Trouble with loop (arduino) - c

Question

I am trying to create a small stall at school using and arduino,
the project is to scan items using a barcode scanner enter the price and issue a receipt. the barcode scanner is connected to serial port and keypad and printer are connected via software serial. I am using a 3.5" tv as the display. the items can be identified by the first 3 digits of the barcode. I want to include the item names somewhere in the sketch and match and print them when the string starts with their number.
I have created a sketch with a lot of help from other forum users but the date is being repeatedly printed and not much else is happening. How do I make the date print only once. and also how do I buffer data from serial and software serial before printing.
//#include <TVout.h>
//#include <video_gen.h>
//ARDUINO 1.0 COMPATIBLE ONLY!
//ARDUINO 1.0 COMPATIBLE ONLY!
#include <Time.h>
#include <DS1307RTC.h>
#include <SoftwareSerial.h>
//#include <LiquidCrystal.h>
#include <Thermal.h>
#include <Wire.h>
//TVout TV;
int printer_RX_Pin = 3;
int printer_TX_Pin = 4;
int incomingByte = 0;
Thermal printer(printer_RX_Pin, printer_TX_Pin, 19200);
String readString; // a string to hold incoming data
//SoftwareSerial mySerial(10, 11);
void setup(){
//TV.begin(PAL,120,96);
// TV.select_font(font6x8);
Serial.begin(9600);
//mySerial.begin(9600);
setSyncProvider(RTC.get);
// if (timeStatus() != timeSet )
// Serial.println("Unable to sync with the RTC");
// else
// Serial.println("RTC has set the system time");
//tv.print(scan item) ???
//ITEM SCANNED GETS STORED INTO string.Readstring
//tv print (enter donation Amount)
//INPUT FROM KEYPAD GETS STORED INTO BUFFER1 (KEYPAD IS HOOKED UP TO SOFTWARE SERIAL PINS)
//THEN PRINTER PRINTS TITLE (MAYBE BETTER TO WAIT FOR ALL INPUT BEFORE PRINTING)
printer.justify('C');
//sets text justification (right, left, center) accepts 'L', 'C', 'R'
printer.setSize('L'); // set type size, accepts 'S', 'M', 'L'
printer.println("School Feast "); //print line
printer.setSize('M'); // set type size, accepts 'S', 'M', 'L'
printer.println("My Stall"); //print line
printer.println("My Town");
printer.feed(); //advance one line
printer.println(" My Country");
printer.feed(); //advance one line
}
void serialRead() {
while (Serial.available()) {
delay(10);
if (Serial.available() >0) {
char c = Serial.read();
readString += c;};
}
}
void loop() {
// THEN TIME GETS PRINTED
tmElements_t tm;
if (RTC.read(tm)) {
Serial.print(" ");
print2digits(tm.Hour);
Serial.write(':');
print2digits(tm.Minute);
Serial.write(':');
print2digits(tm.Second);
Serial.print(" ");
Serial.print(tm.Day);
Serial.write('/');
Serial.print(tm.Month);
Serial.write('/');
Serial.print(tmYearToCalendar(tm.Year));
Serial.println();
printer.print(" ");
print2digits(tm.Hour);
printer.write(':');
print2digits(tm.Minute);
printer.write(':');
print2digits(tm.Second);
printer.print(" ");
printer.print(tm.Day);
printer.write('/');
printer.print(tm.Month);
printer.write('/');
printer.print(tmYearToCalendar(tm.Year));
printer.println();
} else {
if (RTC.chipPresent()) {
Serial.println("The DS1307 is stopped. Please run the SetTime");
Serial.println("example to initialize the time and begin running.");
Serial.println();
} else {
Serial.println("DS1307 read error! Please check the circuitry.");
Serial.println();
}
delay(9000);
}
delay(1000);
}
void print2digits(int number) {
if (number >= 0 && number < 10) {
Serial.write('0');
}
Serial.print(number);
if (Serial.available() > 0) {
readString = "";
serialRead();
String Item = readString.substring(0,3);
//THEN ITEM PRINT( IDENTIFY ITEM BY FIRST 3 CHARACTERS OF STRING, HOW??)
Serial.print(Item);
printer.print(Item);
Serial.println();{
//THEN PRINT DONATION AMOUNT(INPUT FROM SOFTWARE SERIAL)
//printer.print(software.serial buffer)
//printer. print("GBP");
//clear display
//tv.clear
}
}
}