Design of a printhead alignment sensor for a temperature varying environment

First findings are presented of an absolute position sensor for active alignment of printheads with respect to the printer frame over a distance of one meter. A string is stretched along the guidance serving as an absolute reference. The developed sensor measures the position of the printhead relative to this string. It is cheap and it is robust for temperature variations in the order of tens of degrees. The target accuracy is 1 mum over a range of about 2 mm. Although only one measurement direction is of interest for the application, it can actually be used as a 2D sensor. If an extra sensor is added to the same string, a 4D sensor can be created