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US 5,962,175 AGranted
Binder-type carrier and method of manufacturing same
AssigneeMinolta Co., Ltd.
InventorsYoshiaki Tanaka, Hideaki Yasunaga, Tomoharu Nishikawa
Life of this patent
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Abstract
A binder-type carrier which does not cause image defects or uneven density and has excellent production characteristics, and a binder-type carrier manufactured by said method. The binder-type carrier has a magnetic powder content of 75-90 wt % and is produced by pulverizing via a mechanical pulverizer a material which has been kneaded within a predetermined temperature range using an extrusion kneader provided with two or more kneading units.
Claims20
A carrier comprising:
- a binder resin;
- and
- magnetic powder dispersed in said binder resin;
- wherein the magnetic powder content a1 and the amount b of magnetic powder exposed on the carrier particle surface satisfies Equation (I)
- b=0.4(a1-80)+k1
- wherein a1 is about 75 to about 90 (wt %), and k1 is about 4 to about 13 (wt %), the carrier shape coefficient is about 0.8 to about 0.95, and the ratio Dv/Dp of the volume-average particle size Dv and the number-average particle size Dp is less than about 1.30.
3 more elements
Dependencies are inferred from the claim text.