Influence of Charge Control Agent and Development Roller Surface on Toner Charging

Abstract

The effects of charge control agents (CCAs), especially for monocomponent nonmagnetic toner, were assessed in terms of their surface energies. The solid surface energy was calculated by the extended Fowkes equation. The energy value varied with CCA species and their content. The increase in surface energy created by adding excess CCA was one of the reasons for an observed increase in background density of print image. From infrared spectroscopy and viscosity measurements, it became apparent certain types of positive CCAs interact with polyester toner resin. It was also clarified that the material of the development roller could influence toner charge and print image quality. High-quality image prints were obtained by using a suitable combination of a chargeable toner and suitable roller material as tribocharge donor. To obtain high-quality image prints by monocomponent nonmagnetic development with positive toner, it is important to select a polyester resin and and a CCA that keep toner surface energy low and a suitable combination of toner having high chargeability and development roller material suitable as tribocharge donor.