{HEAD ~ a printing unit} that receives print data from the host computers connected by said control unit, and carries out {TAIL ~ printing processing} based on the received print data, 
{ HEAD ~ a printing unit } that receives print data from the host computers connected by said control unit , and carries out { TAIL ~ printing processing } based on the received print data ,
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH