JPS6115366B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for automatically inspecting whether a predetermined cap is attached to the opening of a bottle-shaped container.

In a bottling line where a large number of bottle-shaped containers are sequentially conveyed and filled with predetermined contents, and predetermined caps are automatically attached to the openings of the containers one after another, it is necessary to check whether or not the caps have been attached without visual inspection. When automatic detection is performed using equipment, most conventional devices use air nozzle back pressure type detectors that utilize the nozzle-flutter principle. With this air-type detector, in order to increase the difference between the output when inspecting a container with a cap and the output when inspecting a container without a cap, the various conditions of the detector must be set. It requires extremely difficult and precise adjustment, and there is the inconvenience of having to precisely readjust the detector settings (especially mechanical ones) every time the container to be inspected changes, and the settings are delicate. Its reliability is also low. Some attempts have been made to use a single photoelectric element to detect the presence or absence of a cap based on the amount of light reflected from the opening of the container, but in this case, it is difficult to increase the difference in output depending on the presence or absence of a cap. This was difficult and resulted in many false positives, making it impractical for practical use.

The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to make it possible to perform a highly reliable test by making the difference in detection output depending on the presence or absence of a cap very large under simple setting conditions. That is, in the present invention, the focus is adjusted to the opening height of the bottle-shaped container to be transported in the middle of the transport line, and the line-shaped field of view is positioned to intersect with the transport direction, and the image is divided into bright and dark. a line-type imaging means for converting into a value and outputting it; a container arrival detection means for non-contact detecting that the main body of the bottle-shaped container has arrived in front of the field of view of the imaging means; frequency synchronization with the conveyance speed of the conveyance line. pulse generating means for generating a pulse train; counting a certain number of the pulses from the time when the arrival of the container is detected, thereby determining that the vicinity of the opening of the container is passing within the field of view of the imaging means; an opening passage detection means for detecting that; during a period in which it is detected that the opening is being passed;
The present invention is characterized by comprising: determining means for determining the presence or absence of a cap in the bottle-shaped container based on the size of the total bright area (or dark area) of the image obtained from the imaging means;

First, the principle of this invention will be conceptually explained based on FIGS. 1 to 3. The illustrated embodiment relates to a container that is fitted with a cap that has a pore for liquid injection inside the sealing cap, as seen in containers for hair conditioners and lotions. In the latter stage, the presence or absence of the inner cap is inspected.

In FIG. 1, a container 1 sent out from a cap mounting section is normally fitted with a cap 3 having a small hole 4 at the upper end of its cylindrical opening 2, and placed on a conveyor 5. and is conveyed in the direction of arrow A. A light source 6 and a scanning detector 7 using an image sensor such as a CCD or PDA are arranged above the conveyor 5, and when the container 1 passes below these, the light from the light source 6 is emitted. is applied to the upper surface of the container 1, that is, the opening portion to which the cap 3 is attached, from obliquely above, and the scanning detector 7
In this step, an optical image of the opening of the container 1 formed by the lens is projected onto the light receiving surface of the image sensor. As is well known, the image sensor of the scanning detector 7 has a light-receiving surface in which a large number of picture elements (photoelectric conversion elements) are arranged in a straight line.
Signals corresponding to the amount of light received by each picture element are sequentially output in synchronization with a predetermined control signal. The scanning detector 7 is arranged so that the linear light-receiving surface is perpendicular to the moving direction of the optical image of the opening of the container 1 as the container 1 is transported. Scanning is performed in a direction perpendicular to the transport direction.

Reference numeral 8 designates a photoelectric non-contact switch in which a light emitter 8a and a light receiver 8b are arranged facing each other on both sides of a predetermined position of the conveyor 5. 1 is conveyed to the conveyor 5 and reaches a predetermined position before the inspection position by the scanning detector 7. That is, the light beam projected from the light emitter 8a to the light receiver 8b is
When the contactless switch 8 is blocked by the thick lower part of the switch 8, the output of the non-contact switch 8 becomes a high level "1". Also,
Reference numeral 9 indicates a rotation detector connected to the rotation mechanism of the conveyor 5, and this rotation detector 9 generates a pulse signal synchronized with the operation of the conveyor 5 (with a frequency proportional to the operation speed).

Now, FIG. 2A shows a state in which the scanning detector 7 scans the container 1 without the cap 3 attached. In this case, since the ring-shaped upper end surface of the cylindrical opening 2 of the container 1 has high brightness, the optical image M of this portion becomes a bright ring-shaped image as shown in the figure.
Since scanning by the scanning detector 7 is repeated at a constant period and the container 1 is transported at a constant speed, the scanning lines of the scanning detector 7 with respect to the image M are as shown in A of FIG. The statue M
are scanned in parallel many times at regular intervals.
Therefore, the output signal of the detector 7 for each scan is:
As shown in Figure B, the pulse signal corresponds to the amount of light received by each pixel of the image sensor, and the output in the part where the bright ring-shaped image M is projected is high level, and the output in the other dark parts is high. The output of the corresponding picture element becomes a low level (note that a shaped output signal is obtained from the detector 7 as shown in the figure). As is clear here, the number of pulse signals in the output signals for each scan,...
, corresponds to the length of the overlapping portion of the image M).

