| 摘要 |
PURPOSE:To obtain the fixing device capable of preventing offset even when a fixing roller, etc., are variously triboelectrified caused by a transfer material. CONSTITUTION:The surface potentials of a pressure roller, etc., are measured by providing a surface potential measuring device 20. Also, this fixing device is provided with a control part 21 which, in response to a signal from the surface potential measuring unit 20, changes a speed at which the cleaning web of a web cleaner 12 for the fixing roller is fed, or changes a bias voltage for the prevention of offset which is applied to the fixing roller. Thus, even if the fixing roller, etc., are electrified by frictional electrification to such a degree that offset is easily caused, the offset of toner to other transfer sheet can be effectively prevented via the fixing roller, etc. |
