The printed report is internally exported to PDF which is page oriented format and it is normal for the report to be paged. The output of a report rendered in different formats differs because medias are quite different. For example HTML/Excel is dedicated to displaying information on screen and the page is infinite by width and height; in contrast PDF supports physical pages and is meant not only for reading on screen but for printing.
According to whether the format supports physical pages, we separate the export formats on two groups: page-oriented (PDF, Image (print preview), print, XPS, RTF) and non-page oriented (HTML/MHTML, Excel, CSV).
For the page-oriented formats the content layout is on horizontal and vertical pages according the the page settings of the report, while for the rest of the formats take into considerations other characteristics of the media. More info is available in the Design Considerations for Report Rendering
the Telerik team