Magnetic carrier, two-component developer, replenishing developer, and image forming method

摘要

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.

主权项

1. 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.