Patent ID: 7031646

Claim:
A developing device, comprising: an image carrier, on which an electrostatic latent image is formed; a first roller, opposed to the image carrier with a gap in between; a second roller, being in contact with the first roller such that toner of a one-component type is supplied onto the image carrier by way of the first roller to develop the electrostatic latent image as a visible toner image; a single power source, which supplies a bias voltage in which an AC voltage is superposed on a DC bias voltage, the bias voltage being supplied to the first roller through a first path and to the second roller through a second path; and a resistor, provided on the first path between the first roller and a branching point of the first path and the second path, wherein the resistor has such a value that a potential difference between the first roller and the second roller converges on a reference value within a time period during which a potential difference between the first roller and the image carrier is such a value that charged toner is supplied from the first roller to the image carrier.