Will window.print() postback in ASP

Question

I have a form that updates a database when this form is printed. For some reason i'm not picking up a post back when my form is submitted

ASP:

    ' -----------------------------------------------------------------------------
    '  update form as printed
    ' -----------------------------------------------------------------------------
    If IsPostBack Then
      Dim dtrw3 As DataRow
      For Each dtrw3 In ds.Tables(3).Rows
           Update_As_Printed(dtrw3("frm_trans_id"))
      Next
    End If
    ....... 
           some stuff 
    ......... 
    conSql.Close()

Javascript

function printpage() {
  window.print();
  document.forms["frm_trans"].submit();
}

HTML

<form runat="server" id="frm_trans">
<center>
<table class='noprint' >
   <tr>
    <td align=center>
          <input type='button' name='button_print' value="Print and Mark As Printed" onclick="javascript:printpage()"><br> 
     </td>
   </tr>
</table>
         ............................
         ............................
         ............................
</form>