Solution:

Load the sheets the other way up.

Print the image. Has the problem been resolved?

In the 03: [Machine: Paper Feed/ Output] group on the [Adjustment Settings for Operators] menu, set 0301: [Correct Output Paper Curl: 1 Sided: Face Up], 0302: [Correct Output Paper Curl: 1 Sided: Face Down], or 0303: [Correct Output Paper Curl: 2 Sided] to "U Curl Correction Level".

Alternatively, in [Advanced Settings] for the custom paper, select 1311: [Correct Paper Curl], and then specify "U Curl Correction Level".

Select "Large", "Medium" or "Small" to control the level of decurling as required.

Print the image. Has the problem been resolved?