Can anyone suggest anything I can do with banding on print

[Jason Xuereb]

How do you store your rolls?

[Jason Xuereb]

Have you tried cutting a piece of vinyl say 1m by 1m and rotating it 90 degrees and printing on it to see if its the media or the printer/profile?

[Simon Worrall]

Jase…

The printing rolls are stored in purpose built racks under the glass tables shown in this pic. They are suspended with bars down the cores, horizontally, under no pressure.
They are stored in the same room as the printer and my whole studio. The temp doesnt really vary much. It is comfortable room temperature.

The rolls you see sitting on the corrugated shelf are waste material, and coloured non printing vinyl.

I think this is okay storage, but I will try turning the media 90 degrees as you suggest just to make sure, and post results.
Good idea.

Simon.

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[John Thomson]

Could it be tension on the media?
Try unrolling some to eliminate this as a possibility.

John

[Glenn Sharp]

I’ve had similar problems Simon and never really found a solution which has worked everytime….

I put our problems down to the file rather than the media and I always assumed it was the fountain steps created in Corel that weren’t converting properly in the rip

I had some success converting the background fade to a bitmap…it will probably throw your colours out but all I did was create a new colour swatch to pick from by converting the pantone chart to JPEG and printing it

I could be way off but it always seemed to happen when the background was a fade so I always assumed it was a file problem and not the media

[Jon Marshall]

Have you got another RIP you can try?

[Gareth Morgan]

I have a Mutoh Valuejet, which has the same problem. I found adjusting head height to high worked. Not sure if you can do this with the sp540v tho.

[Stuart Drynan]

I used to get this issue all the time, It turned out to be static and heat issues….

Im sure i was advised that it was caused by to high a heat drying the heads out..

Ive never had the issue since changing companys tho so not 100% on wither it is really a heat issue or not tho..

[Simon Worrall]

John. It is definitely not tension. I always unwind the roll first.

Glenn, I will try rasterising the fade this morning, This sounds promising..although quite confusing…

Jon I have never used anything else but versaworks.

Gareth head height helps a bit, I tried that before.. it seems to "blur" the droplets a bit before they land on the media. Not enough for these bands though.

Stuart I started printing without heat a few months ago to fix the print cut alignment issues with the roland. I dont use heat any more. Maybe some would help?
I am not sure how to deal with static. Connect the metal media rollers to the earth? Certainly it could be that.

Last night I cranked up the calibration to 0.9, and it seems to have helped a bit but you can still see the banding. It is subtle but ugly.

The day is just beginning here in NZ, and I will get into this with all your suggestions later on.

Simon.

[Stuart Drynan]

quick thought..

are you bi-directional printing or uni-directional?

Im trying to remember how i fixed this issue….. It was identical to what you have and im sure it was something to do with static build up etc and heat.

On our sp540v i tend to run it very slow, that usually kills any static build up it gets..

[Simon Worrall]

I am bi directional Stuart. (Cant help chuckling. Lets not go there!)

I usually print at around 600mm/second. Never thought that would affect static, but now you mention it, maybe I should slow that down.

It is printing right now. I have bumped up the calibration to 1.05.
The banding is gone, but it has been replaced with "overlap" banding, which I can live with as it cannot be seen from a few steps away, and it is far less ugly.

When I do the calibration test print it prints correctly at around 0.35 – 0.4 with no overlap or gaps between the passes. So 1.05 is very high.

It is not really a fix, just a work around, and it will get me out of the woods with this job.

[Chris Wool]

My guess is static and low humidity what’s the weather like down there.
Have a look at the spray patterns between the light er and dark areas with a good magnifying glass are there traces of odd colours in one area that’s not in the other.
Give the machine a good wipe down all over with a damp cloth.

[Stafford Cox]

Hi Simon. I know you say you’ve done the calibrations and I don’t mean to insult your intelligence as I don’t know how ‘in depth’ you do the calibrations. But have you checked the head slants? If this were a Mimaki I would look straight at the slant and unit adjustments. Also, when doing the calibrations, do you do them by eye or using a magnifier (loupe, scope?).

