Atmospheric pressure corona electric discharges are important components of electrophotographic (EP) printing technologies for charging surfaces and photoconductors. A typical corona discharge consists of a wire biased with dc potential of 100's V plus a few kV of ac bias. An electric discharge is produced around the corona wire from which electrons drift along the applied electric field to charge the underlying surface. This reduces the voltage drop across the gap which then terminates the discharge. In printing this underlying surface is continuously moving during charging. As a result, the corona discharge is re-ignited by the increased voltage drop provided by the incoming uncharged surface. To aid in development of these devices, an investigation based on first principles, multi-dimensional computer modeling has been conducted. We found that the uniformity of the summation of these charging cycles is sensitive to the conductivity, dielectric constant and speed of the moving surface, and the voltage waveform. Parametric results for charging of surfaces while varying these parameters will be discussed.