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:
Mar. 10, 2009
Filed:
Aug. 26, 2005
Hiroyuki Mabuchi, Hitachinaka, JP;
Masayoshi Nakayama, Hitachinaka, JP;
Hirobumi Ooyoshi, Hitachinaka, JP;
Hiroyuki Mabuchi, Hitachinaka, JP;
Masayoshi Nakayama, Hitachinaka, JP;
Hirobumi Ooyoshi, Hitachinaka, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
A developing device is provided with a developer accommodating vessel accommodating developer having as primary components a nonmagnetic toner and magnetic particles referred to as a carrier. The carrier is composed of a magnetic material as a core material that is uniformly covered with an insulating synthetic resin. The toner is mixed with the carrier at a weight ratio to the overall weight of the developer of 3-10%. The carrier has an average particle size of 65 μm or less and a saturation magnetization of at least 70 emu/g. The developing device includes a developing roller and a sleeve roller that rotates about the developing roller. The surface of the sleeve roller is processed with metal shot to achieve a surface roughness of 0.45-1.08 times the average particle size of the carrier, or more specifically a roughness Rz of about 30 μm.