What is the principle of printing color sensitive label paper?

The principle of printing color thermal label paper is mainly based on physical and chemical reactions, which are explained in detail as follows:

1、 Overview of Working Principle

Color thermal label paper uses latent dyes and temperature changes to trigger a reaction to display colors, requiring the cooperation of a thermal printer. Thermal paper does not have ink cartridges inside, and its main components are the drum and print head. When thermal paper comes into contact with the print head, the high temperature generated by the print head melts the dye and acidic substances on the surface of the thermal paper into a liquid and undergoes a chemical reaction, resulting in the appearance of color on the paper.

2、 Core elements and functions

Hidden dye: A special hidden dye is used in colored thermal label paper. This dye itself is colorless, and thermal paper looks no different from ordinary paper at room temperature. Once the temperature rises, the latent dye will melt into a liquid and react with the color developer, thus revealing its color.

Thermal printer: Thermal paper requires special printer coordination, namely thermal printer. The internal structure of a thermal printer is relatively simple, without ink cartridges, and the main components are the drum and print head. The surface of the print head has many tiny semiconductor components that can heat specific areas of the paper according to the text or graphics that need to be printed.

Thermal sensitive coating: Thermal sensitive label paper is usually divided into three layers, with the bottom layer being the paper base, the second layer being the thermal sensitive coating, and the third layer being the protective layer. Thermal sensitive coating is a key factor affecting printing and storage quality. It can be designed with different activation temperatures as needed to meet the needs of printers with different performance.

Protective layer: The protective layer is located on top of the thermosensitive layer, with the purpose of protecting the thermosensitive layer, resisting chemical corrosion, preventing label contamination, and protecting the print head.

3、 Printing process

Preparation stage: Place the colored thermal label paper into the paper slot of the thermal printer and ensure that the label paper can pass smoothly through the printer.

Heating stage: When the label paper comes into contact with the print head, the high temperature generated by the print head will melt the latent dye and acidic substances on the surface of the thermal paper into liquid.

Reaction stage: The melted dye and color developer meet and undergo a chemical reaction, resulting in the appearance of color on the paper.

Output stage: Under the drive of the drum, the printed color label paper is output.

In summary, the principle of printing color thermal label paper is to use latent dyes and temperature changes to trigger reactions to display colors, and to achieve printing effects through the heating effect of thermal printers.