Specifications

2.3 Xerographic Process
The two diodes connect the axial shafts to ground and establish a strong
negative cleaning charge on the upper roller. The upper metal fusing roller
accumulates the charge from the residual transfer charge that adheres the
unfused toner to the sheet. This negative charge repels the like-charged toner
particles from the upper roller thus making it difficult for the toner to stick to
the fusing rollers.
The nonstick coating on the upper roller also helps prevent toner from sticking.
Technical Description 2–19