Corona charging of organic photoreceptors (OPCs) has been characterized by the measurement of the time-dependent charging current. With this experimental technique, we have investigated the quantity and the dynamics of charging for times greater than the charger time constant (∼0.08 s). With a generic near-infrared sensitive OPC, we observe significant depletion of trapped charge during corona charging. The trapped charge sources are light exposure prior to charging as well as thermal generation with an activation energy of ∼1 eV. In addition, exposure during charging, with the corona-emitted light, produces a steady-state offset current. An OPC sensitive to visible light exhibited much less trapped charge, and thermal charge generation did not occur. This methodology provides a means of quantifying these effects and understanding the interactions of the OPC with the charging and exposure systems in an electrophotographic printer.