TREA

Ferrite carrier for electrophotographic developer, method for producing the same, and electrophotographic developer

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Information

  • Patent Application
  • 20070231731
  • Publication Number
    20070231731
  • Date Filed
    March 30, 2007
    19 years ago
  • Date Published
    October 04, 2007
    18 years ago
Information
Abstract
A ferrite carrier for an electrophotographic developer having a compression breaking strength of 150 MPa or more, a rate of compressive change of 15.0% or more and a shape factor SF-1 of 100 to 125, a method for producing the same, and an electrophotographic developer containing the ferrite carrier.
Description
Claims
  • 1. A ferrite carrier for an electrophotographic developer having a compression breaking strength of 150 MPa or more, a rate of compressive change of 15.0% or more and a shape factor SF-1 of 100 to 125.
  • 2. The ferrite carrier for an electrophotographic developer according to claim 1, wherein the carrier has a composition represented by the following general formula: (MnO)x(MgO)y(Fe2O3)z
  • 3. The ferrite carrier for an electrophotographic developer according to claim 1, wherein the ferrite carrier has an average particle size (D50) of 25 to 45 μm.
  • 4. The ferrite carrier for an electrophotographic developer according to claim 1, wherein the ferrite carrier is surface-coated with a resin.
  • 5. A method for producing a ferrite carrier for an electrophotographic developer, comprising the steps of: grinding, mixing and pelletizing ferrite raw materials;calcining the pellets at 900 to 1200° C.;grinding the preliminarily fired pellets;producing a slurry from the resulting particles;setting slurry particle sizes, D50 and D90, at 3.0 μm or less and 4.5 μm or less, respectively; andsintering at 1150 to 1230° C. for 1 to 24 hours.
  • 6. The method for producing the ferrite carrier for an electrophotographic developer according to claim 5, wherein the slurry particle sizes D50 and D90, are 1.0 to 2.0 μm and 1.5 to 3.0 μm, respectively.
  • 7. The method for producing the ferrite carrier for an electrophotographic developer according to claim 5, wherein a difference in temperature between the sintering and the calcining is 250° C. or less.
  • 8. The method for producing the ferrite carrier for an electrophotographic developer according to claim 5, further comprising the step of surface coating with a resin after the sintering.
  • 9. An electrophotographic developer comprising the ferrite carrier according to claim 1 and a toner.
Priority Claims (1)
Number Date Country Kind
JP2006-093677 Mar 2006 JP national