Behavior of Charge Control Agent (CCA) in Two-Component Developer

Abstract

The relationship between the charge control capabilities of CCA and its modes of existance in two-component developer was investigated. Trianilino-triphenyl-methane TATPM was used as a positive type CCA. The highest charge up speed and the largest amount of charge were observed on the CCA-free toner particles which were in contact with the carrier particle surface on which the fine TATPM particles were deposited. The amount of positive charge on the CCA-free toner particles caused by the externally added TATPM particles in a toner-carrier mixture was larger than that on the conventional pulverized toner particles in which almost all TATPM particles are in its inner part. The results show that, during the toner-carrier mixing process, fine TATPM particles were produced and deposited onto the carrier particle surface. Then, the TATPM particles moved to the toner particle surface. As a result, the contact charge generated between the fine TATPM particles and the carrier particle surface took the main part of the positive charge on the CCA-free toner particles. The amount of TATPM deposited on the carrier surface was determined by the absorption at 602 nm of the TATPM / ethanol solution extracted from the carrier/ethanol dispersion. The relationship between the amount of TATPM on carrier surface and amount of positive charge on the toner was discussed.