Efficient charge neutralization with an ac corona ionizer

This paper discusses the problem of obtaining effective charge neutralization by an ac corona ionizer with airflow. The motion of ions and the neutralization of a charged object for different discharge frequencies and airflow velocities are investigated by a computer fluid model for positive and negative ions. The results of the investigation show that, in the region of ion transport, the quasi-neutralized charge distribution self-generated by positive and negative ions during charge neutralization can effectively transport the ions themselves from an ionizer to a charged object and significantly reduce both the unwanted fluctuation and dc offset in the potential of the object at a steady state, resulting in efficient and precise charge neutralization. Since the quasi-neutralization greatly depends on the relationship between the discharge frequency and airflow velocity, the control of the relationship may lead to better neutralization with an air-blowing ac ionizer.