How Do Erasable Gel Pens Work?

The working principle of erasable gel pens mainly relies on special thermosensitive ink. Here is its specific working mechanism:

1. Composition of thermosensitive ink
The ink of erasable gel pens consists of three main components:

Dye (Colorant): responsible for providing color.

Developer: helps the dye show color.

Temperature-sensitive compound: triggers the appearance or disappearance of color when the temperature changes.

2. Temperature-induced color change

The color of ink is directly related to temperature. At room temperature, the dye and the developer combine and the ink shows color.

When the rubber or friction head at the end of the pen is rubbed quickly on the paper surface, the heat generated by friction will increase the temperature of the ink to above about 60℃, at which time the denaturant will change the chemical structure of the ink and make the color disappear.

3. Color recovery after cooling (partially recoverable)

At extremely low temperatures (usually below -10℃), the disappeared color may reappear. This is because the low temperature restores the chemical structure of the denaturant to its initial state.

4. Benefits of friction erasing

Unlike ordinary erasers, the erasing process of erasable gel pens will not damage the paper surface because it erases the ink color instead of physically removing the substance on the paper.