HP Designjet T790 1118 mm User Manual

							4.Select the percentage of change from –100% to +100%. To correct light banding, decrease the
percentage.
To correct dark banding, increase the percentage.
5.Press OK on the front panel, to save the value.
6.Wait until the front panel displays the status screen and reprint your print.
Return to default calibration
Returning to the default calibration sets all the corrections made by the paper advance calibration to
zero. To return to the default paper advance calibration value, you must reset the calibration.
1.
From the front panel, press 
, then , then Image Quality Maintenance > Paper
advance calibration > Reset paper advance.
2.Wait until the front panel displays the operation has completed successfully.
ENWWRecalibrate the paper advance
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							17 Troubleshooting print-quality issues
●General advice
●
Print quality troubleshooting wizard
●
Horizontal lines across the image (banding)
●
Lines are too thick, too thin or missing
●
Lines appear stepped or jagged
●
Lines print double or in the wrong colors
●
Lines are discontinuous
●
Lines are blurred
●
Line lengths are inaccurate
●
The whole image is blurry or grainy
●
The paper is not flat
●
The print is scuffed or scratched
●
Ink marks on the paper
●
Black ink comes off when you touch the print
●
Edges of objects are stepped or not sharp
●
Edges of objects are darker than expected
●
Horizontal lines at the end of a cut sheet print
●
Vertical lines of different colors
●
White spots on the print
●
Colors are inaccurate
●
Colors are fading
●
The image is incomplete (clipped at the bottom)
●
The image is clipped
●
Some objects are missing from the printed image
●
A PDF file is clipped or objects are missing
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							●The Image Diagnostics Print
●
If you still have a problem
ENWW165
 
						

							General advice
When you have any print-quality problem:
●To achieve the best performance from your printer, use only genuine manufacturers supplies and
accessories, whose reliability and performance have been thoroughly tested to give trouble-free
performance and best-quality prints. For details of recommended papers, see 
Order paper
on page 142.
●Make sure that the paper type selected in the front panel is the same as the paper type loaded
into the printer (see 
View information about the paper on page 46). At the same time, check that
the paper type has been calibrated. Also make sure that the paper type selected in your software
is the same as the paper type loaded into the printer.
CAUTION:If you have the wrong paper type selected, you could experience poor print quality
and incorrect colors, and perhaps even damage to the printheads.
●Check that you are using the most appropriate print-quality settings for your purposes (see Printing
on page 52). You are likely to see lower print quality if you have moved the print-quality slider to
the Speed end of the scale, or set the custom quality level to Fast.
●Check that your environmental conditions (temperature, humidity) are in the recommended range.
See 
Environmental specifications on page 208.
●Check that your ink cartridges and printheads have not passed their expiration dates: see
Maintain the ink cartridges on page 137.
Print quality troubleshooting wizard
The Print Quality Troubleshooting Wizard can help with the following problems:
●Horizontal lines across the image (banding)
●The whole image is blurry or grainy
●Lines are too thick, too thin or missing
●Colors are inaccurate
To start the wizard:
●From the HP Utility for Windows: go to the Support tab, and select Print quality
troubleshooting.
●From the HP Utility for Mac OS: select Print quality troubleshooting in the Support
group.
●From the Mac OS Print dialog: go to the Services panel, select Device Maintenance,
then select Print quality troubleshooting from the list of maintenance tasks.
●From the Embedded Web Server: go to the Support tab, select Troubleshooting, then
select Print quality troubleshooting.
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							Alternatively, or if you have other print quality problems, you can continue reading this chapter.
Horizontal lines across the image (banding)
If your printed image suffers from added horizontal lines as shown (the color may vary):
1.Check that the paper type you have loaded corresponds to the paper type selected in the front
panel and in your software. See 
View information about the paper on page 46.
2.Check that you are using appropriate print-quality settings for your purposes (see 
Printing
on page 52). In some cases, you can overcome a print-quality problem merely by selecting a
higher print-quality level. For instance, if you have set the Print Quality slider to Speed, try setting
it to Quality. If you change the print-quality settings, you may wish to reprint your job at this
point in case the problem has been solved.
3.Print the Image Diagnostics Print. See 
The Image Diagnostics Print on page 178.
4.
If the printheads are working correctly, go to the front panel and press 
 and then  to see
the paper advance calibration status. If the status is DEFAULT, try performing paper advance
calibration: see 
Recalibrate the paper advance on page 161.
If the problem persists despite all the above actions, contact your customer service representative for
further support.
ENWWHorizontal lines across the image (banding)
167
 
						

