HP Designjet 5000 Service Manual - Page 188

Print Quality NOTE Nozzle Print Test If your 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. This type of problem affects print quality mostly in Productivity and Max. Speed modes. The nozzle print test is number 5 in the Diagnostic Print. In this test the 512 nozzles that each Printhead uses to print with are tested. 5 Nozzle Test for Cyan Printhead Missing Squares Each nozzle on each Printhead prints a series of very close lines that can be seen as small squares in the Diagnostic Print. You can see whether a nozzle is not working if squares are missing or if a nozzle is malfunctioning, the color fill is less dense. If you have more than 30 defective nozzles, the Printer will automatically request you to recover the Printhead(s) ((XX20)RECOVER), or to replace the Printhead(s) ((XX21)REPLACE) if the defect cannot be recovered. This test also allows you to check the condition of the Printhead if your Printer displays a (xxxx)REPLACE or (XXXX)RECOVER message for a Printhead that has recently been changed or recovered successfully. If there are not a large number of squares missing, and so the nozzles are firing correctly, you may have a drop detector problem. 6-14 HP DesignJet 5000 Series Printers Service Manual