uses
 printers;
{$R *.DFM}
procedure StartPrintToFile(filename: string);
var
 CTitle: array[0..31] of Char;
 DocInfo: TDocInfo;
begin
 with Printer do
 begin
  BeginDoc;
  { Abort job just started on API level. }
  EndPage(Canvas.handle);
  Windows.AbortDoc(Canvas.handle);
  { Restart it with a print file as destination. }
  StrPLCopy(CTitle, Title, SizeOf(CTitle) - 1);
  FillChar(DocInfo, SizeOf(DocInfo), 0);
  with DocInfo do
  begin
  cbSize := SizeOf(DocInfo);
  lpszDocName := CTitle;
  lpszOutput := PChar(filename);
  end;
  StartDoc(Canvas.handle, DocInfo);
  StartPage(Canvas.handle);
 end;
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
 StartPrintToFile('C:\temp\temp.prn');
 try
  Printer.Canvas.TextOut(100, 100, 'Hello World.');
 finally
  Printer.endDoc;
 end;
end;