In previous work, we observed that current flows through each system part (i.e. development roller, blade, and supply roller) in normal operation during roller rotation in a mono-component development system. Measurement of these currents was shown to be useful for determining toner charging and charge transfer mechanisms. A theoretical analysis of the process is presented and by comparing this with the experimental data, it is suggested that an effective bias is generated between the doctor blade and the development roller surface due to the toner charging. By measuring the surface potential on the development roller as it was rotated, charge trapping at the development roller surface was experimentally observed. This trapped charge was released by contacting with the supply roller. It was found that the surface characteristics of the development roller considerably affected the current and the charge retention of the surface. This is shown to result in a “residual voltage” that is related to the effective bias controlling the current flow.