Fusing And Paper Exit; Overview - Ricoh FW780 Service Manual

8.

FUSING AND PAPER EXIT

8.1 OVERVIEW

[B]
After separation from the drum, copy paper rides on the transport plate [A]. The
small separation rollers [B] hold the paper against the transport plate so that the
back curled paper is straightened before it enters the fusing section.
Two rollers fuse the image to the copy paper by applying heat and pressure. The
hot roller [C] is made of carbon-teflon and the pressure roller [D] is made of
silicone rubber. Pressure is constantly applied by the pressure levers at the ends
of the fusing unit.
The fusing lamp [E], which is located at the hot roller axis, turns on and off to
maintain the operating temperature. The temperature control circuit on the main
board monitors the surface temperature of the hot roller and the pressure roller
through a thermistor [F and G respectively].
There are three operating temperature settings: normal, high, and low. The
normal setting has a choice of 7 temperature settings, adjustable by SP1 or key
operation. The high setting has a choice of 4 temperature settings. The low
setting also has a choice of 4 temperature settings.
The hot roller strippers [H] separate the copy from the hot roller and direct it to
the fusing exit rollers [I].
The thermofuse provides backup overheat protection. (See the section on fusing
temperature control.)
The fusing exit sensor [J] is used for jam detection.
A163
[F]
[E]
[A]
2-27
[C]
[J]
[H]
[I]
[G]
[D]
SM