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. 18, 2014
Filed:
Jun. 15, 2010
Kaori Kinoshita, Hiroshima-ken, JP;
Shinji Uemoto, Hiroshima-ken, JP;
Eiichi Kurita, Hiroshima-ken, JP;
Kaori Kinoshita, Hiroshima-ken, JP;
Shinji Uemoto, Hiroshima-ken, JP;
Eiichi Kurita, Hiroshima-ken, JP;
Toda Kogyo Corporation, Hiroshima-ken, JP;
Abstract
The present invention relates to a magnetic carrier for an electrophotographic developer comprising spherical composite particles comprising spherical composite core particles comprising at least ferromagnetic iron oxide fine particles and a cured phenol resin and having an average particle diameter of 1 to 100 μm, and a melamine resin coating layer formed on the respective core particles, wherein a ratio of Rto R(R/R) in which Ris an electric resistance value as measured when applying a voltage of 100 V to the magnetic carrier; and Ris an electric resistance value as measured when applying a voltage of 300 V to the magnetic carrier, is controlled to lie within the range of 1 to 50. The magnetic carrier according to the present invention is capable of maintaining an adequate electric resistance value upon development, providing images having an excellent image quality, exhibiting a good durability, obtaining a good reproducibility of uniform solid image portions having a high image density, and keeping high quality images having an excellent gradation for a long period of time.