JPH037260B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a bottle inspection device that inspects the presence or absence of defects in the open end surface of a bottle, which serves as the sealing surface. If there is a defect on the open end surface (hereinafter referred to as the "top") of the bottle, the sealing performance when the sealing cap is placed will be impaired, so bottles with defects must be discarded. Conventionally, in order to detect this type of defect, inspection equipment optically scans the top of the bottle, converts the reflected light into an electrical signal, and detects defects in the top from the abnormality of the electrical signal. Various proposals have been made. However, with this type of inspection equipment, differences in the reflectance of the top of individual bottles,
Deterioration of floodlights over time, changes in environmental brightness over time,
Fluctuations in the power supply voltage of the emitter will cause large fluctuations in the electrical output of the light receiving element even if there is no defect, and as a result, the average level of the processed signal will also change greatly, making it difficult to detect defects with high precision and reliability. This was a contributing factor to the decline in sexual performance. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a bottle inspection device that can detect various defects that may occur on the top of a bottle with higher precision and reliability. In order to achieve this object, the present invention comprises: a) a light projector that emits light toward the open end surface of a bottle; and b) receives reflected light from the open end surface and outputs an electrical signal at a level corresponding to the amount of received light. c) a drive device that rotates the bottle so that the bottle opening end face is sequentially illuminated over the entire circumference; and d) an amplifier with a variable amplification degree that amplifies the output signal of the photoelectric conversion element. and e) a memory that stores the output signal of this amplifier for each bottle; and f) of the data stored in this memory, the average value of the data for the latest predetermined number of bottles in the past is calculated, and the average value is calculated. (g) an arithmetic control means for adjusting the amplification degree of the amplifier so that the amplification factor becomes a predetermined value; This bottle inspection device comprises a comparison calculation means for outputting a defect signal when the defect signal is detected. Hereinafter, the present invention will be explained in detail with reference to embodiments shown in the drawings. FIG. 1 shows a bottle 1 having a top 2 to be inspected;
A light projector 3 emits light from diagonally above the bottle 1 toward the ceiling 2, and a photoelectric conversion element 4 that receives reflected light from the ceiling 2 and outputs an electrical signal at a level corresponding to the amount of received light. The bottle 1 is rotated through at least one rotation by a drive (not shown) in the inspection position for optical scanning over the entire circumference of the top 2. The device parts up to this point can be configured using conventionally known parts as they are. As shown in FIG. 2, the output electrical signal of the photoelectric conversion element 4 is stored in a memory 7 via an amplifier 5 with a variable amplification degree and an AD converter 6. On the other hand, the rotational speed of the bottle 1 is detected by a speed detector 8 in conjunction with the movement of the drive device that rotationally drives the bottle 1, and the detected value and the setting of the bottle diameter setting section 9 which sets the bottle diameter each time are set. Based on this value, the scanning speed of the top 2 that is optically scanned is calculated by the top peripheral speed calculator 10. Based on the calculation results of the calculator 10, the A-D converter 6 ensures that the pitch of the data collected during one revolution of the bottle 1 is always constant regardless of the speed of the drive device or the bottle diameter. It is adjusted via the conversion timing setter 11 as follows. Since the data output from the A-D converter 6 is stored in the memory 7 as a series of digital quantities for each bottle, the arithmetic controller 12 first performs the following calculations based on the stored data. . For convenience, let us assume that the contents of the memory 7 are represented in analog form as shown in FIG. A predetermined number (for example, 10 pairs) of D ₁ , D ₂ ...D _o
Find the average value P ₁ using . In other words, the average value of the data D ₁ , D ₂ ... of each bottle is D ₁ , D ₂ , ...
As, P ₁ =1/n _o 〓 ^k=1 is determined. Although the average reflected light signal level is somewhat exaggerated in FIG. 3, as if the average reflected light signal level differs greatly between individual bottles, in reality, this difference is small within the same production lot. Therefore, by averaging the data for a predetermined number of past bottles (for example, 10 bottles), the influence of abnormal data due to defects in specific bottles is weakened. This average value P ₁ is constantly updated as the bottle inspection progresses, by discarding the oldest data used to calculate the average value and replenishing it with data for the latest bottles. It shall be. Therefore, in order to operate the electric circuit device stably and correctly, it is desirable to adjust the signal level to a predetermined value, as described above, and this level is set in the arithmetic controller 12, and the above-mentioned average value P ₁ matches the set value, the arithmetic controller 12 adjusts the amplification degree of the amplifier 5 via the DA converter 13. The output signal of the photoelectric conversion element 4, which has been amplified in this way to become an electric signal at a constant level, is A-
The data is converted into D and stored in the memory 7. Here, using the stored data regarding the bottle inspected last, that is, the bottle to be inspected, the comparator 14 determines whether or not there is a defect in the bottle to be inspected. Therefore,
Calculate the average value P ₀ for the bottles to be inspected, and extract the maximum value Px and minimum value Pz from a series of data for one bottle, and calculate △P ₀ = |P1−
It is determined whether P ₀ | and △Pm=Px−Pz are within or exceed each predetermined limit value. In the former case, it is determined that there is no defect, or even if there is a defect, it is within an allowable range, and in the latter case, it is determined that there is a defect and a defect signal is output. This defect signal can be used, for example, via the driver 15, as a signal for rejecting defective bottles in a production line, or as a signal for recording, warning, process control, etc. Next, a specific example of the waveform of the output signal of the photoelectric conversion element 4, that is, the output signal of the amplifier 5, and the defects corresponding thereto will be explained. Figure 4 shows a case where the average value P ₀ specific to the bottle under test almost matches the average value P1 for the series of bottles described above, but a pulse-like abnormal waveform with a very narrow width and small amplitude appears. , ΔPm are also below a predetermined limit value, and this is determined by the comparator 15 to be normal (no defect). This case corresponds to a case where small dust such as cotton dust is attached to the top 2 of the bottle 1. Figure 5 shows a gradual slope of change as a whole, and the difference △P ₀ between the average value P ₀ and the average value P1 is also the same as the difference △Pm between the maximum value and the minimum value. Both of these values are within predetermined limit values, and this case is also determined to be normal. Figure 6 shows a case where the difference △Pm exceeds the limit value due to the appearance of a relatively large positive pulse, and this is called the closed blister CB illustrated in Figure 11. Respond to defects that occur. In Fig. 7, unlike Fig. 6, the difference △Pm exceeds the limit value due to the appearance of a relatively large negative pulse, and this is the case where the top line in Fig. 11
TS, mouth burning KB in Figure 12, oven/
Corresponds to a defect called blister (open bubble) OB. Fig. 8 shows a type that makes one reciprocation with a gentle slope as a whole, and △Pm is larger than a predetermined limit value, which is correctly indicated by the broken line 2T as shown in Fig. 14. This corresponds to a defect called sky tilt, in which the sky 2 is tilted even though the sky should be horizontal. FIG. 9 shows a case where a relatively large valley appears in the waveform and ΔPm is also large. This corresponds to the defects called sky wave TN and sky flow TF as shown in FIG. FIG. 10 shows a case where the waveform is flat as a whole, but the level is low, and the average value P ₀ is much smaller than the average value P 1 and ΔP ₀ exceeds a predetermined limit value.
This occurs when the height Hs of bottle 1 does not reach the specified height dimension Ht and exceeds the allowable error range, as shown in Figure 15, or when the opening of bottle 1 is completely insufficiently formed. corresponds to In the case of the waveforms shown in FIGS. 6 to 10 described above, defects as shown in FIGS. 11 to 15 exist, respectively, and the comparator 14 outputs a defect signal. It is preferable that the limit value or threshold value for determining whether or not a defect is present is set at different levels depending on the characteristics of the defective signal, that is, the type of defect on the top of the bottle to be detected. Recognition of waveform characteristics and setting of limit values based on the recognition results can be performed using the comparator 14. Next, an example of recognizing the characteristics of a signal waveform diagram and setting a limit value will be described. First, the types of defects are roughly divided into the following three types. #1: Mouth burning KB (Fig. 7, Fig. 12) Open blister OB (Fig. 7, Fig. 12) Top suji TS (Fig. 7, Fig. 11) #2: Closed blister CB (Fig. 7, Fig. 11) Figure 6, 1st
(Fig. 1) #3: Tenpa TN (Fig. 9, Fig. 13) Tennami TF (Fig. 9, Fig. 13)) Based on this classification, defects are determined for the entire circumference of the bottle mouth. The length of the corresponding defective signal part is a) 0.01 to 0.1 in the dark direction for #1 defect.
When it is %. b) 0.01 to 0.1 in the bright direction for #2 defect
c) For defect #3, if it is 10 to 30% in the dark direction, it is preliminarily determined that there is a defect, and furthermore, depending on the use of the bottle and the sealing structure, as shown in the table below. When the allowable limit value, that is, the allowable limit value of the deviation from the average value P1, is exceeded, it is finally determined that there is a defect.

