Statics of pin corona charger in electrophotography

Statics of a pin electrode in a pin-to-plate system has been investigated to utilize the system for the new low ozone charger and to clarify the fundamental mechanism of bead carry-out in the two-component magnetic brush development subsystem of electrophotography. The electrostatic force in the system was measured and numerically calculated with a static unipolar model. Calculated voltage-current characteristics qualitatively agreed with those measured. Electrostatic force was also measured and calculated. Although extremely small electrostatic pull force was induced if discharge did not take place, the force became repulsive and relatively large when the corona discharge took place. Force in negative corona was almost the same as in positive corona. Calculated force without discharge agreed with the measured but the calculation did not simulate repulsive characteristics at corona discharging. Convection of air must be included in the model.