Controlled transfer nip for an electrophotographic device and method of using same
View Patent ↗An imaging apparatus, including a transfer roll; and first and second rolls, each first roll and second roll being disposed relative to the transfer roll, the second roll forming a transfer nip with the transfer roll and the first roll being disposed upstream relative to the second roll in a media feed direction. During a toner transfer operation, the transfer roll is coupled to a predetermined voltage and the first and second rolls are coupled to at least one voltage reference so that an electric field is generated between the transfer roll and the first roll and between the transfer roll and the second roll, the first roll being associated with an electrical characteristic such that the electric field generated between the transfer roll and the first roll is limited during the toner transfer operation relative to the electric field generated between the transfer roll and the second roll.
1. An electrophotographic imaging apparatus, comprising:
a voltage source;
electrical ground;
a shunt resistor having a relatively large resistance of at least 1 megohm;
an intermediate transfer member (ITM) belt forming an endless loop having an inner surface and an outer surface, the ITM belt for receiving and transferring an image of toner;
a transfer roll disposed along the outer surface of the ITM belt; and
a drive roll and a backup roll, each of the drive roll and the backup roll being disposed along the inner surface of the ITM belt opposite to the transfer roll, the backup roll forming a transfer nip with the transfer roll and the drive roll being disposed upstream relative to the backup roll in a media feed direction,
wherein the transfer roll is coupled to the voltage source having a predetermined voltage and each of the drive roll and the backup roll is coupled to said electrical ground, the drive roll being connected to said electrical ground via the shunt resistor thereby having a higher voltage potential closer to the predetermined voltage during use in comparison to the backup roll having a lower voltage potential closer to electrical ground such that a majority of toner of the image moves from the ITM belt toward the transfer roll nearer the backup roll than the drive roll.