Carrier core material and electrophotographic carrier using same and electrophotographic developer
AssigneesDowa Electronics Materials Co., Ltd., Dowa IP Creation Co., Ltd.
InventorShou Ogawa
Life of this patent
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Abstract
A carrier core material is represented by a composition formula MXFe3-XO4 (where M is at least one type of metal element selected from Mg, Mn, Ca, Ti, Cu, Zn and Ni, 0<X<1), in which part of M and/or Fe is substituted with Sr and formed of ferrite particles, and in the carrier core material, a Sr content is equal to or more than 2500 ppm but equal to or less than 12000 ppm, the amount of Sr eluted with pure water at a temperature of 25° C. is equal to or less than 50 ppm, an apparent density is equal to or more than 1.85 g/cm3 but equal to or less than 2.25 g/cm3 and magnetization σ1k when a magnetic field of 79.58×103 A/m (1000 oersteds) is applied is equal to or more than 63 Am2/kg but equal to or less than 75 Am2/kg.
Claims5
A carrier core material which is represented by a composition formula MXFe3-XO4, wherein M is Mn and 0<X<1, in which part of M and/or Fe is substituted with Sr and which is formed of ferrite particles,
- wherein a Sr content is equal to or more than 2500 ppm but equal to or less than 12000 ppm,
- an amount of Sr eluted with pure water at a temperature of 25° C. is equal to or less than 50 ppm,
- an apparent density is equal to or more than 1.85 g/cm3 but equal to or less than 2.25 g/cm3 and
- magnetization σ1k when a magnetic field of 79.58×103 A/m (1000 oersteds) is applied is equal to or more than 63 Am2/kg but equal to or less than 75 Am2/kg.
Dependencies are inferred from the claim text.