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Rollerball pens are pens which use
ball point writing mechanisms with water-based liquid or gelled ink, as opposed
to the oil-based viscous inks found in ballpoint pen.
The characteristics of these less viscous inks, which tend to saturate more deeply
and more widely into the paper than other types of ink, give rollerball pens their
distinctive writing qualities.
The rollerball pen was initially designed to combine the convenience of a ballpoint pen
with the smooth “wet ink” effect of a fountain pen
There are two types of rollerball pens: those that use a liquid ink and those that
use a gelled ink.
Gel rollerball pens use a jelly-like ink: the ink thins as it moves past the ball
and sets back up just after it is applied to the paper and is no longer being “rolled”
around. Because the gel inks set so quickly, they are not absorbed into paper fibers
as much as liquid ink. Using a gel ink pen, one may often write on both sides of
the same piece of paper. With a pure liquid ink pen, the ink is often thin enough
that it will soak through or “bleed” through enough of the entire paper to make
the second side of the paper totally unreadable if written on.
Gels usually contain pigments, while liquid inks are limited to dyestuffs, as pigments
will sink down in liquid ink sedimentation). It is the thickness and suspending
power of gels that allows the use of pigments in gelled ink. Using pigments (the
same pigments that are used in paint) yields a greater variety of brighter colors
than is possible in liquid ink, so gel-based pens are available in a brighter and
wider range of colors than liquid ink pens. Also, some gel ink pens can use the
heavier pigments with metallic or glitter effects, or opaque pastel pigments that
be seen on dark surfaces, because their gel ink suspends pigments so well.
Advantages over ballpoint
A rollerball has three advantages over a ballpoint: first, less pressure needs to
be applied to the pen to have it write cleanly. This permits holding the pen with
less stress on the hand. Second, the inks are usually more brightly and variously
colored, due to the wider choice of suitable water-soluble dyes, or to the use of
pigments. Third the ink is more secure that ball point ink. Ball point
ink can be chemically removed from checks in a process called Check Washing.
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