HP 4020 HP Designjet 4020 and 4520 Printer Series - User's Guide: English - Page 132

Diagnostics Here are three examples of a black rectangle in close-up, showing the fine lines of which it is made: In the first two examples above, there are so many missing lines that the printhead may be faulty. In the third case there are only a few missing lines, which are acceptable, because the printer can compensate for such minor problems. Corrective action If part 3 shows a problem with one printhead, but part 2 shows no problem, there is no immediate need to take any corrective action, because the printer is able to compensate for the problem and maintain print quality. However, if part 2 also shows a problem, continue as follows: 1. Clean the printheads. See Recover (clean) the printheads on page 97. 2. If there is no improvement in print quality, replace the printhead that shows the problem. See Remove a printhead on page 92 and Insert a printhead on page 94. If I still have a problem If the entire Image Diagnostics Print contains no defects and you still experience print quality problems, here are some things to check: ● Try using a higher print quality option. See Choose print quality settings on page 57 and Change the print quality on page 57. ● Check the driver you are using to print with. If it is a non-HP driver, download the correct HP driver from the Web: see Update my printer's software on page 116. ● If you are using a non-HP RIP, its settings may be incorrect. Refer to the documentation that came with the RIP. ● Check that your printer's firmware is up to date. See Update my printer's firmware on page 116. 122 Chapter 12 How do I... (Image Diagnostics Print topics) ENWW