Lexmark 4I3 - Manual (Page 207)

The printer also prints a single line of H’s.
4. If the H’s do not start where you want your left margin, press
Scroll or Scroll until the printer displays the desired value
for the left margin position. For each change in value, the left
margin is changed 0.686 mm (0.027 in.).
5. Press Enter.
An asterisk ( * ) appears in front of the selected value. The forms
advance one line and the row of H’s prints again. This value is
now the current left margin position.
6. Repeat Steps 4 and 5 until the left margin is correctly aligned.
(You can press Line Feed or Form Feed [Load/Eject for F3 or
F4 forms devices] to move the forms between printing the rows
of H’s.)
Chapter 5. Tests 5-7