Ricoh SP 8400DN Field Service Manual page 1398

7.Detailed Descriptions
Transfer Roller Unit Charge
The high voltage supply board supplies a positive current to the transfer roller [A], which attracts the toner from
the drum onto the paper. The current depends on the paper width, paper type, and paper feed tray.
The curvature of the drum and the discharge plate [B] help the paper to separate from the drum. The high voltage
supply board also supplies a negative dc voltage to the discharge plate [B], which helps the paper to separate from
the drum.
Transfer Roller Contact and Release Mechanism
The transfer roller contact and release mechanism prevents dirt and distortion. A transfer roller contact cam [A] in
the front right side of the mainframe is driven by the transfer roller contact motor [C]. The transfer roller contact
cam moves the transfer roller contact arm [C] by its rotation. The transfer roller [D] and OPC drum [E] are
separated by the movement of the transfer roller contact arm during process control, discarding toner, or when the
main power is turned off.
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