A system for drop detection of fluid drops ejected by a printing device includes a drop detector comprising a radiation source and radiation sensor for illuminating a region in which drops are ejected by a print bar and detecting radiation from the radiation source that is reflected by backscattering from the drops to the radiation sensor; and a controller for controlling the drop detector and the print bar, wherein the controller uses a signal output by the drop detector to determine whether nozzles of the print bar are operating properly.