HP Latex 3000

To check printhead alignment, print the printhead alignment diagnostics plot (see Printhead alignment
diagnostics plot on page 101). As a general rule, the biggest contributors to grain caused by printhead
alignment are (in this order):
◦
Bidirectional alignment
◦
Intra-color alignment (alignment between the two printheads of the same color)
◦
Inter-color alignment (alignment between different colors)
Here are some tips for solving this problem:
◦
If the printhead alignment was done with a different substrate of different thickness, probably a
new printhead alignment is needed.
◦
If the problem comes from an automatic printhead alignment, you can try manual alignment for
better control of the alignment process.
◦
If the problem comes from a manual alignment, fine-tune it by identifiying the offenders in the
printhead alignment diagnostics plot. See
Manual alignment on page 98.
●
Printhead-to-ribs spacing. Check the printhead-to-ribs spacing in the Internal Print Server. If it is
higher than normal, try reducing it.
●
Spit on page. This is an algorithm that randomly fires ink onto the substrate when a printhead has not
been used for a while. In general, the dots are hardly visible, but it may be possible to detect them on
some substrates with high dot gain, especially in white areas of the print. You can reduce the effect by
reducing the number of passes.
●
Substrate wrinkles. If you see patches of high grain in some local areas of the print, this could be
caused by wrinkles in the substrate. See
There are wrinkles and ink smears on the substrate
on page 224.
●
Color usage. In general, 4-color printing produces more grain than 6-color printing.
Physical deformation marks
You may occasionally see physical deformation of the substrate. This issue is not a mispositioning of the
dots, but a physical deformation of the substrate that usually occurs after the dots have been printed. There
are various kinds of deformation that may occur:
●
Perforated plate marks. The print suffers from an added matte pattern over the areas with more ink
density. You can see small circles scattered over the picture with different levels of gloss.
Here are some tips for solving this problem:
◦
Increase the curing temperature.
◦
Increase the curing airflow.
ENWW Advanced print-quality troubleshooting 247