problem imap_headerinfo

I get a *Catchable fatal error*: Object of class stdClass could not be converted to string on this line $mail_head = imap_headerinfo($conn, $i); if I remove it it works fine what would be casing this I really need to read the header. I am using php version 5.2.5 $conn = @imap_open("{" . $bouncer['host'] . ":" . $bouncer['port'] . "/" . $bouncer['mailtype'] . "/notls}" . $bouncer['mailbox'], $bouncer['username'], $bouncer['password']);

    $headers = @imap_headers($conn);
       if ($headers) {
         $email_count = sizeof($headers);
         for($i = 1; $i <= $email_count; $i++) {
              # Check the body against all saved patterns
              $mail_head = imap_headerinfo($conn, $i);                   $mail_body = imap_fetchbody($conn, $i, 1);
               echo "mail head: $mail_head<br>\n";
               echo "mail body: $mail_body<br>\n";