Master Feed Mechanism - Ricoh C231 Service Manual

2.4.2 MASTER FEED MECHANISM

C231D536.WMF
A stepper motor (the master feed motor [A]) drives the platen roller [B]. The thermal
head is pressed against the platen roller by the pressure springs. The pressure is
applied when the master set cover, which includes the platen roller, is closed.
After the master is ejected, the drum stops at the master feed position and the
master clamper opens, ready to clamp the new master.
The leading edge of the master is stopped on the guide plate after the last master
cutting operation or after a new master roll has been installed. The master is then
fed for 52.4 mm and stopped briefly to synchronize with original feed. The master is
fed for a further 67.5 mm before the master clamper is closed. Since the clamper
closes after the master's leading edge reaches the clamper, a buckle [C] is made in
the master above the master feed guide. This buckle absorbs the shocks from the
master clamping operation.
The drum then turns intermittently in the slowest mode (30 rpm) to wrap the master
around the drum. The intermittent rotation keeps a buckle in the master above the
master feed guide to absorb shocks from the wrapping operation. The tension roller
[D] is pressed against the guide plate to keep the master under tension during the
master wrapping operation.
SM
[B]
[A]
[C]
2-25
MASTER FEED
[D]
C231D535.WMF
C231/C237/C238