JPH0469556A - Defect inspecting method for glass container - Google Patents

Abstract

PURPOSE:To automatically inspect a defect of glass container, dark-color container, etc., whose surface is bloomed according to the quantities of photodetection of respective photodetecting elements. CONSTITUTION:A glass bottle 3 is mounted on a rotary table and rotates on its axis. A light source device 1 is so arranged as to project projection light 2 containing infrared rays on the barrel wall part 3a of the bottle 3. A photodetector is arranged perpendicularly on a screen 5 and consists of many infrared- ray photodetecting elements Pi. Output electric signals 8 of the respective elements Pi based upon transmitted light 7 are inputted to an analog processing circuit Ai, whose output signal 10 is processed by a computer 9. The bottle 3 to be inspected is mounted on the rotary table and when the bottle 3 reaches a specific rotating speed, an inspection signal 20 is inputted to the computer 9. At the same time, the circuit Ai and computer 9 operate and whether or not there is the defect is decided in the computer 9. Consequently, the defect generated in the barrel wall part of the glass container, dark-color glass container, etc., whose surface is bloomed can be inspected automatically.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention provides a method for detecting defects that occur on the body wall of glass containers that are difficult to inspect with visible light, such as glass containers whose surfaces have been bloom-treated or dark-colored glass containers. Burns, bubbles.

This invention relates to a method for inspecting defects such as foreign objects (stones) in glass.

Here, Bloom treatment is used to remove Na ions near the surface using sulfur dioxide gas to prevent Na ions in the glass from eluting into the saline solution, such as Ringer bottles used to store physiological saline. The bloom-treated TC surface has a frosted glass-like appearance or a grape skin surface.
It's whitish. Dark-colored glass refers to glass that has low visible light transmittance and appears black.

(Prior Art) A means for automatically inspecting defects such as burn marks occurring on the body wall of a glass container is disclosed in Japanese Patent Publication No. 57 365374#! F Publication, Utility Model Publication No. 1983-+83854, and Japanese Patent Application Publication No. 1983-
It is described in Publication No. 109352 and the like. These all take advantage of the light transmittance of transparent glass containers or the light reflectivity of glass containers with smooth surfaces6, and include bloom-treated glass containers with surfaces that scatter incident light and visible light rays. It cannot be applied to dark-colored glass containers with poor transmittance.

There has been no known defect inspection method for bloom-treated glass containers.

<Problems to be Solved by the Invention> The present invention automatically detects defects occurring in the body wall of glass containers whose surfaces are bloom-treated (glass containers, dark-colored glass containers, etc.) that are difficult to inspect with visible light. The purpose is to provide a method for visually inspecting

(More Means for Solving the Problems) The method for inspecting defects in glass containers of the present invention is a method for inspecting defects in tζ glass containers, dark-colored glass containers, etc. whose surfaces are bloom-treated, and the glass containers are While rotating around the container, a diverging projection light containing infrared radiation and having relatively high parallelism was projected onto the container and was disposed parallel to the axis. The method is characterized in that the projected light transmitted through the container is received by a light receiver consisting of a row of a large number of infrared light receiving elements, and defects are determined based on the amount of light received by each light receiving element.

Defects can be determined based on the amount of light received by each light-receiving element as described above by using a plurality of defect-free reference glass containers.
A signal value E<1) based on the amount of light transmitted through a part without non-defect uneven parts such as gold marks or marks is stored in
The lowest value E of the signal value E(1) of each reference glass container
(i) Find the win and multiply it by a certain ratio E
(i) minx is set as the judgment reference value for each light receiving element, and the signal value based on the amount of light transmitted through the glass container to be inspected received by each light receiving element is compared with the judgment reference value. It is preferable to determine that there is a defect when the signal value is lower than the determination reference value.

