| CPC G03G 9/09328 (2013.01) [G03G 9/0823 (2013.01); G03G 9/09378 (2013.01); G03G 15/0812 (2013.01)] | 8 Claims |
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1. A developing apparatus, comprising:
a toner comprising a toner particle having a metal compound particle on a surface of the toner particle;
a toner bearing member configured to bear the toner, the toner bearing member having a two-layer configuration comprising a conductive elastic layer and a surface layer; and
a toner regulating member contacting the toner bearing member and being configured to regulate the toner borne on the toner bearing member, wherein
a volume resistivity of the toner as determined by impedance measurement is 1.0×1010 to 1.0×1014 Ω·cm,
the toner bearing member exhibits an elementary process of an RC parallel circuit model attributable to the conductive elastic layer and an elementary process of an RC parallel circuit model attributable to the surface layer in the impedance measurement,
a volume resistance value Rdr per unit area of the toner bearing member is from 5.0×105 to 2.0×108 Ω/cm2,
a capacitance Cdr per unit area of the toner bearing member is from 300 to 900 pF/cm2, and
1.5≤(Cdr/Ctn)≤4.5 and 1.0×10−4≤(Rdr/Rtn)≤1.0
where Ctn (pF/cm2) is a capacitance per unit area of the toner and Rtn (Ω/cm2) is a volume resistance value per unit area of the toner as converted by a parallel plate capacitor model at a thickness of 1.5 times a weight-average particle diameter D4 of the toner as obtained by an electrical detection band method based on the volume resistivity and capacitance obtained by the impedance measurement.
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