Solution:

In the 03: [Machine: Paper Feed/ Output] group of the [Adjustment Settings for Skilled Operators] menu, set 0301: [Adjust Paper Curl] to [Adjust Curl].

If "Curl: Off" is selected, change the value to Curl: Weak". If "Curl: Weak" is selected, change the value to "Curl: Strong".

If you cannot remove back curls, print with the printed side face up for single-sided printing.