Carrier core material for electrophotographic developer and method for producing the same, and carrier for electrophotographic developer and developer containing said carrier core material
AssigneePowdertech Co., Ltd.
InventorsHiroki Sawamoto, Atsushi Nil, Yuji Ito, Hajime Akiba, Shinya Hanyu
Life of this patent
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Abstract
The present invention relates to a carrier core material for electrophotographic developer, having a ferrite composition and having a supernatant transmittance of 85.0% or more, a method for producing the carrier core material, a carrier for electrophotographic developer, containing the carrier core material, and a developer containing the carrier.
Claims21
A carrier core material for an electrophotographic developer, comprising a ferrite composition having a transition metal oxide as a main component, wherein an amount of an ultrafine powder contaminant adhering to a surface of the carrier core material is attenuated by determining the transmittance with a spectrophotometer of a supernatant separated from the ultrafine powder.
A method for attenuating toner color contamination, comprising:
- separating a ferrite ultrafine powder contaminant adhering to a sintered ferrite carrier core product by means of a supernatant;
- and
- determining the transmittance of the supernatant with a spectrophotometer.
Dependencies are inferred from the claim text.