Printing Pressure Mechanism - Ricoh C231 Service Manual

2.6.5 PRINTING PRESSURE MECHANISM

[E]
[A]
[H]
While the machine is not in the printing cycle, the printing pressure release
solenoids [A] are off and the stoppers [B] lock the brackets [C] to keep the press
roller [D] away from the drum.
When the 1st sheet of paper is fed, the solenoids are energized but the brackets
are still locked by the stoppers due to strong tension from the springs [E]. When the
high points of the cams [F] on the front and rear drum flanges reach the cam
followers [G] on both sides of the press roller shaft, a small clearance is made
between the stoppers and the brackets.
There is one solenoid each on the operation side and non-operation side. The two
solenoid plungers are pulled down at the same time releasing the stoppers from
the brackets. Printing pressure is applied by the tension of the springs when the
cam followers are at the high points of the cams.
During the printing cycle, the solenoids stay energized. However, if paper does not
reach the registration sensor [H] at the proper time (when the cam follower is on
the high point of the cam), the solenoids are de-energized to lock the brackets.
The printing pressure is released when the cams push the cam followers down so
that the press roller does not come in contact with the master clamper [I].
After printing is finished, the solenoids are de-energized and the stoppers are
returned by the tension of the springs. Before the drum returns to the home
position, the brackets are locked by the stoppers again when the cams push the
cam followers.
SM
[I]
[G]
2-39
PAPER FEED
[F]
[D]
[B]
[C]
[A]
[E]
[F]
[ I ]
C231D546.WMF
C231/C237/C238