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.
Note:
In the previous multi-fold unit, the folding position was determined by the stopper [B]. The distance [A] from the folding position [C] to the stopper is long (about 100 to 240 mm, depending on the fold type and paper size). Furthermore, the arch of the paper in the space to the stopper was influenced by the paper curl, thickness, grain, and stiffness.
Even if the stop position was accurate, the arch of the paper influenced the fold length.