I have developed a Jasper report and I want it to be printed in duplex without changing the settings on the printer. Is there any configuration in the JR that can print in double-sided?
Unfortunately, no. Duplex pring is a feature of a printer and is printer specific.
However, it is easy to customize JasperReports to enable exporting to pdf that merges different layout report on each side of the paper. Unfortunately, other export types such as xlsx does not support it so it's a customer specific modification and can not be a general feature addition to JasperReports.
It should be just an flag within the PrintRequestAttributeSet when I remember right. So you needn't to change the Printer settings in generall. So this is always the decission of the user how a JasperPrint will be sent to the printer and not defined in the design mode. (also like in MS Word... you PRINT it duplex and don't set an option to the word doc itself!)
hth + regards