Registration sensors 

SICK Contrast sensors detect minimum contrast levels at maximum speeds, such as print marks on foil, packaging and print products. They detect small differences in grey values between mark and background on matte, gloss or transparent surfaces.

Luminescence sensors react to luminescent pigments, which are activated by the UV light source in the sensor. The sensors emit UV light with a wavelength of approx. 375 nm. Fluorescent substances convert the UV light into long-wave visible light. The light reflected in this way is received and evaluated by the luminescence sensor. Luminescence sensors with a blue LED (approx. 480 nm) are particularly suited for red luminescent marks.

These sensors combine the sender and receiver in a single housing. This ensures very reliable detection. The distance between the sender and the receiver is fixed, defined by the housing shape, and is described as the "fork width." Even very slight differences in light attenuation are detected, thanks to tightly focused light emission and high detection accuracy. Simple installation and high immunity to ambient light are just two of the advantages offered by fork sensors.

Color sensors function using a special three-color method. They cast light (red, blue, green) on the objects to be tested, calculate the chromaticity coordinates from the reflected radiation and compare them with previously stored reference tristimulus values. If the tristimulus values are within the set tolerance range, a switching output is activated.

The array sensor operates according to the scanning principle. It detects even the slightest grey value differences within its field of view. The positioning of, for example, a web of paper on the basis of the web edge or using a contrast line is merely one application amongst many examples. Widths, diameters and gaps can also be detected. The extremely compact, rugged metal housings permit their use in highly restricted or problematic locations.