Modeling of ozone emission by a corotron used in electrophotography

The generation of ozone in a stable regime of DC corona discharges at thin wires is modeled to provide data that can be utilized for the design of the charging and transferring devices of electrophotography, such as corotrons or scorotrons, with respect to reducing the ozone emission. The results of a theoretical investigation show the following: (1) Although the rate of the ozone emission is nonlinear with respect to the discharging current, it can be assumed to be approximately linear within the usual design and operating conditions of corotrons. (2) In the case of the positive corona, ozone is formed just at the surface of the discharge wire, but on the contrary, in the case of the negative corona ozone is formed about 0.1 mm from the wire. This yields the result that the ozone formation rate in the negative corona shows low dependence on materials used for the corona discharge wire but the rate in the positive corona is highly dependent on the wire materials. (3) The ozone formation rates are very small far from the discharge wire for both positive and negative discharges. This calculated result also supports the experimental evidence that the effect of materials used for the shield electrode is small for both positive and negative discharges.