The magnitude and polarity of the voltage on the fuser roll surface is
controlled by either electronic charge application means or by applying
charge control agents to the fuser. For negative toner, the fuser roll
voltage must also be negative (and visa versa). This will repel the
negative toner at the entrance to the fuser nip, prevent the toner from
transferring to the fuser roll at the entrance of the fuser nip and
preclude the formation of NVO and consequently prevent MOC.