Ricoh SP 8400DN Field Service Manual page 2190

2.Detailed Descriptions
Folding Mechanism
By the bidirectional movement of the roller, the paper is fed to the fold position, and the paper stays in close
contact with the roller when folding. This enables precise folding regardless of the characteristics of the paper.
After feeding the paper to the 1st fold roller (F/R), the machine can control precisely where to stop the paper [A]
by using a proportional-integral-differential (PID) controller.
The distance [D] between the folding position [C] and the fold-assessment position [B] is short (about 30 mm
regardless of the fold type or paper size). Furthermore, folding is performed with the paper in contact with the
folding roller, preventing arching regardless of the paper curl, thickness, grain, and stiffness.
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