phpChart_Lite water mark displayin in graph

Question

I am working with PHP graph and using new C_PhpChartX.

PHP Chart Lite.

Graph is displaying very well, but watermark behind graph not being removing.can anone help me how can i remove watermark from graph as i want to use it for live website.

Below is sample code which remain use further Js for render graph.

$l1 = array(20,18, 36, 14, 11,18,27);
$l2 = array(array(2, 14), array(7, 2), array(8,5));
$l3 = array(21, 21, 21, 21, 21, 21, 21, 21, 21, 21);


$pc = new C_PhpChartX(array($l1,$l2,$l3),'basic_chart');
$display = $pc->draw(400,400);