We create a computer based numerical model to predict the color spectra of printed patches on dry toner electrophotographic printers. The goal of this research is to obtain a simplified model describing the input-output behavior of the printers based on the physical characteristics of the different printing process steps and the interactions between them. This leads to a better understanding of the factors that have an impact on printing quality. Furthermore, by modeling the non-linearities of the electrophotographic process, the prediction model will allow the creation of device calibration data with a minimal effort. In order to avoid the additional optical non-linearities produced by light reflections on paper (dot-gain), we have limited the present investigation to transparency prints. In its current version, the proposed model is capable of predicting the transmittance spectra of a printed monochrome wedge down to a mean deviation less than CIELAB ΔE* _ab = 1.5. The proposed simulation incorporates sub-models of the electrophotographic process shown in Fig. 1, such as the exposure of the photoreceptor, the generated electrostatic field, the toner's charge and diameter distributions, as well as the transfer and the fusing steps.