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Magnetic carrier and two-component developer

  • US 9,058,924 B2
  • Filed: 05/24/2013
  • Issued: 06/16/2015
  • Est. Priority Date: 05/28/2012
  • Status: Active Grant
First Claim
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1. A magnetic carrier comprising resin-containing ferrite particles each comprising a porous ferrite core having pores and a resin contained in the pores thereof,wherein:

  • in a pore diameter distribution of the pores measured by using a mercury intrusion method,a pore diameter at which a logarithmic differential pore volume shows the maximum value in the pore diameter range of from at least 0.10 μ

    m to not more than 3.00 μ

    m, is present within the pore diameter range of from at least 0.80 μ

    m to not more than 1.50 μ

    m,when P1 is a maximum value of a logarithmic differential pore volume in a pore diameter range of from at least 0.80 μ

    m to not more than 1.50 μ

    m, andP2 is a minimum value of a logarithmic differential pore volume in a pore diameter range of from at least 2.00 μ

    m to not more than 3.00 μ

    m,the porous ferrite core exhibits the P1 of from at least 0.07 mL/g to not more than 0.35 mL/g, and P2/P1 of from at least 0.05 to not more than 0.35the porous ferrite corei) has a resistivity at 100 V/cm of from at least 8.0×

    104 Ω

    ·

    cm to not more than 1.0×

    106 Ω

    ·

    cm,ii) contains an oxide of Mg of from at least 1.00 mass % to not more than 15.00 mass % as MgO with reference to a mass of the porous ferrite core, andiii) contains a metal oxide, the metal being at least one metal selected from the group consisting of Mn, Sr, and Ca, and a total content of the metal oxide as MnO, SrO and CaO is from at least 0.02 mass % to not more than 1.50 mass % with reference to a mass of the porous ferrite core.

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