Toner charge is very important in electrophotographic printing process. Many studies on toner charging mechanism have been carried out. However, understanding of toner charging characteristics is not yet sufficient. Toner charge distribution is measured by E-SPART (Electrical Single Particle Aerodynamic Relaxation Time) which can measure and analyze the size and the charge of respective toner. The measured toner is of a crushing type. Charging is carried out as follows: the toner is mixed with carriers in a bottle and mixed by the rotation of the bottle. Average toner charge of each channel of the toner diameter is estimated. It is found that the average toner charge is proportional to the square of toner diameter and shows a saturation as the diameter increases. The experiment of adding the toner after the toner is charged to nearly stationary is carried out. It is found that toner charge distribution becomes a new value due to charge exchange between the toner and the toner/carrier.
Y. Hoshino, Y. Ando, H. Yoshida, Y. Nakamura, S. Kiatkamjornwong, "Toner Charging Characteristics in the Rotation Mixing System of Toner and Carrier" in Proc. IS&T Int'l Conf. on Digital Printing Technologies (NIP18), 2002, pp 284 - 286, https://doi.org/10.2352/ISSN.2169-4451.2002.18.1.art00070_1