HP Designjet L25500 Printer Series - Maintenance and troubleshooting guide (second edition)

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Use a higher number of passes: you will probably see less grain with ten or more passes.
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Lower the ink quantity.
If the problem persists, call your service representative. See
When you need help on page 51.
Horizontal banding
Try the following remedies if your printed image suffers from added horizontal lines as shown (the color may
vary).
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If bands affect mostly dark or saturated colors, or only area fills near the edges of the substrate, the
cause could be insufficient drying of the ink. Try the following suggestions.
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Reduce the ink quantity.
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Increase the number of passes.
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If bands affect all colors across the width of the printed image, and you are using no more than six
passes, the cause is probably a substrate advance problem. Use the front panel to adjust the substrate
advance on the fly. If you have dark bands, increase the substrate advance; if you have light bands,
decrease it. When you find the right adjustment, store the value in the RIP for future prints on the same
substrate.
Another cause could be a fiber attached to one of the printheads. Remove the printheads one at a time
and remove any fibers that you see attached to them.
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If bands affect only some colors, the cause could be a defective printhead.
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Print the printhead status plot (see
Use the printhead status plot on page 22). If necessary, clean
the printheads (see
Clean (recover) the printheads on page 18). If the problem persists, clean them
again.
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If the problem persists, try aligning the printheads (see
Align the printheads on page 11). If
necessary, try aligning them manually.
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If the problem persists, print the printhead status plot again. Identify the printhead with the
greatest number of blocked nozzles, and replace it.
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If bands affect most of the colors, the printheads could be misaligned. This is likely if you have not
aligned the printheads for a long time, or if there has been a substrate jam. Align the printheads if
necessary (see
Align the printheads on page 11). You can check whether it is necessary by using the
printhead status plot (see
Use the printhead status plot on page 22).
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If banding occurs mostly in black areas, create a new color profile using pure black and not a mixture of
other colors. See your RIP documentation.
If the problem persists, call your service representative (see the User's guide).
26 Chapter 5 Troubleshoot print-quality issues ENWW