JPS6310780B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for inspecting bottles, and more particularly to a method for inspecting screw-top bottles, in which the inspection is performed by applying a light beam from a light source to the bottle mouth and receiving the light with a one-dimensional scanning camera.

Conventionally, many methods for inspecting bottles using photoelectric devices such as light projectors and light receivers have been proposed and implemented. However, when inspecting bottles or screw caps, the light beam changes in a complex manner due to the threads of the screw cap.
It has not been possible to perform sufficiently accurate inspections using conventional photoelectric devices, and in order to perform accurate inspections, it has been necessary to rely on the visual inspection of an inspector. Although this method of visual inspection by an inspector can perform an inspection with some degree of accuracy, it has drawbacks such as fatigue of the inspector and limitations on inspection speed.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the drawbacks of conventional inspection methods and to provide an inspection method that is accurate, fast, and capable of automatically inspecting screw cap bottles.

In order to achieve the above object, the inspection method of the present invention involves rotating the bottle to be inspected, applying light from a light source so as to pass through the screw part of the screw-top bottle, and receiving the transmitted light using a one-dimensional scanning camera. In this method, a light shielding plate is provided in the travel path of the light beam to prevent the entry of light beams that pass through threaded parts other than the threaded part to be inspected, and a horizontal light beam that has passed through the threaded parts is directed to the threaded part of the screw cap. A one-dimensional scanning camera located next to the bottle converts the signal into an electrical signal, and the quality of the screw thread on the screw cap bottle is determined based on changes in the pattern of the obtained electrical signal.

The present invention will be explained in detail below with reference to embodiments shown in the drawings.

FIG. 1 is a schematic diagram showing an embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a screw-cap bottle whose mouth is inspected for cracks, defects, and cracks. A large number of screw cap bottles 1 are transported on a conveyor (not shown) for inspection. 2 is a light source, and a light beam 3 is projected from the light source 2 onto the screw cap side wall 4 of the screw cap bottle 1. Reference numeral 5 designates an image sensor camera as a one-dimensional scanning camera that receives the light beam 3 projected from the light source 2. An image sensor camera (hereinafter simply referred to as a camera) is a one-dimensional scanning system in which, for example, a large number of CCD elements (charge-coupled devices) are arranged, and when light hits these CCD elements, the optical signal is converted into an electrical signal and an image signal is obtained. is a possible camera, and is itself a well-known camera. The camera 5 is disposed right beside the screw-cap side wall 6 of the screw-cap bottle 1. Reference numeral 7 denotes a light shielding plate, which is provided to prevent light from entering through the screw cap top 8 of the screw cap bottle 1. Note that the light source 2 is disposed below the light shielding plate 7 at a position substantially in the lateral direction of the screw opening side wall 4 so that the light beam 3 is projected onto the screw opening side wall 4 with the light shielding plate 7 as the upper limit.

The light beam 3 projected from the light source 2 is projected onto the screw cap side wall 4, is refracted there, and reaches the other screw cap side wall 6 through the bottle mouth lumen. Here, the light ray 3 is refracted again, but due to the screw thread of the screw port side wall 6, the number of light rays traveling horizontally from the screw port side wall 6 toward the camera 5 becomes four. 4 that passes through the screw port side wall 6
If you draw the image of the light beam from the book as seen from the camera 5 side, it will look like 4 of 21, 22, 23, 24 as shown in Figure 2.
light emitting parts are obtained. The scanning line of camera 5 is the second
Since they are arranged as shown in A in the figure, the camera 5 can obtain imaging signals of four pulses in one scan. Figure 2 shows the light emitting part of the bottle in a certain relative positional relationship between the screw cap bottle 1, the light source 2, and the camera 5. The parts are shown in Figure 3. As is clear from FIG. 3, in the case of a non-defective bottle, the number of light-emitting parts due to transmitted light is four or three. The reason why there are three cases is due to the difference in the thread conditions due to the rotation of the bottle.

