Patent ID: 8032043
Filing Date: 2011-10-04
Classification: G03G

Abstract:
1. An image forming apparatus of non-contact developing type, the apparatus comprising: an image carrier; a developing roller for giving non-magnetic mono-component toner to the image carrier; a supply roller for supplying the toner to the developing roller; a buffer for storing and agitating the toner to be supplied to the supply roller; a hopper for storing the toner to be replenished into the buffer; and a voltage application section for applying a developing bias between the image carrier and the developing roller, wherein the voltage application section applies, as the bias voltage, the developing voltage Vmin is set to a first value when an accumulated replenishment rate determination value SRin is a positive value, the accumulated replenishment rate determination value SRin being obtained by the following expression: where the first value being a value at which an electric field intensity in an image area of an electrostatic latent image on the image carrier is sufficient to cause the toner to fly from the developing roller to the image carrier and an electric field intensity in a background area of the electrostatic latent image on the image carrier is insufficient to cause the toner to fly from the developing roller to the image carrier, and the developing voltage Vmin is set to a second value when the accumulated replenishment rate determination value SRin is a negative value, the second value being a value at which the electric field intensity in the image area of the electrostatic latent image on the image carrier and the electric field intensity in the background area of the electrostatic latent image on the image carrier are both sufficient to cause the toner to fly from the developing roller to the image carrier.