Gel pen
From Wikipedia, the free encyclopedia
Gel pens are gel inked ballpoint 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.
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[edit] Design
The general design of a gel pen is similar to that of a ballpoint pen, with a barrel containing the writing mechanism and a cap. Most gel pens have grips, some made of rubber and some of plastic.
What distinguishes a gel pen from a ballpoint pen is the gel ink which consists of pigment suspended in a water-based gel.[1] The pigments are typically copper phthalocyanine and iron oxides, and the gel is made up of water and biopolymers, such as Xanthan gum and tragacanth gum, as well as some types of polyacrylate thickeners. Since pigments are 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 pens use a dye solute in a water-based solvent. India ink (based on 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.[citation needed]
Another trait of gel pens is that they resist common laboratory analysis. The American 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 (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.[2]
[edit] Types
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, mint, vanilla, pineapple, banana and coffee.
[edit] 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 pigments are used, e.g. phthalocyanine dyes, carbon black, or iron oxides.
- 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 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-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.
[edit] Disadvantages
- Consumes ink rapidly
- Cease of ink flow has been reported on some gel pens, especially colour gel pens
[edit] See also
[edit] References
- ^ The Last Word: Just for the gel of it
- ^ LaPorte, Gerald (May 2006). "An Evaluation of Matching Unknown Writing Inks with the United States International Ink Library". Journal of Forensic Science 51 (3): 689.
