Ricoh FT4430 Service Manual page 230

16 April '88
The DF has its own CPU which controls all of the DF functions. The DF CPU
communicates with the copier through an interface board [A] and serial
interface bus [B]. Fiber optics . [C] are used for the serial interface bus
because they are unaffected by electrical noise.
When an original is set on the original table, the original sensor [S34] is
activated. The DF CPU then selects either the ADF or SADF mode depending
on the number of originals set. If one original is set, SADF is selected. If more
than one original is set at the same time, SADF changes to ADF when the
second original starts to feed.
The DF CPU energizes the stopper and pick-up solenoids, and then turns on
the feed-in motor [Ml 4]. The feed [D] and friction rollers [E] separate and
feed an original to the registration rollers [F].
A short time after the original reaches the registration roller the DF CPU turns
on the belt drive motor [M 16] and energizes the registration solenoid. The
time lag enables the original skew to be corrected. The belt then feeds the
original to the exposure glass, while the CPU counts the pulses of the Ml 6
encoder. At the proper time, the CPU turns off Ml 6.
When the DF CPU receives the feed-out signal from the copier, it turns on the
feed-out motor [M 15] until the exit sensor [S38] is eactuated by the trailing
edge of the original.
As the exit sensor is inside the exit unit, the trailing edge of the original is still
in the exit unit. After
out completely. This stacks the originals tidily.
second, the CPU turns on Ml 5 to feed the original
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