How Does a Ballpoint Pen Work? – All Explained

Written by Laura Walker / Fact checked by Leilani Carroll

How Does a Ballpoint Pen Work

At first glance, a ballpoint pen seems like a simple tool, but how does a ballpoint pen work?

When the pen moves, the rotating ball transfers ink from the refill to the paper, continuously coating itself and creating smooth, uninterrupted writing.

Keep scrolling to understand the inner workings, pros, and cons of ballpoint pens to make the most of your pens.

Components of a Ballpoint Pen

  • Barrel: The barrel is the main body containing the internal parts of a ballpoint pen, typically made of plastic or metal. It usually has a nose cone (the pen tip) at one end.
  • Ink/ refill cartridge: The refill cartridge is a removable container that holds the ink inside of a pen.

It contains a ball at the tip – the pointed part of a pen, usually made of tungsten carbide or steel, that dispenses the ink onto the paper as it rolls.

  • Thrust device/ Cam: The thrust device is the mechanism that extends or retracts the refill. It can be a clicker or a twist mechanism, allowing the user to control when the pen tip is exposed.
  • Spring: A spring inside the barrel keeps the cartridge retracted until you’re ready to use the pen.
  • Top cap with clip: The top cap with clip is a removable cover that fits over the thrust device of the ballpoint pen.

You can check out the ballpoint pen diagram/ pen anatomy below:

The Working Mechanism of a Ballpoint Pen


The ballpoint pen mechanism includes 3 essential parts that work as a thrust device: the cam body, the tubular plunger, and the stop members.

  • The cam body is attached to the top of the replaceable ink cartridge and manipulates the ink cartridge’s position with each click, extending or retracting the pen tip.
  • The tubular plunger slides up and down without rotating while the stop members are fixed in place within the pen’s plastic tube.
  • They work together with the cam body to control the movement of the ink cartridge, enabling the pen to be extended or retracted.

1. Retractable mechanism

When the pen is retracted, the thrust device is compressed, with the ink cartridge withdrawn inside the barrel:


  • When clicking the pen, the thrust device is activated, pushing down the ink cartridge and locking itself in the extended position. This extension allows the pen tip to be exposed for writing.
  • When the cam body rotates and slides up the barrel, it pushes the plunger downward due to its angled mating arrangement.

This rotational motion creates the first click sound and signifies the transition from the retracted to the extended position.

  • Releasing the button causes a spring between the plastic tube and the plunger to force it upward, disengaging it from the cam body.
  • The cam body continues to rotate until it contacts the stop members, generating the second click and securing the pen in the extended position.
  • To retract the clicker pen, the button is pressed again, driving the plunger into the cam body and bypassing the stop members. The cam body rotates and strikes the plunger, producing the third click.
  • Releasing the button allows the top spring to push the plunger upward, causing it to slide and rotate until it reaches the stop members, resulting in the fourth click.
  • Throughout the process, the cam body’s rotational symmetry of 180 degrees enables consistent operation in subsequent extend/retract cycles.

2. Rolling mechanism


  • When you write, you apply pressure to the ball at the ballpoint pen tips. This pressure causes the ball to rotate as it rolls across the paper.
  • As the ball turns, it picks up ink from the reservoir and carries it onto the paper through a small channel or groove behind it. The ball acts as a barrier, preventing the ink from leaking too quickly.
  • The rolling action of the ball, combined with the controlled release of ink through the channel, allows for a consistent and controlled flow of ink onto the paper.

Related comparisons are made for you:

Pros and Cons of Ballpoint Pens

  • Convenience: Ballpoint pens are readily available and easy to use. They require minimal maintenance and can be used on various paper types without smudging or bleeding.
  • Longer life: Ballpoint pens have a longer lifespan than other pens. They typically contain more ink, allowing for extended use before needing a refill or replacement.
  • Short drying time: Ballpoint pen ink dries quickly, reducing the chances of smearing while writing.
  • Lower price: They are more affordable compared to other types of pens. Ballpoint pens are mass-produced and widely available, which helps to keep their cost lower.
  • Lack of smoothness: the ink of ballpoint pens may not always flow evenly, resulting in inconsistent thickness when writing. It can make the writing look less neat and clear.
  • Hard to remove: the ink can be difficult to remove from clothing or fabric. The ink is oil-based, so it doesn’t easily wash out with water and regular cleaning methods. This can be frustrating if you accidentally get ink on your clothes.

Types of Ink Used in Ballpoint Pens


  • Oil-based ink: This is the most widely used type of ink in ballpoint pens. It consists of a mixture of oil and pigment.
  • Gel ink: Gel ink contains pigments suspended in a gel-like substance. It provides vibrant and bold colors and flows smoothly onto the paper.
  • Emulsion ink (hybrid ink): ink that combines the characteristics of oil-based ink and water-based ink. It is created by mixing oil-based dyes or pigments with water and emulsifiers.
  • Water-based ink: Water-based ink is less common in ballpoint pens but is used in some models. It is made of water and dyes or pigments.
  • Erasable ink: A type of ink that contains thermoplastic elastomer, plasticizer, and solvent. They help erase the ink from paper surfaces easily.

Oil-Based vs Water-Based Ink

Oil-Based Ink Water-Based Ink
Solvent Volatile organic solvent Water
Drying time Quick drying Slower drying
Bleed through More prone to bleed through Less prone to bleed through
Odor Stronger odor Less odor
Versatility Suitable for writing on plastics and metals Can be used on various surfaces, including paper
Stickiness Provides an oily feel Less sticky
Stain removal Stains may be harder to remove Stains can be easier to remove with water or mild solvents


How does a ballpoint pen work? The retractable pen mechanism allows the pen tip to be extended or retracted as needed. Besides, when pressure is applied to the ballpoint tip, the ball rotates, transferring ink onto the paper.

Moreover, different types of ink, such as oil-based and water-based, offer distinct advantages and characteristics. Understanding the ballpoint pen technology and characteristics will help you make the most of this writing instrument in daily lives.

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