INFLUENCE OF CHARGE CONTROL AGENT AND DEVELOPMENT ROLLER SURFACE ON TONER CHARGING

The effects of charge control agents (CCAs), especially for monocompon ent nonmagnetic toner, were assessed in terms of their surface energie s. The solid surface energy was calculated by the extended Fowkes equa tion. 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 app arent certain types of positive CCAs interact with polyester toner res in. It was also clarified that the material of the development roller could influence toner charge and print image quality. High-quality ima ge prints were obtained by using a suitable combination of a chargeabl e toner and suitable roller material as tribocharge donor. To obtain h igh-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 suitab le as tribocharge donor.