Patent ID: 7233750
Filing Date: 2007-06-19
Classification: G03G

Abstract:
1. An image forming apparatus comprising: an image bearing member; a first developing device to which a first developing voltage is applied, thereby developing an electrostatic latent image and forming a first color toner image on said image bearing member; a second developing device to which a second developing voltage being different from the first developing voltage is applied, thereby developing an electrostatic latent image and forming a second color toner image on said image bearing member; a primary transfer member to which a primary transfer voltage is applied, thereby primarily transferring the first color toner image and the second color toner image to an intermediate transferring member; a secondary transfer member which secondarily transfers the first color toner image and the second color toner image from the intermediate transferring member to a recording material; and determination means which determines a primary transfer voltage for primarily transferring the first color toner image on the basis of a voltage-current characteristic where a test bias is applied to the primary transfer member in a state that said first developing voltage is applied to said fist developing device, and determines a primary transfer voltage for primarily transferring the second toner image on the basis of a voltage-current characteristic where a test bias is applied to the primary transfer member in a state that said second developing voltage is applied to said second developing device.