What type of object has a scroll bar? A portal or a field? If a portal, is there just one portal or several?
There are ways to set up a layout for printing that will allow you to get all the data to print, but the precise method used will depend on the design details of your layout.
If this is a single portal with a scroll bar, take a look at how an invoice is printed from a FileMaker Invoice starter solution.
This is just one portal. (Sorry, I was unable to find FileMaker Invoice starter solution.)
Pull down the file menu and select "New From Starter Solution".
The method used in that starter solution is that you set up a list view layout based on the portal's table. You then use a script from your current layout that pulls up a found set of the current record's set of portal records on that layout in order to print them. Fields from your current layout's table can be included in the header or footer of this layout.
To pull up the correct portal records on this other layout, you can either use Go to related records or a scripted find.