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Backlite Banding....

#1 Simon_Mediatech 4 years ago

Hello Tim,

Here’s my situation:

2 printers, same problem: Latex 260

Product: Intelicoat SBL7

Profil: HP Premium Vivid Color Backlite Film in 10 pass Unidirectional (Uni is use for proper drying)

Rip: Onyx 11 and 10

Printheads: all new on the first printer and used ones on the second printer.

We have banding that come and go. This problem always show up all deep black areas.

When we send the prints, the first one is ok then after one or two it begins to do what’s in the pictures. Even on the fotoba cutting marks.

If you have any idea it would be welcome.

Thank You

Simon

#2 HP-TimothyM 4 years ago

Hi, Simon, thanks for posting. I appreciate the direct callout, very kind, but please feel free to ask the room, we have many experts here that can help you.

OK, first, I would use the Intellicoat SBL-7 profile that's on the HP Media Locator instead of the HP one you are using (attached screenshot). I run my backlits at 16pass or 20 pass. Yes, I know it's a tad slow, but backlit is all about quality, and quality is better a little slower. It allows you to add more ink, for better saturation, especially in rich blacks. Another couple I like is the Natura BF600 and the Neschen Printlux, but I run both slow. I run my backlits BiDi, in fact, I run almost everything BiDi on the 260.

Next, that looks wrong in any mode, that black is shotgunning all over the place and I'm not sure why. It almost looks like you have something dragging over the heads. Do a good cleaning, remove the black heads and inspect them for any obvious imperfection, also clean your contacts (refer to manual on this for instructions).

It could be the coating, as one possibility (run another Media Locator backlit and see if the issuet tracks across both media brands) because you say it is happening in both machines. Do both machines really print like that? I need to see pics from both machines if you can.

I have had many 260's and all run backlit and none have ever printed that, so it is definately irregular.

Try this for now:

Clean the heads from the front panel, reseat them, clean the contacts, and then do a full printhead alignment (you can use the polyester backlit film, it is very stable)

Run the Intelicoat profile I suggest at 16pass and see what they look like on each machine.

See if you can get a sample roll of another backlit brand, Sihl, HP, Natura, and Neschen are all good and check it it does the same thing on another media.

Does this happen on paper and SAV as well or only the backlit?

Take a flashlight and look carefully at the underside of the carriage; you are looking for anything that might be dragging from the carriage and causing this.

I'll check back in a day or two. Do you have a timeframe on this, a deadline or a time commitment? Also, are you in the US and who would be your reseller?

All the Best,

Timothy

Attachments
#3 HP-TimothyM 4 years ago

Simon, anything you send, like pics of the problem, please do so on each machine and note on the pic with what machine it was run.

I really want to use the fact that you have 2 identical printers to help isolate the issue. If the issue is identical with both machines, then it points to media or software or environment, generally. It's fairly uncommon to have both machines going haywire in exactly the same way, at the same time, mechanically.

I want to see if there are similarities and/or differences between each machine running the same file with the same print preset.

And let's get your reseller involved; I want them in on this conversation and on the solution.

Best,

Timothy

#4 Simon_Mediatech 4 years ago

Good Morning Tim,

In fact I'm the reseller working with Mediatech in Montreal. I've been in Alpharette twice.

I will post pics of both printers later today.

We've tried the SBL7 profil without any problem but the client doesn't like the result with that profil. The colors are off.

So I guess that in 10 passes with a profil that have high ink limit checked the print heads have problem to fire that amount of ink at that speed. We only see that problem in deep black visual.

We will try to print in 16 pass BiDi to see if the problem resolve itself.

Thank you for your fast input.

Simon

#5 HP-TimothyM 4 years ago

Glad to help, Simon. Please keep in mind that that a preset (a profile is a small part of the preset) also includes specific ink levels for a given speed at a given temperature. So when the HP profile was made, it was made for that film at that speed at that temp; the characteristics of the SBL-7 may be different and have a different thermal deformation point and different coatings. They may or may not be compatible. Feel free to try some of the other presets on the HP Locator and see if that color works a bit better--or use the HP in a higher pass mode.

The over-spray looks to be another issue altogether, unless so much ink is going down that the media cannot handle it, which I doubt. Send me some pics of the issue on each machine.

But do the cleaning, etc I recommended first.

T

#6 Simon_Mediatech 4 years ago

Here's the pics of both printer results:

We did the cleaning and the printhead alignment. We still have the problem.

We are still making tests. The job is for the end of next week.

The SBL7 profil in 16 pass BiDi seems to work ok. Now we are testing if it's completly dry beacause we had issue in the past with backlite not truly dry, it was making ''fog'' in the lightbox.

I will have more info monday

Have a good weekend

Simon

#7 HP-TimothyM 4 years ago

Fog in the lightbox is not unusual for backlit, especially with heavy black. It condensation, mostly. I have not had an SBL-7 with the HP MSL profile not be dry. Still no idea why you have that overspray. And on both machines. Leads me to think that coating is bad on the media.

Can you get some other backlit material?

Does it do this on frontlit, like SAV or paper?

T

#8 Simon_Mediatech 4 years ago

Sorry for the late follow-up.

We will try an other backlite material as soon as the job is delivered. I will try on the HP backlite and the Natura

We were able to print the job with the SBL7 16 pass profil without any problem.

So I guess 10 pass was a bit to much ink to deliver by the printheads.

Good weekend

Simon

#9 Simon_Mediatech 4 years ago

Update!

The probleme came back. Last time the profil in 16pass bidir solved the problem but it came back.

We finally found the real solution... just activate the extra cleaning in the image quality menu.

Regard

Simon

The opinions expressed above are the personal opinions of the authors, not of HP.

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