On the other hand, assuming the case of a defective bottle, for example, if the bottle has a crack at the 270° position in Figure 3, the light emitting part of the bottle mouth will be replaced by the light emitting part at the top as shown in Figure 4 A. part disappears and becomes two light emitting parts. Also, refer to Figure 3.
If the screw thread on the bottle opening is missing at the 225° position,
Transmission is not smoothed in this part, and the middle two light emitting parts disappear, leaving only two light emitting parts, as shown in FIG. 4B.

As mentioned above, when the bottle is rotated once in Figure 1 and the pattern of the light-emitting part is checked at each rotation angle, the pattern of the light-emitting part at that part is different for bottles with defects in the bottle mouth or threads compared to good bottles. do. For one revolution of the screw cap bottle 1, the camera 5 performs sampling operation a sufficient number of times to extract the pattern and performs scanning, and an electronic circuit connected to the subsequent stage checks for different patterns and distinguishes between good bottles and defective bottles. Make a judgment.

FIG. 5 shows an example of a specific electronic circuit block diagram for detecting pattern differences between good bottles and defective bottles.

In FIG. 5, numeral 31 is a waveform shaping circuit that obtains a signal from the camera 5 and derives a rectangular wave pulse.
When the camera 5 performs a scanning operation on the screw cap bottle shown in FIG. 2, four pulses are delivered to the output terminal of the waveform shaping circuit 31 in one scan. 32 is a mode counter. Here, the mode refers to the rectangular wave of the imaging signal obtained for each scan, and mode 1 refers to the case where there is one rectangular wave, and mode 2 refers to the case where there are two rectangular waves. Modes 3 and 4 may be considered in the same way. Mode counter 32 is reset every scan. 33 is a setting device for setting the numerical signal 4; 34 is a comparator that receives and compares the output of the mode counter 32 and the numerical signal from the setting device 33; 35 is a setting device for setting the numerical signal 3; 36 is the output of the mode counter 32 and the setting device 35
This is a comparator that receives two numerical signals at its input and compares them. 37 is the output terminal 4<a of the comparator 34
When the output of the comparator 36 is "1", the terminal 38 derives this signal, that is, the mode over signal. When the output of the output terminal 3>a of the comparator 36 is "1", the terminal 38 derives this signal, that is, the mode rack signal. be.

Further 39,40,41,42 and 44,4
5, 46, 47 are latch circuits, and when the output of the output terminal 3=a of the comparator 36 is "1", the latch circuits 39, 41, 45, 47 receive this signal and output the input signal. The latch circuit 40, 4
When the output of the output terminal 3<a of the comparator 36 is "1", the input signals 2, 44, and 46 receive this signal and lead out the input signal to the output side. These latch circuits constitute a mode pattern overdetection circuit. 43 and 48 are terminals for deriving the mode pattern over signal.

51 is a mode 4 counter which receives the output of the output terminal 4=a of the comparator 34 as an input and counts the number of scans in mode 4 during one rotation of the bottle. 52 is a mode 3 counter which receives the output of the output terminal 3=a of the comparator 36 as an input and counts the number of scans in mode 3 during one rotation of the bottle. 53 is an arithmetic circuit which receives the outputs of both the mode 4 counter 51 and the mode 3 counter 52 and calculates the difference between their counts; 54 is a setter for setting a numerical value within a certain range; and 55 is the output of the arithmetic circuit 53. This is a comparator that receives the numerical signals from the setter 54 and compares the two. Further, 56 is a terminal for deriving a bottle failure signal when a signal "1" is obtained at the output terminal of the arithmetic circuit 53, that is, when the difference signal is out of the numerical range of the setter 54.

Next, the operation of the electronic circuit block diagram shown in FIG. 5 will be explained.

First, detection of defective bottles by mode over or mode rack will be explained. As shown in FIG. 3, when the inspection bottle is a good bottle, the number of light emitting parts is 4 or 3, and therefore the number of rectangular pulses output to the waveform shaping circuit 31 is 4 or 3 per scan. . Therefore, the output a of the mode counter 32 never becomes larger than 4 or smaller than 3 during one rotation of the bottle. Therefore, the signal "1" is not derived from either the output terminal 4<a of the comparator 34 or the output terminal 3>a of the comparator 36, and the signal "1" is not derived from the mode over signal derivation terminal 37 and the mode rack signal derivation terminal 38. No signal is derived. However, if the inspection bottle is a defective bottle as shown in FIG.
The output a of 2 becomes 2. A signal "1" is therefore obtained at the output 3<a of the comparator 36. This signal is derived from the mode rack signal terminal 38, and a determination is made as to whether the bottle is defective. Similarly, if five light emitting parts are generated due to a notch in the screw thread or the like, the output a of the mode counter 32 becomes five. Therefore, a signal “1” is obtained at the output terminal 4<a of the comparator 34, and this signal is led out to the mode over signal terminal 38. This signal also determines whether the bottle is defective.

