从数据库中按名称保存PDF

I am saving my records as PDF but I want them saved by using name_empnumber like abc_123

I am using the code below and library TCFPDF

if (isset($_POST['submit'])){
    require_once 'includes/practice.php';
//practice.php is using library tcfpdf

$pdf->SetFont('times', '', 15);

$tb1 = '</br></br>  

                            <b>2-  Printer:</b><br /><br />
                            <table cellspacing="0" cellpadding="0" border="1"> 

                                <tr style="background-color:#f7f7f7;color:#333; ">


                                    <td width="300">SN</td>
                                    <td width="300">TYPE</td>

                                </tr>

                            </table>';

$result= mysql_query("SELECT * FROM accessories where emp_number='".$emp_number."' && is_accessory='Printer'");

 while($row = mysql_fetch_assoc($result)){
$tb2 = '<table cellspacing="0" cellpadding="2" border="1"> 
                <tr> 

                                <td width="300">'.$row['serial'].'</td>
                                <td width="300">'.$row['model'].'</td>        
                </tr>
            </table>';

            $tb1 = $tb1.$tb2;
        }


 $pdf->writeHTML($tb1, true, false, false, false, '');

      ob_end_clean();
      $pdf->Output('Report.pdf', 'D');
}

See this is saving as Report.PDF.

I want to save as name_empnumber.pdf like abc-123.pdf