The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 16, 2010
Filed:
Mar. 11, 2009
Koichi Sakata, Numazu, JP;
Tomio Kondou, Numazu, JP;
Shinichiro Yagi, Numazu, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
Provided is a developing device containing a two-component developer including a magnetic carrier and a toner; a developer bearing member containing a nonmagnetic developing sleeve configured to bear the two-component developer on a surface thereof while rotating; a magnetic field generating unit fixed inside of the nonmagnetic developing sleeve; and a developer amount control member configured to control an amount of the two-component developer borne on the developer bearing member. The magnetic carrier contains a core material and a coating layer coated on the core material, and the coating layer containing a binder resin and conductive particles. The magnetic carrier satisfy a ratio D/h of 1.00<[D/h]≦1.95, where D denotes an average primary particle diameter of the conductive fine particles, and h denotes a thickness of the coating layer, and a ratio Ra/D of 1.0<[Ra/D]<10.0, where Ra denotes a surface roughness of the developing sleeve.