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