MAGNETIC CARRIER AND TWO-COMPONENT DEVELOPER

• US 20120214097A1
• Filed: 08/24/2011
• Published: 08/23/2012
• Est. Priority Date: 09/06/2010
• Status: Abandoned Application

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Baba, Yoshinobu, Ishigami, Koh, Naka, Takeshi
• Application Number:
  US13/217,216
• Publication Number:
  US 20120214097A1
• Time in Patent Office: Days
• US Class Current: 430/111.32
• CPC Class Codes: G03G 9/1075 Structural characteristics of the carrier particles, e.g. shape or crystallographic structure
• CPC Class Codes: G03G 9/108 Ferrite carrier, e.g. magnetite
• CPC Class Codes: G03G 9/113 having coatings applied thereto
• CPC Class Codes: G03G 9/1135 obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: G03G 9/1138 Non-macromolecular organic components of coatings

Abstract

Provided are a magnetic carrier and a two-component developer comprising the magnetic carrier. The magnetic carrier comprises magnetic carrier particles, each of which comprises a magnetic carrier core, the surface of which is coated with a charge control agent and further coated with a resin coat layer containing a resin composition.

Claims

1. A magnetic carrier comprising magnetic carrier particles, each of which comprises a magnetic carrier core, a charge control agent and a resin composition, wherein

the surface of the magnetic carrier core is coated with the charge control agent, and wherein a resin coat layer containing the resin composition is present on the surface of a coat of the charge control agent.

2. The magnetic carrier according to claim 1, wherein the surface of the magnetic carrier core is coated with the charge control agent in a coverage rate of 70 area % or more.

3. The magnetic carrier according to claim 1, wherein the charge control agent contains a quaternary ammonium salt.

4. The magnetic carrier according to claim 1, wherein the resin composition contains a tetrahydrofuran (THF)-soluble matter having a weight average molecular weight (Mw) of from 100,000 or more to 1,000,000 or less.

5. The magnetic carrier according to claim 1, wherein the magnetic carrier core contains a ferrite component and a SiO₂ component.

6. The magnetic carrier according to claim 1, wherein the magnetic carrier is obtained by dry-process coating the magnetic carrier core with the charge control agent, and further dry-process coating the thus coated magnetic carrier core with the resin composition.

7. The magnetic carrier according to claim 6, wherein the dry-process coating is performed by using a dry-process coating apparatus, the dry-process coating apparatus having a cylindrical rotatory member having a plurality of stirring members and a driving section configured to rotate the rotatory member;

the plurality of stirring members being arranged in rows in the direction along the rotation shaft of the rotatory member; and

the rotatory member being rotated to perform the coating.

8. A two-component developer comprising a toner and a magnetic carrier, wherein the magnetic carrier is the magnetic carrier according to claim 1.

9. A process for producing a magnetic carrier comprising the steps of:

dry-process coating a magnetic carrier core with a charge control agent; and

further dry-process coating the thus coated magnetic carrier core with a resin composition.

10. The process for producing the magnetic carrier according to claim 9,

wherein the dry-process coating is performed by using a dry-process coating apparatus, the dry-process coating apparatus having a cylindrical rotatory member having a plurality of stirring members and a driving section configured to rotate the rotatory member;

the plurality of stirring members being arranged in rows in the direction along the rotation shaft of the rotatory member; and

the rotatory member being rotated to perform the coating.