Re: Wavy lines at start of the print

I am getting funny wavy lines at the start of the print. I'm using self adheavsive vinyl. An anyone suggest what the cause of these are?

It only happens for the first meter of print.

Hi MrPrintproblem,

I will really need more information in order to make a proper guess. Would you please indicate me the printer model, media and RIP.

Thank you in advance.

Hello,

I am using a HP L25500 on self adhesive gloss vinyal and using Flexisign and production manager.

Its a bit strange that they only appera for the first meter or so of print then dissappear.

regards

Have you any ideas??

?

Hi Mr.Printproblem,

It looks to me like a plasticizer issue. Plasticizer shows up as randomly non-uniform areas with “coalescence like” graininess and increases the visibility of pinchwheel marks. Find below some recommendations:

• The only way to remove plasticizer is to “wash it out” with isopropyl alcohol. This is not practical for printing but can be used as a diagnostic tool: by washing only part of the substrate the defects can be made appear (not washed areas) and disappear (washed areas).
• Change printing material or, at least, the production batch of the material used (preferred the ones that have not been stored for a long time).
• In some cases, increasing heater temperature and number of passes can reduce the effect.

Hope this recommendations will help.

Thanks. I have changed a few of the parameters with looks like it has improved the print quality. The issue I have now is the colours on the print look very washed out. The colours before look very vibrant in comparison. Any ideas on this one??

Hi MrPrintproblem,

In order to make a proper guess, we need to know wich parameters did you changed?

Looking forward to hear from you

Thanks.

I reduced the vacuum. I'm using LD2740G gloss vinyl. Do you happen to know the best parameters/ profile for this media type?

Hi Printproblem,

I've looked for your media in the HP Media Solutions Locator, and I've been not able to find it. I've also asked to several operators here, and they've never use it. I can only recommend you to use the generic SAV profile and tune it until you get optimal results.

Also, I'll recommend you to check if you are having plasticizers issues with it, in that case I will strongly recommend you to use another media. Let me know if you want any advise.

Hope this helps.

Hi, I realize this is an old post now & not sure if you ever resolved the problem, but I think I may be able to help as I too have what appears to be the same issue & have recently discovered that it appears to be very small amounts of oil getting onto the pinch wheel rollers that sit on top of the material as it enters the print platen.

It ties up with the fact that it only appears for about a metre or so & as the print continues it dries up. Then next time you start the printer up again it will have built up to a level that transfers onto the pinch wheel again & you get the same issue on the first metre or so again.

It seems to be coming from in-between the white slightly translucent plastic of the pichwheel assembly & the metal sub-assembly. If you push down firmly on the white plastic just behind the pinch wheels you may see a very small amount of oil squidge between the two layers.

I can only presume that this is coming from excess oil applied to the printhead guide rail. possibly if the felt pads are fully soaked & not able to "mop up" any excess.

I am currently attempting to use lint free tissue carefully between the layers to wick the oil out.

Any luck with this issue? I am having the same challenge. Replaced most print heads that were out of warranty. The issue seemed to happen right when I replaced the optimizer cartridge 2 weeks ago. The issue has persisted across multiple rolls of both HP Prime Air Gloss Vinyl and Brightlines Vinyl. The issue doesn't seem to occur on areas with heavy ink load, but lighter areas especially blues and pinks.

I have not had to call in a tech in 4 years of ownership, but I am at the end of my rope and can't have our business shut down due to this issue.