The print head unit 1, wherein {HEAD ~ the parallelism adjusting means} comprises at least one piezoelectric motor and {TAIL ~ at least one capacitive sensor}, and the at least one piezoelectric motor is configured for actuating the first print head and the second print head by closing a loop with the at least one capacitive sensor 
comprises
The print head unit 1 , wherein { HEAD ~ the parallelism adjusting means } comprises at least one piezoelectric motor and { TAIL ~ at least one capacitive sensor } , and the at least one piezoelectric motor is configured for actuating the first print head and the second print head by closing a loop with the at least one capacitive sensor
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH