The movable sensor is a dual-function sensor. It provides transmissive (sees through media) and reflective media sensing. The printer can use either sensing method, but not both simultaneously.
The movable sensor has a center array of sensors. This provides adjustable transmissive web (gap) sensing to positions that match legacy Zebra desktop printer sensor locations and positions in between. This also provides for use of some non-standard media variations or irregularly-shaped media.
The movable sensor allows the printer to use media with black marks or notches (holes through the media) on the back side of the media (or media liner). The sensor aligns to the middle of black marks or notches not in the center of the media roll to avoid web/gap sensing array.