GB2131989A - Apparatus for identifying production codes on articles - Google Patents

Abstract

In apparatus for identifying the production code on articless, e.g. the base of a glass bottle, light reflected or refracted from the surface of the article is transmitted to a light beam detector, e.g. the phototransmitter (26), via a bundle of light-transmitting fibres (16) contained in a fibre optic guide (14). The signal output from the phototransmitter is amplified and processed to give usable electrical signals, which are interpreted by a code reader. <IMAGE>

Description

SPECIFICATION Apparatus for identifying production codes on articles This invention relates to an apparatus for identifying production codes appearing on articles, such as on glass bottles.

Many articles of commerce are produced on machines, several of which may be working in parallel and supplying their products onto a com mon production line. These machines may on occasion develop defects and provide products with faults onto the production line. Since these machines often work at high speed, a large number of faulty products may be on the production line, divorced from the defective machine, before the latter is remedied. In the past much manual labour has been employed to inspect products on such lines and to remove the faulty articles.

As industry becomes more sophisticated, products are now often coded with various marks to enable the machine on which they were produced to be readily-identified. Apparatus has been developed in some industries for automatically reading these codes to enable corrective action over faults to be speedily taken.

An example is the production of glass bottles, where a large number of glass bottle moulding machines are simultaneously supplying moulded bottles onto a conveyor which subsequently transports them to a lehr for annealing. It is common practice to mark the moulds in some manner so that the bottles they produce are unique - typically each mould cavity includes an area which moulds a cavity, or mould number onto the bottle base. This number (or other code if employed) is normally provided as a marking on the bottle base which is in addition to the normal ring of stippling present around the periphery of the base of such bottles.

Cavity numbers can be coded onto the base of glass containers by incorporating the code in the stippling itself. For example, using a binary notation, the presence of a stippling mark may be interpreted as a "1" and the absence of such a mark (from a position where one would otherwise expect such a mark to be) as a "0", and a code built up in this fashion.

It is not easy to read such codes automatically without error and at a speed compatible with the container forming production line. Reading is typically accomplished electro-optically, and normally requires relative movement of the container and an electro-optical detector (e.g. a phototransistor) so that the detector scans the code whereafter the results of the scan are processed electronically and decoded to provide the decimal cavity number.

In our Patent Application NO :8008479 we have described a system for identifying a production code appearing on an article which includes light beam detection means responsive to light from a source of illumination and which has been reflected or refracted from a production code on the article, and means responsive to the light beam detection means for providing a code signal in dependence upon the light intensity detected, the code signal or the absence of a code signal being utilised to provide a representation of the production code. In that application we have described the use as a light beam detector of a linear photodiode array camera, which detects light refracted by the stippling.

The use of a linear photodiode array camera has some disadvantages. For example, it is necessary to mount the camera above the container, e.g. a narrow-necked bottle, and focus the camera through the container in order to scan the base ofthe bottle carrying the production code. This may not be possible with all containers. Secondly, the stippling on the container base forming the production code has to be illuminated from the bottom of the container, and the degree of illumination or contrast reaching the camera is somewhat dependent on the characteristics of the base of the container. If, for example, the base is of uneven thickness then problems arise in reading the code. Thirdly, linear photodiode array cameras are rather expensive. A fourth disadvantage of the use of such cameras is that their use is not easily applicable to non-round containers.It is an object of the present invention to provide means for identifying production codes on articles, particularly glass containers such as bottles, which is simple to set up and operate and does not suffer from the difficulties mentioned above.

In accordance with the present invention, in apparatus for identifying a production code on an article, light reflected or refracted from a surface of an article carrying a production code is transmitted to a light beam detector via a bundle of lighttransmitting fibres.

Preferably the production code is illuminated from a source of illumination via a bundle of light transmitting fibres.

The present invention thus makes use of what are known as fibre optic components, each of which consists of a number of fibres, having a core clad with a material of lower refractive index, each transmitting a point of light from one end to the other. The components used in this invention are preferably non-coherent bundles of fibres.

In its application to glass bottles, the apparatus of the invention is used by illuminating the production code on the bottle, which is preferably formed of stippling on the base of the bottle, but may be formed, by stippling or otherwise, on the heel or any other convenient place on the bottle, and detecting the light which is reflected or refracted form the bottle. The presence of stippling causes the light to be reflected/refracted differently from a plain glass wall or surface, and this difference is detected and used, preferably electronically using the storage and decoding system described in our Patent Application No: 8008479, to identify the source of the container.

The container is suitably illuminated through a slit formed in a plate on which the container is rotated if it is round (and the production code appears on a circle or part thereof) or if it is non-round (e.g. square or rectangular in section) the container may be passed in linear fashion over a slot through which light is beamed. The slot assists in concentrating the light impinging on the container so as to illuminate only one part of the code at a time, e.g. one stipple.

Two different methods of operation in accordance with the invention will now be described with reference to the accompanying drawings, in which: Figure 7 is a diagrammatic illustration of a retroreflective system of operation; Figure 2 is a diagrammatic illustration of a refactive system of operation; and Figure 3 is a diagram illustrating the principle behind the operation illustrated in Figure 1.

With referenceto Figure 1, light is transmitted from a source 10 up one leg 12 of the Fibre optic guide 14. The two legs 12, 16 of the Y guide are meshed together in a random fashion and configured as a slot 18. The light is transmitted up from the slot and onto the base of a bottle 20 having a production code 22 formed the stippling and rotating on a slotted plate 24 so that the light from slot 18 impinges radially on the container. Aflat portion of the base (a gap between stipples) will reflect light back into the slot 18 and hence down the other leg 16 of the Y guide for signal processing. If light is transmitted onto a stipple, the curved nature of the stipple will tend to scatter the light and hence very little light will be reflected back into the slot for data processing.This is shown in more detail in Figure 3.

Thus, as the bottle is rotated the gaps and stipples will be interpreted as "light reflected" or "no light reflected". These varying levels are detected by means of a photo-transmitter 26 mounted onto the Y guide. The small signal output from the photo transmitter is then amplified and processed in order to give useable electrical signals. These signals can then be interpreted by a code reader which could be a microprocessor unit or a system as described in our Application No: 8008479.

With reference now to Figure 2 light transmitted from a fibre bundle 30 mounted above a bottle 32 is transmitted down through the bore of the bottle onto the base 34. The light will shine through the glass and down through the slotted dead plate 36 of a glass forming machine onto the fibre optic receiver 38. A stipple will bock the light path through the glass and the light falling onto the receiver will be reduced. The differing light levels are processed in a similar fashion to that described in connection with Figure 1.

Claims (4)

1. Apparatus for identifying a production code on an article, wherein light reflected or refracted from a surface of an article carrying a production code is transmitted to a light beam detector via a bundle of light transmitting fibres.

2. Apparatus as claimed in claim 1 wherein the production code is illuminated from a source of illuminaton via a bundle of light transmitting fibres.

3. Apparatus as claimed in claim 1 or 2 wherein said bundle of fibres is a non-coherent bundle of fibres.

4. Apparatus as claimed in claim 1, substantially as described with reference to the drawings.