| 摘要 |
PROBLEM TO BE SOLVED: To obtain a proper image, when an AC voltage is used, as the development bias voltage, in a development device in a high-speed printer or a copying machine, in which the printing speed exceeds 60 pages per minute. SOLUTION: In an electrophotographic apparatus, using two-component developer which is the mixture of toner and a carrier, using a development device including a development roll having a magnetic pole inside, having a development bias power source for superimposing a DC voltage on the AC voltage, as the development bias voltage, to be applied to the development roll, and forming an image by developing the toner on a photoreceptor, the volume ratio of the carrier in the space nipped between the development roll and the photoreceptor is in the range of 32-46%. Further, the resistivity of the carrier when an electric field of 2,000 V/cm is applied thereto is equal to or more than 3×10<SP>10</SP>Ωcm. COPYRIGHT: (C)2004,JPO&NCIPI |
