HP Designjet T920 ePrinter series - Manual (Page 180)

1. Use the same paper type that you were using when you detected a problem.
2. Check that the selected paper type is the same as the paper type loaded into the printer. See View
information about the paper on page 56 .
3. At the printer's front panel, press , then , then select Image Quality Maintenance > Print
diagnostic image.
It takes about two minutes to print the Image Diagnostics Print.
The print is divided into two parts, both of which test printhead performance.
● Part 1 (top) consists of rectangles of pure colors, one for each ink. This part represents the print quality
that you will get from each color.
● Part 2 (bottom) consists of small dashes, one for each printhead nozzle. This part complements the
first, and aims more specifically to detect how many faulty nozzles each printhead has.
Please look carefully at the print. The names of the colors are shown above the rectangles and to the left of
the patterns of dashes.
First look at the upper part of the print (part 1). Each colored rectangle should be a uniform color without any
horizontal lines across it.
Then look at the bottom part of the print (part 2). For each individual colored pattern, check that most of the
dashes are present.
If you see horizontal lines in part 1 and also missing dashes in part 2 for the same color, you should clean the
printhead, selecting the relevant color group. However, if the rectangles look solid, do not worry about just a
few missing dashes in part 2; these are acceptable because the printer can compensate for a few clogged
nozzles.
Here is an example of a gray printhead in a good state:
172 Chapter 18 Troubleshooting print-quality issues ENWW