枚举所有打印机,按名字查询uses
  winspool, printers;...
procedure TForm1.Button1Click(Sender: TObject);
var
  HPrinter: THandle;
  Forms: array of TFormInfo1;
  Count, Needed, Returned: DWORD;
  i: Integer;
begin
  Memo1.Clear;
  if OpenPrinter(nil, HPrinter, nil) then begin
    try
      if not EnumForms(HPrinter, 1, nil, 0, Needed, Returned) then begin        // we should fail here since we didn't pass a buffer
        if GetLastError <> ERROR_INSUFFICIENT_BUFFER then
          RaiseLastOSError;        Count := (Needed div SizeOf(TFormInfo1)) + 1;
        SetLength(Forms, Count);
        if EnumForms(HPrinter, 1, @Forms[0], SizeOf(TFormInfo1) * Count, Needed,
            Returned) then begin
          if Returned < Count then
            SetLength(Forms, Returned);
          for i := 0 to Returned - 1 do begin
             Memo1.Lines.Add(Format('Paper name: %s,   Paper size: %dmm x %dmm',
                            [Forms[i].pName,
                             Forms[i].Size.cx div 1000,
                             Forms[i].Size.cy div 1000]))
          end;
        end else
          RaiseLastOSError;
      end;
    finally
      ClosePrinter(HPrinter);
    end;
  end else
    RaiseLastOSError;
end;