Patent ID: 7574164

Claim:
An electrophotographic apparatus comprising: a photoconductor; and two developing rollers facing the photoconductor, wherein a developer fed out from between the two developing rollers is supplied to the photoconductor by the two developing rollers to form a toner image on the photoconductor, wherein the developer includes a carrier having a volume-average particle size less than 70 μm and a volume resistivity of at least 10 6 Ω·cm, wherein a volume ratio of the carrier in a facing portion between the photoconductor and the developing rollers is in a range of 30% to 46%, wherein the carrier has a volume resistivity of at least 10 12 Ωcm when an intensity of an applied electric field is 1000 V/cm and a volume resistivity of equal to or less than 10 10 Ωcm when the intensity of the applied electric field is 10000 V/cm.