US 9,811,019 B2
Magnetic carrier and two-component developer
Kentaro Kamae, Kashiwa (JP); Nozomu Komatsu, Toride (JP); Koh Ishigami, Abiko (JP); and Yoshinobu Baba, Yokohama (JP)
Assigned to Canon Kabushiki Kaisha, Tokyo (JP)
Appl. No. 14/129,493
Filed by Kentaro Kamae, Kashiwa (JP); Nozomu Komatsu, Toride (JP); Koh Ishigami, Abiko (JP); and Yoshinobu Baba, Yokohama (JP)
PCT Filed Jun. 21, 2012, PCT No. PCT/JP2012/066463
§ 371(c)(1), (2), (4) Date Mar. 31, 2014,
PCT Pub. No. WO2013/002296, PCT Pub. Date Jan. 3, 2013.
Claims priority of application No. 2011-144644 (JP), filed on Jun. 29, 2011.
Prior Publication US 2014/0220487 A1, Aug. 7, 2014
Int. Cl. G03G 9/10 (2006.01); G03G 9/113 (2006.01); G03G 9/107 (2006.01)
CPC G03G 9/1133 (2013.01) [G03G 9/1075 (2013.01); G03G 9/1131 (2013.01); G03G 9/1136 (2013.01)] 2 Claims
OG exemplary drawing
 
1. A magnetic carrier comprising:
a filled core particle including a porous magnetic core particle and a silicone resin filled in pores thereof; and
a vinyl resin coating a surface of the filled core particle,
wherein in a pore distribution of the porous magnetic core particle measured by a mercury intrusion method, a cumulative pore volume of the porous magnetic core particle is 35.0 to 95.0 mm3/g,
in a pore distribution of the filled core particle measured by a mercury intrusion method, a cumulative pore volume of the filled core particle is 3.0 to 15.0 mm3/g,
the content of the vinyl resin is 1.2 to 3.0 parts by mass with respect to 100.0 parts by mass of the filled core particle, and
the mercury intrusion method comprises the following steps:
weighing 1.0 g of the porous magnetic core particle or the filled core particle,
intruding a mercury into the pores of the porous magnetic core particle or the filled core particle while measuring a mercury intrusion pressure and a volume of the intruded mercury in a range of 13.8 kPa to 315.6 kPa and in a range of 316.3 kPa to 413.6 MPa,
obtaining the pore distribution of the porous magnetic core particle or the filled core particle, by calculation from the mercury intrusion pressure and the volume of the intruded mercury, and
computing the cumulative pore volume of the porous magnetic core particle or the filled core particle by integrating a Log differential pore volume in a pore diameter range of 0.1 to 3.0 μm in the pore distribution of the porous magnetic core particle or the filled core particle,
wherein the vinyl resin is a copolymer of
a vinyl monomer having a cyclic hydrocarbon group in its molecular structure, and
a methyl methacrylate macromonomer having a methacryloyl group at one terminal thereof.