"dropout" on grayscale gradient with SJ-745EX

[briant1362]

We're having problems printing a large grayscale gradient...not sure if you would call it "dropout" but every few inches the color fades out. Sometimes it's pretty regular (ie constant distance between dropouts)...sometimes not. The test print looks reasonable. We've checked bi-directional alignment and feed calibration. We've tried printing high quality, uni-directional, even changing to Density Control Only. We've performed a manual and normal cleaning. Also replaced the dampers per the recommendation of a local Roland supplier. Nothing seemed to work. We're printing on Oracal 3651RA. The file is CMYK with the gradients going from 0/0/0/100 to 0/0/0/20. Any suggestions/recommendations?

Thanks in advance.

 

[stopngo]

of you can post pictures or supply the file then we may have more to go on. just a suggestion.

 

[Malkin]

If you print this same file twice with no changes to any settings, are the results exactly the same, or are they different?

 

[Jester1167]

I'm guessing is has something to do with you color linearization. We need to get out output calibrated too. Gradients are tough and greys are even worse. The RIP plays a big roll. The last update we got to Wasatch smoothed out our gradients considerably.

 

[cdiesel]

Are you printing a vector or raster?
I'd bet it is a RIP issue and not a mechanical problem with the printer. We've found a few of the profiles in Versaworks that do very odd things with gradients.

 

[briant1362]

Attached are a couple of pics...they're not the best but I think you can see what I'm describing. We get similar results with multiple prints but I don't think they're "exactly" the same...ie the dropouts seem to be in different areas and have different levels of fading, but we're also re-printing with diff settings. We're using VersaWorks to rip...have everything except the very last update applied. We've been printing the gradient as a vector...I like the rasterization idea and will try that next.

 

[Graphics2u]

Are those running with the print direction or with the paper feed direction?

 

[John Butto]

Photoshop

Bring the gradient into Photoshop and follow these directions: These are the best methods to non-destructively apply the necessary noise to a gradient.

1 - apply a pattern overlay layer style. First you generate a noise pattern (6 or 4% monochromatic noise applied to a neutral 128,128,128 grey ) and blur this noise by a tiny amount 1 or 2 pixels. Then make a seemless pattern from this about 200 pixels square. Then go to the pattern overlay layer style. Blend the pattern using Overlay or Soft Light at 70% opacity.

2 - make a new layer. Fill with the pattern generated above or just fill the layer with gray and noise/blur it. Blend 70% using Soft Light or Overlay

 

[Bly]

How are the test prints black especially?
Been a while since it had a really good clean?
What heat are you running?

 

[briant1362]

The fades are parallel to the print head. I tried rasterizing the gradient in Illustrator, as well as the Photoshop noise/blur trick, and got the same results. I also tried different media and had the same problem. Attached is a blurry pic of the test print. We're running the heater at 42c. We did a good manual cleaning when we first had issues with this job (though we do regular cleanings once a week). I would think that the test print would be worse than it is if it were a cleaning issue?

One other observation, when I print the gradient with all 4 colors (instead of just black) the colors are off (lots of magenta and blue tint) but the fading problem is much less apparent. Maybe there is more ink being put down, effectively "hiding" an issue with the black?

I left a message for Roland on the tech support line...hopefully I can get a service tech out to take a look first hand.

 

[stopngo]

Have you tried printing with the heat completely off? This could be an issue with your heaters drying the print unevenly

 

[cdiesel]

What profile and media are you using? It definitely looks like a RIP issue and not mechanical.
Do you have RolandColor installed? I'd get it installed and make the gradient go from BK21A to BK05A.

 

[briant1362]

We were using Orajet 3165RA with GCVP media/profile. We ripped from Flexi and got similar results. That, combined with results from the rasterizing suggestions, make me think it's a hardware issue.

Roland tech support never got back to us. In the end, we had to get our local Roland supplier to run the prints for us on one of their new Roland printers (not sure which model).

 

[Pacific Coast Sign]

Possible bad damper... And what is the head height set at, it should be on low. You have a good combination media and profile. Also, lower your heater temp..possibly set too high.

 

[briant1362]

We replaced the dampers early on per the suggestion of local Roland dealer. The head height is set to middle. We rarely change head height unless we need tighter, more detailed prints which are usually much smaller than this 4'x8' print. That's two suggestions regarding heat settings so I think I'll experiment with that.

I'm thinking another useful test would be to print some other single ink gradient...like magenta. That should help isolate my theory that is a blank ink flow problem.