An additive manufacturing system for printing a three-dimensional part, which includes one or more electrophotography engines configured to develop layers of the three-dimensional part, a rotatable transfer belt configured to receive the developed layers from the electrophotography engine(s), a detector configured to measure powder densities of the developed layers on the rotatable transfer belt, and to transmit signals relating to the measured powder densities to a controller assembly, and a printing assembly configured to receive the developed layer from the rotatable transfer belt and to print the three-dimensional part from the developed layers.