(Function) Ordinary visible light is difficult to pass through bloom-treated glass containers due to scattering, but infrared light generally has a long wavelength, so
Infrared rays in the near-infrared region with a wavelength of 1.8 μm or more easily pass through the bloom-treated layer made of fine bloom particles, and therefore easily pass through the bloom-treated glass container, as shown in Figure 1. The transmittance of bloom-treated glass containers is almost equal to that of transparent glass containers.

It is not affected by the bloom processing layer.

However, when the wavelength exceeds 2.5 μm, the transmittance of the glass itself decreases. Therefore, by using an infrared light-receiving element 1, such as a PbS light-receiving element, which has sensitivity in the range of 1.8 to 2.5 μm, it is possible to inspect glass containers for defects without being substantially affected by the bloom treatment layer. .

Much the same can be said for dark-colored glass containers.

In FIG. 1, reference numerals 131 and 32 indicate the relationship between the transmittance and wavelength of a bloom-treated glass container and a transparent glass container that is similar except that it is not bloom-treated.

The light receiver is arranged parallel to the axis of the glass container and consists of a row of many infrared light receiving elements.

Glass NR? r is rotated around the axis and a relatively highly parallel diverging projection light containing infrared rays is projected onto this container. Defects can be detected.

However, even if there are no gaps or defects, if light passes through a glass surface that is curved and has an angle to the incident light, such as a shoulder, the amount of transmitted light will decrease.When passing through a glass surface with poor wall thickness distribution In this case, the transmitted light amount distribution deteriorates and dark areas appear.

Glass containers such as ringers have one opening (corresponding to the seam of the split mold) and a measuring mark (see symbol 6 in Figure 2).
There are also irregularities unrelated to defects, such as letters such as numbers indicating measurement values, that is, non-defect irregularities. In addition, as mentioned above, when light passes through a glass surface that curves at an angle to the incident light, such as a 62 shoulder, or a surface with a poor thickness distribution, the amount of transmitted light decreases in areas without defects such as openings, letters, etc. . Therefore, the judgment value for the amount of light received at abutments, letters, and areas without defects is:
′! It is necessary to set the amount of light to be smaller than the amount of light transmitted through the openings, characters, and parts of non-defective products.

As a means for this lζ, a plurality of 1, usually 4 to 5,
Using a defect-free reference glass container, a signal value E(i) is stored for each light receiving element P based on the amount of light received that has passed through a portion with no defect-free unevenness.

Since this signal value E(1) is slightly different for each reference glass container, the lowest signal value E(i) akin
seek.

The lowest signal value E in a larger number of standard glass containers
(i) Min should be determined, but since this requires considerable effort, the number of reference glass containers should be kept relatively small, and instead a constant coefficient K (usually 0.8 to 0.9
) is the lowest signal value E (i )min multiplied by t, E (
i) minx is regarded as the lowest value of each signal value E(i), and the value of C is set as the judgment reference value for each light receiving element Pi.

Since the parallelism of the projected light is relatively high, the amount of light received by each light receiving element Pi is mostly based on the transmitted light transmitted through the annular body wall portion located at the height level corresponding to each light receiving element Pi. The amount of light transmitted through the non-defective portion of each light receiving element Pi is based on the difference in light receiving characteristics of each light receiving element Pi, the thickness of each annular body wall portion, or the difference in axial slope, curved surface, etc. Each value will vary slightly depending on the difference in light transmittance and the difference in the distribution of transmitted light amount in the height direction based on the light source lens.

Therefore, the judgment reference values of each light receiving element Pi are slightly different from each other.

The amount of light received when one character passes through a defect or abutment is smaller than the amount of light received when a normal part passes due to scattering by the defect or three characters. , a signal value based on the amount of light received by each light receiving element Pi and a judgment reference value E (i
)minx, and this signal value is the judgment reference value E.
(i) When minx is lower than K, it can be seen that a non-defect uneven part such as a defect or 1 abutment 2 characters exists in front of the light receiving element tζ.