[Table] As exemplified here, the limit values are relatively small, but according to the present invention, it is possible to account for differences in the reflectance of the top of individual bottles, aging of the projector, fluctuations in power supply voltage, and even Even if the brightness of the inspection location changes over time, the amplification level of the amplifier installed in the signal processing system is adjusted each time so that a signal with a constant average level is always output. Therefore, it is possible to provide a highly accurate and highly reliable bottle inspection device that is free from malfunctions due to signal level fluctuations. In the embodiment, a digital circuit has been described because it simplifies the configuration of the memory and the arithmetic unit, but in some cases, the entire device may be configured only with analog circuits. Also,
In the apparatus shown in FIG. 2, the arithmetic controller 12 and the comparator 14 may be configured to share a common computer.

[Brief explanation of the drawing]

FIG. 1 is a side view showing the optical arrangement of a light projector and a photoelectric conversion element in the device of the present invention, FIG. 2 is a block diagram showing an embodiment of the present invention, and FIG. 3 is an amplification of the amplifier of the present invention. Waveform diagrams 4 to 10 are waveform diagrams for explaining the degree adjustment method, and waveform diagrams 11 to 10 are waveform diagrams showing specific examples of signal waveforms output from the amplifier.
FIG. 13 is a partial perspective view showing various examples of defects occurring on the top of the bottle, and FIGS. 14 and 15 are side views of the bottle showing still other examples of defects. 1...Bottle, 2...Top (opening end surface), 3...Light emitter, 4...Photoelectric conversion element, 5...Amplifier, 7...
...Memory, 12... Arithmetic controller, 14... Comparison calculator.

Claims (1)

[Scope of Claims] 1 a) A light projector that emits light toward the open end surface of the bottle; b) A photoelectric conversion element that receives reflected light from the open end surface and outputs an electrical signal at a level corresponding to the amount of received light. and c) a driving device that rotates the bottle so that the bottle opening end face is sequentially illuminated over the entire circumference; d) an amplifier with a variable amplification degree that amplifies the output signal of the photoelectric conversion element; and e) a memory for storing the output signal of this amplifier for each bottle; g) arithmetic control means for adjusting the amplification degree of the amplifier to a predetermined value; A bottle inspection device comprising a comparison calculation means for outputting an output.