delphi中的语句SendToPrinter([$1B,$7A,$31]);

给你一个源码看看吧：
unit Unit1;

interface

uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
StdCtrls,Printers,winspool, ExtCtrls;

type
TForm1 = class(TForm)
Button1: TButton;
Button2: TButton;
Button3: TButton;
Button4: TButton;
Button5: TButton;
ComboBox1: TComboBox;
Button6: TButton;
procedure Button1Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
procedure Button4Click(Sender: TObject);
procedure Button3Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;