GB2094469A

GB2094469A - A label detecting device

Info

Publication number: GB2094469A
Application number: GB8107349A
Authority: GB
Original assignee: GD Searle LLC
Current assignee: GD Searle LLC
Priority date: 1981-03-09
Filing date: 1981-03-09
Publication date: 1982-09-15

Abstract

A device is disclosed for detecting the presence or absence of a label on a container (d). A plurality of infrared sensors (a, b, c) are arranged to direct beams of infra-red radiation at containers (d) passing along a path and arranged to detect reflection of the beams from labels on the containers. The sensors produce a signal which depends on whether or not the beam is being reflected. A container reject device (f, g) is operable to direct containers along one of two paths in dependence on the signal produced by the sensors. <IMAGE>

Description

SPECIFICATION Label detecting device This invention relates to a label detecting device, and, in particular, to a device for detecting the presence or absence of a label on a container.

In accordance with the present invention there is provided a device for detecting the presence or absence of a label on a container, which comprises at least one infra-red sensor arranged to direct a beam of infra-red radiation at containers passing along a path and arranged to detect reflection of the said beam from labels on the containers, the said sensor producing a signal which depends on whether or not the beam is being reflected, and a container reject device operable to direct containers along one of two paths in dependence on the signal produced by the said sensor.

In the accompanying drawings, which show an embodiment of the invention: Figure 1 is a perspective view showing the device of the present invention; Figure 2 is a diagrammatic view of the device of the present invention; and Figure 3 shows in detail part of the container reject device.

Referring first to Figure 1, containers d, of which one is shown in Figure 1, travel along a conveyor and enter a detection zone in which a plurality of infra-red sensors, a, b and c are arranged. Each of these sensors continuously emits a beam of infra-red radiation which is intercepted by the container d as it passes through the detection zone. If the beam emitted by any one of the sensors strikes a label on the container the beam is reflected back to the sensor which emitted it and is detected by a suitable detecting element, for example a phototransistor mounted in the same housing as the beam emitter. If, in contrast, the beam strikes only the container itself and not a label thereon, such reflection as may occur will not be sufficient in magnitude to be detected by the phototransistor.In order to prevent the infra-red beam from one sensor being detected by the phototransistor of another sensor, each sensor is angled down slightly. This angle is such that the beam emitter and the beam detector of a given sensor are mounted at equal angles of incidence with respect to the surface of labels on containers passing in front of the sensor. The beam emitters may be of any suitable type, for example they may be gallium arsenide emitters.

Such emitters produce a high frequency modulated beam.

A container reject device is mounted downstream of the detection zone. The reject device comprises a blade g and a fluid pressure cylinder f, for example a pneumatic cylinder, which serves to move the blade g between the illustrated reject position in which it obstructs free passage of containers along the conveyor and a pass position in which it does not obstruct such passage. The cylinderfis connected to the sensors a, b and c in such a way that if a reflected beam is detected by any one of the sensors the reject blade is moved to its pass position, whereas if no reflected beam is being detected by any of the sensors the blade is in its reject position and serves to deflect containers into a reject box k.It will be appreciated that the device therefore operates in a fail-safe mode in which a positive signal indicating the presence of a label on a container is required to allow free passage of the container. If the device should fail for any reason containers will automatically be rejected.

The manner in which signals are provided to the cylinder fis shown in Figure 2. It will be seen from this that the sensors are connected electrically in parallei to a single control amplifier.

Thus, if any one of the sensors receives a reflected signal this will initiate the switching of a relay in the amplifier which will in turn produce an amplifier output signal. This output signal is fed, as indicated in Figure 3, to the coil of a pneumatic solenoid valve which controls a 5-port valve. This valve selectively distributes pressure to one or other end of the cylinder fvia two flow regulators.

Thus, the piston in the cylinderfis moved selectively to one or other end depending on whether or not a reflected signal is being detected by any one of the sensors.

In a preferred embodiment, the amplifier has a built-in variable delay unit, which can be varied to give a delay of up to 10 seconds duration in either of two modes. In the first mode the output signal from the amplifier is maintained for the pre-set delay after the amplifier has ceased to receive an input signal from the sensors. In the second mode the output signal of the amplifier is maintained for the pre-set delay after the amplifier has commenced to receive a signal from the sensors.

In either mode, the delay reverts to its originai state after the pre-set delay.

It has been found that the device of the present invention is capable of dealing not only with cylindrical containers but also with rectangular, square and irregularly shaped containers. It has also been found that the device is capable of detecting even labels where the paper is masked by the presence thereon of dark inks. Unlike some known label detection systems, labels can be reliably detected even if they do not extend very far around the container, for example if they only extend around 40% of the circumference. it is to be noted that the device requires no gating signal to initiate the sensors and can therefore handle containers that are not uniformly spaced on a conveyor, as long as there is a gap between them.

It is also to be noted that the device operates without any need to rotate the containers, as is required in some known label detection systems.

Finally, it should be noted that the device can be used as a multi-label scanner by using a plurality of sets of sensors at different heights, each set having its own amplifier.