							Lines are too thick, too thin or missing
1.Check that the paper type you have loaded corresponds to the paper type selected in the front
panel and in your software. See 
View information about the paper on page 46.
2.Check that you are using appropriate print-quality settings for your purposes (see 
Printing
on page 52). Select the custom print-quality options in the driver dialog, and try turning on the
Maximum detail option (if available). You may wish to reprint your job at this point in case the
problem has been solved.
3.If the resolution of your image is greater than the printing resolution, you may notice a loss of line
quality. If you are using the PCL or the HP-GL/2 and HP RTL driver for Windows, you can find the
Max. Application Resolution option in the driver dialogs Advanced tab, under
Document Options > Printer Features. If you change this option, you may wish to reprint
your job at this point in case the problem has been solved.
4.If lines are too thin or missing, print the Image Diagnostics Print. See 
The Image Diagnostics Print
on page 178.
5.
If the problem remains, go to the front panel and press 
 and then  to see the printhead
alignment status. If the status is PENDING, you should align the printheads. See 
Align the
printheads on page 186. After alignment, you may wish to reprint your job in case the problem
has been solved.
6.
Go to the front panel and press 
 and then  to see the paper advance calibration status.
If the status is DEFAULT, you should perform paper advance calibration: see 
Recalibrate the paper
advance on page 161.
If the problem persists despite all the above actions, contact your customer service representative for
further support.
Lines appear stepped or jagged
If lines in your image appear stepped or jagged when printed:
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							1.The problem may be inherent in the image. Try to improve the image with the application you are
using to edit it.
2.Check that you are using appropriate print-quality settings. See 
Printing on page 52.
3.Select the custom print-quality options in the driver dialog, and turn on the Maximum detail
option (if available).
Lines print double or in the wrong colors
This problem can have various visible symptoms:
●Colored lines are printed double, in different colors.
●The borders of colored blocks are wrongly colored.
To correct this kind of problem:
1.Reseat the printheads by removing them and then reinserting them. See 
Remove a printhead
on page 129 and Insert a printhead on page 132.
2.Align the printheads. See 
Align the printheads on page 186.
Lines are discontinuous
If your lines are broken in the following way:
ENWWLines print double or in the wrong colors
169
 
						

							1.Check that you are using appropriate print-quality settings. See Printing on page 52.
2.Reseat the printheads by removing them and then reinserting them. See 
Remove a printhead
on page 129 and Insert a printhead on page 132.
3.Align the printheads. See 
Align the printheads on page 186.
Lines are blurred
Humidity can cause ink to soak into the paper, making the lines blurred and fuzzy. Try the following:
1.Check that your environmental conditions (temperature, humidity) are suitable for high-quality
printing. See 
Environmental specifications on page 208.
2.Check that the paper type selected in the front panel is the same as the paper type you are using.
See 
View information about the paper on page 46.
3.Try changing to a heavier paper type, such as HP Heavyweight Coated Paper or HP Super
Heavyweight Plus Matte Paper.
4.Select a paper type that is slightly thinner than the paper you have loaded; this will persuade the
printer to use less ink. Here are some example paper types in ascending order of thickness: Plain
Paper, Coated Paper, Heavyweight Coated Paper, Super Heavyweight Plus Matte Paper.
5.If you are using glossy paper, try changing to a different type of glossy paper.
6.Align the printheads. See 
Align the printheads on page 186.
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							Line lengths are inaccurate
If you have measured your printed lines and find that the lengths are not sufficiently accurate for your
purposes, you can try to improve line length accuracy in the following ways.
1.Print on HP Matte Film, for which your printers line length accuracy is specified. See 
Functional
specifications on page 206.
Polyester film is about ten times more dimensionally stable than paper. However, using film that is
thinner or thicker than HP Matte Film will reduce line length accuracy.
2.Set the Print Quality slider to Quality.
3.Maintain the room at a steady temperature between 10 and 30°C (50 and 86°F).
4.Load the roll of film and let it rest for five minutes before printing.
5.If you are still not satisfied, try recalibrating the paper advance. See 
Recalibrate the paper
advance on page 161.
The whole image is blurry or grainy
1.Check that the paper type you have loaded corresponds to the paper type selected in the front
panel and in your software. See 
View information about the paper on page 46.
2.Check that you are printing on the correct side of the paper.
3.Check that you are using appropriate print-quality settings (see 
Printing on page 52). In some
cases, you can overcome a print-quality problem merely by selecting a higher print-quality level.
For instance, if you have set the Print Quality slider to Speed, try setting it to Quality. If you
change the print-quality settings, you may wish to reprint your job at this point in case the problem
has been solved.
4.
Go to the front panel and press 
 and then  to see the printhead alignment status. If the
status is PENDING, you should align the printheads. See 
Align the printheads on page 186. After
alignment, you may wish to reprint your job in case the problem has been solved.
5.
Go to the front panel and press 
 and then  to see the paper advance calibration status.
If the status is DEFAULT, you should perform paper advance calibration: see 
Recalibrate the paper
advance on page 161.
If the problem persists despite all the above actions, contact your customer service representative for
further support.
ENWWLine lengths are inaccurate
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							The paper is not flat
If the paper does not lie flat when it comes out of the printer, but has shallow waves in it, you are likely
to see defects in the printed image, such as vertical stripes. This can happen when you use thin paper
that becomes saturated with ink.
1.Check that the paper type you have loaded corresponds to the paper type selected in the front
panel and in your software. See 
View information about the paper on page 46.
2.Try changing to a thicker paper type, such as HP Heavyweight Coated Paper or HP Super
Heavyweight Plus Matte Paper.
3.Select a paper type that is slightly thinner than the paper you have loaded; this will persuade the
printer to use less ink. Here are some example paper types in ascending order of thickness: Plain
Paper, Coated Paper, Heavyweight Coated Paper, Super Heavyweight Plus Matte Paper.
The print is scuffed or scratched
The black ink pigment can be scuffed or scratched when touched by a finger, a pen or some other
object. This is particularly noticeable on coated paper.
Glossy paper may be extremely sensitive to the basket or to anything else that it contacts soon after
printing, depending on the amount of ink used and the environmental conditions at the time of printing.
To reduce the risk of scuffs and scratches:
●Handle prints carefully.
●Avoid stacking prints on top of each other.
●Catch your prints as they are cut from the roll and do not let them fall into the basket. Alternatively,
leave a sheet of paper in the basket so that freshly printed sheets do not make direct contact with
the basket.
Ink marks on the paper
This problem can occur for several different reasons.
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