Magnetic carrier and two-component developer

Patent metadata

Field	Value
Publication number	US-9811019-B2
Application number	US-201214129493-A
Country	US
Kind code	B2
Filing date	Jun 21, 2012
Priority date	Jun 29, 2011
Publication date	Nov 7, 2017
Grant date	Nov 7, 2017

Abstract

A magnetic carrier is provided which can suppress a decrease in glossiness even in a long term use for POD which requires high glossiness. A magnetic carrier includes a filled core particle in which a silicone resin is filled in pores of a porous magnetic core particle and a vinyl resin coating a surface of the filled core particle. In a pore distribution of the porous magnetic core particle measured by a mercury intrusion method, a cumulative pore volume in a pore diameter range of 0.1 to 3.0 μm is 35.0 to 95.0 mm 3 /g, and in a pore distribution of the filled core particle measured by a mercury intrusion method, a cumulative pore volume in a pore diameter range of 0.1 to 3.0 μm is 3.0 to 15.0 mm 3 /g. The magnetic carrier includes 1.2 to 3.0 parts by mass of the vinyl resin to 100.0 parts by mass of the filled core particle.

First claim

The invention claimed is:

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 mm 3 /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 mm 3 /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.

2. A two-component developer comprising:
a magnetic carrier; and
a toner,
wherein the toner includes an inorganic fine powder and toner particles containing a binder resin, a coloring agent, and a wax, and
the magnetic carrier is the magnetic carrier according to claim 1 .

Assignees

• Kamae Kentaro
• Komatsu Nozomu
• Ishigami Koh
• Baba Yoshinobu
• Canon Kk

Inventors

• Kamae Kentaro
• Komatsu Nozomu
• Ishigami Koh
• Baba Yoshinobu

Classifications

• G03G9/1075

  Structural characteristics of the carrier particles, e.g. shape or crystallographic structure · CPC title

• G03G9/1133 Primary

  obtained by reactions only involving carbon-to-carbon unsaturated bonds · CPC title

• G03G9/1131

  Coating methods; Structure of coatings · CPC title

• G03G9/1136

  containing silicon atoms · CPC title

• G03G9/107

  having magnetic components · CPC title