is output (see j' in FIG. 4G). In this way, it is determined that it is a half-peller.

In the example shown in Fig. 2, one horizontal scanning period of the image signal from the TV camera was described, but if we consider one screen, even a good tablet will have a half-sized signal (flat at the peak) over several horizontal scanning lines. ), and therefore a pulse may be output to the output terminal 11. Therefore, as shown in FIG. 3, a counter circuit 14, a reference value setting circuit 15, and a comparison circuit 16 are newly added to the circuit configuration of FIG. 2 to count the number of pulses. In addition,
13 is the circuit shown in FIG. In one screen, pulses may be output to the output terminal 11 in FIG. 2 even in the case of a non-defective product, but the number should be smaller than the number of pulses in the case of a half-peller. Therefore, the number of pulses output on one screen is counted, and good products are distinguished from semi-performing products based on the counted number. That is, the counter circuit 14 counts the pulses output from the output terminal 11 in FIG. Then, the comparison circuit 16 compares this count number with a certain number set by the reference value setting circuit 15, and when the count number is greater than the set number, it is determined that it is a half-peller, and a signal is output to the output terminal 17. . By doing this, even if it is not possible to distinguish between non-defective products and half-pellets in the embodiment shown in FIG. 2, the newly added circuit configuration as shown in the embodiment shown in FIG. can be detected.

As described above, according to the present invention, a TV camera that normally inspects for dust and chips can be used without installing a new mechanical inspection device or photoelectric sensor inspection device for the purpose of inspecting tablets. The signal obtained by the TV camera is differentiated twice, and the defect signal unique to semi-pellets contained in the signal is extracted and inspected, so high-precision detection is possible with a simple configuration. This is the result.

In addition to the tablets described above, this invention can also be applied to similar shaped caramel and tyokolate foods.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the external shapes of good and defective tablets, that is, semi-pellets, FIG. 2 is a block diagram showing one embodiment of the present invention, and FIG. 3 is a block diagram showing another embodiment of the present invention. FIG. 2 is a block diagram illustrating an example;
FIG. 4 is a waveform diagram showing waveforms of various parts in FIG. 2. Description of symbols, 1...TV camera, 2...Amplification circuit, 3, 5...Delay circuit, 4, 6...Differential amplifier circuit, 8, 16...Comparison circuit, 7, 15...Setting circuit, 9 ...flip-flop, 10...and gate, 11...output terminal, 12...tablet, 14...
…counter.

Claims (1)

[Claims] 1. A television camera that images the front or back side of a tablet, and a first differential amplifier circuit that forms a difference between an image signal from the camera and a delayed signal obtained by delaying the image signal. , a second differential amplifier circuit that forms a difference between the output signal of this differential amplifier circuit and a delayed output signal obtained by delaying the output signal; and a comparison circuit that binarizes the image signal by comparing it with a reference level, and determines whether the tablet is good or not based on the number of signals binarized by the comparison circuit for each signal during one horizontal scanning period of the imaged signal. A tablet inspection device characterized in that it distinguishes and detects defective products. 2. A television camera that images the front or back side of a tablet, a first differential amplifier circuit that forms a difference between an image signal from the camera and a delayed signal obtained by delaying this image signal, and this differential amplifier circuit. a second differential amplifier circuit that forms a difference between the output signal of the output signal and a delayed output signal obtained by delaying the output signal, and compares the output signal of the second differential amplifier circuit with a preset reference level. and a counter that counts the signal binarized by the comparison circuit over a plurality of horizontal scanning lines, and compares the count value with a predetermined reference setting value. A tablet inspection device characterized in that it is configured to distinguish between good and defective tablets and detect them.