Editing Pen (section)

===Modern===
[[File:Macro Biro tip.jpg|alt=Close-up picture of the tip of a ballpoint pen showing the ink-covered ball.|thumb|Writing tip of a ballpoint pen and 1mm white bar for scale]]

Pens commonly used today can be categorized based on the mechanism of the writing tip and the type of ink:

* A '''[[ballpoint pen]]''' dispenses a [[Viscosity|viscous]] oil-based ink by means of a [[Ball bearing|small hard sphere]], or ball, which rolls over the surface being written on. The ball is held captive in a socket at the tip of the pen with one half exposed and the other half immersed in ink from the pen's reservoir. When the ball rotates, it transfers the ink - which [[Wettability|wets]] the ball - from the reservoir to the external surface. The ball is typically under a millimeter in diameter and made of [[brass]], [[steel]], or [[tungsten carbide]].<ref>{{cite web |title=How does a ballpoint pen work? |work=Engineering |publisher=HowStuffWorks |date=1998–2007 |url=http://science.howstuffworks.com/question683.htm |access-date=2007-11-16 |archive-date=2018-12-25 |archive-url=https://web.archive.org/web/20181225032127/https://science.howstuffworks.com/innovation/science-questions/question683.htm |url-status=live }}</ref> The ink, due to its high viscosity, does not [[Permeation|permeate]] through paper and does not leave the tip of the pen by [[capillary action]]. As such, a bare minimum amount of ink is dispensed, with the result that the writing dries almost instantly and ink lasts longer than it does in other types of pen.  Ballpoint pens are reliable, versatile and robust, and are available for a very wide range of prices. They have replaced fountain pens as the most common tool for everyday writing.
* A '''[[gel pen]]''' works similarly to a ballpoint pen, in that it dispenses ink using a rolling ball held in the writing tip. However, unlike oil-based ballpoint pen ink, gel pen ink consists of a [[water]]-based [[gel]]<ref>{{cite journal|last=Schwartz|first=Debra A.|date=September 2001|title=The Last Word: Just for the gel of it|url=http://pubs.acs.org/subscribe/archive/ci/31/i09/html/09lw.html|journal=Chemical Innovation|volume=31|issue=9|page=IBC|access-date=2018-04-08|archive-date=2020-07-15|archive-url=https://web.archive.org/web/20200715202714/http://pubsapp.acs.org/subscribe/archive/ci/31/i09/html/09lw.html|url-status=live}}</ref> that has a [[pigment]] [[Suspension (chemistry)|suspended]] in it. Because the ink is thick and [[Opacity (optics)|opaque]], it shows up more clearly on dark or slick surfaces than the typical inks used in ballpoint or felt tip pens. Gel pens can be used for many types of writing and illustration. Since the gel medium eliminates the constraints of a soluble dye, many new colors are made possible, as well as some special types of ink; gel pens are available in a wide range of vibrant or saturated colors, in pastel colors, in [[Fluorescence|neon]] colors, in [[metallic color]]s, in [[glitter]] inks, in [[Phosphorescence|glow-in-the-dark]] ink, and so on.
* A '''[[rollerball pen]]''' is a pen that dispenses a water-based ink through a ball tip similar to that of a ballpoint pen. As such, gel pens might be considered a subcategory of rollerball pens; however, due to the widespread knowledge and use of the term 'gel pen', 'rollerball' is in practice typically reserved for pens which use liquid ink.<ref>{{Cite book |last=Florey |first=Kitty Burns |url=https://books.google.com/books?id=c7CRrquqifEC&dq=A+rollerball+pen+is+a+pen+that+dispenses+a+water-based+ink&pg=PT70 |title=Script and Scribble: The Rise and Fall of Handwriting |date=2013-10-08 |publisher=Melville House |isbn=978-1-61219-305-2 |language=en}}</ref>  The lower viscosity of rollerball ink compared to oil-based ballpoint pen ink has several effects on the pen's performance. Since the ink flows more easily and is more easily absorbed into paper, more ink is dispensed in general. This changes the writing experience by lubricating the motion of the tip over the paper. It also results in a solid and uninterrupted line, since the diffusion of the ink through the paper fills small gaps that might otherwise be left by the ball point. Compared to ballpoint pens, which dispense a smaller amount of more viscous ink, the writing by a rollerball pen takes longer to dry on the page and can seep through thin paper such as to become visible on the opposite side. When the tip of a rollerball pen is held against paper, ink leaves the tip continually by capillary action in much the same way as would occur with a fountain pen. This can lead to ink blots or smears. The rollerball pen was initially designed to combine the convenience of a ballpoint pen with the smooth "wet ink" effect of a fountain pen. Refillable rollerball pens have recently become available; these generally use cartridges of fountain pen ink.
