HP Designjet 4520 Printer series - Manual (Page 129)

If you have horizontal misalignment, you will see something like this:
If you have vertical misalignment, you will see something like this:
If you have bidirectional misalignment, you will see something like this:
Corrective action
1. Align the printheads, using the same paper type with which you were experiencing unacceptable
print quality, if feasible (some paper types are not suitable for printhead alignment). See
Align the
printheads on page 101 .
2. If there is no improvement in print quality, contact your customer service representative.
Interpret Image Diagnostics part 2
The purpose of part 2 is to test whether the printheads and the paper advance mechanism are working
correctly. This part of the print should not be used to check for color consistency or accuracy.
ENWW Interpret Image Diagnostics part 2 119
Diagnostics