Those DX4 printhead a really do need to be calibrated to within an inch of their life to get a good, true solid colour. You need to make sure they’re aligned to the dot, rather than to the line. Granted, Roland’s don’t seem to be as critical as Mimaki’s do but that’s where I would look first.

Let me know if you need any pointers.

Stafford

[Simon Worrall]

Chris the pattern is quite different on the bands from the good areas – seems a bit more grainy, and as you say there are odd specks of colour. I have wiped down the machine and will continue to do that as a matter of course from now on. It is winter here, we have the heat pump on, which I suppose dries out the air, making static very likely.

Stafford I have no idea what Head Slant is.
I mean I guess it is obvious from the name, but I didnt know that was even an option.
Does anyone else reading this, with a Roland, have a clue about this and how to do it? I have been through the menu options on the machine and I dont see anything there.
Maybe it is a technician only thing?

[Chris Wool]

Thinking a bit out of the box as the media is stored under the glass top the next new roll keep away from the bench.
I to use a glass work bench and now it can generate static whilst weeding which may be charging the roll. And may account for the regular spacing of the affected area.

Head alignment is to see if the heads are square to the direction of the bed and is in service mode.

[George Elsmore]

Have you turned down the vaccum power down a bit I had a certain vinyl once(name escapes me) but it banded where the vacuum holes were

just a thought

[Simon Worrall]

George I will try different vacuum settings.

Chris, I suspect that you might have a point about the tables. They are big steel frames, on wheels with a glass top.
A big rubber coated roller (solid steel cylinder coated with rubber) goes up and down the tables which I use for laminating .

Its obvious now! (Idiotic Eureka Moment!) This is definitely a HUGE source of static!

I even get shocks sometimes when I use the roller!

I will earth the frames. That will help . DOH!

😳

[Stafford Cox]

I think the term in Roland language is BIAS adjust. I’ll check when I get home and post more accurate description….

Stafford

[Stafford Cox]

Yeah, it’s BIAS first, then vertical adjustment, then horizontal adjustment. You need to set the calibration correctly for D1, D2 etc, then run bi-directional adjust for the same. It seems not to be as critical on Roland and Mutoh as it is on Mimaki but I’d make sure it’s right first before spending money on parts to try and eliminate it.

Best of luck

Stafford

[Nigel C]

Large flat colours are a real pain – not an ideal solution but if I had any banding problems and needed to get job out I would redo background colour in photoshop adding some monochromatic noise to break it up. Prints looked v slightly grainy but it used to the cure banding.
Also have you tried different media profiles?
Good luck

[Simon Worrall]

Stafford that information is well over my head. Sounds like engineer’s speak. Is that in service mode? I dont even know how to get there.
I have not really fixed the problem but I managed to get out the job in question using very high calibration numbers which meant the machine was overprinting narrow bands.
The customer was very happy with it, we put it up before he had a chance to look closely, (!) and once it was up (5 meters above the pavement) you needed to really stare to see any inconsistencies.
I will try the photoshop thing and the head levelling, but I am quietly confident it is static thats causing the problem. I just need to work out how to keep it at bay.

Thanks for all your suggestions.

Simon.

[Stafford Cox]

Excellent. As long as the work was output successfully, there’s no need for any more work to be done on it. The BIAS adjust is in the service mode so if you need talking through it at any point, get in touch.

Stafford

[Andrew Weaver]

Hi,

I had similar troubles that were due to dust on the encoder strip.
Once cleaned things went back to normal and I do quite à lot of large flat colours.

I also noticed that one of my flanges that I put the roll on wasn’t a great fit and sometimes would go a little slanted which I think also stopped the vinyle from moving freely !

Let us know what the solution was in the end … hoping that you did find a solution !!

Good luck

[Simon Worrall]

I have cranked up the calibration to a point well beyond the adjustment. (the machine prints two grey blocks and if they overlap its too much and if there is a gap its too little) Now I push it up to where it very much overlaps on the test print, but this seems to print very well on the actual print itself.
Whether something has slipped or worn so it is inaccurately doing a test print I dont know, but it seems to be working pretty well now.
I also keep the machine wiped down with a damp cloth.

Thanks for the replies.
Simon