Patent ID: 7039349

Claim:
An image forming apparatus capable of forming images on both surfaces of a recording medium, said image forming apparatus comprising: an image carrier; and an image transferring device including a first and a second intermediate image transfer body whose surfaces are endlessly movable in contact with each other while forming a nip therebetween, said image transferring device being configured to transfer, while conveying the recording medium nipped by said nip toward a side downstream of said nip in a direction in which said surfaces are endlessly movable, a first toner image transferred from said image carrier to said second intermediate image transfer body via said first intermediate image transfer body beforehand to a first surface of said recording medium and transfer a second toner image transferred from said image carrier to said first intermediate image transfer body to a second surface of said recording medium; wherein first-surface image transferring means and second-surface image transferring means for respectively transferring the first toner image and the second toner image to the first surface and the second surface of the recording medium, respectively, comprise two pairs of conductive rollers that face each other via the surfaces of said first intermediate image transfer body and said second intermediate image transfer body at the nip, and wherein two of said conductive rollers associated with said second intermediate image transfer body comprise transfer rollers respectively applied with one and the other of biases a and b of opposite polarities.