How does the thermal coating of color thermal label paper work?

The working principle of the thermal coating of color thermal label paper is mainly based on physical and chemical reactions. The following is the detailed working process:

Heat-sensitive coating components

The thermal coating of color thermal label paper mainly contains two key ingredients:

1.Colorless dye (leuco dye) : This dye is colorless at room temperature, but under certain conditions (such as heat) can undergo chemical reactions to show color.

2.Color developing agent: When colorless dye and color developing agent under heat chemical reaction, colorless dye will show a specific color, such as blue, purple, black and so on.

In addition, other components such as sensitizers, fillers, adhesives, stabilizers and lubricants may also be included in the thermal coating, which together act on the printing and preservation properties of the thermal paper.

Working principle

1.Reaction to heat:

When color thermal label paper is printed through a thermal printer, the surface of the print head has a number of tiny semiconductor components that are able to heat specific areas of the paper according to the printing instructions.

At the moment of contact between the thermal paper and the print head, the high temperature generated by the print head makes the colorless dye and color developer on the surface of the thermal paper melt into a liquid one after another.

The colorless dye and color developer molecules that melt into the liquid can move freely and meet, and immediately react to show the color on the surface of the thermal paper to form the required text or graphics.

2.Color display:

Because there are many kinds of colorless dyes used, the writing color of thermal paper will be different after heating, including blue, purple, black and other colors.

The speed and stability of the color development depends on the formulation of the thermal coating and the heating performance of the printer.

3.Preservation and stability:

The text or graphics printed on color thermal label paper may be affected by factors such as light, humidity, and temperature during storage, causing the color to fade gradually.

Therefore, ingredients such as stabilizers are usually added to the formulation of thermal coatings to improve the stability and light resistance of the printed content.

Matters needing attention

When using color thermal label paper, it is necessary to ensure that the heating performance of the printer matches the coating formula of the thermal paper to obtain the best printing results.

Color thermal label paper is not suitable for long-term storage of important documents or content that needs to be kept permanently, as its color may fade over time.

In summary, the thermal coating of the color thermal label paper causes a chemical reaction between the colorless dye and the color developer through the thermal reaction, so as to show the color on the surface of the paper. This working principle makes color thermal label paper widely used in printing receipts, labels and other fields.