Format text in bluetooth printer

actually, I have to implement a module the which connect to a BT termical printer and print in it. I have a simple but functionally example, it works with the printer. The problem is that these text are printed in plain text, and i have to give it format, bold, change the font size and others... How can i do it??. I don't know how... I use this Class:

/*
 * Copyright (C) 2009 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.edec.aptr;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.UUID;

import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothServerSocket;
import android.bluetooth.BluetoothSocket;
import android.content.Context;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.Log;

/**
 * This class does all the work for setting up and managing Bluetooth
 * connections with other devices. It has a thread that listens for incoming
 * connections, a thread for connecting with a device, and a thread for
 * performing data transmissions when connected.
 */
public class BluetoothService {
    // Debugging
    private static final String TAG = "BluetoothService";
    private static final boolean D = true;

    // Name for the SDP record when creating server socket
    private static final String NAME = "BTPrinter";

    // Unique UUID f