Printing System Models

The xerographic printing process is a unique discipline that incorporates domainspecific ideas from physical sciences to engineering. Developing a complete model of the printer is very difficult and can limit its use for analysis purposes. We therefore present a nonlinear model of the printing system with reasonable abstractions of key elements of the digital color printing processes and yet retain the simplicity necessary to study the effects of control techniques on each of these processes. We first develop the underlying physics of the processes used for developing a colored dot that is fundamental to the creation of digital images for the color CMYK process. The process models are then cascaded in sequence where the output of one process model becomes the input to the next one. The dot spread is then modeled using a halftoning strategy and modulation transfer functions of the key segments of the electrophotographic process (EP). These models are used for designing feedback controllers for each of the major subsystems, such as controllers for generating multidimensional profiles, to understand their interactions, to manage the complexity of the system through careful design of control loops, and to achieve the overall system objective. We present the transformations that an electronic image goes through, before being reproduced on paper using analytical abstractions of the printing processes.