Ricoh Gestetner 5450, Service Manual, Page: 101 / 315

1 July, 1998 PRINTING AND PRESSURE CYLINDER
2-73
Detailed
Descriptions
2.7.5 PAPER FEED CONTROL MECHANISM
Paper Feed Start Timing Detection
There are two actuators on the rear flange of the pressure cylinder. The two
actuators activate the paper feed start sensor [A], to determine the start timing of
the paper feed motor and the registration motor. (For details, refer to the Paper
Feed section – Paper Feed Mechanism, and Paper Registration Mechanism.)
Detection and Feedback of Pressure Cylinder Rotation Fluctuation
Since the pressure cylinder does not have a perfectly circular cross-section, the
rotation speed tends to fluctuate.
The feed encoder [B], which is a photointerrupter, is activated by the encoder plate
[C] at the rear of the pressure cylinder, generating a pulse signal. The CPU
monitors this signal to detect fluctuations in the pressure cylinder rotation.
Depending on the detected fluctuation, the registration motor start timing is
adjusted so that the leading edge of the paper is precisely caught by the paper
clamper [D] on the pressure cylinder.
C229D022.WMF
C229D068.WMF
[A]
[B]
[C]
[D]
Rear
Front