Inkjet Film (PIJF)
The newest printers use pigment ink instead of dye ink because it resists fading
for up to 99 years. This improves family snapshots, but doesn't help the making
of UV opaque positives. The nano porous structure of the coating controls the ink
spread for image sharpness. Pigment ink particles are coated with a resin so they
can be controlled with piezo print heads.
Modern inkjet inks used for positives are water based and still need time to evaporate
and dry. Ink manufacturers need to balance nozzle maintenance and the desire to
have an ink that dries fast after printing, so a positive can be used to make a
screen. Glycol or glycerol humectants additives in the water based carrier that
are used to to keep the pigments in suspension, retard drying, and prevent nozzle
blockage need to evaporate the same way stencil coatings need to dry.
Ink dries on the nano particles of the coating
Very fast drying and instantly dry to the touch
Anti-Static Coating prevents sheets from sticking together
Absorbent Coating prevents ink moisture from sticking to stencil materials under
Imagine a nano porous coating as a jar of marbles. Pigment or Dye ink is absorbed
into the coating by capillary action and stains the microscopic particles in the
coating. It appears to be dry to the touch, but the liquid carrier still has to
evaporate. A benefit of the nano porous coating is that the positive can be stacked
and handled very quickly. If it is a humid day, the ink might not dry and the vacuum
of the exposure unit can pull the wet ink out of the film coating and stain the
stencil during exposure, because the positive has lost some ink during the process,
it shouldn't be used again.
Pigment Inkjet films are coated on 5 mil polyester. The coating loves water which
is the carrier for the ink. The polyester side is very shiny and doesn't absorb
water. You can test the film for the coated side by wetting your fingers and pinching
the film on both sides. The coated side will get sticky just like capillary film.
Rolls are coiled with the coated side out, ready to go into the printer.