Charge elimination method for a charged roll using a passive type ionizer with an air assist

The charge elimination method for moving charged objects was investigated using a passive type ionizer with an air assist to effectively eliminate the static charge generated at high speed by the roll-to-roll process. The passive ionizer has a grounded needle placed horizontally with respect to the moving charged roll and an air hole to eject an air flow to transport the ions from the grounded needle. The passive ionizer releases ions from the grounded needle electrode when the electric field at the tip of the grounded needle exceeds the corona inception condition. The experimental set up is composed of a moving charged roll, the passive ionizer and surface voltmeters for evaluating performance. The charge elimination current I(e), which corresponds to the amount of ions produced per second was measured for various movement speeds and charge potentials of the charged roll. Supply of the air flow beneath the needle electrode increased I(e) because the ions were effectively transported to a place where the charge elimination of the roll did not affect the corona onset condition. The difference in charge elimination performance between the proposed ionizer and a commercial active ionizer was clarified in terms of I(e) and the charge elimination rate.