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.

Date of Patent:
Aug. 24, 2004

Filed:

Nov. 17, 2003
Applicant:
Inventors:

Tsukuru Kai, Kanagawa, JP;

Hisashi Shoji, Kanagawa, JP;

Assignee:

Ricoh Company, Ltd., Tokyo, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G03G 1/501 ;
U.S. Cl.
CPC ...
G03G 1/501 ;
Abstract

In a developing device including a plurality of developing sections each including a developer carrier that causes a developer deposited thereon to form a magnet brush and contact an image carrier, the developer carrier including: a rotatable nonmagnetic sleeve; and a stationary magnet roller accommodated in the sleeve and including a magnetic pole for scooping up the developer to the sleeve, a magnetic pole for conveying the developer deposited on the sleeve, and a main magnetic pole for causing the developer to rise on the sleeve in a form of the magnet brush. The plurality of developing sections include at least one developing section in which a flux density of the main magnetic pole in a normal direction has an attenuation ratio of 40% or above and at least one developing section in which said flux density has an attenuation ratio of 30% or below.


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