[Phenomenon]
Abnormal noise such as a resonant sound has occurred in the paper exit section during pre-running in the field.

[Cause]
Currently, knurling grooves on the idling roller in the paper exit section are in the same phase on both the left and right sides. (Ridges and roots are located in the same position on both the left and right sides.)
Abnormal noise occurred due to the vibration generated when the ridges and the roots are slid into each roller alternately while the idling roller is being rotated during pre-running
This noise will become louder only when resonance occurs while paper has run out during pre-running.
This phenomenon will occur in very rare cases depending on the combination of the rollers.