White dots on print (fisheye)

Fisheye is a problem that can lead technicians and users to replace parts needlessly. There is
one fact that’s important to remember about Fisheyes; IT’S VIRTUALLY NEVER THE PRINTERS
FAULT.

The reasons for Fisheye are as follows:
1. The media has a defect in the coating which is causing the ink to vacate that spot. In these
instances locate the lot number on the box of media and contact the media manufacturer or
supplier where the media was purchased.
Save the defective print sample to return with the roll.

2. There are foreign substances on the media. Most often the fish eyes are caused by airborne
particles landing on the media before it enters the printer.
Be sure your printer is not located under an air conditioning vent, next to an engraver or router
table and not in the breeze of an open door. It’s also possible, but less likely, for the debris to be
coming from inside the printer.

Be sure to check the inside of the printer for debris that could be caused by previous media,
lack of maintenance, etc.

Now we’ve established there are only two reasons Fisheye can show up in the output from your
printer. Keep in mind how the printer works as it is printing. Hundreds of small nozzles are firing
ink at a precise rate to give the appearance of an image.

In Roland devices, each particular point on the media will be passed over a minimum of 4 times
by several different sets of nozzles on the same printhead. Add additional printheads depending
on what printer model is being used and there is too much redundancy for the printer to miss a
single spot (or several single spots) when printing. It is just about physically impossible.

Another component that gets blamed for Fisheyes is often the heating system. Also, keep in
mind that there are two or three heaters running the length of the platen on each Roland device. Any malfunction of the heating system would most likely be shown across the entire width of the
media. Prints that have heating problems can give a streaky or orange peel look to the prints, not
areas completely devoid of colour.

Sample Images

1. Classic Fisheye.
You can see the white area surrounded by a
darker area which indicates that the ink has
vacated off of the white area. This makes the
area around the white area darker from the extra ink
that has moved from the white area.

2. Orange Peel Effect.
This image shows one white spot in the centre
of a black-printed area. The other light areas shown
in this image may be confusing because they are
imitating a fisheye. This is actually an orange peel
effect that is from the print profile being incompatible
with the media or running on a heat setting that is
too low.

3. Multiple Effects
In this image, there are two defects. One is a fish eye
and the other looks to be a short line with a curve.
This type of print defect would be caused by a fibre on
the printed surface. The same grain shown here as the
print above could be from the orange peel effect or from
having the bidirectional adjustment incorrectly set.