JP2807275B2 - Synthetic resin container thickness measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention measures the thickness of a synthetic resin container (hereinafter, referred to as a container) having a bottomed cylindrical shape for filling various beverage products. Related to the device.

[Conventional technology]

Recently, various beverage products have been sold in relatively large containers. The filling of the container with various beverage products is generally performed while the beverage product is kept at a temperature of about 85 ° C., and the container is closed at the time of filling or relatively quickly after filling. For this reason, when the beverage product in the container cools, the internal pressure of the container decreases, but in this case, if the thickness of the wall of the container is uneven and the strength of the container varies, the thickness of the thin portion is reduced. An inward depression may occur. This is more likely to occur especially in long large containers. To prevent this deformation, it has been considered to improve the strength by making the wall thickness uniform.

Here, since the container is made by a continuous automatic production line, a non-contact, non-destructive method is adopted as a method of measuring the wall thickness.

Conventionally, a non-contact, non-destructive method for measuring a wall thickness radiates inspection light of a specific wavelength to the wall surface of a container, receives the inspection light transmitted through the container wall surface at a light receiving unit, and converts the inspection light into an electric signal. Was. The inspection light in the PET resin container thickness measuring device is not affected by disturbance noise, and the response of the transmission amount of the inspection light to a change in the thickness of the PET resin is sensitive. Is used near 2.6 μm. As described above, since the inspection light is infrared light, the inspection light cannot be visually observed. Therefore, the position of the thickness measuring point of the container is calculated based on the apparatus dimensions and the positional relationship of the container. I was doing it. Further, the measurement point of the PET resin container is destroyed or closed, and the measurement point is located by detecting a change in the amount of inspection light.

[Problems to be solved by the invention]

However, locating measurement points in a conventional thickness measuring device requires measurement and calculation of a plurality of device dimensions, or calculation by destruction or closure of a PET-based resin container and detection of a change in light amount, which requires a great deal of time. There was a problem that it took time. Furthermore, since the measurement position is estimated by calculation and measurement as described above, there is a problem that accuracy is lacking.

The present invention has been devised in view of such circumstances, and emits a visible laser light having an optical axis coincident with the inspection light to the container together with the inspection light to measure the wall thickness. It is an object of the present invention to provide a thickness measuring apparatus for a synthetic resin container that visualizes an optical axis and can easily locate a thickness measuring point.

[Means for solving the problem]

The present invention provides an apparatus for measuring the thickness of the container by radiating inspection light on a wall surface of a transparent or translucent synthetic resin container having at least one end opened, and measuring the inspection light transmitted through the container. A light source unit for generating inspection light, a visible laser light source unit for generating visible laser light, a mixing mirror that reflects the inspection light, but transmits the visible laser light, A light emitter that emits a visible laser beam to a point to be inspected on the wall surface of the container in a state where their optical paths are aligned with each other, and a light receiver that receives the inspection light transmitted through the container facing the light emitter and converting the inspection light into an electric signal. And a lifting device for lifting and lowering one of the light emitter and the light receiver, and inserting the same into the container, wherein the mixing mirror includes the inspection light and the visible laser light. And configured to direct the projector in a state of being matched optical axis of each other.

[Action]

The inspection light generated at the light source unit and reflected by the mixing mirror and the visible laser light generated at the visible laser light source unit and transmitted through the mixing mirror are guided to the projector with their optical axes aligned. The inspection light emitted from the projector to the same point of the container and transmitted through the container is converted into a corresponding electric signal by the light receiving unit. For this reason, the optical axis of the inspection light is visualized by the visible laser light emitted to the measurement point together with the inspection light, and the point at which the inspection light passes through the container, that is, the measurement point, can be easily and accurately located by visual inspection. Can do it.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic sectional view of an apparatus for measuring the thickness of a synthetic resin container according to the present invention. In FIG. 1, a thickness measuring device 1 for a synthetic resin container includes a light source unit 11 for generating an inspection light 12;
Visible laser light source section for generating visible laser light 22
A mixing mirror 31 for compounding the inspection light 12 and the visible laser light 22 to form a composite light C having the same optical path and the same optical path, and radiating the composite light C to the wall surface of the container 2 And a light receiver 51 for detecting only the inspection light in the composite light C transmitted through the container 2.

