With Tableau Server, you can access your published workbook in a pdf format with this URL:
http://nameofyourtableauserver/views/NameOfYourWorkbook/NameOfYourView.pdf
Simply, the url is the url of your view + you add ".pdf".
The pdf file will be generated dynamically when accessing the URL.
Another option is to program your own script with tabcmd. You can have more info on tabcmd here: http://kb.tableausoftware.com/articles/knowledgebase/using-tabcmd