Printing right after each invoiced item on P.O.S.

Thank you sir. However, I have developed one that is already operating in my store which is probably just the same as your POS. I wish change that and print right at the moment the item is entered which is also the moment it has already passed the cashier and bagged by the bagger. In groceries where there are many customers and many items being invoiced it is advantageous to print simultaneously everytime an item is scanned (which is also just proper to be saved as line transaction).