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Print Quality
HP Designjet 4000/4020 Printer Series Service Manual
Nozzle Print Test
The Nozzle Print Test is part of the Image Quality Service Plot. This can
only be printed through the Service Utility Menu. This test is designed to
check if the printhead nozzles print correctly. The test prints out every single
nozzle of each Printhead. No error hiding or Printhead Alignment algorithm
is applied. For each Printhead, you can see both the adjacent and the
consecutive nozzles.
This is what you would see if there are nozzles not printing correctly:
1 On the right of each Printhead Nozzle test, there is a series of numbered
stepped diagonal lines. If one or more of the nozzles are malfunctioning or
mis-positioned, you will see that the stepped lines are broken or misdirected
in one or more places.
2 On the left of each Printhead Nozzle test, there is a series of horizontal
straight lines. If one or more nozzles are misdirected there will be unequal
spaces between the corresponding lines.
How to fix the Nozzle Defects
If the printer has nozzle defects, it does not mean that you will
not get perfect print quality results. The printer has automatic
procedures to hide many nozzle defects.
1 Recover the printheads using the option through the Front Panel (Ink Menu/
Printheads/Recover Printheads).
2 Reprint the Nozzle Print test to check that the defective nozzles have been
corrected.
3 If the problem continues, replace the faulty Printhead.
Printhead No.8 Printhead No.6
Printhead No.2Printhead No.4
Printhead No.7 Printhead No.5
Printhead No.1Printhead No.3
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