In one example, a printing system is described, having a conveyor belt, a first optical sensor, a second optical sensor, and a controller. The first optical sensor is located proximate to a first edge of the conveyor belt. The second optical sensor is located proximate to a second edge of the conveyor belt, wherein the second edge is on the opposite side of the conveyor belt to the first edge. The controller receives data related to optical detection of lateral movement of the conveyor belt from the first and second optical sensors, and causes a correction for the detected lateral movement of the conveyor belt in association with a print job of the printing system.