HP Latex 700 Graininess in solid coloured areas

I keep on getting an unusual amount of graininess, specially visible in solid coloured areas. This keeps on happening and it usually gets better by itself after a week or so which is very strange . I'm guessing it is a tension issue (or a combination of tension+ printhead issues) but I'm not able to find a permanent solution. Lines look more sharp when they are horizontal, vertical lines look more blur. There is no banding.

Here is the things I already tried:

• Unloaded and loaded the material (wallpaper)
• Substrate advance calibration
• Cleaned OMAS sensor
• Printhead cleaning
• Printhead Status plot looks ok (printheads do not seem clogged)
• Maintenance cartridge is new
• Manual PH alignment
• Lowering the curing temperature to 75º
• Input/Output tension and vacuum settings seems to be ok

Does anybody have any recommendations of what should I try next to fix this issue?

Thanks in advance!

I'd recommend checking your printheads as well as your ink cartridges to make sure they're not being overused. For example, printheads are recommended to be changed around 3000-4000 ml of use. You should also check on the optimizer settings for your color profile and adjust them to see if that helps.

Hi @alba22429,

From what has been explained we can point to 3 variables: alignment, media control, or wrinkles in the Pz.

Alignment Pen to pen: By commenting that the horizontal lines printed are OK and the ones that look wrong are the vertical ones, we rule out a feed problem. Printing an HP Control Print you can filter if there is an advance or alignment problem by checking the reference points of the plot. If it is an alignment failure, it will be possible to see which color is not aligned. If after a manual alignment, it is not OK, replace the suspect PH.

Media control: It could also be a matter of rotation of the media during printing (the grain areas that you mention are oscillating from L to R on the media). In this case we recommend the following:

• Have the printer updated with the latest FW.

• Make sure to use the corresponding OMS, in case you don't have it, use the generic Wallpaper profile.

• Activate the "Optimize for tiling" option during the loading process.

• Reduce the skew threshold to 1 mm during the loading process.

• Printing with TUR.

Media deformity: Another option, from the comment that the grain is especially visible in the solid color areas, can also point to a problem with media deformation in the Pz due to ink loading. Try printing with a print mode with less Ink Density or generate one with less. This will help to have better control of the media.

If after all these the problem continues, please contact your support representative.