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 at the same time.
The movable sensor has a center array of sensors. This provides an 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 atypical 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 backside of the media (or media liner). Align the sensor to the middle of black marks or notches not in the center of the media roll to avoid web/gap sensing array.