The light source unit 11 includes a light source 13 and a concave mirror positioned above the light source so as to face the mixing mirror 31 via the light source 13.
14 and a chopper 15 located on the side (right side in the illustrated example) of the light source 13. As the light source 13, for example, a light source that emits infrared light as measurement light such as a nichrome line is used. It is preferable to use infrared light having a wavelength of 2 to 5 μm, preferably around 2.6 μm. This is because the use of infrared light having a long wavelength lengthens the optical path formed by the lens system and the light guide section described later becomes longer, which causes a practical problem in terms of the device configuration, and, for example, 15 to 18 μm. This is because infrared light requires a black-body furnace and is expensive, thus avoiding difficulties such as that.

The concave mirror 14 is for condensing infrared light from the light source 13 and making it incident on the mixing mirror 31.

The chopper 15 is used for chopping the light reflected by the concave mirror 14 and traveling to the mixing mirror 31 so as to form an intermittent shape (that is, a crossing waveform). This chopping causes a drift and an offset due to the characteristics of a photoelectric conversion element provided in the photodetector 5 described later, and is necessary for removing these fluctuation factors and performing highly accurate measurement. For this purpose, the waveform is temporarily converted to a crossing waveform to cancel the drift and offset, and then converted to DC again. As a form of the chopper, an electric type for chopping an electric signal given to the light source 13 and a constant light emission from the light source 13 as in this embodiment, and the light is transmitted to the chopper plate 16 by the motor 15 at a predetermined rotation speed. A mechanical type that rotates and intermittently shields light is considered.

The visible laser light source unit 21 is for causing the visible laser light 22 to be incident on the surface of the mixing mirror 31 opposite to the surface on which the inspection light 12 is incident. The visible laser light to be used can be appropriately determined according to the optical characteristics of the mixing mirror 31 described later. The laser that generates visible laser light can be determined according to the wavelength of the visible laser light to be used. For example, a semiconductor laser can be used to generate visible laser light having a wavelength near 670 nm.

The mixing mirror 31 is used for the inspection light 12 incident from the light source unit 11.
And has an optical property of transmitting visible laser light 22 incident from the visible laser light source unit 21. FIG. 2 is a view showing the optical characteristics (transmittance) of the mixing mirror 31 when the wavelength of the inspection light 12 is 2.6 μm and the wavelength of the visible laser light is 670 nm. In FIG. 2, the transmission amount of the mixing mirror 31 is almost 0 in the wavelength range of the inspection light 12 (2.6 μm = 2600 nm), showing high reflectivity, and the transmission amount in the wavelength range of visible laser light (670 nm). It shows permeability although it is a few percent. Therefore, as shown in FIG. 1, the inspection light 12 incident on the mixing mirror 31 is reflected, and a part of the visible laser light 22 is mixed with the mixing mirror 31.
The composite light C is combined with the inspection light transmitted through the mirror 31 and reflected by the mixing mirror 31 to form a composite light C.

The light projector 41 includes a light emitting guide part 42, an incident reflecting mirror 43 provided above the light emitting guide part 42, an emitting reflecting mirror 44 provided below the light emitting guide part 42, and a light emitting guide part 42. And a driving device 45 for moving up and down. Mixing mirror
The composite light C compounded by 31 is reflected by the incident reflecting mirror 43 and guided inside the light emitting guide section 42 to the emitting reflecting mirror 44,
The light is reflected by the emission reflecting mirror 44 and is projected toward the wall surface of the container 2. Therefore, the inspection light and the visible laser light are
And the inspection light whose optical axis is visualized by the visible laser light can be visually recognized.

The light receiver 51 is located on the exit optical axis of the exit reflector 44 of the projector 41 and is opposed to the projector 41. This receiver
51 includes an interference filter 52 and a photoelectric conversion element 53.
The interference filter 52 detects only the inspection light 12 from the composite light C transmitted through the container 2 by combining with the spectral characteristic of the photoelectric conversion element 53, and blocks other unnecessary wavelengths of disturbance noise and visible laser light. . FIG. 3 is a diagram showing the transmittance of the interference filter 52 when the wavelength of the inspection light is 2.6 μm. The interference filter 52 has a filter characteristic having a peak at 2.6 μm.

The photoelectric conversion element 53 can be used at room temperature, and preferably has a peak spectral characteristic at a wavelength of 2 to 5 μm corresponding to the inspection light in order to improve the SN ratio. As such a photoelectric conversion element, a PbS (lead / sulfur) photoelectric conversion element can be used. FIG. 4 is a diagram showing the spectral characteristics of the photoelectric conversion element 53 when the wavelength of the inspection light is 2.6 μm, as in FIG. 3, and has a sensitivity of up to 3.1 μm with a peak at 2.5 μm. Therefore, by combining the interference filter 52 and the photoelectric conversion element 53, the inspection light 12 transmitted through the container 2 without being affected by the disturbance of the entire visible light including the visible laser light 22 (670 nm) is received by the light receiving device 51. Can be received. The signal converted by the photoelectric conversion element 53 is subjected to arithmetic processing in an electric signal processing system (not shown) to indicate the thickness of the container.