* A '''[[felt tip|felt-tip pen]]''', or [[Marker pen|marker]], has a [[Porous medium|porous]] tip made of fibrous material, which normally remains saturated with ink from the reservoir.<ref>{{Cite book |last1=Sgamellotti |first1=Antonio |url=https://books.google.com/books?id=Zd7yDwAAQBAJ&dq=A+felt-tip+pen,+or+marker,+has+a+porous+tip+made+of+fibrous+material&pg=PA120 |title=Science and Art: The Contemporary Painted Surface |last2=Brunetti |first2=Brunetto Giovanni |last3=Miliani |first3=Costanza |date=2020-07-01 |publisher=Royal Society of Chemistry |isbn=978-1-78801-469-4 |language=en}}</ref> As ink leaves the tip, new ink is drawn from the reservoir - which often consists of a large volume of a similar porous material to that used in the tip - by capillary action and gravity. As with a fountain pen, ink leaves the tip of a felt tip pen by capillary action when writing on a porous surface. However, unlike fountain pens, many markers can also reliably write on slick impermeable surfaces that are [[Wetting|wet]] by the ink, and in such applications ink typically does not continually leave the pen as it is held against the writing surface. The smallest, finest-tipped felt-tip pens are used for writing on paper. Medium-sized felt-tips are often used by children for coloring and drawing. Larger types, often called "markers", are used for writing in larger sizes, often on surfaces other than paper such as corrugated boxes and [[whiteboard]]s. Specialized felt-tip pens referred to by names such as "liquid chalk" or "chalkboard markers" are used to write on [[Blackboard|chalkboards]]. Markers with wide tips and bright but [[transparency and translucency|transparent]] ink, called ''[[highlighter]]s'', are used to highlight text that has already been written or printed. Pens designed for children or for temporary writing (as with a whiteboard or overhead projector) typically use [[non-permanent marker|non-permanent]] inks. Large markers used to label shipping cases or other packages are usually [[permanent marker]]s.
*A '''[[brush pen]]''' is a pen whose writing tip consists of a small [[brush]] fed with ink from a liquid ink reservoir similar to those used in fountain pens and rollerball pens.<ref>{{Cite book |last=Stephenson |first=Jonathan |url=https://books.google.com/books?id=h05QAAAAMAAJ&q=brush+pen |title=Graphic Design Materials & Equipment: An International Directory |date=1987 |publisher=Chartwell Books |isbn=978-1-55521-078-6 |language=en}}</ref> Brush pens might be either refillable or disposable, and might use either water-based or waterproof ink. The most significant functional difference of brush pens from felt-tip pens is the far greater [[Compliance (mechanics)|compliance]] of the tip. Brush pens are an obvious alternative to [[ink brush]]es for [[Chinese calligraphy]] and [[Japanese calligraphy]], but are now also commonly used in other forms of calligraphy and by artists such as illustrators and cartoonists. The primary appeal of these pens to such artists is that they allow a great deal of line width variation in response to small changes in applied pressure.
* A '''[[stylus pen]]''', plural styli or styluses,<ref>{{cite web|url=http://dictionary.reference.com/browse/stylus|title=Stylus - Define Stylus at Dictionary.com|work=Dictionary.com|access-date=2018-04-08|archive-date=2016-03-04|archive-url=https://web.archive.org/web/20160304045520/http://dictionary.reference.com/browse/stylus|url-status=live}}</ref> is a [[writing utensil]] which does not use ink, but rather makes marks primarily by creating scratches or indentations in the writing surface. As such, the tip often consists simply of a sharp metal point. Such tools are also used for other types of marking than writing, and for shaping or carving in, for example, [[pottery]]. The word stylus also refers to a pen-shaped computer accessory that is used to achieve greater [[Accuracy and precision|precision]] when using [[touchscreens]] than generally possible with a fingertip. There are products available that combine a ballpoint tip at one end and a touchscreen stylus at the other.
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<gallery widths="200px" heights="160px">
File:Gel pen versus ballpoint pen.jpg|alt=Picture of writing tips of a gel pen and a ballpoint pen lying on a piece of paper next to lines created by each pen.|Lines created by a gel pen (top) and a ballpoint pen (bottom)
File:GelPen.jpg|A gel-based rollerball pen
File:Fude pen.jpg|alt=Picture of a brush pen being used to apply ink to paper.|A brush pen
File:Fountain-pen-nib.jpg|alt=Picture of the writing tip of a fountain pen.|The writing tip of a fountain pen
File:Felt Tip.jpg|alt=Picture of the fibrous writing tip of a felt-tip pen|The writing tip of a [[Marker pen|marker]]
File:Lenovo-X61-Tablet-Mode.jpg|alt=Picture of a computer stylus lying on the touchscreen of a laptop folded backwards into tablet mode.|Computer with computer stylus
</gallery>