Similarly, in FIG. 3A, the cap 3 is connected to the cylindrical opening 2.
2 shows the state of scanning by the scanning detector 7 with respect to the container 1 that is correctly attached. In this case, the disc-shaped upper surface of the cap 3 shines brightly, and the optical image M' of this portion becomes a bright circular image (note that a small dark area is formed by the pore 4 at the center of this circular image). The scanning lines for this circular image M' are the same as in the above case, and the image M' is scanned in parallel many times at regular intervals, as shown in . Therefore, the output signal of the scanning detector 7 for each scan is a high-level pulse signal in the portion corresponding to the circular image M', as shown in FIG. That is, the output signal for each scan,
The number of pulse signals generated during ,...corresponds to the size of the bright part when the image M' is converted into bright and dark binarized (the length of the overlapping part between the image M' and each scanning line, ,...) .

Comparing the case of Fig. 2 with the case of Fig. 3, the area of the ring-shaped upper end surface of the cylindrical opening 2 of the container 1 without the cap 3 attached is naturally larger than the area of the disc-shaped upper surface of the cap 3. Since the image is sufficiently small, the size of the bright part of the ring-shaped image M and the circular image M' is larger in the image M', and the difference between them is extremely large. Therefore, by counting how many pulse signals are generated in the output signal of the scanning detector 7 for each scan, the size of the bright area for each scan can be quantized and detected. However, based on the value, it can be determined whether the cap 3 is attached to the container 1 or not.

However, at the beginning and near the end of the scan of the opening of the container 1 by the scanning detector 7, the ring-shaped image M in the case of FIG. 2 without the cap 3, and the ring-shaped image M in the case of FIG. 3 with the cap 3. With respect to the circular image M', the scanning line by the detector 7 is close to the tangent to each image. In such a state, the overlapping length of the image M and the scanning line and the image
The difference in the overlapping length between M' and the scanning line is small, and if the presence or absence of the cap 3 is discriminated based on the output of the detector 7 at this time, the discrimination accuracy will be degraded.

Therefore, in the present invention, the non-contact switch 8 and the rotation detector 9 are used to substantially limit the inspection area by the scanning detector 7, and the scanning detector 7 scans the center of the opening of the container 1. The presence or absence of the cap 3 is determined based on the output of the detector 7 only in this state (the state in which the range indicated by the symbol E in FIGS. 2 and 3 is scanned). Next, one embodiment of the present invention will be described in detail based on FIGS. 4 and 5.

In FIG. 4, the output a of the non-contact switch 8
becomes "1" when the container 1 to be inspected reaches a predetermined position in front of the inspection position, and this "1" output enables the counter C1 to count and opens the AND gate G1. The output pulse b of the rotation detector 9 is supplied to the count input cp of the counter C1. Since the output pulse b of this rotation detector 9 is synchronized with the operation of the conveyor 5, the amount of movement of the conveyor 5 can be determined by counting it. That is, the count number on the counter C1 corresponds to the conveyance amount of the container 1 to be inspected after the non-contact switch 8 is turned on.

Therefore, after the container 1 turns on the contactless switch 8, the scanning detector 7 scans the opening line Es of the inspection area E shown in FIGS. 2 and 3 with respect to the opening of the container 1. The amount of movement s of the container 1 until it reaches the state where it is detected, and the end line Ee of the inspection area E with respect to the opening of the container 1 after the container 1 turns on the non-contact switch 8 are scanned. The amount of movement e of the container 1 until it is in a state of being scanned by the container 7 is determined in advance, and the amount of movement s is determined in advance.
and the number of output pulses of the rotation detector 9 corresponding to e
Ns and Ne are matched circuits 10 and 1, respectively.
Set to 1. Then, the count output of the counter C1 is introduced into the coincidence circuits 10 and 11, and when the count output matches the set number Ns, the flip-flop FF1 is set by the output d from the coincidence circuit 10, and the flip-flop FF1 is set by the output d from the coincidence circuit 10. When the count output matches the set number Ne above,
The flip-flop FF1 is reset by the output e from the matching circuit 11.
Therefore, the output f of the flip-flop FF1 becomes "1" during the period when the container 1 to be inspected is at a position where the inspection area E of the opening thereof is scanned by the scanning detector 7. .

