I am using TCPDF library to generate a PDF. In that I have HEADER image and a table in content area as shown below screenshot:

As you are able to see that table is at left of the PDF, i want it to be at center.
I tried to change the value configuration file(tcpdf_config_alt.php) file by changing value of define ('PDF_MARGIN_LEFT', 5); but what is happening is the header image is also moving to right as in following screenshot.

but what i want is in following screen shot:
 Then I tried to move the table in my html code but still the table doesn't come to center of PDF. The
Then I tried to move the table in my html code but still the table doesn't come to center of PDF. The margin-left i given to table is not appied.
HTML code in TCPDF php file:
$tbl =  '<html>';
$tbl .= '<body>';
$tbl .= '<table style="margin-top:10px; margin-left:300px;" width="50%" border="1" align="left" cellpadding="5" cellspacing="0">';
$tbl .= '<tr>';
$tbl .= '<td><b>Agent Name</b></td>';
$tbl .= '<td><b>'.$agent_name.'</b></td>';
$tbl .= '</tr>';
$tbl .= '<tr>';
$tbl .= '<td><b>Port</b></td>';
$tbl .= '<td>'.$port.'</td>';
$tbl .= '</tr>';
$tbl .= '<tr>';
$tbl .= '<td><b>Address</b></td>';
$tbl .= '<td>'.$address.'</td>';
$tbl .= '</tr>';
$tbl .= '<tr>';
$tbl .= '<td><b>Telephone</b></td>';
$tbl .= '<td>'.$tel.'</td>';
$tbl .= '</tr>';
$tbl .= '<tr>';
$tbl .= '<td><b>Fax</b></td>';
$tbl .= '<td>'.$fax.'</td>';
$tbl .= '</tr>';
$tbl .= '<tr>';
$tbl .= '<td><b>Contact</b></td>';
$tbl .= '<td>'.$contact.'</td>';
$tbl .= '</tr>';
$tbl .= '<tr>';
$tbl .= '<td><b>Email ID</b></td>';
$tbl .= '<td>'.$email_id.'</td>';
$tbl .= '</tr>';
$tbl .= '<tr>';
$tbl .= '<td><b>Website Address</b></td>';
$tbl .= '<td>'.$website_address.'</td>';
$tbl .= '</tr>';
$tbl .= '</table>';
$tbl .= '</body>';
$tbl .= '</html>';
so please can anyone help me to resolve this issue. Thanks in advance.