Sensor head for a colour proofing apparatus

摘要

A sensor head (10) for a colour proofing apparatus, comprising a light source (24) for illuminating a measurement location (38) on a surface of a proof substrate (14), and a light capturing element (22) arranged to capture light that is reflected from said measurement location (38), characterized in that the sensor head (10) has a ring member (48) that surrounds the light source (24) and the light capturing element (22) and is slidably guided in the sensor head and adapted to be projected towards the substrate (14) into a position where it engages a stop (52) that is fixed relative to the light source (24) and the light capturing element (22).