If your question is regarding the old ASP.NET ReportViewer, note that the print operation depepnds on the browser's Adobe PDF plugin. If the plugin is enabled and updated correctly, the print operation will succeed, otherwise it will fallback to PDF export. For more details check the True Print help article.
New HTML5/JS REPORT VIEWER with MOBILE AND TOUCH SUPPORT available in Telerik Reporting Q3 2013! Get the new Reporting version from your account or download a trial.