The SAM4s SPS-520 models which consist of the 520R and 530F can interface to several different external printers The most common maybe a kitchen printer for the 520F model or the bar code printer for the 520R.
The SAM4s SPS-520 features two printers. One printer for the receipt and the second printer for the journal or audit printer. If you are looking for replacement printer for any of those you can find them here. SAM4s SPS-520F parts or the raised keyboard model here SAM4s SPS-520R replacement parts