Patent ID: 7561831

Claim:
An image forming apparatus, comprising: development means for developing an electrostatic latent image formed on a photoconductor, using developer including toner and carrier, the development means including a developer tank for storing developer, developer conveying means for pumping the developer up from the developer tank and conveying the developer to a surface facing the photoconductor, and a developer discharge outlet provided on a bottom surface of the developer tank; discharge means for discharging developer from the development means, the discharge means having opening and closing means for opening and closing the developer discharge outlet, the developer being discharged from the developer tank via the developer discharge outlet by closing the developer tank via the developer discharge outlet by closing the developer discharge outlet with use of the opening and closing means at a time of image forming so that the developer does not leak from the developer tank via the developer discharge outlet, and by opening the developer discharge outlet with operation of the opening and closing means at a time of developer discharge; charging control means for controlling a photoconductor potential that is a surface potential of a face of the photoconductor, which face is opposite to the development means; development bias control means for controlling a development bias potential that is a surface potential of a face of the development means, which face is opposite to the photoconductor; and main control means for controlling the charging control means and the development bias control means so that a potential difference between the photoconductor potential and the development bias potential during developer discharge from the development means and after a predetermined period of time has elapsed since the start of developer discharge is smaller than the potential difference in image forming.