Lexmark 4227-X00 - Manual (Page 33)

2-10 Service Manual
4227-X00
Service Checks
Auto Gap Service Check
Theory of Operation:
The Auto Gap Motor and Gap Home Sensor automatically set the
printhead gap for the thickness of paper being used by rotating the
eccentric carrier shaft. The printer detects maximum gap with the
Gap Home Sensor, and minimum gap by driving the printhead
against the platen. In addition to compensating for the thickness of
the paper itself, the printer must increase the air gap for thicker
papers.
With Auto Gap On, the following occurs:
•
POST.
•
Auto Gap resets.
•
The printer unloads paper if it is loaded, to prepare to measure
the travel span.
•
The auto gap motor drives the printhead against the platen to
measure the total travel span.
•
Auto Gap resets again, to make room for paper to be loaded.
•
The paper feeds to the print line.
•
The auto gap motor drives the printhead against the paper to
measure the total travel span minus the paper thickness.
•
Auto Gap resets again.
•
The printhead moves to the appropriate gap position for the
installed paper.
•
The Ready LED turns on, the carrier centers, and the paper
moves to the tearoff position.