The Mechanism of Single Component Development with Several Insulating Magnetic Toners

Abstract

In order to clarify the development mechanism of insulating magnetic toners, we devised an experimental method, to be referred to as “Potential Decay” method, where one measures how a D. C. potential of an aluminum drum, initially given through connecting a charged capacitor, will decay via toner particle motion caused by the developer roll revolution.
The experiment was made on several kinds of toners, including 4 commercial ones, and following results were obtained;
(1) Without toner particle motion, very little potential decay was observed.
(2) Irrespective of insulating property of the drum surface, the effect of supplying fresh toner particles by the toner layer movement has major contribution to the potential decay.
(3) Even when the developer roll surface was insulated, only minor changes in the decay characteristics were observed for the measured two sampples. The following were inferred from the above results ;
(1) Charge injection from the developer roll to the toner particles has a minor contribution to the toner charge necessary to the developing process.
(2) At least for those two samples, main part of the toner charge is due to mutual friction among the particles.
(3) The charge enhancement model proposed by Nelson is not to be completely discarded.