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:
Apr. 10, 2007
Filed:
Nov. 30, 2004
Mieko Kakegawa, Kanagawa, JP;
Sumio Kamoi, Tokyo, JP;
Kyohta Koetsuka, Kanagawa, JP;
Noriyuki Kamiya, Kanagawa, JP;
Tsuyoshi Imamura, Kanagawa, JP;
Mieko Kakegawa, Kanagawa, JP;
Sumio Kamoi, Tokyo, JP;
Kyohta Koetsuka, Kanagawa, JP;
Noriyuki Kamiya, Kanagawa, JP;
Tsuyoshi Imamura, Kanagawa, JP;
Ricoh Company, Ltd, Tokyo, JP;
Abstract
A developing roller includes a developing sleeve having a nonmagnetic material, and a magnet roll provided inside the developing sleeve and formed by dispersing a magnetic powder in a polymer compound. A portion of the magnet roll corresponding to a developing pole of the magnet roll is equipped with a main-pole molded magnet whose magnetic force per unit of volume is greater than that of the magnet roll. A magnetic pole adjacent to the developing pole of the magnet roll downstream in the developer conveyance direction has a peak magnetic flux density on the developing sleeve greater than that of the developing pole, and has a half value width, which is the width of the magnetic pole at which a magnetic flux density of one-half the peak magnetic flux density is exhibited, greater than that of the developing pole.