User guide

Q: I have banding in my print. How do I get rid of it?
A: Before you can get rid of banding in a print, you need to have an understanding
of what caused the banding. There are several types of banding that can occur
and each it’s own solution. Here is a brief description of the different types of banding
and what can be done to combat them. Start with NO misdirected or missing nozzles.
Chromatic Banding: Chromatic banding it the most typical form of
banding in piezo inkjet printers. It takes it’s form as a series of alternating color
shifts from light to dark. It occurs most often when printing in bidirectional modes
and is due to the change in the order that ink is laid down from one pass to the
next. In four color mode the Mutoh Falcon Outdoor II was designed to reduce
the effects of chromatic banding by providing two separate channels of each
color in a mirroring fashion. This ensures that when printing in bidirectional mode
ink is laid down in the same order in both passes.
Banding due to incorrect Step (Distance) Adjust: Step adjust is the most
common type of banding to users who are new to the product. Media is fed through the
printer using a grit roller assembly and a series of pressure rollers which hold the
media to the grit roller. All medias have a different composition and are gripped
differently by the grit roller. Some medias are soft and grip well. Others are hard
and smooth and may slip slightly when being fed through the printer. If a media
‘slips’ it will not feed far enough. This will cause dark overlap lines to appear at
the junction of every print pass. The default distance adjust setting on the printer
is 100.00% so to correct this problem the value needs to be changed to a larger
number, 100.25% for example. The opposite of this would be a media that grips
very well and actually moves through the printer at a faster rate than anticipated.
The result of this would be a white space (lack of ink) at the junction of every
print pass. The correction for this condition would be to lower distance adjust
value, for example changing the value from 100.00% to 99.85%.
Dot Gain Banding: Dot gain banding is a problem that can occur on the
Falcon II Outdoor due to it’s ability to print on uncoated materials. Outside of the
solvent world, inkjet printers print with water based inks onto specially coated
materials. These coatings are designed to dry the ink at the perfect rate to create
or ‘control’ the size and shape of the dot. In the last few years these coatings
have become so advanced that many ink jet printers can produce near photo
quality output. Back in the solvent world however, the idea is to print on standard
uncoated materials. Uncoated materials are much, much cheaper and are
designed to withstand the outside elements of the world. With no special coatings
to control the dot size or ‘dot gain’ another method of controlling the ink is
needed. The most obvious of these is heat. The more heat you can apply to the
ink the faster it will dry, the more control you have over the final dot size. Dot
gain banding is most noticeable in dark, solid fill colors and it the shadow areas
of photo images where larger amount of ink are printed and is a result of the
bleeding together at the junction of each printer pass. Dot gain banding can be
controlled by finding the optimum temperature settings for the media being
printed on and also by ensuring the proper linearization and profile for the media