Configuring Printing in the Portal 
You can configure Web Dynpro iViews/pages so that portal users can print the content of the iViews/pages by using the print function of their Web browser.
During runtime, clicking the Print option in the iView/page tray displays the content of the iView in a new window. Clicking the browser Print button actually prints the content.
For each iView/page that you want to enable for printing, set the Show 'Print' Option property (Appearance – Tray category) to Yes. This adds a Print option to the iView/page tray.
For information on setting properties, see Property Editor.
For user information, see Printing Portal Content in the Getting Started guide.