Patent ID: 6243543
Filing Date: 2001-06-05
Classification: G03G

Abstract:
A developing device comprising:charging means for uniformly charging a surface of an image carrier during its movement;exposure means for exposing to form an electrostatic latent image on the charged image carrier;developing means provided facing the image carrier for supplying developing agent to the image carrier to develop the electrostatic latent image, the developing means including a first developing roller and a second developing roller arranged at the down stream side of the first developing roller in the moving direction of the image carrier;bias applying means for applying a bias voltage to the first and second developing rollers;control means for controlling the bias applying means to apply a reverse bias voltage of a reverse polarity opposite to the polarity of the charged image carrier to the first and second developing rollers until the charged area on the image carrier reaches the position facing the first developing roller, and then apply a regular bias voltage of the same polarity as the charged image carrier to the first developing roller when the leading edge of the charged area on the image carrier passes the position facing the first developing roller after the charging to the image carrier has started; anddriving means for starting to drive the developing means before the leading edge of the electrostatic latent image formed on the image carrier passes the position facing the first developing roller after the control means controls the bias applying means to apply the regular bias voltage.