Pen

A pen (Latin: penna, feather) is a writing implement used to apply ink to a surface, such as paper, for writing or drawing.Historically, reed pens, quill pens, and dip pens were used, with a nib dipped in ink. Ruling pens allow precise adjustment of line width, and still find a few specialized uses, but technical pens such as the Rapidograph are more commonly used. Modern types also include ballpoint, rollerball, fountain, and felt or ceramic tip pens.

Types of pens

Modern
The main modern types of pens can be categorized by the kind of writing tip or point:

A ballpoint pen dispenses ink by rolling a small hard sphere, usually 0.7–1.2 mm and made of brass, steel or tungsten carbide.The ink dries almost immediately on contact with paper. The ballpoint pen is usually reliable and comes in both inexpensive and expensive types. It has replaced the fountain pen as the most common tool for everyday writing.
A fountain pen uses water-based liquid ink delivered through a nib. The ink flows from a reservoir through a "feed" to the nib, then through the nib, due to capillary action and gravity. The nib has no moving parts and delivers ink through a thin slit to the writing surface. A fountain pen reservoir can be refillable or disposable, this disposable type being an ink cartridge. A pen with a refillable reservoir may have a mechanism, such as a piston, to draw ink from a bottle through the nib, or it may require refilling with an eyedropper. Refill reservoirs, also known as cartridge converters, are available for some pens which use disposable cartridges.
A marker, or felt-tip pen, has a porous tip of fibrous material. The smallest, finest-tipped markers are used for writing on paper. Medium-tip markers are often used by children for coloring and drawing. Larger markers are used for writing on other surfaces such as corrugated boxes, whiteboards and for chalkboards, often called "liquid chalk" or "chalkboard markers." Markers with wide tips and bright but transparent ink, called highlighters, are used to mark existing text. Markers designed for children or for temporary writing (as with a whiteboard or overhead projector) typically use non-permanent inks. Large markers used to label shipping cases or other packages are usually permanent markers.
A rollerball pen dispenses a water-based liquid or gel ink through a ball tip similar to that of a ballpoint pen. The less-viscous ink is more easily absorbed by paper than oil-based ink, and the pen moves more easily across a writing surface. The rollerball pen was initially designed to combine the convenience of a ballpoint pen with the smooth "wet ink" effect of a fountain pen. Gel inks are available in a range of colors, including metallic paint colors, glitter effects, neon, blurred effects, saturated colors, pastel tones, vibrant shades, shady colors, invisible ink, see-through effect, shiny colors, and glow-in-the-dark effects.