Patent ID: 7643781
Filing Date: 2010-01-05
Classification: G03G

Abstract:
1. A transfer device that transfers an image formed on each of a plurality of image-carrier rotating members onto a transfer belt by applying a bias voltage to image-carrier rotating members, the image-carrier rotating members including a first image-carrier rotating member that is located most upstream along a moving direction of the transfer belt, the transfer device comprising: a bias-applying rotating member corresponding to each of the image-carrier rotating members, each of the bias-applying rotating members being positioned opposite to a corresponding one of the image-carrier rotating members, the transfer belt being interposed between the bias-applying rotating member and the corresponding image-carrier rotating member, and the bias-applying rotating member configured to apply a bias voltage to the transfer belt whereby the image formed on the corresponding image-carrier rotating member is transferred onto the transfer belt, wherein the first image-carrier rotating member is arranged so that a rotation axis of the first image-carrier rotating member is positioned closer to the transfer belt and displaced from a line on which rotation axes of other image-carrier rotating members fall, each of the bias-applying rotating members being displaced downstream of the corresponding image-carrier rotating member along the moving direction of the transfer belt, and a line on which a rotation axis of each of the bias-applying rotating member and a rotation axis of the corresponding image-carrier rotating member fall is orthogonal to the moving direction of the transfer belt, the first image-carrier rotating member carries an image in a first color, the transfer device further comprising a mechanism that removes the transfer belt from contact with other bias-applying rotating members corresponding to said other image-carrier rotating members to transfer only the image in the first color onto the transfer belt, and a contact angle which corresponds to a width of the transfer belt which is in contact with the first carrier rotating member is constant when the transfer belt is in contact with the other bias-applying rotating members and when the transfer belt is removed from contact with the other bias applying rotating members due to contact of the transfer belt with the bias-applying rotating member that corresponds to the first carrier rotating member.