Abstract
Graininess of electrophotographic images can be improved by using small size toner. However, small size toner often causes mottles in multiplex transfer full color images. This study investigated the cause of mottle in the multiplex transfer process. The top toner layer in the multiplex transfer process was observed in detail, and size distributions of toner particles were measured before and after the transfer process. It was found that small size toner was apt to have partial lacks of toner particles in the top toner layer of multiplex transfer. The small size toner was difficult to transfer, especially when using a weak transfer electric field. Furthermore, the mottle was found to be caused because the particle size dependency of the force due to transfer electric field was stronger than that of van der Walls force.
