Mid Page printing issues. OMAS??

[BIG EASY DOES IT]

We have a latex L360 print on reflective all the time. We are having some new random issues. Wondering if anyone else has had similar issues and if you found a fix. Right now the problems are happening with EGP and HIP reflective 3M brand. We are printing using 3Ms profiles for the media. When We print a NO Parking sign we get these areas where the vertical alignment seems to go out of wack and the text gets fuzzy. Sometimes its for .5" and other times it goes for 2-3". It will happen and then correct itself and go for another foot or two and then do it again. It's also drastically changing the vertical length of these prints. 12x18 are coming out 12x17.5" or worse. The lines that run vertical on the print or super clear so I don't think it's encoder strip. It's almost like sometimes it does .25" between passes and then other times decides it only wants to move .1" between passes and other times decides it wants to move further then it's supposed to. Attached are pictures. You can see the map starts printing clean and then becomes worse and then starts to get better as the next lines of text come up. What makes me think it's the OMAS and the reflective is that as soon as we switch to white vinyl the issue will go away. Go back to the reflective and the issues are back even if you print with the white vinyl profile.

We have tried:
Omas enabled
Omas disabled
OMAS calibration auto and manual
Printhead alignment auto and manual
Clean OMAS, encoder, rails, pinch rollers, platten, printheads
Take up reel connected and disconnected
Printing on the reflective with our old profiles
printing on the reflective with white vinyl profiles

 

[dypinc]

If you have the same problem with OMAS disabled. Have you tested the tension settings?

 

[BIG EASY DOES IT]

No. I haven't. Haven't seen a test for this. Could you point me to where I could find that in the service manual.

 

[dypinc]

Don't know that there is a test for this other than to try different settings and see if it would make any difference. If it appears not to be feeding enough then I would think the media might be slipping in the pinch rollers because of too much tension. If it is feeding too much then the only thing I can think of is the OMAS or take-up reel but you have said that you have tried with both of these disabled. Both at the same time?

 

[BIG EASY DOES IT]

Yes tried both with both disabled at same time also. And combination of both. I would say the majority of these bad prints are coming out shorter then they should be. I was thinking since the backing is plastic the pinch rollers slip every once in a while especially if there is some back tension. So it never fully moves forward the full amount. Is there a way to lower the tension on the roll holder?

 

[dypinc]

Yes in the Media Preset there is a tension setting. You can make that adjustment while it is printing or in the Advanced section of the Media Preset.

 

[Christian @ 2CT Media]

Try reducing tension and even vacuum... It sounds like you are having a feed issue

 

[colin smyth]

Was going to mention vacuum setting, though have had similar problems and also found that a clean and lubrication aisles sorts it (even though no maintenance errors show)

 

[papabud]

i would also say its a feed issue. you might wanna check the material feed motor. it could have a loose connection lowing the power to fade for a second.

 

[BIG EASY DOES IT]

Thanks guys. I'll give some of these things a try and report back later this afternoon. I'm also going to try 16 and 20 pass on the profile. Maybe moving slower is a better idea.

 

[AF]

Clean the media spindle grippers.

 

[BIG EASY DOES IT]

Spindles Clean,
Drive Roller Clean,
feed motor and tension has to be correct all medias except EGP, HIP, and DG come out perfect
Not sure what else I could try at this point
16pass is better
Say I print a 12x18 on 12 pass. It's going to be 12x17.75
I print the same 12x18 on 16 pass. It's 12x17.95
We can make this work for small signs but we do 60x96 and 72x120 all the time. If my print comes out 1" or more short I am screwed.

 

[dypinc]

If it consistently comes out 1" shorter there is an feed adjustment in the Media Preset for that or also in your RIP.

 

[BIG EASY DOES IT]

No. This is very inconsistent. Sometimes at the start of a print, sometimes in the middle of a print, sometimes prints come out perfect. Is there a way to slowdown the advancement without changing the number of passes. If the printer always moves the media at a certain speed is there a way to change the speed? I know I would drastically change the print time. But if I can't use the prints then the print time is wasted anyways.