| 摘要 |
PURPOSE:To stabilize the triboelectrostatic chargeability of colored particles and to prevent the decrease of image densities and fogging by incorporating composite fine particles formed by sticking inorg. fine particles to the surface of resin fine particles, inorg. oxide particles and hydrophobic silica fine particles into the above developer. CONSTITUTION:This developer is constituted by using the colored particles consisting of at least a resin and coloring agents, the composite fine particles formed by sticking the inorg. fine particles to the surface of the resin fine particles, the inorg. oxide fine particles and the hydrophobic silica fine particles. The resin fine particles having 0.1 to 7mum average grain size are preferable in terms of cleanability and triboelectrostatic chargeability. The inorg. fine particles likewise having 5 to 200nm average grain size are preferable as the inorg. fine particles. The inorg. fine particles are exemplified by alumina, titania, zirconia, etc., and the oxide particles of group IV-A are particularly adequate. Further, the hydrophobic silica fine particles are formed by treating the hydrophilic groups, such as hydroxyl groups, existing on the surfaces of the silica fine particles themselves with a hydrophobic substituent to impart a hydrophobic property thereto. |
