Correct way to send commands directly to printer!

Question

Ok, here is how i do it:

procedure TMainWindow.btnRawPrintClick(Sender: TObject);
begin
  BeginPrint;
  SendStr(#27#69);
  SendStr('MyData');
  SendStr(#10);
  EndPrint;
end;

procedure TMainWindow.SendStr(Text: String);
var
  i: Integer;
  data : Array of Char;
begin
  for i := 1 to Length(Text) do
  begin
    SetLength(data,i);
    data[Pred(i)] := Text[i];
  end;

  if (PrintRawData(printHandle,
                   data,
                   Length(data)) < 0) then begin
    ShowMessage('PrintRawData Failed');
    EndRawPrintPage(printHandle);
    EndRawPrintJob(printHandle);
    exit;
  end;
end;

procedure TMainWindow.BeginPrint;
begin
  printHandle := StartRawPrintJob('EPSON TM-T70 Receipt','ESDPRT001','Test Document');

  if printHandle < 0 then
  begin
    ShowMessage('StartRawPrintJob Failed!');
    exit;
  end;

  if (StartRawPrintPage(printHandle) < 0) then begin
    ShowMessage('StartRawPrintPage Failed!');
    EndRawPrintJob(printHandle);
    exit;
  end;
end;

procedure TMainWindow.EndPrint;
begin
  if (EndRawPrintPage(printHandle) < 0) then begin
    ShowMessage('EndRawPrintPage Failed');
    EndRawPrintJob(printHandle);
    exit;
  end;

  if (EndRawPrintJob(printHandle) < 0) then begin
    ShowMessage('EndRawPrintJob Failed');
    exit;
  end;
end;

Also i changed a little code that i took from here:

function PrintRawData(hPrn : THandle;
                      Buffer : pointer;
                      NumBytes : SpoolInt) : integer;
{$IFDEF WIN32}
var
  BytesWritten : DWORD;
 {$ENDIF}
begin
  NumBytes := NumBytes * 2;    //<-- I added this line
  ...

However, something is wrong as some commands (escape sequences) don't work as expected!