How much do you know about such a common thermal paper?
1. Thermal paper concept
Thermal paper, also known as thermal recording paper, thermal copy paper and thermal fax paper, was first developed by the American 3M (Minesota Mining Ink Character) company in 1951. The leuco dye two-component thermal paper is a processed paper coated with a special coating. Information paper with heat-sensitive recording effect composed of a color-sensitive coating.
2. Use of thermal paper
The main uses of thermal paper are as follows: fax machines, communications, medical care, recording and measurement systems such as electrocardiographs, thermal instruments, computer networking terminal printing, trademarks, signatures (POS), etc. Among them, the use of fax machines most. With the rapid development of information technology, ticket printer technology and barcode technology have been widely used. Thermal paper has grown rapidly in the field of barcode recording information and ticket printing due to its unique properties, the advantages of rapid image generation and convenient barcode labels.
3. Classification of thermal paper
In terms of function, thermal paper can be divided into ordinary thermal paper and three-proof thermal paper. Three-proof thermal paper is coated with a protective layer on the heat-sensitive chromophoric layer to give the three-proof thermal paper better waterproof, oil-proof and anti-friction properties. It is mainly used in the high-end market.
In terms of structure, thermal paper is mainly divided into two categories. One is physical thermal paper that uses heat to physically color pigments to achieve the recording effect. Sublimation type, etc., of which the representative is melting transparent thermal paper, which is widely used in medical ECG and EEG, etc.; the other type is the use of chemical reaction under the action of heat to achieve color development This kind of thermal paper is divided into two-component metal compound chromogenic thermal paper and leuco dye two-component thermal paper.
4. Principle of color rendering of thermal paper
The principle of color development of molten transparent thermal paper is to coat a layer of opaque wax as the surface layer on the black base paper. After the action of the hot pen, the opaque waxy material is melted and transparent, and the color of the bottom layer of the base paper is revealed. image. The color development principle of metal compound color thermal paper is based on the mixing of heavy metal salts of fatty acids and reducing agents. The fatty acid salts are melted and reacted with reducing agents by heating and heating, so that the heavy metals are reduced to free color. The color development principle of leuco dye-type thermal paper is based on the mixing of a leuco dye containing an internal alicyclic ring with a color developer. Under the action of heat, the color developer and the leuco dye are heated and melted to react and develop color.
5. How long can thermal paper printing be stored?
The main factor affecting the quality of thermal printing paper is the thermal coating or protective layer. If the coating of the thermal paper is not uniform, it will cause the printing to be dark in some places and light in some places, and the printing quality will be significantly reduced. If the chemical formula of the thermal coating is unreasonable, it will lead to the preservation of the thermal printing paper. The time has become very short, good printing paper can be stored for 5 years after printing (under the condition of normal temperature and avoid direct sunlight), and now there is a long-term thermal paper that can be stored for 10 years.
In addition, the protective coating is also critical to the storage time after printing. It can absorb part of the light that causes the thermal coating to react chemically, slow down the deterioration of the printing paper, and protect the thermal components of the printer from damage, but if The uneven protective coating will not only greatly reduce the protection of the thermal coating, but even the fine particles of the protective coating will fall off during the printing process, rubbing the thermal components of the printer, resulting in damage to the thermal components of the printing.