Thermal Printer Arduino

#include "Adafruit_Thermal.h"
#include "SoftwareSerial.h"
SoftwareSerial mySerial(10, 11);
Adafruit_Thermal printer(&mySerial);

void setup() {
  mySerial.begin(9600);
  printer.begin();
  printer.justify('C');
  printer.setSize('L');
  printer.println("Tes Thermal\n");
  printer.setSize('S');
  printer.println("KelasRobot.com\n\n\n");
  printer.sleep();
  delay(3000L);
  printer.wake();
  printer.setDefault();
}

void loop() {

}