Simulation of print quality (PQ) defects is the process of artificially adding structures to an image that when printed will have the appearance of real artifacts. Simulated PQ defects can be used in a variety of types of diagnostic printer documentation, in the development of test pages for PQ defect diagnosis, in the investigation of the perception of PQ defects, and in the development of algorithms for autonomously identifying PQ defects. We develop a general framework for PQ defect simulation, and apply it to the simulation of three different classes of PQ defects associated with color laser printers: defects of uniformity, random marks or repetitive artifacts, and color defects. Each defect is simulated by a geometrical model, or by a scanned sample prototype. The parameters of the model are estimated from actual PQ defect samples. We demonstrate the capability to generate photo-realistic simulations of a total of 9 different defects.