As mentioned above, the inspection area E can be defined by the output f of the flip-flop FF1, but
Furthermore, in this embodiment, while the scanning detector 7 is scanning the inspection area E, the scanning output is transmitted to the rotation detector 9.
I am trying to sample it in synchronization with the output. In other words, since the scanning frequency of the scanning detector 7 is relatively high, a very large number of scans are included during the inspection of the inspection area E. is sufficiently lower than the above scanning frequency at the normal operating speed of the conveyor 5), by utilizing only M scans by the scanning detector 7, during the inspection of the inspection area E, the scanning frequency by the scanning detector 7 is substantially (Ne
-Ns) It is limited to M times.

For this purpose, a frame signal g that generates one pulse immediately before each scan is extracted from the scanning detector 7, and an AND gate G2 is used to combine this frame signal g, the output f of the flip-flop FF1, and the rotation detector 7. Take the AND of the output b of 9.
Then, the output h of this AND gate G2, that is, the frame signal included in one pulse of the rotation detector 9 during the inspection of the inspection area E, is input to the counter C2.
The number of pulses of the frame signal f included in one pulse of the rotation detector 9 is supplied to the count input CP of the rotation detector 9, and this counter C2 is reset at each falling edge of the output pulse of the rotation detector 9. count. Furthermore, the count output of this counter C2 is introduced into the coincidence circuit 12 where (M+1) is set, and this count output is (M+
1), the output signal i from the matching circuit 12
to be sent. And gate G
The first pulse of output h of 2 sets flip-flop FF2, and the output i from match circuit 12 resets flip-flop FF2.

As a result, during the inspection period of the inspection area E, the output j of the flip-flop FF2 becomes "1" for each pulse of the output b of the rotation detector 9 for M scanning times of the scanning detector 7.

Therefore, the AND gate G3 calculates the AND of the detection output k of the scanning detector 7 and the output j of the flip-flop FF2, and outputs the output of the flip-flop FF2.
Only during the period when the output j of the scanning detector 7 is "1", the detection output k of the scanning detector 7 is supplied to the count input CP of the counter C3.
3 is reset by the frame signal g.
Therefore, when the output j of the flip-flop FF2 is "1", the number of pulses included in the detection output for each scan of the scanning detector 7 (corresponding to the size of the bright area as described above) ) is counter C3
It is counted by.

The number N of pulses for each scan outputted from the counter C3 is supplied to the comparator circuit 13, and
The comparator circuit 13 supplies one pulse to the count input CP of the counter C4 when N≧No (this is assumed to be capped). ,vice versa,
If N<No (this is assumed to be no capping), one pulse is supplied to the count input CP of the counter C5.

That is, among the detection outputs of (Ne-Ns) M scans by the scanning detector 7 during the inspection period of the inspection area E, the number of scans determined to be capped is counted in the counter C4, and the number of scans determined to be capped is counted by the counter C4. The number of scans determined as such is counted by a counter C5. Then, at the end of the inspection of the inspection area E, the count number of the counter C4 and the count number of the counter C5 are compared in the size discrimination circuit 14, and if the count number of the counter C4 is large, the final value is determined from the size discrimination circuit 14. When a capped signal is output and, conversely, the count number of the counter C5 is large, a final capped signal is outputted from the magnitude discrimination circuit 14.

As explained in detail above, according to the present invention,
It is possible to select a part where a very large difference in test output is obtained depending on the presence or absence of a cap, define that part as the test area, and then discriminate the presence or absence of a cap with extremely high accuracy based on the test signal of that part. It can be done. Also, to set the above inspection area,
It can be performed electrically using a digital switch or the like, and has a variety of effects, such as being highly flexible for containers to be inspected.

[Brief explanation of the drawing]

The drawings illustrate the principle of the invention, and are
The figure is an explanatory diagram showing the relationship between the container conveyance line and the scanning detector.
4 is a block diagram of the apparatus to which the present invention is applied, and FIG. 5 is a timing chart showing the operation of each part in the same block diagram. 1... Container, 3... Cap, 5... Conveyor, 7... Scanning type detector, 8... Contactless switch, 9... Rotation detector, E... Inspection area.

Claims (1)

[Claims] 1. A device located in the middle of the conveyance line, whose focus is adjusted to the height of the opening of the bottle-shaped container being conveyed, and whose linear field of view is positioned to intersect the conveyance direction, and which displays an image. a line-type imaging means for outputting a bright and dark binary image; a container arrival detection means for non-contact detecting that the main body of the bottle-shaped container has arrived in front of the field of view of the imaging means; a conveyance speed of the conveyance line; pulse generating means for generating a frequency-synchronized pulse train; counting a certain number of the pulses from the time when the arrival of the container is detected, thereby detecting that the vicinity of the opening of the container is passing within the field of view of the imaging means; an opening passage detection means for detecting that; during a period in which it is detected that the opening is being passed;
A determination means for determining the presence or absence of a cap in the bottle-shaped container based on the size of the total bright area (or dark area) of the image obtained from the imaging means; Cap inspection equipment.