Did you try using the browser native print function ? In my experience, using G Chrome, the results are pretty good. You can adjust the portion to print using the "scale" option of the printing window.
The icon bar and other controls do not print anyway, apart from some little graphical elements and the title and the mention "All changes are saved".
I accompany Christophe here. AFAIK, there is no separate print function in Xmind Cloud, rather you use the browser's one. And note those web applications that have a print button use also the browser's, because a web page doesn't have a direct access to any printer (that would be a security risk).