Editing Rollerball pen (section)

== Advantages ==
[[File:UniballElitePenTip.jpg|thumb|Close up of an extra fine roller ball pen next to something written with it]]

Rollerball pens were introduced in 1963 by the Japanese company [[Ohto]].<ref>{{Cite web |url=http://www.ohto.jpn.org/ceramic.html |title=Ceramic Ball (OHTO Japan English Website) |publisher=ohto.co.jp |year=2008 |accessdate=4 May 2012 |deadurl=yes |archiveurl=https://web.archive.org/web/20120318202440/http://www.ohto.jpn.org/ceramic.html |archivedate=18 March 2012 |df= }}</ref> There are two main types of roller ball pens: liquid ink pens and [[Gel ink pen|gel ink pens]]. The 'liquid-ink' type uses an ink and ink supply system similar to a [[fountain pen]], and they are designed to combine the convenience of a [[ballpoint pen]] with the smooth "wet ink" effect of a [[fountain pen]].

Gel inks usually contain [[pigment]]s, while liquid inks are limited to [[dyestuff]]s, as pigments will sink down in liquid ink ([[sedimentation]]). The thickness and suspending power of gels allows the use of pigments in gelled ink, which yields a greater variety of brighter colors than is possible in liquid ink. Gels also allow for the use of heavier pigments with metallic or glitter effects, or opaque pastel pigments that can be seen on dark surfaces.

Liquid ink roller ball pens flow extremely consistently and skip less than gel ink pens do. The lower viscosity of liquid ink increases the likelihood of consistent inking of the ball, whereas the higher viscosity of gel ink produces "skipping", that is, occasional gaps in lines or letters.

In comparison to ballpoint pens,

* 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, saving energy and improving comfort. This can also translate to quicker writing speeds. This is especially true of liquid ink pens.
* The inks usually have a greater range of colors due to the wider choice of suitable water-soluble dyes and/or to the use of pigments.
* They tend to write more clearly than ballpoint pens do.