In order to prevent such non-defective irregularities from being detected as defects, the results of determining the signals from each light-receiving element are arranged vertically in the order of the light-receiving element P, and the results are analyzed for each time. When images are lined up horizontally and have a fixed appearance pattern, such as one character per opening or a measurement line, judging from their regularity and image characteristics, they are not considered defects, but there are patterns other than those mentioned above. In this case, the defect in the glass container can be determined by determining that the glass container is defective.

(Example) In FIGS. 2 and 3, l is a light source device, 2 is a projection light,
3 is a bloom-treated glass bottle. Light source device 1
emits a light beam 1a' containing infrared radiation. tungsten
A point light source 1a made of a filament, etc., and a light beam 1a
' is provided with a condenser and a lens 1b for converting the projected light 2 into divergent projection light 2 with relatively high parallelism.

The glass bottle 3 is placed on a rotary table 4, and is rotated around its axis by rotating the rotary table 4 by a motor (not shown). The light source device 1 projects light 2 onto the body of a glass bottle 3! ! ! It is arranged so as to project the portion 3a.

A screen 5 is disposed at a position slightly apart from the body wall 3a of the glass bottle 3, on the opposite side of the light source device. A light receiver P is disposed on the screen 5 in a vertical direction substantially along a plane passing through the light source and the axis of the glass bottle 3. The photoreceiver p i is constituted by a large number (n) of 128 infrared light receiving elements Pi in this embodiment. The infrared receiving element Pi is preferably made of a PbS element, but may also be made of a Ge solar cell.

Based on the transmitted light 7 (the output electrical signal 8 of each light receiving element Pi is
The signal is input to an analog processing circuit AI provided for each light receiving element Pi, and the output signal 10 of the analog processing circuit Ai is configured to be processed by a computer 9.

When the infrared light receiving element is composed of a PifJSPbS element, P
Since the bS element is of an electrical resistance type, the change in electrical resistance caused by light reception is converted into a current signal 8 by a constant voltage source 1, for example, a battery 11, as shown in FIG.

As shown in FIG. 4, the analog processing circuit Ai includes a preamplifier +2. A voltage amplifier 13 and a comparator 14 are arranged in series. Further, a digital/analog (D/A
) A converter 15 is provided.

The current signal 8 from the infrared light receiving element Pi is sent to the preamplifier 1.
After being converted into a voltage signal by D 2, it is input to a voltage amplifier 13 where it is amplified and input to one terminal of a comparator 14.
It is compared with the input signal 17 from the /A converter 15.

Visual inspection confirmed that there were no defects such as air bubbles. Place the first reference glass bottle 3 on the turntable 4, and repeat slight rotation and stop with one hand while checking that the light that has passed through the normal part enters the light receiving element. D/ in order from the smaller one (or the smaller one)
A data signal 16 is sent to the A converter 15, and the data of the D/A converter 15 when the output signal 10 of the comparator 14 changes is set as the signal value E(i) from the light receiving element Pi, and this is set as the current value. It is stored in the computer 9 as .

6 Perform the same process on the second reference glass bottle 3,
The obtained current tc value is compared with that of the first reference glass bottle 3, and the smaller one is set as the MIN value.

The same process is performed for the third and subsequent reference glass bottles 3, and the MIN value is compared with the MIN value, and the MIN value is updated to determine the minimum value E(i)+in. This minimum value E (i)w
For each D/A converter 15 of each analog processing circuit A1, multiply in by K (preferably a predetermined value between 0.8 and 0.9) and use the value E (i) + tnx as a criterion value. set.

After the above preparations are completed, the inspection is performed as follows.

When the glass bottle 3 to be inspected is placed on the rotating turntable 4, "
A "bottle present" signal 19 is input to the computer 9, and when the glass bottle 3 reaches a predetermined rotational speed, an inspection signal 20 is input to the computer 9. Simultaneously with the input of the inspection signal 20, each analog processing circuit Ai and the computer 9 operate, and the presence or absence of a defect is determined in the combination coater 9 for each annular portion at the height level corresponding to each light receiving element Pi.

