Magnetic carrier and two-component developer
AssigneeCanon Kabushiki Kaisha
InventorsYoshinobu Baba, Ryoichi Fujita, Takaaki Kaya, Kazuo Terauchi
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Abstract
A magnetic carrier includes a magnetic material-dispersed resin core containing at least a magnetic material and a binder resin. The surface of the magnetic material-dispersed resin core is coated with a coating material containing at least a fluorine resin and 1 to 40 parts by weight of fine particles based on 100 parts by weight of the fluorine resin. The coating material is in an amount of 0.3 to 4.0 parts by weight based on 100 parts by weight of the magnetic material-dispersed resin core. The magnetic carrier has a contact angle of 95 to 125°. A two-component developer is also provided which makes use of the magnetic carrier.
Claims13
A magnetic carrier comprising carrier particles, wherein
- each carrier particle comprises a carrier core and a coating material for coating the carrier core,
- the carrier core comprises a binder resin and magnetic particles dispersed in the binder resin,
- the coating material comprises at least 100 parts by weight of a fluorine resin and 1 to 40 parts by weight of fine particles, said fluorine resin being a graft copolymer constituted of a unit represented by the formula (A)
- wherein a, b, c, and d each independently represent an integer of 1 or more:
- and m and n each independently represent an integer of 1 to 10,
- the carrier comprises at least 100 parts by weight of the carrier core and 0.3 to 4.0 parts by weight of the coating material, and
- a contact angle of the magnetic carrier is 95 to 125°.
A two-component developer, comprising a toner and a magnetic carrier, wherein
- the toner comprises at least toner particles and an external additive,
- the toner particles contain at least a binder resin, a release agent, and a colorant, and an agglomeration of the toner is 20 to 90,
- the magnetic carrier comprises carrier particles,
- each carrier particle comprises a carrier core and a coating material for coating the carrier core,
- the carrier core comprises a binder resin and magnetic particles dispersed in the binder resin,
- the coating material comprises at least 100 parts by weight of a fluorine resin and 1 to 40 parts by weight of fine particles, said fluorine resin being a graft copolymer constituted of a unit represented by the formula (A)
- wherein a, b, c, and d each independently represent an integer of 1 or more;
- and m and n each independently represent an integer of 1 to 10,
- the carrier comprises at least 100 parts by weight of the carrier core and 0.3 to 4.0 parts by weight of the coating material, and
- a contact angle of the magnetic carrier is 95 to 125°.
Dependencies are inferred from the claim text.