TableTools Print displays no records

I'm using an Ajax datasource to bind my datatable however when I click the "Print" button from TableTools, the grid is displayed in print view with no records. I can see that the same method used to load the data during draw is being called on Print, with the same records returned, but they're not displaying in print view.

I'm using 1.9.4 of DataTables and 2.1.4 of TableTools.

Thanks.