Abstract: Devices and techniques that include use of a capacitive sensor to permit an OVJP print head to orient itself relative to conductive or dielectric traces on a printing substrate are disclosed. Such a sensor enables real-time measurement and closed-loop control of print head position with respect to substrate traces. This enables, for example, micron scale resolution in a dimension transverse to printing while permitting both the substrate and movement of the OVJP tool to scale to larger sizes than are achievable using conventional techniques and systems.