Kyocera Mita Corporation

Tadao Sumiyoshi

Tomohide Iida

A two-component-type developing agent comprising a silicone resin-coated carrier and a positively charging toner, the silicone coated carrier having an average particle diameter of from 60 to 110 .mu.m, the silicone resin coating having an average thickness of from 0.1 to 0.3 .mu.m, the carrier having a resistivity of from 1.5.times.10.sup.8 to 1.5.times.10.sup.11 .OMEGA..multidot.cm, the toner concentration being from 3.0 to 5.0 % by weight and the amount of electric charge by friction of the toner based on the suction method being from +10 to +20 .mu.c/g. The silicone resin-coated carrier and the developing agent feature long life without permitting the spent toner to adhere on the carrier surfaces, without permitting the carrier coating to peel off even after repetitively used for extended periods of time, featuring stable amount of electric charge by friction, stable developing properties, and maintaining favorable image quality for extended periods of time developing none of carrier dragging, toner scattering in the machine, background fogging or defective image density.

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Matsubara, Japan

Tadao Sumiyoshi