The substrate-advance sensor, also known as OMAS, is located under the third front platen slab from the right; only the top window can be seen.
It is composed of two parts: the sensor and its optics located under the platen and a PCI control board on the main electronics box. Both are connected through a ribbon cable that runs through the vacuum beam, by the right side plate, and into the electronics box.
The optical sensor detects the surface of the back of the substrate as it moves across the platen. The sensor is able to evaluate the exact movement of the substrate and communicate any small adjustments required by the system to move the substrate accurately.
The sensor window must be cleaned of dust and ink to work correctly. The cleaning procedure is described in the user guide, in the section ‘Clean the substrate-advance sensor window’.
During the substrate load, the printer detects that the substrate has reached the print platen when the substrate-advance sensor captures its image.
NOTE: The sensor cannot detect the surface of some substrates, such as plastic or very dark ones. In these
cases, the sensor must be disabled, and instead, the printer uses feedback from the drive roller encoder to
calculate the substrate advance.
