Embodiments of the disclosed subject matter provide a device having a print head that includes a micronozzle array of depositors to deposit a material on a substrate. A reflective optical device may reflect a signal output by at least one optical sensor, and to reflect the signal from a surface of the substrate to the optical sensor. A processor may determine a distance between the optical sensor and the target surface of the substrate. The device may include one or more actuators coupled to the at least one print head to move the print head relative to an internal reference frame and adjust a position of the print head to the substrate. The sensor may be fixedly coupled with a mount to the internal reference frame. The print head may be configured to move independently of the optical sensor in at least one axis of linear or rotational motion.