Robust stabilization of tone reproduction curves for the xerographic printing process

The problem of stabilizing a single color tone reproduction curve of a xerographic printing engine is considered. This problem is critical to ensure high-fidelity color printing. The control system uses a small number of actuators and a small number of measurements to stabilize the potentially high-dimensional tone reproduction curve. The goal is to minimize the overall least squares deviation of the tone reproduction curve from the ideal nominal one in the face of disturbances like material changes, temperature, humidity, and uncertainty in the system description. The control design consists of the steps of (1) determining a robust optimally performing static controller and (2) realizing the controller that utilizes only past measurements. Numerical simulations and experiments validate the efficacy of the controller.