Hi. It depends upon the printer type. If it is dot matrix (the type that uses an ink ribbon), it usually means the flexi cable has partially broken, so power to the head is not continuous as it moves back and forth. If it is a thermal printer (no ribbon and uses thermal paper) then it can mean that some of the tiny elements in the head have failed and the head or whole printer will need replacing. Without seeing it further I can't give much more info. either way, it is almost certainly a dealer repair job.
-----------------------------------------
For Sam4s and Samsung programming / owners / service manuals:
http://the-checkout-tech.com/manuals2/cashregisters/samsung1.php
Mark, February 2010