The arrangement position of the light receiver 51 is set in advance to a position where the light projector 41 descends to measure the wall thickness.

 Next, a series of measurement operations will be described.

First, the container 2 to be measured is held by container holding means (not shown). Next, the projector 41 is moved by the elevating device 45.
Is lowered and inserted into the container 2. After the projector 41 stops at the predetermined measurement position, the inspection light 12 is generated from the light source unit 11,
At this time, the inspection light 12 is chopped by the chopper 16. The inspection light 12 enters the mixing mirror 31.
On the other hand, visible laser light 22 is emitted from the visible laser light source unit 21 to the surface of the mixing mirror 31 on the side opposite to the side on which the inspection light 12 is incident. Then, in the mixing mirror 31, the inspection light 12 is reflected, and the visible laser light 22 is partially transmitted, so that the inspection light 12 and the visible laser light 22 are combined to form a composite light C having the same optical axis. The light enters the reflecting mirror 43 for incidence of the light projector 41 and is reflected. The composite light C travels through the light emitting guide section 42, is reflected by the output reflecting mirror 44, and irradiates the wall surface of the container 2. At this time, since the composite light includes the visible laser light 22, the optical axis of the inspection light 12 applied to the container 2 is visualized,
The thickness measurement point is easily confirmed. The composite light C transmitted through the container 2 enters the light receiver 51. Here, of the composite light C, unnecessary wavelengths of disturbance noise and visible laser light other than the inspection light 12 are cut off by the interference filter 52, and only the inspection light 12 is converted into an electric signal by the photoelectric conversion element 53. The thickness of the container is obtained by arithmetic processing by means. In addition, the container is subjected to the above-described measurement while being normally rotated, and the thickness at each rotational position of the container 2 (that is, the circumferential position of the container 2) is inspected, and the thickness distribution in the circumferential direction is obtained. Further, by providing a plurality of measurement points in the axial direction of the container 2, the thickness distribution in the axial direction can be obtained.

In the above embodiment, the case where the light emitter 41 is inserted inside the container 2 and the light receiver 51 is arranged outside the container 2 has been described, but the present invention arranges the light emitter 41 outside the container 2,
The light receiver 51 may be inserted into the container 2.

〔The invention's effect〕

According to the present invention, since the inspection light is combined with the visible laser light and applied to the container to measure the thickness, the optical axis of the inspection light is visualized, and the point at which the inspection light passes through the container, that is, the measurement point The effect is that the positioning of the container can be accurately performed in the container.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic sectional view of a thickness measuring apparatus for a synthetic resin container of the present invention, and FIG. 2 is a wavelength of a mixing mirror used in the thickness measuring apparatus for a synthetic resin container of the present invention. Diagram showing characteristics, third
FIG. 4 is a wavelength characteristic diagram of an interference filter used in the synthetic resin container thickness measuring device of the present invention, and FIG. 4 is a spectral sensitivity characteristic diagram of a photoelectric conversion element used in the synthetic resin container thickness measuring device of the present invention. is there. DESCRIPTION OF SYMBOLS 1 ... Thickness measuring device, 2 ... Container, 11 ... Light source part, 21 ...
… Visible laser light source, 31… Mixing mirror, 41…
... light emitter, 51 ... light receiver.

Claims (1)

(57) [Claims] An apparatus for radiating inspection light to a wall surface of a transparent or translucent synthetic resin container having at least one end opened, and measuring the thickness of the container by measuring the inspection light transmitted through the container. In, a light source unit for generating inspection light, a visible laser light source unit for generating visible laser light, a mixing mirror that reflects the inspection light but transmits the visible laser light, and the inspection light A light emitter that emits the visible laser light to a point to be inspected on the wall surface of the container with the optical paths thereof aligned with each other, and receives the inspection light transmitted through the container facing the light emitter and converts the light into an electric signal. A light receiving device, and a lifting device for lifting and lowering one of the light emitting device and the light receiving device and inserting the light into the container, wherein the mixing mirror includes the inspection light and the visible laser light. Mutual thickness measuring device of a synthetic resin container, characterized in that leads to the projector in a state of being matched optical axis.