Next, detection of defective bottles by mode pattern overflow will be described. In the case of a good bottle, as the bottle rotates, mode 4 will first follow, then mode 3, and then mode 4 will complete one rotation, or vice versa, the change will be from mode 3 group to mode 4 group to mode 3 group. Either one rotation ends at . However, if it is a defective bottle with defects such as screw threads, during one rotation of the bottle, the mode 4 group → mode 3 group → mode 4 group → mode 3 group → mode 4 group, or mode 3 group → mode 4 group → The mode group may be repeated many times, such as mode 3 group → mode 4 group → mode 3 group. Therefore, if the repeated mode pattern exceeds 3, the bottle is determined to be defective.

Now, if a good bottle rotates once, mode 3 groups → mode 4
Assuming that the sequence is repeated from group to mode 3 group, in the first mode 3 group, "1" continues to be derived from the output terminal 3=a of the comparator 36, and with this signal as a condition, the latch circuit 39 outputs its input. A high level signal "H" (logic "1") that is always applied to the output terminal is outputted. This output signal "1" is output from the latch circuit 40.
However, while mode 3 continues, the output of the comparator 36 at the output 3<a is not "1", so the output signal "1" is not derived at the output of the latch circuit 40. When shifting from mode 3 to mode 4, the output of the output terminal 3<a of the comparator 36 becomes "1", and under this signal, the latch circuit 40 derives the signal "1" applied to the input to the output side. . Next, when switching to mode 3 again, comparator 3
The output of output terminal 3=a of 6 becomes "1". On the condition that the output of the comparator 36 is "1", the latch circuit 41 derives the signal "1" applied to the input to the output side. However, in the case of a non-defective bottle, this completes one rotation, so the output "1" of the latch circuit 41 is added to the input of the latch circuit 42, but it is not led to the output side of the latch circuit 42, and the mode pattern over signal is output. No bottle failure signal is derived from the terminal 43. However, if the bottle is defective, mode 3 group → mode 4
Group→Mode 3 group, then Mode 4 group→Mode 3 group, and so on, so the transition to Mode 4 causes the output of the output terminal 3<a of the comparator 36 to become “1” again, and with this signal as the condition. The signal "1" applied to the input of the latch circuit 42 is obtained at the output side. This signal "1" is derived from the terminal 43 as a mode pattern over signal, and a defective bottle is determined. Also, the bottle is mode 4 group → mode 3 group → mode 4
Detection of a mode pattern overrun when the mode pattern changes with the group can be performed by the latch circuits 44, 45, 46, and 47 in the same manner as the latch circuits 39, 40, 41, and 42 described above.

The electronic circuit block diagram of FIG. 5 can detect defective bottles in other ways. The number of scanning lines in mode 4 is counted by mode 4 counter 51 during one rotation of the bottle, and the number of scanning lines in mode 3 is counted by mode 3 counter 5.
Count by 2. Then, the arithmetic circuit 53 calculates the difference between the contents of the mode 4 counter 51 and the mode counter 52, and adds the difference value to one end of the input of the comparator 55. The comparator 55 compares the numerical signal having a constant width from the setter 54 with the numerical value from the arithmetic circuit 53. In the case of a good bottle, the number of scanning lines in mode 4 and mode 3
The number of scanning lines is constant at 1, and the difference value is determined by the setting device 54.
Since the value is within the numerical range set by , no signal is derived from the terminal 56. On the other hand, in the case of a defective bottle with a defective screw thread, etc., the number of scanning lines in mode 4 or the number of scanning lines in mode 3 increases or decreases, and the difference value output from the arithmetic circuit 53 is set by the setting device 54. Either the value is too small to fall within the specified numerical range, or it becomes larger than the numerical value range. A signal "1" is therefore obtained at the output of comparator 55. This signal "1" is output to the terminal 56, and a defective bottle is determined.

