Patent ID: 7447454
Filing Date: 2008-11-04
Classification: G03G

Abstract:
1. An image forming apparatus for forming an image on a sheet comprising: a transfer member that transfers a developer image onto the sheet to form the image on the sheet and comes in contact with the sheet when the developer image is transferred onto the sheet; a bias applying unit that applies a transfer bias to the transfer member; a selection unit that selects a width of the sheet; and a transfer bias control unit that controls the transfer bias to be applied to the transfer member by the bias applying unit, wherein a longitudinal length of the transfer member is formed to be shorter than a width of the sheet having a maximum width on which the image is to be formed with the image forming apparatus, the transfer bias control unit controls the bias applying unit so that a transfer bias is applied according to a control method differing depending on whether or not the width of the sheet to be used for transferring is longer than the longitudinal length of the transfer member, the transfer bias control unit controls the bias applying unit with a first control method when the width of the sheet to be used is longer than the longitudinal length of the transfer member, and controls the bias applying unit with a second control method when the width of the sheet to be used is shorter than the longitudinal length of the transfer member, and a switching element that switches the transfer bias control unit between a constant current control and a constant voltage control in accordance with the selected width of the sheet.