TWO-COMPONENT TYPE DEVELOPER AND DEVELOPING DEVICE

PROBLEM TO BE SOLVED: To provide a two component type developer which makes rapid electrostatic chargeability of toner obtainable and can suppress the deterioration in electrostatic chargeability for a long period of time even when applied to a simple developing method not using a toner concentration detecting means and which can achieve good image stability even under a high temperature and humidity and low temperature and humidity. SOLUTION: The two component type developer is used for the developing apparatus which conveys a developer containing a magnetic toner and a magnetic carrier existing within a developer housing section while regulating the amount of conveyance toward a developing region by a developer regulating member existing on the downstream side in the developer conveyance direction of the developer housing section while rotating a developing sleeve internally having a magnetic field generating housing and captures the toner into the developer housing section into the developer housing section according to the volume of the dveloper in the developer housing section. The above magnetic toner has at least a binder resin, a release agent and magnetic powder, wherein the weight average particle size is 3 to 20 μm, the ratio of the weight average particle size/the number average grain size is ≤1.40 and the average circularity is ≥0.970, and the liberation rate of of iron and iron compound is 0.05 to 3.00%. COPYRIGHT: (C)2005,JPO&NCIPI