Controlling apparatus for developing roller, image forming device having the same, and developer controlling method thereof

摘要

A image forming apparatus having a developer controlling apparatus for a developing roller is provided to uniformly control an amount of developer deposited on the developing roller and a developer controlling method thereof. The apparatus includes a sensing part having a first sensor which senses a conductivity of a liquid developer and a second sensor which senses a density of the liquid developer. A control part controls a voltage applied to the developing roller and/or a deposit roller according to the conductivity and the density sensed by the sensing part.