Sick ML20 markless label sensor

Though used like a print mark sensor, the Sick ML20 sensor requires no optical marking on the package, instead detecting a taught-in design pattern. In future, the label on beverage bottles or chocolate bars and packaged chips can be in the right spot even without a registration marking.

The ML20 uses a novel method for detecting contrast patterns. In the process, the sensor is taught a pattern sequence, eg, the graphic images or lettering, which is then detected at a scanning rate of up to 7 m/s, resulting in the output of a switching signal. Even if the labels have a complex design or the machine is operating at high speed, the ML20 detects nearly any pattern with accuracy and stability.

The metal housing of the sensor provides a high level of ruggedness, and it is easy both to integrate in machines and to commission. The sensor works reliably even if the image patterns are intricate or the process varies.

When changing label or foil reels, the sensor avoids unnecessary cutting loss and waste, since pattern recognition is active right away, enabling use of the material starting immediately after the beginning of the reel. In some packaging processes, for instance when labelling bottles, there are additional savings of the additional material previously used exclusively for the print mark. The markless technology allows savings up to 5% of material per label.