DEVELOPER FOR REPLENISHMENT

摘要

PROBLEM TO BE SOLVED: To provide a developer for replenishment by which stable images can be obtained throughout the life of a main body. SOLUTION: The developer for replenishment in which a carrier of the developer for replenishment for use in a developing method of performing development while replenishing the developer for replenishment is formed as a magnetic material dispersion type resin carrier dispersed with metal compound particles in a binder resin; said magnetic material dispersion type resin carrier has the amount TH20- H (mass%) of moisture absorption after resting in the environment of 30 deg.C and 80% RH, the amount TH20- L (mass%) of moisture adsorption after resting in the environment of 23 deg.C and 5% RH and surface area Sm (cm<2> /g) satisfying the following equations 1 and 2; 5.50×10<-6> <=TH20- H /(100×Sm)<=1.50×10<-5> (1) 9.00×10<-7> <=TH20- L/(100×Sm)<=5.50×10<-6> (2); the toner of the developer for replenishment is formed to a weight average grain size 3 to 10μm and is formulated at a ratio of 2 to 50 parts by mass the toner per part by mass of the magnetic material dispersion type resin carrier; and the two-component system developers existing in a developing device are formulated at a ratio of 0.05 to 0.20 parts by mass the toner per part by mass of the magnetic material dispersion type resin carrier, is provided.