| 摘要 |
PURPOSE:To form a clear image with high density generating no fog even if a carrier of a small diameter is used, by specifying a bulk density of a developer consisting of a toner whose shape is all spherical and a carrier of a specified particle diameter. CONSTITUTION:A toner and a carrier are both formed by spherical particle powders, therefore, even if the particle is small in its diameter, a fall of the fluidity is small, and by a small addition quantity of a fluidity improving agent, a necessary fluidity can be obtained. Also, with regard to a developer D, when its still bulk density is set to >=0.6mg/ml, and its hardening bulk density is set to >=0.8 mg/ml, the fluidty becomes enough and the toner and the carrier are electrified by a sufficient charge quantity by a friction, and an adhesive property to a latent image of the toner particle becomes good. Also, when a mean particle diameter of the carrier particle is set to a size of 10-50mum of the almost same extent as that of the toner particle, its surface area increases remarkably comparing with the carrier of a large diameter of the same quantity, a frictional electrifying function of the carrier becomes a relatively large state, an allowable width of a toner density becomes large remarkably, and a replenishment of the toner is executed easily. |
