Datamax Prodigy Plus Operator's Manual page 127

The second of the two test labels is the Test Pattern Label. This label is
used to determine whether the Printhead is in need of replacement.
'Good' and 'Bad" test pattern labels are shown in Figure 3-5.
Prodigy Max Operator's Manual
Figure 3-5 Printhead Test Label
Good test label indicates
Printhead is operating
normally.
Streaks in test label indicate a
dirty or faulty Printhead.
(See Chapter 3 for cleaning
and replacement).
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