Charge spectrometer for mono- and dual-component toner

One of the important parameters in electrophography is the electrostatic charge of the toner particles. However, until recently only the average charge-to-mass ratio of many particles could be measured. In the past few years advances have been made in developing new instruments for measuring the charge of individual toner particles. We have designed and built such a tool, a charge spectrometer, for use with both mono- and dual-component toner. We describe the instrument and its performance characteristics and give a few examples of its uses.