1. A device for detecting the presence or

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Label detecting device This invention relates to a label detecting device, and, in particular, to a device for detecting the presence or absence of a label on a container. In accordance with the present invention there is provided a device for detecting the presence or absence of a label on a container, which comprises at least one infra-red sensor arranged to direct a beam of infra-red radiation at containers passing along a path and arranged to detect reflection of the said beam from labels on the containers, the said sensor producing a signal which depends on whether or not the beam is being reflected, and a container reject device operable to direct containers along one of two paths in dependence on the signal produced by the said sensor. In the accompanying drawings, which show an embodiment of the invention: Figure 1 is a perspective view showing the device of the present invention; Figure 2 is a diagrammatic view of the device of the present invention; and Figure 3 shows in detail part of the container reject device. Referring first to Figure 1, containers d, of which one is shown in Figure 1, travel along a conveyor and enter a detection zone in which a plurality of infra-red sensors, a, b and c are arranged. Each of these sensors continuously emits a beam of infra-red radiation which is intercepted by the container d as it passes through the detection zone. If the beam emitted by any one of the sensors strikes a label on the container the beam is reflected back to the sensor which emitted it and is detected by a suitable detecting element, for example a phototransistor mounted in the same housing as the beam emitter. If, in contrast, the beam strikes only the container itself and not a label thereon, such reflection as may occur will not be sufficient in magnitude to be detected by the phototransistor.In order to prevent the infra-red beam from one sensor being detected by the phototransistor of another sensor, each sensor is angled down slightly. This angle is such that the beam emitter and the beam detector of a given sensor are mounted at equal angles of incidence with respect to the surface of labels on containers passing in front of the sensor. The beam emitters may be of any suitable type, for example they may be gallium arsenide emitters. Such emitters produce a high frequency modulated beam. A container reject device is mounted downstream of the detection zone. The reject device comprises a blade g and a fluid pressure cylinder f, for example a pneumatic cylinder, which serves to move the blade g between the illustrated reject position in which it obstructs free passage of containers along the conveyor and a pass position in which it does not obstruct such passage. The cylinderfis connected to the sensors a, b and c in such a way that if a reflected beam is detected by any one of the sensors the reject blade is moved to its pass position, whereas if no reflected beam is being detected by any of the sensors the blade is in its reject position and serves to deflect containers into a reject box k.It will be appreciated that the device therefore operates in a fail-safe mode in which a positive signal indicating the presence of a label on a container is required to allow free passage of the container. If the device should fail for any reason containers will automatically be rejected. The manner in which signals are provided to the cylinder fis shown in Figure 2. It will be seen from this that the sensors are connected electrically in parallei to a single control amplifier. Thus, if any one of the sensors receives a reflected signal this will initiate the switching of a relay in the amplifier which will in turn produce an amplifier output signal. This output signal is fed, as indicated in Figure 3, to the coil of a pneumatic solenoid valve which controls a 5-port valve. This valve selectively distributes pressure to one or other end of the cylinder fvia two flow regulators. Thus, the piston in the cylinderfis moved selectively to one or other end depending on whether or not a reflected signal is being detected by any one of the sensors. In a preferred embodiment, the amplifier has a built-in variable delay unit, which can be varied to give a delay of up to 10 seconds duration in either of two modes. In the first mode the output signal from the amplifier is maintained for the pre-set delay after the amplifier has ceased to receive an input signal from the sensors. In the second mode the output signal of the amplifier is maintained for the pre-set delay after the amplifier has commenced to receive a signal from the sensors. In either mode, the delay reverts to its originai state after the pre-set delay. It has been found that the device of the present invention is capable of dealing not only with cylindrical containers but also with rectangular, square and irregularly shaped containers. It has also been found that the device is capable of detecting even labels where the paper is masked by the presence thereon of dark inks. Unlike some known label detection systems, labels can be reliably detected even if they do not extend very far around the container, for example if they only extend around 40% of the circumference. it is to be noted that the device requires no gating signal to initiate the sensors and can therefore handle containers that are not uniformly spaced on a conveyor, as long as there is a gap between them. It is also to be noted that the device operates without any need to rotate the containers, as is required in some known label detection systems. Finally, it should be noted that the device can be used as a multi-label scanner by using a plurality of sets of sensors at different heights, each set having its own amplifier. CLAIMS

1. A device for detecting the presence or absence of a label on a container, which comprises at least one infra-red sensor arranged to direct a beam of infra-red radiation at containers passing along a path and arranged to detect reflection of the said beam from labels on the containers, the or each said sensor producing a signal which depends on whether or not the beam is being reflected, and a container reject device operable to direct containers along one of two paths in dependence on the signal produced by the said sensor.

2. A device according to claim 1, comprising a plurality of sensors so arranged that at least one of the sensors detects any label on a container, irrespective of the orientation of the container.

3. A device according to claim 1 or 2, wherein the reject device comprises a member movable between a reject position in which it directs containers along a reject path and an accept position in which it directs containers along a path which represents acceptance of the containers.

4. A device according to claim 3, wherein the said movable member is in the reject position unless a signal is produced by the sensor or at leastone of the sensors.

5. Adevice according to claims 3 or 4, comprising an amplifier for receiving signals produced by the sensor or sensors and emitting an output signal in response thereto, and a pneumatic operating means arranged to receive the said output signal and be controlled thereby, the pneumatic operating means serving to operate the said movable member.

6. A device according to claim 5, wherein the amplifier is arranged to continue to emit the said output signal for a predetermined time after it has ceased to receive a signal from the sensor or sensors.

7. A device according to claim 5, wherein the amplifier is arranged to continue to emit to the said output signal for a predetermined time after it has commenced to receive a signal from the sensor or sensors.

8. A device according to any preceding claim, comprising a plurality of sensors or arrays of sensors arranged to detect a corresponding plurality of labels arranged at different heights on the container.

9. A device for detecting the presence or absence of a label on a container, substantially as herein described with reference to the accompanying drawings.