Patent ID: 6430379
Filing Date: 2002-08-06
Classification: G03G

Abstract:
An image forming apparatus comprising:an image carrier on which a toner image corresponding to image information is formed; an intermediate transfer medium disposed to face the image carrier; a primary transfer unit that transfers the toner image on the image carrier onto the intermediate transfer medium; a secondary transfer unit that transfers the toner image on the intermediate transfer medium onto a transfer medium, the secondary transfer unit comprising a secondary transfer member having a contact transfer member which is disposed in contact with at least the surface of the intermediate transfer medium, a bias applying unit that applies a transfer bias to transfer the toner image on the intermediate transfer medium through the secondary transfer member to the transfer medium and an inverse transfer bias having the opposite polarity to the transfer bias, and a bias switching unit which switches the bias to be applied by the bias applying unit to apply the transfer bias to an image transfer area on the intermediate transfer medium and apply the inverse transfer bias to at least a part of an image non-transfer area on the intermediate transfer medium; a disturbing member which is formed of an insulator disposed in contact with the contact transfer member and disturbs the toner adhering to the contact transfer member; a resistance measuring unit that measures a composite resistance of secondary transfer area; and an inverse bias setting unit that sets the magnitude of the inverse transfer bias of the bias applying unit on the basis of the composite resistance measured by the resistance measuring unit.