HP Designjet T790 1118 mm User Manual

Horizontal smears on the front of coated paper
If a lot of ink is used on plain or coated paper, the paper absorbs the ink quickly and expands. As the
printheads move over the paper, the printheads may come into contact with the paper and smear the
printed image. This problem is normally seen only on cut sheets of paper (not on roll paper).
Whenever you notice this problem, cancel the printing job immediately. Press  and also cancel the
job from your computer application. Soaked paper can damage the...

Edges of objects are stepped or not sharp
If edges of objects or lines appear to be poorly defined or lighter in density, and you have already set
the print-quality slider to Quality in the driver dialog, select the custom print-quality options, and try
setting the quality level to Normal. See 
Printing on page 52.
Edges of objects are darker than expected
If edges of objects seem darker than expected, and you have already set the print-quality slider to
Quality in the driver dialog, select the custom...

Vertical lines of different colors
If your print has vertical bands of different colors along it:
1.Try using thicker paper, choosing from the recommended paper types such as HP Heavyweight
Coated Paper and HP Super Heavyweight Paper. See 
Order paper on page 142.
2.Try using higher print-quality settings (see 
Printing on page 52). For instance, if you have set the
Print Quality slider to Speed, try setting it to Quality.
White spots on the print
You may notice white spots on the print. This is probably...

5.If the problem consists of color differences between your print and your monitor, please follow the
instructions in the “How to calibrate your monitor” section of the HP Color Center. At this point,
you may wish to reprint your job in case the problem has been solved.
6.Print the Image Diagnostics Print. See 
The Image Diagnostics Print on page 178.
7.Try using the color adjustment options to produce the colors you want. See 
Color adjustment
options on page 89.
If the problem persists despite all the...

The image is clipped
Clipping normally indicates a discrepancy between the actual printable area on the loaded paper and
the printable area as understood by your software. You can often identify this kind of problem before
printing by previewing your print (see 
Preview a print on page 61).
●Check the actual printable area for the paper size you have loaded.
printable area = paper size – margins
●Check what your software understands to be the printable area (which it may call printing area
or imageable...

Some objects are missing from the printed image
Large quantities of data may be necessary to print a high-quality large-format print job, and in some
specific workflows there may be issues that can lead to some objects missing from the output. Here are
some suggestions to help you to avoid this problem.
●Try using the PostScript printer driver to print your job, if you have not already tried it.
●Select a smaller page size and scale to the desired final page size in the driver or in the front
panel....

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 printhead. This part represents the
print quality that you will get from each color.
●Part 2 (bottom) consists of small dashes, one for each nozzle on each printhead. 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...

And here is an example of the same printhead in a bad state:
Corrective action
1.Clean any faulty printheads (see Clean the printheads on page 184). Then reprint the Image
Diagnostics Print to see whether the problem has been solved.
2.If the problem remains, clean the printheads again, and reprint the Image Diagnostics Print to see
whether the problem has been solved.
3.If the problem remains, consider cleaning your printheads manually (see 
Clean the printheads
on page 184). You could also try...

If you still have a problem
If you still experience print-quality problems after applying the advice in this chapter, here are some
further things that you can do:
●Try using a higher print-quality option. See 
Printing on page 52.
●Check the driver you are using to print with. If it is a non-HP driver, consult the driver vendor about
the problem. You could also try using the correct HP driver, if feasible. The latest HP drivers can
be downloaded from 
http://www.hp.com/go/T790/drivers or...

18 Troubleshooting ink cartridge and
printhead issues
●Cannot insert an ink cartridge
●
Ink cartridge status messages
●
Cannot insert a printhead
●
The front-panel display recommends reseating or replacing a printhead
●
Clean the printheads
●
Clean the printhead drop detector
●
Align the printheads
●
Printhead status messages
182 Chapter 18   Troubleshooting ink cartridge and printhead issues ENWW