Data Table Print Button

My JS is here:

 $(document).ready(function () {
        $("#GridViewReport").prepend($("<thead></thead>").append($("#GridViewReport").find("tr:first"))).dataTable({
            "paging": true,
            "ordering": true,
            "order": [[7, "desc"]],
            "lengthMenu": [[10, 25, 50, 100, -1], [10, 25, 50, 100, "All"]],
               buttons: [
            'print'
        ]
        });
    });

I am not getting any errors in my console, but the print button is still missing on my page!