Photo-Electric Sensor

A photoelectric product sensor is the most common method of giving a start signal. Alternatives to using a photoelectric sensor can be using a PLC, relay, or a mechanical switch. Any of these methods are well suited to trigger the labeler.

Different types of sensors can be used to detect the product. The product size, shape, and color should all be taken into consideration when selecting a product sensor. Physical limitations for mounting the sensor must also be considered.

Diffused Beam Sensor

This sensor emits a light, which reflects off of the product and is then detected by the sensor. The defused beam sensor does not require the use of a reflector. This sensor works well on products where there is an unobstructed area behind the product.

Retro-Reflective Sensor

This sensor requires the use of a reflector opposite of the sensor. The sensor emits a light, which is reflected off of the reflector and detected by the receiver in the sensor. When the product passes through the beam of light it interrupts the signal being received by the sensor, giving a signal to trigger the labeler.

Convergent Beam Sensor

This sensor is used the least of all the sensors listed. This sensor is color sensitive and must be mounted at close range to the area being sensed, normally within one inch. It is very useful in detecting large differences in contrast such as sensing a registration mark on a web.

Infrared Thru-Beam Product Detector

This sensor is comprised of an emitter and a receiver. Alignment of these components is critical. The through-beam detector is used to detect reflective products.

Fiber-Optic Sensor

Most of the sensors listed are available in a fiber-optic version. The sensors will operate in the same manner as described with the emitter and receiver mounted to the end of fiber-optic cables. This type of scanner is used when the standard unit is too large to mount in a restrictive area.

Mechanical Switch Interface

In certain applications it may be necessary to use a mechanical switch to trigger the labeling head. This is very useful in semi-automatic applications. A switch can be mounted in a fixture, which holds the product. When the product is placed in the fixture, it will trip the switch and trigger the machine. A foot pedal is also a common method used to activate the applicator in a semi automatic application.