DEVELOPER FOR REPLENISHMENT, AND DEVELOPING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a developer for replenishment, which is efficiently mixed with a developer in a developing device and achieves high durability and high image quality, and which is for use in a two-component developing method by which development is performed while replenishing the developer for replenishment including at least toner and a magnetic carrier to a developing device, and in which excess carrier in at least the developing device is discharged from the developing device, and to provide a developing method. SOLUTION: In the developer for replenishment, the toner is blended in a ratio of 2-50 parts by mass to 1 part by mass of a magnetic carrier. The toner is obtained by an emulsion aggregation method including a step of forming fine particle aggregates comprising at least fine polymer particles and fine colorant particles and an aging step of causing fusion between fine particles in the fine particle aggregates, the toner has D4 of 3.0-11.0μm, and particles having a circle-equivalent diameter of 0.6-2.0μm occupy≤30% by number. The magnetic carrier has D50 of 15-70μm, a true specific gravity of 2.5-4.2 g/cm3and intensity of magnetization of 40-70 Am2/kg. COPYRIGHT: (C)2007,JPO&INPIT