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:
Feb. 15, 2000
Filed:
Nov. 05, 1997
Yasushige Nakamura, Kawasaki, JP;
Norio Sawatari, Kawasaki, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
Toner magnetic powder which uses a resin as a binder and contains a dye is coated by a methyl methacrylate resin, thereby forming a carrier. A developer is formed by such a carrier in which those two components are mixed. An electric conductivity of the impurity extracted water of the carrier due to the pressurization in the pure water is set to 60 .mu.S/cm or less. Namely, the purity is improved so that the electric conductivity of the impurity extracted water of the methyl methacrylate resin due to the pressurization in the pure water is set to 20 .mu.S/cm or less, and the purity is improved so that the electric conductivity of the impurity extracted water of the magnetic powder due to the pressurization in the pure water is set to 60 .mu.S/cm or less, thereby forming a carrier. A carbon addition amount upon manufacturing of the carrier is controlled so that the electric resistance of the carrier is set to a value within a range of 1.times.10.sup.4 to 1.times.10.sup.8 .OMEGA.cm. Further, a carbon addition amount upon manufacturing of the toner is limited so that the electric resisance of the toner is set to 1.times.10.sup.11 .OMEGA.cm or more.