Prova questo....

File : test2031a.html
codice:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<html>
<head>
<title>Untitled</title>
<script language="JavaScript" type="text/javascript">
<!--
function printPreview() {
 window.open("test2031b.html","pippo","toolbar=no");
}
//-->
</script>

</head>
<body>
<textarea id="my_textarea" rows="20" cols="80"></textarea>

<input type="button" value="Print preview" onclick="printPreview()">
</body>
</html>

File : test2031a.html
codice:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<html>
<head>
<title>Untitled</title>

<style type="text/css">
<!--
.btn {}
-->
</style>


<script language="JavaScript" type="text/javascript">
<!--
function myBeforePrintFunction() {
 document.all.btn.style.visibility = "hidden";
} // function myBeforePrintFunction()
function myAfterPrintFunction() {
 document.all.btn.style.visibility = "visible";
} // function myAfterPrintFunction()

window.onbeforeprint =  myBeforePrintFunction;
window.onafterprint  =  myAfterPrintFunction;
//-->
</script>

</head>
<body>
<input class="btn" type="button" name="btn" value="Print" onclick="window.print();"/>


<script language="JavaScript" type="text/javascript">
<!--
var textToPrint = window.opener.document.getElementById('my_textarea').value;
re              = /\n/gi;
var textToPrint = textToPrint.replace(re,"
");
document.write(textToPrint);
//-->
</script>

</body>
</html>