Sensing objects for printing

A printing apparatus including a conveyor capable of moving an object in a process direction, a drop ejection device, a sensor array that substantially spans the conveyor in a cross-process direction that is perpendicular to the process direction, the sensor array being configured to detect a position of the object in the process direction and cross-process direction, and a controller configured to receive position data about the object from the sensor array and to cause the drop ejection device to deposit fluid droplets on the object based on the position of the object on the conveyor.