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Banding on edges – But not in middle!!!
Has anyone seen this on any printers? The printer in question is a mutoh toucan, but I think what causes it may be similar accross the board. It will print a perfect block of colour with temperature off(less than 25 degrees c), as soon as the temperature on the platen is on above 25 a strange banding effect is seen on either one edge or both edges. Usually not the middle. This effect comes and goes. Temperature sensors have been replace in the platen, as have the heating elements. Distance adjust seems right also. This appears on several different media. The only odd thing I can see happening is that the media shifts to the left side about 5mm in the first few few metres of print, then stabilises. This is independent on the takeup. Any thoughts would be much appreciated as I’m really grasping at straws.
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7 Replies
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humidity may be playing a part here i noticed some vinyl makes expand at the first few metrs giving this run out and the print degrades – from experience – changed makes problem solved
chris
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Eddie, where are you based mate?
Do you run the roll out for a few metres before your go back and start printing?. Sounds like a tight roll to me, but I’ve only experienced this on banner material. I get banding if I use a new full roll, and let the machine pull it thru as it prints.
If I run the material thru first to loosen the roll, it does not happen.
Sorry I can’t be more help
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I agree with eveything said. Ive had problems with begining and end or roll before. Mainly at the end last few mts. Where the vinyl is "tenting" you get more ink less heat etc.
Also profiles have a huge part to play.
Hope this makes sense?
Matt
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I’m in melbourne Shane. I normally load it up pulling through a few meters of media, then activate the rear winder to pull it back while I hold some pressure on it to get it straight. (All with the pinch rollers up). Once it’s pulled the media backa bit I lower the rollers.
The media is kept in the same room as the printers and is usually conditioned for at least 24 hrs. Several different media cause the same problem.
I had one theory recently I might check…..
At the rear of the machine, one of the dancer bars has a very slight bend in it (you can only see this if you spin it). Perhaps the media is warping as it passes over this bar….I’ll try and switch this bar with one from another machine….
Will try a few more things and let you guys know how I go. (For you interest)
Cheers,
Eddie -
yes.. the bars could be causing that problem… however shane is right regards the pull, i had that before where the machine is pulling and its not even or is a heavy roll.
Another thing is even heat, you said you have changed the heaters… so do you have a shorter width roll you can test with, place in different areas of the machine.
Is overprinting off?
Profiles again effect it… try a banner profile on vinyl… etc.
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Check to see that the covers are on the machine and that an air conditioning vent (or similar) isnt blowing straight down onto part of the bed. Also check other enviromental factors (Sunlight, fans, Hot laminating equipment etc) It really sounds to me like print bed temperature problem…..
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Thanks for your ideas guys! I will explore the issue further. 😀
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