Gel pen 3372324 220056513 2008-06-18T02:13:26Z Artichoker 4969156 rv [[Image:pens.jpg|thumb|right|200px|Gel pens]] '''Gel pens''' are gel inked [[rollerball]] type<ref>[http://www.wisegeek.com/what-are-gel-pens.htm "What are Gel Pens?"], ''WiseGEEK''</ref> pens. They come in many different sizes and in a huge variety of colours. They are primarily used for thin [[patterns]] or [[writing]], but can be used for colouring small areas in a specific colour. == Design == The general design of a gel pen is similar to that of a regular [[rollerball pen]], with a barrel containing the writing mechanism and a cap. Most gel pens have grips, some made of rubber and some of plastic. The main advantage of gel-ink is its lower [[viscosity]] or thickness. This allows it to dry more quickly so it smudges much less than a [[fountain pen]] or a regular rollerball pen. This also makes it less prone to absorb into the paper causing it to bleed through to the other side. [[Ballpoint pen]]s don't usually bleed through either, but gel ink is much bolder than regular ballpoint ink (though generally not as bold or thick as liquid-ink in fountain and other rollerball pens). The thickness of the ink has disadvantages such as skipping more than other inks due to the ball not being evenly coated. More ink is used compared to regular ballpoints, which is why they tend to run out much quicker than ballpoints. What distinguishes a gel pen from a regular ballpoint or rollball pen is the gel ink which consists of [[pigment]] [[Suspension (chemistry)|suspended]] in a [[water]]-based [[gel]].<ref>[http://pubs.acs.org/isubscribe/journals/cinnov/31/i09/html/09lw.html The Last Word: Just for the gel of it<!-- Bot generated title -->]</ref> The pigments are typically [[copper]] [[phthalocyanine]] and [[iron oxide]]s, and the gel is made up of water and [[biopolymer]]s, such as [[Xanthan gum]] and [[tragacanth gum]], as well as some types of [[polyacrylate]] [[thickener]]s. Since pigments are [[opacity (optics)|opaque]], gel pens are available in bright colours that stand out on darker paper. By contrast, ball-point pens use a paste ink based on a [[solution]] of a [[dye]] solute in an [[alcohol]] [[solvent]], and [[fountain pen]]s and liquid-ink [[rollerball pen]]s use a dye solute in a water-based [[solvent]]. [[India ink]] (based on [[Soot|carbon black]] pigment) is perhaps the ink closest to gel ink, although it is usually made with an alcohol and [[shellac]]-based binder. In other words, no other kind of pen (besides "paint pens") can write on dark paper and appear as bright as a gel pen. {{Fact|date=January 2008}} Another trait of gel pens is that they resist common [[forensic chemistry|laboratory analysis]]. The [[United States Secret Service]] has maintained the [[International Ink Library]] for many decades. Because manufacturers change their ink formulas slightly from year to year, [[Thin-Layer Chromatography|thin-layer chromatography]] (TLC) can be used on ink from traditional pens to trace the manufacturer and date of manufacture of most inks. The pigments in gel ink do not dissolve, and therefore cannot be analyzed with TLC.<ref>{{cite journal | first = Gerald | last = LaPorte | year = 2006 | month = May | title = An Evaluation of Matching Unknown Writing Inks with the United States International Ink Library | journal = Journal of Forensic Science | volume = 51 | issue = 3 | pages = 689}}</ref> == Types == [[Image:Gelpen cylindric tip detail.jpg|thumb|right|Detail of the tip of a gel pen]] There are several different types of pens. There are different sizes of nibs, ranging from 0.25 mm to 1.5 mm. There are also scented varieties, like [[chocolate]], [[strawberry]], [[mentha|mint]], [[vanilla]], [[pineapple]], [[banana]] and [[coffee]]. == Colours == The colours range from black to bright yellows. There are also several different styles of colouration: * Normal – These include ordinary colours like [[black]], [[blue]], [[red]], and [[green]]. Insoluble durable [[pigment]]s are used, e.g. [[phthalocyanine dye]]s, [[carbon black]], or [[iron oxide]]s. * Bright – These are bright colours that stand out, including [[yellow]], [[purple]], [[pink]], [[light blue]], [[orange]], [[gold]] (non-metallic) and the basic colours. Some are scented. * Metallic – These are the [[metallic paint|metallic versions]] of the normal colours including [[gold]], [[silver]] and [[bronze]]. These typically contain powdered [[aluminium]]. * Glittered – These are colours with [[glitter]] added to them to give a sparkly effect. Cosmetic-grade ground [[glass]] is used as the additive in [[Sakura of America|Sakura]]-brand pens. Some lose their glitter if "erased". * Milky – These are pastel colours, often pink, light blue, lavender, pale green, pale orange, and white. * Mixed – These are different colours mixed together in an ink for an interesting effect. These usually use [[pastel]] colours. == Disadvantages == * Consumes ink rapidly * Cease of ink flow has been reported on some gel pens, especially colour gel pens == See also == * [[Rollerball pen]] * [[Ballpoint pen]] ==References== {{reflist}} [[Category:Writing instruments]] [[Category:Pens]] [[de:Gelroller]]