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US 9,541,853 B2Granted
Magnetic carrier, two-component developer, replenishing developer, and image forming method
AssigneeCanon Kabushiki Kaisha
InventorsHironori Minagawa, Wakashi Iida, Nobuyoshi Sugahara, Minoru Yoshifuku, Yuto Onozaki
Life of this patent
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Abstract
A magnetic carrier includes resin-filled magnetic core particles including porous magnetic particles whose pores are filled with a resin, and resin coating layers on the surfaces of the resin-filled magnetic core particles. The porous magnetic particles have specific electrical properties.
Claims8
A magnetic carrier comprising:
- resin-filled magnetic core particles containing porous magnetic particles having pores therein and a resin present in the pores;
- and
- resin coating layers coating the surfaces of the resin-filled magnetic core particles, the resin coating layer including a coating resin, wherein:
- (i) the porous magnetic particles are made of Mn-Mg-Sr ferrite;
- (ii) the porous magnetic particles have a specific resistance in the range of 1.0×107 Ω·cm to 1.0×108 Ω·cm at an electric field intensity of 300 V/cm;
- and
- (iii) the porous magnetic particles have an electrical breakdown at electric field intensity in the range of 1,000 V/cm to 10,000 V/cm, and wherein:
- (iv) the magnetic carrier has a specific resistance in the range of 1.0×107 Ω·cm to 1.0×109 Ω·cm at an electric field intensity of 2,000 V/cm;
- (v) the magnetic carrier has a specific resistance in the range of 2.0×107 Ω·cm to 2.0×109 Ω·cm at an electric field intensity of 1,000 V/cm;
- (vi) the magnetic carrier has an electrical breakdown at electric field intensity in the range of 1,000 V/cm to 15,000 V/cm;
- (vii) the magnetic carrier exhibits a current in the range of 8.0 μA to 50.0 μA when a voltage of 500 V is applied thereto;
- and
- (viii) the resin content in the resin-filled magnetic core particles is in the range of 1.0 to 5.5 parts by mass relative to 100 parts by mass of the porous magnetic particles.
10 more elements
Dependencies are inferred from the claim text.