The method of inspecting defective bottles by determining the difference in the number of scanning lines between mode 4 and mode 3 is that if there is a defect at the start of the screw thread, it cannot be detected by the mode over (mode rack) detection method or the mode pattern over detection method. This method is particularly effective.

In the electronic circuit block diagram shown in Figure 5, defective bottles can be inspected using any one of the mode over detection method, mode pattern over detection method, and scanning line number difference calculation method between mode 4 and mode 3, but it is recommended to use all three methods together. defective bottles can be detected more effectively.

FIG. 6 shows a schematic diagram showing another embodiment of the method of the present invention. The light source 2 is arranged above the light shielding plate 7,
This embodiment differs from the embodiment shown in FIG. 1 in that the light ray 3 is not transmitted through one screw-cap side wall 4 of the screw-cap bottle 1, but is transmitted only through the other screw-cap side wall 6. The mode in this example is mode 1 for good bottles.
and mode 2 only.

As described above, the inspection method of the present invention rotates the bottle to be inspected, installs a light-shielding plate so that light hits only the screw part to be inspected, and uses a one-dimensional scanning camera to convert the horizontal light beam that passes through the screw part into an electrical signal. Since the change in the electrical signal pattern is used to determine the quality of the screw threads on a screw cap bottle, even screw cap bottles with complex bottle necks due to screw threads can be accurately and quickly processed. It is possible to judge whether a bottle is good or bad without any human intervention.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an outline of an inspection method according to an embodiment of the present invention, FIG. 2 is a diagram showing the positional relationship between the scanning line of a one-dimensional scanning camera and the light emitting part of a screw cap bottle, and FIG. Figure 1 is a diagram showing the light emitting state of the bottle opening as seen from the camera side when a non-defective bottle is inspected in the example.
The figure shows an example of the luminous state of the mouth of a defective bottle, FIG. 5 is a block diagram of an electronic circuit applied to the embodiment of FIG. 1, and FIG. 6 shows an inspection method of another embodiment of the present invention. It is a figure showing an outline. 1 is a screw cap bottle, 2 is a light source, 3 is a light beam, 5 is a one-dimensional scanning camera, and 7 is a light shielding plate.

Claims (1)

[Claims] 1. A screw cap bottle inspection method in which a light beam from a light source is transmitted through the threaded part of the screw cap bottle while rotating the bottle to be inspected, and the transmitted light beam is received by a one-dimensional scanning camera. In addition, a light shielding line is provided in the travel path of the light beam to prevent the entry of light beams that pass through threaded parts other than the threaded part to be inspected, and the horizontal light beam that has passed through the threaded part is scanned in one-dimensional scanning at a position next to the screw opening. means for counting the number of rectangular waves per scan of the electrical signal obtained by converting it into an electrical signal with a camera, and means for determining the number by comparing it with a set number; A means for determining based on the difference between the number of scans in which a number appears or a group of consecutive scanning lines with the same count value by the counting means, and determining whether or not the order in which these groups appear is in a predetermined order. A screw cap bottle inspection method that determines the quality of the threaded part by any of the following methods. 2. The light shielding plate is provided between the light source and the screw cap bottle so as to block the upper part of the screw cap of the screw cap bottle, and the light source directs light from below the light shielding plate to the bottle mouth of the screw cap bottle. 2. The method of inspecting a screw-top bottle according to claim 1, wherein the light beam is configured to illuminate the bottle so that the light beam passes through both side walls of the bottle neck. 3 The light shielding plate is arranged between the light source and the screw opening,
The screw cap bottle is provided so as to block the top of the screw cap bottle, and the light source is configured to shine a light beam onto the bottle spout of the screw cap bottle from above the light shielding plate, and the light beam illuminates one side wall of the bottle spout. A screw cap bottle inspection method according to claim 1, wherein the screw cap bottle is transmitted through the screw cap bottle.