HP 2000CP 2500CP - Manual (Page 155)

Print Quality 6-13 HP DesignJet CP Series Printers
Test Pattern 3: Nozzle Print Test
Use this test purely to confirm an error highlighted in Test Pattern 2.
Some of the printhead nozzle problems that you will see in Test Pattern
3 do not mean you will not get perfect image quality results. The printer
has internal corrections that will hide many nozzle defects.
In this test all the 240 nozzles of each printhead are tested. For each of the
4 colors you will see the numbers 10 thru to 240 over the diagonally stepped
lines in increments of 10. These numbers correspond to the nozzle number
that prints each step.
There are two printhead nozzle errors:
D Nozzles not printing.
D Nozzles misdirected.
Nozzles not printing
There are two ways to see this problem, it is easier to see the error from the
first check.
1 In the top pattern, marked with numbers, if the diagonally stepped lines
are broken in one or more steps it indicates that this specific nozzle(s)
may be blocked and are not printing. White lines will also be visible in
the area fill at both sides of the pattern.
2 Below the top pattern, there is a set of horizontal straight lines. When one
or more nozzles are not printing the corresponding lines will be missing.
Nozzles misdirected
If all the stepped lines are visible in the top pattern, then all the printhead
nozzles are printing. However the nozzles could still be misdirected, possibly
due to some dried ink around the nozzles.
There are two ways to see this problem, it is easier to see the misalignment
from the second check.
3 In the top pattern, marked with numbers, if the diagonally stepped lines
are not equally positioned in every step it indicates that this specific
nozzle(s) may be misdirected.
4 Below the numbered pattern, there is a set of horizontal straight lines.
When one or more nozzles are misdirected there will be unequal spaces
between the corresponding lines.