In this case, as shown in FIG. 5, the output signal value of the light-receiving element Pi is lower in bubbles and uneven parts than in normal parts due to light scattering (tc), that is, based on that part (signal value E(i) Since E(i)minxK is smaller than the judgment reference value, the comparator 14 outputs a signal 10.

It appears as a black part in the figure.

In FIG. 5, the horizontal axis indicates time, and it is shown that one rotation of the glass bottle 3 takes 1925 units of time. The vertical axis corresponds to the height of the light receiver P, and the numbers indicate the number of each light receiving element Pi.

FIG. 5 is based on a printout of a pig that has been image-processed by computer 9, and is based on 22 and 2
The black parts of 3 correspond to the non-defect uneven parts of 1 joint and 1 character of the measurement line, respectively, and the black parts of symbol 24 are based on air bubbles.The reason why each part appears twice is due to the light source. 2 when the device is turned on the L side and when it is turned on the opposite side.
This is because the light receiving element Pi receives the transmitted light 7 twice.

Since the appearance pattern of the black parts 22 and 23 based on non-defect uneven parts is almost fixed, this is stored in the computer 9 and erased as a non-defect part. ” When the second largest one is detected, the computer 9 sends a “bottle reject signal” 21
Output. Also, depending on the shape of the black part 24, it can be determined whether it is caused by air bubbles or the like.

Note that when signal processing is performed using a reference glass bottle, the portion 1 where a black portion appears continuously horizontally, for example, the shoulder portion 3b of the bottle 3 (see Fig. 3), is connected to the analog processing circuit Ai of the corresponding light-receiving element P.
D/A change 11 to comparator 14! ! The input value 17 from the device 15 is set to O to be outside the inspection range.

(Effects of the Invention) The present invention has the advantage that it is possible to automatically inspect defects occurring in the body wall of glass containers, dark-colored glass containers, etc. whose surfaces have been subjected to bloom treatment.

Furthermore, the present invention as set forth in claim 2 is based on the first gold and one character.

The existence of non-defective uneven parts such as marks, differences in light receiving characteristics for each light receiving element, differences in light transmittance due to differences in wall thickness and slope of the glass container in the height direction, and differences in light transmittance in the height direction based on the light source lens. This has the advantage that the above inspection can be performed without being affected by differences in transmitted light quantity distribution, etc. (1).

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of the relationship between the wavelength of projected light and the transmittance of a glass container, FIG. 2 is an explanatory plan view of an example of an apparatus for carrying out the present invention, and FIG. FIG. 4 is a circuit diagram of an example of a signal processing device in the apparatus shown in FIG. 2, and FIG. 5 is a front view for explaining the apparatus shown in FIG. This is an example of an image including a defective part. 2... Projection light, 3 Glass container, P Photoreceiver Pi/light receiving element. plastic ~ hao

Claims (2)

[Claims] (1) In a defect inspection method for glass containers with bloom-treated surfaces, dark-colored glass containers, etc., while rotating the glass container around its axis, a relatively highly parallel diverging projection light containing infrared rays is emitted. The projected light transmitted through the container is received by a light receiver consisting of a row of a large number of infrared light receiving elements arranged parallel to the axis of the container, and based on the amount of light received by each light receiving element. 1. A method for inspecting defects in glass containers, characterized in that defects are determined by (2) Using multiple defect-free reference glass containers, the signal value E(i
), and the signal value E(i
), and the value E(i)min x K, which is obtained by multiplying this by a certain ratio, is set as the judgment reference value for each light receiving element, and the value of the light transmitted through the glass container to be inspected is determined. The signal value based on the amount of light received by each light-receiving element is compared with the judgment reference value, and when the signal value is lower than the judgment reference value for a portion other than the non-defect uneven portion, it is judged that there is a defect. Defect inspection method for glass containers.