If you export into CSV (it works in similar way for other formats too) you usually need to avoid export of some fancy headers, page headers etc. Because it would break CVS data alignment. Solution is taken from this stackoverflow answer.
Add property to the main report:
<property name="net.sf.jasperreports.export.csv.exclude.origin.band.1" value="title"/>
Names of report parts are taken from XML tags in jrxml source file: