Original Size Detection - Ricoh FT6645 Service Training Manual

8. ORIGINAL SIZE DETECTION

[F]
The DJF detects original width through the on/off combination of the three
original width sensors -1 [A], -2 [B], -3 [C], it also detects the original length
through the use of the registration sensors -1 [D], -2 [E] and the pulse count
sensor [F].
The DJF CPU counts the pulses between registration sensor - 2 [E] on timing
and registration sensor - 1 [D] off timing.
Based on this pulse count, the CPU determines the original length.
The reason for using two registration sensors are:
1) Registration sensor -2 [E] is used to stop the pre-fed original to wait until
the previous original is fed out. For precise control, the original stop
position must be after the pull out rollers [G]. Therefore, registration
sensor -2 is placed after the pull-out roller.
2) Registration sensor -1[D] checks the trailing edge of the original. This
check is used to place the original on the exposure glass.
A certain distance is required between the sensor and the original scale.
Therefore, registration sensor -1 is placed 34.9 mm before sensor -2.
The original size is determined by the combination of the detected original
width and the length.
STM
[D]
[G]
[A]
[B]
3-17
[E] [E]
[C]
FT6645/6655/6665