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:
Oct. 18, 2011
Filed:
Apr. 17, 2007
Kimitoshi Yamaguchi, Numazu, JP;
Naoki Imahashi, Mishima, JP;
Masashi Nagayama, Mishima, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
The present invention can provide small-diameter core material particles for electro photographic carrier, the particles that can prevent occurrences of carrier adhesions and reduce toner spent, have excellent durability and cause little fluctuations in image density with a narrow particle diameter distribution, and an efficient, cost-effective production method thereof. That is, the core material particles for electro photographic carrier are particles wherein the weight average particle diameter, Dw, is in the range of 22 μm to 32 μm, the ratio of Dw to the number average particle diameter, Dp, satisfies the condition, 1<Dw/Dp<1.20, the content of particles smaller than 20 μm in diameter is in the range of 0% by mass to 7% by mass and smaller than 36 μm is in the range of 90% by mass to 100% by mass, and the BET specific surface area is in the range of 300 cm/g to 900 cm/g.